Optimization of Gridshells Against Instability Considering Joints’ Mechanical Performance

This open access book introduces external factors such as loads and constraints into the theory of configurational vulnerability, thereby overcoming the classical theory's inability to account for external influences. Stability is a governing factor in the design of single-layer gridshells, becoming increasingly critical as the span grows. However, current design methodologies address stability primarily through post-design verification, which severs the intrinsic link between member design and overall structural stability. This disjointed approach leads to iterative cycles of design and verification, reducing efficiency. Concurrently, advances in industrialized construction have spurred the development of numerous innovative joints tailored for prefabricated construction. These joints are neither ideally rigid nor ideally hinged. Yet, prevailing design methods and stability verification processes still assume ideal rigid connections, failing to incorporate the mechanical properties of joints and thereby constraining the adoption and application of these new designs. This integration provides a novel perspective on instability mechanisms. Based on the instability mechanisms of gridshells, a stability optimization model is developed under the rigid joint assumption. Due to the large number of variables involved in the optimization model, conventional algorithms often prove inadequate. To address this, the study enhances the standard genetic algorithm by replacing its random mutation mechanism with a directed mutation mechanism, significantly improving search efficiency. The improved algorithm efficiently solves large-scale stability optimization problems for single-layer gridshells, as validated using three gridshells of varying scales and two constructed examples. To expand the forms of gridshell joints, the study employs advanced topology optimization techniques to enhance rotational stiffness. Simultaneously, the study integrates the requirements of prefabricated construction by designing a universal connection interface capable of accommodating members from diverse orientations. This effort culminates in the development of novel joint designs for spatial grid structures that are both mechanically efficient and construction-friendly. 

Table of Contents:
1. Introduction.- 2. The stability mechanism of single-layer gridshells based on the theory of configuration vulnerability.- 3. Stability Optimization of Single-layer Lattice Shell Structure Based on Rigid Joints.- 4 Stability Optimization and Collapse Resistance Verification of Large Single-layer Lattice Shell Structure.- 5. Topology Optimization Design of Joints of Single-Layer Gridshells.- 6. Optimization of Stability of Single-Layer Gridshells Considering Joint Stiffness.- 7 Conclusion and Prospects.

About the Author :
Lu Mingfei, born in 1991, is a senior engineer with a master's and doctorate from the School of Civil Engineering at Southeast University. He specializes in spatial structures and underground space development. Currently, he is a senior researcher at the Underground Space Science Research Institute of CCCC First Highway Engineering Group and a postdoctoral fellow at CUMT/CCCC First Highway Engineering Group. He has published over 10 papers, including 6 indexed by SCI/EI, holds 3 software copyrights, and owns 11 invention patents. He has participated in 3 national projects, led 2 provincial-level projects, and was selected for the CCCC Young Talent Support Program. Ye Jihong, female, of Han ethnicity, was born in January 1967 in Meixian, Guangdong Province. She is a member of the Communist Party of China, a professor, and a doctoral supervisor. She currently serves as a member of the Standing Committee of the Party Committee and Vice President of China University of Mining and Technology. Her academic and research work focuses on fire resistance, seismic performance, and wind resistance of long-span spatial structures and light steel structures. She has led a number of major national research projects, including a National Natural Science Foundation (NSFC) Major Research Instrumentation Project, an NSFC Key Project, a Major Research Plan of the NSFC, and a subproject of the National Science and Technology Support Program. She is the chief editor of one provincial-level engineering construction standard. Li Hui, Deputy Director of the Institute of Underground Space Science at CCCC Tunnel Engineering Bureau, holds the title of Senior Engineer. He has long been deeply engaged in the technical management of urban rail transit and super-large diameter shield tunneling. Over the years, he has participated in numerous major tunneling projects, including the Weisan Road Yangtze River Crossing in Nanjing, Beijing Metro Line 8, and Tianjin Metro Line 11. He has taken a leading role in coordinating technical management and scientific research efforts in rail transit, super-large diameter shield tunneling, and underground engineering. Notably, he has been extensively involved in technical planning, support, knowledge accumulation, and standardization for several key super-large diameter shield projects, such as the Nanjing Heyan Road Tunnel, Beijing East Sixth Ring Road Reconstruction Project, Shanghai Airport Link Line, and the Jiangyin-Jingjiang Yangtze River Tunnel.