Search

1 10

This research assesses the effects of the presence of water during the carbon fiber reinforced polymer (CFRP) application and after the CFRP cure on the bond between the CFRP and the concrete. Modified double cantilever beam (MDCB) specimens are used to determine the interfacial energy release rate, G, of the CFRP—concrete bond. A CFRP fabric is applied to the specimens with three different initial levels of water/moisture presence. Other specimens, with a CFRP fabric applied in dry conditions and allowed to cure, are conditioned in a saturated environment for different lengths of time. The test results indicate that the presence of water during the CFRP application decreases the bond quality significantly and most of the resulting failures are adhesive failures along the primer/concrete interface. The use of a specially formulated primer results in a slightly higher bond capacity but the same undesirable failure. High quality CFRP applications, conditioned in a saturated environment for a relatively short period of time, from 3 to 8 weeks, demonstrate that exposure to water degrades the bond between CFRP and concrete after the epoxy has cured.

This research studies the structural behavior of a GFRP bridge deck system. The study develops FEM models of the GFRP bridge deck system using ANSYS 7.0 software package. Data collected from field measurements and laboratory testing is used to validate and calibrate the proposed FEM models. Parametric studies through computer simulations are conducted to investigate the characteristics of the system. Four parameters are considered for service load conditions: (a) presence of diaphragms, (b) girder stiffness, (c) girder spacing, and (d) composite action. In addition, geometric and material nonlinearities are considered in the investigation of the capacity of the new bridge system. The analysis results are discussed and conclusions on the GFRP deck system are presented.

An experimental study of principal strains and deflections of glass fiber-reinforced polymer (GFRP) composite bridge deck systems is presented. The experimental results are shown to correlate well with those of an analytical model. While transverse strains and vertical deflections are observed to be consistent, repeatable, and predictable, longitudinal strains exhibit exceptional sensitivity to both strain sensor and applied load location. Large, reversing strain gradients are observed in the longitudinal direction of the bridge deck. GFRP deck system geometry, connectivity, material properties, and manufacturing imperfections coupled with the observed strains suggest that the performance of these structures should be assessed under fatigue loading conditions. Recommendations for accurately assessing longitudinal strain in GFRP bridge decks are made, and a review of existing data is suggested.

99 208 214

99 577 585

98

97 479 485