Research On The Performance Of Integral Abutment Jointless Bridge

Recently the jointless bridges have been rapidly developed and widely usedaround the world. The integral abutment bridge(IAB), a typical jointless bridge, waspredominantly applied in foreign countries, while in China, semi-integral abutmentjointless bridge(SIAJB) was mostly used. Based on the above two sorts of jointlessbridges which were widely used in China and Abroad, a new form of integralabutment bridge had been put forward in this paper, which was called "full integralabutment jointless bridge(FIAJB)". In FIAJB, IAB’s integral abutment and SIAJB’sapproach pavement were applied. Therefore, the FIAJB combines the advantages ofIAB and SIAB. The main work and conclusions in this paper are as follows:(1) The structural forms of the jointless bridges have been introduced and theapplication situation both in China and Abroad has also been presented in this paper.The key problems of jointless bridges constructed in China and Abroad werediscussed in detail.(2) The way of calculating soil-abutment and soil-pile interaction used in foreigncountries has been concretely introduced. Base on Qingyuan Sijiu bridge which wasan integral abutment bridge constructed in China, an ANSYS numerical model withthe way of calculating soil-structure interaction introduced in this study was built.The results of comparing calculation values with measured values have showed that:it was reasonable that the earth pressure coefficient behind the abutment changedlinearly when the integral abutment moved towards the backfill and the p-y curvemethod was adopted to model soil-pile interaction, and the calculation values wereclose to the measured values when the temperature changed obviously.(3) Based on the structure forms and sizes of the in-service IABs and SIAJBsconstructed in China, an integral abutment jointless bridge and an integral abutmentbridge were designed, and the numerical models of the FIAJB and IAB was built. Acomparison of the internal forces and deformations between the two kinds of bridgeshave indicated that the piles in FIAJB will experience lower displacements andstresses but the abutment will experienced higher tension stress.(4) According to the structure characteristics of FIAJB and IAB, a series ofnumerical models have been built to investigate the influence of critical parameters onthe deformations and internal forces of FIAJB and IAB. In the parametric study, the following factors have been considered:(a) abutment height;(b) backfill stiffness;(c)soil stiffness;(d) girder-abutment joint stiffness;(e) bridge length. Results of theparametrical study show that: abutment height, girder-abutment joint stiffness andbridge length have great influence on the above two sorts of jointless bridges.In this article, a comparison between FIAJB and IAB and a parametric study ofthem have been done to investigate the characteristics of deformations and internalforces, which will provide theoretical basis for further study on FIAJB and IAB andapplication of them.