Conventional bridge designs incorporate expansion joints at the ends of the bridge to accommodate the length changes due to environmental loading. However, expansion joints require frequent maintenance to ensure that their operation is not hindered by the collection of debris. To improve the ride quality and to reduce maintenance costs, bridge decks can be seamlessly connected to a continuous reinforced concrete pavement (CRCP). The changes in length of the seamless system, due to environmental loading, are accommodated through the formation of cracks in the concrete pavement, which expands and contracts as required. This pavement adjacent to the bridge, referred to as the transition pavement, mobilizes frictional forces at its interface with the base material upon contraction/expansion movements. As a result, this region of the pavement is subjected to significant tensile stresses during contraction and needs to be designed with sufficient longitudinal reinforcement to maintain an acceptable range of crack widths and spacing. In addition, an approach slab of varying thickness serves as the key element transmitting the longitudinal demands between the bridge and the transition pavement, while adjusting to any settlements to maintain continuity.
The goal of this research was to develop an analytical framework for predicting the response of seamless bridges, which can be used to inform seamless bridge designs. Seamless bridge and pavement systems were studied for in-plane (longitudinal) deformation effects using an analytical model developed using a commercial structural analysis software. The model was used to investigate the seamless bridge design used for the Westlink Motorway 7 in Australia. A parametric study was also conducted varying four key design parameters (coefficient of friction of transition pavement with base, length of transition pavement, thickness of approach slab and transition pavement, longitudinal reinforcement in transition pavement) to study their influence on the performance of the seamless system. Based on the Australian bridge design and the insights from the parametric analyses, the design of five concrete bridges representing typical Texas structures was modified to accommodate seamless connections. The in-plane performance of the five Texas bridges was studied analytically, and the amount of longitudinal steel required in the poor-boy joints (reinforcement ratio of 1.73%) and transition slabs (reinforcement ratio of 1.45% - 0.87%) was verified based on the analytical results. The approach slab of a Texas bridge was also analyzed under out-of plane (vertical) effects caused by settlement and traffic loads. Finally, recommendations for designing seamless bridge and pavement systems are provided based on the findings of this study.Civil, Architectural, and Environmental Engineerin
