Evaluating bridges to enhance capacity and improve safety

Hastings District Bridge Strengthening

The more products you can move, and the faster you can move them, the better. In the Hastings District of New Zealand, it had become apparent that high productivity motor vehicles (HPMVs) hauling freight were placing increasing stress on bridges in the region. Plus, many haulers had to devise circuitous routes to avoid bridges underrated for their vehicles. In response, Hastings District Council sought to determine the capacity of bridges on strategic routes across their road network to accommodate HPMVs and identify any repairs or upgrade works required to allow HPMVs to use these routes.

Our job? Evaluate more than 65 bridges across the region. We needed to confirm the capacity of each structure and outline strengthening options, risks, mitigation strategies, and improvement cost estimates for each structure that failed to meet the required HPMV ratings. In our surveys, we found 47 bridges required no remediation. Of those requiring strengthening, seven have been completed, with 11 more being evaluated for strengthening.

Working on legacy structures, like bridges, is always complex with occasional sleuthing required. For example, for the Kuripapango Bridge, our investigations revealed the bridge wasn't constructed according to its original design. This required a careful reexamination of the bridge’s structural characteristics to inform our strengthening and upgrading plan. With more goods transported more quickly, by more direct routes, commerce in the region can keep pace with demand.