Breaking New Ground On Equity
By Luke Carothers
Interstate 5 runs roughly parallel to the West Coast of the United States, linking its largest cities from the southern border with Mexico to the northern border with Canada. It carries a tremendous amount of freight annually, and connects regional and national markets with international ones in Mexico, Canada, and the Pacific. However, despite the importance of this trans - portation corridor, several critical connections are in need of renovation, repair, or even replacement. One of these critical connections is the Interstate 5 Bridge across the Columbia River, which links the states of Oregon and Washington. While Interstate 5 was created in 1956 as a part of the Interstate Highway System, its construction made use of existing infrastructure. One such piece of infrastructure was the existing Interstate Bridge over the Columbia River, which was opened in 1917. In 1958, a second twin bridge was constructed, and, with its opening, each bridge carried one-way traffic. As the surrounding communities have grown in the last half century, the Interstate 5 Bridge has come to represent a vital link for people, goods, and services. However, this vital link has become outdated, and the problems that stem from the structure’s age are driving the conversation to replace the aging piece of infrastructure.
The outdated state of this bridge has serious ramifica - tions for the people who rely on it for their day-to-day lives. There are a significant number of safety issues that arise from the bridge’s design and age. Currently, the bridge is one of the highest crash locations in Oregon’s interstate system, and it averages 7-10 hours of congestion during the morning and evening commutes. These problems largely arise from the bridge’s lack of shoulders, lifts, and closely spaced interchanges. To further add to the congestion, the bridge lies between the Port of Portland and the Port of Vancouver, which means that over 13,500 trucks crossed the bridge in 2019, representing just under 10 percent of daily traffic. The issues of freight congestion will only be exacerbated by future growth, and experts predict that freight tonnage will double by 2040. Further stress is added by the fact that there is currently no high capacity transit connecting Portland and Vancouver. While there is a walking and biking path on either side of the bridge, its small 3.5 foot width is not capable of safely supporting any meaningful amount of foot or bicycle traffic. The conversation to replace the bridge has been going on for almost 25 years. Previous efforts to update the structure failed in 2014 because
Courtesy of the Interstate Bridge Replacement program
the Washington state legislature declined to take up the funding pack- age. However, despite this setback, the problems posed by the bridge were only getting worse. With the Portland-Vancouver area’s average growth of just over 13 percent, the problems that exist as a result of these outdated structures will only be exacerbated by a bigger popula - tion. Furthermore, the current design is a lift bridge built on timber piles in a silty river, which poses significant problems if it were to experience an earthquake. The lift bridge style is so outdated that there are less than 20 still in service throughout the United States. This need was recognized in 2019 when Governor Kate Brown of Oregon and Governor Jay Inslee of Washington agreed to create the Interstate Bridge Replacement Program (IBR). The goal in creating the IBR program is to replace the Interstate Bridge over the Columbia River with a modern, seismically resistant, multimodal structure. In doing so, this corridor will see improved mobility for people, goods,
april 2022 csengineermag.com
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