Bridging to a better future
By Bill Killeen
The vast majority of bridges in need of permanent replacement or temporary replacement while in repair are part of our secondary, local and rural road systems. These bridges connect the backbone of a vital network of roads that support sustainable economic growth across the country. By maintaining these roads, we enable a flow of commerce in which farmers can bring crops to market and small and mid-sized businesses can transport products to local and export markets with logistical efficiency. The result? More vibrant local economies that are key contributors to a more competitive national economy.
The challenge, as we all know, is replacing secondary, local and rural bridges quickly and cost-effectively – a responsibility shouldered by under-resourced state, municipal and local governments. Ironically, a current model that is widely used has been shown to increase project costs. In this model, a governing agency engages the services of an engineering consultant to design and develop a bridge replacement project, using conventional build-in-place construction. The engineering firm is tasked with developing a design compliant with federal standards for width, length, loadings, sight distance and other factors, which tends to drive up costs.
There are changes and alternatives to this approach that can keep costs in check without compromising project integrity. These include:
Easing geometric standard requirements where appropriate – In our experience, it doesn’t make sense to impose a one-size-fits-all requirement. It often results in unnecessary costs, such as a 48-foot wide bridge at a site that would be well serviced by a 24-foot wide bridge for decades to come.
Eliminating restrictionstied to state and federal funding – Local governing agencies should be allowed to size and design bridges that are appropriate for their roadways, while still being able to obtain federal and state funding.
Considering solutions that minimize engineering design time – The use of prefabricated modular bridge components of a component off the shelf nature, for example, would significantly simplify the process and thereby shorten the time needed to design and engineer an effective bridging solution.
Supporting the principles of prefabrication and modularity– Through prefabrication and modularity, it is possible to construct a bridge in a much shorter period of time (weeks versus months or longer), resulting in the economic and environmental benefits of less disruption to the flow of traffic and commerce. Further, a bridge constructed from prefabricated, modular components, whether steel or concrete, tends to be of higher quality than one constructed by conventional means. This is due to fact that the prefabrication process is required to take place in a highly controlled quality assurance environment.
The advantages of prefabrication and modularity can be realized even on projects that do not require total bridge replacement. For example, if only the deck needs to be replaced, then the new deck can be designed to use prefabricated, modular technology without compromising design integrity and the life of a road deck system.
Taking steps like those outlined above can result in much more economical bridge replacements, with the added advantage of freeing up funds for use on other bridge projects. Of course, as head of one of the world’s leading providers of prefabricated, modular steel bridging, I am biased toward the use of modular prefabrication. My bias comes from years of seeing the many benefits of this bridging approach.
The concept of modular prefabrication stands in good company. The Federal Highway Administration under the ACTT program and the American Association of State and Highway and Transportation Officials under the TIGG program both support and advocate the use of prefabrication and modularity for all of the reasons previously stated and more. Both organizations have identified the significant advantages of prefabrication and modularity when designing and building bridges.
Particularly in the current economic environment, we must remain steadfast in our support of the vital transportation infrastructure that serves small and mid-sized communities – by advocating the development and adoption of more cost-effective measures. Every step in this direction counts. Connecting farms, businesses, families and their communities were goals of President Franklin Delano Roosevelt when he created the Work Projects Administration. Many of the bridges that now need replacing were constructed during the 1930s under this historic program. Our secondary, local and rural roads were indeed an important part of American history – and remain key to our country’s future.
Bill Killeen is the president and CEO of Acrow Bridge.