Abstract

The concept of "integral abutment bridge" has recently become a topic of remarka-ble interest among bridge engineers, not only for newly built bridges but also during refurbishment processes. The system constituted by the substructure and the superstructure can achieve a composite action responding as a single structural unit; the elimination of expansion joint and bearings on the abutments, greatly reduce the construction and maintenance costs. To maximize the benefits from integral abutment bridges, the direct way is to achieve the super-long integral abutment bridge. However, as the environment temperature changes, the lengths of superstructure increase and decrease, pushing the abutment against the approach fill and pulling it away. The responses of bridge superstructure, the abutment, the approach system, the foundation/piles and the foundation soil are all different. And it's important to understand their interactions effective design and satisfactory performance of integral abutment bridges. In order to build longer integral abutment bridges, therefore in this research, the lit-erature survey on the applications of integral abutment bridges in worldwide, espe-cially the current development of super-long integral abutment bridges was carried out firstly. Another literature review on soil-structure interaction was conducted to find out the most suitable methods in considering this kernel issue in design of integral abutment bridge. Through proposing finite element models for integral abutment bridges that could involve the soil-structure interaction, thermal actions, non-linearity in materials and so on, structural study was performed on an existing super-long integral abutment bridge, including parametric analysis, pushover analysis, and dynamic tests. Then, the performance of integral abutment bridge was better understood, and no critical structural problem was found for integral abutment bridge. Based on that, length limit for this kind of bridge was evaluated and investigated in an analytical way. Considering capacities of abutments and piers, and under the conditions of an existing integral abutment bridge, the length limit was found to be around 540m. With this super length, the piles need to be designed with capacity of large lateral displacement. Therefore, an effective optimization approach, associating the finite element method with global optimization algorithm was presented for pile shape design. At the end, considerations accounted in the design of super-long integral abutment bridges were discussed, making construction of super-long integral abutment bridge of great possibility.