Design and analysis of reinforced concrete multistory commercial building using ACI 318-08 by robot structural analysis and by manual method

DESIGN & ANALYSIS OF REINFORCED CONCRETE MULTI-
STORY COMMERCIAL BUILDING USING ACI-318
MUHAMMAD ABDUL AZEEM BAIG
IMBIA ABD-EL-SALAM IMBIA AMMAR
A Thesis submitted in
Partial Fulfilment of the requirement for the award
Of the Degree of Bachelors of Civil Engineering
Faculty of Civil Engineering
University Of Bani-Walid Libya
SEPT 2016

ii
I hereby declare that the work in this project report is my own except for quotations
and summaries, which have been duly acknowledged
Student : MUHAMMAD ABDUL AZEEM BAIG
: IMBIA ABD-EL-SALAM IMBIA AMMAR
Date : SEPTEMBER 2016
Supervisor : Prof Dr Ibrahim Mohamed Elhaj

iii
For my beloved mother and Father

iv
ACKNOWLEDGEMENT
First, I would like to thank Almighty Allah for giving me faith, health and
intellectual capacity to carry out this project work. Then, I fully appreciate the moral
support and encouragement from my parents and other family members towards the
course of this study, thank you and may ALLAH (S.W.A) bless you with his infinite
mercy.
It has been a good fortune for me to have Dr Ibrahim Mohamed Elhaj as my
research supervisor, thank you sir; actually, there is no amount of words that i could
use to describe my profound gratitude to you.
I am also grateful to all the teaching staff who offered their contribution
during the conduct of this project. Finally, I am grateful to all my friends and
colleagues, those that were at University of Bani walid & at University of sirte,
students and others that were schooling at other universities.

v
ABSTRACT
All the building structures have to design based on the relevant code of practice of standard.
The choice of the standard code to be applied varies and sometimes depends on the
requirement of the local authority or familiarity of the designers. Standard code is essential in
the reinforced concrete structures design to provide a safety and economic design. Currently,
BS 8110 and ACI-318 are the most widely used standards in designing reinforced concrete
structures based on limit state principle. However, some of the design requirements such as
partial safety factors, material properties, load combinations, etc. Are made to be different
between BS 8110 and ACI-318. This may affect the cost of building structures that were
designed using these two standards. The aim of this study is to design the reinforced concrete
structures for a three-storey commercial building, which will be designed using ACI-318. The
material properties such as characteristics strength of reinforcements and concrete, and
dimensions of the structure elements are fixed. Autodesk Robot Structural Analysis is the
reinforced concrete structure design package that will be used to design and produce the
structural detailing for the three-storey building based on ACI-318. So then, generally, the
study found out that the correctly designed structure may result in economical output while
ensuring safety.

vi
CONTENTS
DESIGN & ANALYSIS OF REINFORCED CONCRETE MULTI-STORY
COMMERCIAL BUILDING USING ACI-318 i
OATH ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
CONTENTS vi
LIST OF TABLES xi
LIST OF FIGURES xv
LIST OF APPENDICES xi v

vii
CHAPTER 1 -
INTRODUCTION 1
1.1 Research Background 1
1.2 Problem statement 2
1.3 Objectives 3
1.4 Scope of Study 3
1.5 Outline of Thesis 3
CHAPTER 2 -
2.LITERATURE REVIEW 4
2.1 Introduction 4
2.2 Building Codes & Standards 4
2.3 Optimum Cost of Reinforced Concrete Building 8
2.4 Factors Contributing To the Cost of Building Construction 9
2.5 Construction Cost 9
2.6 Research Methodology 10
2.7 Model OF Design 11
2.8 Design Specifications And properties of the structure 14
2.8.1 Materials and Design Parameters 14
2.9 Design Loading 15
2.9. Partial Safety Factors 16
2.9.3 Factors of Safety Loads And Strength Of Section By Strength 17
2.10 Design Methods 18
2.10.1 Object of Structural Design 18
2.10.2 Philosophy of Limit State Design 19
2.11 Project Flow Chart 21
2.11. Expected Results 22
CHAPTER 3 -
3. Design Of Slabs 23
3.1.1 Definition 23
3.1.2 Introduction 23
3.1.3 DesignConcepts 23
3.1.4 Types of slabs 24
3.1.5 One & two way slabs outlined 25
3.1.6 Econlomical Choice According to size and loading 26
3.1.7 Calculation of thickness for one way slab 27
3.1.8 Design procedure for one way slab 28
3.1.9 ACI Code specified method for two-way slabs 29
3.1.10 Two-way slab design procedure 29
3.1.11 Classification of slabs 29
3.1.12 Purpose of main steel in slabs 29
3.1.13 Analysis methods for slabs 30
3.1.14 Slabs direction in ribbed slab 30
3.1.15 Design concept 31

viii
3.1.16 Maximum Reinforcement Ratio 31
3.1.17 Shrinkage Reinforcement Ratio 31
3.1.18 Loads assigned to slabs 32
3.2.1 Elevation Plans of slabs 33
3.2.2 Design procedure for one-way slab 35
3.2.3 Design procedure for two-way slab 37
3.2.4 Data for Design 38
3.3 Design of two-way slab 39
3.5 Design of one -way slab 45
CHAPTER 4 -
4. Design of Beams 50
4.1 Introduction 50
4.2 Struvtural theory of beams 50
4.2.1 Types of a beam 50
4.2.2 Scope of usage of beam 51
4.2.3 Relation of reinforcement with section 51
4.3 Assumptions 54
4.4 Loading data 54
4.5 Design Procedure 55
4.6 Flow charts 56
4.7 Information about Sample of design 58
4.7. Desing assumptions 59
4.7.2 Check Deflection 59
4.7.3 Sizing the cross-section 59
4.8 Design of Flexure 60
4.8.1 Actual Depth 60
4.8.2 Minimum Ratio of steel required 60
4.8.3 Design Reinforcement for every moment in beam 60-68
4.9 Design of shear 69
4.10 Development length 75
CHAPTER 5 -
5. Design of Stairs 78
5.1 Geometrical design of stairs 78
5.1.2 Check for reliabilty 78
5.1.3 Check for angle 79
5.2 Detailed design of stair 81
5.3 No. of steps in each flight 82
5.4 Structural design of stairs 83
5.5 Design for flight no.1 & 3 86
5.6 Data for design for flight no 2 87
5.6.2 Design for flexure for flight no 2 88
5.7 Reinforcement details 71

ix
CHAPTER 6 -
6 . Design of Columns 90
6.1 Introduction 90
6.1.1 Types of reinforced concrete columns 90
6.1.2 Axial Load capacity of column 91
6.1.3 ACI code requirements for cast in place columns 92
6.1.4 General Configuration of moments with in columns 93
6.1.5 Classification of columns 94
6.1.6 Effective length 95
6.1.7 Design of axially loaded column 96
6.1.8 Types of reinforcements and their use 96
6.1.9 Safety provisions for columns 99
6.1.10 Design formula 101
6.2 Sample for Design 102
6.3 Design in detail 105
6.3.1 Design of moments 105
6.4 Buckling analysis for long column by moment magnification factor 109
6.6 Splices for columns 116
6.7 Usage of dowels 118
CHAPTER 7 -
7. Design of Foundations 120
7.1 Foundation design parameters 120
7.1.2 Allowable Settelment 121
7.2.1 General 122
7.2.2 Area of the footing 122
7.2.3 Depth of the footing 122
7.2.4 Depth from punching and shear consideration 122
7.3 General procedure of design of footing 122
7.4 Steps for structural Design 124
7.5 Data for design 125
7.6 Detailed Steps & formulas for design 127
7.7 Design of sample foundation 131
7.7.1 Area of footing 131
7.7.2 Footing Stability 132
7.7.3 Stregth of design 133
7.7.4 Check one way shear 133
7.7.5 Actual & allowable shear stress 133
7.7.6 Check two way shear 134
7.7.4 Check one way shear 133
7.8 Desing of flexure in long direction 136
7.9 Desing of flexure in short direction 137
7.10 Development length in footing 140

x
7.11 Bearing Stregth of column and footing 141
7.12 Development length in dowels 142
CHAPTER 8 -
8. CONCLUSION AND FUTURE WORK 143
8.1 Conclusion 143
6.2 Suggestion of Further Works 144
REFERENCES

xi
LIST OF TABLES
Table 2.1: Design input detail of building 13
Table 2.2: Initial Sizes and Specification of building 14
Table 2.3: Areas of groups of bars 15
Table 2.4:Detail Dead load 15
Table 2.5: Detail of Self weight of slab 16
Table 2.6: partial Safety factors according to ACI 318-02 17
Table 2.7: Live Loads from ASCE 17
Table 3.1 : Minimum thickness of beam & slabs 27
Table 3.2: Reinforcement of one-way slab 49
Table 4.1: Design for Shear by stirrups under ACI 318-08 69
Table 4.2: Beam Reinforcement tables 77
Table 5.1: Data for design of stairs 79
Table 6.1 : Preliminary assumed sections of columns 104
Table 6.2: Design Value Obtained from Robot -Analysis 105
Table 6.3: Columns Reinforcements -
Table 7.1: Servicbilty load for foundations 131
Table 7.2: Reinforcement table for foundations 142

xv
LIST OF FIGURES & FLOW –CHARTS
Figure 1.1: Front view of building 3
Figure 1.2: Side view –A of Buiding 4
Figure 1.3: Side view –B 5
Figure 1.4: perespective view 5
Figure 2.1:Design /Cost Relation Ship 10
Figure 2.2: Model of R.A for design 11
Figure 3.2 : Axis –Plan 11
Figure 2.4: First and Second floor plan 12
Figure 2.5: Ground Floor plan 13
Flow-chart1 : Desing Procedure 21
Figure 3.1 : Typical types of slabs 25
Figure 3.1.1:Elevation plans for ground floor showing assigned slab names 33
Figure 3.1.2:Elevation plans for first floor showing assigned slab names 33
Figure 3.1.3 :Elevation plans for Second floor showing assigned slab names 34
Figure 3.3: Slab S2 , two way slab as design sample 39
Figure 3.4: One way slab S8 for design 45
Figure 4.1: Types of beams 50
Flow-chart4.1 : Design procedure for singly reinforced rectangular section 56
Flow-chart4.2 : Design procedure for Doubly reinforced rectangular section 57
Figure 4.2: B.M.D for beam 59 from robot structural analysis 58
Figure 4.3: Spans and sections of beam 59 for design 59
Flow-chart4.3 : Design procedure for Shear of beams 70
Figure 4.4: S.F.D for beam 59 from robot structural analysis 71
Figure 4.5 : Reinforced concrete beams reinforcement model 77
Figure 5.1 : Dimensions of stairs 78
Figure 5.3 :plan for stairs 80
Figure 5.4 :vertical cut section of stairs 80
Figure 5.5 :Loading diagram for flight 1 & 3 83
Figure 5.6 :B.M.D for flight 1 & 3 83
Figure 5.8-5.10 :Loading -B.M.D and S.F.D or flight 2 86
Figure 5.7: Reinforcment for stairs 88

xv
Figure 6.1: Shows interior and exterior columns 94
Figure 6.3: Different kinds of column reinforcements 99
Figure 6.4: Elevation plans showing assigned names to coloumns of different
stories of the building 88
Figure 6.7: Shows governing case of column 59 with axial load and moments 99
Figure 6.8: shows section of column 59 115
Figure 6.9: shows minimum requirements for splices 116
Figure 6.10: Reinforcment detail of columns 118
Figure 6.11: Naming of columns from R.S.A 118
Figure 7.2: Foundation plans showing assined names to foundations 125
Figure 7.3: Shows load on foundation by 3d structural model on R.S.A 126
Figure 7.4: Showing dead and live load on foundation 33 under column 59 126
Figure 7.5: Typical reinforcment of foundation 139

xiv
LIST OF APPENDICES
APPENDIX TITLE PAGE
A Charts 145

Design of Reinforced Concrete Multi-story Commercial building
‫ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬‫ــ‬‫ـــــــــــــــــــــــــــ‬‫ــــــــ‬‫ـــــــــــــــــــــــــــ‬‫ــــــــــــ‬
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INTRODUCTION To Design & Analysis of Reinforced Concrete Multi-story
Building Under ACI Code .
1.1 Research Background
Structural design is a process of selecting the material type and conducting in-depth calculation of
a structure to fulfill its construction requirements. The main purpose of structural design is to
produce a safe, economic and functional building. Structural design should also be an integration
of art and science. It is a process of converting an architectural perspective into a practical and
reasonable entity at construction site. (Chan Chee, 2007)
One of the important things to be considered in any construction is the cost effectiveness
(i.e. how economical the construction will be at the end of construction). Often a times,
constructions become uneconomical (too expensive) when too much emphasis is laid on the quality
alone. Therefore there should be a balance between quality control and cost effectiveness.
The codes and standards that impact modern building construction are constantly in flux and
changing, and it is difficult to keep up with copious changes and how they will impact building
design. In the structural design of concrete structures, Refereeing to standard code is essential. A
standard code serves as a reference document with important guidance. The contents of the
standard code generally cover comprehensive details of a design. These details include the basis
and concept of design, specification to be followed, design methods, safety factors, loading values
and etc. These codes and standards define the parameters in the reinforced concrete design process
that affect the cost of materials. This would include the dimensions(X, Y, Z) of the different
reinforced concrete elements, the area of reinforcements and ratio of reinforcement limit values.
1.2 Problem statement.
Accurately Analyzed structures are important during the design phase to minimize the construction
cost. Excellent designers must have the ability to organize and manage the process of design so
with special consideration to cost effectiveness during the design process.

2
In today’s construction industry, the commonest codes of practice used are the ACI and BS
codes. However the problem of cost ineffectiveness is becoming so rampant. Although lack of
experience from the engineers also affects the design which eventually affect the cost. For this
reason this research is dedicated to find out the process of assembling different building
components under strictly followed recommendations of one of the aforementioned code i.e ACI-
318-08.
1.3 Objectives.
The main objectives of this study are:
1- To make analysis by ACI code in order to obtain the most safe and sound solution.
2- To ascertain the accuracy of the analysis and the design using software (Robot Analysis)
3- To achieve an ultimate design in terms of quality at minimal cost.
1.4 Scope of study.
The project focuses mainly design of concrete and reinforcement, the structure is a three storey
building. This structure is intended to serve as a commercial building. The main reason why a
three-storey structure is being adopted is that it does not involve calculation for the wind load, The
code used is ACI 318-08 And the selected software to used is Robot Analysis.

3
1.5 Architectural model of Building : ALL of the Architectural work is done by author,

4

5
+
Fig 1.3 Right Side view
Fig1.4 perspective view

6
1.6 Outline of Thesis
The thesis is organized into five chapters. Each chapter begins with a brief introduction of what
to be encountered.
Chapter 1 is a brief overview of the research background and the objectives of the study
followed by the outline of thesis.
Chapter 2, which discusses the research methodology that was adopted for the research.
The chapter deals with the definition of model for designing multi stories reinforced concrete
multi-purpose building, which had built and consists of three floors. The properties of design
model are shown in the first part of its chapter such as the dimensions, the properties of materials
(concrete, steel), the unit weight of concrete and blocks, and the values of loads (dead load and
live load) which depends on the type of building.
Chapter 3 presents the general literature about slabs and proceeds with results of analysis
of slabs by designing a sample element.
Chapter 4 presents the general literature about beams and proceeds with results of analysis
of beams by designing a sample.
Chapter 5 presents the general literature about Stairs and proceeds with results of analysis
of stairs by designing in detail.
Chapter 6 presents the general literature about Columns and proceeds with results of
analysis of Columns by designing a sample element.
Chapter 7 presents the general literature about Foundations and proceeds with results of
analysis of foundations by designing a sample.
Chapter 8 summarizes the project results that have been carried out. The finding of the
study is described. A future recommendation to extend the study is also proposed.

7
2. LITERATURE REVIEW.
2.1 Introduction:
The term “Design of reinforced concrete building” consists of two main elements, which
includes the concrete design and the design of reinforcement.
2.2.1 BUILDING CODES AND STANDARDS.
The codes and standards that impact modern building construction are constantly in flux, and it is
difficult at best to keep up with copious changes and how they will impact building design. For
engineers and architects who is working with structural design.
2.2.2 BS 8110 BUILDING CODE: PART 1:1997.
BS 8110 part 1 gives recommendations for the structural use of concrete building and structures,
excluding bridges and structural concrete made with high alumina cement. The aim of design is
the achievements of an acceptable probability that structures being design will perform satisfactory
during their intended life. With an appropriate degree of safety, they should sustain all the loads
and deformation of normal construction and use and have adequate durability and resistance to the
effects of misuse and fire. The structure should be so designed that adequate means exist to
transmit the design ultimate dead, wind and imposed loads safely from the highest supported level
to the foundations (British code, 1997).
The design strengths of materials and design loads should be based on the loads and material
properties as in the BS 8110 and as appropriate for the serviceability limit state (SLS). The design
should satisfy the requirement that no SLS is reached by rupture of any section, by overturning or
by buckling under the worst combination of ultimate loads.

8
2.2.3 ACI 318 BUILDING CODE (ACI 318-02).
The American concrete institute standard 318, building code requirements for reinforced concrete,
has permitted the design of reinforced concrete structure in accordance with limit state principles
using load and resistance factors since1963. A probabilistic assessment of these factors and
implied safety levels is made, along with consideration of alternate factors values and formats. (A
discussion of issues related to construction safety of existing structure is included). Working stress
principles and linear elastic theory formed the basis for reinforced concrete design prior to 1983,
when the concept of ultimate strength design was incorporated in the ACI building code (ACI318-
02), (Edward cohen, 1971). Because of the highly nonlinear nature of reinforced concrete behavior,
the linear approach was unable to provide a realistic assessment of true safety levels (Andrew
Scanlon, 1992).
The developers of ACI 318-02, who introduced the idea of load and resistance factors to
account for uncertainties in both load and resistance .Probabilistic methods were developed and
refined during the late 1960s in response to the need to consider variability and uncertainty,
explicitly and rationally. Proposed formulations include code incorporation of explicit second
moment probabilistic procedures. In such an approach, the designer would select a desired safety
index “B” and carry out the design utilizing the means standard deviations of the load and
resistance variables. The safety index positions the mean load effect to ensure attainment of the
target reliability (American code). The explicit second moment approach was not considered by
ACI38 or other major code writing organizations. (Edward Cohen, 1971).
2.3 OPTIMUM COST OF REINFORCED CONCRETE BUILDING.
The meaning of the optimum cost of reinforced concrete building with some studies, which it is
minimum quantity of concrete and steel in any construction or it is the minimum cost of the
construction but the most studies explains the optimum cost by minimum quantity of concrete and
steel in any construction.
Hence, the primary objective of economic analysis is to secure cost-effectiveness for the
client. In order to achieve this, it is necessary to identify and to evaluate the probable economic

9
outcome of a proposed construction project. An analysis is required from the viewpoint of the
owner of the project when doing the proposal, the analysis can be evaluated the followings
(Ashworth A., 1994) to achieve maximum profitability from the project concerned, to minimize
construction costs within the criteria set for design, quality and space, to maximize any social
benefits, to minimize risk and uncertainty and to maximize safety, quality and public image.
Cost and safety are one of the important factors that will affect method of construction,
quality of work, period of the construction and most of all, the success of a project. It seeks to
ensure the efficient use of all available sources to construction. Client’s requirements, possible
effect on the surrounding areas, relationship of space and shape, assessment of the initial cost, the
reason for, and method of, controlling costs, the estimation of the life of buildings and material
need to be studied so as to improve the efficiency of control in construction (Flanagan R. and Tate
B., 1997).
2.4 FACTORS CONTRIBUTING TO THE DESIGN OF BUILDING CONSTRUCTION.
Implementation of a construction projects is a complicated and complex process (Neap H.S and
Celik T., 2001). Phases of construction are divided into categories such as material, labor, plant,
supervision, All disturbances regarding the cost must be detected periodically (Popescu, 1977).
The collection, analysis, publication and retrieval of designed information are very important to
the construction industry. Contractors and surveyors will tend, wherever possible, to use their own
generated data in preference to commercially published data, since the former incorporate those
factors which are relevant to them. Published data will therefore be used for backup purpose. The
existence of a wide variety of published data leads one to suppose, that it is much more greatly
relied on than is sometimes admitted (Ashworth A., 1994)
2.5 BASIC PRINCIPLES OF COST
Most decision makers recognize that there are only a few variables that have a large influence on
a building’s costs. Brandon has classified these variables into two categories decisions

10
concerning the size of the buildings and decisions concerning material specifications and building
configuration (Figure 2.1).
Figure 2.1 Design / Costs relationships
2.6 RESEARCH METHODOLOGY.
The proposed methodology is based on designing the building by software program (Robot
Structural Analysis) with ACI Code, each code has different properties of concrete and steel ,such
as the concrete compressive strength (fc), the yield strength of steel (fy) ,the various combinations
of the load, the allowable ratio for minimum and maximum reinforcement and other properties ,
in practice ,design of the elements are governed by various architectural requirements. If the height
and width of the beam are located ,the designs allocates the right amount of steel but, in this
study ,we assumed that the dimension of the beams and columns are not given .hence ,during the
design by R.S.A software, we will start with small dimensions ,in this case the program will check
if the dimensions were acceptable or not ,here if the dimensions are small the message from
program report will come out “please note: max/min reinforcement sizes do not permit acceptable
bar spacing ,increase member size” .so, we will increase the member size till we get the first
acceptable dimensions that have the first acceptable amount of steel.
Specificatio
n and shape
Area
Cost

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2.7 MODEL OF DESIGN.
The model that will be designed is a multi-stories reinforced concrete commercial building which
has length of 20.00 m x 21 m width and the building consists of three stories, two stories upon the
ground with height 4m. Figure 2.1, 2.2, 2.3, 2.4 shows the plan of the building.
Figure 2.2
Figure 2.3 Axis Plan.

Prayer
Room
6.00m
3.50m
4.40m
7.00m
7.00m
6.00m
6.20m
19.60m
21.20m
7.00m
7.00m
4.20m
1.40m
2.30m
3.50m
0.30m
6.20m
3.50m
1.5
3.60m
2.40m
2.40m
CLEANERS ROOM
Shop Shop
Shop
Toilet
WOMENSTOILET
MENSTOILET
‫ﺔ‬ ‫اﻟﮭﻧدﺳ‬ ‫ﺔ‬ ‫ﻛﻠﯾ‬
‫ﻧﻰ‬‫ﻟﻠﻣﺑ‬‫ﻲ‬‫اﻻرﺿ‬‫دور‬‫ﻟ‬‫ﻲ‬‫اﻻﻓﻘ‬‫ﻘط‬‫اﻟﻣﺳ‬
‫د‬ ‫وﻟﯾ‬ ‫ﻧﻲ‬ ‫ﺑ‬ ‫ﺟﺎﻣﻌﺔ‬
Area=405.5m²
‫ك‬‫ﺑﯾ‬‫م‬‫ﻧﻌﯾ‬‫م‬‫اﻟﻌظﯾ‬‫د‬‫ﻋﺑ‬
‫اﻋداد‬
‫م‬‫اﻟرﺳ‬
2016™
‫د‬‫وﻟﯾ‬‫ﻧﻲ‬‫ﺑ‬‫ﺟﺎﻣﻌﺔ‬‫ﺔ‬‫اﻟﮭﻧدﺳ‬‫ﺔ‬‫ﻛﻠﯾ‬Date:2/8/2016
3.00m
1.00m
1.20m
1.70m
‫ﺎري‬‫ﺗﺟ‬‫ﻧﻲ‬‫ﻣﺑ‬‫ﻣﯾم‬‫ﺗﺻ‬‫روع‬‫ﻣﺷ‬
ArchitecturalLayoutofElevationplan
1.40
Shop

‫ﺔ‬ ‫اﻟﮭﻧدﺳ‬ ‫ﺔ‬ ‫ﻛﻠﯾ‬
‫ﻧﻰ‬‫ﻟﻠﻣﺑ‬‫ﺎﻧﻲ‬‫اﻟﺛ‬‫و‬‫اﻻول‬‫دور‬‫ﻟ‬‫ﻲ‬‫اﻻﻓﻘ‬‫ﻘط‬‫اﻟﻣﺳ‬
‫د‬ ‫وﻟﯾ‬ ‫ﻧﻲ‬ ‫ﺑ‬ ‫ﺟﺎﻣﻌﺔ‬
‫ك‬‫ﺑﯾ‬‫م‬‫ﻧﻌﯾ‬‫م‬‫اﻟﻌظﯾ‬‫د‬‫م.ﻋﺑ‬‫اﻋداد‬
‫م‬‫اﻟرﺳ‬
2016™:
Area=405.5m²
Prayer
Room
6.00m
3.50m
4.40m
7.00m
7.00m
6.00m
6.20m
19.60m
21.20m
7.00m
7.00m
2.30m
3.50m
0.30m
6.20m
3.50m
1.5
3.60m
2.40m
2.40m
CLEANERS ROOM
Shop Shop
Shop
Toilet
WOMENSTOILET
MENSTOILET
3.00m
1.00m
1.20m
1.70m
Shop
6.20m
4.20m
1.40m
1.5
Shop
‫د‬‫وﻟﯾ‬‫ﻧﻲ‬‫ﺑ‬‫ﺟﺎﻣﻌﺔ‬‫ﺔ‬‫اﻟﮭﻧدﺳ‬‫ﺔ‬‫ﻛﻠﯾ‬
‫ﺎري‬‫ﺗﺟ‬‫ﻧﻲ‬‫ﻣﺑ‬‫ﻣﯾم‬‫ﺗﺻ‬‫روع‬‫ﻣﺷ‬
ArchitecturalLayoutofElevationplan
2.30
2.80m

14
Table 2.1 Design input detail of the building
2.8 DESIGN SPECIFICATIONS AND PROPERTIES OF THE STRUCTURE
The initial sizing of members and specifications of the frame building are shown in Table 3.2. The
initial sizes of member were checked against the conditions according to serviceability limit state
and ultimate limit state. The sizes were adjusted until the conditions of serviceability limit state
and ultimate limit state stated in ACI318-08 were satisfied.
Structural Elements Dimensions(exterior) Dimensions(Interior)
Columns Ground floor 500x250 mm 600x250 mm
1th
to 2th
400x250 mm 500x250 mm
Beams Tie Beam(plinth) 250x600 mm 250x600 mm
1th
to 2th
250x400 mm 250x500 mm
Slab 200 mm THK.
No. of stories 3 stories
Beam to column connection = fixed
Column to base connection = fixed
Table 2.2 Initial sizes and specification of the building according to ACI318 code
2.8.2 MATERIAL PROPERTIES.
Every material has different properties that are simply of their own. Similarly, the material used in
the design of the structure in this research also has different properties and strength. Table 3.4, 3.5
lists the material properties applied in the preliminary analysis of the design of the structural
Building usage Shops
Story height Ground floor 4 m
1th
& 2th
4 m
Length of building 21.00 m
Width of building 20.00 m
Height of building 13.8 m

15
members (beams, slabs and columns, etc.) The values of compressive strength of concrete, yield
stress of reinforcement, concrete density and modulus of elasticity conforms to ACI 318.
Structure Elements Parameters
Compressive strength; fcu. Beams, Slabs, Columns 25N/mm
Density of concrete 24 kN/m
Modulus of elasticity; E 21.718 KN/mm
Yield stress fy 420 N/mm
Table 2.3 Material Properties conform to ACI318 code
2.9 PROCEDURES OF DETERMINATION OF LOADING.
The simulation of load determination on members of the structure on three dimensional structural
frames was used; the procedure utilizes load analysis to find the dimension of members to be used
later on finding the optimal design. Dead load and live load were applied to the structure.
2.9.1 Determination Dead Load.
All of the dead loads are according to the (ACI318) Code. It is defined as the sum of all constant
and continuous loads occurred on the building
Which represents:
 Own weight of structure
 Floor covering
 Wall loads
 Flooring cover
Flooring cover represents the weight of finishing materials on floor, such as sand, bitumen, mortar
and marble. Table 3.8 shows the details of dead load on floor and surface slabs.
DEAD LOAD (FLOORING COVERING )
FROM TYPE MAGNITUDE UNIT
floor slab Area pressure 1.00 KN/m2
Surface slab( Roof) Area pressure 2 KN/m2
Table 2.4 Details of dead load on surfaces as component of concrete slab

16
 Own weight of structure
Own weight of structure represents the weight of the main elements of the building,
such as slabs, beams and columns. Table 3.3 shows the details of slabs weight according to
ACI318-08 codes.
DEAD LOAD
FROM TYPE MAGNITUDE UNIT
Slab self weight of
200 mm thickness
(without finishes)
Area pressure 4.2 KN/m2
Table 2.5 Details of slab self-weight according to ACI318 Code
 Wall loads:
The wall in the building is from concrete blocks, the thickness of wall is 0.25m for
exterior wall and 0.2m for interior wall, therefore, the load of wall on beam will be:
 For exterior walls:
H = 4m
W= 0.25 X 4 X18 + 0.02 X 4 X 24 =19.92 KN/m
 For interior walls:
H = 4m
W= 0.2 X 4 X18+ 0.02 X 4 X 24 = 16.32 KN/m
2.9.2 Partial Safety Factors According To ACI 318-02 CODE
The strength reduction factors ,φ,are applied to specified strength to obtain the design strength
provided by a member .the φ factors for flexure ,shear ,and torsion are as shown in Table 2.6.

17
Φ=0.9 for flexure (tension controlled)
Φ=0.75 For shear and torsion.
Φ=0.65 For axial compression (columns)
Table2.6: Partial safety factor according to ACI318-02
2.9.2.2 Determination Live Load
It is defined as the sum of all variable movable loads occurring in the building.
This represents:
 Human weights
 Furniture weights
Type of building (office building) LOAD
(KN/m2
)
Catwalks for maintenance access 1.92
Access floor system
Office use 2.4
Computer use 4.79
File and computer rooms shall be designed for heavier loads based on
anticipated occupancy
Lobbies and first-floor corridors
4.79
Offices 2.40
corridors above first floor 3.83
Balconies (exterior) 4.79
Catwalks for maintenance access 1.92
Private rooms and corridors serving them 1.92
Public rooms and corridors serving them 4.79
Table 2.7 American standard Design Minimum Loads for Building.
Note: Refer to ASCE 7-05 Section 4.9 (pg 12), Table 4.1

18
2.9.3 Design load combinations:-
 Load factors according to ACI Code.
The design load combinations are the various combination of the load cases for which the structure
needs to be designed. For ACI 318-08 if a structure is subjected to dead load (D), live load (L), the
required strength U to resist dead load D and live load L shall not be less than Combination factors
(LRFD):
 U = 1.4D
 U = 1.2D + 1.6L
Where:
o D = dead load;
o L = live lopad.
2.10 Design Methods
There are two acceptable methods to design concrete: the working stress method and the
ultimate strength method (Wight & jamesr, 2005) (Mehdi & Robert, 2007). The ultimate
stress method is the one most commonly used. The reasons for this are the ultimate strength
method will require substantially less concrete and rebar, and the design calculations are
easier. Working stress design model assumes that as the concrete beam bends due to induced
moments the strain relationship between the rebar in tension and the concrete in compression
remain constant. Ultimate strength design places the rebar in full yield so the strain
relationship between reinforcement and concrete is ignored and a rectangular concrete
compression block stressed at design strength is formed.
2.10.1 Object of Structural Design
The permissible stress and ultimate strength methods have served their purpose over the
years. However, the engineers have always realized the shortcutting of these methods and
been on the outlook for improvements in the process of design.
The purpose of design may be stated the provision of a safe and economical structure
complying with the clients’ requirements (Rowe et al., 1995). In other words, the process

19
of design should ensure a balance between total cost of the structure and an acceptable
probability of the structure becoming unserviceable during its life. Limit state design is
based on this philosophy. It recognizes the need to provide a safe and efficient structure at
an economical price. Simultaneously, it gives clear idea of actual factors of safety used to
take into account elements of uncertainty and ignorance.
2.10.2 Philosophy of Limit State Design
Limit state design takes account of the variations and uncertainties that may occur in
the design and construction of structures. Different safety factors are provided for those
variations in design and construction. Safety and serviceability are expressed in terms of
the probability that the structure will not beware unfit for its intended pur-pose during its
life. Limit state for use may arise in various ways, the principal ones being as (Mehdi &
Robert, 2007) (Wight & jamesr, 2005):
(1) Ultimate limit states: the usual collapse limit. States including collapse due to fire,
explosive pressure etc.
(2) Serviceability limit state: focal damage and deflection limit states, durability, vibration,
ere penetration and heat trans-mission etc.
Limits states of collapse may be defined as occurring when a part or the whole of the
structure fails under extreme loads. It may be due to rupture of one or more critical sections, loss
of overall stability or buck-ling owing to elastic or plastic instability.
Limit states due to local damage may occur, when cracking or spalling of concrete impairs the
appearance or usefulness of the structure or adversely affects finishes, partitions etc. For example,
a check on the limit state of crack width may be necessary in water retaining structures or structures
situated in severe environments. Similarly, it may be necessary to check the limit state of crack
formation in compression to ensure that no initial microcracking, which could be harmful to the
durability of the member, is produced at any stage of construction in zones subject to high
compressive stresses.
Limit states of deflection or deformation may be defined as occurring when it becomes
excessive to impair the appearuruce or usefulness of the structure and may cause discomfort to
users. In certain cases limit states of other effects such as vibration, fatigue, impact, durability of

20
fire damage may also have to be considered: For example, the limit states design of bridges
requires the investigation of limit states of vibration and fatigue in addition to collapse, cracking
and deflection (Mehdi & Robert, 2007). Similarly, the consideration of limit states of impact
resistance is essential for structures, which may be subjected to impact, explosions or earthquakes.
The usual approach is to design the structure because of limit states for collapse and then check
that the criteria governing remaining limit states are satisfied. The limit state of collapse under
extreme loads is investigated by ultimate strength theory of reinforced concrete, while the limit
states of deflection and local damage both utilize the elastic theory (Mehdi & Robert, 2007).

21
2.11 Project flow chart.
Error
Flow chart 1 : Design procedures
START
Generate Plan in AutoCAD Software
Assigning Of Elements Based On assumed Structure
Plan
General a 3D Model
Correct any errors, Recheck Properties of Elements
Assign Loads and Load Cases Acting On the Structure
Decrease Spacing
between members or
add new members(such
as column )
Run Analysis
Run R.C member
Required Reinforcement
Calculations
Run Provided
Reinforcement wizard &
Check The Steel Ratio ρ.
Change the dimensions of
section
Ρmax< ρ< ρmin
Ρmax< ρ< ρmin
Report Design Results
Import the 2d plan to 3d
software to process
architectural
visualization and
establish ensuring it
compliance with
structural midel
Import Structure Plan
into (Autodesk Robot
Structure Analysis)
Architectural output
Drawings

22
2.10.1 EXPECTED RESULT.
1- The most economical alternative solution would be identified.
2- The required quantity of material would be evaluated.

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Design Of Slabs
3. Design of Slabs
3.1.1 Definition: - A slab is structural element whose thickness is small compared
to its own length and width. Slabs are usually used in floor and roof
construction. According to the way loads are transferred to supporting
beams and columns, slabs are classified into two types; one-way and two-
way
3.1.2 Introduction
The slab provides a horizontal surface and is usually supported by
columns, beams or walls. One-way slab is the most basic and common type of
slab. One-way slabs are supported by two opposite sides and bending occurs in
one direction only. Two-way slabs are supported on four sides and bending
occurs in two directions. One-way slabs are designed as rectangular beams
placed side by side.
3.1.3 DESIGN CONCEPTS:
An exact analysis of forces and displacements in a two-way slab is complex, due
to its highly indeterminate nature; this is true even when the effects of creep and
nonlinear behavior of the concrete are neglected. Numerical methods such as
finite elements can be used, but simplified methods such as those presented by
the ACI Code are more suitable for practical design. The ACI Code, Chapter 8,
assumes that the slabs behave as wide, shallow beams that form, with the
columns above and below them, a rigid frame. The validity of this assumption of
dividing the structure into equivalent frames has been verified by analytical and
experimental research. It is also established that factored load capacity of two-
way slabs with restrained boundaries is about twice that calculated by theoretical
analysis because a great deal of moment redistribution occurs in the slab before
failure. At high loads, large deformations and deflections are expected; thus, a
minimum slab thickness is required to maintain adequate deflection and cracking
conditions under service loads.
However, slabs supported by four sides may be assumed as two-way
slab when the ratio of lengths to width of two perpendicular sides exceeds 2.
Although, while such slabs transfer their loading in four directions, nearly all
load is transferred in the short direction. Two-way slabs carry the load to two
directions, and the bending moment in each direction is less than the bending
moment of one-way slabs. Also two-way slabs have less deflection than one-way
slabs.

Design Of Slabs
Compared to one-way slabs, Calculation of two-way slabs is more complex. Methods for
two-way slab design include Direct Design Method (DDM), Equivalent frame method
(EFM), Finite element approach, and Yield line theory. However, the ACI Code specifies two
simplified methods, DDM and EFM.
Slabs maybe solid of uniform thickness or ribbed with ribs running in one or two
directions. Slabs with varying depth are generally not used. Slab are horizontal
plate elements forming floor and roof in building and normally carry lateral
actions.
3.1.4 Types of Slabs
 Ribbed slabs: Slab cast integrally with a series of closely spaced
joist which in turn are supported by a set of beams. Designed as a
series of parallel T-beams and economical for medium spans with
light to medium live loads.
 Waffle slabs: A two-way slab reinforced by ribs in two-dimensions.
Able to carry heavier loads and span longer than ribbed slabs.
 Flat slabs: Slabs of uniform thickness bending and reinforced in two
directions and supported directly by columns without beams.
 Flat slabs with drop panel: Flat slab thickness at its column
supports with column capitals or drop panels to increase strength and
moment-resisting capacity. Suitable for heavily loaded span
3.1.5 One & two way slabs outlined:
 One-way slabs
1. One-way Beam and slab / One-way flat slab:
These slabs are supported on two opposite sides and all bending moment
And deflections are resisted in the short direction. A slab supported on
Two sides with length to width ratio greater than two, should be designed
As one-way slab.
2. One-way joist floor system:
This type of slab, also called ribbed slab, is supported by reinforced
Concrete ribs or joists. The ribs are usually tapered and uniformly spaced
And supported on girders that rest on columns.
 Two-way slab
1. Two-way beam and slab: If the slab is supported by beams on all four
sides, the loads are transferred to all four beams, assuming rebar in both
directions.
2. Two-way flat slab: A flat slab usually does not have beams or girders but is
supported by Drop panels or column capitals directly. All loads are

Design Of Slabs
transferred to the Supporting column, with punching shear resisted by drop
panels.
3. Two-way waffle slab: This type of slab consists of a floor slab with a
length-to-width ratio less Than 2, supported by waffles in two directions.
Fig. 3-1: Typical type of slabs (ACI,1994)

Design Of Slabs
3.1.6 ECONOMICAL CHOICE OF CONCRETE FLOOR SYSTEMS
ACCORDING TO SIZE, DIMENSIONS AND LOADINGS REQUIRED:
Various types of floor systems can be used for general buildings, such as
residential, office, and in institutional buildings. The choice of an adequate and
economic floor system depends on the type of building, architectural layout,
aesthetic features, and the span length between columns. In general, the
superimposed live load on buildings varies between 5 and 10 KN/m. A general
guide for the economical use of floor systems can be summarized as follows:
1. Flat plates: Flat plates are most suitable for spans of 6m to 7.5m and live
loads between 4 and 6.5 KN/m. The advantages of adopting flat plates include
low-cost formwork, exposed flat ceilings, and fast construction. Flat plates have
low shear capacity and relatively low stiffness, which may cause noticeable
deflection. Flat plates are widely used in buildings either as reinforced or
prestressed concrete slabs.
2. Flat slabs: Flat slabs are most suitable for spans of 6mto 9m and for live loads
of 5.5 to 10 KN/m they need more formwork than flat plates, especially for
column capitals. In most cases, only drop panels without column capitals are used.
3. Waffle slabs: Waffle slabs are suitable for spans of 9m to 14.5m and live loads
of 5.5 to 10 KN/they carry, heavier loads than flat plates and have attractive
exposed ceilings. Formwork, including the use of pans, is quite expensive.
4. Slabs on beams: Slabs on beams are suitable for spans between 6m and 9m and
live loads of 4 to 8 KN/m. The beams increase the stiffness of the slabs, producing
relatively low deflection. Additional formwork for the beams is needed.
5. One-way slabs on beams: One-way slabs on beams are most suitable for spans
of 0.9 to 1.8m and a live load of 4 to 7KN/m. They can be used for larger spans
with relatively higher cost and higher slab deflection. Additional formwork for the
beams is needed.
6. One-way joist floor system: A one-way joist floor system is most suitable for
spans of 6 to 9 m and live loads of 5.5 to 8.2 KN/m, Because of the deep ribs, the
concrete and steel quantities are relatively low, but expensive formwork is
expected. The exposed ceiling of the slabs may look attractive.

Design Of Slabs
3.1.7 Calculation of thickness for one way slab:
Table 3.1 Minimum thickness of beams
Table 3.2 Minimum thickness of beams for exterior panels

Design Of Slabs
3.1.8 Design Procedure:
 One-way slab design
1. Decide the type of slab according to aspect ratio of long and short side
Lengths.
2. Compute the minimum thickness based on ACI Code.
3. Compute the slab self-weight and total design load.
4. Compute factored loads (1.4 DL + 1.7 LL).
5. Compute the design moment.
6. Assume the effective slab depth.
7. Check the shear.
8. Find or compute the required steel ratio.
9. Compute the required steel area.
10. Design the reinforcement (main and temperature steel).
11. Check the deflection.
3.1.9 The ACI Code specifies two methods for the design of two-way slabs:
1. The direct design method, DDM (ACI Code, Section 8.10), is an
approximate procedure for the analysis and design of two-way slabs. It is
limited to slab systems subjected to uniformly distributed loads and
supported on equally or nearly equally spaced columns. The method uses a
set of coefficients to determine the design moments at critical sections.
Two-way slab systems that do not meet the limitations of the ACI Code,
Section 8.10.1.1, must be analyzed by more accurate procedures.
2. The equivalent frame method, EFM (ACI Code, Section 8.11), is one in
which three-dimensional building is divided into a series of two
dimensional equivalent frames by cutting the building along lines midway
between columns. The resulting frames are considered separately in the
longitudinal and transverse directions of the building and treated floor by
floor.

Design Of Slabs
3.1.10 Two-way slab design procedure by the Direct Design Method
1. Decide the type of slab according to aspect ratio of long and short side
Lengths.
2. Check the limitation to use the DDM in ACI Code. If limitations are not
met, the DDM cannot be used.
3. Determine and assume the thickness of slab to control deflection.
4. Compute the slab self-weight and total design load.
5. Compute factored loads (1.4 DL + 1.7 LL).
6. Check the slab thickness against one-way shear and two-way shear.
7. Compute the design moment.
8. Determine the distribution factor for the positive and negative moments
using ACI Code.
9. Determine the steel reinforcement of the column and middle strips.
3.1.11Classification of slabs:
Slabs are plate elements forming floors and roofs in buildings which normally
carry uniformly distributed loads.
Slabs may be simply supported or continuous over one or more supports and
are classified according to the method of support as follows:
 One-end continuous
 Both-End continuous
3.1.12 Purpose of main and secondary steel: The distribution steel should be tied
above the main steel, otherwise the lever arm which is measure up to the
center of the main steel shall be reduced resulting in the reduction of the
moment of the resistance
 Purpose of Main steel:
 It takes up all the tensile stresses developed in the structure
 It increase the strength of concrete sections
 Purpose of distribution steel:
 It distribute the concentrated load on the slab
 It guards against shrinkage and temperature stress
 It also keeps the main reinforcement in the position

Design Of Slabs
3.1.13 Types of analysis-methods for slabs:
 Elastic analysis covers three techniques:
(a) Idealization in to strips or beams spanning one way or a grid with the
strips spanning two ways
(b) Elastic plate analysis
(c) Finite element analysis: (Used By the software Robot analysis in
this project)
The best method for irregularly shaped slabs or slabs with non-uniform
loads
 Method of design coefficients use is made of the moment and shear
coefficients given in the code, which have been obtained from yield line
analysis.
 The yield line and Hillerborg strip methods are limit design or collapse
loads methods
3.1.14 Slabs direction In Ribbed Slab
Direction of one way slab: In one-way ribbed slabs ribs may be arranged in
any of the two principal directions. Two options are possible; the first is by
providing ribs in the shorter direction as shown in Figure a, which leads to
smaller amounts of reinforcement in the ribs, while large amounts of
reinforcement are required in the supporting beams, associated with large
deflections.
`

Design Of Slabs
The second option is by providing ribs in the longer direction as shown in
Figure b, which leads to larger amount of reinforcement in the ribs, while
smaller amounts of reinforcement are required in the supporting beams
associated with smaller deflections compared to the first option. The
designer has to make up his mind regarding the option he prefers. Some
designers opt to run the ribs in a direction that leads to smaller moments
and shears in the supporting beams which means much more reinforcement
in the ribs. Other designers opt to run the ribs in the shorter direction which
leads to much more reinforcement in the supporting beams. The later option
leads to more economical design.
3.1.15 Design Concept:
One-way solid slabs are designed as a number of independent 1 m wide strips
which span in the short direction and supported on crossing beams.
 Practical rules:
 THE overall thickness of a slab shall not be less than 7.5 cm, the top
surface of centering shall be given a camber of 7mm per meter span
subject to maximum of 4.5 cm.
 Reinforcements: the minimum reinforcement in slabs in either
direction shall be not less than 0.15 percent of the gross sectional area
of the concrete and which may be 0.12 percent where high yield
strength deformed bars .
3.1.16 Maximum Reinforcement Ratio:
One-way solid slabs are designed as rectangular sections subjected to shear and
moment. Thus, the maximum reinforcement ratio corresponds to a net stain in the
reinforcement, e of 0.004.
3.2.17 Shrinkage Reinforcement Ratio
According to ACI Code 7.12.2.1 and for steels yielding at f 4200 kg / cm2 y = ,the
Shrinkage reinforcement is taken not less than 0.0018 of the gross concrete area,
or
A=  b h ;  shrinkage = 0.0018.
Where, b = width of strip, and h = slab thickness.

Design Of Slabs
3.2.18 Loads Assigned to Slabs
(1) Own weight of slab:
The weight of the slab per unit area is estimated by multiplying the thickness
of the slab h by the density of the reinforced concrete.
(2) Weight of slab covering materials:
This weight per unit area depends on the type of finishing which is usually
made of
- Sand fill with a thickness of about 5 cm,
0.05 × 1.80 t/m2
- Cement mortar, 2.5 cm thick.
0.025 × 2.10 t/m2
- Tiling
0.025 × 2.30 t/m2
- A layer of plaster about 2 cm in thickness.
0.02 × 2.10 t/m2
(3) Live Load:
It depends on the purpose for which the floor is constructed. Shows typical
values used by the Uniform Building Code (UBC).
Note: During the analysis of the 3d frame of the building in this project, we
assumed a uniformly distributed planar live load of 5kN per meter square (as the
building falls in the whole sale stores category.

Design Of Slabs
3.2.1 Plans showing the assigned slab names and direction for different stories:-
Fig 3.1.1 Elevation plan for slab of ground floor
Fig 3.1.2 Elevation plan for slab on first floor

Design Of Slabs
Fig 3.1.3 Elevation plan for slabs on second floor

Design Of Slabs

Design Of Slabs
3.2 Steps for design of two way solid slab:
 Find the moment coefficients in each slab:
 For continuous edges ( -Ve moments ):
2
2
bL.utW.)aC(b)ve-M(
aL.utW.)aC(a)ve-M(
neg
neg


 Span moments ( +Ve moments ):
2
2
bL]uW.)bC(W.)b(C[b)veM(
aL]uW.)aC(W.)a(C[a)veM(
LLLuddL
LLLuddL


 For discontinuous edges ( -Ve moments ):
3/b)veM(b)ve-M(
3/a)veM(a)ve-M(


 Effective Depth (d):
st
dc.c
u
hd 
 Percentage of steel (ρ):
mm1000b,dbρsA
minρ
yf
ωρ
0.113
yf
ρFor
mm450
s2h
dρ
)s(A
barsbetweenSpacingS
0.113
yf
ρCheck
d
sh
0.002minρ
dyf840
uM
ρ
'
c
'
c
'
c
f
f
f
barone
2














OK:
M(-Ve)
+
--
M(+Ve)

Design Of Slabs
3.2 Data for design:-
Firstly: Defining the sample slab for design illustration
Secondly: structural analysis design of the Unit
3.2.1 The slabs S2 and S8 are taken as design samples which are assumed to be solid slab , as
shown in fig given below:
3.2.1.2 Design Concept:
One-way solid slabs are designed as a number of independent 1 m wide strips
which span in the short direction and supported on crossing beams.
 Practical rules:
 THE overall thickness of a slab shall not be less than 7.5 cm, the top
surface of centering shall be given a camber of 7mm per meter span
subject to maximum of 4.5 cm.
 Reinforcements: the minimum reinforcement in slabs in either
direction shall be not less than 0.15 percent of the gross sectional area
of the concrete and which may be 0.12 percent where high yield
strength deformed bars .

Design Of Slabs
3.3 Firstly, let’s consider Slab S2 (Two-Way Slab) :
Fig 3.3 shows Slab S2 which is a two-way slab
3.3.1 Determine the thickness of the solid slab S2 :
mm.
)
.
(
.
uh
slab)way solid-(two..
7.50
6.50
mifelse
way slab)-(onethen.
Lb
La
mif
mm
)
M
(
lb
sh
03183
860
6
34
1000507
50850
50
100
6
34









USE hs =200mm _________________________eq 3.1
169
2
12
25200 

d
stdc.cuhd
3.3.1.2 Calculation of loads on slabs S2:
2KN/m17.67uW
.77741m/KNW
LL1.7DL.uW
27.77KN/m2.9724W
LL
D
flooring
h
W c
s
D





47124
41
1000
200
1000


Design Of Slabs
3.3.2 Moments at short direction:
 For Discontinuous edge
m.KN.
.
M
a)veM(
M
M
238
3
724
1
3
1
3
2
1


 For mid-span
m.KN..]....[
La]
ul
W
ll
)Ca(UDW
Dl
[(Ca)
2
M
724250686040078100290
2


 For Continuous Edge
m.KN...).(M
aLutWneg)Ca(
3
M
5836250667170490
3
2


Slab Case m DL LL -Ve
S2 8 0.85
Ca=0.029 Ca=0.040 Ca=0.049
Cb=0.017 Cb=0.022 Cb=0.046
Table (3-4) moment coefficients
3.3.3 Moments at Long direction: -
d=200-25-1.5*12=157mm
 For continuous edge
m.KN...).(M
aLutWneg)Cb(M4
7245250767170460
2
4 

 For Mid-span
m.KN..]....[M
La]
ul
W
ll
)Cb(
uD
W
Dl
[(Cb)M
5
5
7218250786022078100170
2


46
MM 

Design Of Slabs
3.4 Design for flexure:-
3.4.1 Reinforcement At Short direction:
A . (La-discontinuous): (-ve) M1
'12/320mm/mUse
320mmSUse
hsmm.
.
S
2D
sb
A
450mm
2hs
d
sb
A
S
mm.dbstA
valuenewforneed)(NOO.K...
minFy
Fc
usethen
.
fc
yf
for
minUse
reqmin
control..
d
sh
.min
.
.
dFy
uM
:check







































29377
13000240
113
113
4
212
4
2299130100000230
1130030
25
420
00230
1130
00230
169
200
00200020
00080
2169420840
610238
2840
610

Design Of Slabs
B. At Short direction (La-middle) : (+ve) M2
12/270mmUse
270mmUse
mm.
.d
/d
S
450mm
2hs
d
barones
A
S
O.K...
.
fc
yf
requse,minreq
..
d
sh
.min
.req
2
:check
.








59278
16900240
1134
1130040
25
420
00240
1130
00230
169
200
00200020
00240
2169420840
6
10724




















C. At short direction (La right-edge continuous): M3 (-ve)
12/180mmUse
7.185
1690036.0
113
113.0060.0
25
420
0036.0
use,
min
0023.0
min
0036.0
2169420840
:
6
1058.36




mmS
reqreq
req
check











Design Of Slabs
3.4.2 Reinforcement At long direction
A. (Lb-edge) continuous: M6-ve
12/100mmUse
82.102
157005.0
113
O.K113.0084.0
25
420
005.0
:
0025.0
157
200002.0002.0
min
005.0
2157420840
61072.45



mmS
check
d
hs
req











B. At long direction (Lb-mid span): M5+ve
12/280mmUse
287
1570025.0
113
0025.0
min
use
min
,0025.0
min
0021.0
2157420840
61072.18





mmS
req
req










C. At long direction (Lb-cont edge): M4-ve
12/100mmUse
useHence
MM

64


Design Of Slabs
Direction sec )/(
u
M mKN d(mm) min
 req use (req)S used
S
short
1 8.23
169
0.0023 0.0008 0.0023 377 320
2 24.7 0.0023 0.0024 0.0024 278.5 270
3 36.58 0.0023 0.0036 0.0036 185.7 180
long
4 45.72
157
0.0025 0.005 0.005 102.8 100
5 18.72 0.0025 0.0021 0.0025 287 280
6 45.72 0.0025 0.005 0.005 102.8 100
Table (3-4) two- way slabs reinforcement

Design Of Slabs
3.5 Design of one-way slab :
3.5.1.1 Minimum Reinforcement Ratio
According to ACI Code 10.5.4, the minimum flexural reinforcement is not to
be less than the shrinkage reinforcement, or A b h s 0.0018 min ³ .
3.5.1.2 Spacing of Flexural Reinforcement Bars
Based on ACI 10.5.4, flexural reinforcement is to be spaced not farther than
three times the slab thickness, nor farther apart than 45 cm, center-to-center.
3.5.1.3 Spacing of Shrinkage Reinforcement Bars
Based on ACI 7.12.2.2, shrinkage reinforcement is to be spaced not farther
than five times the slab thickness, nor farther apart than 45 cm, center-to-
center.
3.5.1.4 Now Let’s consider Slab S8 (One-Way Slab)
Fig 3.5 shows one –way slab named S8
 Determine the thickness of the solid slab :
mm.
)
.
(
.
sh
slab)way solidone(..
m.
m.
m
.
b
L
aL
m
mm
)
m
6
(34
b
L
sh
8116
3010
6
34
1000306
503010
306
901
50
100









 Use slab thickness from largest span hs= 200mm ( Eq 3.1 )

Design Of Slabs
3.5.2 Calculation of loads on slabs S8:
2KN/m17.67uW
.77141uW
m/KNW
LL1.7DL.uW
2m7.77KN/2.9724W
LL
D
floowing
h
W c
s
D






471
24
41
1000
200
1000


3.5.3 Moments at short direction: -
m.KN.
..
2
9
nLuW
M 087
9
29167172
7



 For Mid-span
m.KN.
..nLuW
M 54
14
2916717
14
2
8




m.KN.
..nLuW
M 652
24
2916717
24
2
9




Reinforcement:3.5.4 Minimum Steel
002350
310372
170
200
0020
0020
170
2
10
25200
.min
.min
)(.min
)
d
sh
(.min
mmd










Design Of Slabs
A . Reinforcement For edge-moment M7:
002350
000640
420
25
01080
01090
181
0108036211
01080
217010002590
610087
087
7
1000
.min
min..
fy
'
cf
f
.
.
).(.
.
.
.
uK
d'
cf
u
M
uK
m.KN.M
Use
2
















190/m'/5Ues
mmmm.
.
reqS
mm.
2D
S
A
S
A
bA
S
m
mm..
S
A
db
S
A
S



1904196
4
1000578
2578
4
210
4
1000
2
53991000170002350










B. Reinforcement for Mid-span:
 
0.00235min
min0.00041.
yf
'
cf
ρ
0.0070
1.18
1
ω
0.0089
951000200.9
101.45
uK
kN.m.
8
M
Ues
).(.
2
6













420
25
00700
54
006903621

Design Of Slabs
dbsA
10/190/m'5Use
mmmm.
.
.
S
A
bA
S
'm
mm..A
S
S
S


1904196
5399
1000578
1000
53991000170002350
2







C . Reinforcement For edge-moment M9 :
10/200/m'5Use
mmmm.S
'm
mm..db
S
A
.minUse
min..
fy
'
cf
.
.
).(.
.
.
.
uK
m.KN.
9
* M





2004196
2
53991000170002350
002350
00020
420
25
00410
00410
181
0040036211
00400
217010002590
610652
652













Design Of Slabs
3.5.5 Secondary reinforcement:
mm/m'120/10SUse
mm120SUse
67.125
400
100027.50
S
27.50
4
814.3
4
D
1000
S
m'
2mm40020010000.002sA
sbh0.002sA
2
22













mm
mmbsA
t
s
A
b
s
A
t
t
Section 1 2 3
uM 7.08 4.5 2.65
uK 0.0108 0.0069 0.0040
ω 0.0109 0.0070 0.0049
ρ 0.00235 0.00235 0.00235
/msA 399.5 399.5 399.5
(req)S 196.4 196.4 196.4
(used)
S 190 190 190
Table (3-5) reinforcement of one-way solid slab

‫ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬‫ــ‬‫ـــــــــــــــــــــــــــ‬‫ــــــــ‬‫ـــــــــــــــــــــــــــ‬‫ـ‬
50‫ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬‫ـــــــــــــــــــــــــــ‬‫ـــــــــــــــــــــــــــــــــــــــــــــــــ‬
Design Of Beams
4. Design of Beams
4.1 Introduction
The beams are a basic component of reinforced concrete structures , the beams
carries and transfers the loads from the slabs and walls to the columns and then to the
foundations. The beams should be correctly restrained and appropriate studies and analysis
should be done to overcome and resist the moments and shrinkage and other deformations
resulted upon loading. The explanation of design is shown firstly through formulas and
then a sample (continuous beam) is taken and is designed, the related moments and shears
forces acting upon it is calculated through Autodesk Robot structural analysis
4.2 Structural Theory of beams:
4.2.1 Types of beams:
There are many ways in which the beams may be supported, some of the more
common methods are given below ,
Fig. 4.1
The first beam in Fig is called a simply supported, or simple beam. It has Supports near its
ends, which restrain it only against vertical movement. The ends of the beam are free to
rotate. When the loads have a horizontal component, or when change in length of the beam
due to temperature may be important, the Supports may also have to prevent horizontal
motion. In that case, horizontal restraint at one support is generally sufficient. The distance
between the supports is called the span. The load carried by each support is called a reaction.

‫ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬‫ــ‬‫ـــــــــــــــــــــــــــ‬‫ــــــــ‬‫ـــــــــــــــــــــــــــ‬‫ـ‬
51‫ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬‫ـــــــــــــــــــــــــــ‬‫ـــــــــــــــــــــــــــــــــــــــــــــــــ‬
Design Of Beams
The beam which is a cantilever. It has only one support, which restrains it from rotating or
moving horizontally or vertically at that end. Such a support is called a fixed end.
When a beam extends over several supports, it is called a continuous beam
For flexural design of R/C rectangular section beams, there is a number of steps procedure
and equations provided by ultimate strength design method according to ACI-code. The large
number of equations and fork of solution steps causes a lot of confusion and boredom for
student or designer
4.2.2 Scope of Usage:
Concrete beams are widely used as a primary members to con-struct buildings.
Robot Structural analysis is widely used as a structural analysis and design program.
Sometimes, to give design more confidently, we need to compare the results of program
with the results of manual calculations. Most common beams, which are rectangular
section and T-section, apply vertical loads (dead and live loads).
Beams, like that, will be subjected to the bending moment, shear force and torsional
moment. This study focuses on beams of rectangular section considering bending
moment only. Flexural created by bending moment, makes the beam in case of tension
or com-precision failure.
4.2.3 Relation of Reinforcement place with section properties on loading:
 In case of tension failure, provided reinforcement ratio (ρ) at tension zone is
less than balanced reinforcement ratio ρbal . So that, steel will reach to the yield
stress ( ) and strain ( ). While, concrete at compression zone has not yet
reached to the ultimate strain ( =0.003).
 In case of compression failure, provided (ρ) at tension zone is greater than ρbal .
Concrete at compression zone will reach ultimate stress ( ult) and strain ( ult),
While steel has not yet reached . For each case, there is a number of design
equations derived. To identify those equations, textbooks can be reviewed for
the principles of the design of reinforced concrete.

Design and analysis of reinforced concrete multistory commercial building using ACI 318-08 by robot structural analysis and by manual method

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