Local Reinforcing of RC Columns by Steelwork: A Parametric Study

Author(s):  
Antonio Formisano
Keyword(s):  
Author(s):  
Deok-Hee Won ◽  
Taek-Hee Han ◽  
Jung-Hun Kim ◽  
Jun-Ho Choi ◽  
Young-Jong Kang

2020 ◽  
Vol 20 (03) ◽  
pp. 2050029
Author(s):  
Jian Weng ◽  
Kang Hai Tan ◽  
Chi King Lee

A simple solution method to identify buckling resistance of reinforced concrete (RC) columns during inelastic deformation is presented. Unlike conventional buckling solution methods, this proposed method predicts inelastic buckling loads of RC columns by directly solving the equilibrium differential equation under buckling. The method considers specific deflection configuration, end restraint conditions and inelastic material properties of the deformed column. In order to evaluate the reliability and accuracy of the proposed method, the results obtained from the purposed method are compared with the test results of eccentrically loaded RC columns. In addition, by using the proposed solution procedure, a parametric study is conducted to investigate the effects of critical RC column design parameters on column buckling behavior and resistance, including slenderness ratio, concrete strength, as well as longitudinal reinforcement and stirrup ratios. The results of the parametric study show that the proposed method is rational and can be adopted to effectively identify buckling resistance of RC columns subjected to inelastic damage, especially when load redistributions have occurred in the structure during progressive collapse.


2021 ◽  
Author(s):  
Ahmed Younus ◽  
◽  
Haider Hekmet ◽  
Abeer Al-Shami ◽  
◽  
...  

As one of the most important topics that have not been sufficiently studied to investigate the structural behavior of concrete columns is the mechanical properties of concrete members resulting from the torsional effects that caused mainly from the exposure of buildings to earthquakes, especially the cracks resulting in the structural members and overall torque-twist behavior. However, concrete columns are elements that are difficult to replace when exposed to earthquakes, so the role of developing applicable and useful methods for maintaining and strengthening columns has emerged after exposure to torsion. FRP laminates like CFRP and GFRP are one of the most successful and widespread of these methods nowadays. To achieve the goal of this paper, a finite element 3D model suitable for analyzing square RC columns strengthened with GFRP under combined torsional moment and axial loads has been adopted and a reasonable method for calculating angles of twist for square concrete columns using the finite element method has been developed. [ANSYS] software as a useful tool is used to solve the problem and to predict the Torque – Twist relationships of the columns under investigation. The results are compared and verified with an experimental study and the numerical results showed acceptable agreement with the experimental results. Several important parameters affecting the torsional capacity of square columns strengthened with GFRP and subjected to combined torque & axial load are studied in parametric study. These parameters include, GFRP distribution, GFRP thickness, and GFRP schemes (orientation). The results showed the efficiency of finite element software to estimate the torque twist relationships after developing modified formulas to calculate the angles of twist, on the other hand, the fixing of GFRP sheets in 45 degree opposite to the cracks orientation is the best way to increase the torsional capacity of RC columns.


2020 ◽  
Vol 2 (1) ◽  
pp. 19-24
Author(s):  
Sakhr Mohammed Sultan ◽  
Chih Ping Tso ◽  
Ervina Efzan Mohd Noor ◽  
Fadhel Mustafa Ibrahim ◽  
Saqaff Ahmed Alkaff

Photovoltaic Thermal Solar Collector (PVT) is a hybrid technology used to produce electricity and heat simultaneously. Current enhancements in PVT are to increase the electrical and thermal efficiencies. Many PVT factors such as type of absorber, thermal conductivity, type of PV module and operating conditions are important parameters that can control the PVT performance. In this paper, an analytical model, using energy balance equations, is studied for PVT with an improved parallel flow absorber. The performance is calculated for a typical sunny weather in Malaysia. It was found that the maximum electrical and thermal efficiencies are 12.9 % and 62.6 %, respectively. The maximum outlet water temperature is 59 oC.


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