Investigation of Potholes in Concrete Slab Bridges

Abstract

This paper presents experimental and finite element results to accurately evaluate the effect of potholes on the load distribution and performance of concrete slab bridges. This paper will assess the effect of deterioration in simply-supported, one-span, concrete slab bridges subject to AASHTO HS20 loading. The typical two-lane bridge selected for this study had 40 ft (12.2 m) span length, 34 ft (10.4 m) width, and 2 ft (0.6 m) slab thickness. The finite element method was used to model the concrete slab using rectangular SHELL elements. Three one-fifteenth size scale models of the reinforced concrete slab bridges were constructed and tested in the laboratory. Electric resistance strain gages were mounted on the concrete slabs to monitor strains associated with various positions of HS20 wheel loads. The back two axles of the AASHTO HS20 design truck were positioned in each lane and load superposition was used to find the strain values at mid-span. Results of the reference slab subject to multiple lane loading indicated that the slabs behaved as wide beams with minor variation in longitudinal bending moments across the widths of the slabs. The test results compared well with the FEA results. The AASHTO procedure over-estimated the strain values by about 30% when considering design trucks in the center of each of the two lanes. However, when considering a disabled truck parked on the shoulder and allowing two additional design trucks on the reference slab bridge, then AASHTO procedure gave similar strain values to the experimental and FEA results. The presence of various size potholes in one and/or two of the lanes at mid-span was also investigated subject to two possible loading conditions. This paper can assist engineers in predicting the behavior of reinforced concrete slab bridges.