Evaluation of Torsional Capacity of Square RC Columns Strengthened with CFRP Using Finite Element Modeling
American Journal of Civil Engineering
Volume 1, Issue 3, November 2013, Pages: 111-123
Received: Oct. 7, 2013;
Published: Nov. 10, 2013
Views 3120 Downloads 257
Ahmed Sameer Younus, Structural Engineering, Civil Engineering Department, Al Nahrain University, Baghdad, IRAQ
Ammar A. Abdul Rahman, Structural Engineering, Faculty Member, Civil Engineering Department, Al Nahrain University, Baghdad, IRAQ
Researches on behavior of reinforced concrete (RC) columns subjected to torsion including mechanical properties like cracks and failure modes are not commonly studied and investigated well. It is necessary to investigate the mechanical properties and characteristics for RC columns subjected to torsion during different types of loading including earthquakes. Also, as a reinforcing method to existing RC structures, the application of Carbon Fiber Reinforced Polymers (CFRP) became common. CFRP has properties of high tensile strength, light weight and easy execution. CFRP is easy to adjust the reinforcement volume whenever necessary and considered excellent in endurance because the rust will not occur. The purpose of this study is to present a model suitable for analyzing square RC columns strengthened with CFRP under torsional effects and developing a reasonable method for calculating angles of twist for square concrete columns using the finite element method. Final available version of finite element analysis software [ANSYS 14 – 64 bits] is used to solve the problem and to predict the torsional behavior 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 CFRP under torsion are studied in parametric study. These parameters include: the presence (distribution type) of CFRP, CFRP number of layers (thickness), type of interface between CFRP layers and concrete surface, CFRP orientation and effect of applying axial load in addition to torque. The results showed that zebra shape (where sheets are straight and fibers are inclined with 45o) is the best way to increase the torsional capacity of RC columns.
Ahmed Sameer Younus,
Ammar A. Abdul Rahman,
Evaluation of Torsional Capacity of Square RC Columns Strengthened with CFRP Using Finite Element Modeling, American Journal of Civil Engineering.
Vol. 1, No. 3,
2013, pp. 111-123.
Shrive P.L., Azarnejad A., Tadros G., McWhinnie C., and Shrive N.G., "Strengthening of concrete columns with carbon fiber reinforced polymer wrap ", Canadian Journal of Civil Engineering, May, Vol. 30, 2003, pp. 543–554.
Norayanan R., "Axially Compressed Structures Stability and Strength", Applied Science Publishers, LTD., 1982.
Zhou J., Hirosawa M., Kondo T., and Shimizu Y., "Effect of the torsional moment on the shear strength of reinforced concrete columns due to eccentric jointing of beam to column ", 12th world conference of earthquake engineering, Auckland, New Zealand, Sunday, 2000.
Manopulo N., "An Introduction to Finite Element Methods" Seminar: Interplay of Mathematical Modeling and Numerical Simulation, May, 2005, 16pp.
He, H.M., and Kiyomiya, O., "Study on torsion properties of carbon fiber sheets strengthened PC member with zebra-shaped", Journal of Structural Eng./ Earthquake Eng., JSCE, Vol. 25, No 1, 2008, pp. 1s-15s.
ANSYS, "ANSYS Help", Release 14.0, Copyright 2013.
ACI Committee 318, "Building Code Requirements fo Structural Concrete (ACI 318M-11) and Commentary (ACI 318R-11)", American Concrete Institute, Farmington Hills, MI, 2008, 466 pp.
Kachlakev D., Miller Th., Yim S., Chansawat K. and Potisuk T., "Finite Element Modeling of Reinforced Concrete Structures Strengthened with FRP Laminates", Report for Oregon Department Of Transportation, May, 2001, 99 pp.
Nilson A., Darwin D., Dolan C., "Design of Prestressed Concrete", John Wiley & sons, 2nd edition, 1987, 43 pp.