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A theoretical study is made of the dynamic behavior and the permanent deformationsof a rigid-perfectly plastic beam under impact loading. The beam is simply supported andthe load is distributed along some portion of the beam axis. Bending and shearing de-formations are analysed on the basis of a simplified interaction curve relating shearingforce and bending moment for fully plastic action. The analysis shows that the sheareffects are of considerable importance when the loading width is approximately less thanone half of the whole span.

For the large roofs of sub-gates for EXPO'70, a prestressed suspended roof was adopted.Two types of model tests were conducted to obtain informations for the design of the structure:wind tunnel tests to know the nature of wind loading, and static loading tests to know the staticperformance.Wind tunnel tests were carried out on 1/100 scale models of plastics and rubber sheets.Wind pre3sure distributions on roof surfaces were obtained for nine cases of horizontal and verticalwsnd directions. Dynamic behaviors of roof membranes in wind were observed and someresults were obtained.Also a cable model, which had a scale of 1/15, was tested statically, making use of the windtunnel test results. Data were obtained for the determination of the initial prestressing forcedistribution, the situation of the change in cable tensions under load, and the deflections of theroofs.A numerical calculation was made on the above mentioned problems. The result from theanalysis is compared with the test result and a brief discussion is made.

An experimental study is made on the nature of the large permanent deformation of the columns in a portal frame under horizontal impact loading. The column specimens were made of mild steel, aluminum alloy and copper plates. The impact load was applied by an input pendulum. The applied load and initial velocity were measured by the barium titanate ceramics, accelerometer and load cell which had been calibrated beforehand from the initial amplitude of a bifilar pendulum. The experimental results show a reasonable consensus with the analysis in which the frame restoring-force characteristics are approximated as bi-linear with a negative second slope.

An experimental study is made of large permanent deformation of the columns in a portalframe under horizontal impact loading. The column specimens are made of mild steel, alu-mmum alloy and copper plates. The impact load is applied, by means of a bifilar pendulum, as a large acceleration for a short period. The applied initial velocity at the base of columns ismeasured by the accelerometer, which was calibrated beforehand from load cell readings. Theexperimental results show a general consensus with the analysis which approximates the framerestoring-force characteristies to be hi-linear with a positive slope followed by a negative.