Monitoring of Haavistonjoki Bridge Abutment Performance, Finland

The main objectives of this paper are the integral abutment bridge: earth pressures after cyclic abutment displacements and the behavior of abutments, piers and steel pipe piles. Also the approach embankment temperatures were monitored. The instrumentation of Haavistonjoki Bridge was completed in autumn 2003 and the data were collected by monitoring 191 gauges that were installed in the bridge structure during construction. The instrumentation was used to measure the abutment's horizontal displacement, abutment rotation, abutment pile strains, earth pressure behind abutments, pier strains, superstructure displacements, frost depth, air temperature as well as thermal gradients in the superstructure next to abutment piles and in the approach embankment. Haavistonjoki Bridge is a 56 m long continuous 3-span slab bridge. The bridge is unskewed and totally jointless and the instrumentation showed that the vertical strains inside large steel pipe piles below an integral abutment follow the horizontal abutment displacements. The measured earth pressures on the bridge abutments were quite high because the backfill was well compacted and the values calculated with a soil modulus of elasticity Ed = 250,000 kPa corresponded best to the measured values.