ENGINEERING LESSONS: EPISODE 22 - OPTIMIZED LIVE LOADED VIADUCT BRIDGES
OPTIMIZED LIVE LOADED VIADUCT BRIDGES
In the Present state of the art, a
Bridge Engineer usually optimize the design component in four ways.
This article will discuss about the possibility to optimize the design loads with Effective Live Load Concept.
Problem Statement:
Criteria 1:
The vehicle volume in
the road is majorly classified into two types namely passenger vehicle segment
& commercial vehicle segment. Around 90% of vehicles on road are passenger
vehicle segment and only 10% of the vehicle is under commercial vehicle
segment. Commercial vehicles are higher weight compared to passenger vehicles.
But a Bridge Engineer is pulled to compulsion in designing the bridge for the
governing vehicle load
that is a commercial vehicle, even though their volume is less compared to a
passenger vehicle.
As per Indian scenario, IRC Class AA & A are far higher than the normal vehicles.
Criteria 2:
In a densely populated city there will be always an alternative
route to reach a destiny and this criterion is going to help us to build the
solution.
In common practice, a Bridge Engineer shall design the bridge to carry all type of traffic whose vehicle load which will be in the range of 5 to 15kPa. But now in this new approach, the Bridge Engineer shall design a bridge by controlling the traffic to only passenger segment vehicles whose weight is less than 5 kPa and by restricting the commercial vehicle traffic.
OPTIMIZED LIVE LOADED viaduct
bridge which exclusively carries only passenger vehicle segment which is less
than 5 kPa.
This concept
developed to implement only in the densely populated cities to ease the traffic
congestion, where there is an existing alternative route to transport
commercial vehicle segments.
Advantages of the OPTIMIZED LIVE LOADED viaduct bridge:
If the bridge designed for OPTIMIZED LIVE LOADED bridge with a live load less than 5 kPa then during a fire emergency in the bridge, a fire engine can’t access the spot by traveling over the bridge. Since the bridge is not designed for fire engine vehicle load. But this concept is developed to facilitate inside a city where there will be easy for a fire engine to access the affected area from at-grade to put off the fire.
A crane cannot access the location by traveling over the OPTIMIZED LIVE LOADED bridge since the bridge is not designed for crane loading. But as mentioned in the previous scenario the crane can access the location by reaching it at-grade.
Incident Date: 26/10/2020 Early Morning
