STAAD PRO V8i Syllabus: Chapter- 1: 1. Introduction To Structural Engineering 2. What is a Structure? 3. About STAAD.Pro V8i 4. Getting Started Chapter- 2: 1. Starting STAAD.Pro V8i 2. Methods Of Model Generation 3. Translational Repeat 4. Circular Repeat 5. Insert Node 6. Add Beam Chapter- 3: 1. Run Structure Wizard 2. Generation Structure Models 3. Merging the Generated Model in STAAD.Pro 4. Importing CAD Models Chapter- 4: 1. Support Specification 2. Support Page 3. Member Property
4. Member Offset Chapter- 5: 1. Loading – 1 2. Loading – 2 3. Wind Load Generation 4. Assigning Wind Loads Chapter- 5: 1. Analysis 2. Concrete Design 3. Time History Analysis Chapter- 6: 1. Introduction to FEM 2. Plate 3. Surface 4. Meshing Chapter- 7: (Slabs) 1. Desgin Of Slab 2. Design Of One Way Slab 3. Design Of Two Way Slab 4. Design Of Staircase 5. Design of Bridge using STAAD .Beava
Chapter- 8: (Bridge Deck Preprocessor Worked Example) 1. Bridge Deck Preprocessing Using STAAD.Beava Chapter- 9: (Steel) 1. Design Of Steel Structures 2. Member Specification Table Member Property Chapter- 10: (Seismic Loads Worked Examples) 1. Calculate Natural Frequency of a Building By Response Spectrum Analysis 2. Calculate Natural Frequency of a Building By Rayleigh Method 3. Calculate Natural Frequency of a Building By Modal Shape Chapter- 11: (Wind Load Intensity Worked Examples) Calculate Wind Load Intensity In a Building
Chapter- 1: 1. Introduction To Structural Engineering 2. What is a Structure? 3. About STAAD.Pro V8i 4. Getting Started
1. Introduction to Structural Engineering Structural Engineering is a field of civil engineering dealing with analysis and design of structures that support or resist loads. Structural engineering is usually considered a speciality within civil engineering, but it can also be studied inits own right. Structural engineering are most commonly involved in the design of buildings and large nonbuilding structures but they can also be involved in the design of buildings and large non-building structures but they can also be involved in the design of machinery, medical equipment, vehicles or any item where structural integrity affects the item‟s function or safety. Structural engineers must ensure their design satisfy given design criteria, predicated on safety or serviceability and performance. Buildings are made to endure massive loads as well as changing climate and natural disasters. Structural engineers are responsible for engineering design and analysis. Entry-level structural engineers may design the individual structural elements of a structure, for example the beams, columns and floor of the building. More experienced engineers would be responsible for the structural design and integrity of an entire system, such as building. Structural engineering depends upon a detailed knowledge of loads. To apply the knowledge successfully a structural engineer will need a detailed knowledge of mathematics and of relevant empirical and theoretical design codes.
2.What is a Structure? A Structure can be defined as an interrelated or independent parts forming a more complex, unified whole and serving a common purpose. For instance, a building can be defined as a structural system designed and constructed to support and transmit applied lateral and gravity loads safely to the ground without exceeding the allowable stresses in its members. The super structure is the vertical extension of the building above the foundation. Columns, beams and load bearing wall support floors and roof structures. The substructure is the underlying structure forming the foundation of the building.
Types of Structures: 1. Space Structure:
Suitable for any arrangement of model geometry and loading. Allows three dimensional Structures. Allows loading in any direction. Allows deformations in all three global axes. Coordinate system tracks right hand rule.
2. Plane Structure:
Suitable only for two dimensional modes in x y plane with no loading or distortions upright to this plane. All loads and distortions are in the plane of the structure.
3. Truss Structure:
Allows loading in any direction, but members only deliver axial resistance. Members dismiss resist bending or shear loads. Allows three dimensional structures. Allows distortions in all three global directions. Coordinate system tracks right hand rule.
4. Floor Structure:
Suitable for two dimensional models in x z plane with loading and distortions perpendicular to this plane. All loads and distortions are corresponding to the global y axis.
3. About STAAD.Pro V8i STAAD.Pro V8i is the leading Structural Analysis and Design Software from Bentley. The Letter “i” stands for intutive, interactive, incredible and interoperable. STAAD.Pro is the professional‟s choice for steel, concrete, timber, aluminium and cold formed steel design of virtually any structures including culverts, pertrochemical plants, tunnels, bridges, piles and much more. Bentley sounds V8i is the most complete and noteworthy release in its history, which took a total investment of over a billion dollars and extents across the vast array disciplines with fundamental subject and assignment endures to be Sustaining Infrastructure.
STAAD.Pro is a overall resolution program for execution of analysis and design of a extensive variation of types of structures. The simple three activities which are to be carried out to accomplish that goal – a) model generation, b) the calculations to obtain the analytical results and c) result verification – are all simplified by tools enclosed in the program‟s graphical environment. This guidebook comprises three sample tutorials which guide the user to execute those 3 activities. 1. Graphical model generation services as well as text editor based commands for generating the calculated model. Beam and column members are characterized using lines. Walls, slabs and panel type objects are characterized by means of triangular and quadrilateral finite elements. Solid blocks are characterized by means of brick elements. These functions allow the user to generate the geometry, assign properties, orient cross sections as wanted, assign materials like steel, concrete, timber, aluminium, specify supports, apply loads obviously as well as have the program produce loads, design parameters etc. 2. Analysis engines for executing linear elastic and p delta analysis, finite element analysis, regularity in extraction, and response spectrum analysis & time history analysis.
3. Design engines for code inspection and optimization of steel, aluminium and timber members. Reinforcement designs for concrete beams, columns, slabs and shear walls. Design of shear and moment acquaintances for steel members. 4. Result inspecting, result confirmation and report preparation tools for Inspecting displacement diagrams, bending moment and shear force diagrams, beam, plate and solid stress contours, etc. 5. Exterior tools for actions like import and export of data from and to other broadly recognized formats, links with other general softwares for Place areas like reinforced and pre stressed concrete slab design, footing design, steel connection design, etc. 6. A library of visible utilities called Open STAAD which permits users to Right of entry STAAD.Pro‟s internal tasks and practises as well as its graphical instructions to tap into STAAD‟s catalogue and link input and output data to third-party software inscribed using languages like C, C++, VBA, FORTRAN, Java, etc. Thus, Open STAAD allows users to relation in-house or third-party presentations with STAAD.Pro. 4.0 Getting Started STAAD.Pro V8i Application Window: STAAD.Pro V8i screen is shown below. The screen has five major elements as shown below.
1. Menu bar. 2. Tool bar. 3. Page control. 4. Main Window. 5. Data Window. In STAAD.Pro V8i: Geometry is the “Elements of your Structure”. The Elements are given below:
Nodes Members (beams and columns) Plates (Slab, Walls and Raft Foundations) Surfaces (Slab, Walls and Raft Foundations)
Nodes: Stiffed Joint with 6 reactions. It is located at each end of the Beam and each corner of the Plate Nodes considered the essence of the geometry of any structure in STAAD.Pro. Each node holds the following informations:
Node Number. Node Coordinates in XYZ space.
Beam: Any member in the structure, that can be beam, column, bracing member or truss member. Beams are actually defined based on the Nodes at their ends. Each beam holds the following information:
Beam Number. The Node numbers at its ends.
Plates: A thin shell with 4 node shaped element. It can be slab or wall element. Each plate will holds the following information:
Plate Number. Node Number at each corner of it.
Surface: A thin shell in green color with mutli-nodded shape starting from 3 nodes and more. It can be anything of slabs, walls and raft foundations. It holds the following information:
Surface Number. Node Numbers at each corner of it.
Hardware Requirements: The following requirements are suggested minimums. Systems with increased capacity provide enhanced performance.
PC with Intel-Pentium or equivalent. Graphics card and monitor with 1024×768 resolution, 256 color display (16 bit high color recommended). 128 MB RAM or higher.
Windows NT 4.0 or higher operating system. Running it on Windows 95 & Windows 98 systems is not recommended as performance may be degraded. The program works best on Windows 2000 and XP operating systems. Sufficient free space on the hard disk to hold the program and data files. The disk space requirement will vary depending on the modules you are installing. A typical minimum is 500MB free space. A multi-media ready system with sound card and speakers is needed to run the tutorial movies and slide shows.
Chapter- 2: 1. Starting STAAD.Pro V8i 2. Methods Of Model Generation 3. Translational Repeat 4. Circular Repeat 5. Insert Node 6. Add Beam
1. Starting STAAD.Pro V8i Creating a Project: Once you stared the STAAD.Pro application follow the instructions: 1. In the Project Tasks box, click New Project. 2. A New Project dialog box appears is shown below:
3. Before starting a project, you must be aware of the type of structure. The structure type can be defined as Space, Plane, Floor, or Truss.
Space: A SPACE structure, which is a three-dimensional framed structure with loads applied in any plane, is the most general. The loading causes the structure to deform in all 3 global axes. Plane: The type of geometry, loading and deformation are restricted to the global X-Y plane only. Floor: The geometry of structure is kept at the X-Z plane. Truss: The structure transmits loading by pure axial action. Truss members are considered to be in capable of carrying shear, bending and torsion.
4. Set the length units and loading units and click Next button. Note: The units can be altered later if needed, at any point of the model creation. 5. Now Where do you want to go? dialog box appears. You have specify the method for building
Add Beam: Sets the program in the Snap Node/Beam dialog and snap grid to construct your model by creating new joints and beams using the construction grid, drawing tools and spreadsheets. Add Plate: Sets the program up with the Snap Node/Plate dialog to construct your model by creating new joints and 3-noded and 4-noded plate elements using the construction grid, drawing tools and spreadsheets. Add Solid: Sets the program up with the Snap Node/Plate dialog to construct your model by creating new joints and 8-noded solid/brick elements using the construction grid, drawing tools and spreadsheets. Open Structure Wizard: Opens the library of readymade structure templates which can be extracted and modified parametric model standard, parametric structural templates for trusses, surfaces, bay frames and much more. Open STAAD.Editor: Allows you to build your model using STAAD syntax commands (non-graphical interface) through the STAAD editor. Edit Job Information: Automatically opens the Job Information dialog box which provide information about the job (i.e. client‟s name, job title, engineers involved, etc.) before building your model.
2. Methods Of Model Generation STAAD.Pro V8i consists of three parts:
Pre Processor: Generates the model with all the data needed for the analysis. Analysis Engine: Calculates displacements, member forces, reactions, stresses, etc.
Post Processing: Displays the results of the analysis and design.
Creating Nodes: When you select the Nodes command in geometry menu, it shows a dialog box where you can enter the joint coordinates.
After creating the joint i.e. entering the coordinates, you can able to see the joint in the modelling area. JOINT COORDINATES i1, x1, y1, z1, (i2, x2, y2, z2, i3) REPEAT n, xi,yi1, zi1, (xi1, yi2, . . . . xin, yin, zin) REPEAT ALL n,xi1, yi1, zi1, (xi2, yi2, zi2, . . . . xin, yin, zin)
Enhanced Grid Tool: The options in Snap/Grid Node tools in the geometry menu have been improved to 1. Allow multiple grids to be created. 2. Import a DXF file and use it as be created. 3. Import grid files created in different STAAD.Pro model.
Beams, plates and 8 nodes solid element can be created using the suitable Snap/Grid tool. When this function is propelled, the following dialog is opened which includes a Default Grid. This grid will be of type „linear‟, there are also options to create Radial, and Irregular grids. As new grids are added or modified, the information is stored in the STAAD.Pro data folder with a GRD allowance that permits other STAAD.Pro file to re-use these defined grids. To alter the starting of this grid, click on the Edit button to show the existing grid properties.
The current plane of the grid is set by selecting the required option. This can rotated about one of the global planes by selecting the axis of rotation and setting the angle. The origin of the grid is marked on the graphics, with a small circle. The location of the origin, specified in global coordinates, can either be defined explicitly in the given X.Y and Z coordinates, or it can be set to the coordinates of an existing node by clicking on the icon and then on the node itself in the graphical window. Note that at this point the origin coordinate is updated. The construction lines are used to specify how many gridlines are created either side of the origin, the spacing between the gridlines and if there should be a skew in degrees along either axis. Click on the OK button to accept these settings. Additional grids can be defined by clicking in the Create button. Three different types of standard grid can be created:
Linear Radial Irregular
The type of the grid required can be selected from the drop down list available at the top of the property sheet. Each new grid should be identified with a unique name for future reference. The functionality for each type of grid is given below: Linear:
Two dimensional system of regularity spaced linear construction lines creating a plane of snap points. Plane is defined as being coincident with the global XY, XZ or YZ planes or at an angle skewed with respect to the global planes. Location of the origin can be defined with respect to global X, Y and Z coordinates systems.
Radial:
Two dimensional system of regularly spaced radial and circumferential construction lines creating a plane of snap points. Plane is defined as being coincident with the global XY, XZ and YZ planes or at angle skewed with respect to the global planes. Location of the origin can be defined with respect to global X, Y and Z coordinates systems. Well suited for drawing circular models using piece-wise linear techniques.
The settings for a Radial grid are defined in the following window:
The Plane, Angle of Plane and Grid origin option are as for the linear. Irregular:
Two dimensional system of regularity or irregularly spaced linear construction lines creating a plane of snap points. Plane is defined as being coincident with the global XY, XZ or YZ planes or at an angle skewed respect to the global planes or at an arbitrary plane.
The settings for an irregular grid are defined in the following window:
3. Translational Repeat Translational Option allows to copy the entire structure or a portion of the structure in a linear direction. We may generate one or more several copies of the selected components. Select the structural elements to repeat. Select Geometry→ Translational Repeat option from the geometry menu or Click Translational Repeat Icon Translational Repeat dialog box appears as shown below:
. The
Global Direction: Choose any one of the three possible global direction along which the selected structural elements should be copies. No of Steps: Specify the numbers of steps to repeated you need. Default Step Spacing: Type the default spacing between steps in the edit box in current length units. For each step, the default value of the spacing will be what we provide in the Default step spacing box. We can change the spacing of individual steps if we choose to do so. Step Spacing Table: This table consists of two columns: Step and Spacing. We can change the spacing of any type in the table. Renumber Bay: This is the way of instructing the program to use a user-specified starting number for the members generated in each step of the translational repeat activity. Geometry Only: The Translational Repeat allows the copying of the elements without having their loads properties, steel design parameters, etc. being copied with it. By default (when the Geometry Only option is not checked) all loads, properties, design parameters, members releases, etc. on the selected elements will automatically be copied along with the elements. By checking the option labelled Geometry Only, the translational repeating will be per formed using only geometry data. Link Steps and Open Base: If you want to automatically connect the steps or copies by new members, along the specified global directions, check the Link Steps check box. In other words, the Link Steps option is applicable when the newly created units are physically removed from the existing units and when one wishes to connect those using members. To avoid joining the base of the copied structures, check the Open Base box. Here you can see the Frame model copied using the Translational Repeat option:
4. Circular Repeat Circular Repeat allows to copy of the entire structure on an portion of if in a circular direction. Select the structural elements to repeat and select the Circular Repeat option from the geometry menu. The 3D Circular dialog box appears as shown in the figure.
Axis of Rotation: Click the radio button to choose the axis of rotation for repeating the selected components.
Through: The new highlight node button selects the Node on Plane. Click on this icon to be able to select the node from the main model. Once the cursor changes the shape, simply select a node from the model. The Node and Point boxes will automatically fill up with the correct information. Otherwise, type an existing Node number or location Point coordinates to define the axis of rotation. Use this as Reference Point for Beta angle generation. In previous versions of STAAD.Pro, one limitations of the Circular Repeat feature was that the member orientation was not taken into consideration during the circular generation. This limitation has been addressed now. If the Use this as Reference Point for Beta angle generation switch is turned on, the point through which the axis for circular repeat operation passes will be used as the member reference point for all the generated members. This point along with the local X axis of the generated member will define the local X-Y plane of the member and hence the member orientation gets automatically set. Total Angle: Provide the total sweep angle of rotation between the original structure and the last copied structure. No of Steps: Provide the number of steps we want over the specified Total Angle. Link Steps and open Base: If you want to automatically connect the steps by new members, check the Link Steps check box. To avoid joining the base of the copied structure, check the Open Base box. The Circular Repeat. Rotate and Mirror dialog boxes have been enhanced to remain open so that the selection beams, nodes, etc. can be accomplished even while the box is open. Also, selection of critical points such as the node, point or plane where the axis of rotation crosses can now be selected graphically while the box remains open. This eliminates the inconvenience in the past where if this location was known before selecting one of the geometry options, the box had to be closed down to determine the location first.
1. Select the objects to be copied.
2. Click Geometry→ Circulation Repeat. 3. In 3D Circular dialog box, select the Axis of Rotation and Point or Coordinate of Axis. 4. Type the Total angle and No of Steps. 5. Click OK.
5. Insert Node This facility allows the user to insert node on an existing member. The member is split into the corresponding number of segments with automatic generation of node and member numbers, member properties and loads. If you choose this option, the Insert Node cursor appears. By using that cursor, you can select the member to split. The Insert Node dialog appears, as shown below:
Beam Length: This lists the distance from node A to node B along the beam to be split. New Insertion Point: Provide the Distance from the start node of the member in current length units. Alternatively, provide Proportion of the total length of the member to position the new node. Click Add New Point to add the node. Add New Point: After providing the Distance or the Proportion, click on the Add New Point to add the node.
Add Mid Point: To split the member into two segments, click on this button. Add n Points: To divide the beam in a number of equal segments, provide the number of intermediate points in the n = edit box and click on Add n Points. Note that this value should be an integer. Insertion Points: The locations of the newly created points are listed in this list box, shown as the distance from the start node of the member, To accept the new nodes that appear in the Insertion Point list box, click the OK button. Remove: To remove a node from the list of inserted nodes, highlight the desired node and click on this button. Enhancement of Insert Node Operation: Users can now select multiple members and split the members at a given fractional position or a specified distances from the starting node positions. The new feature will enable the users to perform the operation in one sight command which will reduce the modeling time. New point by distance: Specify the distance in current length units at which the beam is to split. The value for the distance is entered in the Distance edit box and is measured from the start node of the beam. New point by proportion: This option allows the users to specify the distance in terms of a ratio. For example, to split a beam at the midpoint, enter 0.5 as the proportion .To split the beam at quarter points, use a proportion value of 0.25. Add mid point: The beam are split at their midpoints.
Add „n‟ points: To split a beam by inserting „n‟ number of points, use this option. The beams are split up into n+1 segments.
6.Add Beam This option in geometry menu allows you to add members by connecting existing nodes. Choosing this option brings up the following sub-menu.
Add Beam from Point to Point: In prior versions to STAAD.Pro, the Add Beam option was a facility for adding a beam between two existing nodes. This has now been extended to be able to create beams from nodes that have not been previously defined. The nodes can now be dynamically generated at the time of creating the beam similar to the way beams are created using the Snap/Grid Beam command. To create a beam dynamically without the start and end nodes defined, go to Geometry| Add Beam |Add Beam from Point to Point from the main menu. The Add Beams cursor appears. Click on any point on the existing beam where the starting node of the new beam will lie. if an existing node is not present at that point, a dialog box will prompt for a new node to be created.
Click on Yes to create a new node. The Insert Nodes dialog box will prompt for the exact location where the nodes is to be created. once the desired node or nodes have been input that box, click on the OK button to generate the new nodes on the selected beam. If the new node input is not within a close proximity of the point clicked on the screen, no “draggable”line will be shown. Click on the new node to start the creation of the beam. Then, drag the mouse to another existing node location or repeat the same steps again to dynamically create another new node.
Chapter- 3: 1. Run Structure Wizard 2. Generation Structure Models 3. Merging the Generated Model in STAAD.Pro 4. Importing CAD Models
1. Run Structure Wizard The Run Structure Wizard option offers a library of ore-defined structure prototypes, such as Pratt truss, North light Truss, cylindrical Frame, etc. We may parametrically generate a structural model and then transfer and superimpose it on the current structure. When we select the Run Structure Wizard option from the Geometry menu, the Structure Wizard window appears as shown below.
The Protype Models and Saved User Models options on the top of the left side of the screen. If the Prototype Models option is selected, the Model Type will list the types of prototype structure available as shown below. If the Saved User Models option is selected, the Model Type will display the list previously done and saved models by the user.
Adding and Deleting items to the library: Items can be deleted or added with certain settings from and to the list. The modified item list can be saved in different files and called when requires. In brief , the item list is customizable.
To insert any customized item under any Model type, select that Model Type and click the mouse at the bottom of the same pane. Right-click the mouse and from the context menu, select Add Plug-in and you can load the corresponding “.dll” file. We can also delete a particular structural item by selecting that particular item and by clicking the Delete Model Plug-in from the context menu. A structural item under any Model Type may be renamed by using Rename Model Generator from the context menu. The customized list of the Prototype can be saved in different files. By default, STAAD.Pro/Structure Wizard uses the default .STP file. We can save any changes in this file. Also changes can be saved in any file other than default .STP. To save the changes, select Save As…. from the File menu in the Structure Wizard window. Provide the path and name of the .STP file and press OK. To open any .STP file to use the customized Structure Libraries, select the File| Open menu option from Structure Wizard main menu. Specify the path and name of the .STP file and press OK. Use the View, Zoom, Pan and Rotate icons to change the orientation of the model.
2.Generation of Structure from Models In this section, the process of generating a structural model and combining it with the existing STAAD.Pro structure will be explained using a Howe Roof Truss. Follow these steps to create the other truss types also.
Selection of Unit: The unit of the length should be specified before the generation of a model. From the File menu, click Select Unit and the Select Unit dialog box will appear as shown below. We can select any unit of length from Imperial or SI/Metric system of units. Model Type: Truss Select the Howe Roof structure type under model type Trusses. Drag the item into the right side window and release the button. The Select Parameters dialog box will appears to specify the Truss parameter as shown below:
After defining the parameters click Apply and the prototype truss will appears with the X, Y and Z axes on the screen.
Right click in the right side window containing the generated model. The context-menu will display the options Change Property, Scale and Delete. We can edit the value of the parameters by clicking the Change Property, which will pop-up the select Parameters dialog box. Enter the length, height and width of the truss and the number of bays along those directions. To modify the spacing of individual bays, click the browse button and in the dialog box that appears, type new spacing and click OK. Click the Apply button to parametrically generated the truss model. Click Close to finish. We can re-scale the model in X, Y and Z directions separately using Scale from the context menu. You can also delete the particular model by clicking Delete from the context menu.
3.Merging the Generated Model to STAAD.Pro Select the Merge Model with STAAD.Pro sub menu from the File menu to combine the generated model to the current STAAD.Pro structure.
The structure Wizard window will now close. In the STAAD.Pro window, the Paste Prototype Model dialog box will appears., in which we can type the shift of the origin of the Structure Wizard model from the origin of the STAAD.Pro axis system or we can type coordinate of the node of the STAAD.Pro structure with which we can want to connect the Structure Wizard model or click on the Reference Pt button to connect the node of the existing structure in STAAD.Pro with the Structure Wizard model by clicking on the joints where they will be connected. Click OK to finish.
In the Frame Models Continuous Beam, Bay Frame, Grid Frame and Floor Grid have similar parameters in the Select Parameter dialog box. Type values for Length, Height & Width and number of bays for each. To modify the spacing of the bays, click the browse button and in the dialog box that appears, type new spacing and click OK. Click the Apply button to the parametrically generated model. The Cylindrical Frame, Reverse Cylindrical Frame and Circular Beam have similar Parameter in the Select Parameter dialog box. Type values for Length, Radius, Angle and number of bays along length and periphery. To modify the spacing of bars, click the browse button and in dialog box that appears, type new spacing and click OK, Click the Apply button to parametrically generate the model.
4.Importing CAD Models This feature can import CAD models, has two separate utilities, Scan DXF and STAAD Models.
Scan DXF: If the geometry of the model is created using the drawing program like AutoCAD and saved in a DXF file format, it can be imported using this option. After dragging the Scan DXF icon into the right side window, a Open dialog box appears and noe=w locate the “DXF” file, which we want to open, select that file and press OK. This feature supports the limited number of CAD entities like Line, 3D-Polyline and 3D-Face. STAAD Models: This allows the geometry of the previously created model to be imported and altered. After dragging the STAAD Models icon into the right side window, an Open dialog box will appear. Now locate the “STD” file which you want to open, select that “STD” file and press OK. The geometry from that STD file will be imported. That model can be scaled up or down along the global X, Y and Z directions by clicking the right mouse button, choosing the Scale option and provide the desired values.
Chapter- 4: 1. Support Specification 2. Support Page 3. Member Property 4. Member Offset
1.Support Specification This allows the user to define the support conditions of the structure by providing fixed, pinned, roller, inclined, spring supports, etc. Supports can defined and assigned from the General| Support page also. This menu option is used to specify the supports on the structures. The Support Specification menu offers several sub-menu options, as follow. Click Commands→ Support Specifications.
Pinned: This allows user to create the pinned support tag and assigned it to the selected nodes. A pinned support is restrained in all three translational degree of freedom and free in the 3 rotational degrees of freedom.
Fixed: This allows the user to create a fixed support tag and assign that to the selected nodes. A fixed support is restrained in all 6 degree of freedom.
Fixed But / Spring: This allows the user to create various types of roller, hinge and spring support with specified restrained degrees of freedom and to assign them to selected nodes. Enforced: The Enforced support is the same the fixed support except that the restrained degrees of freedom are defined in terms of being stiff springs. Enforced supports are identical to the „FIXED‟ type of supports in most respects. The real advantage of using the ENFORCED type lies in the fact that is enables STAAD to accept loads such as support displacements loads in case of plates and solids. Support displacement loads are not permitted for plates and solids if the FIXED support type is used. So, for structures without these characteristics, the FIXED type of support offers the same level of functionality as the ENFORCED support type.
Enforced But: Enforced But support type is the same as the “Enforced” support except that we have the choice on the degrees of freedom we wish to restrain. For example, we can select Enforced But and restrain just the FX, FY and FZ degree of freedom and let the remaining 3 free to deformation. Inclined: This allows the user to create supports that restraints in an axis system that is inclined with respect to the global axis system. There are two aspects defining the inclined supports:
The reference point which inclined axis system. The restraints, releases and springs.
Foundation: To define a spring support for an isolated footing, click the Footing radio button. Provide the dimension of the footing in current units settings and choose the Direction of the spring action. Provide the soil Sub-grade value in the edit box. Click the Add button to add the foundation support tag to the structure or click Assign to assign this support to selected nodes.
Elastic Mat: In this method, the area is calculated using a Delaunay triangle principle. Hence the candidates for this options are nodes which define the mat. To achieve best results, one needs to ensure that the contour formed by the nodes form a convex hull. Plate Mat: If the foundation slab is modeled using plate elements, the spring supports can be generated using an influence area calculated using the principles used in determining the tributary area of nodes from the finite element modelling standpoint. Hence the candidates for this option are the plates which define the mat. When the mat is modeled using plates. this produces superior results than the ELASTIC MAT type.
2.Support Page When the General | Support Page is opened, a Supported Nodes tables and a Supports dialog box appears in the data area. We may specify supports in two ways. We must first create Support Specification and then select the nodes to which this support is to be attached to. Alternatively, we may first select the nodes and then specify a support to be assigned to the selected nodes. In second case, a new Support Specification is created along with a support reference number. Also note that the Assign button become active if we have already selected the nodes to which the support is to be applied. Supported Nodes Table list all nodes for which supports have been defined. The type of support is also displayed. The Supports dialog box allows us to define supports and assign them to nodes. All supports that have been defined for the model are listed in the Supports dialog box.
Create: The Create button is for creating the supports to be applied on the structure. When you click this button Create Support dialog box appears. Edit: For certain types of supports, the parameters of the support can be modified after the support is created. The Edit button is available for that purpose. To do this, first select that support type from the list. Click on Edit and dialog box corresponding to that support will be re-displayed, allowing for changes to be made.
Delete: Use this button to delete a previously assigned support. Assignment Method: The options under the Assignment Method offer different choices for assigning supports to the structure. Assign To Selected Nodes: To assign a support to selected nodes, first select the support from the supports dialog box. The support selected is highlighted. Then select the nodes to which this support is to be assigned. When all the desired nodes are selected, click the Assign To Selected Nodes radio button, then click the Assign button. Assign To View: To assign a support to all free nodes in a view, first select the support from the Supports dialog box. The selected supported is highlighted. Select the Assign To View radio button, then click the Assign button. All free nodes in the structure are assigned this support after getting the confirmation. Use Cursor To Assign: To assign a support to nodes using the cursor, first select the support from the Supports dialog box. The selected support is highlighted. Select the Use Cursor To Assign radio button, then click the Assign button. The button will appear depressed and label will change to Assigning. Make sure that the Nodes Cursor is selected so that we can select the nodes. Using the cursor, click on the nodes to which this support is to be assigned. Click on the Assign button again to finish. Assign To Edit List: To assign a support using a typed list of node numbers, first select the support from the Supports dialog box. The selected support is highlighted. Select the Assign To Edit List radio button, then type the list of node numbers and click the Assign button.
3.Member Property This allows the user to provide the cross sectional properties of members with or without the material specification. The same options can be gained access from the General | Property page. The Member Property menu option is used to create the property tag and then assign the specified property tag to select members through the Property Page. Alternatively, we may first select members and then define the member property to be assigned to these members. The Member Property menu offers several sub-menu options as shown below:
Prismatic: This allows the user to assign Circular, Rectangular, Tee, Trapezoidal, General, etc. Cross sections to the frame members. When we select the Prismatic option, the Property dialog box appears as shown below. Also note that the Properties dialog box also opens simultaneously letting us utilize some of the other operations available from that dialog box.
Material: Check this box and select the material from the drop down list if the new member property tag should include the materials constants. Circle: To define a circular section, click on the Circle tab as shown in the previous figure. Enter the section diameter YD and select the material.
Rectangle: To define the rectangle section, Click on the Rectangle tab. Enter the height YD and width ZD of the section and select the material.
Tee: To define a tee section, click on the tee tab. Enter the height YD, width ZD stem height YB and stem width ZB and select the material.
Trapezoidal: To define a trapezoidal section, click on the Trapezoidal tab. Enter the height YD, top width ZD, bottom width ZB and select the material.
Tapered Tube: This allows the user to specify a I-section having a varying depth over the length of the member by using 7 parameters as shown below:
4.Member Offset The beams and columns of structure are characterized by lines in the computer model. In the actual structure, a beam spans distance which in the clear span between the faces of columns. But in the computer model, the line for the beam spans among the centerlines of the column. The half depth portion of either column is significantly stiffer than the beam itself from the stand point of bending. To take benefit of this extra stiffness, we may affirm that the start and end faces of the beam are offset from the node by a distance identical to the half-column-depths.
Member offsets can be specified in other situations too. Examples are
When a bracing member does not meet the node which is defined in its incidence list. A girder and top slab in the bridge where the centerline of the girder is several inches below the centerline of the slab.
This facility becomes very useful when the user wants to have the structural parameters of a member viz. shear force, bending moment by considering the clear distance of the member between the supports. This facility can accessed from the General | Specification also. When you select the offset menu option in the command menu, the Member Specification dialog box appears as shown below.
Location: Location defines the offset end of the member. Start is the starting point of the member and End is the Ending point of the member. Start and End depends on the Member Incidence of the member. Selecting one of these options defines the member offset to be at the start point or at the end point of the member. Direction: Choose the Local for assigning the offsets in the local axis system. Otherwise, choose the global axis system.
Offsets: Type the offset distance from the joint in the three global directions. Click the Add button to add this specification to the structure or click Assign to assign the specification to selected member as well as add this specification to the structure.
Chapter- 5: 1. Loading – 1 2. Loading – 2 3. Wind Load Generation 4. Assigning Wind Loads
Loading – 1 In STAAD.Pro V8i, loads in a structure can be detailed as Dead load, Live load, Wind load, Snow load, Seismic load, temperature load and fixed-end member load. STAAD.Pro V8i can also calculate the self-weight of the structure and make it as uniformly distributed loads (UDL) in analysis. Self-weight of the members can be applied in any desired direction. Click Commands→ Loading→ Primary Loading.
Now the Create New Definitions / Load Cases / Load Items dialog box appears. Now you have to define the loads, then click Add button.
Dead Load or Self-weight: Self-weight of all active members of the structure are calculated and applied as a uniformly distributed load. Please note that the property of the member must be defined before this command used.
Direction- Specify the direction in the self-weight load is to be applied by clicking on the X, Y or Z buttons. Factor- Specify the factor with which the calculated self-weight are to be multiplied. A negative value indicates that the load is applies along the negative direction of the selected axis.
Nodal Load: Nodal loads is the combination of forces and moments, it may be applied to any free node of a structure. These loads act in the global coordinate system of the structure. Two options are available under Nodal Load: Node and Support Displacement. Positive value forces acts in the positive coordinate directions of the axis.
Member Load: The Member Load tab allows the user to apply loads on the span of frame members.
Concentrated Load: To specify a concentrated force or moment, click the Concentrated Force or Concentrated Moment tab. The data items are explained below.
Linear Varying Load: The load is applied over the entire length of the member, varies with respect to the distance.
Loading – 2 Area Load: This allows the user to apply load over area, which will be distributed on surrounding beams based on the one way distribution. This load is a one-way distributed pressure load on members that circumstances a panel. Enter the value of area load in current units. This load always acts along the positive local y direction on the two longest member on each panel.
Note: Area load should not specified on members declared as Member Cable, Member Truss or Member Tension.
Floor Load: User can apply the load over the panel, which will be distributed on surrounding beams based on a two-way distribution. This load is two-way distributed pressure load on members that circumscribe a panel. The data items are explained below: Load – Floor load value in the current units. This load will act parallel to the global vertical axis. Direction – The floor may be considered as acting perpendicular to plane of the panel on which it is defined. This is normal load static condition. Range – Define X Range/ Y Range/ Z Range. Specify the location of the floor using the Define X Range option. The load will be calculated for all members lying between this range. One Way Distribution – Check the box for one way distribution to get a one way type distribution of the pressure. In such cases, the program find out the shorter side of the panel. It then divides the load in between the long direction beams. No load is generated by this option if the panel is square in shape.
Plate Load: The Plate Load tab allows the user to apply elements loads. The Plate Load tab offers several sub-menu options as shown below.
Pressure On Full Plate:
Load – W1 is the variable using which the pressure value is defined, in pressure units. Direction – The load may be applied along the local Z – axis, or along one of the global X, Y or Z – axis (GX, GY, GZ)
Concentrated Load:
Use this option to define a concentrated load that acts on specific point within the boundary of the element. If a load acts at a node point of an element, it is advisable to apply it using the Nodal Load option described in earlier pages. Load – The magnitude of load is specified in the box alongside Force. X and Y define the location of the load, in terms of the distance from the origin of local X and Y axes of the element. Direction – The load may be applied along the local Z-axis, or along one of the global X, Y or Z – axis (GX, GY, GZ). Partial Plate Pressure:
To Specify a uniform pressure on the entire element or a non user specified portion of the element, use this facility. The data items are explained below:
Load – The element pressure (force per unit area) or Concentrated load (force unit). For concentrated load the values of X2 and Y2 must be omitted, while X1 and Y1 must be specified. X1, Y1, X2, Y2 – For element pressure (force per unit area), these values represent the coordinates of the rectangular bpundary on which the pressure is applied. If X1, Y1, X2 and Y2 are all zero; the pressure is applied over the entire element. If X1 and Y1 are specified but X2 and Y2 are omitted, then W1 is treated as concentrated load. Direction – GX, GY, GZ represent the global X, Y and Z direction along which the pressure may be applied Local Z indicates that the pressure is applied normal to the element in the local Z direction. Trapezoidal: To specify a trapezoidal varying pressure load on a plate, select the Trapezoidal tab. The load is applied over the entire element in the local Z direction, varying along the positive local X or Y direction. The data items are explained below.
Direction of Pressure – GX, GY and GZ represent the global X, Y and Z direction along which the pressure may be applied. Local Z indicates that the pressure is applied normal to the element in the local Z direction. Enter the pressure intensity F1 at the lowest local coordinate location (start) and the intensity F2 at the highest local coordinate location (end), Start and End are defined basd on the positive direction of the local X-axis or local Y-axis. Variation along element – Define the direction in which the pressure varies as either the local X ot Y direction or Choose the joint option, which is discussed next. Joint – Check the joint option to apply different value of pressure at different nodes of the plate element. When checked, the dialog box will change as shown below. Apply different values of pressure in the edit boxes for the different nodes. Hydrostatic: To model loads due to hydrostatic pressure on one or more adjacent elements, select the Hydrostatic tab. The hydorstatic load is converted to Trapezoidal
loads on the elements. The load is applied over the entire area of the element. The data items are explained below:
Force – Enter the value of the load at the minimum and maximum global axis in current units. For example, to model a retaining wall with soil pressure, W1 is the force at the bottom of the wall and W2 is the force at the top of the wall. Interpolate along Global Axis – Specify the global axis (X, Y or Z) along which the load vary from W1 to W2. For example, the load would vary along the Y – axis on a vertical retaining wall. Select Plate(s) – Unlike the load definition options, we must select plate(s) for this option to became active. Click on this button to select plate(s). Click on the Select Plates button. A dialog box will appear. Select all the plates of a wall on which we wish to apply hydrostatic load. Click on Done. The hydrostatic dialog box will re-appear. Direction of pressure – Specify the direction of design pressure as Local Z axis or global axes (GX, GY or GZ) and click on Add. This will assign a linearly varying hydrostatic load on all the selected elements. Element Joint Load: To specify a varying pressure at each joint on a plate, select the Element Joint Load option. The data items are explained below.
Joint Load Data – Choose Three Noded Facet / Four Noded Facet depending on whether the plate element is 3 noded 4 noded. Direction – The load may be applied along the local Z – axis or along one of the global X, Y or Z – axis (GX, GY, GZ) Add – After defining a load, click the Add button to add this under current load case in the Loads dialog box.
3.Wind Load Generation The wind load generation is a utility, which takes place as an input wind pressure and height ranges over which these pressures act and generates nodal point and member loads. This facility is available for two types of structures: 1. Panel type or closed structures. 2. Open structures. Closest structures are ones like where non-structural entities like glass facade, aluminium sheets, timber panels or non-load bearing walls act as an obstruction to the wind. If these entities are n and of included in the structural mode, the load generated because of wind blowing against them needs to be computed. Therefore, the steps involved in load generation for such structure are 1. Identify the panels – regions circumscribed by members so that a polygonal closed area is formed. The area may also be formed between the ground level along one edge and members along other. 2. Calculate the panel area and multiple it by wind pressure. 3. Convert the resulting force into nodal point loads. Plates and solids are not considered in the calculation of the panel area. Openings within the panels may be modeled with the help of exposure factors. An exposure factors is associated with each joint of the panel can be reduced or increased. Open structures are those like transmission towers, in which the region between members is “Open” allowing the wind to blow through it. The procedure for load generation for open structures is 1. Calculate the exposed area of the individual members of the model. 2. Multiply that exposed area by the wind pressure to arrive at the force and apply the force on the individual members as a uniformly distributed load. It is assumed that all members of the structures within the specified Rangers are
subjected to the pressure and hence, they will all receive the load. The concept of members on the Windward side shielding the members in the inside regions of their structures does not exist for open structures. At a large structure may consist of hundreds of panel and members, the user with the help of this facility can avoid a considerable amount of work in calculating the loads. The wind load menu option allows the user to define the parameters for automatic generation of wind loads on the structure.
STAAD.Pro V8i is now capable of generating the wind pressure profile for a structure in accordance with the ASCE-7-95 as well as the ASCE-7-02 codes. The pressure profile is the table of values of wind intensity versus height above ground. The calculated pressure may then be applied on the structure to compute loads on the member using the in-built program‟s wind load generation algorithm for the closed as well as open-lattice type structures. When the wind load B&B of my menu option is selected, the new wind type dialog box appears, as shown below.
Enter the „Type No.‟ which denotes the number by which the wind load type will be identified. Multiple wind types can be created in the same model. Click on the Add button within this dialogue box and then click on close.
The newly created TYPE 1 wind definition will appear underneath wind in the Load dialogue.
Select the TYPE 1 name in the tree control and click on the Add button. The dialogue box shown below will prompt for the pressure profile for this wind definition.
As we said earlier, the pressure profile is the table of wind intensity versus height above ground. If we know that, that information can be typed into the box above. To calculate the wind intensity, use the following formula from IS 875-Part 3. Vz = Vb k1 k2 k3 and pz = 0.6 Vz2 where, Vz = Design wind speed at any height Vb = Base wind speed. k1 = probability factor.
k = terrain, height and structure size factor. k3 and = topography factor. pz = design wind pressure. Exposure: The exposure tab is used to modify the influence area of wind load associated with particular joints in the structure. By default, the exposure factor is 1.0, thus the wind force is applied on the full influence area associated the joints. Click on Add to add this load under the current load case in the load dialogue box.
4.Assigning Wind Load This tab allows the user to apply previously created wind load type on the structures through the means of a load case. If the model already contains previously defined wind load cases, a dialogue box resembling the one shown will appear.
Select type: Choose a previously defined wind load type from the drop down list. Direction: Specify the global direction in which the wind load is to be generated by clicking the X, Z, -X or –Z radio button. When wind is generated in X direction, the wind load is applied on the near side and when –X is chosen the load is applied on the far side. Generation in Z or –Z also works the same way. Factor: Specify the factor to multiply the calculated wind loads. Open structure: By default, the load generation is based on the assumption that the region between members is covered by panels. To generate loads on open structures like highway signs or transmission towers, switch on this box. The members are selected and X is used and the factor is positive, then the exposed surface facing in the –X direction will be loaded in the positive X direction. If X and a negative factor, then the exposed surface facing in the X direction will be loaded in the negative x direction. If –X is entered and a positive factor, then the exposed surfaces facing in the +X direction will be loaded the positive X direction.
Chapter- 5: 1. Analysis 2. Concrete Design 3. Time History Analysis Analysis STAAD.Pro V8i offers STAAD engine for general purposes structural analysis and design. The modelling mode of STAAD environment is used to prepare structural input data. After the analysis is performed, used the menu option File→ View→ Output File→ STAAD Output to view the output files. The STAAD Analysis engine perform analysis and design simultaneously. However, to carry out the design, the design parameters too must be specified along with the geometry, properties, etc. Before you perform the analysis. Also, note that you can
change the design code to be followed for design and the code check before performing the analysis/design. Perform analysis: To do the analysis must be need to add the command from Commands→ Analysis→ Perform analysis…
This allowed the user to specify the instructions for the type of analysis to be performed using STAAD engine. In addition, this command may be used to print various analysisrelated data such as load information, statics check information, mode shapes etc. The analysis menu offers several sub menu options. When you select one of the analysis commands, you may specify the analysis-related data to be printed in the STAAD output (.ANL) file by selecting the print option radio buttons, explained below: Load data: print all the load data. Statics check: provides summation of the applied load and support reaction as well as summation of moment of load and reactions taken around the origin. Statics load: print everything that statics check does and summation of all internal and external forces at each joint. Mode shapes: print mode shapes values at the joints or are calculated mode shapes. Both: this option is equivalent to the load data plus statics check option. All: this option is equivalent to load data plus statics data. Run Analysis: The Analysis is performed under the commands under the analyse menu in the Modelling Mode. Select the Run Analysis option to perform Analysis/Design.
The Analysis Status dialog box appears:
This dialog box displays the status of the analysis process. If an error occurs during the analysis, the above dialog box displays the error message. View Output File: it will invoke the STAAD viewer with the analysis results presented in a textual format. Go to Post Processing Mode: it will take you to the STAAD.Pro Post processor where you can graphically. Stay in Modeling Mode: it will keep you in Modeling environment. During the analysis, an output file is generated. This file may contain selected input data items, results and error messages. To include a report of the input data items in the output file, use the menu options under Commands | Pre Analysis Print. The generated output file may be viewed using the menu option File | View | Output File | STAAD Output. Any errors that occur during the analysis process may be viewed using the menu option File→ View→ Output File.
Concrete Design STAAD has the capabilities of performing concrete design on limit state method of IS 456 (2000). Beam Design: Beams are designed for flexure, shear and torsion. If required the effect the axial force may be considered. For all these forces, all active beam loadings are pre-scanned to identify the critical load cases at different section of the beams. Column Design: Columns are designed for axial forces and biaxial moments at the ends. All active load cases are tested to calculate reinforcement. The loading which yield maximum reinforcement is called the critical load. Column design is done for square, rectangular and circular sections. By default, square and rectangular column and designed with reinforcement distributed on each side equally for the sections under uni-axial moment. Design Parameters: The program contains several parameters which are needed to perform design as per IS 456 (2000). Default parameter values have been selected that they are frequently used numbers for conventional design parameters. These values may be changes to suit the particular design performed. Performing Concrete Design: 1. Click Commands→ Design→ Concrete Design. 2. Now the user can specify the design parameters for the structure. 3. Concrete Design dialog box appears.
4. Click the Select Parameters button. Now you can select the desired parameters for the concrete design.
5. Click Ok. Then Click Define Parameters button, now you can define the parameter
Important Parameters To Be defined Are Given Below: Parameter Name FC FYMAIN FYSEC MAXMAIN MAXSEC MINMAIN MINSEC
Default Value Description 2 25000 KN/mm Concrete yield strength. 415000 KN/mm2 Yield stress for main reinforcing steel. 415000 KN/mm2 Yield stress for secondary reinforcing steel. 60 mm Maximum main reinforcement bar size. 12 mm Maximum secondary reinforcement bar size. 10mm Minimum main reinforcement bar size. 8 mm Minimum secondary reinforcement bar size.
6. Now Click Commands button, Design Commands dialog box appears.
7. Click Add button to add the parameters, then assign the commands to the respective members.
8. Assign the DESIGN BEAM to the members parallel to X and Z direction.
Click Select→ Beam Parallel To X. Click Select→ Beam Parallel To Z.
9. Assign the DESIGN COLUMN to the members parallel to Y direction.
Click Select→ Beam Parallel To Y.
10. Then Run Analysis, the result provide the suitable concrete design for the structure. NOTE: After the analysis, double – click the member of the structure, it show the concrete design, if the concrete design of the element is missing, then it is said to unsafe.
Time History Analysis Time history analysis is an advanced method of dynamic analysis. It has an ability to incorporate harmonic forcing functions that can be described by sinusoidal curves with a specified arrival time, frequency, amplitude and duration. Define Time History Dialog: Used to define the Forcing Function of a time varying load. Click Commands→ Loading→ Definitions→ Time History→ Forcing Functions is selected or The Add… button is clicked in the Load & Definition dialog found on the General | Load & Definition page.
Integration Time Step: Solution time step used in the step-by-step integration of the uncoupled equations. Type: This refers to the number of the type of functions. Loading type: Select the Acceleration, Force or Moment option to define the type of functions being input. Save: Select this option to create an external file containing the history of displacements of every node of the structure at every time step.
Function Options: Define Time VS Used to specify a time history forcing function, where the loading type is that selected above. Specify the values Time and corresponding Force or Acceleration. The time history function is plotted on the bottom of the dialog as data pairs are entered. Harmonic:
Curve Shape: Specify if the harmonic function is a SINE or COSINE curve. Frequency or RPM: Choose Frequency and enter circular frequency in cycles per second or RPM and enter revolutions per minute. Amplitude: Max. Amplitude forcing function in current units.
Phase: Phase angle in degrees. Cycles: No.of cycles of loading. Step of Sub Div: Choose the step option to time step of loading SubDiv to sub divide a 1/4 cycle into this many integer time steps. Spectrum: Select this Function Option to provide spectrum parameters for your time history loading. Time History Parameters Dialog:
Time Step: Specify a solution time step to be used in the step-by-step integration of the uncoupled equations. Damping: The following options are available for specifying damping: Damping-this is to be used for specifying a single model damping ratio which will be applied to all mode. The default value is 0.05.
CDAMP – if a damping ratio has already been specified under CONSTANTS based on the type of material in the structure, the value may be used directly in time history analysis. Check this option for that purpose. MDAMP – we wish to utilise individual damping ratios for individual modes, that is achieved through the means of the MDAMP option. The first step to doing this is the specification of those individual damping ratios, as explained under section 5.26 .3 of the STAAD technical reference manual and is done graphically from the commanddefine damping menu. If this first step has been completed, the instruction to utilise MDAMP done by selecting this option shown above. Arrival time: specify values of possible arrival times of the various dynamic load types. The arrival time is the time at which the load type begins to act at a joint or at the base of the structure. The same load may have different arrival times for different joint and hence all these values must be specified here. The arrival time and time force pairs for the load types are used to create the load vector needed for each time step of the analysis.
Chapter- 6: 1. Introduction to FEM 2. Plate 3. Surface 4. Meshing Introduction to FEM The Finite Element Method (FEM) is a numerical technique for finding approximate solution of partial differentially equation (PDE) as well as integral equation. The finite element method is a good choice for solving partial differential equations more complicated the domains, when the domains changes, when the desired precision varies over the entire domains, or when the solution lacks smoothness. The final element method originated from the need for solving complex elasticity and structural analysis in civil and aeronautical engineering. Its development can be traced back to the work by Alexander Hrennikoff and Richard Courant. While the approaches used by the pioneers are dramatically different, they share one essential characteristic: mesh discretization of continuous domains into a set of the sub-domains, usually called elements.
The development of final element that began in the earnest in the middle to late 1950s for airframe and structural analysis and gathered momentum at the University of stuttgart through the work of Jhon Argyris and at Berkeley through the work of Ray W. Clough in the 1960s for use in civil engineering. By late 1950s, the key concept of stiffness matrix and element software NASTRAN in 1965. The method was provided with rigourous mathematical foundation in 1970 with the publication of strang and Fix‟s‟An analysis of the finite element method has since been generalised into a branch applied mathematics for numerical modelling of physical system in a wide variety of engineering disciplines.
Plate Add Plate: This option allows you to Triangular or Quadrilateral plate elements by connecting existing nodes. To add quadrilateral plate, select Quad from the sub-menu. For triangular plates, select Triangle from the sub-menu . The cursor changes to Quad plate or Triangular Plate shapes. To create new elements, simply click on the existing nodes in the right sequence. A rubber banded area shows the boundary of the plate being generated. Set New Plate Attribute: Similar to the “ Set New Member Attribute” command in which the user is in can define the property, material and releases to each new plate element as it is created, has been introduced.
In order to define the attributes for plate element before they are created, go to Geometry→ Add Plate → Set New Plate Attributes from the main menu.
A dialogue box will prompt for various attributes of the plate to be pre-defined. A summary of a specific attributes are defined in the table below.
Button Create New Property
Function Prompts the plate thickness dialogue box that the thickness of the plate at each of the common node can be defined. Defined the various material properties of the plate including poison ratio, modulus of elasticity, shear modulus, etc. Define the degree of freedom to be released at each node of the plate to the plane stress no in plane rotation or no stiffness.
Create New Material
Create New Release
Multiple properties, releases and materials can be created and saved for future use. To choose from various pre-defined types, simply select the appropriate definition using the “Select Property”, “Select Material” or the “Plate Release” drop-down boxes. For the program to recognize the pre-defined attributes, the “Assign these attributes while creating a new plates” check box must be checked. Any new plate element created from here on will now possess these attributes. How to Sketch Plates: 1. Click the plate icon
.
2. Now automatically beam cursor will change into plate cursor and nodes in the structure are visible.
3. Plate can drawn only clicking the four node points. 4. After placing the plate, click Commands menu→ Member Property→ Plate Thickness. Now the Properties Whole Structure dialog box appears.
5. Click Thickness button, now the Plate Element/ Surface Property dialog box appears, where you add different types of member properties of plate and surface element.
6. Type respective value of thickness for the plate element. Click Add button. 7. Now click Select menu→ Plate cursor. 8. Now select the plates and select the radio button Assign to selected plates and click Assign button.
9. Now open the 3D rendering page. You can see the Plate with defined thickness.
Surface Add Surface: Adding surface is similar to the adding plates where the plates can be placed by clicking only 4 node points while the surface can be placed by clicking more than 4 node points. Finally you have to click the node point where you start placing the surface. How to Add surface in the structure: 1. Click Add Surface icon or Click Geometry menu→ Add Surface. 2. Now the beam cursor changes into surface cursor. 3. Place the surface by clicking the node points and finally click the node point where begin.
4. As usual define the property for surface. Type the respective thickness value for surface member.
5. Now Assign the member property to the surface by selecting the surfaces using the surface cursor.
6. Now Open 3d Rendering View.
Meshing Meshing is the process of creating a finite element mesh over the respective member. The nodes that form the corners of the polygon representing the super – element must already exit on the drawing before the facility can be availed. They can be selected in a sequence and the process launched. Meshing can be done over the plate and surface they can be classified into two are 1. Plate mesh. 2. Surface mesh.
Plate Meshing: This is an utility meant for taking an existing plate element and subdividing into a set of smaller elements. Consequently, a plate element must already exist on the drawing in order for this facility to be enabled. Using the Plate Cursor, Click the right mouse button on the element and select Generate Mesh. Alternatively select the Geometry menu→ Generate Plate Mesh. If the element being meshed is triangular, the polygonal mesh feature described in the previous section will automatically become activated. If the element is quadrilateral, the user have to choose between polygonal and quadrilateral meshing. 1. Select the plate element, right click in the selected element. 2. Click Generate Plate Meshing. Now the Meshing type dialog box appears. 3. Choose the type of meshing, Click Polygonal Meshing and click OK
4. Now the Define Mesh Region dialog box appears, user have to define the boundary of the meshing surface. Click OK button.
5. Now the meshing surface is visible, then apply the plate load and proceed analysis.
Polygonal Meshing.
Quadrilateral Meshing.
Surface Meshing: Surface meshing is similar to the process of plate meshing. Same procedure is followed for the surface meshing. Click Geometry menu→ Generate Plate Mesh. Now select the surface element and provide respective boundary condition. Click OK button. Now you get the surface mesh.
Chapter- 7: (Slabs) 1. Desgin Of Slab 2. Design Of One Way Slab 3. Design Of Two Way Slab 4. DesignOf Staircase 5. Design of Bridge using STAAD.Beava
Slab Design Slabs are the important structural component where the pre-stressing is applied. With increase in the demand for fast track, economical and efficient construction, prestressed slabs are becoming popular. The slabs are presented in two groups are
One way slabs Two way slabs
A slab is pre-stressed for the following benefits. 1. Increased span-to-depth ratio Typical values of span-to-depth ratios in slabs are given below.
Non-pre-stressed slab 28:1 Prestressed slab 45:1
2. Reduction in self weight. 3. Section remains uncracked under service loads which increases durability. 4. Quick release of formwork which help for fast construction. 5. Reduction in fabrication of reinforcement. 6. More flexibility in accommodating late design changes. Design of One – Way Slab One – Way Slab: Rectangular slabs can be divided into two groups based on the support condition and length-to-breadth ratios. The one-way are identified as follows: 1. When a rectangular slab is supported on all the four edges and length-to-breadth (L/B) ratio equal to or greater than two, the slab is considered to be a one-wayslab. The slab spans predominantly in the direction parallel to the shorter edge. 2. when a rectangular slab is supported only on two opposite edges, it is a one-way slab spanning in the direction perpendicular to the edges. Precast planks fall in this group. A slab in a framed building can be a one-way slab depending upon its length-to-breadth ratio. A one-way is designed for spanning direction only. For the transverse direction, a minimum amount of reinforcement is provided. A slab under flexural behavior like a beam. One-way slabs are analysed and designed for spanning direction similar to the rectangular beams. A slab of uniform thickness subjected to a bending moment uniformly distributed over its width. Although a one meter wide strip of the slab is considered as a beam for the analysis and design for flexural strength, there is a difference between the beam and slab as follows. When a beam bends, the portion of the section above the neutral axis is under compression and hence subjected to a lateral condition. Hence after bending, the cross-section, will strictly not be a rectangular, but nearly a trapezoidal. In the case of a one-way slab, for a design strip, such lateral displacements and strains are prevented by the remainder of the slab on either side i.e it retains the rectangular shape after even after bending. The final design involves the checking of the stresses in concrete at transfer and under service loads with respect to the allowable stresses. The allowable stresses depend on the type of slab. During the design, the reinforced bars are usually spaced uniformly over the width of the slab.
Design Steps In STAAD.Pro V8i: 1. Create a member to represent the slab. 2. Assign the suitable support to both ends. 3. Assign the Cross section properties. 4. Assign the load as follows
Dead Load.
1. Selfweight 2. Uniformly Distributed Load to represent the floor finish
Live Load
1. Uniform Distributed Load
Combination Load as per IS 456.
Design Of Two – Way Slab If a concrete slab is supported by a beams along all four edges and reinforced with steel bars arranged perpendicularly, it is known as two-way slab. In other words, slab panels that deform with significant curvature in two orthogonal directions must be designed as two-way slabs, with the principle reinforcement placed in the two directions. In general, twisting moments develop in addition to bending moments in a two-way slab element, except when the element is oriented along the principal curvatures. These twisting moments can become significant at points along the slab diagonals Wall Supported VS Beam Supported Slabs: The distributed load on the typical tw0-way slab is transmitted partly along the short to the long edge supports and partly along the long span to the short span supports. In wall-supported panels, these portions of the load are transmitted by the respective wall supports directly to their foundations vertically below. The design considerations of deflection control criteria.
In beam-supported panels, the portion of the load transmitted by the slab in any one direction is in turn transmitted by the beam in the perpendicular direction to the two supporting columns. Slabs supported by beams behave differently, when compared to slabs supported on walls, because of the influence of the following factors.
Deflections in the supporting beams. Torsion in the supporting beams. Displacements in the supporting beams.
Design Steps in STAAD.Pro: 1. Create the frame model of the structure. 2. Use the Parametric Modelling to find the optimisation size of the elements. 3. Assign the supports. 4. Assign the Primary and Combination Loads. 5. Do the analysis and design.
Design Of Staircase Staircase is a vital element of a building providing entree to different floors and roof of the building. It comprises of a flight of steps and one or more midway landing slabs in the middle of the floor levels. Architectural thoughts including aesthetics, structural feasibility and functional desires are major characteristics to select a specific type of the staircase. Other persuading parameters for the selection of lighting, ventilation, comfort, accessibility, space etc. The common terminologies used in staircase are:
Tread: The horizontal top portion of a step where foot rests is called as tread. The dimension varies from 270 mm for residential buildings and factories to 300 mm for public buildings where large number of persons use the staircase. Riser: The vertical distance between two successive steps is called as riser. The dimension of the riser varies from 150 mm for public buildings to 190 mm for residential buildings and factories. Waist: The thickness of the waist-slab on which steps are made is called as waist. The thickness of the waist is the minimum thickness perpendicular to the soffit of the staircase. The steps of the staircase resting on waist-slab can be made of bricks or concrete.
Design Procedure In STAAD.Pro: Design the waist-slab type of the staircase
Finish Load = 1Kn/m2 Live Load = 5Kn/m2 Riser = 160mm Tread = 270mm Use M25 grade concrete and Fe 415 steel.
STAAD.Beava The general philosophy governing the design of bridges is that, subject to set of loading rules and constraints, the worst effects due to load application should be established and designed. The process of load application can be complex as governing rules can impose inter-dependent parameter such as loaded length on a lane, lane factors and load intensity. To obtain the maximum design effects, engineers have to try many loading situations on a trial and error basis. This leads to the generation of many live load application instances and a large volume of output data that has to be combined with dead load effects as well. In view of the above, a computer program has been developed to minimize the load application process while complying with national code requirements. Users can avoid trial and error approach and eliminate any possible errors arising from inaccuracies associated with it. This program is based on the use of influence surface for a given effect on a bridge deck relates its value to movement of a unit load over the area of interest. The influence surface is a three dimensional form of an influence line for a single member. STAAD.Pro V8i will automatically generates influence surfaces for effects such as bending moments for elements, deflection in all degree of freedom of nodes and support reaction. The engineer will then instruct the program to utilise the relevant influence surfaces and with due regards to code requirements, optimise load positions to obtain the maximum desired effects. Once the influence surfaces have been generated, they are saved and can be used for any further investigation that may be requires. This will remain valid as long as the user has not altered the structural model. Changes to the structural model can alter the pattern of the influence surfaces and the user must ensure that a further run takes place before any further processing. The Engineer‟s knowledge and judgement is critical in deciding which effects are required and at which position to obtain them. This is where users can save lot of processing time and can ensure critical positions are not missed. The current versions of Bridge Engineering Automated Vehicle Application (B.E.A.V.A) supports the UK BS5400 part2, American AASHTO and Indian IRC 6:2000 standards.
All the relevant code instructions for loading definitions and traffic lane calculations are incoporated in BEAVA and in case where vehicle axle arrangements are not standard, it is possible to define a vehicle and save it in library for use it in analysis. BEAVA is fully integrated in STAAD.Pro and utilises the GUI for all input data. The user defines the width of the carriageway as straight or curved parallel lines, BEAVA then automatically calculates the following in accordance with selected code:
Number of Notional Lanes Influence lines along the center line of notional lanes. Loaded length along the lanes. Critical location of uniformly distributed load. Critical location of knife edge load. Maximum effect value. Associates effects values.
Loading arrangements for the effects requested can be displayed on the model and for every loading arrangements are produced, the user can instruct the program to generate a STAAD.Pro load case. The added live load cases can be combined with dead loads i in the normal way of STAAD.Pro load combination generation. The final model can then analsed in STAAD.Pro and then post-processed. To avoid inefficient use of the program, it is recommended that the following steps be taken in the order suggested.
Create the structural model including member properties and support conditions.
From the Mode menu select Bridge Deck Pre-processor; note that if your security device is not programmed for this module you will not be able to proceed. The menu bar has been modified to show Deck and Vehicle. Select the elements/members that define the deck area of model. From Deck menu, select Create Deck to define the deck. From Deck menu, select Influence Surface generator. This will start analysis procedure to create the influence surfaces. From Deck menu, select Define Carriageway and define either a straight or a curved carriageway. From Deck menu select Load Generator. Proceed to select the required input, on completion, select OK. The loading program is now engaged and will calculate all the requires loading arrangements that lead to max/min effects you have request. On completion, a text file will be displayed on the screen containing the loading arrangements, which you can now display graphically. For each effect requested display the loading arrangements and examine the correctness. For each effect requested, select Create Loading in STAAD Model from Deck menu. After all load cases have created, from Mode menu select Modelling and return to carry on with other load generates and combinations. Proceed with analysis and post processing in the usual way.
How To Design A Bridge By Using Bridge Deck Preprocessor Bridge Deck Preprocessor By Using STAAD.Beava
Design Procedure For Bridge Deck Preprocessor: 1. Create the bridge model which comprises of Columns, Beams and Girders. 2. Assign the Pinned support to the columns.
3. Use the Geometry menu→ Generate Surface Meshing to create the bridge deck as follows.
Mesh type = Quadrilateral
Number of division along length = 75 Number of division along width = 16
4. Now type the values and click Apply. Model appears like as shown below.
5. Assign the Member properties and Specifications for the elements
Column = Circular Cross Section with 1 meter dia in concrete. Beam parallel the X and Z direction = Rectangular Cross Section with 0.5 m x 0.5 m in concrete. Plate Elements = 0.3 m Thickness in concrete. Member Offset = Decide the suitable member offsets as per the cross section dimensions.
6. Add a primary load case with Dead Load type and assign the Selfweight for all the elements.
7. Perform Analysis and Run Analysis. Note the node id, which has the maximum displacement due to load. 8. Click Mode menu→ Bridge Deck Preprocessor.
9. Select all the plates.
10. Click Deck menu→ Create Deck, name the deck.
11. Click the Loading menu→ Run Influence Generator. It takes sometimes to complete the analysis over the plates elements.
11. Click the Loading menu→ Influence Diagram… Check the diagram for all the elements.
12. Click Deck menu→ Define Roadway.
13. Click New button. Define Roadway dialog box appears.
Click Add Lane Left Orientation = 90 Length = 75 Origin = 2 Width = 4 Add the Curb on the lane side by side
14. Click Ok. Now you can get the model with the corresponding lanes.
15. Click Vehicle menu→ Vehicle Database. Now Vehicle Database dialog box appears.
16. Select the suitable IRC Vehicle for your design. Click Ok. 17. Click Loading menu→ Run Load Generator…
Limit = Ultimate Design Code = IRC Chapter 3 Loading Type = Class 70R Loading Enter the Node Displacement Values
18. Click Ok. Now automatically it will generate result values in notepad.
19. Verify and close the notepad.
20. Right click in the window, select the Structures Diagrams… Select the Results values and click OK.
21. Click Loading→ Create Loading in STAAD Model. Now the following dialog box appears
22. Now Run Analysis and then move to post processing. In Post Processing window, click the Beam tab→ Forces.
3. Now you can provide the concrete design over the model.
Chapter- 9: (Steel) 1. Design Of Steel Structures 2. Member Specification Table Member Property
Design Of Steel Structures STAAD.Pro V8i comprises an extensive set of accommodations for designing steel structural members as individual components of an analyzed structure. The member design services provide the user with the skill to carry out a number of different design procedures. These services may be used selectively in accord with the necessities of the design problem. The procedures to perform a design are:
Identify the members and the load cases to be considered in the design.
Identify whether to perform code checking or member selection.
Identify design parameter values, if different from the default values.
Presently, STAAD.Pro V8i supports steel design of wide flange, S shape, M shape, HP shapes, T shape, I shape, angle, double angle, channel, double channel, pipes, tubes, beams with cover plate and composite beams.
Design Process follows the following design checks 1. Slenderness 2. Section Classification 3. Tension 4. Compression 5. Shear 6. Bending 7. Combined Interaction Check when a design is performed, the output file reports the maximum ratio from all the above mentioned checks. Indian Steel Design IS 800:2007 Parameters
Parameter Name
FYLD KY
250 MPA 1.0 KZ
LY LZ MAIN
NSF RATIO TMAIN TRACK CMYCMZ
DFF
DJ1
DJ2
Default Value
Description
Yield strength of steel. K value in local y-axis. Usually, this is minor axis. 1.0 K value in local z-axis. Usually, this is major axis. Member Length Length in local y-axis to calculate slenderness ratio. Member Length Same as above except in local zaxis (major). 180 Allowable Kl/r for slenderness calculations for compression members. 1.0 Net section factor for tension members. 1.0 Permissible ratio of the actual to allowable stresses 400 Allowable Kl/r for slenderness calculations for tension members. 0 0=Minimum detail1=intermediate detail level2=maximum detail 0.85 for sidesway and Cm value in local y & z axes calculated for no sidesway None “Deflection Length” / Max. (Mandatory for allowable local deflection deflection check) Start Joint Joint No. denoting starting point of member for calculation of “Deflection Length” End Joint of member Joint No. denoting end point for calculation of “Deflection Length”
Member Specification Cable: This command may be used to model a specified set of members as CABLE members. The CABLE members, in addition to elastic axial deformation, are also capable of accommodating the stiffness of initial tension due to static loads. The Cable menu option under the commands menu→ Member Specification allows the user to define cable members. When you select the Cable menu option, the Member Specification dialog box appears, as shown below:
Provide either the Initial TENSION in the cable as o force, or the Unstressed LENGTH of the cable of the cable member. Click the Add button to add this specification to the structure or click Assign to assign the specification to selected members as well as add this specification to the structure. The TENSION specified in the CABLE member is applied on the structure as an external load as well as is used to modify the stiffness of the member. The tension value must be positive to be treated as cable; otherwise, it is a truss. If TENSION or the value is omitted a minimum tension will be used. This is truss member but not a tension only member unless you also include this member in a MEMBER TENSION input. Note also that Member releases are not allowed. The tension is a preload and will not be the final tension in the cable after the deformation due to this preload.
Tension/Compression: This command may be used to designate certain member as Tension only or compression only members. The Tension Only / Compression Only menu option in the Member Specifications menu allows the user to define tension only or compression only members. These members are capable of carrying tensile forces only.
Click the Add button to add this specification to the structure or click Assign to assign the specification to selected members as well as add this specification to the structure. MEMBER TENSION 0 This command switches off ALL tension/compression only specification for load cases, which are specified subsequent to this command, usually entered after a CHANGE command. There is no list associated with this command. Hence, for any further primary load cases, the tension/compression only attributed is disabled for ALL members. Tension only member are truss/cable members that are capable of carrying tensile forces only. Thus they are automatically inactivated for load cases that create compression in them. Compression only members that are capable of carrying compressive forces only. Thus, they are automatically inactivated for load cases that
create tension in them. Member Releases are not allowed on members with this attribute. The Procedure for analysis of Tension only or Compression only members requires iteration for every load cases and therefore may be moderately involved. The user may also consider using the INACTIVE specification if the solution time becomes unacceptably high. If a CHANGE command is used, then the SET NL command must be used to convey to STAAD that multiple analyses and multiple structural conditions are involved.
Table Member Property Click Commands→ Member Property→ Steel Table
This allows the user to choose steel sections from the available in-built steel tables for different countries. The Steel Table option provides a sub-menu that includes available countries steel table types. Select the country from this sub-menu. Please note that the Properties dialog box also opens simultaneously letting us utilize some of the other options available from the dialog box. After choosing the country, the Steel Table dialog box appears as shown below:
Select the type of section by clicking on the appropriate tab and then select the specific section from the list box. Please note that the type of steel section available for selection will vary depending on the selected country. In addiction, depending on the type of section selected, additional properties may be specified. Click Add button to add this property to the structure or click Assign to assign the property to the selected members as well as add this property to the structure.
Click on the View Table button to display all the available dimensions in the active database for the sectional cross-section. This option displays all member properties for the current country steel table in a dialog box and provides the feature to customize steel section database.
User is provided with the following two options in the dialog box:
Select Single Section – Where user can select the section for the structural member Selection Sections to Project Database – Where user can select/deselect sections from the Steel Table for the specified project.
Chapter- 10: (Seismic Loads Worked Examples) 1. Calculate Natural Frequency of a Buiding By Response Spectrum Analysis 2. Calculate Natural Frequency of a Building By Rayleigh Method 3. Calculate Natural Frequency of a Building By Modal Shape Calculate Natural Frequency of a Building By Response Spectrum Analysis
Design Procedure For Response Spectrum Analysis: 1. Open STAAD.Pro V8i.
2. Click New Project and set the units as Kilo Newton & Meter. 3. In STAAD.Pro, open Run structure wizard in Geometry menu→ Run Structure Wizard. 4. Change the Model Type into Frame Model and select Bay Frame, now the Select Parameter dialog appears. 5.Set the parameter of the structure as shown below.
6. Click File menu→ Merge Model with STAAD.Pro Model and place the model at origin. 7. Now assign Fixed support to the structure.
8. Assign the Member Property for column as YD=0.6 m & ZD= 0.6 m and for beam YD= 0.75 m & ZD= 0.6 m.
9. Now you can see the model in 3D Rendering.
10. Next Loading process, Click Commands→ Loading→ Definitions.
11. Select Seismic Definitions and click Add button.
12. Now Add New : Seismic Definitions dialog box appears, in Type drop down box select the respective codes for design. i.e IS 1893 – 2002/2005 13. Click Generate button, now the IS 1893 Seismic Parameter dialog box appears.
Choose the zone and it factors, Response Reduction factor, Importance Factor, Type of Structure and Type of soil.
14. Click Generate button. In IS 1893 Seismic Parameter dialog box type the Damping Value as 0.05. Click Add button.
15. Now your seismic definition is added, then add other factor of seismic definition. First you have to add the basic factors.
Self Weight Factor = 1, click Add button. Floor Weights must assigned as given below and click Add button.
16. Now you are going to add the Load Case Details. 17. Load Case Type 1 ( Here you assign floor loads only in GY direction and values must be negative.)
LOAD CASE 1 YRANGE 0 42 FLOAD 3.5 YRANGE 43 45 FLOAD 2.5 YRANGE 0 45 FLOAD 1.5
18. Load Case Type 2 Response Spectrum (Here you add the self weight of the structure in positive X and Z direction and negative Y direction. Different floor load in all three global directions.)
LOAD CASE 2 SELFWEIGHT X 1 LIST ALL SELFWEIGHT Y -1 LIST ALL SELFWEIGHT Z 1 LIST ALL FLOOR LOAD YRANGE 0 42 FLOAD 3.5 GX YRANGE 0 42 FLOAD 3.5 GY YRANGE 0 42 FLOAD 3.5 GZ YRANGE 43 45 FLOAD 3.5 GX YRANGE 43 45 FLOAD 3.5 GY YRANGE 43 45 FLOAD 3.5 GZ YRANGE 0 45 FLOAD 3.5 GX YRANGE 0 45 FLOAD 3.5 GX YRANGE 0 45 FLOAD 3.5 GX
19. Now you have to assign the self weight to structure by Assign to view. 20. Then add another load item Response Spectra as shown below.
21. Then Click Commands→ Miscellaneous→ Cut Off Mode Shape…. Mode Shapes Value is 10.
22. Click Commands→ Analysis→ Perform Analysis Print All. 23. Then Run Analysis or press CTRL + F5.
24. Result Values Eigen Values: Calculated frequencies for load case.
Mode Shape Values:
Mass Participation Factor is important for analysis.
25. Deflection:
26. Click Ok button.
How To Calculate Natural Frequency By Rayleigh Method Design Procedure For Rayleigh Method: 1. Open STAAD.Pro V8i. 2. Click New Project and set the units as Kilo Newton & Meter. 3. In STAAD.Pro, open Run structure wizard in Geometry menu→ Run Structure Wizard. 4. Change the Model Type into Frame Model and select Bay Frame, now the Select Parameter dialog appears. 5.Set the parameter of the structure as shown below.
6. Click File menu→ Merge Model with STAAD.Pro Model and place the model at origin. 7. Now assign Fixed support to the structure.
8. Assign the Member Property for column as YD=0.6 m & ZD= 0.6 m and for beam YD= 0.75 m & ZD= 0.6 m, Plate Thicness = 0.15m.
9. Now you can see the model in 3D Rendering.
10. Next Loading process, Click Commands→ Loading. 11. Now the Load & Definitions dialog box opens, add the following loads:
12. Then Perform Analysis, Select All. 13. Now Run Analysis. Result you will get the Rayleigh Frequency for load case 1.
Note: Please ignore if you get any warnings. 14. Now add Load case 2: Assign the following loads
15. Again Run Analysis. Now you get the Rayleigh Frequency for load case 1 and load case 2.
16. Then check the deflection using Animation command. Provide suitable concrete design the control the deflection.
How To Calculate Natural Frequency of a Building By Modal Shape Design Procedure For Modal Shape: 1. Open STAAD.Pro V8i. 2. Click New Project and set the units as Kilo Newton & Meter. 3. In STAAD.Pro, open Run structure wizard in Geometry menu→ Run Structure Wizard. 4. Change the Model Type into Frame Model and select Bay Frame, now the Select Parameter dialog appears. 5.Set the parameter of the structure as shown below.
6. Click File menu→ Merge Model with STAAD.Pro Model and place the model at origin. 7. Now assign Fixed support to the structure.
8. Assign the Member Property for column as YD=0.6 m & ZD= 0.6 m and for beam YD= 0.75 m & ZD= 0.6 m, Plate Thickness = 0.15m.
9. Now you can see the model in 3D Rendering.
10. Click Commands→ Miscellaneous→ Cut Off Mode Shape... 11. Now the Cut Off Mode Shape dialog box appears. Enter the desired number of modes you want. Click Ok
12. Then add the following Load Cases:
13. Finally you have add the Modal Calculation command.
14. Now assign the respective loads to the elements. 15. Then Perform Analysis and Run Analysis.
16. In Result you get the Calculated Frequency of Load Case.
17. According to IS 1893, Mass Participation Factors must be atleast greater than 90.
18. Then Check the deflection using Animation command.
19. Now you have to provide the suitable concrete design to control the deflection. Note: For more info and further details watch the video. Chapter- 11: (Wind Load Intensity Worked Examples) 1. Calculate Wind Load Intensity In A Building Wind Load Intensity Calculation How to calculate wind load as per ASCE – 7 ?
Design Procedure To Calculate Wind Load Intensity: 1. Open STAAD.Pro V8i. 2. Click New Project and set the units as Kilo Newton & Meter. 3. Open the Grid and Form the following grid.
4. By using the Snap/Node Beam Add the members and select the members. 5. Now use the Translational Repeat option to build the structure.
6. Assign the respective support for the structure.
7. Assign the suitable member property for the model. For Column = 0.75 x 0.75 m For Beam: YD = 0.60; ZD = 0.40 8. Now open the structure in 3D rendering.
9. Then Wind Definition in Load Case.
10. Now click Calculate as per ASCE-7 button. Now the select respective code and type of building. Click OK
11. Wind load in calculated according the varying height of the structure. Click Close button.
12. Add the suitable factor of exposure. 13. Assign the Exposure against the structure.
14. Assign the following Load Cases.
15. Perform Analysis and Run Analysis. 16. According to the result values provide the suitable concrete design for the structure. 17. Again Run the Analysis. 18. Now you get the concrete design of the elements.
19. In Post Processing, You can get the Bending Moment and Shear Force values.
