DEVELOPMENT OF PRACTICAL MEASUREMENT EQUIPMENT OF MEMBRANE STRESS FOR MEMBRANE STRUCTURES

Abstract

One of the most important matters in keeping membrane structures in healthy condition is to maintain the proper tension distribution over the membrane. However, it is not easy to know the real stress level in the membrane quantitatively after completion of the structures. The authors proposed a new method that can measure membrane stresses in two different directions separately using sound waves –instead of measuring the membrane stresses directly. In this paper, various problems in the downsizing of measurement equipment and reduction of measurement time for practical application are examined, and clarified both theoretically and experimentally. In addition, not only the experimental tests using the membrane material of PTFE coated glass fabric as well as ETFE film with various combinations of the membrane stress, but also the actual measurement for existing suspension structure covered with ETFE film is carried out for practical use. The results verify the developed equipment can be used to continue measurement as a tool for scientifically and quantitatively determining the membrane stress which exists in the membrane material of the actual membrane structures.