A study is made of the behaviour of steel beams subjected transverse impact loading, with the general aim of developing a design method for collision resistant structure of nuclear powered ships. The effect of axial forces of the beam at large deflections are taken into account. The particular problem investigated comprehensively, both theoretically and experimentally, is the light gauge steel section clamped at the ends and subjected to concentrated normal load at the middle of the span. The load is given statically (by oil jack) and dynamically (by 800kg-m impact tester), and both results are compared. The analysis of the behaviour of the beam is given excellent suport by the results of the experimental work, which also suggests the optimum design of collision resistant structure. On the basis of the investigation herein, simple formulae are presented which can be used to obtain the practical load-carring capacity of beam.