by: Prof. Ir. Djoko Legono, Ph.D.
MTPBA student batch XVI/August 2016
Department of Civil and Environmental Engineering conducted a visit to Bantul to observe the flood location at Opak river. Previously, there is no flood ever happened in Opak area. This disaster is triggered by the Cempaka cyclone that was recently happened.
Observations and visits were focused on Nambangan bridge and Soka bridge in Pundong, Bantul that suffered from the most damage. The Nambangan bridge collapsed because of heavy river flow to 18 meters above the riverbed. The plantations on the riverbank is also damage. The very high capacity of waterflow touched the embankment. There is a landslide on the river banks due to the water flow.
The observation also includes changes in soil structure of Opak river banks. The soil texture is still soft because of the water content in the soil. The remaining parts of the bridge that are still visible i.e. the two standing poles and several collapsed poles. Nambangan bridge has 70m length with its precast floor plate bridge floor structure. Each precast floor has a length of 10m and a width of 1 m.