Prototype impact tests on ultimate impact resistance of PC rock-sheds

To confirm the ultimate impact-resistant capacity of Prestressed Concrete (PC) rock-sheds constructed over the highways in Japan, prototype impact tests are conducted by using two types of PC rock-shed frames: inverted L frame and fully rigid frame. The two types are of equal dimensions: span length=10.1 m, upper flange width=150 cm, column height=4.65 m. The impact tests are performed by iteratively and freely dropping a 3000/5000 kg steel weight onto the center of each frame covered with a 90 cm thick sand cushion. The results obtained from this study are as follows: (1) the fully rigid frame has more than 1.7 times the impact-resistant capacity of the inverted L frame with reference to input impact energy; (2) the fully rigid frame can effectively disperse the sectional forces over the whole structure; (3) the inverted L frame and fully rigid frame PC rock-sheds designed based on allowable stress design procedure have more than three and five times the margin against collapse, respectively.