IntroductionA type of bridge that is used extensively in road applications in particular is the integral abutment bridge (IAB). The concept of "integral abutment bridge" has recently become a topic of remarkable 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. Integral bridges in simple words can be defined as bridges without joints. Integral bridges are characterized by monolithic connection between the deck and the substructure (piers and abutments). They span from one abutment, over intermediate support to the other abutment, without any joint in the deck.
Soil structure interaction for integral bridge.
Passive pressure that develops behind the integral bridge abutment depends on the soil density, soil to wall friction angle, mode of wall displacement, effect of backfill confinement and repeated loading. Handling the soil structure interaction in the analysis and design of integral abutment bridges has always been problematic. Using commercially available software the nonlinear soil behavior can be handled using nonlinear springs at the abutment and piles. The nonlinear soil springs behind the abutment walls are the force deflection design curves recommended in National Cooperative Highways Research Program (NCHRP) (1991) design manual.
Advantages of integral bridges
- Elimination of expansion joints and bearings:
- Simplified substructure:
- Slender superstructure
- Drive comfort improvement
- Remove of problematic details
- Robust structure
- Resistance to pressure
- Simplified widening and replacement
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