Case Study of Flyover /Bridge

And Various problems and it’s

solution

The objective of this study is to find out the different problems arising while and after construction.

Moreover, We have also found remedial solutions to it. Our objective is to give fundamental knowledge regarding construction and maintenance of Flyover Bridge and how to minimize the problems related with all the functions of Flyover Bridge..

To make the roads easily accessible for day to day traffic.

OBJECTIVE

Definition

A bridge is a structure providing passage over an obstacle without closing the way beneath. The required passage may be for a road, a railway, pedestrians, a canal or a pipeline. The obstacle to be crossed may by a river, a road, railway or a valley.

Components of a Bridge

The main parts of a bridge structure are as below:

Decking, consisting of slab, girders, trusses, etc… Bearings for the decking.Abutments and piers. Foundations for the abutments and piers.

River training works, like revetment for slopes at abutment, aprons at bed level, etc.

Approaches to the bridge to connect the bridge proper to the roads on either side;

Handrails, guard stones, etc…

Importance of bridge

To reduce the travel time.To minimize the congestion on roads.To reduce the accidents arising day by day.When the widening of road cannot be done a 3rd dimension is to be used by constructing a flyover.

How are Bridges Used? Walkways  Highways/Roads

Railways

Pipelines  Connecting Lands

Crossing Rivers

Stadiums

Roofs  Arch

Truss

Cantilever

Cable Stayed

Suspension

Flyover

Reason behind going for a flyover

As the traffic on the road goes on increasing and we don’t have any space

left in both the dimensions, then the only option left will be to go to the third dimension and that is done through

flyover construction.

Flyover

It is a bridge that carries one road or railway line above another either

with or without subsidiary roads, for communication between the two.

TYPE OF FLYOVER BRIDGE

Road Crossing

Simple FlyoverCloverleaf Junction

Railway Crossing

At railway crossing where there is high traffic congestion in terms of the frequency of trains

passing by or the traffic on the road, in both the cases the flyover should be provided along the road. Here the flyover becomes indispensable.

Railway Crossing

Simple Flyovers

In this case, the main road is used for fast traffic, which is made to pass at a high level by a

bridge, providing ramps on both the approaches; and the slow traffic is made to pass underneath. Thus the traffics pass at two different levels, and

leave no chance for an accident.  

Road Crossing

It requires a very large area of land. All conflicting streams of traffic are avoided, and so traffic can move at its own speed. This is

more advantageous than a roundabout, as there is no necessity for weaving and slowing down

of traffic.

Cloverleaf Junction

Methodology Of Flyover

Problems Arise In Different Aspect Of Flyover

Earth work Surplus excavated earth not leveled and neatly dressed at the disposal place. Less sand filling done under floors. Proper compaction of earth under floors not done. Compaction of earth work in filling not done as stipulated in the contract. Lead chart for disposal of surplus earth not maintained. Excavation of foundation less than specified in drawing.

Concrete work.

i) Oversize/ disintegrated/soft aggregate used.

ii) Sand with more silt content used.

iii) Honey combed concrete.

iv) Concrete found bulged and not in plumb.

v) Less thickness of PCC.

vi) Proper overlaps in reinforcement not provided.

vii) Reinforcement found exposed.

viii) Lesser diameter binding wire used.

ix) Expansion joint not properly located/ provided.

x) Improper curing and compaction

xi) Timber form work used through contract provides for steel form work.

xii) Clear cover to reinforcement not as per drawing.

Steel Worki) Non-standard steel sections used

ii) Priming coat either not done or poor quality priming coat done on steel works

iii) Tack welding done instead of continuous welding

iv) Extra slag of welding not removed

v) Thickness of sheets in rolling shutter found less

vi) Inferior quality hinges and fittings provided

vii) Steel hinges in M.S. frames not fixed by cutting slots.

viii) Flash butt welding not done in steel windows

Major Problems With Bearing Failure

Excessive LoadsOverheatingNormal Fatigue FailureReversal LoadContaminationLubricant FailureMisalignmentCorrosionLoose FitTight Fits

General Problems With Solutions

SolutionsExcessive LoadsThe solution is to reduce the load or redesign using a bearing with greater capacity.Normal Fatigue Failure The remedy is to replace the bearing or consider redesigning to use a bearing having a greater calculated fatigue life.Contamination

Clean work areas, tools, fixtures, and hands help reduce contamination failures. Keep grinding operations away from bearing assembly areas and keep bearings in their original packaging until you are ready to install them

Corrosion Correct by diverting corrosive fluids away from bearing areas and use integrally sealed bearings whenever possible.Misalignment Inspecting shafts and housings for run out of shoulders and bearing seats; use of single point-turned or ground threads on non hardened shafts and ground threads only on hardened shafts; and using precision grade locknuts. Tight FitsCorrective action includes a decrease in total interference.

CorrosionCauses Of Corrosion Water Permeability Oxygen Permeability Carbonation Chloride Ingress

Prevention Methods1) Keep concrete always dry, so that there is no H2O

to form rust. Also aggressive agents cannot easily diffuse into dry concrete. If concrete is always wet, then there is no oxygen to form rust.

2) Stainless steel or cladded stainless steel is used in lieu of conventional black bars.

3) A portion of the chloride ions diffusing through the concrete can be sequestered in the concrete by combining them with the tricalcium aluminate to form a calcium chloro-aluminate (Friedel’s salt). It can have a significant effect in reducing the amount of available chlorides thereby reducing corrosion.

4) Electrochemical injection of the organic base corrosion inhibitors, ethanolamine and guanidine, into carbonated concrete.

5) The rougher the steel surface, the better it adheres to concrete. oxidation treatment (by water immersion and ozone exposure) of rebar increases the bond strength between steel and cement paste to a value higher than that attained by clean rebars. In addition, surface deformations on the rebar (such as ribs) enhance the bond due to mechanical interlocking between rebar and concrete.

Literature Review1. Jinghui Wang (et.al.2011) Presented Problems and

solutions in the protection of historical urban areas

2. S.K. Mahajan (et.al.2013) Presented New Concept of Traffic Rotary Design at Road Intersections

3. D.M. Siringoringo (et.al.2011) Presented Vibration Characteristics of an Overpass Bridge During Full-Scale Destructive Testing

4. R. K. Gupta (et.al.2013) Presented Closed Form Solution for Deflection of Flexible Composite Bridges

5. Sarfaraz Hashemkhani Zolfani (et.al.2013) Presented Selecting the Best Design Scenario of the Smart Structure of Bridges for Probably Future Earthquakes

6. Tehmina Ayub (et.al.2014) Presented Effect of overloaded vehicles on the performance of highway bridge girder: A case study

Thank You