The Argued Flyover Pakistan

The Technical Reality Behind the Viral Bridge on Social Media

Recently, there has been a lot of discussion on social media about the design of a particular bridge, 

especially focusing on the reasoning behind its additional loop. 

People are sharing their engineering interpretations of this unusual design.

First, it's important to clarify that this is not a computer-generated image. The bridge in question is real and was constructed in 2017 on Raiwind Road, Lahore.

The key question being asked is: Why was the additional loop included in the flyover, when the railway crossing could have been bypassed with a straight road?

The answer lies in the constraints of the location. There wasn't enough space on either side of the flyover to build a longer, straight road. If a direct road had been constructed, the slope of the railway overhead bridge would have been too steep, violating the principles of highway engineering. Several key factors must be considered when designing bridges, such as standard gradients, sight distance for vehicles to see each other, and maintaining control of brakes and speed on descents.

In highway engineering, the maximum allowable slope for ascents and descents is typically between 6% and 10%, ensuring that vehicles can travel safely. To achieve this standard slope within the available space, the designers incorporated the additional loop, which increased the length of the road while reducing the steepness of the incline.

This engineering solution may seem unconventional, but it effectively adheres to safety standards while accommodating the physical limitations of the area.