The U.S. military must often deploy to other countries where bridges may have insufficient strength for their heavy tactical vehicles. In recent years, fiber-reinforced polymeric (FRP) materials have emerged as a viable retrofit scheme for strengthening reinforced concrete bridges. However, because of stringent application requirements, long cure times, and climatic sensitivity, this technology has yet to prove feasible for military operations where time is often the most critical factor. Furthermore, Army operations are conducted under the broadest range of climatic conditions. For these reasons, the U.S. Army Engineer Research and Development Center has undertaken to develop a unique FRP application methodology utilizing powder-actuated mechanical fasteners (i.e., nails from a conventional carpenter's nail gun). This method shows great promise for military applications, since no substrate preparation or adhesive curing is required. Additionally, this method should work well in all but the most extreme environments. For this purpose, numerous laboratory tests have been conducted, and the results have been very promising. This report provides a detailed summary of the first 2 years of testing on this concept.

This book analyses the current knowledge on structural behaviour of RC elements and structures strengthened with composite materials (experimental, analytical and numerical approaches for EBR and NSM), particularly in relation to the above topics, and the comparison of the predictions of the current available codes/recommendations/guidelines with selected experimental results. The book shows possible critical issues (discrepancies, lacunae, relevant parameters, test procedures, etc.) related to current code predictions or to evaluate their reliability, in order to develop more uniform methods and basic rules for design and control of FRP strengthened RC structures. General problems/critical issues are clarified on the basis of the actual experiences, detect discrepancies in existing codes, lacunae in knowledge and, concerning these identified subjects, provide proposals for improvements. The book will help to contribute to promote and consolidate a more qualified and conscious approach towards rehabilitation and strengthening existing RC structures with composites and their possible monitoring.

The deterioration of steel in aging reinforced concrete bridges is a continual problem which could benefit from improved rehabilitation techniques that take advantage of enhanced and more durable materials such as fiber reinforced polymer (FRP) composites. Appropriately designed hybrid material systems benefit from the performance and durability advantages of FRP materials yet remain more cost effective than comparable all-composite systems. Development of rapid rehabilitation systems for the decks of concrete box girder bridges, which are increasingly common throughout the United States, is presented. One goal of this research is to assess and validate the use of FRP composite panels for use as both stay-in-place formwork and as the bottom longitudinal and transverse reinforcement in the deck of concrete box girder bridges. Performance assessments for full-scale two-cell box girder bridge specimens through monotonic and extensive cyclic loading provided validation for the FRP panel system bridge deck as a viable rehabilitation solution for box girder bridge decks. The FRP panel system performed comparably to a conventionally reinforced concrete bridge deck in terms of serviceability, deflection profiles, and system level structural interaction and performed superior to the RC bridge deck in terms of residual deflections, and structural response under cyclic loading. Assessment of a damaged FRP panel bridge deck system, which was repaired using a resin injection technique, showed superior performance for the repaired system in terms of integrity of the FRP panel interface and cyclic response. Rapid rehabilitation techniques for strengthening reinforced concrete box girder bridge deck overhangs using near-surface-mounted (NSM) carbon fiber reinforced polymer (CFRP) were also evaluated. Analytical predictions of load carrying capacity and deflections provided correlation with experimental results, and the developed analysis methods provide an effective design tool for future research. Results from the laboratory testing of a bridge deck overhang strengthened with FRP showed significant increases in load carrying capacity as well as deformation capacity as compared to the as-built specimen without FRP. This research provides enhanced understanding of hybrid structures and indicates significant potential for rehabilitation applications to concrete box girder bridges.