Steel Composite Bridge Construction R1

Composite construction in Bridge Deck systems
A Solution in City Environment for Speedy
Construction with Industrialized Full Length
Prefabrication
By
S. P. Khedkar ,
Kishore Saxena - XCC Engineers & Planners
Presentation in CEMCON 2014 National Conference on "Composite Construction & Modern
Concrete“ Pune 12th Sept 2014
1

Typical Site Conditions and Basic
Requirements in Construction of Urban
Flyovers.

Typical Site Conditions and Basic Requirements in
Construction of Urban Flyovers.
Flyovers have become a basic
need of any busy and growing
city to avoid traffic congestion
and smooth traffic flow at busy
intersections.
They Have to be constructed on
the busy roads and in
overcrowded environment.
Causing Minimal disturbance to
traffic
Ensuring Safety of the citizens.
Presentation in CEMCON 2014 National Conference on "Composite Construction & Modern Concrete“ Pune
12th Sept 2014
3

 During tight
construction schedule, -
Basic Demand
 Without Closure of
existing Roads.
 In Restricted time of
small working windows
during late night ,
especially for
superstructure erection.
Presentation in CEMCON 2014 National
Conference on "Composite Construction &
Modern Concrete“ Pune 12th Sept 2014
4
Typical Site Conditions and Basic Requirements in
Construction of Urban Flyovers.

Normal Methods of Construction of Urban Flyovers
• Precast Segmental Construction
• Precast Full Length PSC girders
with Cast in Situ Deck
• Prefabricated Structural Steel
Girders with Cast in Situ RCC
Deck slab –Normally Not
preferred due to higher cost
and maintenance issues.
5

• Use of Precast or
Prefabricated components
for superstructure help in
reduction of construction
time, as superstructure
components can be kept
ready elsewhere, when
construction of
foundations and
substructure is in progress.
6
Use of Precast / Prefabricated Components for Construction of
Urban Flyovers.

• Erection of such
components can be
planned during night
hours, when the traffic is
minimal; thus causing least
hardships to the general
public
• Many flyovers have been
constructed in our country
using full length precast
prestressed girders, and
cast in situ deck slab.
7
Use of Precast / Prefabricated Components for Construction of Urban
Flyovers.

• Flyovers with full length
prefabricated girders in
structural steel and
composite RCC deck slab are
very few.
• This paper discusses use of
such structural system for
congested cities.
8
Use of Precast / Prefabricated Components for Construction of
Urban Flyovers.

Urban Flyovers in Precast Prestressed Concrete :
Salient Features
• Typical spans Range between 20 to 30m.
Precast prestressed girders can be transported
from casting yard and erected at site. In situ
deck slab can be cast on the erected girders.
• Over intersections the span length is dictated
by the site conditions. The obligatory spans
are much longer , ranging between 40 to 50
m.
• If full length precast girders with deck slab are
used for typical spans, Obligatory spans need
different structural system like cast in situ box
girder; as transportation and erection of
precast girders of longer length is not feasible
in urban conditions .
9

Urban Flyovers in Prefabricated Structural Steel
Girders: Salient Features
• Typical spans Range between 20 to 30m.
Prefabricated girders can be transported from
fabrication yard and erected at site. In situ deck
slab can be cast on the erected girders.
• Over intersections the span length is dictated by
the site conditions. The obligatory spans are
much longer , ranging between 40 to 50 m.
• Girders for obligatory spans can be fabricated in
units of shorter lengths suitable for transportation
and erected on staging. The individual units can
be spliced at site.
• Thus Obligatory spans need not have different
structural system like box girder. All the spans can
have uniform appearance.
10

Different Deck Systems for Structural
Steel Girders with Composite Deck Slab

Different Deck Systems for Structural Steel Girders with
Composite Deck Slab
12
1. Plate Girders with Cross
Diaphragms and Cast in
Situ Deck Slab
2. All components of the steel
concrete composite deck
with shear connectors and
the Composite action is
explained in the sketch.

Composite Deck Slab
13
Examples of Plate Girders with Cross diaphragms
and Cast in Situ Deck Slab

Composite Deck Slab
14

Composite Deck Slab
15

Composite Deck Slab
16
Examples of Fabricated Plate Girders and Erected
Girders at site

Composite Deck Slab
17
Example of Full Length Steel Girder being
Transported to site

Composite Deck Slab
18
and Cast in Situ Deck Slab a Flyover in Kolkata

19
Examples of Box Girders with and Cast in Situ Deck
Slab
Composite Deck Slab

20
Example of Box Girders with and Cast in Situ Deck
Slab- Flyover Bridge at Kolkata – Obligatory Span
Composite Deck Slab

21
Example of Innovative Composite Steel Truss with Cast in Situ
Deck Slab
Composite Deck Slab

Comparison between
Precast Prestressed Girders and Steel
Composite Girders

Comparison between
Precast Prestressed Girders and Steel Composite Girders
23
Precast Prestressed Girders: Prefabricated Steel Girders:
Shape: I Girder , Box Girders, Multiple
Box Girders
Shape: I Girder , Box Girders, Multiple Box
Girders
Suitable span length for Urban flyovers :
20 to 30 m
Suitable span length for Urban flyovers : 20 to
30 m, or longer spans with In Situ splicing.
Weight of girders: Range between 40 to
90 T. Normally not precast in shorter
lengths, although Spliced girders have
been adopted in some flyovers.
Weight of girders: Range between 20 to 40 T.
Individual units of shorter lengths can be used
to restrict the length and weight for
transportation and erection.
Need Special setup of casting yard for
precasting girders.
Need Special setup of fabrication yard for
prefabrication of girders. However, girders can
also be fabricated in workshops, when special
setup is not needed.

Comparison between
Precast Prestressed Girders and Steel Composite Girders
24
Precast Prestressed Girders: Prefabricated Steel Girders:
Need heavier cranes and erection
gantries for erection at site.
Need cranes and erection gantries of
relatively smaller capacity for erection at
site.
Appearance: Generally considered as
acceptable, although tends to gather dust
on bottom bulbs and spoil appearance.
Appearance: May not be considered as
acceptable, due to stiffeners and cross
diaphragms.
Appearance can be improved by adopting
Trapezoidal girders, which do not
accumulate dust.
Appearance can be improved by adopting
multiple box girders, and providing
stiffeners inside the box. Cross
diaphragms can also be U shaped for
uniform appearance.
Maintenance: Normally the girders do
not need maintenance.
Maintenance: The girders and cross
diaphragms need regular maintenance in
the form of painting to avoid corrosion.

Discussion and Conclusion
1. Use of Prefabricated Steel Girders is relatively
rare in India due to Cost and Maintenance
considerations. However , the system has
following advantages:
a. Weight of girders is much less, and needs lower
capacity trailers for transportation, and lighter
cranes for handling and erection.
b. Can be advantageous for construction on narrow
roads, where large trailers and cranes can not be
deployed.
25

Discussion and Conclusion
c. Appearance of girders may not be acceptable
due to skeletal nature, visible stiffeners and
bracings. But can be improved by adopting
multiple box girders and provision of stiffeners
entirely inside box girders.
d. Need of Regular Maintenance may be an
important consideration against use of Steel
girders. However, Multiple box girders, if sealed
from ends, need painting only from outside, on
plain surfaces, and can be done with relative
ease.
26

Composite construction in Bridge Deck systems
A Solution for Urban Flyovers.
The Authors have made an attempt to present a
relatively rare structural system in India viz.
Composite Steel Girders for Urban flyovers.
The authors are grateful to CEMCON 2014 for
accepting their paper and extending invitation to
present the same in the National Conference on
“Composite Construction and Modern Concrete”.
Thank You.
27

Steel Composite Bridge Construction R1

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