Flexural Performance of Carbon Fiber-Reinforced Polymer ...

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(100 kip) force. The bridge was subjected to incremental staticcycles of 111, 156, 222, 334, and 378 kN (25, 35, 50, 75, and85 kip) to determine the cracking load and the elastic and inelasticdeformations. After the quasi-static load cycle test, the bridgemodel was loaded until failure.Numerical AnalysisFig. 5. Creating longitudinal deck cracks on the bridge model (photocourtesy of Center for Innovative Materials Research, LawrenceTechnological Univ.)The ultimate failure load observed from the experimental investigationwas compared with the numerically predicted loadin a 3-dimensional (3D) finite-element analysis (FEA) of the bridgemodel. The software package ABAQUS (2008) was used. The boxbeams of the bridge and the deck slab were modeled with 8-nodebrick elements (C3D8R). The pretensioned and nonpretensionedCFCC strands were modeled by using 2-node linear 3D truss elements(T3D2). The bridge model was meshed with a maximummesh size of 102 mm (4 in.) and shown in Fig. 6. The longitudinalpretensioned and the TPT forces were applied as concentratedforces at the ends of the pretensioned strands and at the bearingplates located by each transverse diaphragms, respectively.Fig. 6. Finite-element mesh of the bridge modelFig. 7. Deflection response of the bridge model with beam B4 loaded–varying TPT level666 / JOURNAL OF COMPOSITES FOR CONSTRUCTION © ASCE / SEPTEMBER/OCTOBER 2011Downloaded 18 Nov 2011 to 198.111.39.24. Redistribution subject to ASCE license or copyright. Visit http://www.ascelibrary.org
The elastic behavior of the concrete and the CFCC reinforcementswere defined by their modulus of elasticity andPoisson’s ratio. Concrete exhibits both elastic and inelastic behaviorduring loading; the inelastic behavior is complex becauseit involves modeling of the cracking behavior, compression hardening,and tension softening of the concrete. The “ConcreteDamaged Plasticity” model available in the software packagewas used.Results and DiscussionLoad DistributionTypical results of the load-distribution test are presented in Figs. 7and 8. The general results obtained from the test are discussedsubsequently.Effect of Varying TPT Force LevelThe effect of varying the TPT force level on the bridge model wasinsignificant when the bridge deck was uncracked. A constant deflectionof 5.33 mm (0.21 in.) was observed in each loaded beamand unloaded adjacent beams at all TPT force levels. For thecracked deck slab, a significant effect of the TPT force levelwas observed. When the force was increased from 0–178 kN(0–40 kip), a decrease in overall bridge deflection was observed.Yet, increasing the force beyond 178 kN (40 kip) up to 445 kN(100 kip) did not result in any significant change in the deflectionresponse.The full-depth shear keys and the deck slab were effective indistributing the single point load equally to all the beams whenthe bridge experiences no longitudinal deck cracks. However, oncecracking occurs, increasing the TPT force level improved the distributionof the applied load to all the beams and increased theflexural stiffness of the bridge model.Fig. 8. Deflection response of bridge model with beam B4 loaded–number of diaphragmsFig. 9. Strain distribution on the box beam bridge model at 100 and 40 kipJOURNAL OF COMPOSITES FOR CONSTRUCTION © ASCE / SEPTEMBER/OCTOBER 2011 / 667Downloaded 18 Nov 2011 to 198.111.39.24. Redistribution subject to ASCE license or copyright. Visit http://www.ascelibrary.org
Page 2 and 3: This paper presents the experimenta
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