Sumanahalli flyover: Report points to major distress in bearing support, expansion joints

Distress treatment, repairs to cost the BBMP around ₹40 lakh

Major distress in the bearing supports, honeycombed concrete, damages near the expansion joints and development of cracks... this is what the company that looked into the structural stability of Sumanahalli flyover found.

In November, a portion of the road on the flyover crumbled and collapsed. The Bruhat Bengaluru Mahanagara Palike (BBMP) asked a company – Bureau Veritas (India) Pvt. Ltd. – to study and submit a report on the flyover's structure and stability. Bureau Veritas claims to be leader in testing, inspection and certification.

In its third interim report that was submitted to the BBMP recently, the company maintained that distress in the structure needs to be addressed urgently.

The BBMP, under the guidance of Bureau Veritas, has now sought a quotation from three companies to take up distress treatment and repairs on the flyover. Sources said the distress treatment and repairs would cost the civic body around ₹40 lakh.

“We will get the quotation for the repairs by either Thursday or Friday. The same is likely to be finalised by Monday,” said a source.

Sustaining normal traffic

Bureau Veritas maintained that the flyover will be capable of sustaining normal vehicular traffic only after carrying out restoration measures as per its recommendations for methodology of repair.

The report, a copy of which is with The Hindu, states that the core tests carried out on the deck slab concrete revealed that in a majority of spans, the required strength was not achieved. The independent analysis of the deck slab revealed that the stresses developed were less than permissible limits for the strength of the existing concrete.

In the report, Bureau Veritas notes it had sought original design calculations from the BBMP. BBMP officials had sought the same from the Bangalore Development Authority (BDA), which is yet to furnish them.

“The BDA took up construction of the flyover in 2007. It was opened for vehicular movement in 2010; and handed over to the BBMP in 2016,” a source said.

The first interim report was submitted on November 6, in which the company stated that light vehicular traffic could be allowed after the asphaltic wearing coat had hardened. It was following this that vehicular movement was allowed on the flyover.

Sources said the second interim report, which was submitted on November 17, pointed to some of the bearings exhibiting signs of rusting, honeycombed concrete in some of the bearing seating of the cross girders, minor cracks, dampness and lime leaching, damage to concrete along the steel inserts. There were also some indications of development of minor distress in vulnerable areas like wearing coat, expansion joint, kerb, precast slab.