Specials

Road structures can necessitate horizontal and vertical formwork

June 2019
Road construction necessitates formwork for retaining walls, culverts, tunnels and flyovers (in-situ obligatory span or precast segments). The type of structure is the foremost factor influencing the choice of formwork. “Other factors influencing the choice of formwork are desired finish, site safety needs, targeted cycle times, availability, repetitions needed, weight of the formwork and handling ability, whether single use or multipurpose, repairs and maintenance costs, training cost and client specifications,” says Sachin More, Head, Formwork, JMC Projects (India).

When JMC Projects (India) started to implement the Mankhurd flyover project, the structural design majorly influenced the choice of formwork. The horizontal parts of the flyover were to be built with precast segments in some sections and in-situ concrete in others. The formwork had to be chosen accordingly.

“We opted for a customised cribs formwork for the in-situ concrete because this formwork suited the site conditions both technically and economically,” explains More. “We had to work in a confined area with ongoing traffic, so using cribs allowed us greater spans for passing traffic. Cribs formwork can be easily erected and dismantled with the help of a crane and supports a greater slab thickness. There could have been several other options like as deck, shoring or flex formwork; however, we preferred to use our own asset bank.”

“For precast segments, custom-made formwork in mild steel is suitable and can be designed as per the desired loading conditions unlike modular panels,” adds More. “This formwork has a two to three-day cycle; it is easy to align and gives the desired finish. It can be best handled with hydraulic systems. As we had to separately cast the peir (column) and the peir cap because of the large size, we needed separate vertical formwork for these elements.” Custom-made formwork in mild steel, which supports greater loads/pressured, was preferred over other modular formwork. This had a two to three-day cycle and necessitated the use of a crane.

JMC Projects (India) fabricated all this formwork itself.

CHARU BAHRI

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