The dynamic amplification factor (DAF) is an important parameter in the design of highway bridges and yet no worldwide consensus has been reached so far as to its value. Some disagreement exists between provisions of various national bridge codes. This is because the DAF depends, in addition to the maximum span or the natural frequency, on many other parameters that are difficult to take into account with reasonable accuracy. Vehicle speed, weight, and dynamic characteristics, the state of the structure, roadway roughness, expansion joints, the type of bridge supports, soil–structure interaction, and influence of secondary elements are some aspects influencing the DAF. This study reviews the analytical and experimental findings on bridge dynamics and the evaluation of the DAF. Key words: bridges, vibrations, bridge testing, bridge design codes, dynamic amplification factor.

Embedded through-section (ETS) technique is a recently developed method to increase the shear capacity of reinforced concrete (RC) using fiber-reinforced polymer (FRP) rods. The ETS method presents many advantages over existing methods, such as externally bonded FRP sheets (EB FRP) and near-surface mounted FRP rods (NSM FRP). Unlike EB and NSM methods where the FRP relies on the concrete cover of RC beams, in the ETS method, the FRP relies on the concrete core of the RC beam, which offers a greater confinement and hence improves bonding performance. Additionally, the ETS method requires less concrete preparation compared with EB and NSM methods. The objective of this paper is to present results of an experimental investigation that studies the effectiveness of the ETS method and compares the performance of the ETS method with both EB and NSM methods. In total, 12 tests are performed on 4,520-mm-long T-beams. The parameters investigated are as follows: (1) the effectiveness of the ETS method, compared with...

This paper presents results of a comprehensive experimental investigation on the behavior of axially loaded short rectangular columns that have been strengthened with carbon fiber-reinforced polymer (CFRP) wrap. Six series, a total of 90 specimens, of uniaxial compression tests were conducted on rectangular and square short columns. The behavior of the specimens in the axial and transverse directions is investigated. The parameters considered in this study are (1) the concrete strength; (2) the aspect ratio of the cross section; and (3) the number of CFRP layers. The findings of this research can be summarized as follows: The CFRP wrapping enhances the compressive strength and the ductility of both square and rectangular columns, but to a lesser degree than that of circular columns. The ultimate strength and the ductility of the CFRP confined concrete increase with increasing number of confining layers. The increase in strength and ductility is more significant for lower strength concrete, representing po...

In recent years, numerous investigations have addressed the shear strengthening of reinforced concrete (RC) beams with externally bonded fiber-reinforced polymer (FRP) composites. Despite this research effort, the mechanisms of shear resistance that are developed in such a strengthening system have not yet been fully documented and explained. This clearly inhibits the development of rational and reliable code specifications. This paper aims to contribute to the understanding of the shear resistance mechanisms involved in RC beams strengthened in shear with externally bonded FRP. It is based on results obtained from an experimental program, involving 17 tests, performed on full size T beams, and using a comprehensive and carefully optimized measuring device. The resistance mechanisms are studied by observing the evolution of the behavior of the strengthened beams as the applied loads are increased. The local behavior of the FRP and the transverse steel, in particular in the failure zones, are thoroughly ex...

This paper deals with the shear strengthening of RC beams using externally bonded (EB) fiber-reinforced polymers (FRP). Current code provisions and design guidelines related to shear strengthening of RC beams with FRP are discussed in this paper. The findings of research studies, including recent work, have been collected and analyzed. The parameters that have the greatest influence on the shear behavior of RC members strengthened with EB FRP and the role of these parameters in current design codes are reviewed. This study reveals that the effect of transverse steel on the shear contribution of FRP is important and yet is not considered by any existing codes or guidelines. Therefore, a new design method is proposed to consider the effect of transverse steel in addition to other influencing factors on the shear contribution of FRP ( Vf ) . Separate design equations are proposed for U-wrap and side-bonded FRP configurations. The accuracy of the proposed equations has been verified by predicting the shear st...