EVALUATION OF DEFORMATION LIMITS IN CODES FOR REINFORCED CONCRETE COLUMNS

Predicting the deformation capacities of reinforced concrete columns is necessary for seismic evaluation of existing and new buildings. These deformation capacities have been set in terms of the rotation angle in EC-8 (2005) and ASCE/SEI 41 (2013) and strain in Turkish Seismic Code (2007-2016). In this study, finite element models of sixty-nine experimentally tested column specimens were modeled and analyzed by using nonlinear finite element method. As a result of the analyzes, data, which is difficult to measure in experiments such as the strain of outer fiber of confined concrete, were calculated and compared with code deformation limits. As a result of this study, EC-8 column ultimate deformation limits found to remain unsafe according to calculated deformation capacities herein. Taking into account TSC and ASCE/SEI 41, calculated capacities are in the safe region. However, for the axial load ratios over 0.45 and columns produced of high strength concrete, code limit state expressions are unable to predict the limit values correctly. In addition, TSC may significantly limit the deformation capacity of RC columns under their actual capacities. There is a need to improve these code limits using a more extensive column database which includes different design parameters.

Anahtar Kelimeler:

Deformation limits, RC Column, Finite element method

PDF

___

CEN (European Committee for Standardization). Design of structures for earthquake resistance. Part 3: Assessment and retrofitting of buildings. Eurocode 8, EN 1998-3. Brussels: Comite Europeen de Normalisation; 2005.
ASCE. Seismic rehabilitation of existing buildings. ASCE/SEI 41–13; 2013, Reston, VA.
Panagiotakos TB, Fardis MN. Deformations of RC members at yielding and ultimate. ACI Struct J 2001;98(2):135–48.
Haselton CB, Liel AB, Taylor LS, Deierlein GG. Beam-column element model calibrated for predicting flexural response leading to global collapse of RC frame buildings. PEER Rep. No. 2007/03. Berkeley: Pacific Engineering Research Center, Univ. of California; 2008.
TSC. Turkish seismic design code for buildings: Specification for structures to be built in disaster areas. Ministry of Public Works and Settlement, Ankara, Turkey, 2007.
TSC-Draft. Turkish seismic design code for buildings. Ankara, Turkey: Ministry of Public Works and Settlement; 2016.
Grammatikou S, Biskinis D, Fardis MN. Ultimate strain criteria for RC members in monotonic or cyclic flexure. J Struct Eng 2016;142(9). 04016046-1-13.
Özdemir M A, Kazaz İ, Ozkaya G S. Evaluation and comparison of ultimate deformation limits for RC columns. Engineering Structures 2017; 153: 569-581
Acun B, Sucuoğlu H. Performance of reinforced concrete columns designed for flexure under severe displacement cycles. ACI Struct J 2010; 107(3):364–71.
Bae S, Bayrak O. Drift capacity of reinforced concrete columns. ACI Struct J 2009;106(4):405-15.
Kazaz İ. Analytical study on plastic hinge length of structural walls. J Struct Eng 2013; 139(11):1938–50.
Kazaz İ, Gülkan P, Yakut A. Deformation limits for structural walls with confined boundaries. Earthq Spectra 2012; 28(3):1019–46.
Kazaz İ, Gülkan P, Yakut A. Performance limits for structural walls: an analytical perspective. Eng Str 2012; 43:105–19.
Berry M, Parrish M, Eberhard M. PEER Structural performance database user’s manual. Berkeley, CA: Pacific Engineering Research Center, Univ. of California; 2004.
ANSYS 14.5 [Computer software]. Canonsburg, PA, Ansys.
Eligehausen R, Popov EP, Bertero VV. Local bond stress-slip relationships of deformed bars under generalized excitations. Rep. No. UCB/EERC 83–23. Berkeley, CA: Earthquake Engineering Research Center, Univ. of California; 1983.
Montejo LA. Set of codes for the analysis of reinforced concrete members Ph.D. dissertation Raleigh, NC: Dept. of Civil, Construction and Environmental Engineering, North Carolina State Univ.; 2007.
Bayrak O, Sheikh, S. Confinement steel requirements for high strength concrete columns. In: Proc., 11th World Conf. on earthquake engineering, Acapulco, Mexico, Paper No. 463; 1996.
Saatcioglu M, Grira M. Confinement of reinforced concrete columns with welded reinforcement grids. ACI Struct J 1999;96(1):29–39.
Xiao Y, Yun HW. Experimental studies on full-scale high-strength concrete columns. ACI Structural Journal 2002;99(2):199–207.
Bayrak O, Sheikh S. Design of rectangular HSC columns for ductility. Special Publication ACI Structural Journal 2003;213:61–82.