Behaviour of industrialised building system model in fluid-solid interaction

Abstract

The IBS block-work building system is the invention of a Universiti Teknologi Malaysia researcher. The system is targeted towards resisting earthquakes of up to 10 points on the Richter scale. During a recent tsunami after earthquakes, many reinforced concrete buildings that were engineered to resist earthquakes damaged due to the unexpected magnitude of the tsunami’s forces. Currently, there is significant disagreement on existing empirical formulae for the calculation of tsunami-induced force components. In this research, a 1:5 scale IBS model was developed, according to the Buckingham Pi Theorem and Similitude Theory. The behaviour of the 1:5 scale IBS model, when subjected to tsunami bore of ranges from 0.3 m to 1.2 m bore height and debris impact, was investigated experimentally and through dynamic nonlinear finite element analysis. The tsunami bore was simulated in a laboratory by performing a dam break test. Interactions between simulated tsunami bores and the IBS model were investigated experimentally by measuring bore-depth variations, bore velocity, force exerted on the structural models and variations of pressure on the upstream-face of the structure. The structure was assessed based on different performance levels of Operational, Immediate Occupancy, Life Safety and Collapse Prevention, according to FEMA 356. An increase in the impounding water depth led to an increase in the maximum inundation depth downstream at the location of the IBS model, and a proportional increase in the bore front velocity. The hydrostatic pressure distribution of bore impact on the structure was observed throughout the fluid-structure interaction. The impulsive and hydrodynamic forces, obtained from the experimental data, were in agreement with the Japan Cabinet Office guideline (2005) (SMBRT) and the Coastal Construction Manual (FEMA P-55), respectively. From the experimental and numerical study, the IBS structure showed an Operational Performance during tsunami bore, ranging from 0.3 m to 0.6 m height. The scaled structure had an Immediate Occupancy performance level up to 0.9m water bore height. The Life Safety performance level for the IBS structure was 1.2m tsunami bore height (equivalent to 6 metres in the real world). During the debris impact, the IBS column performed very well when impacted by a family car size and wooden log debris. Therefore, the obtained results indicate that this type of IBS model is safe to resist the tsunami.