On lap splice length of lap-spliced crossties for reinforced concrete columns under cyclic loading

2020 ◽  
Vol 23 (12) ◽  
pp. 2669-2678
Author(s):  
Tai-Kuang Lee ◽  
Cheng-Cheng Chen
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Concrete Columns ◽  
Seismic Resistance ◽  
Reinforced Concrete Column ◽  
Reinforced Concrete Columns ◽  
Lap Splice ◽  
Concrete Confinement ◽  
Confining Effect

A lap-spliced crosstie comprises two J-shaped rebars, each with a 180° hook at one end and straight at the other end. Six large reinforced concrete columns subjected to lateral cyclic loading were tested. The results indicated the following: (1) the confining effect of horizontally lap-spliced crossties is similar to that of vertically lap-spliced crossties. (2) Splice length of the lap-spliced crossties that is smaller than the code requirement can also provide sufficient concrete confinement. (3) A method for determining required lap splice length for lap-spliced crossties is proposed. (4) The lap-spliced crosstie can considerably improve the constructability of the crossties. Furthermore, the construction quality of reinforced concrete column reinforcement and the seismic resistance capability of reinforced concrete structures can be significantly upgraded.

SEISMIC PERFORMANCE OF GFRP-RC RECTANGULAR COLUMNS: NUMERICAL STUDY

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ehab El-Salakawy ◽  
Fangxin Ye ◽  
Yasser Mostafa Selmy
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Axial Load ◽  
Numerical Study ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Concrete Columns ◽  
Load Level ◽  
Reinforced Concrete Columns ◽  
Rectangular Columns

Composite materials like glass fiber-reinforced polymer (GFRP) is becoming widely acceptable to be used as a reinforcing material due to its high ultimate tensile strength-to-weight ratio and excellent resistance to corrosion. However, the seismic behavior of GFRP-reinforced concrete columns has not been fully investigated yet. This paper presents the results of a numerical analysis of full-size GFRP-RC rectangular columns under cyclic loading. The simulated column depicts the lower part of a building column between the foundation and the point of contra-flexure at the mid-height of the column. GFRP reinforcement properties and concrete modeling based on fracture energy have been incorporated in the numerical model. Experimental validation has been used to examine the accuracy of the constructed finite element models (FEMs) using a commercially available software. The validated FEM was used to perform a parametric study, considering several concrete strength values and axial load levels, to study its influence on the performance of the GFRP-reinforced concrete columns under cyclic loading. It was concluded that the hysteretic dissipation capacity deteriorates under high axial load level due to severe softening of the concrete. The FE results showed a substantial improvement of the lateral load-carrying capacities by increasing concrete compressive strength.

scholarly journals Gravity Load Collapse Behavior of Nonengineered Reinforced Concrete Columns

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Chichaya Boonmee ◽  
Kittipoom Rodsin ◽  
Krissachai Sriboonma
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Axial Load ◽  
Concrete Columns ◽  
Poor Quality ◽  
Load Level ◽  
Longitudinal Reinforcement ◽  
Reinforced Concrete Columns ◽  
Gravity Load ◽  
Collapse Behavior

This paper aims at investigating gravity load collapse behavior of extremely poor quality reinforced concrete columns under cyclic loading. Such columns were usually constructed by local people and may not be designed to meet any of the standards. It was found that their concrete strength may be as low as 5 MPa and the amount of longitudinal reinforcement may be lower than 1%. This type of column is deliberately defined as “nonengineered reinforced concrete column,” or NRCC. During earthquake, the gravity load collapse of the NRCC columns caused a large number of death tolls around the world. In this study, four columns as representative of existing NRCC were tested under cyclic loading. The compressive strength of concrete in order of 5 MPa was used to be representative of columns with poor quality concrete. Two axial load levels of 6 and 18 tons were used to study the influence of axial load level on maximum drift at gravity load collapse. To investigate the effect of bar types on drift capacity, 9 mm round bars were used in two specimens and 12 mm deformed bars were used for the rest of the specimens. The maximum drift before gravity load collapse was very dependent on the axial load level. The maximum drift of the specimens subjected to high axial load (18 tons) was extremely low at approximately 1.75% drifts. The use of deformed bars (associated with larger amount of longitudinal reinforcement) caused the damage to severely dissipate all over the height of the columns. Such damage caused columns to collapse at a lower drift compared to those using round bars. Finally, the plastic hinge model was used to predict the maximum drift of the low strength columns. It was found that the model overly underestimates the drift at gravity load collapse.

Cyclic loading test for reinforced concrete columns with continuous rectangular and polygonal hoops

2014 ◽  
Vol 67 ◽  
pp. 39-49 ◽  
Author(s):  
Tae-Sung Eom ◽  
Su-Min Kang ◽  
Hong-Gun Park ◽  
Tae-Woo Choi ◽  
Jong-Min Jin
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Concrete Columns ◽  
Loading Test ◽  
Reinforced Concrete Columns ◽  
Cyclic Loading Test

Retrofit of Concrete Columns with Inadequate Lap Splices by the Use of Rectangular Steel Jackets

1996 ◽  
Vol 12 (4) ◽  
pp. 693-714 ◽  
Author(s):  
Riyad S. Aboutaha ◽  
Michael D. Engelhardt ◽  
James O. Jirsa ◽  
Michael E. Kreger
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Concrete Columns ◽  
Seismic Retrofit ◽  
Design Guidelines ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Columns ◽  
Lap Splice ◽  
Concrete Frame ◽  
Anchor Bolts

This paper describes an experimental research program on the use of rectangular steel jackets for seismic retrofit of non-ductile reinforced concrete frame columns. Eleven large scale columns were tested to examine the effectiveness of various types of steel jackets for improving the ductility and strength of columns with an inadequate lap splice in the longitudinal reinforcement. Response of the columns before and after being strengthened with steel jackets was examined. Several types of steel jackets were investigated, including rectangular solid steel jackets with and without adhesive anchor bolts. The test results indicate that a thin rectangular steel jacket combined with adhesive anchor bolts can be a highly effective retrofit measure for reinforced concrete columns with an inadequate lap splice. Design guidelines for the use of rectangular steel jackets as a seismic retrofit for non-ductile reinforced concrete columns are presented.

Sign in / Sign up

Export Citation Format

Share Document