Research On The Reinforced Approach Pavement Temperature Deformation Performance And Key Points Ansysis Of Construction In Jointless Bridge

The expansion joints are canceled in the Jointless Bridges, while the thermal deformation produced in the superstructure can be absorbed by the reinforced approach pavement located behind the abutment, which consists of the base, the continuous reinforced layer and the asphalt concrete cover. Once the ambient temperature decreases, the reinforced approach pavement will have to bear an unfavorable tensile stress, in this case, the contraction generated in the main girder finally turns into some random slight cracks in the continuous reinforced layer. While in the opposite condition, the extension produced in the main girder ultimately results in the elastic compression of the continuous reinforced layer. In this dissertation, the following items are presented:(1) Recent accomplishments in the research of Jointless Bridges at home and abroad are introduced. Based on the reinforced approach pavement proposed by Bridge engineering institute of Hunan University, an improvement is presented, which introduces pre-compaction seams into the continuous reinforced layer.(2) An analytical model is developed, which perfectly describes the mechanical performance of the reinforced approach pavement suffered from ambient temperature drop. And formulas are derived to figure out the width of the cracks generated within the reinforced approach pavement implanted with pre-compaction seams. Furthermore, a program is developed to determine the required steel bars for the reinforced approach pavement to bear the thermal loads.(3) A scale model test is conducted, in which the mechanical behavior of the reinforced approach pavement suffered from ambient temperature drop is simulated by axial extension of the model. The experimental results manifests that most of the induced cracks emerges right by the pre-compaction seams, which means that the randomness of them are enormously eliminated. At the same time, the measured values of the width of the induced cracks perfectly agree with the values given by the proposed formulas, it means that the formulas recommended by the author are valid and applicable.(4) As the jointless bridge is a complicated system, in which the main girder, the approach slab, and the reinforced approach pavement interact with each other, it sets higher requirements for the construction procedure. Some key points of the construction technology, which deserves the attention of engineers, are summarized in this dissertation.