Seismic effect on the fire performance of wooden walls designed for low rise buildings

This report presents a review of the experimental studies on the seismic effect on the fire performance of wooden walls of the post & beam construction, 2×4(platform) construction, prefabricated wooden panel construction and traditional soil-wall construction conducted through various Japanese R&D programs during the last two decades. The specimens are designed basically to satisfy the requirements for Quasi-fireproof construction, required for buildings larger than 500m² in urban districts, for every new construction in densely inhabited districts in large cities and for 3 story public buildings in every district. Most of the studies are based on loaded fire resistance tests and compare these performances between the specimens with and without horizontal shear test prior to the furnace test. Distortion angles are decided by referring to the typical condition for the seismic design of wooden low-rise dwelling buildings. Among the elementary fire performances of external walls, the mechanical integrity is found to be the key dominating the fire performance of all the experiments. The experiments suggest reduction of fire endurance time by 20% or less by the "design" distortion angle. Recent studies on the traditional timber frame and soil-wall constructions suggest potential capability of soil walls to maintain suitable fire resistance even after a big earthquake if the wall is designed to meet Quasi-fireproof construction.