Soil-structure interaction of rigid cast-in-place box culverts under high embankments

This research evaluates the soil-structure interaction associated with cast-in-place rigid box culverts by measuring earth pressures. The study is comprised of field instrumentation and monitoring supplemented with laboratory centrifuge testing.;A cast-in-place reinforced double cell rectangular box culvert installed under an induced trench constructed embankment was instrumented and monitored for earth pressures on the roof, sides and base. The average earth pressures measured on the roof and mid-height of the sidewalls were 0.42 and 0.52 times the overburden pressures respectively. The average measured base contact pressure was 0.58 times the overburden pressure plus the dead load pressure of the culvert. An average increase of 25% from the measured vertical earth pressures on the roof plus the pressure from the culvert dead load was recorded at the culvert base.;Two similar geometry cast-in-place rectangular prototype box culverts installed under similar fill height were compared for earth pressures based on their installation methods. Earth pressures on the roof and sidewalls of an induced trench culvert were compared with that of a positive projecting culvert. The average earth pressures on the roof of the induced trench constructed culvert showed a 39% reduction from the pressures measured on the roof of the positive projecting culvert. The average lateral pressure measured on the walls showed a 49% increase for the induce trench installation from that of the positive projection installation. Centrifuge tests conducted for each method of installation agreed closely with field measured pressures indicating that centrifuge testing can be used for preliminary evaluation of the designs.