Experimental Investigation of Shear Capacity of Precast Reinforced Concrete Box Culverts

This study presents an experimental program to investigate the shear capacity of precast reinforced concrete box culverts. Each culvert was subjected to monotonically increasing load through a $254\mathrm{mm}\times 508\mathrm{mm}$ $(10\mathrm{in.}\times 20\mathrm{in.})$ load plate in order to simulate the HS20 truckload per AASHTO 2005. Instrumentation included strain gauges, high-resolution laser deflection sensor, and automated data acquisition. Four tests were conducted on $1.22\mathrm{m}\times 1.22\mathrm{m}\times 1.22\mathrm{m}$ $(4\mathrm{ft}\times 4\mathrm{ft}\times 4\mathrm{ft})$ box culverts. The location of the load plate was varied to identify the position, which introduces the maximum shear stresses. Laser sensor data and dial gauge readings were recorded to measure the deflection profile of the box culvert. Strain gauges were placed on the steel reinforcement to measure axial strain at locations of maximum positive and negative bending moments. The test results include reporting the loads at which each crack initiated and propagated. The displacement profile of the top slab from the laser instrumentation output along with the load versus maximum deflection for each culvert is also reported.