This document provides disclosure of an Indian public safety standard for composite construction published by the Bureau of Indian Standards. It aims to promote transparency and access to information for citizens, particularly disadvantaged communities and those pursuing education.
The attached standard, IS 3935 (1966): Code of Practice for Composite Construction, provides guidance on the design and construction of composite structures made of prefabricated structural units like steel beams, precast reinforced or prestressed concrete beams, and cast-in-situ concrete. It seeks to obtain monolithic action between prefabricated and cast components to improve structural efficiency. The document introduces the standard and provides its scope, terminology, symbols, material requirements, and general design considerations for composite members.
Analysis and Design of Reinforced Concrete Solid Slab Bridgeijtsrd
Structural planning and analysis is an art and science of designing with economy, elegance and sturdiness. Structural designing requires an in depth structural analysis on which the planning is predicted, to compete within the ever competitive market, The use of software can save many man hours and efforts in structural analysis and an effort was made in the present study to achieve this objective. The purpose of this study is to analyze and design the solid deck slab bridge by STAAD Pro and manual method under different loading conditions. And also the analysis results in term of shear, bending moment, axial force and deflection were checked by STAAD Pro which is passes through many different load combinations. The maximum design moments resulting from the combinations of various loading cases.part 1 The study deals with the planning and analysis of Solid Deck Slab using Staad Pro software. In this study solid deck slab having 8.2 m long span and the thickness of slab 0.65 m and the slab is simply supported. The drafting and detailing work was completed using AutoCAD software and thereafter the entire design work was completed using “Staad Pro v8i ss6. Pooja Kumre | Abhay Kumar Jha | Barun Kumar "Analysis and Design of Reinforced Concrete Solid Slab Bridge" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-6 , October 2021, URL: https://www.ijtsrd.com/papers/ijtsrd47524.pdf Paper URL : https://www.ijtsrd.com/engineering/civil-engineering/47524/analysis-and-design-of-reinforced-concrete-solid-slab-bridge/pooja-kumre
Analysis and Design of Reinforced Concrete Solid Slab Bridgeijtsrd
Structural planning and analysis is an art and science of designing with economy, elegance and sturdiness. Structural designing requires an in depth structural analysis on which the planning is predicted, to compete within the ever competitive market, The use of software can save many man hours and efforts in structural analysis and an effort was made in the present study to achieve this objective. The purpose of this study is to analyze and design the solid deck slab bridge by STAAD Pro and manual method under different loading conditions. And also the analysis results in term of shear, bending moment, axial force and deflection were checked by STAAD Pro which is passes through many different load combinations. The maximum design moments resulting from the combinations of various loading cases.part 1 The study deals with the planning and analysis of Solid Deck Slab using Staad Pro software. In this study solid deck slab having 8.2 m long span and the thickness of slab 0.65 m and the slab is simply supported. The drafting and detailing work was completed using AutoCAD software and thereafter the entire design work was completed using “Staad Pro v8i ss6. Pooja Kumre | Abhay Kumar Jha | Barun Kumar "Analysis and Design of Reinforced Concrete Solid Slab Bridge" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-6 , October 2021, URL: https://www.ijtsrd.com/papers/ijtsrd47524.pdf Paper URL : https://www.ijtsrd.com/engineering/civil-engineering/47524/analysis-and-design-of-reinforced-concrete-solid-slab-bridge/pooja-kumre
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KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
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as sensible heat due to lowering the flue gas exit temperature.
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condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
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Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
Every time when lecturers/professors need to conduct examinations they have to sit down think about the questions and then create a whole new set of questions for each and every exam. In some cases the professor may want to give an open book online exam that is the student can take the exam any time anywhere, but the student might have to answer the questions in a limited time period. The professor may want to change the sequence of questions for every student. The problem that a student has is whenever a date for the exam is declared the student has to take it and there is no way he can take it at some other time. This project will create an interface for the examiner to create and store questions in a repository. It will also create an interface for the student to take examinations at his convenience and the questions and/or exams may be timed. Thereby creating an application which can be used by examiners and examinee’s simultaneously.
Examination System is very useful for Teachers/Professors. As in the teaching profession, you are responsible for writing question papers. In the conventional method, you write the question paper on paper, keep question papers separate from answers and all this information you have to keep in a locker to avoid unauthorized access. Using the Examination System you can create a question paper and everything will be written to a single exam file in encrypted format. You can set the General and Administrator password to avoid unauthorized access to your question paper. Every time you start the examination, the program shuffles all the questions and selects them randomly from the database, which reduces the chances of memorizing the questions.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
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We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
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An Approach to Detecting Writing Styles Based on Clustering Techniquesambekarshweta25
An Approach to Detecting Writing Styles Based on Clustering Techniques
Authors:
-Devkinandan Jagtap
-Shweta Ambekar
-Harshit Singh
-Nakul Sharma (Assistant Professor)
Institution:
VIIT Pune, India
Abstract:
This paper proposes a system to differentiate between human-generated and AI-generated texts using stylometric analysis. The system analyzes text files and classifies writing styles by employing various clustering algorithms, such as k-means, k-means++, hierarchical, and DBSCAN. The effectiveness of these algorithms is measured using silhouette scores. The system successfully identifies distinct writing styles within documents, demonstrating its potential for plagiarism detection.
Introduction:
Stylometry, the study of linguistic and structural features in texts, is used for tasks like plagiarism detection, genre separation, and author verification. This paper leverages stylometric analysis to identify different writing styles and improve plagiarism detection methods.
Methodology:
The system includes data collection, preprocessing, feature extraction, dimensional reduction, machine learning models for clustering, and performance comparison using silhouette scores. Feature extraction focuses on lexical features, vocabulary richness, and readability scores. The study uses a small dataset of texts from various authors and employs algorithms like k-means, k-means++, hierarchical clustering, and DBSCAN for clustering.
Results:
Experiments show that the system effectively identifies writing styles, with silhouette scores indicating reasonable to strong clustering when k=2. As the number of clusters increases, the silhouette scores decrease, indicating a drop in accuracy. K-means and k-means++ perform similarly, while hierarchical clustering is less optimized.
Conclusion and Future Work:
The system works well for distinguishing writing styles with two clusters but becomes less accurate as the number of clusters increases. Future research could focus on adding more parameters and optimizing the methodology to improve accuracy with higher cluster values. This system can enhance existing plagiarism detection tools, especially in academic settings.
1. Disclosure to Promote the Right To Information
Whereas the Parliament of India has set out to provide a practical regime of right to
information for citizens to secure access to information under the control of public authorities,
in order to promote transparency and accountability in the working of every public authority,
and whereas the attached publication of the Bureau of Indian Standards is of particular interest
to the public, particularly disadvantaged communities and those engaged in the pursuit of
education and knowledge, the attached public safety standard is made available to promote the
timely dissemination of this information in an accurate manner to the public.
इंटरनेट मानक
“!ान $ एक न' भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
“Invent a New India Using Knowledge”
“प0रा1 को छोड न' 5 तरफ”
Jawaharlal Nehru
“Step Out From the Old to the New”
“जान1 का अ+धकार, जी1 का अ+धकार”
Mazdoor Kisan Shakti Sangathan
“The Right to Information, The Right to Live”
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
“Invent a New India Using Knowledge”
है”
ह”
ह
IS 3935 (1966): Code of practice for composite construction
[CED 38: Special Structures]
2.
3.
4. IS : 3936 - 1986
Indian Standard
CODE OF PRACTICE FOR
COMPOSITE CONSTRUCTION
(Fifth Reprint MAY 1993)
UDC 693.55 : 693.814
0 Copyright 1967
BUREAU OF JNDJAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
Gr 7 April 1967
( Reaffirmed 2003 )
5. IS : 3935 : 1966
Indian Standard
CODE OF PRACTICE FOR
COMPOSITE CONSTRUCTION
Composite Construction Sectional Committee, BDC 32
Chairman Rcpmnling
SIIRI K. F. ANTIA M. N. Dastur and Co Private Ltd, Calcutta
Members
COL A. C. AOA Engineer-in-Chief’s Branch, Army Headquarters
SHRI M. P. APT& S. B. Joshi & Co Ltd, Bombay’
SHRI A. P. BACCIII Sahu Cement Service, NW Delhi
SHRIMATI SHAUUNTAI.A BHAQAT
DR S. M. K. CHETTY
Indian Institute of Technology! Bombay
Central Building Research Instttute (CSIR), Roorkee
SHRI S. Ii. CHOKXAVATIA Engineering Construction Corporation Ltd, Bombay
SHRI N. K. BALACIIANDRAN ( Alternate)
SIXRI S. P. DAS Braithwaite Burn & Jessop Construction Co Ltd,
Calcutta
SHRI P. ,J. JANUS The Concrete Association of India, Bombay
SHRI Y. K. MEIITA ( Alternate)
JOINT DIRECTOR STAHDARDS Research, Designs & Standards Organization ( Minis-
( BUILDINQ& STRUCTURES) try of Railways )
DEPUTY DIRECTOR STAND-
ARDS ( BUILDING& STRUC-
TURES) ( /Illem& )
SHRI G. C. MATHUR National Buildings Otganization ( Ministry of Works
SIIRI 0. N. MATHUR ( A&ra&~
& Housing )
SHRI Y. K. MURTHY Central Water & Power Commission ( Ministry of
Irrigation & Power )
SHRI B. T. A. SACAR ( Alternnk )
SHRI C. M. PATRL Bihar Prestressing Private Ltd, Bhagalpur
SHRI N. N. PURANDARE Institution of Engineers ( India), Calcutta
SHRI J. DURAI RAJ Hindustan Housing Factory Ltd, New Delhi
SHRI K. G. SALVI ( Alkrnde )
SHRI B. BALWANT RAO Roads Wing, Ministry of Transport
SHRI G. VENEATESULU ( Alkwzate )
SJIRI T. N. SUIHIARAO Gammon India Ltd, Bombay
SI~RI N. V. HISGORASI (.llfernate )
SURVY:YORop 1$‘oRxs V Central Public Works Department
SIIRI B. S. KRISHNAMACHAB, Director General, ISI ( Ex-o&o Member)
Deputy Director General
Secretary
SHRI Y. R. TANEJA
Deputy Director ( Civ Engg), ISI
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
7. IS : 3935 - 1966
Indian Standard
CODE OF PRACTICE FOR
COMPOSITE CONSTRUCTION
0. FOREWORD
0.1 This Indian Standard was adopted by the Indian Standards Institution
on 23 November 1966, after the draft finalized by the Composite Construc-
tion Sectional Committee had been approved by the Civil Engineering
Division Council.
0.2 Though composite construction is not a very new technique, its import-
ance in structural construction is of recent realization in this country. With
the advancement in the manufacture of structural units, composite construc-
tion has assumed great importance. This technique essentially consists in pro-
viding the required monolithic action between the prefabricated units, such
as steel beams, precast reinforced or prestressed concrete beams and cast-
in-situ concrete and thereby increasing the structural efficiency of the whole
section. Prefabricated construction and cast-in-situ construction have
their own advantages and disadvantages; and composite construction seeks
to combine the advantages and minimize the disadvantages of these methods
of construction. For example, in the conventional type of steel beam
and slab construction, each beam carries the entire load transmitted
to it by the slab, ‘but if sufficient st ar connection is provided between the
beam and the slab, they will act together as a composite section to carry the
load and their action will be similar to that of a tee beam. For a given
condition, considerably more variation in depth of the section is possible
with composite construction than with the conventional construction.
Composite construction has also the advantages that the prefabricated units
can act as formwork for in-situ concrete and the units requiring to be trans-
Ported and erected are lighter than those in case,of fully precast and prefabri-
cated construction. In this code, it is attempted to provide a general guid-
ance to designers and field engineers for the design and construction of
composite structures. This code may be applied to both dynamically and
statically loaded structures.
0.2.1 Basically there are two methods of assembly in composite construc-
tion, namely, (a) the unproped method, wherein the prefabricated units
are made sufficiently strong to carry the dead weight of wet concrete and
constructional live load together with any incidental formwork which may
be required; and (b) the proped method, wherein the prefabricated units
are supported during the laying and curing of in-situ concrete so that when
,
3
8. IS : 3935 - 1966
the props are removed the whole of the section is monolithic and carries
the total dead weight of the concrete as well as live load.
0.3 The provisions of this code apply mainly to the composite beams for
buildings and bridges made up of prefabricated structural units and cast-
in-situ concrete. Whilst the common methods of design and construction
have been covered in this code, special systems of destgn and construction
of composite beams not covered by this code may be permitted on production
of satisfactory evidence regardin
tests or both.
g their adequacy and safety by analysis or
0.4 All requirements of IS : 456-1964*, IS : 1343-196Ot and IS : 800-1962f.
in so far as they apply, shall be deemed to form part of this code except
where otherwise laid down in this code.
0.5 In this code it has been assumed that the design of composite construc-
tion work is entrusted to a qualified engineer and that the execution of the
work is carried out under the direction of an experienced supervisor.
0.6 For the purpose of deciding whether a particular requirement of this
standard is complied with, the final value, observed or calculated, expressing
the result of a test or analysis, shall be rounded off in accordance with
IS : 2-1960s. The number of significant places retained in the rounded
off value should be the same as that of the specified value in this standard.
1. SCOPE
1.1 This standard deals with the design and construction of composite
structures made up of prefabricated structural units and cast-in-situ
concrete. The prefabricated units may consist of steel members or pre-
stressed or reinforced concrete precast members.
2. TERMINOLOGY
2.0 For the purpose of this standard, the following definitions shall apply.
2.1 Castellations -Protrusions or recesses on the top surface of the
prefabricated concrete units to provide the necessary monolithic action
between the cast-in-situ concrete and prefabricated units.
2.2 Composite Members - Structural members comprising prcfabri-
cated structural units of steel, prestressed concrete, or reinforced concrete
and cast-in-situ concrete connected together in such a manner that they
act monolithically.
*Code of practice for plain and reinforced concrete ( second recision ).
tCode of practice for prestressed concrete.
$Code of practice for use of structural steel in general building construction ( rcJiscd ).
§Rules for rounding off numerical values ( wised),
4
9. IS : 3935 - 1966
2.3 Shear Connectors - Structural elements, such as anchors, studs,
channels and spirals, intended to transmit the horizontal shear between the
prefabricated member and the cast-G-situ concrete and also to prevent
vertical preparation at the inter-face
3. SYMBOLS
3.1 For the purpose of this standard and unless otherwise defined in the
text, the following symbols shall have the meanings indicated against each:
b = width of the steel flange of the rigid connector at surface of contact
d = the diameter of the stud connector in cm
h = maximum thickness of the flange of a channel connector in cm
measured at the face of the web
H = height of the stud connector in cm
I = moment of inertia of the transformed composite section
L = length of the channel shear connector in cm
m, = the statical moment of the transformed area on the slab side of
the contact surface about the neutral axis of the composite section
or the statical moment of area of reinforcement embedded in the
concrete slab for negative moment
q = permissible shear stress measured as inclined tension in concrete
Q = the safe shear resistance in kg of one shear connector or one pitch
of a spiral shear connector
S,, = the horizonta1 shear per linear cm at the plane of contact of the
in-situ concrete slab and the prefabricated beam at the cross-
section of the composite beam under consideration
t = thickness of the web of a channel shear connector in cm
V = the total external ( vertical ) shear due to the superimposed load
acting on the composite section
0eu= crushing strength of 150 mm concrete cube at 28 days
ost = permissible tensile stress in the anchor bar
4. MATERIALS
4.1 Concrete - In-situ concrete and concrete for plain and reinforced
concrete prefabricated structural units shall conform to the requirements
of IS : 456-1964*.
4.1.1 Concrete for prestressed concrete structural units shall conform to
the requirements of IS : 1343-1960t.
*Code of practice for plain and reinforced concrete ( second
rruision),
tCode_of practice for prestressed concrete.
5
10. IS : 3935 - 1966
4.2 Steel
4.2.1 Structural &xl - Structural steel shall comply with IS : 226-1962*,
IS: 961-19621_, IS: 2062-19621, or Designation St 440 of IS: 1977-19625,
whichever is appropriate.
4.2.2 Shear Connectors- Steel for shear connectors shall comply with
IS : 226-1962*, IS : 432 ( Part I )-19667, IS : 961-1962t, Designation St 440
of IS : 1977-19629, or IS : 2062-1962$, whichever is appropriate.
4.2.3 Steel for Rivets, Bolts and Nuts, and Washers - Steel for rivets, bolts
and nuts, and washers shall conform to IS : 800-196211.
4.2.4 Steel for
Calzcrele Reinforcement - The steel reinforcement for rein-
forced concrctc shall conform to IS : 432 ( Part I )-19667, IS : 432 ( Part
II )-1966**, IS : 1139-1966tt, IS : 1786-1966$$, or IS : 1566-1960& which-
ever is appropriate.
4.2.5 Prestressiq Steel - The prestressing steel for prestressed concrete
structural units shall comply with IS : 1785 ( Part I )-1966Tjy!, or IS : 2090-
19621/11,whichever is appropriate.
5. GENERAL DESIGN CONSIDERATIONS
5.1 Basic Requirements - The general provisions related to the design
and construction of plain and reinforced concrete, prestressed concrete and
steel structures as laid down in IS : 456-1964***, IS : 1343-1960tti, and
IS : 800-1962jj, respectively shall apply together with the additional require-
ments specified herein for composite sections.
__~--~ __~~
*Specification for structural steel ( standard quality) ( ~llirrl revision).
tSpeciGcation for structural steel ( high tensile) ( reuired ).
$Spccification for structural sterl ( fusion welding quality ).
$Specification for structural steel (ordinary quality ).
~[Specilicarion for mild steel and mediuti tensile steel bars and hard-drawn steel wire for
concrete reinforcrment: Part I Mild steel and medium tensile steel bars ( secondrevision ).
l/Code of practice for use of structural steel in general building construction ( revised ).
**Specification for mild steel and medium tensile steel bars and hard drawn steel wire
for concrete reinforcement: Part II Hard drawn steel wire (second revision).
ttSpccification for hot rolled mild steel- and medium ;ensile steel deformed bars for
concrete remforcement ( revised ).
ffspecification for cold twisted steel bars for concrete reinforcement (reuised ).
s§Specification for hard drawn &eel wire fabric for concrete reinforcement.
T[RSpecification for plain hard drawn steel wire for prestressed concrete: Part I ColG
drawn stress relieved wire ( revised ).
(JIjSpeciiication for high tensile steel bars used in prestressed concrete,
***Code of practide for plain and reinforced concrete ( second revision).
tttCode of practice for prestressed concrete.
6
11. IS : 3935 - 1966
5.1.1 In any composite structure provisions shall be made for all conditions
of stresses that may occur in accordance with principles of mechanics,
recognized methods of design and sound engineering practice. Before
taking up the detailed design, the engineer-in-charge should satisfy himself
on the correct estimation of all loads and on the adequate static equilibrium
of the structure, particularly, in regard to safety against overturning of over-
hanging members. The anchorages or counterweights provided for
overhanging members ( during construction and service ) should be such
that static equilibrium should remain even when the overturning moment
is doubled.
5.2 Composite Action - For the purpose of design, if the prefabricated
unit is adequately supported before placing of the in-situ concrete, it shall be
designed to sustain self-load only. If the load of the formwork, constructional
live load and the in-situ concrete is carried directly by the prefabricated unit
without adequate props, this additional load shall also be accounted for in
addition to self-load. The composite section shall be designed for all the
loads imposed on the member taking note of the fact that the composite
action of the member is effective only for the loads imposed after the compo-
site action has started to function.
5.2.1 In prescribing the requirements of this code, full composite action
has been assumed between the prefabricated member and the ix-situ
concrete. For such full composite action to be considered effective, the
in-situ concrete shall have attained at least 75 percent of the designed 2%day
strength of 15 cm cubes.
5.2.2 The composite section should preferably be proportioned in such a
way that the neutral axis of the composite section is generally located below
the in-situ concrete slab.
If the neutral axis is located inside the in-situ concrete slab, the
portion of the slab below the neutral axis shall not be considered effective
for computing moments of inertia or resisting moments except for deflection
calculations.
5.3 Equivalent Section - For prefabricated units in prestressed concrete
or reinforced concrete, consideration shall be given to the different moduli
of elasticity of the concrete of the precast and of the in-situ portions.
For prefabricated units in steel, the effective gross area of concrete
slab shall be converted into the corresponding equivalent area of steel.
This shall be done by dividing the effective area of the concrete slab by the
modular ratio.
5.4 Modulus of Elasticity - The values of moduli of elasticity of steel
and concrete shall be taken in accordance with requirements of the relevant
Indian Standard codes. The modular ratio shall be also calculated on the.
7
12. IS : 3935 - 1966
basis of these moduli of elasticity except where otherwise laid down in the
relevant design codes, such as in IS : 456-1964*.
5.4.1 The modular ratio between precast concrete and cast-&situ
concrete shall be determined on the basis of values of moduli of elasticity for
the two concretes.
5.5 Loads
5.5.1 Dead Loads-Dead loads shall be calculated on the basis of the
unit weights taken in accordance with IS : 191 l-1961f. In all calculations
of loading, unless otherwise established or specified, the weight of reinforced
and prestressed concrete shall be taken as 2 400 kg/m3 and that of plain
concrete as 2 300 kg/ma.
5.5.2 Live Loads, Snow Loads and Wind Loads - In general building cons-
truction, live loads, snow loads and wind loads shall be assumed in accordance
with IS : 875-1964$,. In the case of structures of other types, live loads,
wind loads, snow loads and other loads shall be taken as specified by the
appropriate authority.
5.5.3 Eurt/zquake Loads-Effect of earthquake loads shall be taken in
accordance with IS : 1893-1966s.
5.6 Permissible Stresses
5.6.1 Permissible Stresses iu Concrete
5.6.1.1 For reinforced cowete members - The permissible stresses shall
be in accordance with the requirements of IS : 456-1964*.
5.6.1.2 For prestressed concrete members - The permissible stresses shall
be in accordance with the requirements of IS : 1343-19607.
5.6.2 Permissible Stresses in Steel Reinforcement
5.6.2.1 For reinforced cowrete members - The permissible stresses shall be
in accordance with the requirements of IS : 456-1964*.
5.6.2.2 For prestressed concrete members - The permissible stresses in steel
shall be in accordance with the requirements of IS : 1343-19601/.
5.6.3 Permissible Stresses in Structural Steel - The permissible stresses in
structural steel members shall be in accordance with the requirements
of IS : 800-19621/.
*Code of practice for plain and reinforced concrete ( second rehion ).
tschedule of unit weights of building materials.
fCode of practice for structural safety of buildings: Loading standards ( rc&d ).
§Recommendations for earthquake resistant design of structures ( revised).
fCode of practice for prestressed concrete.
l]Code of practice for use of structural steel in general building construction ( revised).
8
13. IS : 3935 - 1966
5.7 Differential Shrinkage and Creep of Concrete-The effects of
shrinkage and creep of the cast-in-situ concrete on the prefabricated
member shall be considered. It shall be ensured that the stresses in the
prefabricated member do not exceed the permissible stresses by more than
25 percent when-these effects are superimposed on the stresses caused by the
worst combination of other loads.
5.8 Deflection
5.8.1 Live Loud Deflections-Live load deflections shall be calculated
on the basis of the moment of inertia of the transformed composite section
using the full value of the moduli of elasticity of the concretes.
5.8.2 Dead Load Dejections
5.8.2.1 For beams shored during construction, the dead load deflections
shall be calculated on the basis of the moment of inertia of the transformed
composite section using one-half the value of moduli of elasticity of concretes.
5.8.2.2 For beams not shored during construction, the dead load
deflections shall be calculated on the basis of the moment of inertia of the
prefabricated beam alone except that deflections due to dead loads applied
after the concrete slab has attained 75 percent of the specified 2%day strength
shall be calculated according to 5.8.2.1.
5.8.2.3 Steps, such as giving a reverse camber to compensate for the
full dead load plus half the live load deflections shall be taken in design and
construction in order to prevent excessive:
a) dishing of the slabs and beams built with shores,
b) thickening of slabs and beams built without shores, and
c) deflection of beams in service.
5.8.3 Limiting Deflections-For simply supported beams the total deffection
due to dead load, live load and impact should preferably not exceed l/600
of the span, or the deflection due to live load and impact should preferably
not exceed l/800 of the span. The deflection of cantilever arms due to
dead load, live load and impact shall not. exceed I /300 of the cantilever
arms and due to live load and impact shall not exceed l/400 of the cantilever
arm.
5.9 Design of Slabs
5.9.1 In continuous spans, the effective span of slab shall be:
a) central distance between the outstand of supporting flanges of the
steel prefabricated units ( see Fig. 1 ) ; and
b) clear distance between the webs of precast reinforced concrete or
prestressed concrete units, reduced by two-thirds of the total
thickness of the slab and flange of the precast unit at the face of
the web ( see Fig. 2 ).
9
14. IS : 3935 - 1966
- EFFECTIVE SPAN
- -
FIG. 1 EFFECTIVE SPAN OF SLAB SUPPORTED ON STEEL
PREFABRICATED UNITS
5.9.2 The slabs shall be designed in accordance with requirements of
IS : 456-1964*. In the design of slabs the stress caused by composite
action need not be added to the bending stresses in the slabs.
5.10 Flange Width of Composite Beams
5.10.1 Beams Having Flanges on Bofh Sides - The width of flange ( slab )
eonsidered effective in the design of the composite tee beam except in the
case of edge beam shall not exceed the least of the following:
a) One-fourth the span length of the beam;
b) Distance, centre-to-centre, of the beam; and
c) The web ( or rib ) thickness plus twelve times the least thickness
of the slab plus, in the case of slabs resting on wide flange
( see Fig. 2 ), two-thirds the total thickness of slab and the flange of
the prefabricated unit at the face of the web ( or rib ).
5.10.2 For Edge Beams-The effective flange ( slab ) width for inner
and outer parts ( measured from the centre line of the beam ) to be taken
in the case of an edge beam shall not .exceed least of the following:
a) One-twelfth the span of the beam ( for both the inside and the
outside parts ) ;
b) Half the distance to the adjoining beam ( for the inside part ) and
the actual width ( for the outside part ) ; and
c) Six times the least thickness of the slab plus half the web ( or rib )
thickness plus, in the case of slabs resting on wide flanges ( see
Fig. 2), one-third the total thickness of the slab and the flange, at the
face of the web ( or rib ) ( for both the inside’and the out$de parts ).
5.10.3 Allowance
if
or Openings -Any permanent openings which exist
shall be deducted rom the calculated width of the flange ( slab ) at the
section under consideration. The loss of section due to the openings may,
however, be compensated by other suitable provisions, such as trimmer
b~~ti, in which case the full flange width shall be taken into account.
.wi ‘ofpractice for plain and reinforced concrete ( sucond
n&im ) .
10
15. IS I 3935 - 1966
I
+ EFFECTIVE SPAN-
OF SLAB
I
FIG. 2 EFFECTIVE SPAN OF SLAB SUPPORTED ON PRECAST
CONCRETE UNITS
6. PREFABRICATED STEEL AND IN-SITU CONCRETE
COMPOSITE MEMBERS
6.1 Steel Structural Members - The steel structural members may be
of rolled steel joists or any.other built-up sections. The structural members
shall preferably be symmetrical about the vertical axis. The top flanges
and web plates shall be able to absorb and transmit the forces from the
connectors. The minimum thickness of the free overhang shall not be less
than one-tenth of the free overhang ( see Fig. 3 ) so that heavy distortion at
the junction with the connectors does not occur.
FIG. 3 MINIMUM FLANGE THICKNESS FOR STEEL PREFABRICATED .UNITJ
11
16. IS : 3935 - 1966
6.2 With steel prefabricated units, the depth of the steel section should
preferably be not less than 1/30th of the span and the depth of the composite
section should be not less than 1/25th of the span. If-depths smaller than
these are used, the sections should be adequate to limit deflections to the
values obtained with the limiting ,depths specified above.
6.3 Slab and Haunch
6.3.1 7’1~ minimum thickness of the concrete above the steel structural
memljer shall bc not less than 100 mm and, therefore, haunches should
necessarily bc provided where thinner slabs are used. The slope of the
haunches shall not bc greater than one vertical to three horizontal for slabs
thinner than 100 mm.
6.3.2 The depth of the haunch shall be chosen so that the depth of the
composite structural member is not greater than one and a half times the
depth of the steel structural member and further the depth of the haunch
shall not be greater than one and a half times the thickness of the slab.
6.3.3 Where a supporting fillet is provided between the prefabricated
steel section and the concrete slab, its section shall be ignored in computing
the total composite section.
6.4 Shear Connectors
6.4.1 In case of connections between in-situconcrete and the prefabricated
steel unit, resistance to horizontal shear shall be provided by mechanical
shear connectors at the junction of the concrete slab and the steel beam or
girder. The connectors shall be capable of resisting the shear force between
the slab and the structural steel member and at the same time prevent the
vertical separation of the slab from the structural steel member at the inner
face ( see 6.4.2 ). The shear connectors shall be of the type which permit a
thorough compaction of concrete in order to ensure that their entire surfaces
are in contact with concrete.
6.4.1.1 The shear connectors shall be of weldable steel and shall be end
welded to the structural members. The capacity of the welds at permissible
stress shall be not less than the shear resistance of the connectors. Welding
shall be in accordance with the requirements of the relevant Indian Standard.
NOTE - In the case of studs, specialized fusion welding will bc necessary and hence
expert advice and necessary equipment should be available. To permit satisfactory
welding of studs, the gap between the heads of two adjacent connectors should not be
less than 15 mm.
6.4.1.2 Studs and channel shear connectors shall not be spaced further
apart than 600 mm. The clear distance between the edge of the beam
flange and edge of the connectors shall not be less than 25 mm. The
concrete cover over the shear connectors in all directions shall not be less
than 25 mm.
12
17. IS : 3935 - 1966
6.4.1.3 To ensure that the concrete slab is adequately tied down to the
steel flange, the overall height of the shear connector ( that is, the length of
stud, diameter of the helix, height of the channel, hoop, etc ) should not be
less than 50 mm nor project less than 25 mm into the compression zone of
the concrete slab. The thickness of the compression zone sha_ll be that at
the section of maximum bending moment.
6.4.2 Shear connectors shall consist of any or a combination of the
following types:
4 Rigid connectors consisting of short lengths of bars, angles or
tees welded on to the flange of the steel fabricated units ( see Fig. 4 ).
These connectors derive their resistance to horizontal shear from
the bearing pressure of the concrete. Failure or slip is generally
associated with the crushing of concrete. Some suitable means
( anchors ) capable of preventing the separation of the in-situ
concrete from the prefabricated units in the direction perpendicular
to the contact surface should be introduced with these connectors.
b) Flexible connectors, such as studs ( see Fig. 5 ) and channels
( see Fig. 6 ) welded to the contact surface of the prefabricated
unit. These derive their resistance essentially through the bending
of the connectors.
c) Bond or anchorage connectors consisting of ( see Fig. 7 ):
1) mild steel bars welded to the flange of the prefabricated unit
in the form of vertical or inclined loop.stirrups, or
2) inclined bars with one end welded to the flange of the steel
unit and the other end suitably bent, or
3) bar stirrups welded to the flange of the steel unit at each loop.
These derive their resistance through bond and/or anchorage
action.
d) Any other mechanical device to resist horizontal shear and to
prevent vertical separation of in-situ concrete from prefabricated
unit.
6.4.3 Connectors, such as channels, tees and angles, more closely spaced
with smaller faces are preferable to those with larger faces and widely placed,
since the former arrangement induces a uniform distribution of shear stress
in the concrete. The spacing of the connectors shall not exceed three times
the thickness of the slab. Connectors should be as stiff as possible so that
an even distribution of stress on the surface is achieved. Channels and tees
should be preferred to angles. Welding seams should be taken around the
connectors as continuous welds.
13
18. IS : 3935 - 1966
k!!!!Y
H e
4A Typlcal Rigid Connectors
L FILLET WELD
I I
/-
BARS THREADED THROUGH
HOLES IN TEE CONNECTORS
, , T
48 Typical Bar Rigid Connector 4C Typical Rigid Tee Connector with
Anchorage Device to Hold Down the
Concrete Slab Against Uplift (Concrete
.not Shown )
FIG. 4 TYPICAL RIGID CONNECTORS
6.5 Design Requirements of Shear Connectors
6.5.1 The connection between the steel prefabricated unit and the in-situ
concrete slab shall be checked for integral action of the composite structure
at all loads so that:
a) shear along the contact surface is transferred without slip, and
b) separation of the prefabricated unit and the in-situ slab in a direc-
tion perpendicular to the slab is prevented.
14
19. 25mm
jw +i
P
-+
P
tli3
+
t
MIN
Depth of head < O-667 o where
d It the stud diameter Q: 16 mm
5A With Head
t--td
I
1
I
JL
!I t’
-A-
I 1
Hooks should be rotated against Area of weld < twice
the direction of horizontal shear sectional area of steel
that is towards the centre of or weldsize, t’=0*365 d
simply supported beams
56 Hook Type SC Weld Detail
tf
..
w
19
FIG:~ TYPICAL STUD SHEAR CONNECTORS z
I
s
g:
20. Is : 3935 - 1966
CHANNELS
FIG. 6 TYPICAL FLEXIBLE CHANNEL CONNECTOR
6.5.2 Horizontal Shear Force - The horizontal shear to be transferred by
the shear connectors, that is, horizontal shear at the plane of contact of the
prefabricated and in-situ unit shall be computed from the equations:
+_!+
NOTE 1- For beams erected without temporary props the total external shear V is
the total external shear from live load and impact plus any shear from the dead load
added after the concrete has attained a strength compatible to the composite action
assumed’ ( see 5.2 ). For beams provided with properly designed props during construc-
tion, V is the external shear from dead load, live load and prop removal loads.
NOTE 2- The compressive concrete area is transformed into an equivalent area of
steel by dividing the effective concrete area with the modular ratio m.
6.5.3 When negative moments are to be resisted by the prefabricated
section alone, shear connection between the prefabricated section and the
slab need not be provided in the regions of negative bending moments.
6.5.4 When negative moments are to be resisted by the composite section,
shear connection should be provided throughout the full length of the beam,
but the concrete on the tension side of the neutral axis shall not be taken as
effective except as a device to develop the full stress in the reinforcing steel
embedded in.
16
21. CONCRETE NO
SPACING of CONNECTING ANCHORS WHEN EMPLOYED ALONE ENDS BENT AND WELDED
ENDS WELDED WITHOUT A BEND
7A Typical Bond Type Connectors
ENDS FORGED FLAT
22. E
..
CONCRETE NOT SHOWN CONCRETE -NOT SHOWN
78 Typical Composite Dowel and Anchor
Connectors
FIG. 7 TYPICAL BOND OR AXCHORACE CONNECTORS
licz
P
SPIRALS
7C Typic+1 Spiral
Connector
. i ‘-.;
23. IS : 3935 : 1966
6.5.5 Shear IZesistance OJ ~onneclors - Shear resistance values of any
connector devices may be calculated by a rational method after duly taking
into account the stress conditions, the permissible bearing pressure of concrete,
the permissible bond stress in concrete, the structural properties in the steel
used for the connectors and the strength of the weld. The design require-
ments for dilrerent types of shear connectors are given in 6.5.6 to 6.5.9.
6.5.6 Higid ~omeclors --The safe shear resistance capacity of a rigid
connector is given by the equation:
Q= I;lJ Ab
where
I3 = the permissible bearing pressure WI c’oncrctc fijund I)y the
cxprcssion:
0.25 crc,,
3 A
d-----
A&-, this value being limited to 0.6 Go,,
A = the area to which the bearing force is transmitted, that is
n’ b’ c’ d’, being equal to the product of width of the top
flange of steel unit at surface of contact and the depth of
concrete slab including the haunch ( see Fig. 8 ),
Ah = tlic bearing area ofthe coimrctor, that is arca of tile trans-
rnitting fact of tlic C0J111WtOl‘, say a b c d I .rec Fig. %).
6.5.6.1 The spacing and size of the rigid connectors shall satisfy the
following requirements:
The bearing pressure on the face of the connector should not
exceed the permissible value Q.
The longitudinal shear stress along the shearing surface between
two successive connectors should not be greater than two and a
half times the permissible shear stress for concrete. This condition
shall he deemed to he satisfied if 2.5 bq = S,,.
The projected area along a slope of 1 to 5 from one rigid connector
on to another should be at least three times the area of the face
of the connector ( see Fig. 9 ).
6.5.6.2 The following precautions are necessary with rigid connectors:
Angular or wedge shaped placing of the connectors will tend to
split the concrete slab and shall, therefore, be prohibited.
The area of the bearing face of the connector shall not be less than
one-fifth of the area to which the bearing force is transmitted.
As far as possible, rigid connectors shall be associated with anchors
( see Fig. 4B and 4C ) so that shear is resisted partly by bond
of the concrete and partly by the bearing pressure of the concrete
against the face of the rigid connectors.
19
24. IS : 3935 - 1966
/
t10133NN03
319NV Cll9ltl
I
I i
I
,J ,q
FIG. 8
FIO. 9 RULE FOR DETERMINING
THE MINIMUM
SPACINGOF RIGID
CONNECTORS
20
25. IS : 3935 - 1966
6.5.7 Anchor Connector - Anchor connectors are either used alone or are
used in conjunction with rigid connectors. The safe shear resistance of an
anchor connector is given by the following equation:
where
At = cross-sectional area of the anchor bar, and
X = coefficient having following values:
Anchors with bond length of not less than 40
times the ‘diameter of the bar including the
hook in the compression zone of the concrete
Looped anchors with diameter of loop greater
than 15 times the diameter of bar
Looped anchor usually used in combination
with rigid connectors with diameter of loop
less than 15 times the diameter of the bar
Hooked anchors usually used in. combination
with rigid connectors where the ends of the
straight anchors are hooked but the bond
length in the compression zone of the concrete
is less than 40 times the diameter of the bar
Value of K
1.0
l-0
0.7
0.5
The above equation for shear resistance of the anchor bar is indepen-
, dent of the angle of inclination of the bar. But anchors may generally be
either vertical or inclined at about 45”.
’ 6.5.7.1 Spacing of anchors when used alone shall not be less than 0.7
times the depth of the slab and shall not be greater than two times the dqpth
of slab.
6.5.7.2 Spacing of anchors when, associated with rigid connectors
shall not be greater than two aud a half times the depth of slab. The mini-
mum spacing of Anchors associated with rigid connectors shall be governed
by the design conditions of rigid connectors.
6.5.7.3 The anchors may be welded to the beam or the ends bent over
and well placed completely around. The anchors shall be brought up to
the top surface of the flange, then bent over and ends hooked. The bond
length should be adequatein accordance with the provisions of IS : 456-1964*
with further provision that the portiorl from the upper bend to the hook is
at least ten times the diameter of the bar.
*Code of practice for plain and reinforced concrete (second revkim ).
21
26. IS I 3935 - 1966
6.5.8 Flexible Connectors
6.5.8.1 Welded stud connector - The safe shear resistance or welded
connectors ( see Fig. 5 ) with minimum stud head diameter of d + 12 mm
and stud head height of 12 mm, and of steel with minimum ultimate strength
of 4 600 kg/cma, yield point of 3 500 cm2 and an elongation of 20 percent
is given by the following equation:
kg/
a) For a ratio of H/d less than 4.2:
Q= 4.8 Hdx&kg
b) For a ratio of H/d equal to or greater than 4.2:
Q= 19.6 d” 1/c kg
6.5.8.2 Channel jexible connector - For channel connectors made of
steel with minimum ultimate strength of 4 200 to 5 000 kg/cm2, yield point
of 2 300 kg/ems and an’elongation of 21 percent, the safe shear resistance
is given by the equation ( see Fig. 6 ):
Q= 10.7 ( h + O-5 t ) L l/d, kg
NOTE - Flange shall be oriented’ against the direction of horizontal shear, that is,
towards the centre, in case of simply supported beams.’
6.5.8.3 Spiral connectors ( see Fig. 7C ) - For spiral connectors, the
shear resistance shall be given by the equation:
Q= 315 d +Ku kg
where
Q = the safe shear resistance in kg of one pitch of a spiral bar,
and
d = the diameter of the round bar used in spiral connectors
in cm.
The diameter of the spiral bars shall preferably be between 12 and
20 mm, smaller diameter bars may be used but care shall be exercised in
welding as the welding heat is likely to impair the ductility of small bars.
In all composite beams the spirals shall extend at least half way in the slab.
The ratio of the pitch of the spiral to the diameter shall be between 0.5
and 4.0. The developed length of the spiral per pitch shall not be less than
20 times the diameter of the bar. From fabrication consideration, the spiral
pitch shall be within the limits of 100 mm and 1100 mm.
6.5.9 S’uing of Connectors -The aggregate capacity of all connectors
located at a transverse section of a beam shall be equal to the horizontal
shear divided by the pitch. Thus the required pitch or spacing parallel to
22
27. the beam axis of the connectors may be determined by the equation:
Is : 3935 - 1966
where
P = spacing or pitch of connectors in the direction of the axis,
and
Jv = number of connectors at one transverse section -of beam.
6.5.10 End Shear Connectors-At each end of a simply supported girder
in composite construction in steel and concrete, an end connector shall
be provided to counteract the eflects of temperature, shrinkage and creep in
addition to the external shear forces. The shear resistance of such an end
connector shall have the following values unless otherwise determined by
rational analysis:
Shear resistance of each end connector =
M ma
I
where
Al = maximum b.ending moment on the composite beam due
to additional loads operating after the composite action
has been effected.
6.5.10.1 The end shear connector shall consist of mechanical device
having adequate shear resistance as calculated in 6.5.10. Such mechanical
device may consist of cut piece of rolled steel with the bearing face directed
towards the centre of the beam or it may consist of anchor bars spreading
out into the slab away from the ccntrc of the beam ( see Fig. 10 and 11 ).
7. PREFABRICATED PRESTRESSED OR REINFORCED
CONCRETE AND IN-SITU CONCRETE COMPOSITE MEMBERS
7.1 Composite structures in which the in-situ concrete is assumed to act
integrally with the precast beam shall be inter-connected to transfer the
horizontal shear along the contact surfaces and to prevent the vertical
separation of these units. Transfer of shear shall be by shear bars, castella-
tions and by bond. The units shall further be tied together by the extension
of web reinforcement.
7.1.1 Ties - Separation of the component elements in the direction per-
pendicular to the contact surface shall be prevented by ties adequately
embedded on each side of the contact surface; The spacing of such ties shall
not exceed four times the thickness of the slab or 60 cm whichever is less. The
minimum cross-sectional area of the ties, in each metrc of the span shall
not be less than 0.15 percent of the contact area or 130 sq mm. All web
reinforcement of the prefabricated unit shall be extended into the cast-
in-situ concrete.
23
28. I I ,
CONCRETE NOT SHOWN
FIG. 10 TYPICAL END CONNECTORWITH ANCHORINGROD
In the case of either dynamically or statically loaded structures where
the horizontal shear at the inter-face at ultimate load is less than -$- it is
not necessary _toprovide vertical ties.
7.2 Bond Strength at the Inter-face -The bond strength at the inter-face
shall be checked for ultimate load. The inter-face shall always be made
rough for effective bonding.
7.2.1 The ultimate values of the horizontal shear stress ,at the inter-face
shall be calculated by using the formula given in 6.5.2. If the calculated
shear stresses are more than the values given under no slip condition in
Table 1 for strength of the &z-situconcrete, it shall be taken that the slip
24
29. IS : 3935 - 1966
IN-SIT;L;;NCRETE
/
Y
L STEEL BEAM
FIG. 11 ALTERNATIVE ARRANGEMENT OF END CONNECTORS,
SHOWING ANCHORING RODS IN OPPOSITE DIRECTION
has occurred. The design shall then be made taking a frictional shear
resistance of 10 kg/cm2 and the balance stress to, be resisted by steel shear
connectors stressed to a maximum of 1 340 kgjcm2. The inter-face shear
shall not, however, exceed the value given under the maximum permissible
shear stress in Table 1.
TABLE 1 PERMISSIBLE SHEAR STRESS IN THE INTER-FACE AT
ULTIMATE LOAD
( All valuesin kg/cm*. )
150 mm CuBH:
STRENGTH
OF IN-SITu
CONCRETE AT
28 DAYS
PERMISSIBLE PERMISSIBLE
SHEAR SHEAR
AT NO SLIP ATSLIP
MAXIBfUY
PERMEI~IBLE
INTEB-~AcE
SHEAR
(1) (2) (31 (4)
150
200 12 10 14
2501
3001
350 ) 14 10 20
400J
25
30. IS : 3935 - 1966
7.3 Shear Bars - The shear bars at the ends of the girders to a length
of one-half to three-fourth depth of the girder shall be spaced closer and
designed to take full shear force under ultimate conditions.
7.4 Castellation - Castellations may be provided as a means of
transferring horizontal shear. Whilst generally the rectangular type of
castellation is recommended, it is important to ensure that whatever type of
castellation is adopted, it has been successfully tried out. The castellations
should be so designed that they are capable of resisting the horizontal shear
in accordance with the requirements of IS : 456-1964*.
7.4.1 The depth of the castellation should not, however, he in any
case less than 25 mm and the length of the castellation should be about four
times the depth. ,The centre-to-centre spacing of the castellations should
not be greater than the lever arm or 60 cm, whichever is less.
*Code of practice for plain and reinforced concrete ( second revision ).
26
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8-71 19 96
3 31 77
23 10 83
6 34 71
21 68 76
5 55 07
6 23 06
6 21 04
52 61 71
5 24 35
27 68 00
89 65 28
22 39 71
Printed at Dee Kav Printers. New Delhi. India