Stress Variation Mechanism and Monitoring Methods for Large-Span Steel Structure Unloading Process

During the unloading process of the large-span steel structure, the boundary conditions of the structure could be different with the design model due to reasons such as asynchronous unloading process, inconsistent location of temporarily supporting points, while the structural stresses during the unloading process and those analysis results in structural design are different. Hence, it is necessary to carry out the research on stress variation mechanism as well as monitoring methods on the dynamic unloading process, which could feedback on structural design and construction to ensure safety. In this paper, the structural health monitored data collected by the construction monitoring system of Shenzhen Sports Center is used to study the stress variation and redistribution mechanism during the dynamic unloading process of the large-span steel roof. Combining the finite element stress analysis and monitored stress data, the stress redistribution process is detailed described and its underlying mechanical mechanism is revealed. Based on the stress variation process and mechanism the key components and vital process of the unloading process are determined to help study the stress monitoring methods. The stress monitoring methods of large-span steel structure unloading process contains the layout of stress sensors, exclude other factors’ effects such as asynchronous unloading process and collecting real-time stress data. The stress monitoring methods would provide effective technical support for steel structure construction to avoid safety accident. The stress variation mechanism during large-span steel structures could provide supports for other steel structure construction. The stress monitoring methods accumulated in this paper also provide the measurement basis and effective technologies for the unloading of similar structures.