scholarly journals Retrofit Strategies against Progressive Collapse of Steel Gravity Frames

2020 ◽  
Vol 10 (13) ◽  
pp. 4600 ◽  
Author(s):  
Lei Zhang ◽  
Honghao Li ◽  
Wei Wang

Two retrofit strategies, aiming at increasing the collapse resistance of simple connections by adding seat angles and steel plates with long-slotted holes, are proposed in order to address the vulnerability of steel gravity frames under column loss scenarios. A high-fidelity, detailed, finite element model for a planar composite frame is developed and calibrated against experimental data and is used to conduct numerical analysis to explore the effectiveness of the proposed retrofit strategies. The simulation results show that the planar composite frame with enhanced connections exhibits significantly higher collapse resistance and better ductility under column loss scenarios compared with the one with conventional connections. Meanwhile, it is also revealed that the proposed retrofit strategies have an insignificant impact on the behavior of the structural system under earthquakes. These two retrofit strategies are then implemented to retrofit the gravity system of a 10-story, seismically designed steel frame structure, which has been shown to be vulnerable to progressive collapse after an interior gravity column is forcibly removed or impacted by a heavy vehicle with high speed. Numerical simulations were performed using a 3-D micro-based model and the simulation results illustrate that progressive collapse of the structure with enhanced gravity systems is prevented under both scenarios. Therefore, the proposed retrofit strategies are effective in preventing the progressive collapse of existing steel structures employing simple connections.

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Youquan Liu ◽  
Jingang Xiong ◽  
Jiancong Wen

Progressive collapse behavior of case-in-place concrete and steel frame structures has been extensively investigated over the past years. However, studies on progressive collapse resistance and characteristics of prefabricated RCS composite frame structure (space frame) are limited. In this study, a half-scale prefabricated RCS space frame structure (two-storey, 1 × 2-bay) was designed and manufactured and then tested through the sudden failure of the long-side central column. The weakened part of failure column was rapidly pulled out using vehicle traction force, and displacement was obtained with a dynamic data acquisition instrument supplemented by high-speed camera to record the deformation process of the structure. Additionally, the remaining structure displacement variation and the beam-to-column connections of fem model under progressive collapse were simulated using SAP2000. The FEA results were compared with the experimental results to verify the effectiveness of the numerical analysis. Experimental results demonstrated that the prefabricated RCS composite frame structure designed in accordance with Chinese building codes shows improved resistance to progressive collapse. The dynamic effect demonstrates no significant influence on the prefabricated RCS composite frame structure, and the suggested dynamic amplification coefficient is 1.28. Steel plates (A, B, and C) of the beam-to-column connection are the weak part of the structural failure, and appropriate measures should be applied to strengthen the steel plate of the beam-to-column connection when the prefabricated RCS composite frame structure is designed to resist progressive collapse. SAP2000 FEM program verified that the numerical simulation results are basically consistent with the experimental results.


2021 ◽  
pp. 136943322199249
Author(s):  
Riza Suwondo ◽  
Lee Cunningham ◽  
Martin Gillie ◽  
Colin Bailey

This study presents robustness analyses of a three-dimensional multi-storey composite steel structure under the action of multiple fire scenarios. The main objective of the work is to improve current understanding of the collapse resistance of this type of building under different fire situations. A finite element approach was adopted with the model being firstly validated against previous studies available in the literature. The modelling approach was then used to investigate the collapse resistance of the structure for the various fire scenarios examined. Different sizes of fire compartment are considered in this study, starting from one bay, three bays and lastly the whole ground floor as the fire compartment. The investigation allows a fundamental understanding of load redistribution paths and member interactions when local failure occurs. It is concluded that the robustness of the focussed building in a fire is considerably affected by the size of fire compartments as well as fire location. The subject building can resist progressive collapse when the fire occurs only in the one-bay compartment. On the other hand, total collapse occurs when fire is located in the edge three-bay case. This shows that more than one fire scenario needs to be taken into consideration to ensure that a structure of this type can survive from collapse in the worst-case situation.


2011 ◽  
Vol 199-200 ◽  
pp. 1358-1361 ◽  
Author(s):  
Bing Chen ◽  
Zheng Tian ◽  
Zhong Jun Yin

This paper established a high-speed tracked vehicle dynamics model, and simulated the transient response of sprocket when the vehicle is running at 60km/h on the D class road. the finite element model of the single tooth in mesh is established in Ansys and the rigid-flexible coupling model of "trackboard- sprocket" is established in RecurDyn. The dynamic stress and strain fringe of the sprocket’s gear ring is achieved by analysis. Simulation results show that the stress of tracked vehicle sprocket gear root and the fixed gear bolt hole is larger, and the stress concentration is detected at the edge of contacted tooth. The simulation results provide the calculation basis for the optimization of the high-speed tracked vehicle system and its lifespan prediction.


2013 ◽  
Vol 405-408 ◽  
pp. 835-840
Author(s):  
Tie Cheng Wang ◽  
Zhi Ping Li ◽  
Hai Long Zhao

In this study, three tie force models of a 10-storey concrete frame structure were prepared to investigate the effects of these methods on the resistance of frame structures against progressive collapse. Four cases of different first-storey column removed were considered using nonlinear static analysis method and their performances were compared with each other. From the nonlinear static analysis, the tie force methods in DoD 2005 and DoD 2009 cannot improve progressive collapse resistance of the structure because horizontal cables don't play a full role. X-type tension cables provide alternative load paths after loss of a single column, and improve progressive collapse resistance of the structure. The X-type tie force model remained in stable condition after sudden removal of a corner column, an exterior column, or an interior column in the first storey.


2019 ◽  
Vol 200 ◽  
pp. 109719 ◽  
Author(s):  
Yun Zhou ◽  
Taiping Chen ◽  
Yilin Pei ◽  
Hyeon-Jong Hwang ◽  
Xiang Hu ◽  
...  

2014 ◽  
Vol 501-504 ◽  
pp. 1498-1502
Author(s):  
Shao Wei Duan ◽  
Wei Huang ◽  
Xian Tan

With a 10 layer of concrete filled square steel tubular column beam frame structure as the object of study ,discrete structure into multiparticle system and establish a dynamic differential equation,solve this dynamic equation by Newmark -β method .Establish thefinite element model of the structure is based on Sap2000 ,then dynamic elastic-plastic time history analysis are carried out, the research results show that the dynamic characteristics of structure,s story drifts,story shear and acceleration with energy dissipating devices are smaller than the model without energy dissipating devices under different earthquake intensities. the damped effect is considered obvious.


2011 ◽  
Vol 243-249 ◽  
pp. 531-535
Author(s):  
Yan Li Shi ◽  
Xiao Yan Zhou ◽  
Wen Da Wang

Progressive collapse is a chain reaction of failure that relates local damage to large disproportional scale collapse in a structure. At present the research against progressive collapse focused on reinforced concrete (RC) and steel structures. This paper presented the state-of-the-art of study on progressive collapse of structures. A preliminary analysis on the progressive collapse of a typical planar composite frame with concrete-filled steel tubular (CFST) columns was performed using ABAQUS. Some general conclusions were given to refer for the further research on the composite frames.


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