ANALYSIS AND DESIGN OF MULTI-STOREYED BUILDING USING STAAD PRO PROJECT REPORT Submitted by
BYJU SUBHASH S DEEPU R RAKHI M P REMIZ S ROMI CHANDRA
Guided by Smt. Beena P. R. Assistant Professor DEPARTMENT OF CIVIL ENGINEERING COLLEGE OF ENGINEERING TRIVANDRUM
DEPARTMENT OF CIVIL ENGINEERING COLLEGE OF ENGINEERING TRIVANDRUM 2013
ANALYSIS AND DESIGN OF MULTI-STOREYED BUILDING USING STAAD PRO PROJECT REPORT Submitted in partial fulfillment of the requirement for the award of Degree of Bachelor of Technology in Civil Engineering of the University of Kerala
Submitted by BYJU SUBHASH S DEEPU R RAKHI M P REMIZ S ROMI CHANDRA
Guided by Smt. Beena P. R. Assistant Professor Department of Civil Engineering
DEPARTMENT OF CIVIL ENGINEERING COLLEGE OF ENGINEERING TRIVANDRUM 2013
CERTIFICATE
This is to certify that this project report is a bonafide report of the work done by BYJU SUBHASH, DEEPU R, ROMI CHANDRA, REMIZ S, RAKHI M P of Department of Civil Engineering, in partial fulfillment of the requirement for the award of Degree of Bachelor of Technology in Civil Engineering by the University of Kerala, during the academic year 2012-2013.
Project Guide Smt. Beena P. R. Assistant Professor Department of CE College of Engineering Trivandrum
Head of the Department Prof. Jyothis Thomas Department of CE College of Engineering Trivandrum
ACKNOWLEDGEMENT
We take this opportunity to express our sincere gratitude to all the staff of College of Engineering, Trivandrum for their constant encouragement given for the completion of this project. We express our gratitude to our guide Smt. Beena P. R, Assistant Professor, Department of Civil Engineering, Thiruvananthapuram, for the expert guidance and advice in completing our project.
We would like to express our heartfelt thanks to Prof. Jyothis Thomas, Head of Department, Department of Civil Engineering, College of Engineering, Trivandrum, for her wonderful support and co-operation during the course of this work. We would also like to thank Prof. M. B. Joisy, UG Professor, College of Engineering Trivandrum, and Dr. Jaya, Staff Advisor, Department of Civil Engineering, College of Engineering, Trivandrum for their help in completing this work.
We also take this opportunity to thank our parents, relatives and friends without whose support, encouragement and prayers, we would not have completed this report on time.
Last, but not the least, we would also like to thank almighty for providing us with such a host of good people to make this a success. BYJU SUBHASH DEEPU R RAKHI M P REMIZ S ROMI CHANDRA
ABSTRACT
STAAD or (STAAD.Pro) is a structural analysis and design computer program originally developed by Research Engineers International in Yorba Linda, CA. In late 2005, Research Engineer International was bought by Bentley Systems. The collected data is analysed and a 3-D model is generated using STAAD Pro. The various loads acting on the structure is calculated and the structure is analysed for the various load combinations. Design of the building is done. The obtained results are analysed. Manual calculation and design of slabs, beams, staircase and columns are done. Also the design of the pile foundation and pile cap is done.
CONTENTS 1. INTRODUCTION 1.1. AIM AND SCOPE OF WORK 1.2. SPECIFICATIONS 1.3. DESIGN PHILOSOPHIES 1.4. COMPONENTS OF THE STRUCTURE 1.4.1. DEEP FOUNDATION 1.4.1.1. SOIL TESTING 1.4.1.2. MIX DESIGN(FOR CONCRETING PILE) 1.4.1.3. CONCRETING OF PILE HOLE 1.4.2. PILE CAP 2. LITERATURE REVIEW 2.1. BYE LAWS IN PLANNING 2.1.1. MERCANTILE OR COMMERCIAL OCCUPANCY 2.1.2. MINIMUM DISTANCE FROM ROAD 2.1.3. SETBACK CRITERIA 2.1.4. SAFETY PROVISINS FOR HIGH RISE BUILDINGS 2.1.5. HEIGHT OF BUILDINGS 2.1.6. PARKING REQUIREMENTS 2.1.7. FLOOR AREA RATIO(FAR) CRITERION 2.1.8. COVERAGE CRITERION 2.1.9. PARKING PLANNING 2.1.10. FUNCTIONAL PLANNING 2.2. DESIGN CODES 2.3. BOOKS 3. ANALYSIS 3.1. STRUCTURAL ANALYSIS 3.2. ACTIONS 3.3. RESPONSE OF STRUCTURES 3.4. LOADS ACTING 3.4.1. DEAD LOADS 3.4.2. LIVE LOADS 3.4.3. WIND LOADS 3.4.4. EARTHQUAKE LOADS 4. INTRODUCTION TO STAAD 4.1. STEPS INVOLVED 4.1.1. GENERATION OF NODES 4.1.2. MODELLING OF THE STRUCTURE 4.1.3. ASSIGNING OF THE STRUCTURAL ELEMENTS
1 1 1 2 3 3 4 4 4 4 5 5 5 5 6 6 7 7 7 7 8 8 15 17 18 18 18 18 18 19 20 22 22 26 27 28 28 28
4.1.4. RESTRAINTS 4.1.5. APPLICATION OF LOADS 4.1.6. RUN ANALYSIS
29 29 30
5. METHODOLOGY 6. LOAD CALCULATION 6.1. CALCULATION OF WIND LOADS 6.2. CALCULTION OF SEISMIC LOADS 6.2.1. GRAVITY LOAD CALCULATIONS 6.3. ASSUMPTIONS 6.4. LOAD COMBINATIONS
31 32 32 33 33 38 39
7. DESIGN OF STRUCTURE 7.1. DESIGN OBJECTIVES 7.2. DESIGN CRITERIA
41 41 41
7.3. DESIGN PROCESS 7.4. DETAILING 8. MANUAL DESIGN 8.1. DESIGN OF BEAMS 8.1.1. BEAM 8 8.2. DESIGN OF COLUMNS 8.2.1. COLUMN 995
42 42 43 43 43 45 45
8.3. DESIGN OF SLABS
50
8.3.1. SLAB S1 8.4. DESIGN OF STAIRS 8.4.1. MAIN STAIRCASE 9. PLANNING AND DESIGN OF FOUNDATION 9.1. INTRODUCTION 9.2. PILE DESIGN THEORY 9.3. PILE CAPACITY DETERMINATION 9.4. PILE GROUP DETERMINATION 9.5. ANALYSIS OF PILES 9.6. DESIGN OF PILES 9.7. DESIGN OF TIES 9.8. DESIGN OF PILE CAP 10.CONCLUSION 11.REFERENCE
50 51 51 52 52 52 53 54 55 55 58 59 63 64
LIST OF TABLES
1. 2. 3. 4. 5. 6.
Live loads Wind intensity calculation Distribution of hori. earthquake force along height of building Pile groups & column classification based on loads Max. Axial and lateral loads in a pile group Abstract of design of piles 7. Abstract of pile cap design
21 33 38 55 55 59 62
LIST OF FIGURES 1. Elevation of the Hostel Building 2. Ground Floor Plan 3. First Floor Plan 4. 3D View 5. Dead Loads 6. Live Loads 7. Earthquake Load in +X direction 8. Earthquake Load in +Z direction 9. Earthquake Load in -X direction 10.Earthquake Load in -Z direction 11.STAAD.Pro Window 12.Modelling of the structure 13.Restraints 14.Run Analysis 15.Load Combinations 16.Beam NO:8 17.Column No:995
11 12 13 14 20 21 23 24 24 25 27 28 29 30 40 45 49
1. INTRODUCTION 1.1 AIM AND SCOPE OF WORK Human life is affected due to nature’s forces like floods, hurricanes, tornadoes, earthquakes etc. The structural design for a building must ensure that the building is able to stand safely, to function without excessive deflections or movements which may cause fatigue of structural elements, cracking or failure of fixtures, fittings or partitions, or discomfort for occupants. It must account for movements and forces due to temperature, creep, cracking and imposed loads. It must also ensure that the design is practically buildable within acceptable manufacturing tolerances of the materials. It must allow the architecture to work, and the building services to fit within the building such that it is functionable (air conditioning, ventilation, lighting etc.). The aim of this project work is to analyze a 5-storeyed hostel building for different load combinations using STAAD Pro software. Based on the analysis, design of the structure is done mainly in accordance with IS specifications.
1.2 DESIGN PHILOSOPHIES The limit state method is adopted for the analysis and design of the structure. IS codes, SP-16 and SP-32 charts are also used as an aid for detailing and design purpose. The major requirements of a properly designed building are:
(a) GOOD STRUCTURAL CONFIGURATION: Its size, shape and structural system carrying loads are such that they ensure a direct and smooth flow of inertia forces to the ground. (b) LATERAL STRENGTH: The maximum lateral (horizontal) force that it can resist is such that the damage induced in it does not result in collapse. (c) ADEQUATE STIFFNESS: Its lateral load resisting system is such that the earthquakeinduced deformations in it do not damage its contents under low-to moderate shaking. (d) GOOD DUCTILITY: Its capacity to undergo large deformations under severe earthquake shaking even after yielding is improved by favourable design and detailing strategies.
1
1.3 COMPONENTS OF THE STRUCTURE The components of the structure are mainly classified into (a) Superstructure (b) Substructure Superstructure is the part of the building that lies above the ground line. These are subjected to lateral loads like the wind load, earthquake load, and other dead and live loads. Substructure is the foundation of the building. The type of foundation adopted for the hostel building under consideration is pile foundation.
1.3.1 PILE FOUNDATION A deep foundation is a type of foundation distinguished by the depth on which they are embedded into the ground. Piles are generally driven into the ground in situ. The types of piling are DMC Piling and rotary piling. In DMC Pile Foundation the bentonite suspension is pumped into the bottom of the hole through the drill rods and it overflows at the top of the casing. The mud pump should have the capacity to maintain a velocity of 0.41 to 0.76 m/s, to float the cuttings. The depth of piling was decided by testing the underground soil samples (to obtain level bed). It is not possible in hard rocks. Tremie pipe is inserted into pile holes for pile concreting.
2
2. LITERATURE REVIEW 2.1 BYE LAWS IN PLANNING 2.1.1 MERCANTILE OR HOSTEL OCCUPANCY Apartment means a part of a building intended for any type of independent use including one or more rooms or enclosed spaces located on one or more floors or parts thereof in a building, intended to be used for residential purposes and with a direct exit to a public street, road or highway or to a common area, leading to such street, road or highway. This word is synonymous with residential flat. No land development or redevelopment shall be made or no building shall be constructed on any plot on any part of which there is deposited refuse, excreta or other offensive matter which in the opinion of the Secretary is considered objectionable, until such refuse, excreta or other offensive matter has been removed there from and the plot has been prepared or left in a manner suitable for land development or building purpose for the satisfaction of the Secretary. The rear yard shall be not less than 1.5m depth. Parking building/parking plazas/parking towers shall have minimum 5m open space all around the building. Not more than 15% of the total floor area of the parking building shall be permitted for shop or restaurant or hotel or office purpose.
2.1.2 MINIMUM DISTANCE FROM THE ROAD For buildings above 10m in height, in addition to the minimum front, rear and side open spaces required for height upto 10m, there shall be provided proportionate increase in such minimum open space at the rate of 0.5m per every 3m height exceeding 10m. No construction or hanging of any sort shall be permitted to project outside the boundaries of the site. Every open space provided, either interior or exterior shall be kept free from any erection thereon and shall be open to the sky and only cornice, roof or whether shade not more than 0.6m width
3
shall overhang or project over the said open space so as to reduce the width to less than the minimum required.
2.1.3 SETBACK CRITERIA The minimum distance between the plot boundary abutting any street other than National Highways, State Highways, District Roads and other roads notified by the municipality and the building, other than a compound wall or fence or outdoor display structure, shall be minimum 1.50 metres. Front yard shall have minimum 1.00 metre width.Minimum setbacks required for a residential building of 10m height above ground level as per KMBR is: Front yard
= 3m
Rear yard
= 3m
Side clearance
= 1.5m on either sides
Horizontal distance from the centre line of the street = 7.5m
2.1.4 SAFETY PROVISIONS FOR HIGH RISE BUILDINGS High rise building means a building having more than four floors and or 15m of height from ground level. Every high rise building shall have at least two staircases. The height of the handrail in the staircase shall not be less than 90cm and if balusters are provided no gap in the balusters shall be more than 10cm wide. Every slab or balcony overlooking any exterior or interior open space, 2m or more below shall be provided with parapet walls or guard rails of height not less than 1.20m and such guard rails shall be firmly fixed to the walls and slabs and may also be of blank walls, metal grills or a combination of both. Every high rise building shall be provided with a fire escape stairway. External fire escape staircase shall have straight flight not less than 75 cm wide, with 20 cm treads and risers not more than 19 cm. the number of risers shall be limited to 16 per flight. The height of handrails
4
shall be not less than 100 cm and not more than 120 cm. Every opening provided to ducts from the interior of a building is closed with strong materials.
2.1.5 HEIGHT OF BUILDINGS The maximum height of the building or part thereof shall not exceed twice the width of the street abutting the plot plus twice the width of the yard from the building to the abutting street and this height may further be increased proportionately at the rate of 3m for every 50cm, by which the building or the corresponding portion or floor of the building is set back from the building line.
2.1.6 PARKING REQUIREMENTS Parking requirements shall be reduced in proportion to the percentage of land surrendered to the extent that after such deduction a minimum of 75% of the parking required as per these rules
shall be provided. 2.1.7 FLOOR AREA RATIO (FAR) CRITERION It is the ratio of the total floor area on all floors to the plot area. KBR limits the maximum value to 2.5.
Floor Area Ratio
=
2.1.8 COVERAGE CRITERION It is the ratio of plinth area to the area of the plot. Kits restricted to a maximum value of 65, for hostel complexes, as per KMBR.
Coverage = .
5
2.1.9 FUNCTIONAL PLANNING Since the building is to be utilized for large dormitory rooms, large uninterrupted floor spaces are provided. Column spacing is provided to generate sufficient dormitory area ranges between 6 and 10m. Considering these planning aspects model of the proposed building is generated in STAAD Pro and is designed and analysed.
2.2 DESIGN CODES The various IS codes used for the project includes: IS 456:2000 Indian Standard plain and reinforced concrete code of practice. IS 456:2000, which is the key code for the design of all reinforced concrete (RC) structures has added new dimensions to the present scenario and its relevance in designing earthquake-resistant structures is to be seen in true perspective. IS 456:2000 recommends the use of IS 13920: 1993 and IS 4326: 1993 for detailing of earthquake resistant constructions IS 1893 (Part I):2002 Indian Standard Criteria for Earthquake Resistant Design of Structures (5th Revision) This standard contains provisions that are general in nature and applicable to all structures. Also, it contains provisions that are specific to buildings only. It covers general principles and design criteria, combinations, design spectrum, main attributes of buildings, dynamic analysis, apart from seismic zoning map and seismic coefficients of important towns, map showing epicenters, map showing tectonic features and lithological map of India. It is not intended in this standard to lay down regulation so that no structure shall suffer any damage during earthquake of all magnitudes. It has been endeavored to ensure that as far as, possible structures are able to respond, without structural damage to shocks of moderate intensities and without total collapse to shocks of heavy intensities.
6
IS 875 (Part 2):1987 R 1197 Code of practice for design loads (other than earthquake) for buildings and structures - Imposed loads IS 875 (Part 2) deals with various live loads to be considered for design of buildings. IS 875 (Part3):1987 R 1197Code of practice for design loads (other than earthquake) for buildings and structures - Wind Loads IS 875 (Part 3) deals with wind loads to be considered when designing buildings, structures and components.
USE OF SPECIAL PUBLICATIONS IS 456 has structural practice handbook SP:16-1980, Design Aids for Reinforced Concrete to IS:456-1978 has tables and charts that helps in rapidly design simple sections. Even though the design aid is based on the 1978 code, it continues to be used without revision as there have been no major changes to Structural Design (Limit State Method), on which the design aid is based.
2.3 BOOKS Design of RCC Structures by B. C. Punmia The concepts and principles of design of various structural members including beams, columns, stairs, slabs, footings etc. are explained in detail. Limit State Design of Reinforced Concrete by P. C. Varghese Reinforced Concrete Design by S. N. Sinha Reinforced Concrete Limit State Design by Ashok K Jain Basic & Applied Soil Mechanics by Gopal Ranjan & A. S. R. Rao Geotechnical Engineering by K. R. Arora
7
3. BUILDING DETAILS The building which we considered for the project is a 5-storeyed hostel building located at Trivandrum The ground floor consists of 2 Dormitories, Mess Hall, Kitchen, Pantry,Work Area, Store and Toilets. The plinth area distribution is as Ground floor-526 sq.m, Porch-51 sq.m A 2.0 m wide passage runs along thw whole length of the hostel building. A 9.9x5 Porch is provided. The First, Second, Third and the Fourth floor consists of 4 Dormitories and 2 Toilet blocks. The Elevation(Fig. 1), Ground Floor Plan(Fig. 2), First Floor Plan(Fig. 3) and a 3D view(Fig. 4) of the hostel building is provided.
8
Fig. 1 Elevation of the Hostel building
9
Fig. 2 Ground Floor Plan
10
Fig. 3 First Floor Plan
11
Fig.4 3-D view
12
4. ANALYSIS A structure consists of an assembly of individual structural elements such as truss elements, beams, columns, slabs, cable or arch proportioned to resist the loads and forces.
4.1 STRUCTURAL ANALYSIS It’s the calculation of the response of the structures to actions.
4.2 ACTIONS An action is a physical phenomenon that produces stress and deformation in the structures. Actions include:
Loads(self weight)
Variation in temperature
Settlement of support
4.3 RESPONSE OF STRUCTURES It’s the physical change produced in structure due to action on structures. It includes,
External Force quantities – Reactions
Internal Force quantities – Bending Moment, Shear, Axial force and stress
Displacement quantities – Deflection and Strain
The response of structure is calculated mathematically.
4.4 LOADS ACTING Loads can usually be considered to be primary or secondary. Secondary loads are those loads due to temperature changes, construction eccentricities, shrinkage of structural materials, settlement of foundations, or other such loads. Despite the fact that each and every load and loading
13
combination should be considered in order to reduce the chance of structural failure, the determination of the loading remains a statistical exercise. Each and every load cannot be foreseen; thus, it is critical to determine the worst case that is reasonable to assume to act upon the structure. The sources of primary loading include the materials from which the structure was built, the occupants, their furniture, and various weather conditions, as well as unique loading conditions experienced during construction, extreme weather and natural catastrophes. Primary loads are divided into DEAD LOADS and LIVE LOADS. When considering the possible combinations of these two categories of loading, the odds of certain loads occurring simultaneously are assumed to be null. CALCULATION: The loads taken for analysis are dead load, live load, wind load and seismic load. Since the structure will be erected in zone-3, seismic design should also be done. The loading standards ensure structural safety and eliminate wastage that may be caused due to unnecessary heavy loading without proper assessment.
4.4.1 DEAD LOADS Dead Loads are those loads which are considered to act permanently; they are "dead," stationary, and unable to be removed. The self-weight of the structural members normally provides the largest portion of the dead load of a building. Permanent non-structural elements such as roofing, concrete, flooring, pipes, ducts, interior partition walls, Environmental Control Systems machinery, elevator machinery and all other construction systems within a building must also be included in the calculation of the total dead load. It is calculated as per IS 875 (Part-1):1987. Unit weight of RCC and brickwork is adopted as 25kN/m3 and 20 kN/m3 respectively. Fig. 5 shows how Dead Load is input in STAAD Pro.
14
Fig. 5 Dead Load
4.4.2 LIVE LOADS Live loads, referred to as probabilistic loads or imposed loads, are temporary, of short duration, or moving. These dynamic loads may involve considerations such as impact, momentum, vibration, slosh dynamics of fluids, fatigue, etc. The magnitudes of live loads are difficult to determine with the same degree of accuracy that is possible with dead loads. They are determined from code provisions. The load assumed to be produced due to intended use or occupancy of a building including the weight of movable partitions, distributed and concentrated loads, impact and vibration loads, excluding wind load, seismic load and stress due to variation in temperature etc, are obtained from IS 875 (Part-2):1987. Fig. 6 shows the STAAD provision for including Live Load and the magnitude of Live Loads for different parts of the building is given in Table 1.
15
Fig 6. Live Load
Table 1: Live Loads Sl No.
Occupancy Classification
UDL (kN/m2)
1
Store
6
2
Kitchen
4
3
Corridor
4
16
4.4.3 WIND LOADS Wind is the relative motion of air to the surface of the earth. Wind speed in atmospheric boundary layer increases with height form zero at ground level to maximum at gradient height, the slight change in wind direction, within this height is neglected. Typically, buildings are designed to resist a strong wind with a very long return period, such as 50 years or more. The design wind speed is determined from historical records using Extreme value theory to predict future extreme wind speeds.
4.4.4 EARTHQUAKE LOADS Seismic loading is one of the basic concepts of earthquake engineering which means application of an earthquake-generated agitation to a structure. It happens at contact surfaces of a structure either with the ground, or with adjacent structures, or with gravity waves from tsunami. Seismic loading depends, primarily, on:
Anticipated earthquake’s parameters at the site - known as seismic hazard
Geotechnical parameters of the site
Structure’s parameters
Sometimes, seismic load exceeds ability of a structure to resist it without being broken, partially or completely. Due to their mutual interaction, seismic loading and seismic performance of a structure are intimately related. Fig. 7,8,9,10 shows how EQ load is included in the analysis using STAAD Pro.
17
Fig. 7 Earthquake Load in +X direction
Fig. 8 Earthquake Load in +Z direction
18
Fig. 9 Earthquake Load in –X direction
Fig 10 Earthquake Load in –Z direction
19
5. INTRODUCTION TO STAAD The stress analysis on the fields of civil, mechanical and aerospace engineering is invariably complex and for many of the problems, it is extremely difficult to obtain analytical solutions. For most of the practical problems, the engineer resorts to numerical methods that provide approximate but acceptable solutions. With the advent of computers, software’s were developed for the analysis of structures of complex shapes and complicated boundary conditions. A number of packages are hostelly available for wide range of applications. STAAD is one among them. The major features are: (i)
Element library
(ii)
Analysis capabilities and range of library - linear static analysis - heat transfer analysis - non- linear static analysis - stability analysis - dynamic analysis - coupled field analysis
(iii)
Types of loading
(iv)
Boundary conditions
(v)
Material properties and models
(vi)
Pre and Post processing
STAAD Pro is widely used software for structural analysis and design from research engineers international. It is capable of analyzing and designing structures consisting of frame, plate bar-shell and solid elements. It consists of GUI and analysis and design engine. The STAAD analysis and design engine is a general purpose calculation engine for structural analysis and integrated steel concrete, timber and aluminium design. Fig. 11 shows a typical STAAD Pro Window.
20
Fig. 11 STAAD.Pro Window
5.1 STEPS INVOLVED STAAD Pro 2004 is an effective software tool for the analysis and design of structural members. Hence this software could be used to design a structure against earthquake. The software follows the matrix stiffness principle in analyzing the structure. The steps for analyzing a structure using STAAD Pro 2004 are given below.
Generation of Nodes
Modelling of the Structure
Assigning of the structural members
Restraints
Application of loads
Run analysis
21
5.1.1 GENERATION OF NODES The nodes are generated based on the dimensions of the building. The building is divided into equal number of known grids. Then the grid spacing is given on the STAAD PRO 2004 window. The software automatically generates grids with specified spacing.
5.1.2 MODELLING OF THE STRUCTURE After the nodes are created they are joined with line elements(Fig. 12). Based on the dimension of the building the nodes are joined. Unwanted nodes could be deleted.
Fig. 12 Modeling of the structure
5.1.3 ASSIGNING OF THE STRUCTURAL ELEMENTS The software has the facility to assign the structural elements. The line elements have to be assigned as beams and columns and appropriate dimensions are given.
22
5.1.4 RESTRAINTS After the structure has been modeled the restraints has to be given. Usually fixed supports are given(Fig. 13)
Fig. 13 Restraints
5.1.5 APPLICATION OF LOADS There are various loads acting on a structure. Our project study constitutes the analysis of the following loads
Self Weight
Gravity Load
Wind Load
Seismic Load
The loads are applied on the structure as gravity loads (Dead and live loads), Joint loads (Seismic loads). After the application of different loads, combination of loads has to be specified as mentioned in IS 456:2000.
23
5.1.6 RUN ANALYSIS When the last step, run analysis is executed it shows “Analysis complete”, which indicates the termination of analysis process(Fig. 14). Based on the analysis results, the building is designed in accordance with the provisions mentioned in the Indian Standard Codes.
Fig. 14 Run Analysis
24
6. METHODOLOGY The various steps involved in the project are:
Data Collection
Analysis of the data
Model generation
Load calculation
Building analysis
Design of building
Result analysis
Manual calculation and design of slabs, beams, staircase and columns
Design of pile foundation and pile cap
25
7. LOAD CALCULATION Dead loads and live loads are given as per code provisionsIS 875 (Part I):1987 is used for dead loads and IS 875 (Part-II):1987, for live loads. Wind loads and Seismic loads have to be calculated according to IS 875 (Part-III):1987 and IS 875 (Part-IV):1987 respectively. The calculation procedure is shown as follows.
7.1 CALCULATION OF WIND LOADS The basic wind speed (Vb) for different wind zones of India are obtained from IS 875 (PartIII):1987 form which, the basic wind speed for each storey height ‘z’ is calculated as per the equation (1). Vz = Vb× k1×k2× k3
Pz = 0.6Vz2 (N/m2) Where, Vz = Design speed at any height ‘z’, in m/s. Vb = Regional basic wind speed(as per Appendix A, IS 875 (Part III) 1987) k1 = Probability factor as per Clause 5.3.1, IS 875 (Part-III):1987 k2 = Terrain, height and structure size height as per Clause 5.3.2, IS 875 (Part-III):1987 k3 = Topography factor, as per Clause 5.3.3, IS 875 (Part-III):1987
Pz = Intensity of wind pressure.
26
Table 2: WIND INTENSITY CALCULATION FLOOR
HEIGHT (m)
Vb
k1
k2
k3
Vz=Vb× k1× k2x k3 (m/s)
Ground floor
3
39
1.06
1.07
1
44.23
Pz= 0.6Vz (N/m2) 1173.77
First floor
6
39
1.06
1.07
1
44.23
1173.77
Second Floor
9
39
1.06
1.07
1
44.23
1173.77
Third Floor
12
39
1.06
1.07
1
44.23
1173.77
Fourth Floor
15
39
1.06
1.07
1
44.23
1173.77
2
7.2 CALCULATION OF SEISMIC LOAD The country is classified based on the magnitude of earthquake forces, into 4 seismic zones, II to V. The structure considered for our project falls under zone III area. The effect of seismic forces ie, the intensity and duration of the vibrations, depend on the magnitude of earthquake, depth of focus from the ground surface, distance of the structure under consideration from the epicenter, soil strata in which it is constructed, characteristics of the path through which the seismic waves travel. The response of a structure to ground vibrations is a function of the nature of foundation soil; materials, form, size and mode of construction of structures; and the duration and characteristics of ground motion. The design approach adopted in this standard ensures that structures possess at least a minimum strength to withstand minor earthquakes (
27
The different steps involved in the calculation of seismic load manually are explained below.
7.2.1 GRAVITY LOAD CALCULATIONS I. UNIT LOAD CALCULATIONS Assumed sizes of beam and column sections are: Column: 230 × 500 Area, A=0.115 m2 I=0.00057 m4 Beam: 230 × 500 Area, A=0.115 m2 I=0.00057 m4 Member Self Weights: Column (230 × 500) 0.5 × 0.23 × 25 = 2.875 KN/m Beam (230 × 500 ) 0.23 ×0.5 × 25 = 2.875 KN/m Slab (150 mm thick ) 0.15 × 25= 3.75 KN/m2 Brick wall (200 mm thick) 0.2 × 20 = 4 KN/m2 Floor wall (Height 2.5 m) (200 mm thick) : 2.5× 4 = 10 KN/m
28
Terrace Parapet (Height 0.6 m) 0.6 × 0.1 ×20 = 1.2 KN/m
II. SLAB LOAD CALCULATION Area
= 610.38 m2
Terrace floor Slab weight = 610.38× 0.15 × 25 = 2288.93kN Floor Finish= 610.38× 1 = 610.38kN Water Proofing = 610.38× 2 =1220.76kN Total = 4120.07 KN Typical floor Total = Slab weight +Floor finish =2899.31kN Stair room floor: Total weight = 13.02×.15 ×25 = 48.825kN III.BEAM LOAD CALCULATION Total Length= 394.66 m Beam load in each floor =394.66×0.5 × 0.23 × 25 =1134.6kN
29
IV. COLUMN LOAD CALCULATION 67× 3 × 0.23 × 0.500 × 25 = 577.88kN
V.WALL LOAD CALCULATION 20 mm thick wall in typical floor: 137× 10 =1370 kN 20 mm thick wall in ground floor: 137 × 10 =1370 kN 20 mm thick wall in the stair room: 6.57× 10=65.7 kN Parapet in terrace floor: 66 × 10 =660 kN VI. STAIR LOAD CALCULATION Stair 1 =1.585 × 25 =39.625 kN Stair 2 = 1.4 × 25 = 35kN VII. Seismic Weight Calculations: The seismic weights are calculated in a manner similar to gravity loads. The weight of columns and walls in any storey shall be equally distributed to floors above and below the storey. Following reduced live loads are used for analysis: Zero on terrace , and 50% on other floors (IS: 1893 (Part 1):2002, Clause 7.4) Terrace: Slab
=1585.17
Parapet
= 660
Walls
= 685
Beams
= 200
Columns
= 134
30
Stair
= 33.7
Total
= 3298 KN
Storey 5,4,3,2: Slab
=1115.49
Walls
=1370
Beams
=200
Columns
= 267.375
Stair
=16.85
Total
=2970
The seismic weight of the building is the lumped weight, which acts at the respective floor level at the centre of mass of the floor. VIII DESIGN SEISMIC LOAD The fundamental time period: Ta
=.075 × h × 0.75
[IS 1893 (Part I):2002, Clause 7.6.1]
=.075 × 15.5 × 0.75 = 0.87 sec. Zone factor, Z = 0.16 for Zone III
[IS 1893 (Part I):2002, Table 2]
Importance factor, I
[IS 1893 (Part I):2002, Table 6]
= 1.0
Rocky, or hard soil site and 5% damping =
31
. =1.15
[IS 1893 (Part I):2002, Figure 2]
The structure is assumed as Ordinary Moment Resisting Frame (OMRF) Response reduction factor, R = 3 Ah
[IS 1893 (Part I):2002 , Table 7]
=
= = 0.031 Base Shear, Vb = Ah × W = 0.031 × 13912 = 427 KN The total horizontal load of 427 KN is now distributed along the height of the building as per clause 7.7.1 of IS 1893 (Part 1): 2002. This distribution is shown in Table below.
Table 3: Distribution of horizontal Earthquake force along height of building
STOREY
Wi (KN)
Qi = (
hi (m)
)×Vb (KN)
5
3298
15. 5
792.344
223.986
4
2970
11.55
396.2
112.0009
3
2970
8.55
217.11
61.37436
2
2970
5.55
91.48
25.86028
1
1704
2.8
13.36
3.77671
∑ Wi = 13912
∑
32
= 1510.5
∑ Qi = 426.9983
7.3 LOAD COMBINATIONS The loads are evaluated separately and various combinations are determined from IS 875 (Part-5):1987. The combination is selected based upon their probability of acting together and their disposition in relation to other loads and severity of stresses or deformation caused by the combination of various loads in necessary to ensure required safety and economy in the design of the structure. For achieving the same, various load combinations are adopted. It should be recognized in load combinations that the simultaneous occurrence of maximum values of wind, earthquake and imposed loads is not likely. Combinations considered for the analysis includes 1.5 Dead Load+ 1.5 Live Load 1.2 Lead +1.2 Live Load +1.2 EQX Load +1.2 EQZ Load 1.2 Dead Load +1.2 Live Load -1.2 EQX Load -1.2 EQZ Load 1.5 Dead Load +1.5 EQX Load +1.5 EQZ Load 1.5 Dead Load -1.5 EQX Load -1.5 EQZ Load 0.9 Dead Load +1.5 EQX Load + 1.5 EQZ Load 0.9 Dead Load -1.5 EQX Load - 1.5 EQZ Load 1.0 Dead Load +1.0 Wind Load 1.0 Dead Load +1.0 Live Load + 1.0 Wind Load
Fig. 15 shows method of selecting load combination in STAAD Pro.
33
Fig 15 Load Combinations
34
8. DESIGN OF STRUCTURE 8.1 DESIGN OBJECTIVES (a) To configure a workable and economic structural system. This involves the selection of the appropriate structural types and laying out the location and arrangements of the structural elements such as columns and beams (b) To select structural dimension, depth and width of individual member and concrete cover (c) To determine the required reinforcement, both longitudinal and transverse (d) Detailing of reinforcement such as development length, hooks and bends (e) To satisfy serviceability requirements such as deflection and crack width
8.2 DESIGN CRITERIA In achieving the design objectives, there are four major design criteria of “SAFE” that must be satisfied. (a) Safety, Strength and stability: Structural systems and members must be designed with sufficient margins of safety against failure. (b) Aesthetics: It includes much consideration as shape, geometrical proportion, symmetry, texture and articulation. (c) Functional requirements: A structure must always be designed to serve its intended function as specified by the project requirements. Constructability is a major part of the functional requirement. A structural design must be practical and economical to build. (d) Economy: Structures must be designed and built in the target budget of the project. Design that replicates member sizes and simplify reinforcement placement to result in easier and faster construction will naturally result in being more economical than a design that achieves minimum material quantities.
35
8.3 DESIGN PROCESS (a) Configure the structural system (b) Determine the design data. This includes the design loads, design criteria and specifications. Also specify the material properties. (c) Make a first estimate of the material properties and sizes. For example, based on thumb rules, sizes are fixed for deflection control in addition to other functional or aesthetic requirements. (d) Calculate member cross sectional properties. Now perform structural analysis to obtain internal force demands such as moments, axial force, shear force and torsion. From these parameters, magnitudes of deflections of structural members are obtained. (e) Calculate the required longitudinal reinforcements based on moment and axial force demands. Calculate the required transverse reinforcements from the shear and torsional moment demands. (f) If members do not satisfy “SAFE” criteria modify the design and make changes to steps 1 and 3. (g) Complete the detailed evaluation of member design to include additional load cases, combinations, strength and serviceability requirements required by code and specifications. (h) Detailing of reinforcements. Develop design drawings and construction specifications. 8.4 DETAILING The hostel building being designed is located in seismic zone III. The building is analysed as OMRF(Ordinary Moment Resisting Frame) and RRF(Response Reduction Factor) is taken as 3. So the detailing is done accordingly.
36
9. MANUAL DESIGN 9.1 DESIGN OF BEAMS 9.1.1 BEAM NO: - 8 BEAM SECTION 230 mm × 500mm END SUPPORT Moment, M = 64.53 kN Factored Moment, Mu =1.5 × 64.53 = 96.79 kN Mu, lim = 0.36 ×
× (1-0.42
) × bd2 fck
= 0.36 ×0.48 × (1-0.42 × 0.48) × 230 × 462.52× 25 = 169.689 kNm Mu < Mu,lim Design as singly reinforced beam Mu = 0.87 ×fy×Ast× d × (1 -
)
64.53 × 106 =0.87 × 415 ×Ast× 462.5 × (1 Ast = 413.59 mm2 Assuming 12 mm diameter bars, Number of bars =
=4 Therefore, provide 4 nos of 12 mm diameter bars Ast provided = 452.12 mm2 Percentage reinforcement = = 0.42 %
37
)
Minimum Ast = = 217.87 mm2 < Ast provided Maximum Ast = 0.04bD = 4600 mm2 > Ast provided MIDSPAN Moment, M =49 kNm Factored moment, Mu = 1.5 × 49 = 73.5 kNm Mu, lim= 169.689 kNm Design as singly reinforced beam Mu = 0.87 ×fy×Ast× d x (1 -
)
73.5 × 106 =0.87 × 415 ×Ast× 462.5 × (1 Ast = 475.42 mm2 Assuming 12 mm diameter bars, Number of bars =
=5 Therefore, provide 5 nos of 12 mm diameter bars Ast provided = 565.48 mm2 Percentage reinforcement = = 0.53 % Minimum Ast = = 217.87 mm2 < Ast provided
38
)
Maximum Ast = 0.04bD = 4600 mm2 > Ast provided
Fig. 16 Beam No:8
9.2 DESIGN OF COLUMNS 9.2.1 COLUMN 995 COLUMN SECTION 230mm × 500mm Pu = 2280.63 kN Mux = 22.572 kNm Muz = 60.796 kNm Unsupported length = 3 - 0.5 = 2.5 m Effective length, leff = 0.7 × 2.5
= 1.75 m 39
= = 7.6 Therefore, it is a short column. As per clause 25.4 of IS 456:2000,
ex =
= = 9.89 mm
ez =
= = 9.66 mm
ex min =
+
=
+
= 21.67 mm ez min =
+
=
+
= 26.66 mm Biaxial Bending Mu = 1.15 √ = 1.15 √ = 74.58 kNm
= = 0.09
40
= = 0.49 = = 0.03 From chart 32 of SP 16. = 0.04 p = 1.6% Asc =
× 230 × 500
=1840 mm2 Asc min =
× 230 × 500
= 920 mm2 Asc max =
× 230 × 500
= 6900 mm2 Providing 25 mm diameter bars, No: of bars =
=4 Therefore, provide 4 no’s 25 mm diameter bars. Asc provided =1963.49 mm2 > 1840 mm2
= = 0.49
41
pprovided =
× 100
= 1.7%
= = 0.0425 = = 0.09 = 0.06 Mux1 = 0.06 × 40 × 230 × 5002 = 138 kNm Muz1 = 0.06 × 40 × 500 × 2302 = 63.48 kNm Check Puz =0.45 fck Ac + 0.75 fyAsc =0.45 × 40 × [230 × 500 -2412.74] + 0.75 × 415 × 2412.74 = 2777.54 kN Pu = 2280.63 kN
= = 0.8 αn = 2 As per clause 39.6 of IS 456:2000
+
=
+
= 0.94
42
< 1.0 Hence the column is safe in biaxial bending
Design of Lateral Ties Diameter: i) 6 mm minimum ii)
= 8 mm
Provide 8 mm φ ties. Spacing: i) least lateral dimension = 230 mm ii) 16φ = 16 × 32 =512 mm iii) 300 mm Provide 8 mm φ @ 230 mm c/c
Fig. 17 Column No:995
43
9.3 DESIGN OF SLABS 9.3.1 SLAB S1(Fig 18) Size= 3.3m x 9.998m.
Span/d= 30 Cover= 25mm Assume 10 mm bars, eff d= 110mm Overall depth, D= 140mm Eff span= 3410mm=3.41m=lx DL=1 x 1x 0.15 x 25= 3.75 kN/m LL= 3 kN/m TL= 6.75 kN/m Factored load= 10.125 kN/m Factored BM=14.716 kNm Factored SF= 17.30 kN d reqd= 65.31 mm400mm Provide #10 @460 c/c 44
9.4 DESIGN OF STAIRS 9.4.1 MAIN STAIRCASE(Fig. 18)
Thread= 300mm Rise=150mm No of rise= 3/0.15=20 No of rise in each flight= 10 No of threads in each flight=10-1=9 Going=0.3 x 9=2.7m Span= 4.4m Assume 25mm clear cover and 16 mm dia bars Thickness of waist slab= 233mm Total udl= Self wt+wt of waist slab +wt of steps= 12.16 kN/sq.m d reqd= 119.02 mm d provided=233-25-(16/2)=200mm Ast min= (0.12/100)x1000x200=240 sq.mm Ast =575.72 sq.mm Spacing of 16mm dia bars= 349.23mm Provide steel #16@380mm c/c Distribution bar 8mm dia Spacing=209.44mm Provide #8@220mm
45
Fig. 18 Slab and Staircase
46
10. PLANNING AND DESIGN OF FOUNDATION 10.1 INTRODUCTION Proper design of a substructure of a multi-storeyed structure is important for its stability and durability. The major function of substructure is to transmit load from the superstructure uniformly and safely to the strata of soil below it. The type of foundation to be adopted and designed depends on the nature of the load and the supporting soil. The various loads acting on the structure are obtained according to the IS codes and are calculated during load calculation. The soil characteristics required for foundation design-angle of internal friction, standard penetration number, position of water table, and the depth of the refusal stratum, are obtained from Soil investigation report from the proposed site. The foundation is designed to carry a heavy structure as a five-storeyed building with a column beam structure. Considering the safety of the proposed building, deep foundation is provided. Deep foundation can be pile foundation, well foundation or caissons. Pile foundation was found to be the best solution for the load and soil conditions at the site.
10.2 PILE DESIGN THEORY As per the design recommendations, the foundation for the proposed structure is end-bearing piles. Static method for the design of end bearing pile is used. The ultimate bearing capacity (Qu) of the pile at the pile tip can be computed from the bearing capacity equation, Qu = Ap (Pd × Nq + 0.5 × γ × B × Nγ) Where, Ap = area of the pile tip Pd = effective overburden pressure at the pile tip B = lateral dimension of the pile γ
= unit weight of soil
47
Nq, Nγ = bearing capacity factors for deep foundations Bearing capacity factors for the design is obtained from IS 2911:1979 corresponding to the value of angle of shearing resistance and SPT ‘N’ value at the zone of soil at the pile tip. Piles arbitrarily chosen are circular with diameter fixed as the design demands. The critical depth, beyond which lateral earth pressure essentially remains constant, is 15 times pile diameter, which is well below the pile depth. With the SPT ‘N’ value of 100 at the refusal stratum, angle of internal friction φ is read as 43. Bearing capacity factors for this φ value are Nq=109.41, Nγ =206.82. From the six bore log sheets obtained from the site, the worst case, where the soil has the least unit weight, angle of internal friction, etc. was chosen for the design purpose. With this soil data, pile capacities were calculated using Terzaghi’s bearing capacity equation as in equation 45. From the STAAD Pro analysis reports, axial loads for various load cases are obtained, from which the maximum axial load on each column is, selected. Based on this load, the columns are classified into various load groups, each group with a range of 1000 kN. Number of piles under each column is calculated by dividing the maximum axial force on a column by the safe bearing capacity of a single pile. Nodal details and pile groups thus obtained are as tabulated in Table 10. Piles are checked for moment and lateral load. Piles are structurally designed as short columns subjected to axial load and biaxial bending.
10.3 PILE CAPACITY DETERMINATION As mentioned in the abstract, pile capacity is determined by the static pile capacity equation. Circular end bearing piles of 0.7 m and 0.9 m diameter is fixed for every column. The piles rest on a hard stratum 1.5 m below the ground level. Pile capacity, Qu = Ap ( Pd × Nq + 0.5 × γ × B × Nγ) Diameter = 0.9m Assuming capacity of a single pile, Qu = 1280 kN Adopting a factor of safety of 3,
48
Safe bearing capacity = = 420 kN
10.4 PILE GROUP DETERMINATION Number of pile required under each column, i.e. the pile group is determined by dividing the maximum axial force occurring at the column by single pile capacity. For 100% group efficiency, pile spacing in the group is fixed as 2.5 times the pile diameter. STAAD Pro analysis gives the ultimate load for each load case. Pile groups are fixed based on the working loads as shown in the example below. For critically loaded column, Ultimate axial load= 2280.63 kN Working load = =1520.42 kN Number of piles = =4 Thus pile group is fixed as 2 × 2.
Different nodes and pile groups chosen are shown in Table 4
49
Table 4. Pile groups and column classification based on loads Sl.
Load
N
rang
o
e
1
01000
Columns with load coming in that range
Pile
Pile
diamete
grou
r (mm)
p
700
2x2
900
1x1
900
2x2
407, 410, 411, 409, 414, 418, 434, 440, 441, 442, 555, 556, 557, 561, 562, 563, 564, 568, 569, 570, 571, 572,573,574,575,576,577,578,579,580,581,582,583,584
2
1000-
412, 413, 415, 416, 417, 419, 423, 425, 426, 427, 428,
2000
429,432,433,437,438,439,452,453,454,455,456,457,458,459,460,461,46 2463
3
>200
420, 421, 422
0
10.5 ANALYSIS OF PILES Once the pile groups are determined and the nodes falling under the common pile group are found, the maximum axial force (Fy) and the lateral forces (Fx and Fz) are selected from the STAAD Pro analysis report. It is tabulated in Table 5.
Table 5: Maximum axial and lateral loads in a pile group Sl. No
Pile group
Fx (kN)
Fy (kN)
Fz (kN)
1
2x2
2280.630
34.778
14.293
2
1x1
1857.310
31.539
8.375
10.6 DESIGN OF PILES Piles are designed as short column subjected to axial load and bilateral bending. Consider the 2×2 pile group, 90 cm diameter. Design parameters as obtained from the STAAD Pro analysis is taken from Table 5. Maximum axial force = Pu= 2280.63kN
50
Maximum moment in X direction = Mux= 22.572 kNm Maximum moment in Z direction = Mu z= 60.796 kNm Unsupported length = 6m Effective length, leff = 0.7 × 6=4.2 m = 0.7 × =6 Therefore, short column. As per clause 25.4 of IS 456:2000, ex =
= = 9.89 mm
ez = = 26.658 mm
ez min = ex min = = =42 mm Therefore, biaxial bending, Mu = 1.15 √ =1.15 √ = 74.578 kNm.
51
= = 0.05
= = 0.112
= = 0.04 From chart 55 of SP 16. = 0.02 Percentage steel = p =0.5% Asc= Asc min=
=5089.38 mm2 Asc max = =25446.9mm2 Providing 25 mm diameter bars, No: of bars =11 Therefore, provide 11 no’s 25 mm diameter bars. Ascprovided =5400 mm2 = 0.1126 pprovided =0.84% = 0.034 = 0.05
52
=0.06 Mux1= .06 × 25 × 9003 =1093.5 kNm, >> Mux Muz1= 1093.5 kNm >> Muz Check Puz = 0.45fckAc + 0.75fyAsc = (0.45 × 25 × 630772.9) + (0.75 × 415 × 5400) = 8776.945kN Pu = 2280.630kN = = 0.2598 From clause 39.6 of IS 456:2000,
+
=1
= 0.0762 < 1
Hence safe in biaxial bending.
10.7 DESIGN OF TIES Diameter :
i) 6 mm minimum. ii)
= 6.25
Provide 8 mm φ ties. Spacing: i) least lateral dimension =900 mm ii) 16 φ =16 × 25=400 iii) 300 mm Provide 8 mm φ @ 300 mm c/c Abstract of design of piles is shown in Table 6.
53
Table 6: Abstract of design of piles Sl. No 1 2
Pile diameter(mm) 900 700
Main reinforcement 11 nos. 25mm diameter. 7 nos. 25mm diameter.
Lateral ties 8mm @ 300mm c/c. 8mm @ 300mm c/c.
10.8 DESIGN OF PILE CAP Pile caps are provided over pile groups to distribute the load uniformly over the piles. Consider the pile cap for 900 mm diameter, 2 × 2 pile group. Distance between the piles = 2.5 × 0.9 = 2.25m. Pile cap dimension = 2.25 + 0.9 + 0.6 = 3.75 m. Thus pile cap size = 3.75 × 3.75m. Maximum axial load, P = 2280.63kN Moment, Mx = 22.572 kNm Moment, Mz = 60.796 kNm Maximum force on a single pile due to moment and axial force F= =
+
+
kN
= 590.423 kN Bending moment at the critical section of pile cap, M=F ×
kNm = 531.38 kNm
Mu, lim = 0.36 ×
× (1-0.42
) × bd2 fck
531.38 × 106 = 0.36 × 0.48 × (1-0.42 × 0.48) × 1000 × d2 × 40 D = 310.3mm
54
Assuming a clear cover of 80 mm, D= d + 80 = 390.3mm Provide D = 500 mm d= D - 80 = 420mm Mu = 0.87 × fy × Ast × d (1 -
)
= 0.87 × 415 × Ast × 420 × (1-
)
Solving the above equation, Ast= 3875.152mm2 Minimum steel required = 0.12% of gross area = 0.12 × 1000 × = 600 mm2 OK Provide 3875.152 mm2 of main reinforcement. Provide 28 mm diameter bars at 150 mm c/c at the bottom Check for shear Shear force= Vu= 590.423 kN Actual shear stress= τv = = = 1.406N/mm2 = 0.923 Permissible shear stress= 0.655 N/mm2 Strength of shear reinforcement = Vus= Vu- τcbd =590230 - 0.655 × 1000 × 420
55
= 315130 N/mm2. Spacing of 6 legged 12 mm diameter stirrups: Vus= 0.87 × fy ×Asv × 315130 = 0.87 × 415 × 678.584 × Sv=326.54 mm Provide 6 legged 12 mm diameter bars as shear reinforcement @ 300 mm c/c. Check for punching shear Punching shear stress = = 162.178 kN/m2 Punching shear force= 162.178 × (3.752 -
)
=2177.455 kN Allowable punching shear stress = = = 4 N/mm2 Consider the critical section for shear at distance d from the face of the column. Thus critical section is a circular section of diameter 1.82 m. Allowable punching shear stress = 4= Dreqd = 95.208mm Where, Dreqd is the gross depth required to take punching shear force Dprovided = 500mm Hence safe against punching failure
56
Abstract of pile cap design is shown in Table 7 Table 7: Abstract of pile cap design Sl. No
Pile cap dimension ( m)
Main reinforcement
1
3.75 x 3.75 x 0.5
28mm φ @ 150 mm c/c
2
3.05 x 3.05 x 0.5
25mm φ @ 150 mm c/c
Shear reinforcement 6 legged 12 mm φ stirrups @ 300mm c/c 6 legged 8 mm φ stirrups @ 300mm c/c
The reinforcement details of the typical structural elements are shown in Fig.
57
58
11. CONCLUSION The aim of our project was planning, analysis and design of a multi-storeyed, earthquake resistant residential building. We were able to complete the project in a successful and efficient manner by considering all the relevant features given as nine chapters. Planning of this building has been done based on the space requirements suggested by the prevailing rules stipulated in Kerala Building Rules, 1999. The design is completely based on relevant Indian Standard Codes. The analysis has been done with the help of STAAD Pro and the drawings have been made with the help of AutoCAD. We have completed this project to the best of our knowledge and ability.
59
12. REFERENCE
The references that will be referred to for this project work are: o Bye-laws In Planning-KMBR, 1999 o Design Codes IS 456:2000 IS 875 (Part 2):1987 (Reaffirmed 1997) IS 875 (Part 3):1987 (Reaffirmed 1997) IS 1893 (Part I):2002 IS 2911 (Part 1-4):1979 (Reaffirmed 1997) IS 4326:1993 IS 13920:1993 (Reaffirmed 1998) IS 13935: 1993 o Software STAAD Pro o Books Design of RCC Structures by B. C. Punmia Limit State Design of Reinforced Concrete by P. C. Varghese Reinforced Concrete Design by S. N. Sinha Reinforced Concrete Limit State Design by Ashok K Jain Basic & Applied Soil Mechanics by Gopal Ranjan & A. S. R. Rao Geotechnical Engineering by K. R. Arora
60
