scholarly journals Effect of Low-Level Cyclic Loading on Bond Behavior of a Steel Bar in Concrete with Pre-Existing Damage

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7080
Author(s):  
Chongku Yi ◽  
Jeeho Lee ◽  
Kee-Jeung Hong

Understanding the bond behavior of steel rebar in concrete is important in order to determine the performance of a reinforced concrete structure. Although numerous studies have been carried out by many researchers to develop a robust model for numerical analysis, no consensus has been reached as the bond behavior depends on hysteresis. In this study, the bond behavior of a steel bar in concrete with pre-existing damage is investigated under low-level cyclic loading. Based on the experimental bond stress and slip curve, a numerical model for finite element analysis to simulate the effect of low-level cyclic loading is proposed. The results from the numerical analysis show good agreement with the experimental data, including accumulated damage on stiffness and strength throughout entire load cycles.

2011 ◽  
Vol 71-78 ◽  
pp. 898-902
Author(s):  
Yuan Qing Wang ◽  
Jong Su Sung ◽  
Yong Jiu Shi

Composite slab with steel sheeting deck is considered a continuous slab when it is under a constructional situation. Nevertheless, many recent researches are focused on simply supported slab. In order to determine the load carrying capacity regarding various rebar ratio on negative moment region, a numerical analysis was carried out by using finite element analysis. The result of analysis shows that the reinforced steel rebar increases load carrying capacity. Moreover, it has shown that the reinforced length of steel rebar also affect the load carrying capacity.


2016 ◽  
Vol 51 (7) ◽  
pp. 913-925 ◽  
Author(s):  
MY Matveev ◽  
AC Long ◽  
LP Brown ◽  
IA Jones

Experimental and numerical analyses of a woven composite were performed in order to assess the effect of yarn path and layer shift variability on properties of the composite. Analysis of the geometry of a 12 K carbon fibre 2 × 2 twill weave at the meso- and macro-scales showed the prevalence of the yarn path variations at the macro-scale over the meso-scale variations. Numerical analysis of yarn path variability showed that it is responsible for a Young’s modulus reduction of 0.5% and CoV of 1% which makes this type of variability in the selected reinforcement almost insignificant for an elastic analysis. Finite element analysis of damage propagation in laminates with layer shift showed good agreement with the experiments. Both numerical analysis and experiments showed that layer shift has a strong effect on the shape of the stress–strain curve. In particular, laminates with no layer shift tend to exhibit a kink in the stress–strain curve which was attributed solely to the layer configuration.


2011 ◽  
Vol 243-249 ◽  
pp. 948-952
Author(s):  
Hui Mao ◽  
Yan Wang ◽  
Cheng Hua Li

Based on the experiments of four connections with widened beam flange section which included two arc widened beam flange connections and two welded side-plate connections specimens and one ordinary connection under cyclic loading, 3-D nonlinear finite element models were created by using ANSYS software to analyze the mechanical properties of these two types of widened beam flange connections, such as skeleton curve, ultimate load, ductility and failure mode etc. The analytical results show good agreement with those of the experiments and prove the finite models correct and applicable. According to the experimental and element analytical failure results, the PI(PEEQ Index) was introduced to investigate the plasticity development and fracture tendency at the end of the widened flange part . Furthermore, the failure patterns of widened beam flange connection were revealed.


2021 ◽  
Vol 60 (1) ◽  
pp. 853-861
Author(s):  
Tian Su ◽  
Ting Wang ◽  
Haihe Yi ◽  
Rui Zheng ◽  
Yizhe Liu ◽  
...  

Abstract In this article, the ABAQUS finite element software is used to simulate the bond behavior of the steel bar in salt–frost-damaged recycled coarse aggregate concrete, and the influence of the steel bar diameter and the concrete cover thickness on the bond strength is investigated. The result shows that the calculated bond–slip curve is in good agreement with the experimental bond–slip curve; the mean value of the ratio of the calculation results of ultimate bond strength to the experiment results of ultimate bond strength is 1.035, the standard deviation is 0.0165, and the coefficient of variation is 0.0159, which proves that the calculation results of the ultimate bond strength are in good agreement with the experimental results; with the increase of steel bar diameter and the concrete cover thickness, the ultimate bonding strength of RAC and steel increases; the calculation formulas for the ultimate bond strength of specimens with different steel bar diameters (concrete cover thickness) after different salt–frost cycles are obtained.


2019 ◽  
Vol 972 ◽  
pp. 26-33
Author(s):  
Muhammad Harunur Rashid ◽  
Md. Maruf Molla ◽  
Imam Muhammad Taki

In the case of exposure of reinforced concrete structure to accidental fire, an assessment of its residual capacity is needed. Bond strength of concrete was observed under elevated temperatures (150°, 250°, 350° and 500°C) in this study. Cylindrical specimens were prepared for pull-out tests to find out the bond behavior and to observe the mechanical properties of concrete. All the specimens were 100 mm diameter and 200 mm height. The pull-out specimens contain a 10 mm steel bar at its center. The specimens were tested at 52 days age following a 28 days water curing. Samples were preheated for 3 hours at 100°C temperature and then put into the furnace for 1 hour at the target temperature. Samples were tested before preheating as controlled specimens. In case of mechanical properties and the bond strength of concrete, there were no remarkable changes due to elevated temperature up to 150°C. However, the mechanical properties and bond strength were decreased gradually after 150°C temperature. Maximum reduction of bond strength observed was 52.13% and 49.8% at 500°C for testing within 1 hour and after 24 hours of heating respectively when compared to the controlled specimens. Bond strength was found to reduce at a greater rate than compressive strength due to the elevated temperature.


2012 ◽  
Vol 166-169 ◽  
pp. 287-291 ◽  
Author(s):  
Qing Jun Chen ◽  
Jin Long Guo ◽  
Jian Cai ◽  
An He ◽  
Xu Lin Tang ◽  
...  

Concrete filled steel tubular (CFST) column-beam joint with the column tube discontinuous in joint zone is a new type of joint. Firstly, the results of the cyclic loading experiments on this joint were introduced briefly. Then numerical simulation of the experiment process was carried out by OPENSEES, and the load-displacement curves, strength degradation, stiffness degradation of the specimens were studied. The analysis results exhibit good agreement with the experimental ones. OPENSEES can simulate two types of failure, including joint failure and beam failure. Based on specimen S3, parametric analysis were conducted to research the strength degradation and stiffness degradation in models with different reinforcement ratios and reinforcement diameters. The results indicate that models with higher reinforcement ratio of the beams will result in joint failure under cyclic reverse loading, and their load-displacement curves are pinched and ultimate bearing capacity would not increase while strength degradation and stiffness degradation would appear obviously.


2013 ◽  
Vol 838-841 ◽  
pp. 53-56
Author(s):  
Yun Tao Zhang

The finite element software ANSYS/CivilFEM was applied to analyses the influence of steel bar restraint on creep and shrinkage of reinforced concrete. The analysis results are in good agreement with the experiment results. When the reinforcement ratio is low, the steel bar exerts less influence on creep and shrinkage, and the influence of steel bar can be neglected in engineering application. However, the reinforcement can effectively reduce creep and shrinkage development when the reinforcement ratio is high.


Author(s):  
Zih-Yu Lai ◽  
Yan-Fang Liu ◽  
Ching-Ching Yu ◽  
Juin-Fu Chai ◽  
Fan-Ru Lin ◽  
...  

According to the seismic risk assessment results presented in the Final Safety Analysis Report (FSAR) for a nuclear power plant in Taiwan, the failure of Residual Heat Removal (RHR) piping system occurs in both of the two accident sequences with the highest contributions for core damage. The seismic performance of RHR piping system depends on the capacity of its components, such as supports, flanged joints and reducers. For the need of seismic response-history analysis of RHR piping systems, we developed detailed numerical models of flanged joint and reducer using finite element analysis software (ABAQUS and SAP2000). The proposed finite element models were verified by the experimental results. The pure bending tests with four-point cyclic loading were conducted for sample flanged joint and reducer to investigate their mechanical behaviors. The displacement and rotation responses identified from the tests are in good agreement with the results of numerical analysis. A preliminary simplified model of flanged joints was also proposed in this study to improve the efficiency of numerical analysis for RHR piping system.


1989 ◽  
Vol 17 (2) ◽  
pp. 86-99 ◽  
Author(s):  
I. Gardner ◽  
M. Theves

Abstract During a cornering maneuver by a vehicle, high forces are exerted on the tire's footprint and in the contact zone between the tire and the rim. To optimize the design of these components, a method is presented whereby the forces at the tire-rim interface and between the tire and roadway may be predicted using finite element analysis. The cornering tire is modeled quasi-statically using a nonlinear geometric approach, with a lateral force and a slip angle applied to the spindle of the wheel to simulate the cornering loads. These values were obtained experimentally from a force and moment machine. This procedure avoids the need for a costly dynamic analysis. Good agreement was obtained with experimental results for self-aligning torque, giving confidence in the results obtained in the tire footprint and at the rim. The model allows prediction of the geometry and of the pressure distributions in the footprint, since friction and slip effects in this area were considered. The model lends itself to further refinement for improved accuracy and additional applications.


2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.


Sign in / Sign up

Export Citation Format

Share Document