Abstract
Many concrete structures have been built half a century ago in Japan. Those service lives are going to pass. So development of efficient and economical testing methods is desired. Climbing testing machine is one of the methods. It doesn't need scaffoldings so it is efficient and economic. Concrete-wall climbing machines generally use suction cups to hold their body. However, climbing testing machines have dangerousness of falling down. The causes of the falling down are inadequate decompression of the suction cups and slip between the suction cups and concrete wall. The inadequate decompression can be avoided by moving the suction cup. We had developed suction cups preventing slip on concrete wall by using claws. Claws are equipped on the suction cups and get the wall tightly. In this paper, scratch test of a claw on concrete plates, concrete blocks and red bricks have been done to get the maximum holding force of the suction cups. According to the results, the method to determine dimensions and pressure of suctions was discussed.
