DECLARATION BY THE CANDIDATES
I, Ajitpal hereby declare that the project report entitled RESULT COMPARISON STAD PRO AND ETABS G+5 MULTISTORY BUILDING under the guidance of Dr. Harpal Singh is submitted in the fulfilment of the requirements for the PROJECT. This is a bonafide work carried out by me and the results calculated in this project report have not been copied from any source. The results in this project report have not been presented in any other degree or diploma.
INTRODUCTION The use of structure is human need from the early past but in early days the design of structures was a tedious job with lots of calculations. All the design work, analysis and calculation were done manually by referring to the design codes. With the passage of time the design of buildings evolved. With the evolution the design of the buildings became more complicated and difficult The complexity of concrete structures and fast-track projects makes a simplified structural model desirable during the preliminary design process. Likewise, in the preliminary design phase, working with the structure in all its complexity does not prove to be efficient. Instead, a highly simplified conceptual model of the basic structural system is sufficient. To be useful, the model should capture the essentials of the structural behavior and indicate the way the structure channels the applied loads in to the foundations. Thus, models and numerical results obtained from computerized preliminary design are most useful in estimating the behavior of structures. And for avoiding enormous calculations and errors and saving the time, we can rely on design software such as “STAAD-PRO and ETABS”. The software can solve typical problem like Static analysis, Seismic analysis and Natural frequency. This type of problem can be solved by STAAD-PRO and ETABS along with IS-CODE. Moreover, the greater advantage is, these software gives more accurate and precise result than the manual technique. I considered a 3D RCC frame of dimensions 30 m X 12 m. 30 m span is in X direction and 12 m span is in Z direction. The height of the each floor is 3.7 m. The Y axis consists of 6 floors. The structure is subjected to Self weight dead load, live load and seismic load. Seismic load calculations are done following IS 1893-2000. The materials are specified and cross-sections of the beam and column members were assigned. The supports at the base of the structure were taken as fixed. The codes of practice to be followed were also specified for design purpose with other important details. Then STAAD.Pro and ETABS were used to analyse the structure .
.1 Purpose of study The principle objective of this project is to analyse and compare the results of a multi-storeyed building using STAAD Pro and ETABS. The said softwares are among the leading design softwares and are used by many design firms for the purpose of designing. The user i9nteraface of STAAD.Pro and ETABS are very interactive which helps the user in easy drawing of frames and input the load values and dimensions. Then according to the specified criteria assigned it analyses the structure and designs the members with reinforcement details .
General A structure can be defined as a body which can resist the applied loads without appreciable deformations. Civil engineering structures are created to serve some specific functions like human habitation, transportation, bridge, storage etc. in a safe and economical way. A structure is an assemblage of individual elements like pinned elements (truss elements), beam element, column, shear wall slab cable or arch. Structural engineering is concerned with the planning, designing and the construction of structures. Structure analysis involves the determination of the forces and displacements of the structures or components of a structure. Design process involves the selection and detailing of the components that make up the structural system. The main object of reinforced concrete design is to achieve a structure that will result in a safe economical solution.
1.2 Introduction to softwares 1.2.1 STAAD Pro STAAD/Pro is an integrated engineering software package capable of structural analysis, design and drafting, all within the same program. It is the leading Structural Analysis and Design software from Research Engineers. STAAD/Pro addresses the entire process of structural engineering. From model development, to analysis, to design, to drafting, to detailing and even component design. STAAD/Pro is designed to work the way the Structural Design Office works. STAAD/Pro is developed and maintained using an extensive verification procedure. STAAD/Pro offers two analysis engines; the STAAD Analysis / Design Engine and the STARDYNIZ Advanced Analysis
engine. The STAAD analysis engine is described in this section. The contents of an input file are read processed and the results are written to an output file. In addition, this also creates plot files for further processing by the graphic modules in this section, only those portions of the software are covered which were actually used in analysing and designing the project structure. The ultimate for Computerized Structural Engineering, STAAD Pro is the next generation of the STAAD product line, the most powerful structural engineering software in the world. With over 150,000 installations, 15,000 clients, design codes for 30 countries and NRC/NUPIC certification, STAAD Pro is the choice of professional engineers around the world. STAAD Pro includes several new exciting features including integrated shear wall and two-way slab design, a full backup manager, physical members and moment connections for steel design and the ability to write macros inside of STAAD for further customization. Here are some short descriptions on the new features in STAAD Pro. Staad is powerful design software licensed by Bentley .Staad stands for structural analysis and design. Any object which is stable under a given loading can be considered as structure. So first find the outline of the structure, where as analysis is the estimation of what are the type of loads that acts on the beam and calculation of shear force and bending moment comes under analysis stage. Design phase is designing the type of materials and its dimensions to resist the load. This we do after the analysis. To calculate s.f.d and b.m.d of a complex loading beam it takes about an hour. So when it comes into the building with several members it will take a week. Staad pro is a very powerful tool which does this job in just an hour’s. Staad is a best alternative for high rise buildings. Now days most of the high rise buildings are designed by staad which makes a compulsion for a civil engineer to know about this software. This software can be used to carry rcc, steel, bridge, truss etc according to various country codes.
Limitations of Staad pro 1. Huge output data 2. Even analysis of a small beam creates large output. 3. Unable to show plinth beams .
1.2.2 Introduction to ETABS ETABS is sophisticated software for analysis and design program developed specifically for building systems. ETABS features an intuitive and powerful graphical interface coupled with unmatched modeling, analytical, and design procedures, all integrated using common database. Although quick and easy for simple structures, ETABS can also handle the largest and most complex building models, including a wide range of nonlinear behaviors, making it the tool of choice for structural engineers in the building industry. The innovative and revolutionary ETABS is the ultimate integrated software package for the structural analysis and design of buildings. ETABS offers unmatched 3D object based modelling 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. 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. 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 unequal suite of tools for structural engineers designing buildings, whether they are working on one-story industrial structures or the tallest commercial high-rises.
1.4 Statement of project Table 1:- Salient features of Buildings Sr No. 1 2 3 4
Salient features Utility of building Office building No of stories 5 Shape of the building Rectangular No. of rooms 5 halls
5 6
Type of construction Types of walls
R.C.C framed structure brick wall
Table 2:- Geometric details Sr No.
Geometric details
1
Floor to floor height
4.0m
2
Height of plinth
4.0 m
3
Size of column
0.5 m x 0.5 m
4
Size of beam B1
0.35m x 0.70 m
5
Size of beam B2
0.25m x 0.50m
6
Size of beam B3
0.30m x 0.50m
Table 3:- Material details Sr No. 1 2
Material details Concrete grade Steel grade
M25 Fe415
1.5 Design of multi storied residential building A structure can be defined as a body which can resist the applied loads without appreciable deformations. Civil engineering structures are created to serve some specific functions like human habitation, transportation, bridges, storage etc. in a safe and economical way. A structure is an assemblage of individual elements like pinned elements (truss elements), beam element, column, shear wall slab cable or arch. Structural engineering is concerned with the planning, designing and the construction of structures. Structure analysis involves the determination of the forces and displacements of the structures or components of a structure. Design process involves the selection and detailing of the components that make up the structural system. The main object of reinforced concrete design is to achieve a structure that will result in a safe economical solution. The column and beam design is done using limit state method.
CHAPTER-2 LITERATURE REVIEW SukumarBehera, National Institute of Technology, Rourkela (May 2012) studied the behavior of multistory building with and without floating column is studied under different earthquake excitation. The compatible time history and Elcentro earthquake data been considered with PGA scaled to 0.2g and duration of excitation kept same. A finite element model was developed to study the dynamic behavior of multistory frame. The static and free vibration results and the dynamic analysis of frame is studied by varying the column dimension and concluded that with increase in ground floor column the maximum displacement, inter storey drift values are reduced. The base shear and overturning moment vary with the change in column dimension Mr.S.Mahesh, Mr.Dr.B.Panduranga Rao (Department of Civil Engineering/ V R Siddhartha Engineering College, India) performed analysis and design of regular and irregular configuration of residential G+11 multistory building in various seismic zones and various types of soils using ETABS and STAAD Pro V8i. The behavior of G+11 multistory building of regular and irregular configuration under wind loads assumed to act simultaneously with earth quake loads. The analysis carried out by considering different seismic zones and for each zone the behavior is assessed by taking three different types of soils namely Hard, Medium and Soft. When compared the both the regular and irregular configuration, concluded that the base shear value is more in the regular configuration as the structure have more symmetrical dimensions and the story drift value is more in the regular configuration as the structure has more dimensions. Finally when compared the both software’s the STAAD PROV8i has more value. The area of the steel is 5 to 10%. Prashanth.P, Anshuman.S, Pandey.R.K, Arpan Herbert(2012) Compared design results of a Structure designed using STAAD and ETABS, regular and a plan irregular (as per IS 1893) multi storey building structure designed using STAAD Pro and ETABS softwares separately and concluded that ETABS gave lesser area of required steel as compared to STAAD Pro. Form the design results of column; since the required steel for the column forces in this particular problem is less than the minimum steel limit of column (i.e., 0.8%),
the amount of steel calculated by both the softwares is equal. So comparison of results for this case is not possible. K.Aslam, Sri Venkateshwar college of engineering and technology, Chennai (Apri, 2012) performed seismic analysis and design of multi storey hospital building with the earthquake resistant design consideration. Seismic analysis and design were done by using ETABS software and verified manually as per IS 1893-2002 the provision of shear wall in the staircase and lift region have the ultimate shear resistance, the total base shear produced by the earth quake for that maximum percentage of the shear resistance produced by the shear wall and the remaining shear resistance produced by the columns. Ashis Debashish Behera, National Institute of Technology, Rourkela (May2012) performed 3-D analysis and design of building frame using STAAD Pro and compared between two 30-storey building taking same beam and column size using different load combination and concluded that the top beams of a building in seismic load combination required more reinforcement than the building under wind load combination but the deflection and shear bending is more in wind load combination as compared to seismic. But in lower beams more reinforcement is required for wind load combination. For column the area of steel and percentage of steel always greater required for wind load combination than the seismic load combination. The deflection value is more in WL combination than the SL combination. AbhayGuleria, Deptt. Of Civil Engineering, J.N.G.E.C., Sundernagar, India studied structural analysis of a multi-storeyed building using ETABS for different plan configurations, the analysis of the multi-storeyed building reflected that the storey overturning moment varies inversely with storey height. Moreover, L-shape, I-shape type buildings give almost similar response against the overturning moment. Storey drift displacement increased with storey height up to 6th storey reaching to maximum value and then started decreasing. From dynamic analysis, mode shapes are generated and it can be concluded that asymmetrical plans undergo more deformation than symmetrical plans. Asymmetrical plans should be adopted considering into gaps and asymmetrical plans undergo more deformation and hence symmetrical plans must be adhered to.
CHAPTER-3
LOADINGS 3.1 Load Conditions and Structural System Response The concepts presented in this section provide an overview of building loads and their effect on the structural response of typical wood-framed homes. Building loads can be divided into types based on the orientation of the structural action or forces that they induce: vertical and horizontal (i.e., lateral) loads. Classification of loads are described in the following sections
3.2 Building Loads Categorized by Orientation :
Types of loads 1. 2. 3. 4. 5. 6. 7.
Vertical Loads Dead (gravity) Live (gravity) Snow(gravity) Wind(uplift on roof) Seismic and wind (overturning) Seismic( vertical ground motion)
3.2.1 Horizontal (Lateral) Loads Direction of loads is horizontal w.r.t to the building. 1. Wind 2. Seismic (horizontal ground motion) 3. Flood (static and dynamic hydraulic forces 4. Soil (active lateral pressure)
3.2.2 Vertical Loads
Gravity loads act in the same direction as gravity (i.e., downward or vertically) and include dead, live, and snow loads. They are generally static in nature and usually considered a uniformly distributed or concentrated load. Thus, determining a gravity load on a beam or column is a relatively simple exercise that uses the concept of tributary areas to assign loads to structural elements, including the dead load (i.e., weight of the construction) and any applied loads(i.e., live load).
3.2.3 Lateral Loads The primary loads that produce lateral forces on buildings are attributable to forces associated with wind, seismic ground motion, floods, and soil. Wind and seismic lateral loads apply to the entire building. Lateral forces from wind are generated by positive wind pressures on the windward face of the building and by negative pressures on the leeward face of the building, creating a combined push and-pull effect. Seismic lateral forces are generated by a structure’s response to cyclic ground movement. The magnitude of the seismic shear (i.e., lateral) load depends on the magnitude of the ground motion, the buildings mass, and the dynamic structural response characteristics (i.e., dampening, ductility, natural period of vibration, etc).for houses and other similar low rise structures, Lateral loads also produce an overturning moment that must be offset by the dead load and connections of the building. Therefore, overturning forces on connections designed to restrain components from rotating or the building from overturning must be considered.
3.3 Design loads for residential buildings Loads are a primary consideration in any building design because they define the nature and magnitude of hazards are external forces that a building must resist to provide a reasonable performance(i.e., safety and serviceability )throughout the structure’s useful life. The anticipated loads are influenced by a building’s intended use (occupancy and function), configuration (size and shape) and location(climate and site conditions).Ultimately, the type and magnitude of design loads affect critical decisions such as material collection, construction details and architectural configuration.
Thus, to optimize the value (i.e., performance versus economy) of the finished product, it is essential to apply design loads realistically. While the buildings considered in this guide are primarily single-family detached and and attached dwellings, the principles and concepts related to building loads also apply to other similar types of construction, such as low-rise apartment buildings. Since building codes tend to vary in their treatment of design loads the designer should, as a matter of due diligence, identify variances from both local accepted practice and the applicable code relative to design loads as presented in this guide, even though the variances may be considered technically sound. Complete design of a home typically requires the evaluation of several different types of materials.
3.3.1 Dead Loads Dead loads consist of the permanent construction material loads compressing the roof, floor, wall, and foundation systems, including claddings, finishes and fixed equipment. Dead load is the total load of all of the components of the components of the building that generally do not change over time, such as the steel columns, concrete floors, bricks, roofing material etc.
3.3.2 Live Loads Live loads are produced by the use and occupancy of a building. Loads include those from human occupants, furnishings, no fixed equipment, storage, and construction and maintenance activities .
3.3.3 Floor load Floor load is calculated based on the load on the slabs. Assignment of floor load is done by creating a load case for floor load.
3.3.4 Wind loads In the list of loads we can see wind load is present both in vertical and horizontal loads. This is because wind load causes uplift of the roof by creating a negative (suction) pressure on the top of the roof. Wind produces non static loads on a structure at highly variable magnitudes. The variation in pressures at different locations on a building is complex to the point that pressures may become too analytically intensive for precise consideration in design. Therefore, wind load specifications attempt to amplify the design problem by considering basic static pressure zones on a building representative of peak loads that are likely to be experienced. The peak pressures in one zone for a given wind direction may not, However, occur simultaneously in other zones. For some pressure zones, the peak pressure depends on an arrow range of wind direction. Therefore, the wind directionality effect must also be factored into determining risk consistent wind loads on buildings .
3.3.5 Load combinations All the load cases are tested by taking load factors and analysing the building in different load combination as per IS 456 and analysed the building for all the load combinations and results are taken and maximum load combination is selected for the design Load factors as per IS456-2000 There are many structural design software’s available out in the market to work with. All these structural design software have different functions and way of doing work and performing analysis as well. This structural design software are made to design and analysis of a building, bridges, culverts, etc. and these structural design software are like Staad-Pro, Etabs, SAP 2000, etc.
The load Combinations are LOAD 1 Seismic - EQX LOAD 2 Seismic - EQZ LOAD 3 Dead - DEAD LOAD
LOAD 4 Live - LIVE LOAD LOAD COMB 5 1.5(DL+LL)
DL x 1.5 and LL x 1.5
LOAD COMB 6 1.2(DL +LL)
DL x 1.2, LL x 1.2 LOAD COMB 7 1.2(GL+EQX)
DL x 1.2, LL x 1.2, EQX x 1.2 LOAD COMB 8 1.2(GL+EQZ)
DL x 1.2, LL x 1.2, EQZ x 1.2 LOAD COMB 9 1.2(GL-EQX)
DL x 1.2, LL x 1.2, EQX x(-1.2) LOAD COMB 10 1.2(GL-EQZ)
DL x 1.2 LL x 1.2 EQZ x (-1.2)
CHAPTER 4 METHODOLOGY
