17 reinforced cement concrete spans of Palarivattom flyover in Kochi to be dismantled – The New Indian Express


Express press service

KOCHI: The Palarivattom air bridge, closed since May for repairs, is about to undergo a major makeover. A report filed by Delhi Metro Rail Corporation (DMRC) Senior Advisor E Sreedharan to the government recommends the dismantling of all 17 Reinforced Cement Concrete (RCC) spans.

In the report submitted to Chief Minister Pinarayi Vijayan on July 3, the subway man recommended that there is no reinforcement needed for the foundation. Similarly, no reinforcement of the special spans of prestressed concrete beams (PSC) was necessary. Instead, the metal bearings should be replaced with sturdier bearings. However, modifications must be made to the piers, headers and spans of the RCCs.

“The stacks and stack caps should be reinforced with an appropriately designed RCC coating. The vertical reinforcement of the pillar casings must be brought to the pile cap reinforcement and glued. All 17 RCC spans are to be dismantled and replaced with PSC beams with at least one diaphragm in addition to the end diaphragm beam and a new deck slab supplied.

The continuity of the deck slab must be ensured above the piers,” said in the report. DMRC estimated 18.71 crore restoration work to be done. This includes `2 crore for dismantling and transporting RCC spans, `1.71 crore for revetment piers and jetty caps and `15 crore for new PSC bridges. The deadline for restoration is 10 months. Visual cracks were observed in 97 of the 102 RCC beams. A crack width of up to 0.38 mm was recorded compared to the allowable limit of 0.236 mm.

These noted crack widths were without an active road. With a road under tension, the width of the cracks is likely to increase further. In a coastal environment, this leads to corrosion of reinforcement affecting strength and durability. Sreedharan is also skeptical about reinforcing concrete with low viscosity epoxy resin.

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“With the quality of the concrete in doubt I have strong reservations as to whether wrapping with carbon fiber fabric can restore this beam to the required structural strength and even if restored what the durability would be. of these beams? Perhaps no more than 20 years, while a life expectancy of 100 years is required for these beams,” the report read. According to Sreedharan, if the cost estimated by IIT Madras is more 50% of the replacement cost, the option is then a total replacement of the RCC beams by PSC beams.


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