2020 Vol. 35, No. 1

Display Method:
Research Progress on Cold-Formed Steel Structural Framing
Xuhong Zhou
2020, 35(1): 1-19. doi: 10.13206/j.gjgSE20010804
Abstract:
Cold-formed steel (CFS) structural framing system widely used in North America and Europe is also applicable in China due to low weight, high strength, environmental friendliness, and fast fabrication. In the last three decades, numerous researches have been carried out to investigate the structural performance of CFS framing buildings. The author started to study the CFS structures in the 1980s and is one of the earliest advocators of applying CFS structures in residential buildings. This paper summarizes the research progress on CFS framing buildings, including local buckling and distortional buckling of CFS columns, compression and flexural behavior of build-up columns and beams, diaphragms, vibration performance of composite floor systems, strength and stiffness of shear walls, the seismic behavior of whole CFS structure, and the fire resistance of build-up columns. Lastly, future research for advancing the knowledge relating to structural behavior of CFS structures is suggested.
Application of Steel-Concrete Composite Structure in Ocean Engineering
Jianguo Nie
2020, 35(1): 20-33. doi: 10.13206/j.gjgSE19112601
Abstract:
Ocean engineering and construction are promising foundations for the implementation of China’s maritime power strategy. Compared to land engineering, ocean engineering requires more complex and demanding construction environments and conditions, which pose new challenges to structural engineering. Steel-concrete composite structures have broad application prospects in ocean engineering with significant performance advantages and comprehensive economic benefits as they successfully combine the respective advantages of steel and concrete. This paper summarizes the research work of composite structure research team of Tsinghua University with respect to the development and application of three types of composite structures in ocean engineering: cross-sea bridges, submarine immersed tunnels, and floating offshore platforms. Four new structural systems are proposed, including a long-span continuous beam bridge with integrated anti-crack technology, a double-steel-plate-concrete composite bridge tower suitable for cross-sea multi-tower cable-stayed bridges, a compartment steel-concrete-steel composite structure suitable for submarine immersed tunnels, and steel-concrete composite very large floating structure (VLFS).The key load-transferring mechanisms, mechanical performance, and design methods of the new structures are studied in depth, which are applied to the design of large-scale engineering projects such as the Dalian Bay Bridge, Nanjing No.5 Yangtze River Bridge, Shenzhen-Zhongshan Link, and offshore VLFS.Research and practice demonstrate that the new composite structural system has significant performance advantages and achieves satisfactory comprehensive economic benefits, thus providing new ideas and choices for ocean engineering construction and effectively promoting the application of steel-concrete composite structures in ocean engineering.
Historical and Technological Developments of Steel Bridges in Japan—A Review
Yozo Fujino, Dionysius Siringoringo
2020, 35(1): 34-58. doi: 10.13206/j.gjgSE19112604
Abstract:
This paper describes a historical review of steel bridge in Japan and its associated technological developments. The review is based on four basic technologies: structural analysis technology, material technology, structural design technology, measurement and maintenance technology. Steel production and welding technologies have progressed remarkably since the 1950s, and this influence the use of steel as material for bridges in Japan. As a result, materials, analysis and design technologies related to the steel bridge have progressed rapidly. The paper describes landmark technological development and constructed steel bridge in each era from late 1800s to year 2000s. Progress in production of higher quality of steel material and better understanding of mechanical aspect for safety and serviceability of steel structure from research and development are followed by updating design guidelines in an effort to standardize the use of higher quality and performance of steel material for bridge structures.
Review of the Promotion and Application of Steel Structures in Construction
Yinquan Yu, Fengqi Zhu, Zhe Wang
2020, 35(1): 59-69. doi: 10.13206/j.gjgSE19112602
Abstract:
In China, steel structures have broad applications and good development prospects. This paper summarizes the development status of steel structures, analyzes the characteristics and market advantages, and introduces the authors’ work regarding the promotion and application of steel structures. The conclusions are as follows. There have already been a series of policies to encourage the development of assembled steel structures issued by state and local governments in recent years. By developing steel structures, the problems of overcapacity in the Chinese steel industry can be solved. Steel structures have many advantages, such as exhibiting superior performance, better meeting the demands of construction and providing a high degree of industrialization and environmentally friendly materials. These advantages are particularly critical in high-rise buildings, large space facilities, commercial facilities, factories and warehouses, integrated sets of equipment structures and other construction fields. Steel structures also have better comprehensive economic and social benefits, which account for an approximately 5%~10% difference in the total investment of a project compared with that of concrete structures. The compilation and revision of standards guide the process of design, which is an important contribution to the promotion of steel structures.
Experimental Investigation on Damage Identification of Cable-Stayed Arch-Truss Structures Using Modal Parameters
Bin Zeng, Zhen Zhou, Qing Xu, Qingfang Zhang, and Jun Zhao
2020, 35(1): 70-84. doi: 10.13206/j.gjgSE19112603
Abstract:
In this paper, the experimental research on the damage identification method based on modal parameters for the cable-stayed arch-truss was conducted. Two test models of 6 m-span cable-stayed arch-truss were designed and fabricated. The structural damage was simulated by replacing the normal members with struts of different cross sections. Different damage conditions such as damage of the arch-truss members and the damage of the cable-strut system were designed. The modal parameters of first three orders were obtained through dynamic test for each damage condition, and the test results were analyzed by the combined identification method which was based on the vibration modal parameters: the top arch-truss was diagnosed by curvature modal difference method and modal flexibility difference curvature method. The regularized frequency change rate method is used to diagnose the bottom cable-strut system. The damage identification test results show that the curvature modal difference method and the modal flexibility difference curvature method have better effect on the damage identification of single-damage and multiple-damage of the cable-stayed arch-truss. And the recognition effect of the upper chord is better than that of the lower chord. Compared with the curvature modal difference method, the mutation of non-damage position is smaller and interference items are less by using the modal flexibility difference curvature method, leading to a better recognition effect; the regularized frequency change rate index of the first three orders’ frequency can effectively identify whether the cable support system is damaged. However, damage positioning for symmetrical position needs further verification.