Caltrans, University of California and Cristie Constructors all designed a potential retrofit for the columns. C. H. Bull Company worked with Caltrans engineers in designing a hydraulic jacking system to test a number of different column repairs. We supplied over 1,000 tons of jacking force to be used in the testing. With the jacking system installed, they were able to exert forces both laterally and vertically on the sections and were tested to failure.
The three possible retrofit solutions were tested and one tested far superior to the others. It is because of these tests many overpasses and bridges have been retrofitted in California and around the Western United States.