Analyze and design of suspension bridge using sap2000

VIVA-Tech International Journal for Research and Innovation Volume 1, Issue 4 (2021)
ISSN(Online): 2581-7280 Article No. X
PP XX-XX
VIVA Institute of Technology
9thNational Conference onRole of Engineers in Nation Building – 2021 (NCRENB-2021)
1
www.viva-technology.org/New/IJRI
Analyze and Design of Suspension Bridge Using SAP2000
Shubham Patil1, Samiksha Patil2
Samiksha Patil 3, Swati Patil4
1(Civil Engineering,Viva Institute Of Technology/ Mumbai University, India)
2(Civil Engineering, Viva Institute Of Technology/ Mumbai University, India)
Abstract: Structural design requires a full understanding and knowledge of all the components comprising the
structure. A suspension bridge is a type of bridge in which the deck (the load-bearing portion) is hung below
suspension cables on vertical suspenders. The design of modern suspension bridges allows them to cover longer
distances than other types of bridges. The main element of a cable suspended bridge is the cable system. Bridges
are normally designed for dead load, live load and other occasional loads. All loading and unloading conditions
in analysis and design are provided as per IRC codal specifications. The whole modeling of the suspension parts
of the bridge was done by using SAP2000. Suspension cable bridge having 1km span with single lane road, the
intensity of road is given has 20 numbers of vehicles each loaded with 350KN (heavy loading class A-A track load)
is analyzed by SAP2000. The output of the software presents results including moments, axial loads, shear force
and displacements. Moreover, moments and axial load at each node and at any point within the element can be
easily obtained from the software output. This thesis examines issues analysis and design calculation in over a
structure will safe under all conditions.
Keywords - Suspension Cable, SAP2000, Software Output, Design Calculations.
I. Introduction
A type of bridge where deck is hung below the suspension cable in vertical suspenders is known as suspension
Cable Bridge. The main element of a cable suspended bridge is a cable system. The main forces are tension in
cable and compression in towers. The cable is anchored at each end of bridge to maintain tension in this cable. The
design of modern suspension bridge allows them to cover longer distance than other types of bridge. The model
analysis is perform by analysis software SAP2000.
II. Headings
1.1 History of Bridge
The Manhattan Bridge, connecting Manhattan and Brooklyn in New York City, opened in 1909 and is considered
to be the forerunner of modern suspension bridges; its design served as the model for many of the long span
suspension bridges around the world. For bridges where the deck follows the suspenders, see simple suspension
bridge. The earliest suspension bridges were ropes slung across a chasm, with a deck possibly at the same level or
hung below the ropes such that the rope had a catenary shape.
The Tibetan saint and bridge-builder than tong Gallop originated the use of iron chains in his version of simple
suspension bridges. In 1433, Gallop built eight bridges in eastern Bhutan. The last surviving chain-linked bridge of
Gallop’s was the than tong Gallop Bridge in Dustmen route to TrashyYangtze, which was finally washed away in
2004. Gallop’s iron chain bridges did not include a bridge which is the standard on all modern suspension bridges
today. Instead, both the railing and the walking layer of Gallop’s bridges used wires. The stress points that carried
the screed were reinforced by the iron chains. Before the use of 6 iron chains it is thought that Gallop used ropes
from twisted willows or yak skins. He may have also used tightly bound cloth.
The first iron chain suspension bridge in the Western world was the Jacob's Creek Bridge (1801) in Westmoreland
County, Pennsylvania, designed by inventor James Finley. Finley's bridge was the first to incorporate all of the

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necessary components of a modern suspension bridge, including a suspended deck which hung by trusses. Finley
patented his design in 1808, and published it in the Philadelphia journal, The Port Folio, in 1810.
An interesting variation is Wareham’s Ferry Bridge in Burton-on-Trent, Staffordshire (1889), where the chains are
not attached to abutments as is usual, but instead are attached to the main 7 girders, which are thus in compression.
Here, the chains are made from flat wrought iron plates, eight inches (203 mm) wide by an inch and a half (38 mm)
thick, riveted together.
1.2 Definition
It is called suspension bridge a structure that allows crossing, at different levels, an obstacle a deck supported by
vertical or inclined wire hangers, which are the supporting structure, and hang flat on two towers.
1.3 Classification
The first and the main classification we will do it will be related with the number of spans of the bridge. In the
following chapters we will classify different types of bridges according to more specific parameters as the
continuity of the stiffening girders or the type of cable anchorages, but in general we can consider: single-span,
three-span with two towers or multi-span with three or more towers.
1.4 General Characteristics
Thus, the general characteristics of a suspension bridge are:
 Central span of length L plus two lateral spans the length of which ranges from 0.2*L to 0.5*L.
 Two main cables formed from high strength steel wires with certain flexibility supporting the whole
structure.
 Two towers, which can be made by metal or reinforced concrete, situated between the central span and
the two lateral spans providing a support to the cables.
 The deck with the stiffening girder that distribute concentrated traffic loading on this one avoiding local
deformations of the structure and providing the torsional and bending stiffness to avoid dangerous oscillations by
windage.
 Anchorages to secure cables to the ground, usually resisting horizontal forces that transmit these cables
thanks to the force of gravity.
1.5 Problem statement
The type of bridge to be adopted depends on the requirements of the location. Relevant Bridges as to be selected
before proceeding for the Design and Construction. The structural analysis of bridges for dynamic loading
conditions will give us deformations and shear force values. In the present study Suspension Cable Bridge is made
to find out magnitude of deformations.
1.6 Summary
In this chapter, we have studied about suspension bridge, the need for study, what are the different objectives and
the problem statement of our project is discussed. Details regarding the work carried out by different researchers
for study of Suspension bridges are dealt in next chapter.
III. METHODOLOGY
3.1 Data Collection
A Suspension Cable bridge is to be analyzed. The bridge plan consists of span 500m along X direction. Placing
tower at 100m from each end with height of tower 50m in Z direction. A main girder is placed at centre of tower.
Such that, it coincide with centre of tower. Over main girder, cross girder is placed at spacing of 4m C/C distance.
Hence, total number of cross girder is 125 along X direction. Placing deck over cross girder, width and depth of
deck is 18m and 5m respectively along Y direction. The diameter of main cable is 0.35m and the dip of cable at
mid span is 25m. Under reamed pile is placed at both ends of the bridge in order to anchor the main cable. From
the main cable, the suspenders are connected to the deck having diameter 0.2m. The suspension cable bridge is
designed and various results are compiled and analyzed.
3.2 Modeling in SAP2000
 Define Grid: After selecting a new model in SAP2000 we have to define the grid which has to be
suitable of our structure model.
 Edit Grid Data: Selection of Grid is done then edit grid lines in three directions such as X plane for
width, Y plane for length and Z plane for height.
 Define Material: In this case defining the material such as steel, rebar and concrete material properties
has to be used in Structure.

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 Define section properties: There are various types of sections are available. Such as concrete section,
steel section, rebar section and other type of sections.
 Draw elements: Draw sections properties which construct the structure.
 Define Loads: Define the load are acts on the structure. There are three types of loads. Such as dead
load, live load and load combination.
 Run Analysis: Run the structure analysis after drawing all the structure with elements, joint which has
to be used and all the loads.
3.3 Define Models :
 Main Cables: Two main cables formed from high strength steel wires with certain flexibility supporting
the whole structure. These cables drape in a parabolic curve between towers contributing to the overall visual
impression. The problem appears in SAP2000, where doesn’t exist a database of the different cables we can
choose so we will have to put directly the exact properties of our cable choice. The diameter of main cable is
0.35m.
 Tower/ Pylon: Two towers, which can be made by reinforced concrete, situated between the central span
and the two lateral spans providing a support to the cables. The towers are the primary responsible to provide
supports to the ends of the main span with enough height to provide the required cable sag above the level of the
Concrete girder and also to provide support to the deck. Height of the Pylon is 30m. And cross section is 2.5m x
2.5m.
 Deck/ Girder: The choice of the suspended deck is really important and the main reason is because the
deck load is entirely supported by the cable, towers, and anchorages. From this point we have choose it trying to
have the most economical deck with the best possible aerodynamic characteristics and with the highest tensional
stiffness. The deck with the stiffening girder that distribute concentrated traffic loading on this one avoiding local
deformations of the structure. The Properties of concrete is used for Precast Girder is M35 Grade of concrete.
 Hangers/ Suspenders: The main function of the hangers is to connect the deck and the stiffening girder
to the main cables. The diameter of hangers is 0.2m. Spacing between these suspenders is about 3m C/C. The
properties of steel are HYSD500.
 Foundation: The Foundation used for structure is Pile foundation. It consists of six helical shape
foundation of 1m in Diameter. Its concrete properties are M35 grade of concrete. Steel are used for the foundation
is 25mm Diameter bar. Provided Pile cap on top of the pile foundation.
 Piers: After the pile foundation is done piers are constructed on Pile cap. Height of the pier is 20m. M35
Grade of concrete to be used for constructing. Rectangular Piers are constructed of size 2.5m X 2.5m.
 Anchorage: Anchorages to secure cables to the ground, usually resisting horizontal forces that transmit
these cables thanks to the force of gravity. We can have two different ways of connecting the main cable with the
structure, so we can have externally anchored or self-anchored types. The second ones are fixed to the deck instead
of an external anchorage and in consequence the axial the axial compression is carried into the girders.
IV. table no 1: loAD calculation
Load Calculation :
Left span length 100 m
Middle span length 300 m
Right span length 100 m
Deck width 18 m
Pier Height 20 m
Pylon Height 30 m
Minimum middle sag 25 m
Left number of Division 3

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Middle number of Division 10
Right number of Division 3
Diameter 0.35 m
Main Cables
Area 0.0962 m2
Diameter 0.2 m
Hangers
Area 0.0314 m2
V. Conclusion
The analysis of the Composite cable bridge of 1000m span with double lane road, the intensity of road is given as
20 numbers of vehicle each loaded with 350 KN (Class A-A tack load) is carried out by using SAP2000. These
results including Bending moments, shear force values at each node at every point within the element can be easily
obtained from the software output. The maximum bending moment and shear force values are analyzed by
software and compared with manual design of Composite Cable Bridge
Acknowledgements
We are using this opportunity to express our gratitude to everyone who has supported us throughout the
completion of this project. We are thankful for their guidance, constructive criticism and friendly advice, during
the project work. We express our gratitude to Prof. Ashish Shetty for giving us an opportunity to carry out project
on “Analyze and Design of Suspension Bridge by Using SAP2000”. We would also like to thank Prof. Lissy Jose
, Head of Civil Department and Dr. Arun Kumar, the Principal for their whole hearted support. Lastly, we
express our gratitude towards all those who directly or indirectly helped us in the completion of our studies.
References
[1] Manabu Ito, ”Cable Supported steel bridges: Design problems and solutions”,Jounal of Constructional Steel Research, Volume
39, Issue 1, pp 69 - 84, August 1996.
[2] Chatterjee, P. K; Datta T.K; Surana C. S” vibration of suspension bridges under vehiculare movement”, Journal of Structural
Engineering, Volume 120, Issue 3, pp 681 - 703, March 1994.
[3] Moisseiff, L. S and Lienhard, F.,” Suspension bridge under action of lateral forces”, American Society of Civil Engineers,
Volume 98, Issue 2, pp 1080 – 1095, 1934.
[4] Saafan, A. S, “Theoretical analysis of suspension bridges”, American Society of Civil Engineers, Volume 94, NO ST4, PROC
PAPER 4885, PP 1 – 11, 1930.
[5] D. S. Carder, Observed vibrations of bridges, Bulletin Seismological Society of America 27 (1937) 267.

Analyze and design of suspension bridge using sap2000

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