ANALYSIS & DESIGN OF G+3 STORIED REINFORCED CONCRETE BUILDING Guide: Prof. Sanjaya Kumar Patro Presented by: Abhilash Chandra Dey

Presentation outline Aim of the project Requirements of Design of RC building Steps in Design of RC Buildings Methodology Limit State Design Seismic Analysis Drawings of the Building for this project work Procedure of Design Discussion of results Conclusion

Aim of the project Carrying out a complete analysis and design of the main structural elements of a multi-storey(G+3) building including slabs, columns. Getting familiar with structural software's ( Staad Pro ,Staad Foundation, AutoCAD) The aim of the project is to plan and design the framed structure of a residential building and compare with the design by Staad Pro. Designs will be as per following codes: 1. Indian Standard Plain and Reinforced Concrete code of Practice. IS 456: 2000 2. IS:875(1987) code of practice for design loads 3. IS:1893(2002), Indian Standard Criteria for Earthquake Resistant Design of structures 4. IS:13920(1993), Ductile Detailing Of Reinforced Concrete Structures Subjected to seismic forces

Requirements of Design of RC building Selection of Good Structural System to Resist Gravity, Wind & Seismic Forces Proper Analysis and Design Good Detailing Quality Construction

Steps in Design of RC Building Structural System Preliminary Analysis Proportioning members Detailed Analysis Evaluation

Structural Requirements Resistance required to protect against Shear Failure Flexural Failure Axial Failure

Indian Codes and Standards Codes used in Earthquake-Resistant Design of Reinforced Concrete Buildings IS 456 : 2000 IS 875 : 1985 Parts I, II & V IS 1893 : 2002 Part I IS 13920 : 1993

Limit State Design A structure is considered to have reached its limit state, when the structure as a whole or in part becomes unfit for use, for one reason or another, during its expected life Various Limit States Collapse – Failure modes Serviceability – Deflections and Drifts Durability – Crack width and permeability control

Partial Safety Factors for Loads AS PER IS:456 Limit State of Collapse Load Combination DL IL EL/WL DL + IL 1.5 - DL + IL  EL 1.2 DL  EL 0.9*

Limit State of Serviceability (Short-term effects) Load Combination DL IL EL/WL DL + IL 1.0 - DL + IL  EL 0.8 DL  EL

Load Combinations: 1893 Requirements Only one component of earthquake ground motion need be considered at a time For limit state of collapse, the following load combinations should be considered 1.5 DL + 1.5 IL 1.5 DL ± 1.5 ELx 1.5 DL ± 1.5 ELy 1.2 DL + 1.2 IL ± 1.2 ELx 1.2 DL + 1.2 IL ± 1.2 ELy

Load Combinations: 1893 Requirements For overturning, the following load combinations should be considered 0.9 DL ± 1.5 ELx 0.9 DL ± 1.5 ELy One needs to establish the member design forces (axial force, shear, bending moments) for earthquake along x-axis (ELx) and for earthquake along y-axis (ELy) separately to combine them with forces obtained for DL and IL analyses

LOAD COMBINATION USED IN THIS PROJECT For gravity load case: Load combination 4= 1.0(DL+LL) Load combination 5= 1.5(DL+LL) For Zone ii, zone ii, Zone iv, Zone V: Combination load case 6: 1.0(DL+LL) Combination load case 7: 1.0(EQX+0.3EQZ +1.0DL+0.25LL Floor) Combination load case 8: (-1.0EQX+0.3EQZ +1.0DL+0.25LL Floor) Combination load case 9: (0.3EQX+1.0EQZ +1.0DL+0.25LL Floor) Combination load case 10: ( 0.3EQX -1.0EQZ +1.0DL+0.25LL Floor)

Combination load case 11: 1.5(DL+LL) Combination load case 12: (1.0EQX+0.3EQZ +1.0DL+0.25LL Floor)*1.2 Combination load case 13: (-1.0EQX+0.3EQZ +1.0DL+0.25LL Floor)*12 Combination load case 14 : (0.3EQX -1.0EQZ +1.0DL+0.25LL Floor)*1.2 Combination load case 15: (0.3EQX+1.0EQZ +1.0DL+0.25LL Floor)*1.2 Combination load case 16: 1.5(EQX+0.3EQZ+1.0DL) Combination load case 17: 1.5(-EQX+0.3EQZ+1.0DL) Combination load case 18: 1.5(0.3EQX+1.0EQZ+1.0DL) Combination load case 19: 1.5(0.3EQX-1.0EQZ+1.0DL)

Seismic Analysis Procedures Seismic Coefficient Method (SCM) Equivalent Static Forces Response Spectrum Method (RSM) Modes Shapes and Modal Participation Time-History Analysis (THA)

Seismic Coefficient Method Effects of earthquake are considered as equivalent lateral forces Design seismic base shear The design base shear is the sum of lateral forces applied at all levels that are finally transferred to the ground

SCM – Zone Factor Z is the zone factor: the value of peak ground acceleration given in the units of ‘g’ for the maximum considered earthquake The value Z/2 corresponds to design basis earthquake – damage control limit state Based on the history of seismic activities and seismo-tectonic understanding, the entire country has been divided into four zones, and the Z values are: 0.36 for zone V, 0.24 for zone IV, 0.16 for zone III, and 0.10 for zone II (Table 2, IS 1893: 2002)

Seismic Zoning Map (IS1893 : 2002)

SCM – Response Factor R R is the response factor and controls the permitted damage in design basis earthquake The minimum value of R is 3 and maximum is 5. However, to use higher values of R, special ductility detailing requirements are a must and the designer is accepting more damage but in a controlled manner (Table 7, IS 1893 : 2002)

SCM – Importance Factors I is importance factor and permitted damage could be reduced by setting the value of I more than 1 For buildings like hospitals, communication and community centers, the value is 1.5 (Table 6, IS 1893 : 2002) R/I together defines permitted damage

SCM – Soil Classification Sa is the spectral acceleration to be established in m/sec2 or Sa / g as dimensionless value For 5 percent damping, three different curves are recommended in IS 1893 : 2002 for different stiffness of supporting media – rock, medium soil and soft soil The classification of soil is based on the average shear wave velocity for top 30m of rock/soil layers or based on average Standard Penetration Test (SPT) values for top 30m (Table 1, IS 1893 : 2002) Detailed geo-technical investigations are required to classify soil type

SCM – Soil Classification Class I – Rock or Hard Soil: Well graded gravel and sand gravel mixture with or without clay binder having Corrected Standard Penetration Value N > 30 Class II – Medium Soil: All soils with N between 10 and 30 or gravelly sand with little or no fines (classification SP) with N > 15 Class III – Soft Soil: All soils other than SP with N < 10

SCM – Time Period of Building The spectral acceleration Sa is a function of the Fundamental Time Period of the Structure For RC framed building without brick infill panels, the Time Period in seconds may be estimated as where h is height of building in meters

SCM – Time Period of Building The spectral acceleration Sa is a function of the Fundamental Time Period of the Structure For all other buildings, including moment resisting frame building with brick infill panels, the Time Period may be estimated as in which d is the base dimension of building in meters at plinth level along the direction of ground motion

SCM – Seismic Weight We is the effective seismic weight of the building measured in Newtons Seismic weight includes all Dead Loads (that of floor slabs, finishes, columns, beams, water tanks, permanent machines etc.) Seismic weight includes only part of Imposed loads, for example 25 - 50 % of imposed load for buildings (Table 8, IS 1893 : 2002) and no live load on roof Imposed load used in design are not mean loads but characteristic loads Only a part of inertia forces due to imposed loads can be transferred to the resisting elements One needs to calculate participating weight floor-wise as well as its distribution on the floor

SCM – Equivalent Lateral Forces The equivalent lateral forces are computed from total base shear assuming parabolic deflected shape (or parabolic distribution of lateral forces) In this expression, Wi is the seismic weight for the i-th floor and hi is the height of the floor measured from the base (plinth level) The force fi is the resultant of inertia forces at i-th floor

Equivalent Lateral Forces along Height W4 f4 f3 W2 f2 h4 f1 h2 VB

DESIGN PROCESS FOR THE PROJECT PREPARATION OF STRUCTURAL PLAN NUMBERING AND NOMENCLATURE FOR MEMBERS DESIGN FOR GRAVIT LOAD SOFTWARE MANUAL ANALYSIS OF FAILURE IN DESIGN WITH SEISMIC FORCES DESIGN FOR SAFE STRUCTURE

Drawings of the Building for this project work Architectural Plan & Elevation

STRUCTURAL PLAN Floor Plan Roof Plan

NUMBERING AND NOMENCLATURE Numbering of Beam & Column

Staad-pro MODAL views

3-D MODEL BY STAAD-PRO Before After

AXIAL LOADS IN COLUMN ( GRAVITY LOAD ) Column No. TOP STOREY Pr (KN) 3rd STOREY Pr+Pf (KN) 2nd STOREY Pr+2Pf (KN) 1st STOREY Pr+3Pf (KN) PLINTH Pr+3Pf +PP (KN)   Hand Calc. Staad C14 181 169.433 511 453.315 841 735.429 1171 1020 1325 1170 C7 101 104 292 303.916 483 503.414 674 706.117 800 852.558 C13 50 54.42 168 169.82 286 285.27 404 400.542 490 495.655 C15 281 278.494 532 520.989 783 766.924 1034 1182 C19 54 51.349 194 180.459 334 310.215 474 441.850 562 532.336 C21 66 60.517 219 204.970 372 350.843 525 500.211 627 604.470 C22 162 155.841 491 482.208 820 806.089 1149 1130 1316 1300 C23 322.842 644 587.939 916 862.873 1188 1140 C27 36 42.947 127 142.668 218 241.906 309 340.663 385 426.148 C28 41 40.052 123 147.465 205 250.920 287 354.343 360 438.851

Reaction in vertical direction at foundation level Column nos. Gravity load ZONE II (Kn) ZONE III (Kn) ZONE IV (Kn) ZONE V (Kn)   Kn OMRF SMRF 13 229.271 641.455 564.394 757.048 633.749 911.172 726.224 1142.358 864.935 14 666.280 1172.756 15 694.341 1264.153 1183.887 1397.866 1255.239 1576.149 1362.209 1843.575 1522.664 19 324.336 585.778 546.029 645.403 581.803 724.902 629.503 844.150 701.052 21 368.960 765.260 680.478 892.431 756.781 1061.993 858.519 1316.337 1011.125 22 764.558 1306.692 23 814.883 1696.833 1506.922 1981.700 1677.842 2361.522 1905.736 2931.258 2247.576 27 264.126 584.173 508.920 697.052 576.648 847.557 666.951 1073.316 802.406 28 270.490 634.688 543.050 772.145 625.524 955.421 735.490 1230.335 900.438

concrete quantity by staad output result SL. No Gravity load ZONE II(M3) ZONE III(M3) ZONE IV(M3) ZONE V(M3) Safe structure OMRF 104.4 74.3 57.4 45.1 28.2 331.8 SMRF -- 69.5 62.5 52.3 33.8 311.6 Steel quantity by staad output result SL. No Gravity load(Newton) ZONE II(Newton) ZONE III(Newton) ZONE IV(Newton) ZONE V(Newton) Safe structure OMRF 91196 98292 79097 69675 42267 409014 SMRF -- 79177 76673 68737 44374 261917

DESIGN OF FOOTING FOR SAFE STRUCTURE Combination Of Single & Combined footing Single Footing

DISCUSSION OF RESULTS By comparison of the axial load in gravity load case it is found that load calculated in manual calculation there is variation in between Staad-pro results. By comparing the maximum bending moment and shear force in column and beams it is found that staad-pro result is more reliable then manual calculation. Staad-pro results are more then manual Reinforcement design is purely based on bending moment and axial load for column and bending moment and shear force in beam as there is very large increase of forces in members & the section are chosen by considering the gravity load case. Larger cros-section and reinforcement required for Higher seismic zones for design of safe section. Bending moment , Shear force, Axial force and Reaction at foundation level increases with increase in Zone number and for OMRF case it is greater value calculated by Staad-pro Footing member calculated by staad-pro is larger and having more reinforcement than manual design. For higher load in seismic zone in Re-entraint corner requirement of footing section is very high.

Conclusion Using of commercial structural design Softwares is economic and more reliable for analysis and design of structure.these are user friendly and less time taking. Irregularity in plan and re-entraint corner should should no be provided. OMRF casa design is more critical than SMRF for a structure A structure should be designed for a combination of Gravity load with Seismic or wind load as per codal provision.

Thank you