Can you have a regulatory plan for bridge construction that doesn’t include the bridge? Too often we are pulled into a project with a predetermined regulatory plan, and the bridge design has been left out of the discussion. The requirement to build a bridge is typically well understood – you either have to cross something or you don’t – but the method to gain approval for construction of that bridge can present a labyrinth of options with cause and effect implications with each decision. Early engagement of your bridge designer with your project team, especially the regulatory specialist, will make the process smoother, more cost effective, and result in quicker approvals.
This commonly boils down to two different approaches: 1) complete avoidance which results in a longer structure, or 2) planning for the impacts created by a smaller structure.
Owners often want a fast regulatory process that usually means complete impact avoidance and a longer span. Bridges can be prefabricated and placed onto abutments without using falsework, but construction and scour protection of those abutments need to be considered in the regulatory plan. Longer span bridges and curved or skewed alignments can eliminate prefabricated superstructure options, which points back to falsework and temporary construction impacts.
Reducing the span of the structure to simply meet the conveyance requirements can present lower construction costs, albeit with potentially greater impacts. A feasibility study during preliminary design should present you with short-span bridges that consider the cost of impacts AND long-span bridges. Both options should include an estimate of mitigation fees associated with each option, because those costs are directly affected by the structure type. At the preliminary design phase, a reasonable estimate for scour should be identified. Finding out the abutments will be subject to 20 feet of scour is a game changer in terms of impacts due to excavation setbacks or riprap placement.
Both approaches have merit; whether you seek complete avoidance or decide to manage your impacts, the critical point is the importance of including your bridge designer in the discussion to provide guidance about the cost, schedule and feasibility of your regulatory plan for your bridge project.
