EVALUATION OF PROFESSIONAL SOFTWARE FOR STRUCTURAL ANALYSIS AND DESIGN FOR ANOMALIES IN COMPLIANCE OF CODAL PROVISION. STAAD PRO V8i AND SAP 2000
PATEL URVI K.
FOR THE PARTIAL FULFILLMENT OF THE AWARD FOR THE DEGREE OF
MASTER OF TECHNOLOGY (CIVIL-STRUCTURAL ENGINEERING) UNDER THE GUIDANCE OF
PROF.K.N SHETH
DEPARTMENT OF CIVIL ENGINEERING FACULTY OF TECHNOLOGY DHARMSINH DESAI UNIVERSITY NADIAD-387001
ABSTRACT Due to the complexity and an irregularities of the structures, analysis becomes more and more difficult and tedious which leads the designer towards the development of the software that are capable of analyze the structure. That’s why analysis and design software’s oftware’s becomes more popular and most widely used in the design firms. There are many software’s developed during the last 2 decades. Analysis and design software’s like STAAD Pro V8i, SAP 2000, ETABS, STRUD, NISA, STRAP, MIDAS are available in the market. These different softwares are used for different types of the structures. For an instant, Staad has a very general usage and midas is very well known for its specialization in bridges. Mainly softwares like Staad Pro and Sap 2000 are accepted by almost all design practitioners and des\ign firms. STAAD.Pro is the structural engineering professional’s choice for steel, concrete, timber, aluminum, and cold-formed steel design of virtually any structure including culverts, petrochemical plants, tunnels, bridges, piles, and much more through its flexible modeling environment, advanced features, and fluent data collaboration. STAAD.Pro V8i involved in analysis and design of structures like Plants, Towers, Bridges, Buildings. STAAD.Pro V8i was developed for practicing engineers.For static, pushover, dynamic-delta, buckling or cable analysis,STAAD.Pro V8i is the industry standard. SAP2000 is general-purpose civil-engineering software ideal for the analysis and design of any type of structural system. Basic and advanced systems, ranging from 2D to 3D, of simple geometry to complex, may be modeled, analyzed, designed, and optimized using a practical and intuitive object-based modeling environment that simplifies and streamlines the engineering process. The Advanced Analytical Techniques allow for Step-by-Step Large Deformation Analysis, Multiple P-Delta, Eigen and Ritz Analyses, Cable Analysis, Tension or Compression Only Analysis, Buckling Analysis, Blast Analysis, Fast Nonlinear Analysis for Dampers, Base Isolators and Support Plasticity, Energy Methods for Drift Control and Segmental Construction Analysis. Bridge Designers can use SAP2000 Bridge Templates for generating Bridge Models, Automated Bridge Live Load Analysis and Design, Bridge Base Isolation, Bridge Construction Sequence Analysis, Large Deformation Cable Supported Bridge Analysis and Pushover Analysis. Advanced analysis - Options for nonlinear base isolators, dampers, gaps, large deflection, and plastic hinges for pushover analysis. Modal, response spectrum, linear or nonlinear time history dynamic analysis. No limit on use of springs, dampers, and other elements in dynamic analysis.
Evaluation information can be a powerful tool for a variety of engineers. Program managers can use the information make changes in to their programs that will enhance their effectiveness. Decision makers can ensure that they are fundin g effective programs. Programs that participate in evaluations will obtain objective information about their performance and how it can be improved. Evaluation can provide objective evidence that a program is effective, demonstrating positive outcomes to funding sources and the community. It
can help improve program effectiveness and can create opportunities for programs to share information with other similar programs and agencies. So, this thesis work mainly deals with the evaluation of design in the Staad pro v8i and sap 2000. Mainly R.C.C structures are designed as per the provisions of the IS 456 and a ductile detailing of R.C.C structure as per 13920 and IS 800 used for steel design. The design desi gn software’s are evaluated on the basis of their design parameters that are followed by the Indian standard code.
LITERATURE REVIEW
Sr No.
1
2
Author
AssistantProfessor,Departme nt of Civil Engineering, SHIATS (Formerly AAIDU), Allahabad- 211007, U.P.
Date of publi shed 2012
Title/publication
conclusion
Comparison of design It is found out from results of a Structure previous studies on designed using STAAD comparison of STAAD and ETABS Software results with manual calculations that STAADPro gives conservative design results which is again proved in this study by comparing the results of STAADPro, ETABS and Manual calculations of the M.TECH Student, May- Acomparative study and Modeling Department of Civil June analysis of earthquake structure in ETABS is Engineering, Faculty of 2014 resistant g+5 apartment found to be easier than building with shearwall in STAAD. Engineering and Technology, using staad.pro and etabs PRIST UNIVERSITY, 2) Assigning of software Thanjavur, Tamilnadu, India. various load cases and load combinations is faster in ETABS than in STAAD. 3) Modification of the structure and changes in any load cases ETABS is easier than in STAAD.
3
Dr. eng. Lyubomir A Zdravkov, eng. Zornitza A Mincheva mag. “Строителство”, 4,
2004
4
Manish S. Takey
2009
5
Rahul RANA1, Limin JIN2 2004 and Atila ZEKIOGLU3
Measuring Of The often the entered in Building Structures With SAP 2000 element’s Sap 2000 sections have geometrical characteristics which are so close but do not coincide completely with the characteristics of the real existing sections Seismic Response Of Steel Building With Linear Bracing System (A Software Approach) Pushover Analysis Of A 19 Story Concrete Shear Wall Building(Sap 2000)
REFERENCES 1) IS 456:2000 Plain And Reinforced Concrete Code Of Practice 2) IS 13920:1993 Ductile Detailing Of Reinforced Con crete Structures Subjected to Seismic Forces -Code Of Practice 3) IS 800:2007 General Construction in Steel 4) Staad Pro V8i Manual 5) Sap 2000 Manual 6) H.J.Shah (Design of R.C.C Structure) 7) Design Of Structure By Subramanian 8) Reinforced Concrete Design By S.N.Sinha.
PREREQUISITE TOOLS This Dissertation work required the below structural tools to be deal with.
Staad Pro V8i
Sap 2000
CHAPTER 1 INTRODUCTON A) IS 456 456 DESIGN CRITERIA 1. Control of Deflection 1.1 The vertical deflection limits may. Generally be assumed to be satisfied provided that the span to depth ratios are not greater than the values obtained as below: a) Basic values of span to effective depth ratios for spans up to 10m: Cantilever 7 Simply supported 20 Continuous 26 1.2 Slenderness Limit for Beams to Ensure Lateral Stability A simply supported or continuous beam shall be so proportioned that the clear distance between the lateral restraints does not exceed 60 b whichever is less, where d is the effective depth of the beam and b the breadth of the compression face midway between the lateral restraints. For a cantilever, the clear distance from the free end of the cantilever to the lateral restraint shall not exceed or 25 b or whichever is less. 1.3 Slenderness Limits Limits for Columns The unsupported length between end restraints shall not exceed 60 times the least lateral dimension of a column. If, in any given plane, one end of a column is unrestrained, its unsupported length, it shall not exceed . 1.4 Minimum Eccentricity All columns shall be designed for minimum eccentricity, eccentricit y, equal to the unsupported length of column. 500 plus lateral dimensions/30, dimensions/30, subject to a minimum of 20 rom. r om. Where bi-axial bi -axial bending is considered, considered, it is sufficient to ensure that eccentricity exceeds the minimum about one axis at a time. 1.5 Beams- Tension reinforcement a) Minimum reinforcement-The minimum area of tension reinforcements shall be not less than that given by the following: following: = where A = minimum area of tension reinforcement, b = breadthof breadthof beamor the breadthof breadthof the web web of ' T-beam. d = effective depth, and f, = characteristic characteristic strength of r einforcement einforcement in 2 N/mm 1.6 Maximum reinforcement
The maximum area of tension reinforcement shall not exceed 0.04 bD. Compression reinforcement The maximum area of compression reinforcement shall not exceed 0.04 bD. Compressionreinforcement in beams shall shall be enclosed enclosed by stirrups stirrups for effective effective lateral lateral restraint. restraint.
1.7 Side face reinforcement Where the depth of the web in a beam exceeds750mm,side face reinforcement shall be provided along the two faces. The total area of such reinforcement reinforce ment shall be not less than 0.1 of the web area and shall be distributed equally on two faces at a spacing not exceeding 300 111m or web thickness whichever is less. 1.8 Maximum spacing of shear reinforcement:The maximum spacing of shear reinforcement measured along the axis of the member shall not exceed 0.75 d for vertical stirrups stirrups and d for inclined stirrups at 45'’ where d is the effective depth of the section under consideration. 1n no case shall the spacing exceed 300 mm. 1.9 Minimum reinforcement Minimum shear shear reinforcement reinforcement in the form of stirrup shall be provided provided such that:
≥ cross-sectional area of stirrup leg effective in shear. - total cross-sectional Sv – Sv – stirrup stirrup spacing along length of member. Where the maximum shear stress calculated less than half the permissible value and in members of minor structural importance such as lintels. this provision need not be complied with. 1.10 distribution of torsion reinforcement a) The transverse reinforcement for torsion shall be rectanplar closed stirrups placed perpendicular to the axis of the member.the member.the spacing of the stirrups shall not the least of x1, and 300 mm.where x1 and y1 are respectively the short and long dimension of the stirrup. 1.11 longitudal reinforcement for column The cross-sectional area of longitudinal reinforcement, shall be not less 0.8 percentage nor more than 6 percentage. percentage. 1.12 The minimum number of longitudinal bar: provided in column four four in rectangular rectangular columns columns and six in circular circular columns.
1.13 The bars shall not be less than 12 mm in diameter 1.14 A reinforced concrete column having helical reinforcement shall have at list six bin of longitudinal reinforcement within the helical reinforcement. 1·15 Spacing of longitudinal bars measured along the periphery of the column shall not exceed 300mm. 1.16 In case of pedestals in which the longitudinal reinforcement is not taked in account in strength calculations, nominal longitudinal reinforcement Not less than 0.15 percent of the cross-sectional Area shall be provided. 1.17 Pitch and diameter of lateral ties J) Pitch-The pitch of transverse reinforcement reinforcement shall be not more than the least of the following distances: distances:
i) The least lateral dimension of the compression members; ii) Sixteen times the smallest diameterof the longitudinal reinforcement bar tobe tied iii) 300mm. 2) Diameter-The diameter of the polygonal links or lateral this shall be not less than one fourth of the diameter of the largest longitudinal bar. and in no case less than 16mm. 1.18 beam minimum reinforcement
Minimum reinforcement of beam is provided 0.2% . 1.19 beam maximum reinforcement
Maximum reinforcement in beam are provided 4%.
B) Is 13920 ductile ductile detailing of reinforced concrete structure subjected to seismic seismic force – code code of practice
Provisions of this code shall be adopted in all reinforced concrete structures which satisfy one of the following four conditions. Portions along the edges of a shear wall that are strengthened by longitudinal and transverse reinforcement. They tiay have the same thickness as that of the wall web. 1) The structure is located in seismic zone IV or V; 2) The structure is located in seismic zone III and has the importance factor ( I ) greater than 1.0; 3) The structure is located in seismic zone III and is an industrial structure 4) The structure is located in seismic zone III and is more than 5 storey high. Provisions of this code shall be adopted in all reinforced concrete structures which are located in seismic zone III, IV or V.’ 1.2 flexure member 6.1.1 The factored axial stress on the member – member – I under earthquake loading shall not exceed 0.1 fck.
1.3 The member shall preferably have a width-to-depth ratio of more than 0.3. 1.4 The width of the member shall not be less than 200 mm. 1.5 The depth D of the member shall be not more than l/4 of the clear span. 1.6 Longitudinal Reinforcement a) The top as well as bottom reinforcement shall consist of at least two bars throughout the member length. b) The tension tension steel ratio on any face, at any section, section, sha sha -ll- not be less than
Pmin = 0.24√ /fy where fck and fy in MPa. 1.7 The maximum steel ratio on any face at any section, shall not exceed Pmax = 0.025 1.8 The positive steel at a joint face must be at least equal to half the negative steel at that face. 1.9 The steel provided at each of the top and bottom face of the member at anv section along its length shall be at least equal to one-fourth of the maximum negative moment steel provided at the face of either joint. It may be clarified that redistribution of moments moments permitted in IS 456 :I978 ( clause 36.1 ) will be used only for vertical load moments and not for lateral load moments. 1.10 In an external joint, both the top and the bottom bars of the beam shall be provided with anchorage length, beyond the inner face of the column, equal to the development length in tension plus 10 times the bar diameter diameter minus6.2.7 Use of welded splices and mechanical mechanical the allowance allowance for 90 degree bend connections may also be made, In an internal joint, both face bars of IS 456 : 1978. However, not more more than half of the beam shall be taken continuously through the reinforcement shall be spliced at a section the column. 1. 11 Web Reinforcement
6.3.1 Web reinforcement shall consist of vertical hoops. A vertical hoop is a closed stirrup having a 13.5” hook with a 10 diameter extension ( but not < 75 mm ) at each end that is embedded in the confined core ( see Fig. 3a ). In compelling circumstances, it may also be made up of two pieces of reinforcement; a Ustirrup with a 135” hook and a 10 diameter extension (but not 75 mm ) at each end, embedded in the confined core and a crosstie ( see Fig. 3b ). A crosstie is a bar having a 135” hook with a 10 diameter extension (but not < 75 mm ) at each end. The hooks shall engage peripheral longitudinal bars. 1.12 The minimum diameter of the bar forming a hoop shall be 6 mm. However, in beams with clear span exceeding 5 m, the minimum bar diameter shall be 8 mm. 1.13 The spacing of hoops over a length of 2d at either end of a beam shall not exceed ( a ) d/4, and (b) 8 times the diameter of the smallest longitudinal bar; however, it need not be less than 100 mm ( see Fig. 5 ). The first hoop shall be at a distance not exceeding’ 50 mm from the joint face. Vertical hoops at the same spacing as above, shall also be provided over a length equal to 2d on either side of a section where flexural yielding may occur under the effect of earthquake forces. Elsewhere, the beam shall have vertical hoops at a spacing not exceeding d/2. 1.14 Longitudinal Reinforcement 1.14.1 Lap splices shall be provided only in the central half of the member length. It should be proportioned as a tension splice. Hoops shall be provided over the entire splice length at spacing not exceeding 150 mm centre to centre. Not more than 50 percent of the bars shall be spliced at one section. 1.14.2Any area of a column that extends more than 100 mm beyond the confined core due to architectural requirements, shall be detailed in the following manner. In case the contribution of this area to strength has been considered, then it will have the minimum longitudinal and transverse reinforcement as per this code, Rowever, if this area has been treated as nonstructural, the minimum reinforcement requirements shall be governed by IS 456 : 1978 provisions minimum longitudinal and transverse reinforcement, reinforcement, as per IS 456 : 1978 ( see Fig. 6 ). 1.15 Transverse Reinforcement 1.15.1 Transverse reinforcement for circular columns shall consist of spiral or circular hoops. In rectangular columns, rectangular hoops may be used. A rectangular hoop is a closed stirrup, having a 135” hook _with a 10 diamee;; extension ( but not < 75 mm ) at each that IS embedded in the confined core . 1.15.2 The parallel legs of rectangular hoops shall be spaced not more than 300 mm centre to centre. If the length of any side of the hoop exceeds 300 mm, a crosstie shall be provided ( Fig. 7B ). Alternatively, a pair of overlapping hoops may be provided within the columm ( see Fig. 7C ). The hooks shall engage peripheral longitudinal bars. 1.15.3 The spacing of hoops shall not exceed half the least lateral dimension of the column, except where special confining reinforcement is provided, as per 7.4. 1.15.4 The design shear force for columns shall be the maximum of: a) calculated factored shear force as per analysis, and b) a factored factored shear force force given given by where are moment of resistance, of opposite sign, of beams framing into the column from opposite faces h,t is the storey height. The beam moment capacity is to be calculated as per IS 456 : 1978.
and
1.16 Special confining reinforcement shall be provided over a length I, from each joint face, towards midspan, and on either side of any section, where flexural yielding may occur under the effect of earthquake forces . The length (lo* shall not be less than ( a ) larger lateral dimension dimension of the member at the section where yielding occurs, ( b ) l/6 of clear clear span of the member, and ( c ) 450 mm. The spacing of hoops used as special that confining reinforcement shall not exceed l/4 of minimum member dimension but need not be than 75 mm nor more than 100 mm.
STADD PRO EXAMPLES:Example 1
Loading – self self weight +15 kn/m udl +100 kN point load Fe-415 b=350 mm d=830 mm a) By manual calculation
= =0.2%
b) Staad pro v8i result
Bottom reinforcement
0 2-16dia
1.250 m 2-16dia
2.5m 3-16dia 3-16dia
3.750m 2-16dia
5m 2-16dia
Find a Ast from stadd pro v8i result:Ast=402.12 mm2 Pt= *100 =0.13%<0.2% Example 2 Allowable deflection deflection as per is 456: = 7* M.F
By from chart M.F=0.82
5.74
ACTUAL Actual
=8.33
Maxi
8.33<5.74 (not o.k) But stadd give a result for this beam. Section 0 0.625m Top reinf. 8-12dia 5-12dia Bottom reinf. 2-10dia 2-10dia Example 3
1.2m 3-12dia 2-10dia
1.875m 2-12dia 2-10dia
2.5m 2-12dia 2-10dia
Beam deflection The final deflection due to all load like temperature,creep,shrinkage and as cast level support of floor and other ,roof and all other horizontal member not exceed l/250.
l/350 =5000/350=25.71mm or 20 mm whichever is less=20 mm allowable deflection as per is 456 code is 20 mm but stadd pro v8i result result =105 mm deflection stadd pro v8i have does not any criteria for deflection . example 4 length should not be exceed, 60b=13.8 250b2/d=44.08 Here distance between lateral restrain are 15 which is greter than 13.8.bue also staad should not consire this criteria.
Example 5
Design column as a axially loded M-30 Fe-415 B=300mm D=400mm Ast from stadd pro v8i. Ast=8-12 dia Pt= *100 =0.75% Minimum 0.8% steel provided from column. There is no any provision for minimum reinforcement in staad pro.
