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.

Failure by corrosion in PC bridges: a case history of a viaduct in Italy

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Piero Colajanni ◽  
Antonino Recupero ◽  
Giuseppe Ricciardi ◽  
Nino Spinella
Keyword(s):  
Prestressed Concrete ◽  
Design Methodology ◽  
Progressive Collapse ◽  
Numerical Analyses ◽  
Existing Structures ◽  
History Of ◽  
Progressive Collapse Analysis ◽  
Practical Implications ◽  
Post Tensioned

Purpose The paper illustrates a viaduct collapse due to corrosion phenomena. Moreover, a contribution to the issues related to both the control of existing structures and design methods to be followed for the construction of new buildings is provided. Design/methodology/approach The objectives were achieved by in situ observations and numerical analyses. The effects of corrosion phenomena are investigated, and the progressive collapse analysis is provided to be helpful in this case. Findings The damages induced by corrosion phenomena have caused the collapse of the viaduct taken in to account. The performed numerical analyses were able to reproduce the effects of corrosion in terms of reduction of wires diameter. Research limitations/implications The research is limited to prestressed concrete viaduct with post-tensioned cables. Practical implications A monitoring plan, subdivided in several phases, is suggested, to avoid critical situations as these described. Originality/value The case study brought useful information on the effects of corrosion on the decks section, showing how the technology in post-tensioned cables is usually insidious and prone to the issues relating to corrosion of the wires

Field evaluation and model test of a composite wing-girder bridge

1987 ◽  
Vol 14 (6) ◽  
pp. 753-762 ◽  
Author(s):  
John E. Breen ◽  
Michael E. Kreger ◽  
Christopher D. White ◽  
Gordon C. Clark
Keyword(s):  
Prestressed Concrete ◽  
Load Transfer ◽  
Field Evaluation ◽  
Field Testing ◽  
Scale Model ◽  
Construction Monitoring ◽  
Service Load ◽  
Girder Bridge ◽  
High Level ◽  
Post Tensioned

This paper presents the key observations and conclusions from the evaluation of an innovative "loose-fit" composite, post-tensioned concrete wing-girder bridge proposed for an elevated interstate highway expansion in an urban environment. The evaluation program included both testing to destruction of a 1/2-scale model of a partial span as well as construction monitoring and field testing at service load levels of a full-scale prototype two-span bridge. Results of both construction measurements and loading tests were compared with analytical predictions. Laboratory tests showed the composite behavior of the wing-girder joint to be fully effective and a high level of load transfer between wings to be present. Recommendations for modification of the prototype design are made to improve constructibility, durability, structural performance, and economy. Key words: box girder, bridge, post-tensioned, prestressed concrete, reinforcement, stresses, temperature, tendons.

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.

scholarly journals Simplified Compression Arch Action Model for R/C Beam-column Assemblages

2019 ◽  
pp. 1-11
Author(s):  
Fouad B. A. Beshara ◽  
Ahmed A. Mahmoud ◽  
Osama O. El-Mahdy ◽  
Ahmed N. Khater
Keyword(s):  
Progressive Collapse ◽  
Mean Values ◽  
Concrete Confinement ◽  
Proposed Model ◽  
Arching Action ◽  
Action Model ◽  
Arch Action ◽  
Parametric Studies ◽  
Action Models ◽  
Column Removal Scenario

A set of analytical equations are developed for calculating the beam-column assemblage flexure action capacity and compression arching action capacity under a middle column removal scenario. The suggested equations covered most of the main parameters affecting the assemblage behavior including seismic detailing, longitudinal reinforcement ratios, concrete confinement, and the contribution of concrete flanged slabs. The proposed analytical model for predicting the flexural and compression arching action capacities is validated with a large number of experimental results. The model provides a good estimation for 79 beam-column assemblages with several geometrical, reinforcement configurations, and material parameters. The mean values of the experimental to the theoretical ratio for calculating flexure and compression arching capacities are 1.15 and 1.16, respectively. The predictions of previous compression arch action models are found to be more conservative. Finally, the proposed model is utilized in parametric studies including all key parameters that affected resistance of the beam-column assemblages against progressive collapse.

Research on the resistance of modified bolted connection under progressive collapse scenario

2021 ◽  
pp. 136943322110048
Author(s):  
Xian Rong ◽  
Xiuchen Xu ◽  
Yansheng Du
Keyword(s):  
Failure Modes ◽  
Load Transfer ◽  
Progressive Collapse ◽  
Load Resistance ◽  
Conventional Technique ◽  
Finite Element Models ◽  
Bolted Connection ◽  
Structural Resistance ◽  
Chord Rotation ◽  
Simplified Mechanical Model

Beam-to-column connection configurations, such as welded, bolted, and mixed welded-bolted connections, play an important role in structural resistance and ductility under middle column-removal scenarios. This paper illustrates full-scale laboratory tests of two steel frame assemblies with different connection details under the progressive collapse scenario. One specimen adopts the modified conventional technique which has reinforced welded flange-bolted web connection (SC-WR), and the other specimen uses a slotted-hole connection based on the former (SC-WB). The failure modes, load transfer mechanism, and vertical resistance are analyzed in the test. Both connection configurations exhibit satisfactory load resistance and ductility supply. Specimen SC-WB shows the higher ultimate vertical capacity and greater chord rotation at later catenary stage due to a sufficient redistribution of the stress with the modified bolted shear tab. Moreover, finite element models (FEM) are developed and validated against the test data. FEM can accurately simulate the mechanical behaviors and the failure of specimens, which can provide an effective reference for the beam-to-column connection configurations in similar working conditions. Finally, a simplified mechanical model is exhibited in accordance with the experimental and numerical results to reveal the effect of the catenary mechanism. This result suggests that the duration of the catenary mechanism, rather than the magnitude of the axial force, plays an essential role in the resistance of vertical load.

scholarly journals Progressive Collapse Potential of Ordinary Moment Resisting R/C Frames

2019 ◽  
pp. 1-13
Author(s):  
Ahmed N. Khater ◽  
Fouad B. A. Beshara ◽  
Ahmed A. Mahmoud ◽  
Osama O. El-Mahdy
Keyword(s):  
Progressive Collapse ◽  
Constitutive Models ◽  
Numerical Procedure ◽  
Suggested Approach ◽  
Catenary Action ◽  
Collapse Potential ◽  
Numerical Predictions ◽  
Steel Bars ◽  
Moment Resisting ◽  
Column Removal Scenario

A nonlinear numerical procedure in joint with suitable constitutive concrete and steel models is proposed to simulate the structural behavior and progressive collapse potential of ordinary moment-resisting frames exposed to a middle column removal scenario. Previous experimental results are used to verify the proposed non-linear finite element modelling using ANSYS program. The geometrical discretization of the ANSYS in accordance with concrete and reinforcing steel bars constitutive models have been employed in the suggested approach. The proposed numerical model succeeded in simulating the pre-peak and post-peak behavior in addition to the catenary action stage until reaching the failure of ordinary frames specimens. Numerical predictions are given for the cracking patterns, load-deflection curves, and steel strain-deflection relations.

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.

scholarly journals A Modified Catenary Model with Application to the Analysis and Design of Retrofit Cables for Progressive Collapse

2018 ◽  
Vol 3 (3) ◽  
pp. 26 ◽  
Author(s):  
Leven Deputy ◽  
Yasha Zeinali ◽  
Brett Story
Keyword(s):  
New York ◽  
Progressive Collapse ◽  
World Trade Center ◽  
Load Resistance ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Catenary Action ◽  
Analysis And Design ◽  
Structural Frames ◽  
Existing Frames

Progressive collapse, the extensive or complete collapse of a structure resulting from the failure of one or a small number of structural components, has become a focus of research efforts and design considerations following events occurring at the Ronan Point apartment building in London, the Murrah Federal Building in Oklahoma City, and the World Trade Center in New York City. A principle research and design area for progressive collapse investigates the behavior of structural frames when column support is removed. The mechanism that results from loss of column support in structural frames characteristically involves beams that are unable to provide sufficient flexural resistance. Cable retrofit is one method to enhance existing frames and supplement or replace the post-mechanism beam load resistance with straight-legged catenary resistance after a column removal. The cables are located linearly along the beam geometry and are affixed at beam supports. This paper investigates both static and dynamic behavior of the catenary action of retrofit cables, which include both the linear and nonlinear material behavior of the cable material. Moreover, a simplified model serves as the basis for retrofit cable design is presented. Finite element modeling and experimentation in this paper verify and validate the applicability of the model. Finally, a framework for developing a procedure for retrofit cable design is presented.

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