scholarly journals Seismic Performance of Reinforced Concrete Short Columns Subjected to Freeze–Thaw Cycles

2019 ◽  
Vol 9 (13) ◽  
pp. 2708 ◽  
Author(s):  
Yixin Zhang ◽  
Shansuo Zheng ◽  
Xianliang Rong ◽  
Liguo Dong ◽  
Hao Zheng
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Shear Deformation ◽  
Seismic Performance ◽  
Shear Failure ◽  
Shear Capacity ◽  
Hysteretic Behavior ◽  
Freeze Thaw ◽  
Failure Patterns ◽  
Short Columns

Previous research shows that freeze–thaw cycles represent one of the most dangerous threats to reinforced concrete (RC) structures. However, there is almost no experimental data on the effects of freeze–thaw cycles on the seismic behavior of RC columns showing flexure-shear failure. In this study, three columns with the shear span-to-depth ratio of 2.5 were subjected to different numbers of freeze–thaw cycles (FTCs) and pseudo-static testing. The seismic performance indexes of the specimens were analyzed in terms of hysteretic behavior, skeleton curves, shear deformation, and energy dissipation. The test observations show that the failure patterns of the test columns altered from the flexure dominated to shear dominated, owing to the more severe deterioration in shear capacity induced by freeze–thaw attack than in flexure capacity. The test results also indicate that freeze–thaw cycles significantly decrease the ductility and energy dissipation of test columns, and they increase the contributions of shear deformation to the total deformation.

The Seismic Performance Analysis of Brick Masonry Wall between Windows with Central Reinforced Concrete Constructional Columns

2012 ◽  
Vol 193-194 ◽  
pp. 1221-1225
Author(s):  
Jing Yang ◽  
Wen Fang Zhang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Shear Failure ◽  
Reaction Force ◽  
Horizontal Displacement ◽  
Masonry Wall ◽  
Shear Capacity ◽  
Brick Masonry ◽  
Displacement Curve ◽  
Element Analysis

To research the seismic performance and failure mode of longitudinal independent brick masonry wall between or not between windows with setting central reinforced concrete constructional columns under the lateral function and vertical load, this paper used ABAQUS finite element analysis software to model the walls between or not between windows and be in stress analysis, obtaining the reaction force- displacement curve of loading location and the maximum horizontal displacement at the top of wall. Calculate and compare the shear strength and flexural capacity of walls. The results show that the brick masonry wall between windows with central constructional columns occurred shear failure, but the wall without windows occurred flexural failure. And compared with the wall between windows, the ductility increased, the shear capacity reduced and the seismic performance improved. Propose that can set up a isolated seam between the windowsill wall and longitudinal wall invented by Zhang Wenfang etc., and turn window wall to wall without windows to improve the seismic behavior of wall between windows.

scholarly journals Seismic Performance of High-Ductile Fiber-Reinforced Concrete Short Columns

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Mingke Deng ◽  
Yangxi Zhang
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Seismic Performance ◽  
Seismic Behavior ◽  
Fiber Reinforced Concrete ◽  
Test Results ◽  
Fiber Reinforced ◽  
Short Column ◽  
Short Columns

This study mainly aims to investigate the effectiveness of high-ductile fiber-reinforced concrete (HDC) as a means to enhance the seismic performance of short columns. Six HDC short columns and one reinforced concrete (RC) short column were designed and tested under lateral cyclic loading. The influence of the material type (concrete or HDC), axial load, stirrup ratio, and shear span ratio on crack patterns, hysteresis behavior, shear strength, deformation capacity, energy dissipation, and stiffness degradation was presented and discussed, respectively. The test results show that the RC short column failed in brittle shear with poor energy dissipation, while using HDC to replace concrete can effectively improve the seismic behavior of the short columns. Compared with the RC short column, the shear strength of HDC specimens was improved by 12.6–30.2%, and the drift ratio and the energy dissipation increases were 56.9–88.5% and 237.7–336.7%, respectively, at the ultimate displacement. Additionally, the prediction model of the shear strength for RC columns based on GB50010-2010 (Chinese code) can be safely adopted to evaluate the shear strength of HDC short 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 Influence of Patching on the Shear Failure of Reinforced Concrete Beam without Stirrup

2021 ◽  
Vol 6 (7) ◽  
pp. 97
Author(s):  
Stefanus Adi Kristiawan ◽  
Halwan Alfisa Saifullah ◽  
Agus Supriyadi
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Numerical Study ◽  
Unsaturated Polyester ◽  
Reinforced Concrete Beam ◽  
Concrete Cover ◽  
Shear Capacity ◽  
Rc Beam ◽  
Shear Span ◽  
Shear Cracking

Deteriorated concrete cover, e.g., spalling or delamination, especially when it occurs at the web of a reinforced concrete (RC) beam within the shear span, can reduce the shear capacity of the beam. Patching of this deteriorated area may be the best option to recover the shear capacity of the beam affected. For this purpose, unsaturated polyester resin mortar (UPR mortar) has been formulated. This research aims to investigate the efficacy of UPR mortar in limiting the shear cracking and so restoring the shear capacity of the deteriorated RC beam. The investigation is carried out by an experimental and numerical study. Two types of beams with a size of 150 × 250 × 1000 mm were prepared. The first type of beams was assigned as a normal beam. The other was a beam with a cut off in the non-stirrup shear span, which was eventually patched with UPR mortar. Two reinforcement ratios were assigned for each type of beams. The results show that UPR mortar is effective to hamper the propagation of diagonal cracks leading to increase the shear failure load by 15–20% compared to the reference (normal) beam. The increase of shear strength with the use of UPR mortar is consistently confirmed at various reinforcement ratios.

Seismic Performance of RC Short Columns Strengthened with BFRP

2013 ◽  
Vol 351-352 ◽  
pp. 1532-1536 ◽  
Author(s):  
Bin Ding ◽  
Li Jun Ouyang ◽  
Zhou Dao Lu ◽  
Wei Zhen Chen
Keyword(s):  
Seismic Performance ◽  
Failure Modes ◽  
Low Cost ◽  
Economic Cost ◽  
Shear Capacity ◽  
Good Prospect ◽  
Loading Test ◽  
Fiber Reinforced Plastic ◽  
Short Columns ◽  
Reinforced Plastic

BFRP has excellent strength, durability, thermal properties and economic cost. To test seismic performance of short columns strengthened with BFRP. Low cyclic loading test was conducted on one comparative short column and two RC short columns strengthened with BFRP. The test shows that short columns warped by BFRP show excellent failure modes, shear capacity, ductility and energy dissipation. As a new fiber reinforced plastic, BFRP has a good prospect in the area of seismic strengthening for its low cost and comprehensive mechanical properties.

Two-discrete-elements concrete shear deformation model: Formulation and application in the seismic evaluation of reinforced concrete shear walls

2020 ◽  
Vol 23 (16) ◽  
pp. 3429-3445
Author(s):  
Fadi Oudah ◽  
Raafat El-Hacha
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Deformation ◽  
Axial Load ◽  
Shear Deformation Theory ◽  
Shear Walls ◽  
Shear Capacity ◽  
Complex Nature ◽  
Deformation Model ◽  
Discrete Elements

Shear deformation in reinforced concrete structures is of a complex nature. A thorough understanding of the interaction between the shear strength, flexural strength, and flexural ductility is not yet achieved. A new shear-deformation-based theory is proposed and validated in this study. The so-called two-discrete-elements (TDE) shear deformation theory idealizes reinforced concrete members as series of two discrete types of elements: S-elements and C-elements. The S-elements are used to model the regions of concrete reinforced to resist flexural and shear deformation using longitudinal and transverse steel reinforcement, while the C-elements are used to model the reinforced concrete sections bounded by the stirrups. The compatibility between the two types of elements is enforced by controlling the crack angle. The formulation of the newly developed theory is discussed in terms of equilibrium of forces, compatibility within the elements, compatibility at the interface, and constitutive material modeling. The theory was applied to evaluate the deformability of reinforced concrete shear walls subjected to lateral loads for seismic design applications. It was also implemented to generate sample design charts referred to as axial–moment–shear interaction diagrams. These diagrams can be used to design shear walls subjected to combined action of axial load, moment, and shear as opposed to the conventional interaction diagrams in which only the axial load versus moment relationship is considered. Analysis results indicated the adequacy of the proposed theory in capturing the shear strength degradation and predicting structural failures controlled by the shear capacity.

scholarly journals Size Effect on the Seismic Performance of High-Strength Reinforced Concrete Columns with Different Shear Span-to-Depth Ratios

2018 ◽  
Vol 2018 ◽  
pp. 1-19
Author(s):  
Chunyi Yu ◽  
Hua Ma ◽  
Yongping Xie ◽  
Zhenbao Li ◽  
Zhenyun Tang
Keyword(s):  
Reinforced Concrete ◽  
Size Effect ◽  
Seismic Performance ◽  
Factor Of Safety ◽  
Shear Failure ◽  
High Strength ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
Local Factor ◽  
Shear Span

The size effect on the seismic performance of conventional reinforced concrete columns has been observed in terms of flexural failure and shear failure. Under earthquake loading, slender columns experience flexural failure, and short columns experience flexure-shear failure and shear failure. However, the effect of section size on the seismic performance of high-strength reinforced concrete columns under the conditions of different shear span-to-depth ratios requires further confirmation. For this purpose, six high-strength reinforced concrete columns with shear span-to-depth ratios of 2 and 4 were subjected to cyclic loading in this study. The experimental results indicated that relative nominal flexural strength, energy dissipation coefficient, factor of safety, and local factor of safety all exhibited a strong size effect by decreasing with increasing column size. Furthermore, the size effect became stronger as the shear span-to-depth ratio was increased, except for average energy dissipation coefficient. The observed changes in the factor of safety were in good agreement with the Type 2 size effect model proposed by Bažant. Thus, based on the local factor of safety and Bažant’s Type 2 model, the code equation for moment capacity of different shear span-to-depth ratios was modified to provide a consistent factor of safety regardless of column size.

Experimental Study on Seismic Performance of the Reinforced Concrete Grid-Mesh Frame Wall

2013 ◽  
Vol 680 ◽  
pp. 234-238
Author(s):  
Jin Li Qiao ◽  
Wen Ling Tian ◽  
Ming Jie Zhou ◽  
Fang Lu Jiang ◽  
Kun Zhao
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Bearing Capacity ◽  
Seismic Performance ◽  
Seismic Energy ◽  
Width Ratio ◽  
Filling Material ◽  
Energy Dissipation Capacity ◽  
Grid Mesh

In order to validate the seismic performance of reinforced concrete grid-mesh frame wall , four grid frame walls in half size is made with different height-width ratios and different grid forms in the paper. Two of them are filling with cast-in-place plaster as filling material. According to the experimental results of these four walls subjected to horizontal reciprocating loads, we know that the grid-mesh frame wall's breaking form are in stages and multiple modes, and the main influencing factors are height-width ratio and grid form, what's more, with cast-in-place plaster as fill material, could not only improve the level of the wall bearing capacity and stiffness, but also improve the ductility and seismic energy dissipation capacity.

Seismic Rehabilitation of Beam-Column Joints Using FRP Sheets and Buckling Restrained Braces

2013 ◽  
Vol 479-480 ◽  
pp. 1170-1174
Author(s):  
Hee Cheul Kim ◽  
Dae Jin Kim ◽  
Min Sook Kim ◽  
Young Hak Lee
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Seismic Performance ◽  
Reinforced Concrete Structures ◽  
Test Results ◽  
Seismic Rehabilitation ◽  
Buckling Restrained Braces ◽  
Column Joint ◽  
Energy Dissipation Capacity

The purpose of this study was to evaluate seismic performance of rehabilitated beam-column joint using FRP sheets and Buckling Restrained Braces (BRBs) and provide test data related to rehabilitated beam-column joints in reinforced concrete structures. The seismic performance of total six beam-column specimens is evaluated under cyclic loadings in terms of shear strength, effective stiffness, energy dissipation and ductility. The test results showed wrapping FRP sheets can contribute to increase the effect of confinement and the crack delay. Also retrofitting buckling restrained braces (BRBs) can improve the stiffness and energy dissipation capacity. Both FRP sheets and BRBs can effectively improve the strength, stiffness and ductility of seismically deficient beam-column joints.

Analysis of seismic performance and research of load capacity of steel reinforced high strength concrete columns with rectangular helical hoops

2020 ◽  
pp. 136943322098165
Author(s):  
Jianyang Xue ◽  
Xin Zhang ◽  
Xiaojun Ke
Keyword(s):  
Failure Mode ◽  
Seismic Performance ◽  
Calculation Method ◽  
High Strength Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
High Strength ◽  
Shear Capacity ◽  
Strength Concrete ◽  
Shear Span

This paper mainly focused on the seismic performance and shear calculation method of steel reinforced high-strength concrete (SRHC) columns with rectangular helical hoops. An experimental investigation was performed in this paper. Eleven SRHC columns with rectangular helical hoops and one with ordinary hoops were constructed at the laboratory of Guangxi university. The failure modes, hysteresis loops, envelope curves, characteristic loads and displacements and cumulative damage analysis are presented and investigated. It can be seen from the test results that the failure modes of SRHC columns can be divided into three types with the shear span ratio increased, namely, shear baroclinic failure mode, flexure-shear failure mode and flexure failure mode. In addition, the specimens with rectangular helical hoops have plumper hysteretic loops. Shear span ratio is the main influencing factor of characteristic load; the axial compression ratio and concrete strength have less influence on characteristic load, while stirrup ratio has little effect on the characteristic load. Finally, a calculation method for shear capacity of SRHC columns under shear baroclinic failure and flexure-shear failure mode is proposed.

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