Effective fire protection measures for field deployment of FRP strengthened concrete beams.

摘要

Numerous investigations have been performed to evaluate the structural capacity and the suitability of using Fiber Reinforced Polymer (FRP) materials in stiffening or strengthening existing concrete and steel structures. Results of different research projects were organized and documented in several codes and design guidelines to facilitate the deployment of FRP materials in field applications. However, the performance of FRP materials under fire events has not been fully addressed by researchers. The lack of enough fire research imposed a significant limitation on the use of FRP materials in many structural applications, where fire event is a concern.;Through this study, an experimental program was developed to investigate the performance of rectangular reinforced concrete beams strengthened with FRP materials under fire/loading events. Thirteen rectangular beams were constructed and tested to failure. Three beams served as control beams and were tested under three-point-loading set-up at ambient temperature. Other beams were exposed to ASTM E119 fire scenario from four sides and tested under the same loading configuration. Beams tested under fire/loading events were provided with different kinds of supplemental fire insulation layers.;In addition, the results and observations collected from the experimental investigation were employed to conduct an extensive numerical investigation. First, the modeling technique was optimized and verified by simulating the behavior of selected beams from the experimental investigation. Numerical beam models were generated and analyzed under load at both ambient temperature and fire event. The response of the numerical beam models was compared to that of the experimental beam specimens. Second, after gaining confidence in the numerical simulation, the investigation extended to address the effect of different parameters on the fire resistance of FRP beam strengthening systems. Finally, the results of the numerical investigation were organized, analyzed, and presented in simple mathematical formulas that can be employed in fire design codes. The experimental/numerical investigation revealed that the common hypothesis that strength of FRP system should be neglected during fire is inaccurate and underestimates the capacity of the strengthened structural element during fire events.