Approach slab pavement at integral abutment bridges are prone to settlement and cracking whichhas been long recognized by the Iowa DOT. A common solution to these problems is to attachthe approach slab to the bridge abutment. Studies were conducted to investigate the behavior ofapproach slabs by implementing health monitoring systems on approach slabs, interpreting thedata obtained during the 12-month monitoring, and conducting periodic visual inspections at twobridge sites (O'Brien and Bremer). Based on the information obtained from the testing thefollowing general conclusions were made: The connection between the approach slabs and thebridges appear to function well with no observed distress at these locations and no relativemovements measured between the two components; The measured strains in the approach slabsindicate a notable force exists at the expansion joints between the approach slab and thepavement and should be taken into consideration when designing both the approach slab and thebridge; Although measures were taken to reduce frictional forces on the slabs notable frictionwas measured – further, the Bremer site had higher frictional forces. The observed responsesgenerally followed an annual cyclic as well as short term daily cyclic pattern.
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