Recent Applications of the ASI-Gauss Code on Structural Collapse and Motion Analysis


Catastrophic disasters of large-scale framed structures occurred recently are mainly caused by sudden, extreme external loads such as aircraft collision, explosion, large seismic excitation, big fire, and etc. Dynamic codes are generally used to investigate such phenomena. However, strong nonlinearity in the deformation of structures and rapidness of the external loads often generate higher hurdle in the analyses. The authors have developed an adaptive finite element code with the use of an ASI (Adaptively Shifted Integration)-Gauss technique, which provides higher computational efficiency than the conventional code in such analyses, and enable us to cope with dynamic behavior with strong nonlinearities including phenomena such as member fracture and elemental contact. One of the recent applications of the numerical code is a continuous analysis of a steel frame building subjected under a seismic excitation followed by an input of the drag force and buoyant force due to tsunami wave, and finally, collided with a debris. With a particular structural condition of the building with no walls under water, the building withstands the tsunami force as well as the impact force driven by the debris collision. The numerical code is also applied to a ceiling collapse analysis of a gymnasium under seismic excitation. It is very important, nowadays, to know the collapse mechanism of the ceilings since it causes not only the possibility of human injuries, but may disturb the use of the facilities after earthquakes. The behaviors of plaster boards near walls and roof top, which drop occasionally due to detachment of clips and screws, are well simulated.The other numerical cases include a motion analysis of furniture under seismic excitation. A sophisticated penalty method is applied, in this case, to realize the slip and contact motions of furniture with and without casters. The tumbling motions of furniture are well simulated as a whole in spite of different seismic waves.