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.

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.

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.

Experimental Research and Finite Element Analysis on the Axial Pressure Bearing Capacity of Steel skeleton-Steel Pipe Reinforced Composite Concrete Columns

2012 ◽  
Vol 204-208 ◽  
pp. 995-998
Author(s):  
Yun Yun Li ◽  
Bao Sheng Yang
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Concrete Columns ◽  
Steel Pipe ◽  
Axial Pressure ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Load Bearing ◽  
Finite Element Software ◽  
Reinforced Composite

This paper studies the working mechanism, ductility, and ultimate load bearing capacity of the composite columns through axial load bearing capacity experiments on eight steel skeleton-steel pipes reinforced composite concrete columns. The results show that the collaborative work between the steel pipe, steel skeleton and concrete can effectively improve the bearing capacity of the column, delay or inhibit the spread of shear diagonal cracks in the concrete and improve the ductility of the column. In addition, the finite element software ANSYS is used to digitally simulate the whole process of axial pressure test, and the resulting load-displacement curves and experimental curves agree fairly well.

scholarly journals FLEXURAL CAPACITY OF CORRODED POST-TENSIONED CONCRETE BEAMS: LARGE SCALE TESTS AND NUMERICAL SIMULATION

2020 ◽  
Author(s):  
Antonino Recupero ◽  
Nino Spinella ◽  
Antonio Marì ◽  
Jesús Miguel Bairan
Keyword(s):  
Numerical Model ◽  
Bearing Capacity ◽  
Large Scale ◽  
Concrete Beams ◽  
Structural Response ◽  
Experimental Results ◽  
Analysis Model ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Post Tensioned

An experimental campaign on corroded post-tensioned concrete beams is being carried out at the University of Messina (Italy). The main goal of the research project is to study the influence of the tendon corrosion on the response behaviour of post-tensioned concrete beams subjected to a transversal load. In 2006, six beams were cast with a tendon placed at the centroid of the cross-section. Corrosion of the tendons was artificially induced in each specimen by injecting a chemical solution or an acid in some parts of the duct. The experimental results have showed how external causes, reproduced by artificial defects, can induce several critical issues, and undermine both the durability and the load bearing capacity of the beams. The load bearing capacity of the beam with defects was reduced until half of the one recorded for the specimen with not corroded tendon. In addition, a non-linear and time dependent analysis model, developed at UPC in Barcelona, was used to simulate the response of the tested beams, with the purpose of experimentally verifying the capacity of the model to capture the effects of corrosion along the time. A parametric study was performed with the numerical model to capture the influence of the degree of corrosion, (defined as the % loss of steel mass) on the serviceability response and on the ultimate capacity. By comparing the theoretical and the experimental results, the degree of corrosion was estimated and compared with that observed subsequently on the tested beams. Good correlation was obtained, thus allowing the numerical model to be used as a “virtual lab” to study the influence of several parameters on the structural response of corroded post-tensioned beams.

Research on the Mechanical Properties of Fire-Damaged Reinforced Concrete Columns Strengthened with CFRP

2012 ◽  
Vol 193-194 ◽  
pp. 1429-1435
Author(s):  
Dong Liang Qiu ◽  
Kai Yu ◽  
Guo Feng Wang ◽  
Jun Hua Li
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Temperature Control ◽  
Concrete Columns ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing ◽  
Standard Fire ◽  
Reinforced Polymer

The mechanical properties of fire-damaged reinforced concrete columns rehabilitated by carbon fiber-reinforced polymer (CFRP) rods were studied. This study aims at the effectiveness of CFRP through the contrast test. Nine specimens were tested, including three normal temperature control specimens, and six specimens heated under ISO834 standard fire. After the specimens were exposed to fire, three of them were rehabilitated by CFRP. All specimens were loaded monotonically to failure in the same way. The results showed that the failure of reinforced concrete columns rehabilitated by CFRP was due to losing stabilization, whereas the others were material broken. Furthermore, because of the fire, the load-bearing capacity of specimens was all declined sharply compared with these at normal temperature. From this research, comparing with these normal temperature control specimens, the load-bearing capacity of specimens exposed to fire firstly was ranged from 0.25 to 0.37 times. But the ratio of the loading capacity of specimens rehabilitated by CFRP and normal temperature control ones was ranged from 0.54 to 0.67.

ARE TIBIOFEMORAL COMPRESSIVE LOADS TRANSFERRED ONLY VIA CONTACT MECHANISMS?

2012 ◽  
Vol 12 (04) ◽  
pp. 1250071
Author(s):  
FERAS HAKKAK ◽  
MOSTAFA ROSTAMI ◽  
MOHAMAD PARNIANPOUR
Keyword(s):  
Bearing Capacity ◽  
Contact Stress ◽  
Contact Area ◽  
Daily Activities ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Tibiofemoral Joint ◽  
Body Weights ◽  
Compressive Loads ◽  
Joint Loads

The tibiofemoral joint is known to bear compressive loads of several body-weights during daily activities. These forces are known to be transferred through the joint via compression of the tibial and femoral surfaces against one another. The menisci are also known to enhance this process by increasing the contact area and decreasing contact stress. However, calculations presented in this paper suggest that the load-bearing capacity of contact mechanisms is seemingly several times smaller than tibiofemoral joint loads. This suggests that probably one or more non-contact load-bearing mechanism(s) exist, and share the load with the already known contact mechanisms.

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