Malpaso Creek Bridge
Originally built in 1935, the Malpaso Creek Bridge is within several hundred yards of the Pacific Ocean and has been subject to over 80 years of chloride-laden winds.
The Problem
The build-up of chloride in the concrete has caused increasing corrosion levels in the substructure's reinforcing steel. Being a historic bridge, it was critical to maintain the original appearance. Therefore, conventional patching and repair techniques were not an option. In addition, the minimal environmental impact on the surrounding area was a critical need for the project. Caltrans contacted Vector to develop a repair procedure that would maximize service life and meet the other project requirements.
Our Solution
We repaired all spalled concrete areas and installed galvanic anodes in localized areas of higher expected chloride exposure. We then performed electrochemical chloride extraction for the entire repair area to remove chloride and reset the corrosion clock on the original concrete.
The Result
Repairs to the spalled areas were returned to their original appearance, maintaining the appearance of the historic structure. The majority of the chloride was removed from the concrete, and the protective hydroxyl layer around the reinforcing steel was significantly increased. This process resets the structure's service life and creates minimal environmental impact compared to other repair or replacement techniques.
Technology Used
These innovative products and technologies were used on this project.