Challenges Encountered for Foundation of Durgam Cheruvu Extradosed Bridge in Hyderabad

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The paper describes the design and construction challenges for foundations of the Durgam Cheruvu extradosed bridge in Hyderabad, which connects Madhapur with Jubilee Hills. The site’s steep, undulating terrain, limited access, heavy urban traffic, and proximity to residential areas constrained construction methods.<br /><br />Geotechnical investigations, including 17 boreholes, found 10–15 metres of completely weathered and disintegrated granite above moderately weathered to fresh bedrock. Granite outcrops and large boulders occur throughout the alignment. Although rock-socketed piles were initially a conventional option, pile-drilling equipment was difficult and risky to mobilize on the terrain. Blasting was also restricted because of noise concerns, while other drilling methods required heavy machinery, cranes, or lengthy operations.<br /><br />The project team therefore adopted large shallow foundations founded on weathered granitic rock. Foundations reached dimensions of up to 20 × 18 × 4 metres, requiring substantial excavation and levelling; uneven rock surfaces beneath the slabs were levelled with plain cement concrete. To break granite boulders without conventional blasting, the team used soundless chemical demolition agents. Hydrated in pre-drilled holes, these agents expand and generate pressure that fractures the rock.<br /><br />The study concludes that, despite difficult geology, terrain, access, and urban constraints, shallow foundations and chemical cracking provided a successful alternative to pile foundations and blasting.

Keywords

Durgam Cheruvu bridge

extradosed bridge

Hyderabad

foundations

geotechnical investigation

granite rock

shallow foundations

chemical demolition agent

rock excavation

urban construction constraints