Kochi: The problems with the Palarivattom flyover first came to notice during an inspection done by the chief technical engineer after holes emerged. The inspection found problems with the deck continuity method that was used instead of expansion joints. Deficiencies were found in the tarring, too.

In Palarivattom, the deck continuity method was used instead of expansion joints between spans to minimise the jumping of vehicles while passing through the flyover. This method involves concreting together the girders, deck slabs and pier caps on more than one spans.

Problems right from the designing stage

Following the inspection in 2017, another inspection by a private agency on behalf of the National Highways Authority of India in 2018 also pointed out deficiencies in the construction but the authorities did not come forward to carry out repairs.

During the second inspection that was conducted for the NHAI, cracks were found in the 1,2,3,7,10, and 12 pier caps. The recommendation was to carry out repairs by banning the movement of heavy vehicles. However, Roadways and Bridges Development Corporation of Kerala (RBDCK) decided to seek the expert advice of IIT-Madras. IIT’s study also found serious deficiencies in the construction of the flyover.

Inspection by E Sreedharan, experts

The state government asked E Sreedharan of the Delhi Metro Corporation to inspect the flyover. On June 17, Sreedharan, concrete expert Prof Mahesh Tandon and IIT-Madras professor P Alagusundara Murthy inspected the flyover. Cracks were found in 17 of the 19 spans and 97 of the 102 girders.

It was recommended that all 17 spans be demolished and rebuilt. It was suggested that the metal bearings used between the spans and the pillars were substandard and should be replaced and that the pillars should be reinforced with concrete jacketing.

Sreedharan also pointed out that 16 of the 18 pier caps need to be replaced and that three of them posed serious danger.

Decision to reconstruct flyover

The government received the IIT's first report, which included recommendations to do away with deck continuity and instead build expansion joints, provide carbon fibre wrapping for pillars, and for re-tarring. A second report called for the strengthening of the girders and pillars.

Even though the company started the first phase of work, the government appointed a special committee to study Sreedharan's recommendations and the IIT’s report. The IIT did not specify for how long the flyover would last if the repair works costing Rs 7.7 crore were carried out. Sreedharan's suggestion that it would last for 100 years if rebuilt was given priority.

The Union Ministry of Roads and Highways also wrote to the state government saying the flyover was in a weak condition.

The flyover at a glance

Length 750 m, four-lane flyover

Project consultant: Kitco; Nodal agency: Roadways and Bridges Development Corporation of Kerala (RBDCK); Design: Nagesh Consultants, Bengaluru

Construction cost - Rs 39 crore

Maintenance - Rs 3 crore

Reconstruction: Rs 18.71 crore (although the DMRC will use the surplus from various projects for the reconstruction, the RBDCK will take legal action to recover from the contracting company the money spent originally)

Expenditure on IIT studies: Rs 56. 50 lakh

Inadequacies in the flyover construction

Design flaws and failure of Kitco to oversee the construction

Defects in the use of the deck continuity method instead of using expansion joints

Problems with the bearings of the pillars

The use of low-quality construction materials for the flyover; the M22 grade concrete mix used to build houses and rooms were used to build the flyover, what was required was M35 grade.

Cracks in the pier caps of 1,2,3,7,10,12 pillars

Cracks in the central span and girders

Girder installation not done properly. The height difference was obvious.