Seismic behavior of steel frames with replaceable reinforced concrete wall panels

Hanheng Wu,Tianhua Zhou,Fangfang Liao,Jing Lv 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.5

The paper presents an innovative steel moment frame with the replaceable reinforced concrete wall panel (SRW) structural system, in which the replaceable concrete wall can play a role to increase the overall lateral stiffness of the frame system. Two full scale specimens composed of the steel frames and the replaceable reinforced concrete wall panels were tested under the cyclic horizontal load. The failure mode, load-displacement response, deformability, and the energy dissipation capacity of SRW specimens were investigated. Test results show that the two-stage failure mode is characterized by the sequential failure process of the replaceable RC wall panel and the steel moment frame. It can be found that the replaceable RC wall panels damage at the lateral drift ratio greater than 0.5%. After the replacement of a new RC wall panel, the new specimen maintained the similar capacity of resisting lateral load as the previous one. The decrease of the bearing capacity was presented between the two stages because of the connection failure on the top of the replaceable RC wall panel. With the increase of the lateral drift, the percentage of the lateral force and the overturning moment resisted by the wall panel decreased for the reason of the reduction of its lateral stiffness. After the failure of the wall panel, the steel moment frame shared almost all the lateral force and the overturning moment.

Application of self-centering wall panel with replaceable energy dissipation devices in steel frames

Sisi Chao,Hanheng Wu,Tianhua Zhou,Tao Guo,Chenglong Wang 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.2

The self-centering capacity and energy dissipation performance have been recognized critically for increasing the seismic performance of structures. This paper presents an innovative steel moment frame with self-centering steel reinforced concrete (SRC) wall panel incorporating replaceable energy dissipation devices (SF-SCWD). The self-centering mechanism and energy dissipation mechanism of the structure were validated by cyclic tests. The earthquake resilience of wall panel has the ability to limit structural damage and residual drift, while the energy dissipation devices located at wall toes are used to dissipate energy and reduce the seismic response. The oriented post-tensioned strands provide additional overturning force resistance and help to reduce residual drift. The main parameters were studied by numerical analysis to understand the complex structural behavior of this new system, such as initial stress of post-tensioning strands, yield strength of damper plates and height-width ratio of the wall panel. The static push-over analysis was conducted to investigate the failure process of the SF-SCWD. Moreover, nonlinear time history analysis of the 6-story frame was carried out, which confirmed the availability of the proposed structures in permanent drift mitigation.

Cyclic response of self-centering SRC walls with frame beams as boundary

Lu Sui,Hanheng Wu,Penghui Tang,Tao Gong,Yifan Wang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.1

In recent years, earthquake resilient structures have become a research focus in the field of seismic engineering. In order to improve the resilience of steel frame - concrete wall panel structures, an innovative self-centering SRC wall panels with replaceable energy dissipaters is presented in the paper. For this purpose, the tested subassembly involving the self-centering SRC walls with frame beams as boundary was presented. The wall panels used in steel moment frames can provide the lateral resistance for structures. Test models of the wall panels with partial framed beams as boundary were suggested. The full-scale specimens were tested under cyclic lateral loads. The configuration of energy dissipaters and initial force of PT steel bars were varied to study their impacts on lateral behavior of the walls. Furthermore, the numerical models based on ABAQUS were developed. The parameter studies, including diameter of PT tendons, beam profile, beam span and wall width, were then conducted. The PT tendons can provide self-centering ability and the dampers are used to dissipate energy. The failure of the wall panels is mainly concentrated on energy dissipaters. This case makes it possible to repair the walls easily.

Shearing Bearing Capacity of Screwed Connections of Thin Steel Sheets

Sisi Chao,Linfeng Lu,Hanheng Wu 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.2

This paper reviews the design rules of single shear screwed connection of cold-formed steel structure in the current design specifi cations, such as North American, Australian/New Zealand, European, British, Japanese and Chinese, and points the shortcomings of Chinese design specifi cation and the mistakes of some published reports on the shear resistance of single shear screwed connections. A total of 194 single screw overlap sheared connections, which were made of steel sheet manufactured in China and were tested by Chinese scholars since 1993, and the detailed test data are introduced. Using the design specifi cations mentioned above recalculated the normal connection shear strength of the 194 connection specimens, and evaluated the accuracy of six design specifi cations under the diff erent failure modes. The Japanese design manual is too conservative to estimate the bearing capacity of the single shear screwed connection under any failure mode. For tilting or tilting and bearing failure mode, the accuracy of the AISI S100 and AS/NZS 4600 diminishes and sometimes tends to be unsafe; however, the Eurocode 3, BS5950-5 and GB50018 are appropriate. As to screw shear failure mode, the AISI S100, AS/NZS 4600, Eurocode 3 and BS5950-5 are appropriate but GB50018 tends to be unsafe. The paper gives a new design formula as a supplement to GB50018 that can accurately predict the bearing capacity of single shear screwed connection in all failure modes. Finally, the Group Eff ect of multiple-screw shear connection was investigated based on 38 multiple-screw connection specimens.

Compressive behavior of built-up open–section columns consisting of four cold-formed steel channels

Shaofeng Nie,Cunqing Zhao,Zhe Liu,Yong Han,Tianhua Zhou,Hanheng Wu 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.6

Compression experiments were conducted to investigate the compressive behavior of built-up open-section columns consisting of four cold-formed steel channels (BOCCFSs) of different lengths, thicknesses, and cross-section sizes (OB90 and OB140). The load-displacement curves, failure modes, and maximum compression strength values were analyzed in detail. The tests showed that the failure modes of the OB90 specimens transformed from a large deformation concentration induced by local buckling to flexural buckling with the increase in the slenderness ratio. The failure modes of all OB140 specimens were deformation concentration, except for one long specimen, whose failure mode was flexural buckling. When the slenderness ratios of the specimens were less than 55, the failure modes were controlled by local buckling. Finite element models were built using ABAQUS software and validated to further analyze the mechanical behavior of the BOCCFSs. A parametric study was conducted and used to explore a wide design space. The numerical analysis results showed that when the screw spacing was between 150 mm and 450 mm, the difference in the maximum compression strength values of the specimens was less than 4%. The applicability and effectiveness of the design methods in Chinese GB50018-2002 and AISI-S100-2016 for calculating the compression strength values of the BOCCFSs were evaluated. The prediction methods based on the assumptions produced predictions of the strength that were between 33% to 10% conservative as compared to the tests and the finite element analysis.