scholarly journals Effects of Corrosion on Compressive Arch Action and Catenary Action of RC Frames to Resist Progressive Collapse Based on Numerical Analysis

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2662
Author(s):  
Lu Zhang ◽  
Tingyu Wei ◽  
Hongyu Li ◽  
Jian Zeng ◽  
Xiaofang Deng
Keyword(s):  
Numerical Model ◽  
Mechanical Performance ◽  
Progressive Collapse ◽  
Significant Loss ◽  
Catenary Action ◽  
Rc Frames ◽  
Collapse Resistance ◽  
Arch Action ◽  
Rebar Corrosion ◽  
Modeling Strategy

Many negative factors can influence the progressive collapse resistance of reinforced concrete (RC) frame structures. One of the most important factors is the corrosion of rebar within the structure. With increasing severity of corrosion, the duration, robustness, and mechanical performance can be greatly impaired. One specific side effect of rebar corrosion is the significant loss of protection against progressive collapse. In order to quantify the effects of rebar corrosion on load-resisting mechanisms (compressive arch action (CAA) and tensile catenary action (TCA)) of RC frames, a series of numerical investigations were carried out in this paper. The previous experimental results reported in the literature provide a benchmark for progressive collapse behavior as a sound condition and validate the proposed numerical model. Furthermore, based on the verified numerical model, the CAA and TCA with increasing corrosion and an elapsed time from 0 to 70 years are investigated. Comparing with the conventional empirical model, the proposed numerical model has shown the ability and feasibility in predicting the collapse resistance capacity in structures with corroded rebar. Therefore, this numerical modeling strategy provides comprehensive insights into the change of load-resisting mechanisms in these structures, which can be beneficial for optimizing the design.

Progressive collapse test of assembled monolithic concrete frame spatial substructures with different anchorage methods in the beam–column joint

2020 ◽  
Vol 23 (9) ◽  
pp. 1785-1799 ◽  
Author(s):  
Wang-Xi Zhang ◽  
Hao Wu ◽  
Jin-Yi Zhang ◽  
Hyeon-Jong Hwang ◽  
Wei-Jian Yi
Keyword(s):  
Progressive Collapse ◽  
Resistance Mechanism ◽  
Structural Performance ◽  
Catenary Action ◽  
Lap Splice ◽  
Concrete Frame ◽  
Collapse Resistance ◽  
Load Carrying ◽  
Arch Action ◽  
Column Joint

In this study, three two-third-scale assembled monolithic concrete spatial frame substructures with three beams and four columns were tested to evaluate progressive collapse resistance. The test parameters are anchorage methods, such as 90° hooked bar, lap splice in U-shaped assembled monolithic concrete beam, and headed bar using welded anchor plate. Force–displacement-controlled pseudo-static loading was applied to the mid-column. On the basis of structural performance, including load-carrying capacity, deformation capacity, crack distribution, rebar strain, and failure mode, the progressive collapse resistance mechanism of the specimens was analyzed. Test results showed that three types of cracks were developed: initial flexural cracks in beam–column joints, diagonal cracks due to compressive arch action, and tension cracks due to catenary action. The specimen using the headed bar exhibited the best progressive collapse performance, whereas the specimen using the lap splice connection showed the worst structural performance. Regardless of anchorage methods, bond failure did not occur during progressive collapse. The progressive collapse performance of the specimen was assessed based on Chinese and American codes.

Numerical investigation on load transfer mechanism of bonded post-tensioned concrete beam-column substructures against progressive collapse

2020 ◽  
pp. 136943322098165
Author(s):  
Kai Qian ◽  
Hai-Ning Hu ◽  
Yun-Hao Weng ◽  
Xiao-Fang Deng ◽  
Ting Huang
Keyword(s):  
Prestressed Concrete ◽  
Load Transfer ◽  
Numerical Models ◽  
Progressive Collapse ◽  
Load Resistance ◽  
Catenary Action ◽  
Parabolic Profile ◽  
Arch Action ◽  
Column Removal Scenario ◽  
Post Tensioned

This paper presents the high-fidelity finite-element-based numerical models for modeling the behavior of prestressed concrete (PC) beam-column substructures to resist progressive collapse under column removal scenario. After careful calibration against data, the validated numerical models are further employed to shed light on the influence of bonded post-tensioned tendons (BPT) with a parabolic profile on the load transfer mechanisms of PC frames against progressive collapse. The effects of parameters, including initial effective prestress, profile of tendon and lateral constraint stiffness at the beam ends, are also investigated. The study shows that, due to the presence of prestressed tendons, the mobilization of compressive arch action in the beam at small deflections demands stronger lateral constraints, and the ultimate load resistance of PC beam-column substructures depends on combined catenary action from non-prestressed reinforcement and BPT at large deflections. For a given constraint stiffness, the initial effective prestress of BPT has less significant effect on the overall structural behavior. For prestressed tendon, a straight profile usually employed in structural strengthening can improve the initial structural stiffness and yield strength, but is less effective in enhancing the ultimate resistance against progressive collapse than the parabolic profile.

Progressive Collapse Resistance Demand of RC Frames under Catenary Mechanism

2014 ◽  
Vol 111 (5) ◽  
Author(s):  
Yi Li ◽  
Xinzheng Lu ◽  
Hong Guan ◽  
Lieping Ye
Keyword(s):  
Progressive Collapse ◽  
Rc Frames ◽  
Collapse Resistance

Progressive Collapse Resistance Demand of RC Frames under Catenary Mechanism

2014 ◽  
Vol 111 (5) ◽  
Author(s):  
Yi Li ◽  
Xinzheng Lu ◽  
Hong Guan ◽  
Lieping Ye
Keyword(s):  
Progressive Collapse ◽  
Rc Frames ◽  
Collapse Resistance

Improving the tie force method for progressive collapse design of RC frames

2018 ◽  
Vol 9 (4) ◽  
pp. 520-531 ◽  
Author(s):  
Arash Naji
Keyword(s):  
Design Methodology ◽  
Progressive Collapse ◽  
Limit State ◽  
Content Type ◽  
Catenary Action ◽  
Closed Form Solutions ◽  
Rc Frames ◽  
Orthogonal Beams ◽  
Similar Equation ◽  
Good Agreement

Purpose The purpose of this paper is to recover the deficiency of existing tie force (TF) methods by considering the decrease in section strength due to cracking and by selecting limit state of collapse according to section properties. Design/methodology/approach A substructure is selected by isolating the connected beams from the entire structure. For interior joints, the TFs in the orthogonal beams are obtained by catenary action. For corner joints, the TFs are assessed by beam action. For edge joints, however, the resistance is gained by greater of the resistance under catenary action for periphery beams and beam action for all the connecting beams in both directions. For catenary action, the TF capacities must satisfy Equation (20). On the other hand, for beam action, the TF must satisfy Equation (16), while R is calculated from Equation (17). In the case where the length of the connecting beams is similar, Equation (19) can be used. Findings Closed form solutions are available for TFs on both beam and catenary stages. Originality/value The proposed formulation makes designing more practical and convenient. However, the proposed formulation had good agreement with experimental results.

scholarly journals Strengthening of Precast RC Frame to Mitigate Progressive Collapse by Externally Anchored Carbon Fiber Ropes

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1306
Author(s):  
Jianwu Pan ◽  
Xian Wang ◽  
Hao Dong
Keyword(s):  
Carbon Fiber ◽  
Load Capacity ◽  
Progressive Collapse ◽  
Analytical Models ◽  
Deformation Condition ◽  
Strengthening Effect ◽  
Rc Frame ◽  
Catenary Action ◽  
Rc Frames ◽  
Collapse Failure

The robustness of precast reinforced concrete (RC) frames is relatively poor, while the precast RC frames are strengthened to mitigate progressive collapse, avoiding “strong beams and weak columns” and the anchorage failure of strengthening materials under large deformation condition are the key problems. Aiming to discuss these problems, this paper carried out an experimental research of strengthening on three half-scale assembled monolithic frame subassemblages to mitigate progressive collapse. One specimen was strengthened by implanting carbon fiber rope (CFR) with polymer into concrete, one specimen was strengthened by binding CFR with special knot, and the last one was not strengthened. The failure mode, collapse failure mechanism and strengthening effect of subassemblages were discussed. Analytical models of load capacity increment contributed by CFR and construction suggestions of precast RC frame to mitigate progressive collapse were proposed. The results indicated that none of the strengthened specimens had anchorage failure. The two strengthening methods significantly increased the load capacity of the subassemblages in the catenary action (CA) stage with little effect on the flexural action (FA) stage and compressive arch action (CAA) stage.

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