scholarly journals Investigation of Deformation-Based Damage Limits of RC Columns for Different Seismic Codes

2021 ◽  
Author(s):  
Saeid Foroughi ◽  
◽  
Suleyman Bahadir Yuksel ◽  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Columns ◽  
Seismic Loads ◽  
Existing Buildings ◽  
Performance Limits ◽  
Seismic Evaluation ◽  
Rc Columns ◽  
Reinforced Concrete Columns ◽  
Seismic Codes ◽  
Parametric Studies

The seismic performance of reinforced-concrete columns is related to the expected damage limits under seismic loads and how this damage relates to safety of the structure. In order to assess the performance of reinforced-concrete columns under seismic loads, performance-based deformation and damage limits are proposed by the seismic codes. Adequacy of the deformation and damage limit levels given in the codes such as Seismic Evaluation and Retrofit of Existing Buildings Standard, ASCE/SEI-41 (2017) and Turkish Building Earthquake Code (2018) were evaluated by carrying out parametric studies for RC columns. Reinforced-concrete circular columns are designed in parametric studies to present the effects of various parameters such as concrete compressive strength, axial load levels and spiral reinforcement ratio on performance-based damage limits. Performance limits corresponding to each performance levels obtained by different seismic guidelines were compared. When the results obtained from the analyzes are examined, it has been observed that there are significantly different results in the cross-section damage limits values of ASCE/SEI-41 (2017) and TBEC (2018) regulation, which can change the performance level of the building. TBEC (2018) gives approximately 50% conservative limitations when they are compared with the ASCE/SEI-41 (2017) limitations. As a result, TBDY (2018) seems to offer safer and ductile solutions than ASCE ASCE/SEI-41 (2017).

Seismic Evaluation of Existing Reinforced Concrete Building Columns

1996 ◽  
Vol 12 (4) ◽  
pp. 715-739 ◽  
Author(s):  
Abraham C. Lynn ◽  
Jack P. Moehle ◽  
Stephen A. Mahin ◽  
William T. Holmes
Keyword(s):  
Reinforced Concrete ◽  
Axial Load ◽  
Lateral Displacement ◽  
Concrete Columns ◽  
Vertical Load ◽  
Seismic Evaluation ◽  
Severe Damage ◽  
Reinforced Concrete Columns ◽  
Concrete Building ◽  
Constant Axial Load

Past earthquakes have emphasized the vulnerability of reinforced concrete columns having details typical of those built before the mid-1970's. These columns are susceptible to axial-flexural, shear, and bond failures, which subsequently may lead to severe damage or collapse of the building. Research was undertaken to investigate the lateral and vertical load-resisting behavior of reinforced concrete columns typical of pre-1970's construction. Eight full-scale specimens were constructed and were loaded with constant axial load and increasing cyclic lateral displacement increments until failure. Test data are presented and compared with behavior estimated by using various evaluation methods.

scholarly journals Numerical parametric studies on the fire endurance of fibre-reinforced-polymer-confined concrete columns

2004 ◽  
Vol 31 (6) ◽  
pp. 1090-1100 ◽  
Author(s):  
L A Bisby ◽  
V KR Kodur ◽  
M F Green
Keyword(s):  
Reinforced Concrete ◽  
Holistic Approach ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
Reinforced Polymer ◽  
Fire Endurance ◽  
Fibre Reinforced Polymer ◽  
Parametric Studies ◽  
Parking Garages ◽  
Promising Application

Confinement of reinforced concrete columns by circumferential fibre reinforced polymer (FRP) wraps is a promising application of FRP materials for structural strengthening and seismic upgrading of deteriorated or under-strength members. However, if this technique is to be used in buildings, parking garages, and industrial structures, then the ability of FRP materials and FRP-wrapped columns to withstand the effects of fire must be demonstrated and evaluated. This paper presents the results of parametric studies conducted using a previously presented and partially validated numerical fire simulation model to investigate the effects of a number of parameters on the fire behaviour of FRP-wrapped reinforced concrete columns. It is demonstrated that appropriately designed and adequately protected FRP-wrapped reinforced concrete columns are capable of achieving fire endurances equivalent to conventionally reinforced concrete columns. Furthermore, this study also suggests that a holistic approach to the fire design of FRP-wrapped members is required, rather than an approach based on the specific performance of the FRP materials. Design recommendations for the fire-safe design of FRP-wrapped concrete columns are presented and discussed.Key words: reinforced concrete, rehabilitation, strengthening, fibre reinforced polymer, fire endurance, fire insulation, numerical modelling.

scholarly journals Comparative study on acceptance criteria for non-ductile reinforced concrete columns

2018 ◽  
Vol 51 (4) ◽  
pp. 183-196
Author(s):  
Opabola Eyitayo ◽  
Kenneth J. Elwood
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Concrete Columns ◽  
Deformation Capacity ◽  
Existing Buildings ◽  
Acceptance Criteria ◽  
Reinforced Concrete Columns ◽  
Seismic Demands ◽  
Concrete Buildings ◽  
Direct Rotation

Poor seismic performance of older reinforced concrete buildings in past seismic events has frequently been attributed to failure of non-ductile columns not detailed for seismic demands. The Seismic Assessment of Existing Buildings Guidelines developed in New Zealand (NZ Guideline) provides a performance-based engineering framework for assessment of existing buildings, with concrete buildings covered in section C5. This study compares the probable failure mode and deformation capacity assessed based on NZ Guideline, ASCE/SEI 41-13, and ASCE/SEI 41-17 with the results from quasi-static cyclic tests conducted on 52 rectangular and 13 circular reinforced concrete columns with reinforcement details similar to those of non-ductile columns. Results indicate that the general curvature-based method of the NZ Guideline was not able to identify the observed failure mode but generally provides a conservative estimate of deformation capacity in comparison with ASCE/SEI 41-17. Based on the results of this study, a direct rotation-based acceptance criteria is proposed for NZ Guidelines. Also, slight modifications, to reduce conservatism, have been proposed for the curvature-based method.

Study on Ultimate Bearing Capacity of Reinforced Concrete Columns Combined with FRP

2011 ◽  
Vol 94-96 ◽  
pp. 820-825
Author(s):  
Sai Wu ◽  
Jun Hai Zhao ◽  
Xue Ying Wei
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Columns ◽  
Ultimate Bearing Capacity ◽  
Axial Loads ◽  
Strength Theory ◽  
Rc Columns ◽  
Reinforced Concrete Columns ◽  
Unified Strength Theory ◽  
Good Agreement

This paper based on the unified strength theory, analyzed the ultimate bearing capacity of the reinforced concrete columns combined with FRP under axial loads. First, analyzed the mechanical property of the RC columns combined with FRP. Second, based on the unified strength theory, deduced the three-direction compressive stress of the core concrete and got the unified formula for calculating the ultimate bearing capacity of RC columns combined with FRP. Last, compared the analytical results obtained in this paper with the relevant experimental data, good agreement can be found and it proved the good applicability of the formula. Comparing with other methods in calculating the ultimate bearing capacity of RC columns combined with FRP，this method is well-founded, so it has a significant value in analysis of RC columns combined with FRP.

scholarly journals Behavior of Square RC Short Columns with New Arrangement of Ties Subjected to Axial Load: Experimental and Numerical Studies

2022 ◽  
Author(s):  
Hazem Elbakry ◽  
Tarek Ebeido ◽  
El-Tony M. El-Tony ◽  
Momen Ali
Keyword(s):  
Reinforced Concrete ◽  
Axial Load ◽  
Concrete Columns ◽  
Experimental Program ◽  
Transverse Reinforcement ◽  
Reinforcing Bars ◽  
Rc Columns ◽  
Reinforced Concrete Columns ◽  
Short Columns ◽  
Numerical Studies

Reinforced concrete columns consume large quantities of ties, especially inner cross-ties in columns with large dimensions. In some cases, nesting of the pillars occurs as a result of the presence of cross-ties. The main objective of this paper is to develop new methods for transverse reinforcement in RC columns and investigate their effect on the behavior of the columns. The proposed V-ties as transverse reinforcement replacing the ordinary and cross-ties details are economically feasible. They facilitate shorter construction periods and decrease materials and labor costs. For this purpose, experimental and numerical studies are carried out. In the experimental program, nine reinforced concrete columns with identical concrete dimensions and longitudinal reinforcing bars were prepared and tested under concentric axial load with different tie configurations. The main parameters were the tie configurations and the length (lv) of V-tie legs. As part of the numerical study, the finite element model using the ABAQUS software program obtained good agreement with the experimental results of specimens. A numerical parametric study was carried out to study the influence of concrete compressive strength and longitudinal reinforcement ratio on the behavior of RC columns with the considered tie configurations. Based on the experimental and numerical results, it was found that using V-tie techniques instead of traditional ties could increase the axial load capacity of columns, restrain early local buckling of the longitudinal reinforcing bars and improve the concrete core confinement of reinforced concrete columns.

scholarly journals Near-field explosion effects on reinforced concrete columns: an experimental investigation

2018 ◽  
Vol 45 (4) ◽  
pp. 289-303 ◽  
Author(s):  
Abass Braimah ◽  
Farouk Siba
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Near Field ◽  
Axial Loading ◽  
Concrete Columns ◽  
Load Level ◽  
Experimental Program ◽  
Rc Columns ◽  
Reinforced Concrete Columns ◽  
Scaled Distance

Explosion effects on structures have been an area of active research over the past decades. This is due to the increasing number of terrorists’ action against infrastructures. Although significant amount of work is continuing on the effects of explosions on infrastructures, experimental work involving live explosion testing is limited. Moreover, experimental testing of reinforced concrete (RC) columns subjected to near-field explosions is scant. This paper presents results of an experimental program designed to investigate the effects of near-field explosions on RC columns with different tie spacing and at different scaled distances. The results show that the response of columns is strongly dependent on scaled distance. As the scaled distance increased the severity of damage reduced; seismic columns showed better response. The effect of axial loading was also observed to increase the level of damage on reinforced concrete columns at the axial load level and blast loads considered in the test program.

Numerical Simulation of Air Shock Wave Propagation Effects in Reinforced Concrete Columns

2020 ◽  
Vol 12 (1) ◽  
pp. 12-22
Author(s):  
Ebrahim Akhlaghi
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Low Cost ◽  
Near Field ◽  
Research Work ◽  
Concrete Columns ◽  
Rc Columns ◽  
Reinforced Concrete Columns ◽  
Finite Element Package

Reinforced concrete has been shown to be a desirable material of choice in blast resistant structures due to its availability, relatively low cost, and its inherent ability to absorb energy produced by explosions. Most research work investigating the behaviour of reinforced concrete columns to blast loading have concentrated on their response to planar loading from far-field explosions. Limited amount of work is available on the effects of near-field explosion on the behaviour of reinforced concrete columns. This study is aimed to investigate effects of explosive loads on RC column by using ALE method. Commercial finite element package, LS-DYNA is used to simulate the behavior of blast wave on RC columns. Numerical simulation is validated against experimental work done in literature. The experience gained from this research provides valuable information for the development of the finite element modeling of real blast load effects on RC columns.

State of the art for enhancing the blast resistance of reinforced concrete columns with fiber-reinforced plastic

2013 ◽  
Vol 40 (11) ◽  
pp. 1023-1033 ◽  
Author(s):  
John E. Crawford
Keyword(s):  
Reinforced Concrete ◽  
Blast Resistance ◽  
Concrete Columns ◽  
Fiber Reinforced ◽  
Rc Columns ◽  
Reinforced Concrete Columns ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Residual Capacity ◽  
Bomb Threats

Protective design has become a chief concern in the design of some bridges and buildings, particularly related to the requirement that such facilities offer protection from accidental or malicious explosions. In this paper, the enhancement of the blast-resistance capability of reinforced concrete columns using FRP (fiber-reinforced plastic) is examined as a key element in upgrading the protective design of existing buildings and bridges. In this paper, the basic behaviors that need to be considered in blast effects analysis of RC columns for vehicle bomb threats are described. The ability of FRP to address these sorts of risks is shown through the analysis and test results presented. Three crucial points are made: (1) FRP offers a remarkable capability to enhance the blast resistance of existing RC columns, (2) assessing the residual capacity of large columns struck by a blast loading involves consideration of the effects of material damage, and (3) physics-based material models are often needed to capture the concrete behaviors engendered by intense blast loads.

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