Comparison of sliding and conventional formworks in dam tunnel at the Meninting Dam in West Nusa Tenggara

Tunnels are underground structures that are longer than the width of the excavation. The Meninting Dam tunnel work is one of the main jobs with a very high level of difficulty. This tunnel has a length of 243.44 m and a diameter of 9.4 m. The Meninting Dam Tunnel has a function as a temporary diversion of water from the river to the tunnel so that the main structure of the Meninting Dam is not disturbed by river flow. The tunnel concreting work consists of 3 (three) items, namely reinforcement, formwork and concrete casting. Of the three work items, the work that has the potential to be accelerated is formwork. In the Meninting Dam development project there are two types of formwork, namely conventional formwork and sliding form formwork. Based on the results of calculating the cost, time and quality requirements of the comparison of using conventional formwork with sliding form formwork, it is found that the difference in costs obtained using conventional formwork cheaper than sliding form formwork, and the time difference required in completing the formwork work using conventional formwork and sliding form formwork is 83 (eighty three) days and the quality comparison that has been obtained is that conventional formwork is not neat, not smooth and leaves a lot of wood waste while the quality of sliding form formwork is tidier, smoother and leaves no waste.