Galala Bridge Scour Model on Ambon's Way Ruhu River

Abstract

The scouring that occurs on the abutments and pillars of the bridge is total scour, which is a combination of local scour and general scour. It can also be a combination of localized scour, generalized scour and localized scour / constriction scour. Bridge collapses are often the result of scouring. The potential for flooding can increase riverbed degradation, riverbed degradation and local scouring, which adds to the threat of bridge sub-structures. The galala bridge is located in the lower reaches of the Way Ruhu river with a stretch length of 60 m. Physically, this bridge has been built for a long time so it needs to be evaluated for scour depth by mathematical modeling using the HEC- Ras 6.4.1 application. Scour modeling uses the CSU method and the Froechlich method. Based on the simulation results using three flow conditions against the 10, 25 and 50 year recurrence periods and using physical properties test data (grain size analysis, specific gravity test, and soil content weight test) from the Ambon State Polytechnic Material Test laboratory from soil samples around the Way Ruhu estuary showed that the scouring depth reached the base of the bridge, 2.00 m so that this scouring could affect the stability of the bridge and potentially collapse the bridge based on simulation with flood discharge plan 25 years.