Abstract
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.