Narendra Modi Stadium, commonly known as Motera stadium, is quickly leaving its mark on the global sports map.
Overview
Eclipsing Melbourne Cricket Ground as the world’s largest cricket stadium and standing in second place as the largest overall sports stadium, Narendra Modi Stadium (commonly known as Motera Stadium) is quickly leaving its mark on the global sports map. mondo | STADIA caught up with Walter P Moore experts Viral Patel, Mark Waggoner, and Abhijit Shah to discuss the inner workings of this unique structure that galvanized an entire country.
The roof structure at Motera Stadium was a particularly complex part of the project, with Walter P Moore serving as roof structural engineer. The city of Ahmedabad, where Motera Stadium is located, is in a level three seismic zone, meaning that the roof needed to be lightweight to reduce seismic demand and develop an economical roof system. Viral Patel, Director of Design at Walter P Moore, explained further: ‘Seismic forces are proportional to the mass of the structure. Therefore, very early in the design phase, it was decided that the best option would be to incorporate a lightweight, cable-supported tensile membrane roof. Additionally, we decided that the reinforced concrete bowl and the roof structure needed to be independent of each other. This decision was motivated by the seismic hazard for the project.
Achieving a good performance of structure economically under seismic events was the primary reason for separating the roof from the bowl. The bowl is a reinforced concrete structure that is inherently very heavy. The roof of Motera Stadium is a lightweight structure made up of tensile membrane, cables and a steel perimeter frame. If the bowl and roof structures were not separate from each other, it would have created a very high seismic demand on the roof.
The prescriptive code requirements also allow inelastic behaviour in a reinforced concrete structure when enhanced seismic detaining is adopted. The lightweight roof structure, on the other hand, is not arranged to readily accommodate inelastic behaviour. Without separating the bowl from the roof, the bowl would have been subjected to an amplified seismic demand from the roof.
