Full-depth Precast Deck Panels Research Articles

Pretest analysis of shake table response of a two-span steel girder bridge incorporating accelerated bridge construction connections

This paper presents pretest analysis of a shake table test model of a 0.35-scale, two-span, steel plate girder bridge. The objective of pretest analysis was to obtain an insight on the seismic response of the bridge model during the shake table tests. The bridge included seat type abutments, full-depth precast deck panels, and a two-column bent in which columns were pinned to the footing and integral with superstructure. Six accelerated bridge construction connections were incorporated in the bridge model. An analytical model was developed in OpenSees and was subjected to ten input bi-directional earthquake motions including near-fault and far-field records. The overall seismic response of the bridge was satisfactory for all the earthquake records at 100%, 150%, and 200% design level. All connections and capacity-protected components remained elastic, and the average ductility capacity surpassed the ductility demand even at 200% design level. Using experimental fragility curves developed for RC bridge columns, it was predicted that there was a probability of 45% that columns would undergo the imminent failure in the last run and a probability of 30% for their failure.

Shear Transfer Mechanism and Design of Shear Connectors for Full-Depth Precast Deck Panel System

The development and implementation of full-depth, precast overhang panel systems has the potential to improve constructibility, productivity, and make bridges more economical. Recently, various shear connector systems have been proposed to provide shear-transfer resistance between girders and the precast overhang panels. There is, however, limited information and guidance on the design for shear-transfer capacities for full-depth, precast overhang panel systems. This research performed experiments and assessed the results to estimate the shear-transfer capacities of four types of shear connectors systems. The confinement system of the shear pocket was varied with the hopes of enhancing the sheartransfer capacity. Results indicate that five stages of shear-transfer and failure mechanisms occur during testing. These stages include initial adhesion loss, shear key action, shear key action failure, dowel action of the shear connectors at a sustained load, and final failure of the system. Results from this research indicate that steel reinforcing hoops placed in the shear pocket and shear reinforcing hoops placed in the overhang panel around the opening of the shear pocket provide limited or no improvement in capacity of the shear connector/coupler system. When comparing energy absorption capacities, however, the shear connector systems evaluated can provide improved performance when compared with the conventional R-bar system. A new equation is proposed based on this research.

Bridge Deck Load Testing Using Sensors and Optical Survey Equipment

Bridges are under various loads and environmental impacts that cause them to lose their structural integrity. A significant number of bridges in US are either structurally deficient or functionally obsolete, requiring immediate attention. Nondestructive load testing is an effective approach to measure the structural response of a bridge under various loading conditions and to determine its structural integrity. This paper presents a load-test study that evaluated the response of a prefabricated bridge with full-depth precast deck panels in Michigan. This load-test program integrates optical surveying systems, a sensor network embedded in bridge decks, and surface deflection analysis. Its major contribution lies in the exploration of an embedded sensor network that was installed initially for long-term bridge monitoring in bridge load testing. Among a number of lessons learned, it is concluded that embedded sensor network has a great potential of providing an efficient and accurate approach for obtaining real-time equivalent static stresses under varying loading scenarios.