A project report on, Prepared in partial fulfillment of. Study oriented project, Course code: CE G611 Computer Aided Analysis and Design

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1 A project report on, Comparative study of simulation tools Staad V8, Etabs 2013, and Strap 2014 for seismic analysis of plan and vertical geometrically irregular building using Indian Standard Codes Prepared in partial fulfillment of Study oriented project, Course code: CE G611 Computer Aided Analysis and Design Submitted by, Mr. Mandar Ganbavale (2013H143013H) Under guidance and supervision of Dr. Chandu Parimi Assistant Professor, Department of civil engineering. Birla Institute of Technology and Science, Pilani. Hyderabad Campus. ( )

2 Comparative study of simulation tools Staad V8, Etabs 2013, and Strap 2014 for seismic analysis of plan and vertical geometrically irregular building using Indian Standard Codes ii

3 CERTIFICATE This is certified that the project entitled Comparative study of simulation tools Staad V8, Etabs 2013, and Strap 2014 for seismic analysis of plan and vertical geometrically irregular building using Indian Standard Codes Submitted by, Mr. Mandar Ganbavale (2013H143013H) In partial fulfillment of the requirements of course code CE G611 Study Oriented project, BITS Pilani, Hyderabad campus for the academic year It is the record of their own work carried out under our supervision and guidance. Dr. Chandu Parimi (Assistant professor, Department of Civil Engineering) Birla Institute of Technology and Science, Pilani. Hyderabad Campus iii

4 ACKNOWLEDGMENT Firstly, I would like to thank the curriculum of BITS, Pilani for giving me this opportunity in doing Study oriented project. I sincerely appreciate Dr. Chandu Parimi for giving me opportunity to work on this topic. I am grateful for his support and guidance that have helped me to expand our horizon of thought and expression. I am also thankful of my friends for their help in sharing the information about various aspects of this project. Mr. Mandar Ganbavale (2013H143013H) iv

5 CHAPTER 1 INTRODUCTION 1. Objectives The main purpose of this study oriented project is to detailed study the simulation tools for seismic analysis and designing of structures. Comparison of simulation tools STRAP, STAAD pro, ETABS and SAP 2000 for seismic analysis of Plan and Vertical geometrically irregular multi-storey building. 2. Vertical and Plan irregular multistory buildings According to IS 1893:2002 (Clause 7.1), there are mainly two types of irregularities, Plan Irregularity Vertical Irregularity a. Plan irregularity Plan irregularity also of five types as follows: i. Torsion Irregularity To be considered when floor diaphragms are rigid in their own plan in relation to the vertical structural elements that resist the lateral forces. Torsional irregularity to be considered to exist when the maximum storey drift, computed with design eccentricity, at one end of the structures transverse to an axis is more than 1.2 times the average of the storey drifts at the two ends of the structure. ii. Re-entrant corners - Plan configurations of a structure and its lateral force resisting system contain re-entrant corners, where both projections of the structure beyond the re-entrant corner are greater than 15 percent of its plan dimension in the given direction. iii. Diaphragm Discontinuity - Diaphragms with abrupt discontinuities or variations in stiffness, including those having cut-out or open areas greater than 50 percent of the gross enclosed diaphragm area, or changes in effective diaphragm stiffness of more than 50 percent from one storey to the next. 1

6 iv. Out-of-plane offsets - Discontinuities in a lateral force resistance path, such as out-of-plane offsets of vertical elements. v. Non-parallel Systems - The vertical elements resisting the lateral force are not parallel to or symmetric about the major orthogonal axes or the lateral force resisting elements. b. Vertical Irregularity Plan irregularity also of five types as follows: i. Stiffness Irregularity - 1. Soft Storey - A soft storey is one in which the lateral stiffness is less than 70 percent of that in the storey above or less than 80 percent of the average lateral stiffness of the three storeys above. 2. Extreme Soft Storey - A extreme soft storey is one in which the lateral stiffness is less than 60 percent of that in the storey above or less than 70 percent of the average stiffness of the three storeys above. For example, buildings on STILTS will fall under this category, ii. Mass Irregularity - Mass irregularity shall be considered to exist where the seismic weight of any storey is more than 200 percent of that of its adjacent storeys. The irregularity need not be considered in case of roofs. iii. Vertical Geometric Irregularity - Vertical geometric irregularity shall be considered to exist where the horizontal dimension of the lateral force resisting system in any storey is more than 150 percent of that in its adjacent storey. iv. In-Plane Discontinuity in vertical elements resisting lateral force - An in-plane offset of the lateral force resisting elements greater than the length of those elements. v. Discontinuity in capacity Weak storey - A weak storey is one in which the storey lateral strength is less than 80 percent of that in the storey above, the storey lateral strength is the total strength of all seismic force resisting elements sharing the storey shear in the considered direction. 2

7 CHAPTER 3 COMPUTER TOOLS 1. STRAP STRAP is one of the most comprehensive and versatile structural analysis and design software systems available on the market today. It's also the easiest to use, due to its superb graphic user interface (GUI) and context-sensitive help system. It offers the engineer a powerful but affordable tool for analysis and design of a wide range of skeletal and continuum structures such as buildings, bridges, shells, towers and more. STRAP uses graphical input for the generation of models and loads. Every drawing on the screen can be printed, imported into other documents, or (through DXF) into drawings. Complete analysis and design can be performed for any structure without ever referring to joint or beam numbers. Load combinations can be created after analysis is performed. Combinations can be changed instantly without solving the model again. STRAP comes with design modules for designing reinforced concrete, post-tensioned concrete and structural steel (hot-rolled and cold-formed). For the engineer interested in dynamic effects, STRAP also includes modules for modal analysis, seismic response spectra calculations according to many codes and time history response calculations. The learning curve to start using STRAP is practically non-existent. The program's flow is similar to the analysis and design process performed by hand. During the execution of every action the prompt line at the bottom of the screen guides us through. Combine this with the context-sensitive help. 2. STAAD Pro STAAD.Pro allows structural engineers to analyze and design virtually any type of structure through its flexible modeling environment, advanced features and fluent data collaboration. Flexible modeling is provided by a state-of-the-art graphical environment and the design supports over 70 international codes and over 20 U.S. codes in 7 languages. An array of advanced structural analysis and design features are included such as nuclear certification for 10CFR Part 50, 10CFR 21, ASME NQA , time history and push over analysis and cable (linear and non-linear) analysis. 3

8 Efficiencies are gained through the ability to maintain and streamline current workflows with fluent data collaboration. STAAD.Pro integrates with other Bentley products such as STAAD.foundation and ProSteel and OpenSTAAD is provided for integration with third party programs. Increased client base and therefore business growth can be realized in using STAAD.Pro to serve a broad spectrum of structural design projects and a global market. 3. SAP 2000 From its 3D object based graphical modeling environment to the wide variety of analysis and design options completely integrated across one powerful user interface, SAP2000 has proven to be the most integrated, productive and practical general purpose structural program on the market today. This intuitive interface allows you to create structural models rapidly and intuitively without long learning curve delays. Now you can harness the power of SAP2000 for all of your analysis and design tasks, including small day-to-day problems. Complex Models can be generated and meshed with powerful built in templates. Integrated design code features can automatically generate wind, wave, bridge, and seismic loads with comprehensive automatic steel and concrete design code checks per US, Canadian and international design standards. Advanced analytical techniques allow for step-by-step large deformation analysis, Eigen and Ritz analyses based on stiffness of nonlinear cases, catenary cable analysis, material nonlinear analysis with fiber hinges, multi-layered nonlinear shell element, buckling analysis, progressive collapse analysis, energy methods for drift control, velocity-dependent dampers, base isolators, support plasticity and nonlinear segmental construction analysis. Nonlinear analyses can be static and/or time history, with options for FNA nonlinear time history dynamic analysis and direct integration. From a simple small 2D static frame analysis to a large complex 3D nonlinear dynamic analysis, SAP2000 is the easiest, most productive solution for your structural analysis and design needs. 4. ETABS The innovative and revolutionary new ETABS is the ultimate integrated software package for the structural analysis and design of buildings. Incorporating 40 years of continuous research and development, this latest ETABS offers unmatched 3D object based modeling and visualization tools, blazingly fast linear and nonlinear analytical power, sophisticated and comprehensive design capabilities for a wide-range of materials, and insightful graphic displays, reports, and schematic drawings that allow users to quickly and easily decipher and understand analysis and design results. 4

9 From the start of design conception through the production of schematic drawings, ETABS integrates every aspect of the engineering design process. Creation of models has never been easier - intuitive drawing commands allow for the rapid generation of floor and elevation framing. CAD drawings can be converted directly into ETABS models or used as templates onto which ETABS objects may be overlaid. The state-of-the-art SAPFire 64-bit solver allows extremely large and complex models to be rapidly analyzed, and supports nonlinear modeling techniques such as construction sequencing and time effects (e.g., creep and shrinkage). Design of steel and concrete frames (with automated optimization), composite beams, composite columns, steel joists, and concrete and masonry shear walls is included, as is the capacity check for steel connections and base plates. Models may be realistically rendered, and all results can be shown directly on the structure. Comprehensive and customizable reports are available for all analysis and design output, and schematic construction drawings of framing plans, schedules, details, and cross-sections may be generated for concrete and steel structures. ETABS provides an unequaled suite of tools for structural engineers designing buildings, whether they are working on one-story industrial structures or the tallest commercial high-rises. Immensely capable, yet easy-to-use, has been the hallmark of ETABS since its introduction decades ago, and this latest release continues that tradition by providing engineers with the technologically-advanced, yet intuitive, software they require to be their most productive. 5

10 CHAPTER 3 PARAMETERS USED (GEOMETRIC AND SEISMIC) 1. Materials properties a. Steel - i. Modulus of elasticity of steel, E = 200 GPa ii. Poisson s ratio, µ = 0.3 iii. Steel density = 77 kn/m3 (7.850 kg/m3) iv. Yield strength of steel, Fy = 350 MPa v. Ultimate yield strength of steel, Fu = 450 MPa b. Concrete i. Characteristic strength of concrete, Fck = 25 Mpa ii. Density of concrete, ρ = 25 kn/m3 2. Building Parameters a. Beam and Columns - ISMB 450 b. Slab 150 mm c. Bay length 6m (in each horizontal direction) d. Storey height (3.5m) e. Supports Fixed 3. Loading Conditions a. Dead Load = 4.75kN/m2 (Self weight 3.75kN/m2 + Floor finish 1kN/m2) b. Live Load = 2kN/m2 Seismic weight c. Dead load = 1 d. Live Load = 0.25 Seismic parameters e. Code IS 1893: Seismic analysis in X1 and X3 directions. f. Method of combining mode shapes Complete quadratic combination with damping ratio 0.05 g. Zone III (0.16) h. Soil type Medium II i. Importance factor 1.5 j. Reduction factor 5 k. Time (Ta) sec 6

11 Fig. 1. Building 3D View Fig. 2. Building Plan 7

12 Fig.3. Building Front Elevation Fig.4. Building Side Elevation 8

13 CHAPTER 4 RESULTS 1. STAAD Pro a. DISPLACEMENT: 9

14 b. BENDING 10

15 c. AXIAL FORCE 11

16 2. STRAP 2014 a. Bending Moments b. Shear Forces 12

17 c. Displacement d. Modal results 13

18 e. Mode Shapes f. Seismic Data 14

19 3. ETABS a. Text File output - ETABS v9.7.0 File:MODEL-1 Units:KN-m December 2, :54 PAGE 1 A U T O S E I S M I C I N D I A N Case: EQX AUTO SEISMIC INPUT DATA Direction: X Typical Eccentricity = 5% Eccentricity Overrides: No Period Calculation: User Defined User T = Top Story: 4 Bottom Story: BASE R = 5 Z = 0.16 Soil Type = II I = 1.5 AUTO SEISMIC CALCULATION FORMULAS V = Z I Sa W / (2 R g) Sa/g = T for 0.0 <= T <= 0.1 Sa/g = 2.5 for 0.1 <= T <= 0.55 (Soil Type II) Sa/g = 1.36/T for 0.55 <= T <= 4.0 (Soil Type II) 15

20 AUTO SEISMIC CALCULATION RESULTS T Used = sec C Used = W Used = V Used = W = Ft Used = 0.00 AUTO SEISMIC STORY FORCES STORY FX FY FZ MX MY MZ 4 (Forces reported at X = , Y = , Z = ) (Forces reported at X = , Y = , Z = ) (Forces reported at X = , Y = , Z = ) (Forces reported at X = , Y = , Z = ) G (Forces reported at X = , Y = , Z = )

21 b. Bending Moment c. Shear Forces 17

22 d. Storey Drift 18

23 CHAPTER 5 COMPARISON 1. Base Shear comparison a. BM and SF comparison BM AND SF COMPARISON STAAD Pro STRAP 2014 ETABS M A X B M - K N M M A X S F - KN b. Base shear and Displacement comparison 3000 BASE SHEAR AND DISPLACEMENT COMPARISON BASE Shear - SRSS (kn) Displcament (mm) STAAD Pro STRAP 2014 ETABS

24 c. Seismic weight comparison Seismic weight STAAD Pro STRAP 2014 ETABS 2013 Seismic weight d. Comparison table Results Staad Pro Strap 12.5 ETABS 2013 Base shear (SRSS) 634 kn 683 kn kn Seismic Weight kn kn kn Scale factor Maximum Bending Moment knm knm knm Maximum Shear Force kn kn kn Maximum Displacement 820mm 867 mm 790 mm 20

25 CHAPTER 6 CONCLUSION Actually the results of analysis should match with the classical analysis solutions, whatever the type of analysis we do using whatever S/W package. The finer thing that we should note in all these packages is that, there are parameters/properties such as boundary conditions, material properties etc., which are applied to the generated model by the software package by default at the initial stage. May be the ambiguity we observed in results arise due to these default prams. And these by default properties/ parameters changes from one S/W package to other. May be more inspection of these inputs may give better results! :) Sometimes closer or exact! :) 21

26 CHAPTER 7 REFERENCES [1] Giordano, M. Guadagnuolo and G. Faella PUSHOVER ANALYSIS OF PLAN IRREGULAR MASONRY BUILDINGS The 14th World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China. [2] Prof. K S Sable, Er. V A Ghodechor, Prof. S B Kandekar Comparative Study of Seismic Behavior of Multistory Flat Slab and Conventional Reinforced Concrete Framed Structures International Journal of Computer Technology and Electronics Engineering (IJCTEE) Volume 2, Issue 3, June [3] Belejo, R. Bento & C. Bhatt Comparison of different computer programs to predict the seismic performance of SPEAR building by means of Pushover Analysis the SPEAR building by means of Pushover Analysis Instituto Superior Técnico, Lisbon, Portugal [4] DISPLACEMENT BASED DESIGN OF VERTICALLY IRREGULAR FRAME-WALL STRUCTURES Rose school thesis work by SUHAIB SALAWDEH [5] Performance Based Seismic Design and Assessment of Irregular Steel Structures R. Peres, R. Bento IST, Technical University of Lisbon, Portugal J. M. Castro Faculty of Engineering, University of Porto, Portugal. [6] Seismic design of vertically irregular reinforced concrete structures Thesis work submitted by Satrajit Das [7] McCrum Lunch Seismic Analysis of Braced Plan Irregular Structures Using Hybrid Testing Daniel lecture at the Department of Civil, Structural & Environmental Engineering, Trinity College Dublin on 30th November 2011 [8] Shaikh Abdul Aijaj Abdul Rahman, Girish Deshmukh Seismic Response of Vertically Irregular RC Frame with Stiffness Irregularity at Fourth Floor ISSN ,ISO 9001:2008 Certified Journal, Volume 3, Issue 8, August