The sufficiency rating is a method of evaluating highway bridge data by calculating four separate factors to obtain a numeric value that is indicative of the bridge's sufficiency to remain in service. The result of this method is a percentage in which 100 percent would represent an entirely sufficient bridge and zero percent would represent an entirely insufficient or deficient bridge. The national average sufficiency rating for bridges is 85 points.
The Gerald Desmond, Schuyler Heim, and Vincent Thomas bridges connect the ports' Terminal Island with the mainland on the east, north and west, respectively.
The Gerald Desmond Bridge, built in 1968, carries nearly 60,000 vehicles each day. It received a Caltrans rating of 62.3 points according to information from the federal National Bridge Inventory.
The Schuyler Heim Bridge, built in 1948, carries slightly more than 20,000 vehicles a day. It received a rating of 27.9, putting in the bottom 0.09 percent of all rated bridges in the state.
| The Schuyler Heim Bridge received one of the lowest sufficiency ratings in the state. Adjacent to the rail-only Badger Bridge (left), the Schuyler Heim connects northern Terminal Island to the mainland. |
The Vincent Thomas suspension bridge, built in 1963, carries nearly 45,000 vehicles a day, has a rating of 56.7, according to NBI.
A low sufficiency rating does not immediately indicate that a bridge is unfit or unsafe for use. Many criteria other than structural integrity are used to formulate the rating and a rating may be dragged low by non-structural problems.
In addition to low sufficiency ratings, each bridge also meets the criteria to be defined by the federal labels of 'structurally deficient' and 'functionally obsolete.'
The 'structurally deficient' label is based on six inspection categories. A low score in any of these categories qualifies the bridge for listing with the label. The Gerald Desmond and Vincent Thomas each scored below the label threshold in the 'deck' category, indicating problems with the road surface over the bridge. The Schuyler Heim scored low in the 'superstructure' category, indicating problems with the structure of the bridge above the road deck.
The 'functionally obsolete' label is based on five inspection categories. All three of the bridges scored below the label's threshold in the 'deck geometry' category, indicating that the road layout is not adequate for the current traffic load. The Vincent Thomas and the Schuyler Heim also scored below the label's threshold in the 'underclear, vertical and horizontal' category. This category indicates if the clearances under the bridge are adequate.
The Gerald Desmond and the Schuyler Heim are both slated for replacement, at a cost of $824 million and $426 million, respectively. While Long Beach port officials have obtained partial funding from government sources, neither project is yet fully funded.
