36.3m single-slab concrete flat roof on 5,000-seat hall in Jaipur enters Guinness Book of World Records

A 5,000-seat hall in Jaipur, India, has entered the Guinness Book of Records for having the largest single-span reinforced concrete flat roof. Measuring 36.3m, the roof comprises a waffle slab that employs a criss-cross square grid of deep ribs that are supported by a perimeter beams measuring 1.4m x 2.7m supported by eight columns.

“We faced several engineering challenges while designing a structure of this size. Our major concern was to minimise the deflection, or the sagging of the roof,” says Deepak Sogani, chief executive officer of NM Roof Designers, the structural engineer behind the design. This was overcome by using a 200mm-thick post-tensioned slab.

The hall is situated in the old walled city in Jaipur.