Effective techniques for assessing the safety of building structures with the emphasis on lift ropes and pipes

Safety and maintenance of building structures have become a prime concern as there are millions of buildings in China. Lifts and pipes are crucial infrastructure integrated in most of building. Ropes are used to hoist or support lifts. Pipes are used to transfer water or gas to each household unit of a building. In modern cities, natural gas is a major fuel source for heating and cooking. Gas pipe risers are used to distribute natural gas to each household unit in buildings. These gas risers are erected along the external wall of the buildings and penetrated into each household unit through the concrete wall of the buildings. According to the recent statistic figures provided by the Towngas in Hong Kong, there are over 12.93 million and 1.75 million household units that have such gas risers in Mainland and Hong Kong, respectively. Both pipes and ropes are prone to defects due to their aging and suffering from external impacts during operation. For instance, suddenly broken ropes can cause their hoisted lifts plunge to the ground, resulting in human casualties. Severe damage in natural gas pipes could cause pollution to the environment, huge economic losses, and even become hazardous to human lives. Therefore, there is a crucial need to develop effective methods for ensuring the safety and proper maintenance of lift ropes and pipes in buildings. This paper presents advanced and effective techniques, which include ultrasonic guided waves, active thermography and other non-destructive evaluation means for inspecting the safety of lift ropes and building pipes. The problems and difficulties involved in inspecting ropes and pipes in buildings are discussed. A number of experiments are used to demonstrate the effectiveness of these techniques. With the help of these advanced techniques, the buildings are safer to live in with less frequency in service breakdown and reduced chance that catastrophe may occur because of the sudden failure of ropes and rupture of pipes.