A microcomputer-based software system DSBT (dynamic solver for reinfor
ced concrete box tubes) is developed. The program is coded in C and ca
n be conveniently executed on a personal computer. The theoretical bac
kground for this program includes three parts: (1) the truss model the
ory for the primary curves of box tubes, (2) the analytical model of t
he hysteresis loops, which describes the behavior of the box tubes und
er repeated loading and unloading, and (3) the dynamic model used for
dynamic analysis. The combination and implementation of these three co
mponents forms a useful tool for the dynamic analysis of such box tube
s. Using this tool, three examples are analyzed: a box tube under stat
ic torsion, a one-storey box tube and an eight-storey box tube subject
ed to dynamic torsion.