Structural durability assessment of stilt houses to flash flooding: Case study of flash flood-affected sites in Thailand

The ‘stilt house’ is found in many flood-prone areas and represents local wisdom regarding building construction to coexist with floodwaters. Most academic research projects have studied stilt houses based on two types of flood: inundation and coastal flooding. The study of pillar houses in flash floods is very limited. This research investigated whether the main structure of a stilt house could withstand strong water current to determine the suitability of the stilt house for flash flood sites. The study explored the physical appearance of stilt houses in five flash flood areas in Thailand. The styles of stilt houses in each area were simplified to generate models and to then test their tolerance toward moving water. The main findings were: 1) the main structure of the stilt house can resist flood loads at 1.00 m depth with a waterflow speed at 3.05 m/s; 2) the most vulnerable points on the main structure if struck by more rapid, deeper flows of water are the base of the column and the joint between the column and beams; and 3) the horizontal or diagonal bracing members perpendicular to the flow and not above the flood level become water blockades that increase the reactive force to the main structure.