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DEPARTMENT CIVIL ENGINEERING
N.W.F.P. UNIVERSITY OF ENGINEERING & TECHNOLOGY PESHAWAR
DESIGN OF ACADEMIC BLOCK, CASE STUDY
SUPERVISED BY:
ENGR. FAISAL UR REHMAN
SUBMITTED BY: BILAL AKBER
HUMAIRA MANSOOR AHMAD ABDI HASSAN
Session 2008
DEPARTMENT CIVIL ENGINEERING
N.W.F.P. UNIVERSITY OF ENGINEERING & TECHNOLOGY PESHAWAR
DESIGN OF ACADEMIC BLOCK, CASE STUDY
SUPERVISED BY:
ENGR. FAISAL UR REHMAN
SUBMITTED BY: BILAL AKBER
HUMAIRA MANSOOR AHMAD ABDI HASSAN
Chairman Adviser
Prof. Dr. Akhtar Naeem Engr. Faisal-ur-Rehman
-------------------------- ------------------------
DIDICATIONSDIDICATIONSDIDICATIONSDIDICATIONS
DedicatedDedicatedDedicatedDedicated ToToToTo ourourourour
BELOVED PARENTSBELOVED PARENTSBELOVED PARENTSBELOVED PARENTS
After ALLAHAfter ALLAHAfter ALLAHAfter ALLAH
Who, with their very limitedWho, with their very limitedWho, with their very limitedWho, with their very limited Resources,Resources,Resources,Resources,
Provided us every thingProvided us every thingProvided us every thingProvided us every thing
That enabled us to reach at this pointThat enabled us to reach at this pointThat enabled us to reach at this pointThat enabled us to reach at this point
And complete the project workAnd complete the project workAnd complete the project workAnd complete the project work
And to all Our teachers Who Guide usAnd to all Our teachers Who Guide usAnd to all Our teachers Who Guide usAnd to all Our teachers Who Guide us
And Teach SincerelyAnd Teach SincerelyAnd Teach SincerelyAnd Teach Sincerely....
ACKNOWLEDGMENT
First of all we would like to express our deepest gratitude to Almighty and
Merciful Allah, Who gives us the power to do, the sight to observe and mind to
think, judge and analyze. We were not able to perform and face this task, but it
was He Who gives us the courage, power and ability.
We are paying special thanks to our punctual, kind, cooperative, hardworking
and ingenious supervisor Engr. Faisal ur Rehman for his occasionally and
constantly Guidance, Encouragement, Supervision and help that enable us to
complete our Final Year Project.
It was a very beneficial and practical experience for us to learn the modern
techniques of designing efficient irrigation channel and use of modern software
relating designing of watercourses and canals
Finally, we are thankful to our beloved parents for encouraging and morally
supporting us for the completion of our study work.
Contents
Abstract ............................................................................................................................... 1
Chapter 1 Literature Review ............................................................................................... 2
Introduction ..................................................................................................................... 2
Types of Analysis ........................................................................................................... 2
Cycle of Structural Analysis and Design ........................................................................ 3
Chapter 2 Analysis, Loads and Softwares .......................................................................... 4
Response Spectrum Analysis .......................................................................................... 4
Time History Analysis .................................................................................................... 4
Softwares Used ............................................................................................................... 4
Etabs ............................................................................................................................ 5
SAP 2000 V. 11 .......................................................................................................... 5
Safe ............................................................................................................................. 5
Chapter 3 Methodology ...................................................................................................... 6
Steps Followed for Analysis and Design in Etabs .......................................................... 6
Layout ............................................................................................................................. 6
Modeling ......................................................................................................................... 6
Material Properties .......................................................................................................... 6
Concrete ...................................................................................................................... 6
Steel............................................................................................................................. 6
Brick ............................................................................................................................ 7
Soil Pressure................................................................................................................ 7
ACI – 318-02 .................................................................................................................. 7
Load Factors.................................................................................................................... 7
Structural Elements ......................................................................................................... 7
Loads ............................................................................................................................... 7
Earthquake Loads UBC 97 ............................................................................................. 8
Earthquake Loads UBC Response Spectrum Analysis (RSA) ....................................... 8
Load Cases (RSA)....................................................................................................... 8
Define Piers and Spandrels ............................................................................................. 9
Analysis of Walls ............................................................................................................ 9
Design of Shear Wall and Core Wall .............................................................................. 9
Check Demand / Capacity Ratio ..................................................................................... 9
Brick walls can be used for Brick Masonry Performance in Earthquake Resistant
Building........................................................................................................................... 9
Retaining Wall .............................................................................................................. 10
Ramp ............................................................................................................................. 10
Stairs ............................................................................................................................. 10
Import the model from Etabs ........................................................................................ 10
Detailing and Structural Drawings................................................................................ 10
Define GAP element (Links element)........................................................................... 10
Time History Analysis .................................................................................................. 11
Chapter 4 Results and Comparison ................................................................................... 12
Chapter 5 Observation, Conclusion and Recommendations............................................. 14
Observation ................................................................................................................... 14
Conclusions ................................................................................................................... 14
Recommendations ......................................................................................................... 14
Reference ...................................................................................................................... 14
Appendix ........................................................................................................................... 15
Design of Academic Block, Case Study
1
ABSTRACT
Earthquake analysis of Acedemic Block N-W.F.P UET Peshawar was carried out using
UBC97, Time History and Response Spectrum Analysis. ETABS and SAFE were used
for analysis and design.
It was observed that ratio of Beam to Column x-section is very high i.e., large beam
section w.r.t small column sections. Also the ratio of Length of Beam to that of Column
is very high. This creates a problem of resisting more moment by beam instead of
transferring effectively to columns.
It was concluded that The Building is designed for damage limit state. Steel of our
analysis is less than actual steel used. Less steel is because we have included Brick
Masonry in analysis so the structure is more stiff in spite of earthquake forces.
It is recommended that the model should be also designed for Time History Analysis.
Pounding Action at expansion joint should be observed by using nonlinear GAP element.
Forces need to be check at different time steps.
Keywords: Time History Analysis, Response Spectrum Analysis, UBC97 Earthquake
Analysis, Brick Masonry Modeling, Shear Wall Modeling.
Design of Academic Block, Case Study
2
CHAPTER 1 LITERATURE REVIEW
INTRODUCTION
The basic job of a Structure Engineer is to know the available tools and materials and
employ those tools to make economical structures, which can resist and withstand by
natural forces.
The case study of Academic Block is not just analysis and design but it is about studying
different methods and techniques. These techniques enable us to analyze and design
frame, slabs, footing, stairs, shear wall, confined brick masonry and retaining walls.
The Academic block is situated on Road-2 adjacent to Mechanical Engineering
Department N-W.F.P University of Engineering and Technology Peshawar.
The project of Academic Block was started in 2006. The consultant is Naveed Aslam &
Associates Islamabad while the contractor is Nawab Brothers Karachi. The client is
N.W.F.P University of Engineering and Technology, Peshawar.
The building is concrete frame of five stories with basement. The building is a
symmetrical about its transverse axis and divided into three blocks. Two blocks are
symmetrical while third block separates them. There is expansion-joint between the
blocks to cope with soil settlement.
As discussed in the start of chapter, aim of Structural Engineer is to design a structure
that is economical, sound in architecture and fulfill its purpose.
TYPES OF ANALYSIS
Analysis means finding axial, shear , moment and displacement in the structure.
Design of Academic Block, Case Study
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The two basic methods for structural analysis are Force and Displacement. The word
“Force” represents all applied and resisting load like axial, shear, bending moment and
torsion. Similarly the word “Displacement” includes deflection, rotation and settlement.
In force method, the primary unknown is Force. For finding theses forces different
methods were developed. After finding forces we find the displacement. Examples are
Unit Load Method, 03 Moment Equation, Virtual Work Method and Direct Flexibility
Method. In contrast to Force Method, Displacement is the primary unknown in
Displacement Method, from which forces are calculated. Different displacement methods
are Slope Deflection Method, Moment Distribution Method, Direct Stiffness Method.
CYCLE OF STRUCTURAL ANALYSIS AND DESIGN
Following is the cycle for Structural Analysis and Design:
1. Analysis of Structure: We solve structure using either force or displacement method
to find axial, shear, moment and displacements.
2. Design of Structure: Based on given forces and displacements which comes after
analysis, we find the appropriate dimenstion of structural cross section and the
amount of steel required.
3. Detailing of Structure: We make drawings containing dimension of structural
elements like beam, column and slabs as well as the required amount of steel.
Design Code: It is the guideline for Design Engineer to choose the appropriate
dimension and steel amount which is safe enough to withstand the forces of nature.
Available Softwares : There are many softwares available in market for analysis and
design of structures. Some of them are opensource and available for free like excel spread
sheets, opensees( a finite element analysis solver) while other are properiety softwares
like SAP2000 and STAAD Pro.
Design of Academic Block, Case Study
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CHAPTER 2 ANALYSIS, LOADS AND
SOFTWARES
UBC 97 Earthquake Loads: It is the equivalent static laod of earthquake applied on
structure at floor levels. It is found from the ratio of givend floor weight to the total
weight of the structure multiplied by the given base shear. Base shear is fixed from
Earthquake Zone, Importance factor, Ductility factor, and Time Period factor
RESPONSE SPECTRUM ANALYSIS
It is method of finding base shear from:
1. Ca and Cv
2. and from Time Period of the structure.
using ubc97 response spectrum curve envelope.
This base shear is then distributed at floor levels as a proportion of the floor weight to the
total weight.
TIME HISTORY ANALYSIS
It is the method of finding earthquake force at each time step from the input of
acceleration time history of given earthquake.
SOFTWARES USED
For this project, ETABS (Extended 3D Analysis of Building Systems), SAFE (Slab and
Foundation Analysis Using Fininte Element Method), SAP2000 (Structural Analysis
Program) and Excel sheets are used.
Design of Academic Block, Case Study
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Etabs Etabs is chosen for analysis and design as it is made specifically for buildings. There are
built-in tempaltes for building systems. Furthermore it is very easy to analysis and design
shear walls in Etabs.
SAP 2000 V. 11 Sap2000 is a general purpose finite element program. It was used just only to explore the
feature of import from Etabs. The solver of SAP2000 is much more faster the etabs hence
it analyzes the structure quickly.
Safe SAFE is used to find the detailing drawings of beams and foundations as well as to find
the quatity estimate.
Design of Academic Block, Case Study
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CHAPTER 3 METHODOLOGY
STEPS FOLLOWED FOR ANALYSIS AND DESIGN IN ETABS
The Building Model in Symmetrical model about longitudinal axis. Two symmetrical
portions are separated by Middle block with Expansion Joint 2” wide.Right Half Portion
contains Stair well while Left Half Portion contains Core Wall for lift
LAYOUT
1. Formation of Grid line of Right Half Portion
2. Beams, Columns and Slab
3. The section of Beams along x- direction is ConcBeamX (18”x12”) while that
along y-direction is ConcBeamY (27”x12”)
4. All columns are 24”x12”
5. Slab is 6” thick
MODELING
Beams and Columns were modelled as Line Element. Slab, foundation and Shear Walls
as modeled as Area Element (Shell) while Brick Masonry wall was modelled as line
element as well as Area Element (Shell).
MATERIAL PROPERTIES
Concrete 1. Modulus of Elasticity, E = 3600 ksi
2. Compressive Strength, fc’ = 3ksi
3. Unit weight = 0.15 ksf
Steel 1. Yield Strength (Longitudinal bars), fy = 60ksi
2. Yeild Strength (Stirrup), fs = 60 ksi
Design of Academic Block, Case Study
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Brick 1. Unit weight = 0.12 ksf
2. Modulus of Elasticity = 240 ksi
3. Compressive Strength = 600 psi
Soil Pressure 1. Allowable Soil Pressure, qa = 5 ksf
ACI – 318-02 LOAD FACTORS
1. Dead Load = 1.2
2. Live Load = 1.6
3. Moment = 0.9
4. Shear = 0.75
STRUCTURAL ELEMENTS
1. Beam and Columns as Line Element
2. Brick masonry, Shear Wall, Slab and Foundation as Shell Element
3. Stairs and Ramp as Shell
LOADS
1. Self Weight (Program Calculated)
2. Super Imposed Dead Load (DL)
3. 0.036 ksf
4. Live Load (LL)
5. Ground Floor = 0.1 ksf
6. Intermediate Floors = 0.08 ksf
7. Top Roof = 0.03 ksf
Design of Academic Block, Case Study
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EARTHQUAKE LOADS UBC 97
1. UBC –97 Auto Lateral
2. Two load Cases EQX and EQY were defined
3. Soil Profile Type = SD
4. Seismic Zone Factor = 0.2
5. Ca = 0.28 (program Calculated)
6. Cv = 0.24 (program Calculated)
7. Time Period factor , C(t) = 0.03 (for Concrete frames)
8. Over Strength Factor = 5.6, for Building Frame System and Ordinary Braced
Frame Concrete
9. Importance Factor, I = 1
10. Eccentricity of Resultant of lateral force = 5%
EARTHQUAKE LOADS UBC RESPONSE SPECTRUM ANALYSIS
(RSA)
1. Function = UBC 97 Spectrum (User Defined)
2. Function name = RS
3. Ca = 0.28
4. Cv = 0.24
5. Function is adjusted for the maximum ordinates of acceleration so that the time
period of our structure lies in Peak Acceleration
Load Cases (RSA) 1. RSX
2. Function = RS
3. Scale factor = 386.4 (g in inches)
4. Direction = U1 (for x-axis)
Design of Academic Block, Case Study
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5. Eccentricity of Resultant force = 5%
6. Damping = 5%
7. RSY
8. Same as RSX but Direction = U2
9. Load Combination (Program Calculated)
DEFINE PIERS AND SPANDRELS
The wall portion were selected and vertical members were defined as pier while
horizontal members were defined as spandrals.
ANALYSIS OF WALLS
After analysis of walls integrated into whole structural system, shear forces were
observed in piers and spandrals. The shear force for wall is shown as that of line element.
Minimum and maximum shear in piers were calculated.
DESIGN OF SHEAR WALL AND CORE WALL
Based on analysis result, software showed the steel required in each wall.
CHECK DEMAND / CAPACITY RATIO
Based on analysis result, software showed the Demand/Capacity ratio in each wall. All
demand capacity ratio were less then 1 means the capacity of shear wall is ok.
BRICK WALLS CAN BE USED FOR BRICK MASONRY
PERFORMANCE IN EARTHQUAKE RESISTANT BUILDING
The effect of masonry wall was also considered into account. Masonry wall was firstly
modeled as line element cross bracer then it was modeled as shell element. For linear
analysis, the shell element gives better results for design.
Design of Academic Block, Case Study
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RETAINING WALL
Walls at Basement were designed as both Shear Wall and Retaining Wall
Retaining Wall is designed by Excel Sheet using ACI-318-02
RAMP
Ramp is designed for LL of 500 psf
STAIRS
There are two types of Stairs in Building:
1. Stair Slab Spanning Horizontally
2. Stair Case Spanning Longitudinally
3. Stairs were also design using Excel Spreadsheet
IMPORT THE MODEL FROM ETABS
Model from Etabs was imported to SAP2000 and SAFE. In SAP2000, the model was
only imported to have a cross check on analysis of etabs. The results were matching. In
SAFE the Analysis for Slab and Foundation was carried out.
DETAILING AND STRUCTURAL DRAWINGS
After analysis in SAFE, Detailing Drawings were generated as well as quatity estimate of
rebars was calculated.
DEFINE GAP ELEMENT (LINKS ELEMENT)
There is an expansion joint of 2 inches. It was modeled for a study perpose using the
GAP element. In main analysis, gap element was not considered.
Design of Academic Block, Case Study
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TIME HISTORY ANALYSIS
1. The time history analysis was carried out:
2. For Pounding Action
3. For Forces and Displacement
4. Video for Time History and pounding Action
Design of Academic Block, Case Study
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CHAPTER 4 RESULTS AND COMPARISON
The detailing drawing of typical beam is shown below:
Rebars
Column
Design As per Actual
Bars = 8#7 + 4#6 - As = 6.5 sq. in Bars = 6#8 + 6#6 - As = 7.38 sq. in
Stirrup = #3 @ 12" c/c Stirrup = #6 @ 6" c/c
Beams
Beam along x - axis
Corner Edge Mid Contin Edge Corner Edge Mid Contin Edge
Top 2#8 2#8 2#8 Top 3-#6 + 3#8 3-#6 + 3#8 3-#6 + 3#8
Bottom 4#8 4#8 4#8 Bottom 3-#6 + 3#8 3-#6 + 3#8 3-#6 + 3#8
Stirrup # 3 @ 7" c/c Stirrup #3 @ 6"c/c
Design As per Actual
Beam along Y - axis
Corner Edge Mid Contin Edge Corner Edge Mid Contin Edge
Top 2#8 - 1.58 2#8 2#8 Top 6-#6 - 2.48 3-#6 6-#6
Bottom 2#7 - 1.20 2#7 2#7 Bottom 3-#6 - 2.64 3-#6 3-#6
Stirrup # 3 @ 7" c/c Stirrup #3 @ 6"c/c
Design As per Actual
Slab
Corner Edge Mid Contin Edge Corner Edge Mid Contin Edge
x #3 @ 6" c/c #3 @ 6" c/c #3 @ 6" c/c x #3 @ 6" c/c #3 @ 6" c/c #3 @ 6" c/c
y #3 @ 6" c/c #3 @ 6" c/c #3 @ 6" c/c y #3 @ 6" c/c #3 @ 6" c/c #3 @ 6" c/c
Design As per Actual
Design of Academic Block, Case Study
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Shear Wall at Basement
Design As per Actual
Bars along the height =#3 @ 5" c/c Bars along the height = #3 @ 3" c/c
Bars along the length =#3 @ 12" c/c Bars along the length = #3 @ 8" c/c
Core Wall
Design As per Actual
Bars along the height =#4 @ 11" c/c Bars along the height = #4 @ 6" c/c
Bars along the length =#3 @ 12" c/c Bars along the length = #3 @ 8" c/c
Design of Academic Block, Case Study
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CHAPTER 5 OBSERVATION, CONCLUSION AND
RECOMMENDATIONS
OBSERVATION
1. Ratio of Beam to Column x-section is very high i.e., large beam section w.r.t
small column sections.
2. Ratio of Length of Beam to that of Column is very high. This creates a problem
of resisting more moment by beam instead of transferring effectively to
columns
3. In modern design, Cracks are avoided in Column but above criteria makes the
column more severe to cracks
CONCLUSIONS
1. The Building is designed for damage limit state.
2. Steel of our analysis is less than actual steel used.
3. Less steel is because we have included Brick Masonry in analysis so the
structure is more stiff in spite of earthquake forces.
RECOMMENDATIONS
1. The model should be also designed for Time History Analysis.
2. Pounding Action at expansion joint should be observed by using nonlinear GAP
element
3. Forces need to be check at different time steps.
REFERENCE
1. Reference Manual of ETABS, SAP2000, and SAFE
2. UBC97 Design Code
3. ACI 318-02 Design Code
4. Brick masonry infills in seismic design of RC framed buildings: Part 1 Cost
implications by Diptesh Das and C.V.R. Murty
Design of Academic Block, Case Study
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APPENDIX
Limit States:
� Serviceability Limit State
� 50% probability of the design Earthquake
� Cracks need no repair
� Return period of that earthquake = 72 years
� Drift = 0.5 %
� Bricks are intact
� Damage Control Limit State
� 10% probability of the design Earthquake
� Cracks need repair but should have less cost
� Return period of that earthquake = 475 years
� Drift = 2%
� Survival Limit State
� 10% probability of the design Earthquake
� Damage beyond repair
� Return period of that earthquake = 2500 years
� Drift = 2%
� SD = Stiff soil with shear wave velocity of 600 to 1200 ft/sec
Design of Academic Block, Case Study
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Model of Acedemic Block in Etabs
Design of Academic Block, Case Study
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Views of Acedemic Block: