Bridges are complex structures, designed to withstand the significant effects of friction, vibration, and weather. Bridges installed in high-salinity locations are particularly susceptible to damage over time.
Bridge Materials and Salt Air
There are over 600,000 bridges in the United States, over 200,000 of which are made from steel. More than 330,000 are made from concrete and/or prestressed concrete, and more than 50,000 are constructed using other building materials. All of these materials, particularly steel, are susceptible to corrosion caused by salt air. High-salinity conditions can be present in a wide variety of circumstances including in seaside locations and above brackish water.
Why is Salt Air So Bad for Bridges
Airborne salinity is one of the primary drivers of corrosion. Corrosion, in turn, is the leading factor in the degradation of America’s bridges. Measuring the atmospheric conditions that lead to corrosion is difficult, but factors like Time of Wetness (TOW), pollutants, and airborne chloride all play a role in the rate of corrosion of bridge components. The “saltier” and more humid a bridge’s environment, the faster its most vulnerable components will corrode.
Bridge Maintenance in High-Salinity Locations
Continuous maintenance is a must for all bridges, but particularly for bridges located in areas with high airborne salinity. Not only are the bridges and bridge supports vulnerable to corrosion, so too are bridge-attached utilities and other bridge piping since many of these components are composed of steel, aluminum, and/or other materials that can corrode.
Maintaining a bridge in a high-salinity location starts with an anti-corrosion strategy. Ideally, the bridge itself will have been built out of corrosion-resistant materials; bridge-attached piping and utilities should also consider air quality before ever being installed.
Anti-Corrosion Measures for Bridges Exposed to Salt Air
Anti-corrosion techniques frequently used on bridge components include galvanization, wrappings, and coatings, to name a few. The exact solution required will depend on the location of the bridge, its age, its condition, and of course, the materials it is constructed from. In some cases, components that continue to corrode despite maintenance efforts should be replaced with components of a different material such as PVC or “weathering” steel.
The maintenance required for bridges subject to saline exposure is more extensive than that of other bridges. On top of annual or bi-annual maintenance activities such as painting, coating, and/or cleaning, these bridges should also be subject to at least one thorough inspection a year. Professional bridge and bridge utilities inspections can spot anything from corroded attachment joints to structurally unsound suspension lines.
Aptus is a leader in bridge-attached piping maintenance. We work on bridges in almost every state, many of which are located in areas with constant saline exposure. On these structures, our decades of experience handling complex bridge-related issues is particularly useful.
Are you looking for more information on how to move forward with a more comprehensive bridge maintenance strategy? Reach out to the team at Aptus today.