The USD 150 million Bengaluru International Airport Limited (BIAL), located 40 kilometers north of the Indian garden city’s central business district, was a design and build venture of L&T, spanning 4300 acres and catering to 11 million passengers annually. The long-span precast roof element is a unique feature of the Passenger Terminal Building. Conceived after careful deliberation, the roof element met the varied requirements and suited the need for quality and fast construction. The resulting aerofoil-profiled design, it’s construction method and performance delivered highly on aesthetics, optimal space usage, schedule adherence, quality standards, lighting and energy savings. The roof grid was divided into modular bays to accommodate four elements, each approximately 6 m wide, 3 m high and 24 m long. The elements, with a varying thickness from 160 mm to 250 mm weighed about 120 MT. Incorporating skylights in the roof element produced uniform, diffused light throughout the main hall and contributed to energy savings. Self compacting concrete of M50 grade and post-tensioned cables with weld-mesh rebars were used in the construction. The element was cast in a semi- mechanized yard, minimizing labour and cycle time and aiding repetition. Erection was carried out using a mechanized strand jack arrangement. The challenge was to get the element exactly as per design, and place it in position within the dimensional tolerances anticipated for the total supporting system.
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