Use of Mixed-Mode Fracture Interfaces for the Modeling of Large-Scale FRP-Strengthened Beams

In this study, numerical models of fiber-reinforced polymer (FRP)-strengthened beams were developed using nonlinear fracture mechanics for the modeling of the concrete-FRP (longitudinal and U-wrap) interfaces. Mode 1, Mode 2, and mixed-mode interfacial behaviors were considered. Results from the finite-element models were compared with experimental tests of large-scale strengthened beams using FRP U-wraps as anchors. The numerical program assessed the effect of the interfacial modeling in the global and local responses. A parametric study was conducted to determine the effect of additional longitudinal FRP sheets in strengthened beams with and without FRP U-wraps. Results from this study indicate that the use of a mixed-mode concrete-FRP interface is a robust numerical approach for the prediction of the global and local responses of large-scale FRP-strengthened beams. The parametric study shows that the use of FRP U-wraps could improve the strength and ductility of the FRP-strengthened beams by changing their failure mode and deflection response. Appropriate modeling of the concrete-FRP interfaces is needed to successfully predict these effects.

[1]  Stephanie L. Walkup,et al.  Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-02) , 2005 .

[2]  Maria M. Lopez,et al.  Numerical Modeling of Concrete-FRP Debonding Using a Crack Band Approach , 2010 .

[3]  O. Buyukozturk,et al.  FAILURE BEHAVIOR OF PRECRACKED CONCRETE BEAMS RETROFITTED WITH FRP , 1998 .

[4]  J. Davalos,et al.  Appraisal of the novel single contoured-cantilever beam , 2005 .

[5]  U. Ebead,et al.  Flexural and Interfacial Behavior of FRP-Strengthened Reinforced Concrete Beams , 2007 .

[6]  Z. Hashin,et al.  A Fatigue Failure Criterion for Fiber Reinforced Materials , 1973 .

[7]  Maria M. Lopez,et al.  Damage Approach for the Prediction of Debonding Failure on Concrete Elements Strengthened with FRP , 2007 .

[8]  Michael R Wisnom,et al.  A concise interface constitutive law for analysis of delamination and splitting in composite materials and its application to scaled notched tensile specimens , 2007 .

[9]  Solomon C. Yim,et al.  REMAINING LIFE OF REINFORCED CONCRETE BEAMS WITH DIAGONAL-TENSION CRACKS , 2004 .

[10]  E. Oñate,et al.  A plastic-damage model for concrete , 1989 .

[11]  Maria M. Lopez,et al.  Experimental Characterization of Concrete-Epoxy Interfaces , 2008 .

[12]  Claudio Modena,et al.  FRP strengthening of steel and steel-concrete composite structures: an analytical approach , 2009 .

[13]  Carlos Arturo Coronado.  CHARACTERIZATION, MODELING AND SIZE EFFECT OF CONCRETE-EPOXY INTERFACES , 2006 .

[14]  Wisnom,et al.  Effect of Through Thickness Tensile and Compressive Stresses on Delamination Propagation Fracture Energy , 1994 .

[15]  Pizhong Qiao,et al.  EVALUATION OF FRACTURE ENERGY OF COMPOSITE-CONCRETE BONDED INTERFACES USING THREE-POINT BEND TESTS , 2004 .

[16]  Michael E. Kreger,et al.  INCREASING FLEXURAL CAPACITY OF REINFORCED CONCRETE BEAMS USING CARBON FIBER-REINFORCED POLYMER COMPOSITES , 2003 .

[17]  Maria M. Lopez,et al.  Slip effects in reinforced concrete beams with mechanically fastened FRP strip , 2009 .

[18]  Zhishen Wu,et al.  Full-range behavior of FRP-to-concrete bonded joints , 2004 .

[19]  Jin-Guang Teng,et al.  Bond-slip models for FRP sheets/plates bonded to concrete , 2005 .

[20]  Jialai Wang.  Cohesive-bridging zone model of FRP–concrete interface debonding , 2007 .

[21]  O. Büyüköztürk,et al.  Debonding of FRP plated concrete: A tri-layer fracture treatment , 2006 .

[22]  Costas P. Antonopoulos,et al.  Design of Concrete Flexural Members Strengthened in Shear with FRP , 2000 .