scholarly journals XFEM-Based Multiscale Simulation on Monotonic and Hysteretic Behavior of Reinforced-Concrete Columns

2020 ◽  
Vol 10 (21) ◽  
pp. 7899
Author(s):  
Hongbing Chen ◽  
Bin Xu ◽  
Jiang Wang ◽  
Xin Nie ◽  
Yi-Lung Mo
Keyword(s):  
Reinforced Concrete ◽  
Multiscale Simulation ◽  
Local Failure ◽  
Hysteretic Behavior ◽  
Multiscale Models ◽  
Rc Columns ◽  
Rc Structures ◽  
Beam Elements ◽  
Modeling Approach ◽  
Scale Models

The extended finite element method (XFEM) is efficient in simulating crack initiation and its evolution process for reinforced-concrete (RC) structures due to its ability to solve fracture problems. Moreover, the multiscale numerical simulation helps understand global and local failure behavior of RC structures simultaneously. In this study, the XFEM-based multiscale modeling approach was proposed to investigate the monotonic and hysteretic performance of RC columns. Firstly, two-scale models composed of fiber beam elements and XFEM-based solid elements with homogeneous material assumptions were established using compiled material subroutines for fiber beam elements. Secondly, the accuracy of XFEM-based two-scale analysis in predicting the hysteretic behavior of tested RC columns was verified by comparing the crack morphology and load-displacement curve obtained from tested specimens under different axial compression ratios (ACRs) and two-scale models using the concrete damaged plasticity (CDP) model. Thirdly, multiscale models of RC columns were constructed with fiber beam elements, XFEM-based solid elements and mesoscopic concrete models composed of mortar, interfacial transition zone (ITZ) and aggregates with different geometric shapes and distribution patterns. Finally, the XFEM-based multiscale simulation was employed to investigate the influence of mesoscale structure variation of concrete on both global behavior and local failure patterns of RC columns subjected to monotonic loading. The simulation results of multiscale models established with CDP model and XFEM were comparatively discussed in depth. The XFEM-based multiscale simulation developed in this study provides an efficient modeling approach for investigating the stochastic nature of cracking behavior in RC columns.

scholarly journals Equivalent Viscous Damping Ratio Model for Flexure Critical Reinforced Concrete Columns

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Qin Zhang ◽  
Zong-yan Wei ◽  
Jin-xin Gong ◽  
Ping Yu ◽  
Yan-qing Zhang
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Damping Ratio ◽  
Hysteretic Behavior ◽  
Viscous Damping ◽  
Ratio Model ◽  
Rc Columns ◽  
Equivalent Viscous Damping ◽  
Rc Structures ◽  
Energy Dissipation Capacity

In order to determine the energy dissipation capacity of flexure critical reinforced concrete (RC) columns reasonably, an expression for describing the hysteretic behavior including loading and unloading characteristics of flexure critical RC columns is presented, and then, a new equivalent viscous damping (EVD) ratio model including its simplified format, which is interpreted as a function of a displacement ductility factor and a ratio of secant stiffness to yield stiffness of columns, is developed based on the proposed hysteretic loop expression and experimental data from the PEER column database. To illustrate the application of the proposed equivalent damping ratio model, a case study of pushover analysis on a flexure critical RC bridge with a single-column pier is provided. The analytical results are also compared with the results obtained by other models, which indicate that the proposed model is more general and rational in predicting energy dissipation capacity of flexure critical RC structures subjected to earthquake excitations.

scholarly journals Effects of Tension Reinforcement Ratio on Ductility of Mid-Rise Reinforced Concrete Structures

2018 ◽  
Vol 1 (1) ◽  
pp. 702-708
Author(s):  
Onur Onat ◽  
Burak Yön
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Concrete Structures ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Structures ◽  
Rc Structures ◽  
Beam Elements ◽  
First Case ◽  
Rc Structure ◽  
Determine Effect

Failure mode of reinforced concrete (RC) structures are classified according to tension reinforcement ratio of beam elements. To determine effect of tension reinforcement ratio on performance of RC structure, two planar RC structure were selected. One of them is 5 stories other of them is 7 stories. Two different concrete class, C20 and C25, were considered for analysis. Three tension reinforcement combinations were considered, three different tension reinforcement ratios were used. First case is the ratio of the tension reinforcement is lower than that of the compression reinforcement, second case is the ratio of the tension reinforcement is equal to the ratio of the compression reinforcement and third case is the ratio of the tensile reinforcement is higher than the compression reinforcement.

scholarly journals Concept of Computer Vision Based Algorithm for Detecting Thermal Anomalies in Reinforced Concrete Structures

Proceedings ◽  
2019 ◽  
Vol 27 (1) ◽  
pp. 18
Author(s):  
Michele De Filippo ◽  
Sasan Asadiabadi ◽  
Nigel Ko ◽  
Harris Sun
Keyword(s):  
Computer Vision ◽  
Reinforced Concrete ◽  
Qualitative Assessment ◽  
Current Status ◽  
Rc Buildings ◽  
Rc Structures ◽  
Thermal Anomalies ◽  
Beam Elements ◽  
Image Capturing ◽  
Thermal Infrared Anomalies

In Hong Kong, there is great abundancy of aged buildings and infrastructures for which a re-assessment of the current status is needed. Water exfiltrations/infiltrations, deteriorating insulations, thermal bridges and regions of failure are among the most recurrent symptoms to be found in existing Reinforced Concrete (RC) structures. Diagnosis of such symptoms, in the form of thermal infrared anomalies, is usually performed through infrared (IR) image capturing, followed by qualitative assessment. This paper presents a novel automated computer-vision-based method for detecting thermal anomalies. Such Computer-Vision (CV) algorithm is tested on different thermal scenarios including beam elements, roofs and entire façades of RC buildings. Thermal anomalies related to cases of water leakages, moisture trapping and debonding are successfully detected. The authors intend to undertake further research for successfully implementing the method for detecting also other thermal dissimilarities.

scholarly journals Seismic performance assessment of RC columns with interlocking hoops

2021 ◽  
Author(s):  
Tae-Hoon Kim
Keyword(s):  
Reinforced Concrete ◽  
Performance Assessment ◽  
Seismic Performance ◽  
Evaluation System ◽  
Damage Index ◽  
Seismic Performance Assessment ◽  
Rc Columns ◽  
Rc Structures ◽  
Damage Indices ◽  
Transverse Steel

The aim of this study is to analytically assess the seismic performance of reinforced concrete (RC) columns with interlocking hoops using a novel damage index, and to provide data for developing next generation seismic design criteria. Seismic performance of RC columns is controlled by the level of confinement provided by transverse steel. Interlocking hoops are commonly used in RC columns because they can provide more effective confinement than rectangular hoops. Three RC interlocking columns were tested under a constant axial load and a cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), is used to analyze RC structures. Novel damage indices aim to provide a means of quantifying numerically the performance level in RC columns with interlocking hoops sustained under earthquake loading. The proposed numerical method for the seismic performance assessment of interlocking columns is verified by comparison with the experimental results.

scholarly journals Experimental Behavior of Existing RC Columns Strengthened with HPFRC Jacket under Concentric and Eccentric Compressive Load

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 521
Author(s):  
Paolino Cassese ◽  
Costantino Menna ◽  
Antonio Occhiuzzi ◽  
Domenico Asprone
Keyword(s):  
Reinforced Concrete ◽  
Axial Load ◽  
High Performance ◽  
Compressive Load ◽  
Bending Moment ◽  
Critical Issue ◽  
Fiber Reinforced Concrete ◽  
Rc Columns ◽  
Rc Structures ◽  
Rc Building

Reinforced concrete (RC) structures built before the 1970 represent a large portion of the existing European buildings stock. Their obsolescence in terms of design criteria, materials, and functionality is becoming a critical issue for guaranteeing adequate compliance with current structural codes. Recently, a new jacketing system based on the use of high-performance fiber-reinforced concrete (HPFRC) has been introduced for strengthening existing RC building members. Despite the promising aspects of the HPFRC jacketing technique, currently, a comprehensive and systematic technical framework for its implementation is still missing. In this paper, the experimental performance of RC columns strengthened with the HPFRC jacket subjected to pure axial load and combined axial load-bending moment uncoupled from shear is investigated. The test outcomes confirmed a significant improvement of the structural performance for the strengthened columns, especially for higher values of eccentricity. Finally, a standard-based practice-oriented analytical tool for designing retrofit interventions using the HPFRC jacket is proposed. The comparison between the calculated and experimental results revealed a satisfactory prediction capability.

Axial Compression Capacity of Shear-Damaged Reinforced Concrete Columns and Lashing Belt Prestressing

2016 ◽  
Vol 711 ◽  
pp. 1012-1018
Author(s):  
Kozo Nakada ◽  
Kochi Masaaki ◽  
Yu Yun Dong ◽  
Long Yu
Keyword(s):  
Reinforced Concrete ◽  
Axial Compression ◽  
Concrete Columns ◽  
Hysteretic Behavior ◽  
Load Carrying Capacity ◽  
Vertical Load ◽  
Shear Strengthening ◽  
Rc Columns ◽  
Load Carrying ◽  
Strength And Ductility

The compressive strength and ductility of concrete can be considerably improved by lateral confinement. In this study, an emergency seismic retrofit technique using lashing belt prestressing is used as to manually retrofit damaged reinforced concrete (RC) columns. The initial prestressing is an important aspect of this technique and is introduced by the ratchet buckle. Thus, this technique offers active and passive confinement as well as shear strengthening. Furthermore, diagonal cracks in the damaged RC columns can be closed by using the active confinement of lashing belts, and the lateral and vertical load-carrying capacity and ductility of the damaged RC columns are recovered. In this study, the recovered axial compression capacity of the retrofitted RC columns and repaired RC columns using epoxy resin was investigated. Finally, the hysteretic behavior of the shear-damaged RC columns after the proposed emergency retrofit was investigated.

Seismic Behavior of RC Columns With Corner Focus Longitudinal Bars

2013 ◽  
Vol 470 ◽  
pp. 876-879
Author(s):  
Kun Song ◽  
Zhen Bao Li
Keyword(s):  
Reinforced Concrete ◽  
Seismic Behavior ◽  
Concrete Columns ◽  
Hysteretic Behavior ◽  
Frame Structures ◽  
Seismic Action ◽  
Multiaxial Loading ◽  
Feature Points ◽  
Rc Columns ◽  
The Wenchuan Earthquake

Many frame structures were damaged for the column hinge mechanism in the Wenchuan earthquake because of the biaxial seismic action. Four reinforced concrete columns with corner focus longitudinal bars were tested to improve the seismic behavior of RC columns subjected to multiaxial loading. The hysteretic behavior, skeleton curves and feature points were discussed. The results indicate that the method can improve seismic behavior of RC columns

Experimental Study on the Effect of Moisture Content on Hysteretic Behavior of Reinforced Concrete Columns

2018 ◽  
Vol 12 (1) ◽  
pp. 47-61
Author(s):  
Wenjuan Lv ◽  
Baodong Liu ◽  
Ming Li ◽  
Lin Li ◽  
Pengyuan Zhang
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Moisture Content ◽  
Early Stage ◽  
Damping Ratio ◽  
Concrete Columns ◽  
Hysteretic Behavior ◽  
Cyclic Test ◽  
Experimental Result ◽  
Reinforced Concrete Columns

Background: For reinforced concrete structures under different humid conditions, the mechanical properties of concrete are significantly affected by the moisture content, which may result in a great change of the functional performance and bearing capacity. Objective: This paper presents an experiment to investigate the influence of the moisture content on the dynamic characteristics and hysteretic behavior of reinforced concrete column. Results: The results show that the natural frequency of reinforced concrete columns increases quickly at an early stage of immersion, but there is little change when the columns are close to saturation; the difference between the natural frequencies before and after cyclic test grows as the moisture content rises. The damping ratio slightly decreases first and then increases with the increase of moisture content; the damping ratio after the cyclic test is larger than before the test due to the development of the micro-cracks. Conclusion: The trend of energy dissipation is on the rise with increasing moisture content, although at an early stage, it decreases slightly. According to the experimental result, a formula for the moisture content on the average energy dissipation of reinforced concrete columns is proposed.

scholarly journals Experimental Research on Reinforced Concrete Columns Strengthened with Steel Jacket and Concrete Infill

2021 ◽  
Vol 11 (9) ◽  
pp. 4043
Author(s):  
Aleksandar Landović ◽  
Miroslav Bešević
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Experimental Research ◽  
Failure Modes ◽  
Steel Tube ◽  
Rc Columns ◽  
Rc Column ◽  
Steel Jacket ◽  
Ductile Behavior

Experimental research on axially compressed columns made from reinforced concrete (RC) and RC columns strengthened with a steel jacket and additional fill concrete is presented in this paper. A premade squared cross-section RC column was placed inside a steel tube, and then the space between the column and the tube was filled with additional concrete. A total of fourteen stub axially compressed columns, including nine strengthened specimens and five plain reinforced concrete specimens, were experimentally tested. The main parameter that was varied in the experiment was the compressive strength of the filler concrete. Three different concrete compression strength classes were used. Test results showed that all three cross-section parts (the core column, the fill, and the steel jacket) worked together in the force-carrying process through all load levels, even if only the basic RC column was loaded. The strengthened columns exhibited pronounced ductile behavior compared to the plain RC columns. The influence of the test parameters on the axial compressive strength was investigated. In addition, the specimen failure modes, strain development, and load vs. deformation relations were registered. The applicability of three different design codes to predict the axial bearing capacity of the strengthened columns was also investigated.

Sign in / Sign up

Export Citation Format

Share Document