A new type of integral bridge comprising geosynthetic-reinforced soil walls

摘要

ABSTRACT: Integral bridges, comprising a continuous bridge girder (i.e. deck) integrated to a pairnof abutments without using hinged and movable shoes (i.e. bearings), have been constructed tonalleviate several inherent drawbacks of conventional bridges. It is shown that this conventional typenof integral bridge still has the following problems: (1) large residual settlements in the backfill,ndeveloping a bump immediately behind the abutments, and the development of high residual earthnpressure on the back of the abutments by seasonal thermal expansion and contraction of the girder,nas well as by traffic loads on the backfill; and (2) large detrimental deformation of the backfill bynseismic loads. To alleviate these problems, it is proposed to reinforce the backfill with geosyntheticnreinforcement that is firmly connected to the full-height rigid facings (i.e. abutments). A newlynproposed integral bridge, called the GRS integral bridge, is constructed in stages: first,ngeosynthetic-reinforced backfill; second, pile foundations (if necessary); third, full-height rigidn(FHR) facings (i.e. abutments); and finally a continuous girder integrated to the top of the twonabutments, without using shoes. A series of static cyclic loading tests, laterally on the facing andnvertically on the crest of the backfill, and shaking-table tests were performed on models of thenconventional and new types of integral bridge, as well as two conventional bridge types comprisingnRC gravity-type abutments and geosynthetic-reinforced soil-retaining walls, both supporting a girdernvia shoes. The test results showed high static and dynamic performance of the GRS integralnbridge, despite its simple structure and construction procedure, and therefore its low constructionncost.