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/ith this program it is possible for the user to design basic structural parts such as slab
beam column and footing. lso the program is based on the merican Concrete Institute
Code. ,he ultimate goal of this program is that users can analy-e their own designs using
this program and determine structural proportions of their design idea.
,he rapid development of the computer in the last decade has resulted in rapid adoption
of Computer *tructural esign *oftware that has now replaced the manual computation.
,his has greatly reduced the comple%ity of the analysis and design process as well as
reducing the amount of time re$uired to finish a pro0ect.
1.2 Statement of the Study
,his study involves the development of design software for #eam Column 'ooting and
*taircase.
1.3 Objective of the Study
1. ,o ma&e the design Calculation simple easier and rapid.
. ,o get &nowledge and to use the merican Concrete Institute Code (CI 21834).
2. ,o develop a software for the design of several structural element (#eam Column
*tair 'ooting) according to the provision 5 procedure of the merican Concrete
Institute Code (CI 21834).
6. ,o get economical section without any arithmetic mista&es.
1.4 Computer oft!are
*oftware is a program that enables a computer to perform a specific tas& as opposed to
the physical components of the system (hardware).
,his includes application software such as a word processor which enables a user to
perform a tas& and system software such as an operating system which enables other
software to run properly by interfacing with hardware and with other software. 7ractical
computer systems divide software into three ma0or classes system software
programming software and application software although the distinction is arbitrary and
often blurred. Computer software has to be 9loaded9 into the computer:s storage (such as
a hard drive memory or R!). ;nce the software is loaded the computer is able to
e%ecute the software. Computers operate by e%ecuting the computer program. ,his
involves passing instructions from the application software through the system software
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to the hardware which ultimately receives the instruction as machine code. "ach
instruction causes the computer to carry out an operation moving data carrying out a
computation or altering the control flow of instructions.
1." Soft!are #n$ineerin$
*oftware engineering is the study and an application of engineering to the design
development and maintenance of software.
,ypical formal definitions of software engineering are
• Research design develop and test operating systemslevel software compilers
and networ& distribution software for medical industrial military
communications aerospace business scientific and general computing
applications.
• ,he systematic application of scientific and technological &nowledge methods
and e%perience to the design implementation testing and documentation of
software.
software engineer is a licensed professional engineer who is schooled and s&illed in the
application of engineering discipline to the creation of software. software engineer is
often confused with a programmer but the two are vastly different disciplines. /hile a
programmer creates the codes that ma&e a program run a software engineer creates the
designs the programmer implements. #y law no person may use the title <engineer= (of
any type) unless the person holds a professional engineering license from a state licensing
board and are in good standing. software engineer is also held accountable to a specific
code of ethics.
1.% Structural &ei$n
*tructural design is the methodical investigation of the stability strength and rigidity of
structures. ,he basic ob0ective in structural analysis and design is to produce a structure
capable of resisting all applied loads without failure during its intended life. ,he primary
purpose of a structure is to transmit or support loads. If the structure is improperly
designed or fabricated or if the actual applied loads e%ceed the design specifications the
device will probably fail to perform its intended function with possible serious
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conse$uences. wellengineered structure greatly minimi-es the possibility of costly
failures
1.' Structural dei$n proce
structural design pro0ect may be divided into three phases i.e. planning design and
construction.
(lannin$) ,his phase involves consideration of the various re$uirements and factors
affecting the general layout and dimensions of the structure and results in the choice of
one or perhaps several alternative types of structure which offer the best general solution.
,he primary consideration is the function of the structure. *econdary considerations such
as aesthetics sociology law economics and the environment may also be ta&en into
account. In addition there are structural and constructional re$uirements and limitations
which may affect the type of structure to be designed.
&ei$n) ,his phase involves a detailed consideration of the alternative solutions defined
in the planning phase and results in the determination of the most suitable proportions
dimensions and details of the structural elements and connections for constructing each
alternative structural arrangement being considered.
Contruction) ,his phase involves mobili-ation of personnel> procurement of materials
and e$uipment including their transportation to the site and actual onsite erection.
uring this phase some redesign may be re$uired if unforeseen difficulties occur such as
unavailability of specified materials or foundation problems.
1.* #n$ineerin$ &ei$n (roce
,he engineering design process is a series of steps that engineers follow to come up with
a solution to a problem. !any times the solution involves designing a product (li&e a
machine or computer code) that meets certain criteria and?or accomplishes a certain tas&.
efine the criteria and constraints of a design problem with sufficient precision to
ensure a successful solution ta&ing into account relevant scientific principles and
potential impacts on people and the natural environment that may limit possible
solutions.
"valuate competing design solutions using a systematic process to determine how
well they meet the criteria and constraints of the problem.
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naly-e data from tests to determine similarities and differences among several
design solutions to identify the best characteristics of each that can be combined
into a new solution to better meet the criteria for success.
evelop a model to generate data for iterative testing and modification of a
proposed ob0ect tool or process such that an optimal design can be achieved.
"ngineering design process illustrated briefly in flow chart below
"ngineers do not always follow the engineering design process steps in order one after
another. It is very common to design something test it find a problem and then go bac&
to an earlier step to ma&e a modification or change to your design. ,his way of wor&ing is
called iteration.
1.+ ,eaon for developin$ thi Soft!are
4
aed on reult and data
mae dei$n chan$e/
prototype/ tet a$ain and
revie! ne! data
&evelop and (rototype
raintorm/ #valuate and
Solution eet Solution eet ,euirement
(artiall or ot at ll
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#eam column footing stair are the important elements of the whole building. "ngineers
should have to be careful and sincere to give an economic design within minimum time.
,his software will serve following purpose>
1. It will not only give accurate result but also save time and money.
. esign can be completed $uic&ly hence saving time it will increase the efficiency
of an engineer.
2. It will reduce the error due to arithmetic mista&es some error of mathematic
number and minimi-e the amount of manually handled data.
6. @arious types of building elements and mist of the cases the engineers perform
the design from their e%perience which is not accurate and not economical. ,his
software will reduce the labor and time and will ensure economical design.
1.15 ,eaon for uin$ 6iual Studio 251" and C Sharp
CA (C *harp) is an elegant simple typesafe ob0ectoriented language that allows
enterprise programmers to build a breadth of applications. It is a user friendly language.
CA is better than CBB because
• It has a huge standard library with so much useful stuff that:s wellimplemented
and easy to use.
• It allows for both managed and native code bloc&s.
• It allows you to treat classmethods: signatures as free functions (i.e. ignoring the
statically typed this pointer argument) and hence create more dynamic and fle%ible
relationships between classes.
• ssembly versioning easily remedy problems.
!icrosoft @isual *tudio is an integrated development environment (I") from !icrosoft.
It is used to develop computer programs for !icrosoft /indows as well as web sites
web applications and web services. @isual *tudio uses !icrosoft software development
platforms such as /indows 7I /indows 'orms /indows 7resentation 'oundation
/indows *tore and !icrosoft *ilverlight. It can produce both native code and managed
code. It has easy code navigation fast builds and $uic& deployment. @isual *tudio
increases productivity and ma&es it easy to do wor& alone or as part of a larger team.
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@isual CA is an implementation of the CA language by !icrosoft. @isual *tudio supports
@isual CA with a fullfeatured code editor compiler pro0ect templates designers code
wi-ards a powerful and easytouse debugger and other tools. ,he .N", 'ramewor&
class library provides access to many operating system services and other useful well
designed classes that speed up the development cycle significantly.
E
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Chapter-2
,einforced Concrete Structure
2.1 General
Concrete is one of the most popular materials for buildings because it has high
compressive strength fle%ibility in its form and it is widely available. ,he history of
concrete usage dates bac& for over a thousand years. Contemporary cement concrete has
been used since the early nineteenth century with the development of 7ortland cement.
espite the high compressive strength concrete has limited tensile strength only about
ten percent of its compressive strength and -ero strength after crac&s develop. In the late
nineteenth century reinforcing materials such as iron or steel rods began to be used to
increase the tensile strength of concrete. ,oday steel bars are used as common reinforcing
material. +sually steel bars have over 133 times the tensile strength of concrete> but the
cost is higher than concrete. ,herefore it is most economical that concrete resists
compression and steel provides tensile strength. lso it is essential that concrete and steel
deform together and deformed reinforcing bars are being used to increase the capacity to
resist bond stresses.
dvantages of reinforced concrete can be summari-ed as follows (Fassoun 1GG8).
1. It has a relatively high compressive strength.
. It has better resistance to fire than steel or wood
2. It has a long service life with low maintenance cost
6. In some types of structures such as dams piers and footing it is the most
economical structural material.
4. It can be cast to ta&e any shape re$uired ma&ing it widely used in precaststructural components.
lso disadvantages of reinforced concrete can be summari-ed as follows
1. It has a low tensile strength (-ero strength after crac&s develop).
. It needs mi%ing casting and curing all of which affect the final strength of
concrete.
2. ,he cost of the forms used to cast concrete is relatively high. ,he cost of form
material and artisanry may e$ual the cost of concrete placed in the forms.
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6. It has a lower compressive strength than steel (about 1?13 depending on material)
which re$uires large sections in columns of multistory buildings.
4. Crac&s develop in concrete due to shrin&age and the application of live loads.
2.2 Safety
structure must be safe against collapse> strength of the structure must be ade$uate for
all loads that might act on it. If we could build buildings as designed and if the loads and
their internal effects can be predicted accurately we do not have to worry about safety.
#ut there are uncertainties in
• ctual loads>
• 'orces?loads might be distributed in a manner different from what we assumed>• ,he assumptions in analysis might not be e%actly correct>
• ctual behavior might be different from that assumed etc.
'inally we would li&e to have the structure safe against brittle failure (gradual failure
with ample warning permitting remedial measures is preferable to a sudden or brittle
failure).
2.3 uildin$ Code ,euirement for Structural Concrete
#uildings must be designed and constructed according to the provisions of a building
code which is a legal document containing re$uirements related to such things as
structural safety fire safety plumbing ventilation and accessibility to the physically
disabled. building code has the force of law and is administered by a governmental
entity such as a city a county or for some large metropolitan areas a consolidated
government. #uilding codes do not give design procedures but specify the design
re$uirements and constraints that must be satisfied. ;f particular importance to the
structural engineer is the prescription of minimum live loads for buildings. /hile the
engineer is encouraged to investigate the actual loading conditions and attempt to
determine realistic values the structure must be able to support these specified minimum
loads. !any countries have their own structural design codes codes of practice or
technical documents which perform a similar function.It is necessary for a designer to
become familiar with local re$uirements or recommendations in regard to correct
practice. In this chapter some e%amples are given occasionally in a simplified form in
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order to demonstrate procedures. ,hey should not be assumed to apply to all areas or
situations. Fowever the +niform #uilding Code (+#C) and other model codes are
adapted by 0urisdictions such as Cities or *tates as governing codes. !aterial and
methods are tested by private or public organi-ations. ,hey develop share and
disseminate their result and &nowledge for adoption by 0urisdictions. ,he merican
Concrete Institute (CI) is leading the development of concrete technology. ,he CI has
published many references and 0ournals. #uilding Code Re$uirement for *tructural
Concrete (CI 218 Code) is a widely recogni-ed reinforced concrete design and
construction guide. lthough the CI Code does not have official power of enforcement
it is generally adapted as authori-ed code by 0urisdictions not only in +nited *tates but
also many countries. ,he CI218 Code provides the design and construction guide of
reinforced concrete. CI has been providing new codes depending on the change of
design methods and strength re$uirement.
2.4 Safety (roviion of the CI Code
oad factors are applied to the loads and a member is selected that will have enough
strength to resist the factored loads. In addition the theoretical strength of the member is
reduced by the application of a resistance factor. ,he criterion that must be satisfied in the
selection of a member is
'actored *trength H 'actored oad
In this e%pression the factored load is actually the sum of all wor&ing loads to be resisted
by the member each multiplied by its own load factor. 'or e%ample dead loads will have
load factors that are different from those for live loads. ,he factored strength is the
theoretical strength multiplied by a strength reduction factor. "$uation (1.2) can therefore be written as
Nominal *trength *trength Reduction 'actor H oad oad 'actors
*ince the factored load is a failure load greater than the actual wor&ing loads the load
factors are usually greater than unity. ;n the other hand the factored strength is a
reduced usable strength and the resistance factor is usually less than unity. ,he factored
loads are the loads that bring the structure or member to its limit.
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2." &ei$n ethod of ,einforced Concrete Structure
,wo ma0or calculating methods of reinforced concrete have been used from early 1G33Js
to current. ,he first method is called /or&ing *tress esign (/*) and the second is
called +ltimate *trength esign (+*). /or&ing *tress esign was used as the principal
method from early 1G33Js until the early 1GD3Js. *ince +ltimate *trength esign method
was officially recogni-ed and permitted from CI 2184D the main design method of
CI 218 Code has gradually changed from /* to +* method. ,he program of this
thesis is based on CI 21834 Code /hich published in 334.
2.".1 Chan$e of &ei$n ethod accordin$ to CI 31* Code (7C 1GGG).
CI 2184D +* was first introduced (1G4D)
CI 218D2 /* and +* were treated on e$ual basis.
CI 218E1 #ased entirely on strength !ethod (+*) /* was called lternate esign
!ethod (!).
CI 218EE ! relegated to ppendi% # CI 2188G ! bac& to ppendi%
CI 218G4 ! still in ppendi% +nified esign 7rovision was introduced in
ppendi% #
CI 2183 ! was deleted from ppendi% (CI 33).
2.".2 0he 7orin$ Stre &ei$n 87S&9
,raditionally elastic behavior was used as basis for the design method of 1D reinforced
concrete structures. ,his method is &nown as /or&ing *tress esign (/*) and also
called the lternate esign !ethod or the "lastic esign !ethod or llowable stress
design. ,his design concept is based on the elastic theory that assumes a straightline
stress distribution along the depth of the concrete section. ,o analy-e and design
reinforced concrete members the actual load under wor&ing conditions also called
service load condition is used and allowable stresses are decided depending on the safety
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factor. 'or e%ample allowable compressive bending stress is calculated as 3.64fJ c. If the
actual stresses do not e%ceed the allowable stresses the structures are considered to be
ade$uate for strength. ,he /* method is easier to e%plain and use than other method
but this method is being replaced by the +ltimate *trength esign method. CI 218 Code
treats the /* method 0ust in a small part.
,he wor&ing stress method may be e%pressed by the following
f K allowable stresses (f allowable) (1)
where f L an elastically computed stress such as by using the fle%ure formula f L !c?I
for beam.
f allow L limiting stress prescribed by a building code as a percentage of the compressive
strength f cM for concrete or of the yield stress f y for the steel reinforcing bars.
2.".3 0he :ltimate Stren$th &ei$n 8:S&9
,he +ltimate *trength esign method also called *trength esign !ethod (*!) is
based on the ultimate strength when the design member would fail. *ince 1GE1 the CI
Code has been totally a strength code with <strength= meaning ultimate. *elect concrete
dimensions and reinforcements so that the member strength are ade$uate to resist forces
resulting from certain hypothetical overload stages significantly above loads e%pected
actually to occur in service. ,he design concept is &nown as <strength design.= #ased on
strength design the nominal strength of a member must be calculated on the basis of
inelastic behavior of material. In other words both reinforcing steel and concrete behave
in elastically at ultimate strength condition.
,he strength design method may be e%pressed by the following
*trength provide H *trength re$uired to carry factored loads
where the <strength provided= such as moment strength is computed in accordance with
rules and assumptions of behavior prescribed by a building code and the <strength
re$uired= is that obtained by performing a structural analysis using the factored loads.
,he design procedure is roughly as follows
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!ultiply the wor&ing loads by the load factor to obtain the failure loads.
etermine the cross sectional properties needed to resist failure under these loads. (
member with these properties is said to have sufficient strength and would be at the verge
of failure when sub0ected to the factored loads.)
7roportion your members that have these properties.
#asic ssumptions for Concrete in +ltimate *trength esign method (CI)
l. *ections perpendicular to the a%is of bending that arc plane before bending remains
plane after bending.
. perfect bond e%ists between the reinforcement and the concrete such that the strain in
the reinforcement is e$ual to the strain in the concrete at the same level.
2. ,he strains in both the concrete and reinforcement are assumed to be directly
proportional to the distance from the neutral a%is (CI 13..).
6. Concrete is assumed to fail when the compressive strain reaches 3.332 (CI 13..2).
4. ,he tensile strength of concrete is neglected (CI 13..4).
D. ,he stresses in the concrete and reinforcement can be computed from the strains using
stressstrain curves for concrete and steel respectively.
E. ,he compressive stressstrain relationship for concrete may be assumed to be
rectangular trape-oidal parabolic or any other shape that results in prediction of strength
in substantial agreement with the results of comprehensive tests (CI 13..D). CI 13..E
outlines the use of a rectangular compressive stress distribution which is &nown as the
/hitney rectangular stress bloc&.
8. Reinforcing steel will yield when strain is e$ual to "y and stress after yield is always f y.
2.% ;oad
oads that act on structures can be divided into three general categories
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2.%.1 &ead ;oad) ead loads are those that are constant in magnitude and fi%ed in
location throughout the lifetime of the structure such as floor fill finish floor and
plastered ceiling for buildings and wearing surface sidewal&s and curbing for bridges.
2.%.2 ;ive ;oad) ive loads are those that are either fully or partially in place or not
present at all may also change in location> the minimum live loads for which the floors
and roof of a building should be designed are usually specified in building code that
governs at the site of construction
2.%.3 #nvironmental ;oad) "nvironmental oads consist of wind earth$ua&e and
snow loads. *uch as wind earth$ua&e and snow loads.
,he load factors are 1.E for live load and 1.6 for dead load. ;ther factors are given in
,able
0able 2-1) <actored load combination for determinin$ reuired tren$th :
Condition <actored load or load effect :
#asic + L 1.6 B 1.E
/inds
+ L 3.E4(1.6 B 1.E B 1.E/)
+ L 3.G B 1.2/
+ L 1.6 B 1.E
"arth$ua&e
+ L 3.E4(1.6 B 1.E B 1.8E")
+ L 3.G B 1.62"
+ L 1.6 B 1.E
"arth pressure
+ L 1.6 B 1.E B 1.EF
+ L 3.G B 1.EF
+ L 1.6 B 1.E
*ettlement creep shrin&age or temperature
change effects
+ L 3.E4(1.6 B 1.6, B 1.E)
+ L 1.6( B ,)
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2.' ,euired Stren$th
,he re$uired strength + is e%pressed in terms of factored loads or related internal
moments and forces. 'actored loads are the loads specified in the general building code
multiplied by appropriate factors. ,he factor assigned is influenced by the degree of
accuracy to which the load effect can be determined and the variation which might be
e%pected in the load during the lifetime of the structure. ead loads are assigned a lower
load factored than live load because they can be determined more accurately. oad factors
also account for variability in the structural analysis used to compute moments and
shears. ,he code gives load factors for specific combinations of loads. In assigning
factors to combinations of loading some consideration is given to the probability of
simultaneous occurrence. /hile most of the usual combinations of loadings are included
the designer should not assume that all cases are covered. @arious load combinations must
be considered to determine the most critical design condition. ,his is particularly true
when strength is dependent on more than one load effect such as strength for combined
fle%ure and a%ial load or shear strength in members with a%ial load. *ince the CI 218
#uilding Code is a national code it has to conform to the International #uilding Code
I#C31 and in turn be consistent with the *C"E *tandard on !inimum esign oads
for #uildings and ;ther structures. ,hese two standards contain the same probabilistic
values for the e%pected safety resistance factors OiRn where O is a strength reduction
factor depending on the type of stress being considered in the design such as fle%ure
shear or compression etc.
'actored oad Combinations for etermining Re$uired *trength + in CI Code
+ L 1.6( B ') (1)
+ L 1.( B ' B ,) B 1.D ( B F) B 3.4(r or * or R) ()
+ L 1. B 1.D (r or * or R) B (1.3 or 3.8/) (2)
+ L 1. B 1.D/ B 1.3 B 3.4(r or * or R) (6)
+ L 1. B 1.3" B 1.3 B 3.* (4)
+ L 3.G B 1.D/ B 1.DF (D)
+L 3.G B 1.3" B 1.DF (E)
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/here
L ead oad
L ive oad
" L"arth$ua&e oad
/L /ind oad
,L *elf*training force such as Creep *hrin&age 5 ,emperature "ffect
FLoad due to the weight 5 lateral pressure of soil and water in soil
r L Roof oad
RL Rain oad
*L *now oad
'L ateral fluid pressure oad
ue Regard is to be given to sign in determining + for combinations of loadings as one
type of loading may produce effects of opposite sense to that produced by another type.
,he load combinations with 3.G are specifically included for the case where a higher
dead load reduces the effects of other loads. ,he loading case may also be critical for
tension controlled column sections. In such a case a reduction in a%ial load and an
increase in moment may result in critical load combination.
"%cept for
,he load factor on in "$uation (2) to (4) shall be permitted to be reduced to 3.4 e%cept
for garages areas occupied as places of public assembly and all areas where the live load
is greater than 133 lb?ft.
/here wind load / has not been reduced by a directionality factor it shall be permitted
to use 1.2/ in place of 1.D/ in "$uations (6) and (D)
/here earth$ua&e load " is based on servicelevel seismic forces 1.6" shall be used in
place of 1.3" in "$uations (4) and (E).
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,he load factor on F shall be e$ual to -ero in "$uation (D) and (E) if the structural
action due to F counteracts that due to / or ". /here lateral earth pressure provides
resistance to structural actions from other forces. It shall not be included in F but shall be
included in the design resistance.
2.* &ei$n Stren$th
,he strength of a particular structural unit calculated using the current established
procedures is termed <nominal strength.= 'or e%ample in the case of a beam the resisting
moment capacity of the section calculated using the e$uations of e$uilibrium and
properties of concrete and steel is called the <nominal moment capacity= !n of the
section.
,he purpose of the strength reduction factor f are (!acPregor 1GED> and /inter 1GEG)
,o allow for understrength members due to variations in material strengths and
dimensions
,o permit for inaccuracies in the design provisions
,o reflect the degree of ductility and re$uired probability of the member under the load
effects being considered
,o reflect the importance of the member in the structure.
*trength Reduction 'actors ' of the CI Code
,ension controlled sections QQQQQQQQQQQQQ..3.G3
Compression controlled sections
i. !embers with spiral reinforcement QQQQQQ...3.E4
ii. ;ther members QQQQQQQQQQQQQ...3.D4
*hear and torsion QQQQQQQQQQQQQQQQQ..3.E4
#earing on Concrete QQQQQQQQQQQQQQQQ.3.D4
7lain Concrete QQQQQQQQQQQQQQQQQQ...3.44
2.+ Concrete Cover for ,einforcement
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Concrete cover for reinforcement is re$uired to protect the rebar against corrosion and to
provide resistance against fire. ,he thic&ness of cover depends on environmental
conditions and type of structural member. ,he minimum thic&ness of reinforcement cover
is indicated in the drawings or shall be obtained from the relevant code of practice.
#elow are the specifications for reinforcement cover for different structural members in
different conditions.
a) t each end of reinforcing bar net less than 1 inch or 4 mm or less than twice the
diameter of the bar.
b) 'or a longitudinal reinforcing bar in a column not less than 8?4 inch or 63 mm not less
than the diameter of such bar. In case of columns of minimum dimension of 8 in or 3 cm
under whose reinforcing bards do no not e%ceed in or 1 mm a cover of 1 inch or 4
mm to be used.
c) 'or longitudinal reinforcing bars in a beam not less than D?4 inch or 23 mm or less
than the diameter of the bar.
d) 'or tensile compressive shear or other reinforcements in a slab or wall not less than
2?4 inch or 14 mm not less that the diameter of such bar.
e) 'or any other reinforcement not less than 2?4 inch or 14 mm not less than the diameter
of such bar.
f) 'or footings and other principal structural members in which the concrete is deposited
directly against the ground cover to the bottom reinforcement shall be 2 inch or E4 mm.
If concrete is poured on a layer of lean concrete the bottom cover maybe reduced to
inch or 43 mm.
g) 'or concrete surfaces e%posed to the weather or the ground after removal of forms
such as retaining walls grade beams footing sides and top etc. not less than inch or 43
mm.
h) Increased cover thic&ness shall be provided as indicated on the drawings for surfaces
e%posed to the action of harmful chemicals (or e%posed to earth contaminated by such
chemicals) acid al&ali saline atmosphere sulphorone smo&e etc.
i) 'or li$uid retaining structures the minimum cover to all steel shall be 8?4 inch or 63
mm or the diameter of the main bar whichever is greater. In the presence of sea water and
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oils and waters of a corrosive character the covers shall be increased by ?4 inch or 13
mm.
0) 7rotection to reinforcement in case of concrete e%posed to harmful surroundings may
also be given by providing a dense impermeable concrete with approved protective
coatings. In such a case the e%tra cover mentioned in (b) 5 (i) above may be reduced.
&) ,he correct cover shall be maintained by cement mortar cubes (bloc&s) or other
approved means. Reinforcements for footings grade beams and slabs on a subgrade shall
be supported on recast concrete bloc&s as approved by "IC. ,he use of pebbles or stones
shall not be permitted.
l) ,he minimum clear distance between reinforcing bars shall by in accordance with I*
64D S 333 or as shown in drawing.
2.15 Selection of ar and ar Spacin$
Common reinforcing bar si-es range from No. 2 to No. 11 (No. 13 to No. 2D) the bar
number corresponding closely to the number of eighthinches (millimeters) of bar
diameter. ,he two larger si-es No. 16 (No. 62) T1.E4 inch. (62 mm) diameterU and No. 18
(No. 4E) T.4 inch. (4E mm) diameterU are used mainly in columns.
It is often desirable to mi% bar si-es to meet steel area re$uirements more closely. Ingeneral mi%ed bars should be of comparable diameter for practical as well as theoretical
reasons and generally should be arranged symmetrically about the vertical centerline.
!any designers limit the variation in diameter of bars in a single layer to two bar si-es
using say No. 13 and No. 8 (No. 2 and No. 4) bars together but not Nos. 11 and D
(Nos. 2D and 1G). ,here is some practical advantage to minimi-ing the number of
different bar si-es used for a given structure.
Normally it is necessary to maintain a certain minimum distance between ad0acent bars to
ensure proper placement of concrete around them. ir poc&ets below the steel are to be
avoided and full surface contact between the bars and the concrete is desirable to
optimi-e bond strength. CI Code E.D specifies that the minimum clear distance between
ad0acent bars not be less than the nominal diameter of the bars or 1 inch. ('or columns
these re$uirements are increased to 1.4 bar diameters and 1.4 inch.) /here beam
reinforcement is placed in two or more layers the clear distance between layers must not
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be less than 1 inch and the bars in the upper layer should be placed directly above those
in the bottom layer.
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Chapter-3
,evie! of Structural &ei$n on the CI Code
3.1 eam
3.1.1 Introduction
#eams are structural elements carrying transverse e%ternal loads that cause bending
moment shear forces and in some cases torsion across their length. Concrete is strong in
compression and very wea& in tension. *teel reinforcement is used to ta&e up tensile
stresses in reinforced concrete beams. /hen the bending moment acts on the beam
bending strain is produced. ,he resisting moment is developed by internal stresses. +nder positive moment compressive strains are produced in the top of beam and tensile strains
in the bottom. Concrete is a poor material for tensile strength and it is not suitable for
fle%ure member by itself. ,he tension side of the beam would fail before compression
side failure when beam is sub0ected a bending moment without the reinforcement. 'or
this reason steel reinforcement is placed on the tension side. ,he steel reinforcement
resists all tensile bending stress because tensile strength of concrete is -ero when crac&s
develop. In the +ltimate *trength esign (+*) a rectangular stress bloc& is assumed
('ig. 21).
'ig 21 Reinforced rectangular beam (mbrose 1GGE)
s shown 'ig. 21 the dimensions of the compression force is the product f beam width
depth and length of compressive stress bloc&. ,he design of beam is initiated by the
calculation of moment strengths controlled by concrete and steel.
3.1.2 0ype of eam
'ig. 2 shows the most common shapes of concrete beams single reinforced rectangular
beams doubly reinforced rectangular beams ,shape beams spandrel beams and 0oists.In castSinplace construction the single reinforced rectangular beam is uncommon. ,he
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,shape and shape beams are typical types of beam because the beams are built
monolithically with the slab. /hen slab and beams are poured together the slab on the
beam serves as the flange of a ,beam and the supporting beam below slab is the stem or
web. 'or positive applied bending moment the bottom of section produces the tension
and the slab acts as compression flange. #ut negative bending on a rectangular beam putsthe stem in compression and the flange is ineffective in tension. Voists consist of spaced
ribs and a top flange.
'ig. 2 Common shapes of concrete beam (*piegel 1GG8)
3.1.3 ,einforced Concrete eam &ei$n (arameter
a. ,einforcement ,atio)
,he amount of steel reinforcement in concrete members should be limited. ;ver
reinforcing (the placement of too much reinforcement) will not allow the steel to yield
before the concrete crushes and there is a sudden failure. ,he reinforcement ratio in
concrete beam design is the following fraction
= s
,he reinforcement ratio W must be less than a value determined with a concrete strain of
3.332 and tensile strain of 3.336 (minimum). /hen the strain in the reinforcement is
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3.334 or greater the section is tension controlled. ('or smaller strains the resistance factor
reduces to 3.D4 because the stress is less than the yield stress in the steel.)
b. a=imum ,einforcement)
#ased on the limiting strain of 3.334 in the steel x(or c) = 0.375d so
X L Y1 (3.2E4d) to find sma%
,he values of Y1 are presented in the following ,able 6.1
c. inimum ,einforcement)
!inimum reinforcement is provided even if the concrete can resist the tension in order to
control crac&ing.
!inimum re$uired reinforcement
A s=c ΄
bwd #ut not less than
s= w
where
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f y is the yield strength in psi
bw is the width of the web of a concrete ,#eam cross section
d L the effective depth from the top of a reinforced concrete beam to the centroid of the
tensile steel.
d. Cover for ,einforcement)
Cover of concrete over?under the reinforcement must be provided to protect the steel from
corrosion. 'or indoor e%posure 1.4 inch is typical for beams and columns 3.E4 inch is
typical for slabs and for concrete cast against soil 2 inch minimum is re$uired.
e. ar Spacin$)
!inimum bar spacing are specified to allow proper consolidation of concrete around the
reinforcement. ,he minimum spacing is the ma%imum of 1 in a bar diameter or 1.22
times the ma%imum aggregate si-e.
f. #ffective !idth beff )
In case of ,#eams or Pamma#eams the effective slab can be calculated as follows
i. 'or interior ,sections beff is the smallest of
?6 bw B 1Dt or center to center of beams
ii. 'or e%terior ,sections beff is the smallest of
bw B ?1 bw B Dt or bw B (clear distance to ne%t beam)
/hen the web is in tension the minimum reinforcement re$uired is the same as for
rectangular sections with the web width (bw) in place of b.
/hen the flange is in tension (negative bending) the minimum reinforcement re$uired is
the greater value of
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A s=c ΄
bwd or
As=c ΄
b d
where
f y is the yield strength in psi
bw is the width of the web of a concrete ,#eam cross section
beff is the effective flange width
3.1.4 &ei$n (rocedure
,ectan$ular eam
1. ssume the depth of beam using the CI Code reference minimum thic&ness
unless consideration the deflection.
. ssume beam width (ratio of with and depth is about 1).
2. Compute selfweight of beam and design load.
6. Compute factored load
4. Compute design moment (!u).
D. Compute ma%imum possible nominal moment for singly reinforced beam(Z!n).
E. ecide reinforcement type by Comparing the design moment (!u) and the
ma%imum possible moment for singly reinforced beam (Z!n). If Z!n is less
than !u the beam is designed as a doubly reinforced beam else the beam can
be designed with tension steel only.
8. etermine the moment capacity of the singly reinforced section.(concrete
steel couple)
G. Compute the re$uired steel area for the singly reinforced section.
13. 'ind necessary residual moment subtracting the total design moment and the
moment capacity of singly reinforced section.
0-hape eam
1. Compute the design moment (!u).
. ssume the effective depth.
2. ecide the effective flange width (b) based on CI criteria.
6. Compute the practical moment strength (Z!n) assuming the total effective
flange is supporting the compression.
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4. If the practical moment strength (Z!n) is bigger than the design moment
(!u) the beam will be calculated as a rectangular ,beam with the effective
flange width b. If the practical moment strength (Z!n) is smaller than the
design moment (!u) the beam will behave as a true ,shape beam.
D. 'ind the appro%imate lever arm distance for the internal couple.
E. Compute the appro%imate re$uired steel area.
8. esign the reinforcement. G. Chec& the beam width.
G. Compute the actual effective depth and analy-e the beam.
3.2 Column
3.2.1 Introduction
Columns support primarily a%ial load but usually also some bending moments. ,he
combination of a%ial load and bending moment defines the characteristic of column and
calculation method. column sub0ected to large a%ial force and minor moment is design
mainly for a%ial load and the moment has little effect. column sub0ected to significant
bending moment is designed for the combined effect. ,he CI Code assumes a minimal
bending moment in its design procedure although the column is sub0ected to compression
force only. Compression force may cause lateral bursting because of the lowtension
stress resistance. ,o resist shear ties or spirals are used as column reinforcement to
confine vertical bars. ,he comple%ity and many variables ma&e hand calculations tedious
which ma&es the computeraided design very useful.
3.2.2 0ype of Column
Reinforced concrete columns are categori-ed into five main types> rectangular tied
column rectangular spiral column round tied column round spiral column and columnsof other geometry (Fe%agonal shaped ,*haped etc.).
'ig. 22 shows the rectangular tied and round spiral concrete column. ,ied columns have
hori-ontal ties to enclose and hold in place longitudinal bars. ,ies are commonly No. 2 or
No.6 steel bars. ,ie spacing should be calculated with CI Code.
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'ig. 22 Column types
,he columns are also categori-ed into three types by the applied load types. ,he column
with small eccentricity the column with large eccentricity (also called eccentric column)
and bia%ial bending column. 'ig 26 shows the different column types depending on
applied load.
'ig. 26 ,he column types depending on applied load.
"ccentricity is usually defined by location
• Interior columns usually have
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• "%terior columns usually have large eccentricity
• Corner column usually has bia%ial eccentricity.
'ig. 24 "ccentric loaded conditions (*piegel 1GG8)
#ut eccentricity is not always decided by location of columns. "ven interior columns can
be sub0ected by bia%ial bending moment under some load conditions 'ig. 24 shows some
e%amples of eccentric load conditions.
3.2.3 CI Code Safety (roviion for Column
'or columns as for all members designed according to the CI Code ade$uate safety
margins are established by applying load factors to the service loads and strength
reduction factors to the nominal strengths. ,hus for columns Z7n H7u and Z!n [H !u are
the basic safety criteria. 'or most members sub0ect to a%ial compression or compression
plus fle%ure (compression controlled members the CI Code provides basic reduction
factors
ZL 3.D4 for tied columns
Z L 3.E4 for spirally reinforced columns
,he spread between these two values reflects the added safety furnished by the greater
toughness of spirally reinforced columns.
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,here are various reasons why the Z values for columns are lower than those for fle%ure
or shear (3.G3 and 3.E4 respectively). ;ne is that the strength of under reinforced fle%ural
members is not much affected by variations in concrete strength since it depends
primarily on the yield strength of the steel while the strength of a%ially loaded members
depends strongly on the concrete compressive strength. #ecause the cylinder strength of
concrete under site conditions is less closely controlled than the yield strength of mill
produced steel a larger occasional strength deficiency must be allowed for. ,his is
particularly true for columns in which concrete being placed from the top down in a
long narrow form is more sub0ect to segregation than in hori-ontally cast beams.
!oreover electrical and other conduits are fre$uently located in building columns> this
reduces their effective cross sections often to an e%tent un&nown to the designer even
though this is poor practice and restricted by the CI Code. 'inally the conse$uences of a
column failure say in a lower story would be more catastrophic than those of a single
beam failure in the same building.
'or high eccentricities as the eccentricity increases from e b to infinity (pure bending) the
CI Code recogni-es that the member behaves progressively more li&e a fle%ural member
and less li&e a column. s described in Chapter 2 this is ac&nowledged in CI Code
G.2. by providing a linear transition in Z from values of 3.D4 and 3.E4 to 3.G3 as the net
tensile strain in the e%treme tensile steel t increases from f y?"s (which may be ta&en
as 3.33 for Prade D3 reinforcement) to 3.334.
t the other e%treme for columns with very small or -ero calculated eccentricities the
CI Code recogni-es that accidental construction misalignments and other unforeseen
factors may produce actual eccentricities in e%cess of these small design values. lso the
concrete strength under high sustained a%ial loads may be somewhat smaller than the
shortterm cylinder strength. ,herefore regardless of the magnitude of the calculated
eccentricity CI Code 13.2.Dlimits the ma%imum design strength to 3.83cfV7 3 for tied
columns (with ZL 3.D4) and to 3.84Z73 for spirally reinforced columns (with ZL 3.E4)
where P0 is the nominal strength of the a%ially loaded column with -ero eccentricity.
,he effects of the safety provisions of the CI Code are shown in 'ig.2.and represents
the actual carrying capacity as nearly as can be predicted. ,he smooth curve shown
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partially dashed then solid then dashed represents the basic design strength obtained by
ma%imum design load stipulated in the CI Code for small eccentricities i.e. large a%ial
loads as 0ust discussed. t the other end for large eccentricities i.e. small a%ial loads
the
'ig.2D CI safety provisions superimposed on column strength interaction diagram.
CI Code permits a linear transition of\ from 3.D4 or 3.E4 applicable for t K f y?"s (or
3.33 for Prade D3 reinforcement) to 3.G3 at t L 3.334. #y definition t L f y?"s at
the balanced condition. ,he effect of the transition in Z is shown at the lower right end of
the design strength curve.
3.2.4 ehavior of =ially ;oaded Column
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/hen an a%ial load is applied to a reinforced concrete short column the concrete can be
considered to behave elastically up to a low stress of about f c] If the load on the
column is increased to reach its ultimate strength the concrete will reach the ma%imum
strength and the steel will reach its yield strength f y ,he nominal load capacity of the
column can be written as follows
73L 3.84f c]n B stf y
/here n and stL the net concrete and total steel compressive areas respectively.
n L g S st
g L Pross concrete area
,wo different types of failure occur in columns depending on whether ties or spirals are
used. 'or a tied column the concrete fails by crushing and shearing outward the
longitudinal steel bars fail by buc&ling outward between ties and the column failure
occurs suddenly. !uch li&e the failure of a concrete cylinder.
'ig. 2E #ehavior of ,ied and *piral Column
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spiral column undergoes a mar&ed yielding followed by considerable deformation
before complete failure. ,he concrete in the outer shell fails and spalls off. ,he concrete
inside the spiral is confined and provides little strength before the initiation of column
failure hoop tension develops in the spiral and for a closely spaced spiral^ the steel
may yield sudden failure is not e%pected 'igure 2 shows typical load deformation
curves for tied and spiral columns. +p to point a both columns behave similarly. t point
a the longitudinal steel bars of the column yield and the spiral column shell spalls off
after the factored load is reached a tied column fails suddenly (curve b) whereas a spiral
column deforms appreciably before failure (curve c).
3.2." ia=ial endin$
,he design of eccentrically loaded columns using the strain compatibility method of
analysis described re$uires that a trial column be selected. ,he trial column is then
investigated to determine if it is ade$uate to carry any combination of 7 u and !u that may
act on it should the structure be overloaded if 7u and !u from the analysis of the
structure when plotted on a strength interaction diagram such as 'ig. 2E fall within the
region bounded by the curve labeled 9CI design strength.9 'urthermore economical
design re$uires that the controlling combination of 7u and !u be close to the limit curve.
If these conditions are not met a new column must be selected for trial. ,his !ethod
permit rectangular or s$uare columns to be designed if bending is present about only one
of the principal a%es. ,here are situations by no means e%ceptional in which a%ial
compression is accompanied by simultaneous bending about both principal a%es of the
section. *uch is the case for instance in corner columns of buildings where beams and
girders frame into the columns in the directions of both walls and transfer their end
moments into the columns in two perpendicular planes. *imilar loading may occur at
interior columns particularly if the column layout is irregular.
,he situation with respect to strength of bia%ially loaded columns is shown in 'ig. 28.
et and _ denote the directions of the principal a%es of the cross section. In 'ig. 28(a)
the section is shown sub0ect to bending about the _ a%is only with load eccentricity e%
measured in the direction .,he corresponding strength interaction curve is shown as
case (a) in the threedimensional s&etch in 'ig. 28(d) and is drawn in the plane defined
by the a%es 7n and !ny . *uch a curve can be established by the usual methods for unia%ial
,he situation with respect to strength of bia%ially loaded columns is shown in 'ig. 28.
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et and _ denote the directions of the principal a%es of the cross section. In 'ig. 28(a)
the section is shown sub0ect to bending about the _ a%is only with load eccentricity e%
measured in the direction .,he corresponding strength interaction curve is shown as
case (a) in the threedimensional s&etch in 'ig. 28(d) and is drawn in the plane defined
by the a%es 7n and !ny . *uch a curve can be established by the usual methods for unia%ial
bending. *imilarly 'ig.28(b) shows bending about the a%is only with eccentricity ey
measured in the _ direction. ,he corresponding interaction curve is shown as case (b) in
the plane of 7n and !n% in 'ig. 28(d). 'or case (c) which combines and _ a%is
bending the orientation of the resultant eccentricity is defined by the angle ` T2U
λ=tan− x
=tan− ny
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'ig 28 Interaction diagram for compression plus bia%ial bending
a. unia%ial bending about _ a%is>
b. unia%ial bending about a%is>
c. bia%ial bending about diagonal a%is>
d. Interaction surface.
#ending for this case is about an a%is defined by the angle Ɵ with respect to the a%is.
,he angle ` in 'ig. 28(c) establishes a plane in 'ig. 28(d) passing through the vertical
7n a%is and ma&ing an angle ` with the !n% a%is as shown. In that plane column strength
is defined by the interaction curve labeled case (c). 'or other values of similar curves
are obtained to define a failure surface for a%ial load plus bia%ial bending such as shown
in 'ig. 28(d). ,he surface is e%actly analogous to the interaction curve for a%ial load plusunia%ial bending. ny combination of 7u !u% and !uy falling inside the surface can be
applied safely but any point falling outside the surface would represent failure. Note that
the failure surface can be described either by a set of curves defined by radial planes
passing through the 7n a%is such as shown by case (c) or by a set of curves defined by
hori-ontal plane intersections each for a constant 7n defining load contours.
,he nominal ultimate strength of a section under bia%ial bending and compression is a
function of three variables 7n!n% and !ny which may also be e%pressed as 7n acting at
eccentricities eyL!n%?7n and e%L !ny?7n /ith respect to the and _ a%is.
Constructing such an interaction surface for a given column would appear to be an
obvious e%tension of unia%ial bending analysis. In 'ig. 28(c) for a selected value of Ɵ
successive choices of neutral a%is distance c could be ta&en. 'or each using strain
compatibility and stressstrain relations to establish bar forces and the concrete
compressive resultant then using the e$uilibrium e$uations to find 7n !n% and !ny onecan determine a single point on the interaction surface. Repetitive calculations easily
done by computer then establish sufficient points to define the surface. ,he triangular or
trape-oidal compression -one such as shown in 'ig. 28(c) is a complication and in
general the strain in each reinforcing bar will be different but these features can be
incorporated.
,he main difficulty however is that the neutral a%is will not in general be perpendicular
to the resultant eccentricity drawn from the column center to the load 7n 'or each
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successive choice of neutral a%is there are uni$ue values of 7n !n% and !ny and only for
special cases will the ratio of !n?!n% be such that the eccentricity is perpendicular to the
neutral a%is chosen for the calculation. ,he result is that for successive choices of c for
any given Ɵ the value of ` in 'ig.28(c) and d will vary. 7oints on the failure surface
established in this way will wander up the failure surface for increasing 7n not
representing a plane intersection as shown for case (c) in 'ig. 28(d).
In practice the factored load 7u and the factored moments ! u% and !uy to be resisted are
&nown from the frame analysis of the structure. ,herefore the actual value of
`Larctan(!uy?!u%) is established and one needs only the curve of case (c) 'ig. 8.1Dd to
test the ade$uacy of the trial column. lternatively simple appro%imate methods #resler
load contour method and Reciprocal method are widely used.
3.2.".1 reler load contour method
,he load contour method is based on representing the failure surface of 'ig. 28(d) by a
family of curves corresponding to constant values of 7n. ,he general form of these curves
can be appro%imated by a nondimensional interaction e$uation T2U
M ny 0
¿ =1
M nx
M nx0¿α 1+¿
/here
!n%L7ney>
!n%3L!n%> when !ny L 3.
!nyL7ne%>
!ny3L!ny. /hen !n% L 3.
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,he e%ponentJs X1 and X are e%ponents depending on column dimensions amount and
distribution of steel reinforcement stressstrain characteristics of steel and concrete
amount of concrete cover and si-e of lateral ties or spiral.
3.2.".2 reler reciprocal method
simple appro%imate design method developed by #resler has been satisfactorily
verified by comparison with results of e%tensive tests and accurate calculations It is noted
that the column interaction surface in 'ig. 2G(d) can alternatively be plotted as a
function of the a%ial load 7n and eccentricities e% L!ny?7n and ey L!n%?7n as is shown in
'ig. 2G(a). ,he surface *1 of 'ig. 2G(a) can be transformed into an e$uivalent failure
surface * as shown in 'ig.2G(b) where e% and ey are plotted against 1?7n rather than 7n.,hus e% L ey L 3 corresponds to the inverse of the capacity of the column if it were
concentrically loaded 73 and this is plotted as point C. 'or ey L 3 and any given value of
e% there is a load 7ny3 (corresponding to moment !ny3) that would result in failure. ,he
reciprocal of this load is plotted as point . *imilarly for e% L 3 and any given value of ev
there is a certain load 7n%3 (corresponding to moment !n%3) that would cause failure the
reciprocal of which is point #. ,he values of 7n%3 and 7ny3 are easily established for
&nown eccentricities of loading applied to a given column using the methods already
established for unia%ial bending or using design charts for unia%ial bending.
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'ig 2G Interaction surfaces for the reciprocal load method.
n obli$ue plane *] is defined by the three points # and C. ,his plane is used as an
appro%imation of the actual failure surface *.Note that for any point on the surface *
(for any given combination of e% and e) there is a corresponding plane *. ,hus the
appro%imation of the true failure surface * involves an infinite number of planes *]
determined by particular pairs of values of e% and ey i.e. by particular points # and C.
,he vertical ordinate 1?7ne%act to the true failure surface will always be conservatively
estimated by the distace 1?7nappro% to the obli$ue plane #C (e%tended) because of the
concave upward eggshell shape of the true failure surface. In other words 1?7 nappro% is
always greater than 1?7ne%act .which means that 7nappro% is always less than 7ne%act.
#resler:s reciprocal load e$uation T2U derives from the geometry of the appro%imating
plane. It can be shown that
= + −
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/here
7n L appro%imate value of nominal load in bia%ial bending with eccentricities e % and ey
7nyo L nominal load when only eccentricity e% is present (ey L 3)
7n%o L nominal load when only eccentricity ey is present (e% L 3)
73 L nominal load for concentrically loaded column.
,est result indicate that above e$uation may be inappropriate when small values of a%ial
load are involvef such as when 7n?73 is in the range of 3.3D or less.'or such cases the
member should be desined for fle%ure only.
3.2.3 &ei$n (rocedure
• Short Column !ith mall eccentricitie
1. "stablish the material strength and steel area.
. Compute the factored a%ial load.
2. Compute the re$uired gross column area.
6. "stablish the column dimensions.
4. Compute the load on the concrete area.
D. Compute the load to be carried by the steel.E. Compute the re$uired steel area.
8. esign the lateral reinforcing (ties or spiral).
G. *&etch the design.
Short Column !ith lar$e eccentricitie
1. "stablish the material strength and steel area.
. Compute the factored a%ial load ( Pu) and moment ( Mu).
2. etermine the eccentricity (e).
6. "stimate the re$uired column si-e based on the a%ial load and 13
eccentricity.4. Compute the re$uired gross column area.
D. "stablish the column dimensions.
E. Compute the ratio of eccentricity to column dimension perpendicular to the
bending a%is.
8. Compute the ratio of a factored a%ial load to gross column area.
G. Compute the ratio of distance between centroid of outer rows of bars to
thic&ness of the cross section in the direction of bending.
13. 'ind the re$uired steel area using the CI chart.
11. esign the lateral reinforcing (ties or spiral).
1. *&etch the design.
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3.3 <ootin$
3.3.1 Introduction
,he foundation of a building is the part of a structure that transmits the load to ground to
support the superstructure and it is usually the last element of a building to pass the load
into soil roc& or piles. ,he primary purpose of the footing is to spread the loads into
supporting materials so the footing has to be designed not to be e%ceeded the load
capacity of the soil or foundation bed. ,he footing compresses the soil and causes
settlement. ,he amount of settlement depends on many factors. "%cessive and differential
settlement can damage structural and nonstructural elements. ,herefore it is important to
avoid or reduce differential settlement. ,o reduce differential settlement it is necessary totransmit load of the structure uniformly. +sually footings support vertical loads that
should be applied concentrically for avoid une$ual settlement. lso the depth of footings
is an important factor to decide the capacity of footings. 'ootings must be deep enough to
reach the re$uired soil capacity.
3.3.2 0ype of <ootin$
,he most common types of footing are strip footings under walls and single footings
under columns. Common footings can be categori-ed as follow
1. Individual column footin$ 8<i$ 3-%a9) ,his footing is also called isolated or
single footing. It can be s$uare rectangular or circular of uniform thic&ness
stepped or sloped top. ,his is one of the most economical types of footing. ,he
most common type of individual column footing is s$uare of rectangular with
uniform thic&ness.
. 7all footin$ 8<i$3-%b9) /all footings support structural or nonstructural walls.
,his footing has limited width and a continuous length under the wall.
2. Combined footin$ 8<i$3-%e9) ,hey usually support two or three columns not in a
row and may be either rectangular or trape-oidal in shape depending on column. If
a strap 0oins two isolated footings the footing is called a cantilever footing.
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'ig 213 'ooting types (*piegel 1GG8)
6. at foundation 8<i$3-%f9) !ats are large continuous footings usually placed
under the entire building area to support all columns and walls. !ats are used
when the soilbearing capacity is low column loads are heavy single footings
cannot be used piles are not used or differential settlement must be reduced
through the entire footing system.
4. (ile footin$ 8<i$3-%$9) 7ile footings are thic& pads used to tie a group of piles
together and to support and transmit column loads to the piles.
3.3.3 &ei$n Conideration
'ooting must be designed to carry the column loads and transmit them to the soil safety
while satisfying code limitation. ,he design procedure must ta&e the following strength
re$uirements into consideration
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,he area of the footing based on the allowable bearing soil capacity
,woway shear or punching shear
;neway shear
#ending moment and steel reinforcement re$uired
owel re$uirements
evelopment length of bars
3.3.4 &ei$n (rocedure
Individual column footin$
1. Compute the factored loads.
. ssume the total footing thic&ness.
2. Compute the footing selfweight the weight of earth on top of the footing.
6. Compute the effective allowable soil pressure for superimposed service loads.
4. Compute re$uired footing area.D. Compute the factored soil pressure from superimposed loads.
E. ssume the effective depth for the footing.
8. Chec& the punching shear and beam shear.
G. Compute the design moment at the critical section.
13. Compute the re$uired steel area.
11. Chec& the CI Code minimum reinforcement re$uirement.
1. Chec& the development length.
12. Chec& the concrete bearing strength at the base of the column
3.4 Stair
3.4.1 Introduction
*taircase is an important component of a building providing access to different floors and
roof of the building. It consists of a flight of steps (stairs) and one or more intermediate
landing slabs between the floor levels. ifferent types of staircases can be made by
arranging stairs and landing slabs. *taircase thus is a structure enclosing a stair.
3.4.2 0ype of Staircae
,here are different types of *tairs which depend mainly on the type and function of the
building and on the architectural re$uirements. *ome of the common types of staircases
based on geometrical configurations
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'ig 211 ,ypes of *taircases
(a) *ingle flight staircase ('ig 2E a)
(b) ,wo flight staircase ('ig 2E b)
(c) ;penwell staircase ('ig 2E c)
(d) *piral staircase ('ig 2E d)
(e) Felical staircase ('ig 2E e)
rchitectural considerations involving aesthetics structural feasibility and functional
re$uirements are the ma0or aspects to select a particular type of the staircase. ;ther
influencing parameters of the selection are lighting ventilation comfort accessibility
space etc.
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'ig 21 ,ransversely *upported *tairs
'or purpose of design stairs are classified into two types> transversely and longitudinally
supported.
. ,ransversely supported (transverse to the direction of movement)
,ransversely supported stairs include
a. *imply supported steps supported by two walls or beams or a combination of
both.
b. *teps cantilevering from a wall or a beam.
c. *tairs cantilevering from a central spine beam.
#. ongitudinally supported (in the direction of movement),hese stairs span between supports at the top and bottom of a flight and
unsupported at the sides. ongitudinally supported stairs may be supported in any
of the following manners
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'ig 212 ongitudinally *upported *tairs
a. #eams or walls at the outside edges of the landings.
b. Internal beams at the ends of the flight in addition to beams or walls at the
outside edges of the landings.
c. andings which are supported by beams or walls running in the longitudinal
direction. d. combination of (a) or (b) and (c).
*tairs with $uarter landings associated with openwell stairs.
3.4.3 Component of Stair
,he definitions of some technical terms which are used in connection with design of
stairs are given.
a. 0read or Goin$) hori-ontal upper portion of a step.
b. ,ier) vertical portion of a step.
c. ,ie) vertical distance between two consecutive treads.
d. <li$ht) a series of steps provided between two landings.
e. ;andin$) a hori-ontal slab provided between two flights.
f. 7ait) the least thic&ness of a stair slab.
g. 7inder) radiating or angular tapering steps. h. *offit the bottom surface of a stair
slab.
h. oin$) the intersection of the tread and the riser.
i. >eadroom) the vertical distance from a line connecting the nosings of all treads
and the soffit above.
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'ig. 216 *tairs main Components
3.4.4 &ei$n (rocedure
esign procedure foe single flight *tair
1. 'irst calculate the loads.
. ,hen calculate ma%imum moment.
2. Chec& the depth. If o& then go to ne%t steps otherwise change the section.
6. Calculate reinforcement.4. Chec& for bond and development length.
D. Calculate reinforcement of first flight and spacing.
E. *&etch reinforcement details.
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Chapter 4
,einforced Concrete Structure &ei$ner 8,CS&9
4.1 General
RC* is a computer program for reinforced concrete structure design according to the
CI Code. It includes beam column stair and footing design. Its main purpose is to help
architecture students who do not have enough structural bac&ground but need a structural
calculation to design their building. *o this program is developed with easy to use
interface based on CI Code procedures. RC* provides step by step calculations and is
composed of separate modules for beam stair column and footing design. ,he step by
step design method is considered one of the best methods to help beginning users li&e
civil engineering students. 'or e%ample users do not need to input the all re$uired data at
once. ,he program as&s the minimum re$uired data and provides defaultinput data. ,he
user can use the default data or select other data.
,he modular RC* program structure also has the advantage that each module is
e%ecutable separately and the user can add other modules. RC* is programmed using
!icrosoft @isual *tudio 314. @isual *tudio is much easier to learn than other languages
and provides good graphic user interface (P+I). "ach module is composed of multiple
pages that have been organi-ed using !icrosoft ,abbed Control ialog Component. "ach
module is e%ecuted step by step along the tabs. ,abs are divided into frames for better
organi-ation of different category of input and output data.
RC* is a computer program for reinforced concrete structure design according to the
CI Code. It includes beam column stair and footing design. Its main purpose is to help
architecture students who do not have enough structural bac&ground but need a structural
calculation to design their building. *o this program is developed with easy to use
interface based on CI Code procedures. RC* provides step by step calculations and is
composed of separate modules for beam stair column and footing design. ,he step by
step design method is considered one of the best methods to help beginning users li&e
civil engineering students. 'or e%ample users do not need to input the all re$uired data at
6D
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once. ,he program as&s the minimum re$uired data and provides defaultinput data. ,he
user can use the default data or select other data.
,he modular RC* program structure also has the advantage that each module is
e%ecutable separately and the user can add other modules. RC* is programmed using
!icrosoft @isual *tudio 314. @isual *tudio is much easier to learn than other languages
and provides good graphic user interface (P+I). "ach module is composed of multiple
pages that have been organi-ed using !icrosoft ,abbed Control ialog Component. "ach
module is e%ecuted step by step along the tabs. ,abs are divided into frames for better
organi-ation of different category of input and output data.
4.2 eam odule
4.2.1 Introduction
RC* provides single and double reinforced beam design method in one module in both
/* and +* method.
4.2.2 ,ectan$ular eam &ei$n odule
,he beam design module has IN7+, R"*+, and R"IN';RC"!"N, ",I. ,he
IN7+, tab contain !aterial *trength !oment *hear and imension.
'ig. 6.1 #eam esign !odule
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4.2.3 0 eam &ei$n odule
,he beam design module has IN7+, R"*+, and R"IN';RC"!"N, ",I. ,he
IN7+, tab contain !aterial *trength !oment *hear and imension.
'ig. 6. , #eam esign !odule
4.3 Column odule
4.3.1 Introduction
Column is classified into two types spiral column and tied Column. ,he ,ied Column can
be classified into two types +nia%ial and #ia%ial #ending. ,his program provides all
three types of column design. ,he design of column carrying small eccentricity is
calculated by simple method computed by the CI method for a%ial load with small
eccentricity. If a%ial load is applied with eccentricity the column is sun0ected to moment
and more bending strength.
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4.3.2 Column &ei$n odule
,he column design module has contains three tabs tied column for unia%ial bia%ial
bending and spiral column. ,he tied portion designs for bia%ial bending unia%ial
bending a%ial load. ,he spiral design portion for a%ial load as it is wea& in bending. "ach
design tab contains IN7+, R"*+, and R"IN';RC"!"N, ",I*.
'ig 6.2 Column design module.
4.4 <ootin$ odule
4.4.1 Introduction
,his program provides design module foe individual column footing. ,he thic&ness of the
footing is calculated from twoway and one way shear chec& and the thic&ness is chec&ed
with the bending moment at the face of the column.
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4.4.2 <ootin$ &ei$n module
Individual column footing module has IN7+, ;+,7+, R"IN';RC"!"N, ",I*
tabs. ,he IN7+, tab contains load material column si-e and soil condition based on this
data the program calculates footing si-e and thic&ness to resist shear.
'ig 6.6> 'ooting esign !odule
4." Stair module
4.".1 Introduction
In stair design module some material property and loading data has to input and it gives
the re$uired section for design reinforcement.
4.".2 Stair &ei$n odule
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*tair module has IN7+, ;+,7+, and R"IN';RC"!"N, IPR! tabs. ,he
IN7+, tab re$uires dimension material strength oad. #ased on the input data this
program calculates possible section for reinforcement
'ig. 6.4 *tair esign !odule
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Chaptre-"
Concluion and ,ecommendation
".1 Concluion
,his simplified reinforced concrete structure design program for civil engineering
students based on the merican Concrete Institute Code (CI 218) is e%pected to help
engineering students to design sound concrete structures. ,he ultimate goal of this
program is to assist students in the reinforced concrete structures design and guide them
to design structurally safe buildings. CI Code is the most common code of Reinforce
Concrete structure design but it is difficult to use for beginner users. ,his program will
help engineers in determining the economical si-e and reinforcement re$uirement of a
structural members such as #eam column 'ooting and *tairs within short times per
merican Concrete Institute Code (CI 218). ,he main purpose of this program is to
provide as much basic information to users. RC* does not restrict user to use 0ust one
answer but provides many possibility of structural member design for a set of building
condition. ,hus each calculation was divided into several steps provide typical image for
better understanding popup window is provided to help to get economical section.
".2 ,ecommendation
RC* has four design module #eam (Rectangular ,beam) Column (+nia%ial #ia%ialand spiral) Individual column footing and *tair. ,here has not been enough time to
actually test this program with studentJs actual design and to get feedbac& and add assist
buttons. *everal improvements can be made to this software such as
1. dd ,hree imensional (2) graphical output. !ost students are familiar with
2computer graphics such as utodes& utoC. If this software uses the 2d
graphic output it will be really helpful to students to understand the structure and
connection between structural members.
. dding more design modules would give high degree acceptance such as *lab
(;neway solid slab ,woway slab) *hear wall 7ile foundation !at foundation
wall footing design etc.
2. ifferent types of unit conversions can be added.
6. 7rinting the result with reinforcement details can be added.
4. ,he software can be improve from suitable logic in future.
D. ,he design should be analy-ed repeatedly and thoroughly.
I am hoping that another student will improve this software and develop it to ma&e it an
easier and more useful program.
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,#<#,#C#S
T1U CI Committee 218 #uilding Code Re$uirements for *tructural Concrete and
Commentary CI 21834 and CI 218R34 merican Concrete Indtitution 334.
TU CI Committee 214 etails and etailing of Concrete Reinforcement CI 214GG
(Revised 34) merican Concrete Institute 334.
T2U Nilson rthur F. arwin avid and olan Charles /. esign of Concrete
*tructures 16th "dition !cPrawFill Companies Inc. New _or& 33G.
T6U *implified esign of Reinforced Concrete2rd "dition by Fenry 7ar&er.
T4U 7hil ! 'ergution <Reinforced Concrete 'undamentals= 'ourth edition Vohn /iley 5
*ons Inc. 1G82.
TDU Vac& C. !cCormac 5 Russell F. #rown <esign of Reinforced Concrete= Ninth
"dition Vohn /iley 5 *ons Inc. 316.
TEU /inter+r$uhrat ; Rour&eNilson <esign of Concrete *tructures= *eventh "dition
!cPrawFill Companies Inc. New _or&.
T8U Computer ided esign of @arious *tructural !embers +sing @isual *tudio 313 by
!. ,RI+ I*! Roll No 3G331 epartment of Civil "ngineering R+",316.
TGU Reinforced Concrete *tructure esign ssistant ,ool for #eginners developed by
angyu Choi for the faculty of the *chool of rchitecture +niversity of *outhern
California 33
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@@Tension one area
s0 6 7max < $ < d;
a 6 's0< !y( @ '.E> < !c0 < $(;
M0 6 '.? < s0 < !y < 'd .> < a((;
M/ 6 'M<0/( M0;
@@ copression *one
s/ 6 'M/ @ '.? < !y < 'd /.>(((;
s3 6 s0 B s/;
l$lesult.Text 6 HTension one ein!orcement rea'sqin(6H B s3.ToString'( B
HInH B H:um$er o! Main$ar&H B Mat-.ound's3 @ a$(.ToString'( B
HInH B H Compression one ein!orcement rea'sqin(&H B s/.ToString'( B HInH B
H:um$er o! Main$ar&H B Mat-.ound's/ @ a$(.ToString'(;
txts0.Text 6 Mat-.ound's3 @ a$(.ToString'( B HJH B $n.ToString'(;
txts/.Text 6 Mat-.ound's/ @ a$(.ToString'( B HJH B $n.ToString'(;
txtd0.Text 6 d.ToString'( B HinH;
D3
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txt$0.Text 6 $.ToString'( B HinH;
txts0.Text 6 Mat-.ound's(.ToString'(BHinH;
+
+
+
+
, #eam esign
+* !ethod
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace ein!orce"Concrete"Structure"Design
#
pu$lic partial class T"%eam"WSD & Form
#
pu$lic T"%eam"WSD'(
D1
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#
)nitiali*eComponent'(;
+
dou$le !c0, !y, $, -, M, $n,!c3,!y/, -!, $w, p, n,d, 2,!s,!c,s0,s,p0,p/,*,1d,!c/,Mc,s/,a$;
pri4ate 4oid $tnesult"Clic2'o$1ect sender, 54entrgs e(
#
!c3 6 dou$le.7arse'txtCS.Text(;
!y/ 6 dou$le.7arse'txt8S.Text(;
$ 6 dou$le.7arse'txtFW.Text(;
- 6 dou$le.7arse'txt%9.Text(;
M 6 dou$le.7arse'txtM.Text(;
$n 6 dou$le.7arse'txt%:.Text(;
$w 6 dou$le.7arse'txtWW.Text(;
-! 6 dou$le.7arse'txtFT.Text(;
!y 6 0 < !y/;
!c0 6 0 < !c3;
!c 6 .=> < !c0;
!s 6 .= < !y;
d6 - /.>;
n 6 /? @ '>A < Mat-.Sqrt'!c0((;
s0 6 'M<0/( @ '!s<'d.><-!((;
p 6 s @ '$ < d(;
a$ 6 '3.0=0 < '$n @ E( < '$n @ E(( @ =;
p0 6 p < n;
2 6 ''p0 B .> < '-! @ d( < '-! < d(( @ 'p0 B -! @ d((;
p/ 6 2 < d;
i!'p/-!(
#
D
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picture%ox0.isi$le 6 true;
Message%ox.S-ow'HT %eam is ensuredH(;
* 6 '3 < 2 < d / < -!( @ '/ < 2 < d -!(;
1d 6 d *;
s/ 6 'M<0/( @ '!s < 1d(;
!c/ 6 'M<0/( @ '''/ < 2 < d -!( @ '/ < 2 < d(( < $ < -! < 1d(;
i!'!c/!c(
#
group%ox0.isi$le 6 true;
Mc 6 !c/ < '''/ < 2 < d -!( @ '/ < 2 < d(( < $ < -! < 1d(;
s 6 'Mc( @ '/ < !s < 1d(;
l$lesult.Text 6 HSteel rea 'Sqin(6H B s.ToString'( B HInH B
H:um$er o! main ein!orcement6H B Mat-.ound''s @ a$((;
txts.Text 6 Mat-.ound's @ a$(.ToString'( B HJH B $n.ToString'(;
txtd0.Text 6 d.ToString'( B HinH;
txt$.Text 6 $.ToString'( B HinH;
txt-!.Text 6 -!.ToString'( B HinH;
txt$w.Text 6 $w.ToString'( B HinH;
+
else
#
group%ox0.isi$le 6 true;
s 6 s/;
l$lesult.Text 6 HSteel rea 'Sqin(6H B s.ToString'( B HInH B
H:um$er o! main ein!orcement6H B Mat-.ound''s @ a$((;
txts.Text 6 Mat-.ound's @ a$(.ToString'( B HJH B $n.ToString'(;
txtd0.Text 6 d.ToString'( B HinH;
D2
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txt$.Text 6 $.ToString'( B HinH;
txt-!.Text 6 -!.ToString'( B HinH;
txt$w.Text 6 $w.ToString'( B HinH;
+
+
else
#
Message%ox.S-ow'HT%eam is :QT 5:S5D ,%eam is act as a etangular %eamH(;
s 6 s0;
l$lesult.Text 6 HSteel rea 'Sqin(6H B s.ToString'( B HInH B
H:um$er o! main ein!orcement6H B Mat-.ound''s @ a$((;
group%ox/.isi$le 6 true;
txts/.Text 6 Mat-.ound's @ a$(.ToString'( B HJH B $n.ToString'(;
txtd/.Text 6 d.ToString'( B HinH;
txt$0.Text 6 $w.ToString'( B HinH;
+
+
+
+
, #eam esign
+* !ethod
D6
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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace ein!orce"Concrete"Structure"Design
#
pu$lic partial class T"%eam"Design"SD & Form
#
pu$lic T"%eam"Design"SD'(
#
)nitiali*eComponent'(;
+
dou$le !c0, !y, $, d, M, $n, a$, $w,!y/,!c/, -!,a,a/,s,s0,s!,M!,Mw,a3,a=,a>;
dou$leNO a0 6 new dou$leN/O;
dou$leNO sw 6 new dou$leN/O;
pri4ate 4oid $tnesult"Clic2'o$1ect sender, 54entrgs e(
#
!c/ 6 dou$le.7arse'txtCS.Text(;
!y/ 6 dou$le.7arse'txt8S.Text(;
$ 6 dou$le.7arse'txtFW.Text(;
d 6 dou$le.7arse'txtD.Text(;
D4
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M 6 dou$le.7arse'txtM.Text(;
$n 6 dou$le.7arse'txt%:.Text(;
$w 6 dou$le.7arse'txtWW.Text(;
-! 6 dou$le.7arse'txtFT.Text(;
a$ 6 '3.0=0 < '$n @ E( < '$n @ E(( @ =;
!c0 6 0 < !c/;
!y 6 0 < !y/;
a= 6 -!;
s0 6 'M<0/( @ '.? < !y < 'd .> < a=((;
a> 6 's0 < !y( @ '.E> < !c0 < $(;
@@ Flenge rea and Moment
s! 6 '.E> < '!c0 @ !y( < '$ $w( < -!(;
M! 6 .? < s! < !y < 'd .> < -!(;
@@We$Rs ein!orcement rea
Mw 6 M < 0/ M!;
i! 'a> -!( @@ T %eam 5nsure
#
group%ox0.isi$le 6 true;
a 6 3;
!or 'int i 6 0; i K6 =; iBB(
#
swNiO 6 'Mw( @ '.? < !y < 'd 'a @ /(((;
a0NiO 6 'swNiO < !y( @ '.E> < !c0 < $w(;
a/ 6 a0NiO;
a3 6 a/ a;
i! 'a3 K6 ./>(
#
s 6 swNiO B s!;
DD
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l$lesult.Text 6 Hein!orcement rea'sqin(6H B 's(.ToString'( B HInH B
H:um$er o! ein!orcement6H B Mat-.ound's @ a$(.ToString'(;
txts.Text 6 Mat-.ound's @ a$(.ToString'( B HJH B $n.ToString'(;
txtd0.Text 6 d.ToString'( B HinH;
txt$.Text 6 $.ToString'( B HinH;
txt-!.Text 6 -!.ToString'( B HinH;
txt$w.Text 6 $w.ToString'( B HinH;
$rea2;
+
a 6 a/;
+
+
else i! 'a> K -!(
#
Message%ox.S-ow'HT-e %eam will act as a 5CT:GL %eamH(;
group%ox/.isi$le 6 true;
a 6 3;
!or 'int i 6 0; i K6 =; iBB(
#
swNiO 6 'Mw( @ '.? < !y < 'd 'a @ /(((;
a0NiO 6 'swNiO < !y( @ '.E> < !c0 < $(;
a/ 6 a0NiO;
a3 6 a/ a;
i! 'a3 K6 ./>(
#
l$lesult.Text6 Hein!orcement rea'sqin(6H B 'swNiO( B HInH B
H:um$er o! ein!orcement6H B Mat-.ound'swNiO @ a$(;
txts/.Text 6 Mat-.ound'swNiO @ a$(.ToString'( B HJH B $n.ToString'(;
DE
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txtd/.Text 6 d.ToString'( B HinH;
txt$0.Text 6 $w.ToString'( B HinH;
$rea2;
+
a 6 a/;
+
+
+
+
+
,ied Column
+* !ethod
using System;
using System.Collections.Generic;
D8
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using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace ein!orce"Concrete"Structure"Design
#
pu$lic partial class Tied"Column"niaxial & Form
#
pu$lic Tied"Column"niaxial'(
#
)nitiali*eComponent'(;
+
dou$le !c0, dl, ll, !y, $, -, d, pg, pu, g,M, -0, a, c, c0, !s, st, s0,Mo, 7$, M$, Md, $n, a$;
pri4ate 4oid $tnSu$mit"Clic2'o$1ect sender, 54entrgs e(
#
!c0 6 dou$le.7arse'txtCS.Text(;
!y 6 dou$le.7arse'txt8S.Text(;
dl 6 dou$le.7arse'txtDL.Text(;
ll 6 dou$le.7arse'txtLL.Text(;
M 6 dou$le.7arse'txtM.Text(;
$ 6 dou$le.7arse'txtC9.Text(;
- 6 dou$le.7arse'txtCS.Text(;
pg 6 dou$le.7arse'txtCS.Text(;
$n 6 dou$le.7arse'txt%:.Text(;
a$ 6 '3.0=0 < '$n @ E( < '$n @ E((;
DG
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pu 6 0./ < dl B 0. < ll;
g 6 pu @ '.E> < .A < '.E> < !c0 B .0 < pg < !y((;
-0 6 g @ $;
i! '- -0(
#
@@5ecti4e dept- o! Column d
d 6 - /;
a 6 pu @ '.E> < !c0 < $(;
c 6 a @ .E>;
c0 6 .3 @ '.3 B !y @ /?(;
@@%alanced !ailure condition !s6!y ,s06st@/
st 6 'pg < g( @ 0;
!s 6 !y;
s0 6 st @ /;
7$ 6 '.E> < !c0 < a < $( 's0 < !s( B 's0 < !y(;
M$ 6 7$ < .> < '- a( B s0 < !s < '.> < - /.>( B s0 < 'd - @ /(;
@@ o4erturning moment
Mo 6 .= < s0 < !y < d;
@@ Design Moment
Md 6 '''pu < 'M$ Mo(( @ 7$( B Mo(<0/;
i!'Md K M(
#
l$lesult.Text 6 HSteel area 'sqin(6H B st.ToString'( B HInH B H:um$er o! $ar&H BMat-.ound'st @ a$(.ToString'(;
+
else
#
Message%ox.S-ow'H7lease C-ange T-e S5CT)Q:H(;
E3
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+
+
else
#
Message%ox.S-ow'Hplease C-ange t-e section o! t-e columnH(;
+
+
+
+
,ied Column #ia%ial
+* !ethod
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace ein!orce"Concrete"Structure"Design
E1
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#
pu$lic partial class Tied"Column"%iaxial & Form
#
pu$lic Tied"Column"%iaxial'(
#
)nitiali*eComponent'(;
+
dou$le 7, Mx, My, $,!c0,!y, -, ex, ey, m, 7o,px,py, $n, a$, s,st, Fa, F$, n, c0, c/, )x, )y,Sutx, Suty, 7n, pg;
pri4ate 4oid $tnSu$mit"Clic2'o$1ect sender, 54entrgs e(
#
!c0 6 dou$le.7arse'txtCS.Text(;
!y 6 dou$le.7arse'txt8S.Text(;
7 6 dou$le.7arse'txtTL.Text(;
Mx 6 dou$le.7arse'txtMx.Text(;
My 6 dou$le.7arse'txtMy.Text(;
$ 6 dou$le.7arse'txtCW.Text(;
- 6 dou$le.7arse'txtC9.Text(;
$n 6 dou$le.7arse'txt%:.Text(;
pg 6 dou$le.7arse'txtpg.Text(;
a$ 6 '3.0=0 < '$n @ E( < '$n @ E((;
@@ eciprocal Met-od
ex 6 'Mx < 0/ @ 7(;
ey 6 'My < 0/ @ 7(;
m 6 !y @ '.E> < !c0(;
7o 6 '.3= < '0 B .0 < pg < m( < !c0 < $ < -(@0;
@@ Condition !a@FaB!$@F$60
Fa 6 .3= < !c0 < '0 B .0 < pg < m(;
E
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F$ 6 .=> < !c0;
s 6 .0 < pg < $ < -;
n 6 Mat-.ound''/? < 0( @ '>A < Mat-.Sqrt'!c0(((;
)x 6 $ < - < - < - @ 0/ B / < s < '/ < n 0( < '- @ / /.>( < '- @ / /.>(;
)y6 - < $ < $ < $ @ 0/ B / < s < '/ < n 0( < '$ @ / /.>( < '$ @ / /.>(;
c0 6 - @ /;
c/ 6 $ @ /;
Sutx 6 )x @ c0;
Suty 6 )y @ c/;
px 6 ''0 Mx < 0/ @ Sutx( < $ < - < Fa( @ 0;
py 6 ''0 My < 0/ @ Suty( < $ < - < Fa( @ 0;
@@ %resler 5quation
7n 6 '0 @ '0 @ px B 0 @ py 0 @ 7o((<0;
i! '7n7(
#
st 6 .0 < pg < $ < -;
l$lesult.Text 6 Hein!orcement area 'sqin(6H B st.ToString'( B HInH B HDesignLoad'2ip(6H B 7n.ToString'( B HInH B
H:um$er o! %ar&H B Mat-.ound'st @ a$(.ToString'(;
group%ox0.isi$le 6 true;
txts.Text6 Mat-.ound'st @ a$(.ToString'(BHJHB$n.ToString'(;
txt$.Text 6 $.ToString'( B Hinc-H;
txt-.Text 6 -.ToString'( B Hinc-H;
+
else
#
Message%ox.S-ow'HDesign is:QT QP, 7lease c-ange t-e sectionH(;
+
E2
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+
+
+
*piral Column
+* !ethod
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace ein!orce"Concrete"Structure"Design
#
pu$lic partial class Spiral"Column"Design"SD & Form
#
pu$lic Spiral"Column"Design"SD'(
#
)nitiali*eComponent'(;
+
dou$le !c, !y, Dl, Ll, 7g, g, D, D0, g0, 7c, 7s, s, $n$, a$, dc, 7s0, 7s/, s, 7u, c;
E6
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pri4ate 4oid $tnesult"Clic2'o$1ect sender, 54entrgs e(
#
!c 6 dou$le.7arse'txtCS.Text(;
!y 6 dou$le.7arse'txt8S.Text(;
Dl 6 dou$le.7arse'txtDL.Text(;
Ll 6 dou$le.7arse'txtLL.Text(;
7g 6 dou$le.7arse'txtS.Text(;
$n$ 6 dou$le.7arse'txt%:.Text(;
a$ 6 '.AE>= < '$n$ @ E( < '$n$ @ E((;
7u 6 '0./ < Dl B 0. < Ll(;
g 6 '7u( @ '.A < .E> < '.E> < !c < '0 .0 < 7g( B .0 < 7g < !y((;
D 6 Mat-.Sqrt''= < g( @ 3.0=0(;
D0 6 Mat-.ound'D(;
g0 6 '3.0=0 < D0 < D0( @ =;
@@ Load carried $y comrete 7c
7c 6 .A < .E> < .E> < g0 < '0 7g < .0( < !c;
@@ load carried $y steel 7s
7s 6 7u 7c;
@@ Steel rea s
s 6 7s @ '.E> < .A < !y(;
@@ assuming co4er 0.>RR
dc 6 D0 / < 0.>;
c 6 '3.0=0 < dc < dc( @ =;
7s0 6 .=> < !c < ''g0 @ c( 0( @ !y;
s 6 '= < .00( @ '7s0 < dc(;
7s/ 6 ''= < a$( @ 'dc < s((;
E4
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l$lesult.Text 6 H Diameter o! column 'inc-(&6H B D0.ToString'( B HInH B Hein!orcementrea 'Sqin(,s 6H B s.ToString'( B
HInH B Hno o! $ar6H B Mat-.ound's @ a$(.ToString'(BHInHBHse J3 spiral steelinc@c6HB Mat-.ound's(.ToString'(;
+
+
+
'ooting esign
+* !ethod
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace ein!orce"Concrete"Structure"Design
ED
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#
pu$lic partial class Design"Square"Footing & Form
#
pu$lic Design"Square"Footing'(
#
)nitiali*eComponent'(;
+
dou$le !c0, !y, W, D, dl, ll,M, a, q, qu, $, c,a3,$3,c3,smin,s0,x3,x=, d, $0, x0,p,s,
x/, , 0, s, -, L, L0,n, $n, a$, m, u, c;
pri4ate 4oid $tnesult"Clic2'o$1ect sender, 54entrgs e(
#
!c0 6 dou$le.7arse'txtCS.Text(;
!y 6 dou$le.7arse'txt8S.Text(;
W 6 dou$le.7arse'txtSW.Text(;
D 6 dou$le.7arse'txtDF.Text(;
dl 6 dou$le.7arse'txtDL.Text(;
ll 6 dou$le.7arse'txtLL.Text(;
$n 6 dou$le.7arse'txt%:.Text(;
$0 6 dou$le.7arse'txtCW.Text(;
q 6 dou$le.7arse'txtS7.Text(;
a$ 6 '3.0=0 < '$n @ E( < '$n @ E(( @ =;
0 6 'dl B ll( @ 'q W < .0 < D(;
L0 6 Mat-.Sqrt'0(;
@@lengt-U Widt-
L 6 Mat-.Ceiling'L0</(@/;
6 L < L;
qu 6 ''0./ < dl B 0. < ll(( @ ; @@ 2s!
EE
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@@punc-ing S-ear
@@For equili$rium u6c
@@ u6<qu''$0Bd(@0/(<'$0<d(@0/((<qu
@@c6=<.?<Mat-.Sqrt'!c0(<'=<'$0Bd(<d(
@@ Critical Dept- d calculation
m 6 '0 < .A> < Mat-.Sqrt'!c0( < 0==( @ qu;
a 6 m B 0;
$ 6 $0 < m B / < $0;
c 6 '0== < B $0 < $0(;
p 6 $ < $ = < a < c;
@@ quadratic equation is a second order o! polynomial equation in a single 4aria$le
@@ x 6 N $ B@ sqrt'$V/ =ac( O @ /a
i! 'p (
#
x0 6 '$ B System.Mat-.Sqrt'p(( @ '/ < a(;
x/ 6 '$ System.Mat-.Sqrt'p(( @ '/ < a(;
i! 'x0 K UU x/(
#
d 6 x0 <'0(;
+
else i! 'x/ K UU x0(
#
d 6 x/ <'0(;
+
+
@@ %eam S-ear C-ec2
u 6 'L @ / $0 @ /= d @ 0/( < L < qu;
c 6 / < .A> < Mat-.Sqrt'!c0( < d < L < 0/;
E8
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i! 'c u(
#
@@ Moment Calculation
M 6 .> < 'L < qu < '.> < L $0 @ /=((; @@ 2!t
@@ein!orcement rea calculation
n 6 !y @ '.E> < !c0 < L < 0/(;
a3 6 .> < n;
$3 6 d;
c3 6 'M<0/( @ '.? < !y(;
s 6 $3 < $3 = < a3 < c3;
i! 's (
#
x3 6 '$3 B System.Mat-.Sqrt's(( @ '/ < a3(;
x= 6 '$3 System.Mat-.Sqrt's(( @ '/ < a3(;
i! 'x3 K x= UU x3 (
#
s0 6 x3;
+
else i! 'x= K x3 UU x= (
#
s0 6 x=;
+
+
smin 6 './ @ !y( < L < 0/ < d; @@ inc-
i! 'smin s0(
#
s 6 smin;
EG
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+
else
#
s 6 s0;
+
@@ T-ic2ness o! t-e !ooting
- 6 d B 0.> < '$n @ E( B 3 B .>;
l$lesult.Text 6 HLengt- Q! Footing,L'!t(6H B L.ToString'( B HInH B HWidt- o! Footing6H BL.ToString'( B HInH B Hein!orcement rea'sqin(6H B 's(.ToString'( B HInH B
HT-ic2ness Q! Footing'in(6H B Mat-.ound'-(.ToString'( B HInH B H:o o! %ar6H B
Mat-.ound''s( @ a$(.ToString'(;
group%ox0.isi$le 6 true;
txtL.Text 6 L.ToString'(BHinH;
txtL0.Text 6 L.ToString'(BHinH;
txt-.Text 6 Mat-.ound'-(.ToString'(BHinH;
txts.Text 6 Mat-.ound''s( @ a$(.ToString'(B HJHB$n.ToString'(;
txts0.Text 6 Mat-.ound''s( @ a$(.ToString'( B HJH B $n.ToString'(;
+
else
#
Message%ox.S-ow'HS-ear C-ec2 is :ot QPH(;
+
+
+
+
83
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*tair esign
/* !ethod
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Windows.Forms.Design;
namespace ein!orce"Concrete"Structure"Design
#
pu$lic partial class Stair"Design"WSD & Form
#
pu$lic Stair"Design"WSD'(
#
)nitiali*eComponent'(;
+
dou$le !c0, !y, t, T, , nt, s, st, s, s0, 5, max, d, all, $n, w, ww, Mmax, LL, DL, n, 0,2, 1, $a, !c, !s, r,
w/, wt, wl, l0, r0, a, L, , de, d0, l/, r/, wr, d0, all0;
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pri4ate 4oid $tnesult"Clic2'o$1ect sender, 54entrgs e(
#
!y 6 dou$le.7arse'txt8S.Text(;
!c0 6 dou$le.7arse'txtCS.Text(;
t 6 dou$le.7arse'txtWT.Text(;
T 6 dou$le.7arse'txtTW.Text(;
6 dou$le.7arse'txtW.Text(;
LL 6 dou$le.7arse'txtLL.Text(;
DL 6 dou$le.7arse'txtDL.Text(;
$n 6 dou$le.7arse'txt%:.Text(;
l/ 6 dou$le.7arse'txtLeL.Text(;
r/ 6 dou$le.7arse'txtL.Text(;
nt 6 dou$le.7arse'txt:T.Text(;
$a 6 .AE>= < '$n @ E( < '$n @ E(;
!c 6 .=> < !c0;
!s 6 .= < !y;
n 6 '/? @ '>A < 'Mat-.Sqrt'!c0((((;
r 6 '!s @ !c(;
2 6 n @ 'n B r(;
1 6 0 '2 @ 3(;
0 6 .> < !c < 1 < 2;
l0 6 '> @ 0/( B l/;
r0 6 '> @ 0/( B r/;
@@ total Lengt-
L 6 l0 B r0 B 'nt < T( @ 0/;
@@total ig-t
6 'nt < T( @ 0/;
@@ load calculation
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ww 6 't @ 0/( < 0>;
@@load !or step portion
w 6 ww < 'Mat-.Sqrt'T < T B < (( @ T;
@@wt o! ange
w/ 6 .> < ' @ 0/( < 0>;
wt 6 w B w/ B LL B DL B 00./>;
@@wt on landing
wl 6 ww B 00./> B LL;
wr 6 00./> B LL;
@@Moment calculation
a 6 'wl < l0 < 'l0 @ /( B wr < r0 < 'r0 @ / B ' B l0(( B wt < < 'l0 B @ /(( @ L;
Mmax 6 a < L @ / wl < l0 < 'L @ / l0 @ /( wt < 'L @ / l0( < .> < 'L @ / l0(;
d0 6 Mat-.Sqrt'Mmax @ 0(;
de 6 t '3 @ =( < .><'$n @ E(;
i! 'de d0(
#
Message%ox.S-ow'HDept- C-ec2 is o2H(;
+
else
#
Message%ox.S-ow'HDept- C-ec2 is not o2H(;
+
@@ein!orcement calculation
s 6 'Mmax < 0/( @ '!s < 1 < de(;
s 6 Mat-.ound''$a < 0/( @ s(;
@@distri$ution ein!orcement
st 6 .0E < 0/ < t;
s0 6 Mat-.ound''.00 < 0/( @ st(;
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5 6 '3.0=0 < $n < 0/( @ '$n @ E(;
@@S-ear C-ec2
max 6 a;
d 6 max @ '5 < 1 < de(;
all 6 3.= < Mat-.Sqrt'!c0( @ '$n @ E(;
i! 'all d(
#
Message%ox.S-ow'HS-ear c-ec2 is o2H(;
+
else
#
Message%ox.S-ow'HS-ear c-ec2 is not Q2H(;
+
@@ %ond c-ec2
d0 6 a @ '0/ < de(;
all0 6 00 < Mat-.Sqrt'!c0(;
i! 'all0 d0(
#
Message%ox.S-ow'H%ond c-ec2 is o2H(;
+
else
#
Message%ox.S-ow'H%ond c-ec2 is not o2H(;
+
picture%ox0.isi$le 6 true;
group%ox0.isi$le 6 true;
txtM.isi$le 6 true;
txtM/.isi$le 6 true;
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txtD.isi$le 6 true;
txtD/.isi$le 6 true;
l$lesult.ext 6 HMain ein!orcement rea'Sqin(6H B s.ToString'( B HInH B
H:um$er o! rein!orcement 6H B Mat-.ound's@ $a(.ToString'( B HInH B HDistri$utionrein!orcement rea'Sqin(6H B st.ToString'( B
HInH B H:um$er o! rein!orcement 6H B Mat-.ound'st @ $a(.ToString'(;
txtM.Text 6 s.ToString'(;
txtM/.Text 6 s.ToString'(;
txtD.Text 6 st.ToString'(;
txtD/.Text 6 st.ToString'(;
+
+
+