Why Bridges are Often Left Unpaved When Roads are Repaved

Bridges play a crucial role in modern transportation networks, connecting communities and facilitating the flow of traffic. However, when it comes to the maintenance of interstates and highways, bridges often get skipped in the repaving process. This article explores the reasons behind this practice, highlighting the structural considerations, maintenance schedules, cost and logistics, and the unique aspects of bridge engineering.

Structural Considerations

Bridges and roadways, while both key elements of transportation infrastructure, have vastly different structural requirements. Bridges are designed to support heavy loads and manage water runoff, which can significantly affect their material and maintenance needs. Unlike asphalt, which is less durable under flexing conditions, concrete is more resilient. Consequently, repaving a bridge with asphalt involves different techniques and materials, making it a more complex process.

Bridges require specialized maintenance schedules that don’t always align with those of roadways. They may be inspected and repaired independently to ensure safety and efficiency. This separation in maintenance plans can lead to the simultaneous repaving of roadways and bridge maintenance, but not necessarily at the same time.

Different Maintenance Schedules

Managing bridges and roadways separately is often more efficient for several reasons. Repaving roadways and bridges involves different schedules and budgets. For instance, roadways may need resurfacing more frequently due to heavier traffic and increased wear and tear. Bridges, on the other hand, may have a lifespan that extends 10 to 20 years beyond that of typical roadways, depending on their construction.

The specific funding for bridges and roadways comes from different sources. This means that bridge maintenance funds cannot be used for road repaving, and vice versa. While it is possible to use both funds for the same project, it is not a common practice. The utilization of separate funding streams ensures a more targeted and effective allocation of resources for each component.

Cost and Logistics

Repaving a bridge involves more complex logistics and higher costs due to the need for specialized equipment and materials. This includes heavy machinery, specific construction techniques, and potentially temporary detours or traffic management measures. In contrast, repaving roadways involves more straightforward procedures and lower costs.

For example, paving a bridge might require significant traffic rerouting and careful planning to minimize disruption, whereas repaving a highway can be done in less intrusive ways. Additionally, the environmental and traffic impacts of repaving a bridge must be carefully managed, which can add to the overall cost and complexity.

Traffic Management and Condition Assessment

Closing a bridge for repaving can significantly impact traffic flow, leading to increased travel time and potential accidents. To minimize disruptions, authorities often choose to repave roadways while leaving bridges unchanged. This approach ensures that the overall transportation network remains functional and safe during the repaving process.

The condition of the bridge is another critical factor. If the bridge has recently been maintained or its surface is still in good condition compared to the roadways, repaving may be postponed. This strategic approach allows resources to be allocated more efficiently, targeting areas that are in the most dire need of maintenance.

Engineering and Funding Considerations

Bridges and roadways are engineered differently for various reasons. Bridge decking requires different materials, structures, and maintenance schedules compared to asphalt surfaces. The funding sources for bridges and roadways are distinct, making it challenging to combine the two.

The functional lifespan of bridges and surface roads varies significantly. Bridges may require replacement every 50 to 80 years, whereas roadways typically need resurfacing every 10 to 20 years. This difference in lifespan further contributes to the separate maintenance schedules and funding.

Conclusion

While bridges and roadways are integral to the transportation network, the unique needs and lifecycle of these structures necessitate separate maintenance and repaving schedules. Understanding these differences is crucial for efficient and effective infrastructure management. By addressing individual components with tailored maintenance plans, authorities can ensure the longevity and safety of both roadways and bridges.