Journal of Bridge Engineering

Using recycled coarse aggregate (RCA) in construction reduces the negative environmental impacts that are associated with new concrete production. However, few studies have investigated the structural performance of bridge piers made of recycled aggregate concrete (RAC), which utilizes RCA as coarse aggregate. This paper experimentally investigated the seismic performance of RAC bridge piers. Here, three 1/3-scaled bridge piers having three levels of RCA replacement ratios (0%, 50%, and 100%) were tested. The piers represented a real bridge pier located in Vancouver, British Columbia, Canada. Their seismic performances were evaluated using a quasi-static cyclic loading protocol in the form of hysteresis behavior, strain response, moment–curvature response, energy dissipation, residual deformation, ductility measures, plastic hinge length, and failure modes. The results showed that the RAC piers had similar hysteresis and strain response behavior when compared to the conventional concrete specimen. The ductility measures for the three specimens were very close in terms of curvature and displacement ductility. Moreover, RAC specimens had slightly larger plastic hinge length, experiencing more cracks compared to the control specimen. These findings highlighted the feasibility of using RCA as a replacement of coarse aggregate in bridge piers in seismic regions.

Full-depth precast concrete deck systems have several advantages compared with cast-in-place concrete deck systems in bridge construction, such as improved construction quality and safety, reduced construction duration and traffic disruption, and less dependence on weather and site conditions. Existing full-depth precast concrete deck systems use either shear pockets or open troughs to connect deck panels to supporting girders via shear connectors to achieve composite sections. These connections often complicate panel and girder fabrication and erection due to their tight tolerances, which reduces the attractiveness of precast systems. This paper presents the design and testing of a circular shear pocket connection with a single shear connector for simplified production and accelerated construction. The shear pocket will be formed using a stay-in-place large-diameter round steel hollow structural section (HSS) to provide adequate tolerance around the shear connector. A single large-diameter high strength threaded rod will be used as a shear connector at 1.2 m (4 ft) spacing in the longitudinal direction. A 100 mm (4 in.) diameter grouting hole at the center of each covered shear pocket will be used to allow filling of the shear pockets and haunch area while minimizing deck surface penetrations. Experimental investigation (push-off testing) and nonlinear finite element analysis (FEA) will be performed to validate the performance of the developed connection when different round HSS diameters and thicknesses were used. Analysis and testing results indicated that the capacity of the new connection could be predicted using the current AASHTO LRFD interface shear provisions. The implementation of the proposed connection to the construction of the Belden–Laurel Bridge, Nebraska is presented.

A butterfly web girder is a box girder that has discretely distributed side-surface openings. Due to these openings, butterfly web girders show better aerodynamic performance than conventional box girders. This study aims to investigate the effects of side-surface openings on the aerodynamic instability of a box girder when it is placed in tandem with another girder. In addition, this study aims to investigate whether the aerodynamic instability of one girder is affected by the side-surface openings of an adjacent girder. A series of wind tunnel tests will be carried out on a butterfly web girder and conventional box girder, with another rigidly supported butterfly web girder or conventional box girder, respectively, at its upstream or downstream side. The fixed downstream girder increased the galloping instability of the upstream girder, and the fixed upstream girder amplified the vortex-induced vibration of the downstream girder. The side-surface openings of the upstream girder stabilized its galloping and vortex-induced vibration, irrespective of the type of girder downstream. The side-surface openings of the downstream girder stabilized its vortex-induced vibration independent of the type of girder upstream.

A dual resonator with electromagnetic transduction was developed to harvest bridge vibration energy at low acceleration and low frequency. The harvester had two cantilever beams: one to carry magnets and the other to carry the coil. The coil was held by the coil holder on the coil-beam in a vertical direction to have a poling direction of magnets perpendicular to it. The device was characterized in-lab and in real bridge environment. In in-lab experimentation at acceleration. In the lab, at acceleration of 0.07 g, the harvester produced 2.7 V voltage and 13 mW power (555 Ω optimal load resistance) output at the first resonant frequency of 3.2 Hz, and output voltage of 3.1 V and 7.8 mW power (at optimal load resistance of 1,200 Ω) at the second resonant frequency of 4.2 Hz. Furthermore, when the voltage was rectified from AC to DC and at 100 kΩ optimal load resistance, 0.5 g acceleration, the output voltage of 19.4 V and power of 3.764 mW was available at 3.2 Hz frequency. A battery was also charged with the DC output of the harvester. Moreover, the real bridge environment characterization tests were made on two prestressed I-section concrete bridges. The harvester on one bridge location produced a peak load voltage of 0.27 V and a peak power of 0.13 mW at resistive load of 555 Ω and 0.024 g peak bridge acceleration. At the second bridge, where the peak acceleration was 0.017 g, the harvester successfully generated a load voltage of 0.32 V and power of 0.18 mW.

The large-amplitude postflutter vibrations of long-span bridges have attracted extensive attention, which is of significant importance to accurately assess the potential wind-resistant capability of bridges. However, the conventional free vibration testing apparatus cannot effectively fulfill the task of evaluating the postflutter performance of a bridge deck. This study introduces a new experimental device that can effectively avoid various nonlinear factors involved in the traditional device and thereby ensure the accuracy of large-amplitude vertical­–torsional coupled free vibration tests. The excellent working performance of the experimental setup is validated by carrying out free vibration tests of a bridge deck sectional model in still air. Large-amplitude wind tunnel tests of two bridge decks are conducted by using the new setup, and it is found that the novel testing device is a preferable choice for wind tunnel tests to comprehensively evaluate the postflutter performance of bridge decks.