Behavior of Steel Moment Frames Using Top-and-Seat Angle Connections under Various Column-Removal Scenarios

Qian, Kai; Lan, Xi; Li, Zhi; Fu, Feng

doi:10.1061/(asce)st.1943-541x.0003089

Cited by 15 publications

(3 citation statements)

References 55 publications

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“…It is simply assumed that each story has identical geometric and material properties and thus, assuming each story performed identically. However, as pointed out by Qian et al (2020), Qian et al (2021b), andWeng et al (2020), the load resistance of the beams in the first story is quite different to the second and upper stories. It could be explained that the interaction among different stories, which leads to different mobilization of load resisting mechanisms (flexural and catenary action).…”

Section: Introductionmentioning

confidence: 92%

Effects of Steel Braces on Robustness of Steel Frames against Progressive Collapse

Qian

Lan

et al. 2021

J. Struct. Eng.

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External installation of steel braces is one of the effective approaches to increase the lateral load resistance of the steel moment-resisting frames. However, the effects of existence of steel braces on the robustness of steel moment-resisting frames to resist progressive collapse is still not clear as little study has been carried out. To fill this gap, in this paper, six multi-story steel moment-resisting subframes (three bare frames and three braced frames) were fabricated and tested. Test results indicated that the specimen with reduced beam section in the connection zone performed best among three types of connections, due to the guaranteed formation of plastic hinges at the location of reduced section and avoiding brittle fracture of weld at the connection. Experimental results proved that steel braces could increase the load resisting capacity by 45.1% and 83.9% of the frame with weld connection and end plate connection, respectively. As the gusset plate restricted the rotation of the plastic hinges in the second story of the braced frames with V-shaped bracing, which decreased its deformation capacity and degraded its catenary action capacity. Actually, the ultimate load of the braced frames with Vshaped bracing is only 87.5% of that of the counterpart without any braces. As the compressive braces were severe buckled before the displacement reached 0.4% of the beam span, it has little effects on yield load but increases the initial stiffness of the bare frames. Thus, majority of the benefits of the bracing system were attributed into the tensile braces. Moreover, the analytical results evaluated the differences in load resistance and development of load resisting mechanisms in different stories.Furthermore, the contribution of compressive and tensile braces was de-composed individually by analytical analysis.

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Section: Introductionmentioning

confidence: 92%

Effects of Steel Braces on Robustness of Steel Frames against Progressive Collapse

Qian

Lan

et al. 2021

J. Struct. Eng.

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“…Comparison of the collapse resistance between single-story frames and multi-story frames revealed that the collapse resistance between two different structural scale models is not based on the number of stories because of the existence of Vierendeel action (VA) [16][17][18]. Qian et al [19][20], Tsito et al [21] and Zhong et al [22] have conducted quasi-static collapse tests, and subsequently, compared and analyzed in detail the influence of connection type, failure column position, and other parameters on the structural performance. Their results show that the connection types and failure column position exhibit a considerable influence on the exertion of catenary action.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of Effect of Various Span-to-Depth Ratios on the Collapse Performance of Planar Steel Frames

2022

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After the removal of a column caused by the unexpected extreme loading of the building structure, the remaining structure mainly relies on the double-span beams connected with the failed column to mitigate the progressive collapse, therefore, the span-to-depth ratios of the double-span beams has significant effects on the internal force redistribution among each story and the development of the anti-collapse mechanisms of the multi-story planar frames. To investigate the effect of span-to-depth ratios on the progressive collapse performance of steel frames, the collapse analysis of three-story steel frame models with various beam depths and beam spans was numerically studied. Firstly, the correctness of the numerical modeling method was verified by the collapse test results of a two-story sub-frame. Then, the refined modeling methods were applied to the analysis of progressive collapse performance of steel frames with various span-to-depth ratios. The load response, load distribution, deformation characteristic and load-resisting mechanisms of models are investigated in detail. The results showed that the resistances provided by flexural mechanism and catenary mechanism are mainly determined by span-to depth ratios and beam span, respectively. Through the principle of energy conservation, the different resistant contribution coefficients of each story are quantitatively obtained, and corresponding empirical formulas were proposed, which can be used as a reference for resistance evaluation before the design of structural anti-collapse.

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“…The research on the progressive collapse resistance of structures has been a hot topic worldwide for many years due to the partial or total collapse of iconic and public buildings [1][2][3][4][5][6][7][8]. There are numerous studies about the progressive collapse behavior of reinforced concrete [9][10][11][12][13] and steel frame structures [14][15][16][17]. The collapses of long-span spatial structures, especially for the spatial truss structures caused by member failure, may lead to more losses.…”

Section: Introductionmentioning

confidence: 99%

Robustness Analysis and Important Element Evaluation Method of Truss Structures

Feng

Sun

et al. 2021

Buildings

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Robustness and vulnerability are important evaluation criteria for structural safety to improve progressive collapse resistance. Modeling rapid evaluation on important elements in the conceptual analysis stage is an essential and efficient way to ensure the robustness of a design. This paper proposes an evaluation method for element importance by using structural strain energy, which can reflect the influence of geometric topology and external load distribution on the structural safety status simultaneously. Three simple planar trusses are chosen to clarify the proposed method. Moreover, the influences of geometric topology, boundary condition, stiffness distribution and load distribution on the element importance are investigated. This evaluation method also extends to the two spatial truss structures, regular quadrangular pyramid grid structures and chessboard-shaped pyramid grid structures. The distribution characteristics of important elements are obtained. This work defines the element importance distribution law of typical structures. It provides a method for rapid robustness analysis of general truss structures, which can be effectively integrated into the existing analysis platform.

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Behavior of Steel Moment Frames Using Top-and-Seat Angle Connections under Various Column-Removal Scenarios

Abstract: Behavior of Steel Moment Frames using Top-and-Seat Angle Connections under Various Column Removal Scenarios.

Cited by 15 publications

References 55 publications

Effects of Steel Braces on Robustness of Steel Frames against Progressive Collapse

Effects of Steel Braces on Robustness of Steel Frames against Progressive Collapse

Quantitative Evaluation of Effect of Various Span-to-Depth Ratios on the Collapse Performance of Planar Steel Frames

Robustness Analysis and Important Element Evaluation Method of Truss Structures

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