Evaluation of the critical plastic region length in slender reinforced concrete bridge columns

Abstract This paper presents how the length of the critical plastic region (Lpr) in slender columns is significantly larger than what is estimated from current models, which were developed for shorter columns. Experimental results from three large-scale slender reinforced concrete columns with aspect ratios (length to depth) up to 12 were used to explore the effect of slenderness on Lpr. Components of Lpr, including linear moment gradient, nonlinear moment gradient, and tension shift effect were extracted from the test data and the contribution from each component was determined. Experimental Lpr values were compared with American, European, and New Zealand design guidelines. All design codes considered in this study significantly underestimated Lpr except for seismic design provisions provided by Caltrans. Previous expressions for the length of the plastic region were reexamined in light of the new experimental data and strong disagreement between experimental and predicted Lpr was observed. A new expression for Lpr, which correlates well with test data is thus proposed. The expression varies according to the magnitude of inelastic demands, defined by displacement ductility, and includes the effect of nonlinear moment gradient due to P-δ effects.

[1]  T. Paulay,et al.  Seismic Design of Reinforced Concrete and Masonry Buildings , 1992 .

[2]  Eric M. Hines,et al.  PLASTIC HINGE LENGTH OF REINFORCED CONCRETE BRIDGE COLUMNS , 2002 .

[3]  Enrico Spacone,et al.  FIBRE BEAM–COLUMN MODEL FOR NON‐LINEAR ANALYSIS OF R/C FRAMES: PART I. FORMULATION , 1996 .

[4]  Patrick Paultre,et al.  Seismic Performance of Circular High-Strength Concrete Columns , 2009 .

[5]  Eric M. Hines,et al.  Force-Displacement Characterization of Well-Confined Bridge Piers , 2004 .

[6]  Jack P. Moehle,et al.  Experimental Evaluation of the Seismic Performance of Reinforced Concrete Bridge Columns , 2004 .

[7]  Dawn E. Lehman,et al.  Lumped-Plasticity Models for Performance Simulation of Bridge Columns , 2008 .

[8]  Oguzhan Bayrak,et al.  Seismic performance of full-scale reinforced concrete columns , 2008 .

[9]  A. L. L. Baker,et al.  Inelastic Hyperstatic Frames Analysis , 1965 .

[10]  Pedro F. Silva,et al.  P-δ Effects on the Plastic Region of RC Bridge Columns: Closed-Form Solution , 2016 .

[11]  P. Mendis,et al.  Plastic Hinge Lengths of Normal and High-Strength Concrete in Flexure , 2002 .

[12]  Oguzhan Bayrak,et al.  Plastic Hinge Length of Reinforced Concrete Columns , 2008 .

[13]  Filip C. Filippou,et al.  Efficient Beam-Column Element with Variable Inelastic End Zones , 2009 .

[14]  J. Mander,et al.  Theoretical stress strain model for confined concrete , 1988 .

[15]  Robert Tremblay,et al.  Cyclic Testing of Large-Scale Rectangular Bridge Columns under Bidirectional Earthquake Components , 2011 .

[16]  Theodore V. Galambos,et al.  Structural stability of steel : concepts and applications for structural engineers , 2008 .

[17]  A. Leung,et al.  Analyses of plastic hinge regions in reinforced concrete beams under monotonic loading , 2012 .

[18]  Mervyn J. Kowalsky,et al.  Displacement-based seismic design of structures , 2007 .

[19]  Mjn Priestley,et al.  STRENGTH AND DUCTILITY OF CONCRETE BRIDGE COLUMNS UNDER SEISMIC LOADING , 1987 .

[20]  John B. Mander,et al.  SEISMIC DESIGN OF BRIDGE PIERS , 1984 .

[21]  D. Mitchell,et al.  Prestressed concrete structures , 1991 .

[23]  H. Ronagh,et al.  Plastic hinge length of FRP strengthened reinforced concrete columns subjected to both far-fault and near-fault ground motions , 2012 .

[24]  Jcm Ho,et al.  Length of critical region for confinement steel in limited ductility high-strength reinforced concrete columns , 2009 .

[25]  Manuel L. Romero,et al.  Experimental tests of slender reinforced concrete columns under combined axial load and lateral force , 2011 .

[26]  Y H Chai.  STEEL JACKETING OF CIRCULAR REINFORCED CONCRETE BRIDGE COLUMNS FOR ENHANCED FLEXURAL PERFORMANCE , 1991 .

[27]  A. Leung,et al.  Plastic Hinge Length in Reinforced Concrete Flexural Members , 2011 .

[28]  Mjn Priestley,et al.  Seismic Design and Retrofit of Bridges , 1996 .