Load Rating Assessment of Three Slab-Span Bridges over Shingle Creek

Principal Investigator:

Ben Dymond, Assistant Professor, UMD-Civil Engineering


Project Summary:

The volume of freight transported via trucking was projected to grow by 70% between 1997 and 2020 (Mallett et al. 2004). Furthermore, businesses and individuals have continued to demand more flexible and timely service, which has increased the importance of an efficient and reliable freight transportation system. To this end, the demand placed upon bridge infrastructure has grown. MnDOT frequently conducts special (single trip) permit load ratings in accordance with state and national standards to establish efficient haul routes around the Metro area to meet these demands. Permit load rating is a review of the safety and serviceability of a bridge, which is conducted so that vehicles above the legally established weight limitations may pass over a structure safely. MnDOT has identified a critical trucking corridor on I-94 and I-694 that includes traversing over one of three concrete slab span (C-SLABS) bridges crossing Shingle Creek in Brooklyn Center, MN (Bridges 27909, 27925, or 27926). Overweight permits have been granted for vehicles similar to MN standard permit trucks A, B, and C to cross these structures; however, passage has not been granted for some larger vehicles (Gao 2019). These three bridges are not scheduled for significant future improvements or replacement. The main objectives of this project are to: (1) Collect data from field testing to characterize the behavior (strains, deflections, dynamic response) of the C-SLABS under a known truck load. (2) Further evaluate live load response and bridge capacity using a refined method of numerical analysis validated using field test data. (3) Assess the impact of the measured and modeled live load response on bridge behavior, permit load rating, and bridge capacity. (4) Contribute to the development of guidance related to permit load rating these three C-SLAB structures.


Project Details: