An experimental study of the axial compression performance of two-part precast concrete columns

2021 ◽  
pp. 136943322110159
Author(s):  
Bo Wu ◽  
Zhikai Wei
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Axial Load ◽  
Precast Concrete ◽  
Concrete Columns ◽  
Longitudinal Reinforcement ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Compression Performance ◽  
Waste Concrete

Recycled lump concrete (RLC) made with demolished concrete lumps (DCLs) and fresh concrete (FC) provides a solution for effective waste concrete recycling. To promote the development of precast RLC structures, this study tested a new type of connection for precast concrete columns: connecting the upper and the lower halves of columns with bent longitudinal reinforcements and structural adhesive. In this work the behavior of precast RLC columns with the new connection was studied under axial compression. The axial compressive strength of nine two-part columns was tested. The effects of the degree of bending in the longitudinal reinforcement, the replacement ratio of DCLs and the stirrup spacing were investigated. Tests showed that: (1) the failure mode of precast concrete columns is different from that of cast-in-place columns; (2) when the strength of the waste concrete is close to that of the fresh material, there is no significant difference in the axial compression performance of either precast or cast-in-place columns; (3) the bent longitudinal reinforcement causes the axial load bearing capacity of precast concrete columns to be 4.2%–12.3% lower than that of a similar cast-in-place column; (4) reducing the stirrup spacing has little effect on a precast column’s axial load bearing capacity and ductility; (5) when using Chinese and American codes to predict the axial load bearing capacity of the column, the predicted value should be multiplied by a reduction factor.

scholarly journals EVALUATION OF AXIAL LOAD-BEARING CAPACITY OF CONCRETE COLUMNS STRENGTHENED BY A NEW SECTION ENLARGEMENT METHOD

2021 ◽  
Vol 0 (0) ◽  
pp. 1-14
Author(s):  
Meijing Hao ◽  
Wenzhong Zheng ◽  
Wei Chang
Keyword(s):  
Bearing Capacity ◽  
Axial Load ◽  
Large Scale ◽  
Prediction Models ◽  
Concrete Columns ◽  
High Accuracy ◽  
Confining Stress ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Compressive Loads

The objective of this study is to evaluate the axial load-bearing capacity of section-enlargement concrete columns. To reach the objection, a new strengthened method in which columns are jacketed with a large welded octagonal stirrup at the center and four spiral stirrups at the corners of column is developed. The new section-enlargement method avoids interrupting existing columns and improves the reliability of strengthened part, besides, the confining stress generated by octagonal stirrup and spiral stirrups enhances the compressive strength and deformability of strengthened columns. In addition, sixteen large-scale concrete columns strengthened by the new strengthened method were tested under axial compressive loads. The experimental results show that the axial compression ratio of existing column generates stressstrain lag in strengthened part and decreases the load-bearing capacity of specimens; the stirrups in strengthened part significantly enhance the axial load-bearing capacity of specimens. According to confinement conditions, the cross-section of specimens is divided into five parts and the confinement factor for each part is calculated to establish the prediction models for the load-bearing capacity of specimens. Furthermore, by comparing the results between the developed model and existing models, the developed model has high accuracy in evaluating the load-bearing capacity of strengthened columns.

Experimental Research on Behavior of CFRP Circular Steel Tubular Confined Recycled Aggregate Concrete Columns under Axial Compression

2015 ◽  
Vol 744-746 ◽  
pp. 96-99
Author(s):  
Jiong Feng Liang ◽  
Ze Ping Yang ◽  
Ming Hua Hu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Concrete Columns ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Compression Tests ◽  
Load Bearing Capacity ◽  
Aggregate Concrete ◽  
Load Bearing ◽  
Cfrp Wrapping

In order to further promote the use of recycled aggregate concrete in practice, axial compression tests were carried out for 7 CFRP circular steel tubular confined recycled aggregate concrete columns. The influence of the replace rate of recycled aggregate concrete, the wrapping method on axial compression behavior of CFRP circular steel tubular confined recycled aggregate concrete columns were analyzed. Based on the results of the tests, with the replace rate of recycled aggregate concrete increasing, the specimens have an decreasing trend in the load bearing capacity. The whole CFRP wrapping circular steel tubular confined recycled aggregate concrete columns have higher load bearing capacity than the three stripe wrapping ones.

Experimental Study on Axial Compression Performance of Full-Scale Square Columns of Reinforced Concrete Confined by High-Strength Reinforcement Hoops

2012 ◽  
Vol 446-449 ◽  
pp. 981-988
Author(s):  
Zhen Bao Li ◽  
Wen Jing Wang ◽  
Wei Jing Zhang ◽  
Yun Da Shao ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Bearing Capacity ◽  
Axial Compression ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Full Scale ◽  
Compression Performance ◽  
Deformation Ability

Axial compression experiments of four full-scale reinforced concrete columns of two groups were carried out. One group of three columns used high-strength steel with the yield strength of 1000MPa as reinforcement hoops, and the second group used the ordinary-strength steel with yield strength of 400MPa. The axial compressive performances between these two groups were assessed. Compared to the specimen using the ordinary-strength steel, the axial compressive bearing capacity of using the high strength steel dose not increase significantly, while the deformation ability increases greatly. The results also indicate that the stress redistributions of the hoops and the concrete sections are obvious, and long-lasting when specimens achieve the ultimate bearing capacity after the yield of the rebar and local damage of concrete materials, at this time the strain of the specimens developes a lot, especially stress - strain curves of speciments with high-strength hoop all show a wide and flat top.

Experimental Study on All-Lightweight Aggregate Concrete Columns under Eccentric Loading

2012 ◽  
Vol 517 ◽  
pp. 392-397
Author(s):  
Yan Min Yang ◽  
Hao Zhang
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Lightweight Aggregate ◽  
Concrete Columns ◽  
Lightweight Aggregate Concrete ◽  
Fine Aggregate ◽  
Mechanical Behaviors ◽  
Load Bearing Capacity ◽  
Aggregate Concrete ◽  
Load Bearing

A kind of lightweight sand was only used as the fine aggregate to make the all-lightweight aggregate concrete, which can significantly reduce the gravity load of a structure and the foundation loads. Accordingly, the application of all-lightweight aggregate concrete in the construction projects can reduce the cost of foundation as well as construction project. In order to develop a new multi-story structural system which has a multifunction of load-bearing, lightweight and energy saving, the paper carried out an experimental study on the mechanical behaviors of six all-lightweight aggregate concrete columns with symmetrical reinforcement under eccentric loading. The failure modes, deformation characteristics and load-bearing capacity of the columns were analyzed. The effect of reinforcement ratio, stirrup ratio and eccentricity on the mechanical behaviors of the columns under eccentric loading were discussed. The test results show that all-lightweight aggregate concrete columns were loaded to failure with high load-bearing capacity and good ductility. The excellent mechanical behavior and the possibility of replacing the normal concrete with all-lightweight aggregate concrete were verified.

Experimental Study on the Mechanical Properties of Reinforced Concrete Columns after Exposure to Fire

2011 ◽  
Vol 243-249 ◽  
pp. 5122-5127
Author(s):  
Jia Feng Xu ◽  
Ming Zhe Liu ◽  
Yue Feng Tang
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Room Temperature ◽  
Ultimate Load ◽  
Concrete Columns ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing

This paper provided three test data pertaining to the mechanical properties of reinforced concrete columns after exposure to ISO834 standard fire and three comparative test data pertaining to the mechanical properties of reinforced concrete columns at room temperature, mainly concerning the influence of fire on failure mode, distortion performance and ultimate load bearing capacity of reinforced concrete columns under axial and eccentric compression. Test results show that the failure mode of reinforced concrete columns after exposure to fire is basically same with that at room temperature. With the same concrete strength and heating condition, the bearing capacity of specimens reduces as the eccentricity increases. Strain along the section height of eccentric columns after fire basically agree with the plane section supposition while the flexural rigidity and ultimate load bearing capacity decreases obviously. The residual load bearing capacity of reinforced concrete columns after exposure to fire is only about 25% to 37% of that at room temperature.

The Study of Post-Fire Load Bearing Capacity of Steel Column under Axial Compression Exposure to one-Side Fire

2011 ◽  
Vol 284-286 ◽  
pp. 330-334
Author(s):  
Jian Feng Chen ◽  
Tian Hua Zhou ◽  
Lin Feng Lu ◽  
Han Heng Wu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Load Condition ◽  
Heterogeneous Material ◽  
Material Strength ◽  
Fire Load ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Steel Column ◽  
Uniform Temperature Field

The section of steel column under axial compression presents heterogeneous material and its load condition changes after experiencing fire damage of one side. Taking H-section steel column under axial compression commonly used in engineering for study object in this thesis in order to study post-fire residual load bearing capacity, the post-fire eccentric effect of steel column under axial compression exposure to one-side fire is analyzed using the method of equivalent section which considering the change of the material strength after high temperature, the influence of non-uniform temperature field on material properties and the stiffness degradation of member section. Calculation methods of the eccentricity and additional moment are proposed and further given a formula of residual load bearing capacity.

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