What is the work?
Crews replaced a 28-year-old expansion joint that spans the width of northbound and southbound Interstate 5. The project was required as concrete surrounding the joint had deteriorated, which could lead to a failure and popping up into traffic creating a safety hazard for the drivers. The synthetic rubber seals were also broken allowing water to leak through the joints, washing away soil under the bridge. WSDOT replaced the concrete headers around the expansion joint. Crews will replace the rubber seals with a silicone-based seal.
Why was replacing the expansion joint necessary?
Expansion joints are a critical part of a bridge’s infrastructure. The joints allow the bridge to move and flex with changing traffic and weather conditions. Joints that fail can unexpectedly pop up into traffic, resulting in an emergency closure of lanes to replace or repair them. Since no one can plan for a failure and subsequent emergency closure, WSDOT replaced the joint under scheduled closures before it failed.
Why can’t the expansion joints be replaced during overnight closures?
Our goal with every project, including this one, is to get the construction work done as quickly as possible with the least effect on the traveling public. This particular type of work required concrete be removed and repoured in the same timeframe. After careful consideration, we determined condensing the work into two admittedly difficult travel weekends was still better for motorists than extended night closures. This was especially given the challenging location of this expansion joint. It runs across all six lanes of I-5, the US 101 on and off ramps, the Deschutes Parkway on-ramp and the Henderson Avenue on-ramp. By breaking the work up into two weekends, we were able to minimize impacts to drivers.
Why can’t you do this work during the winter, like between Christmas and New Year’s when people take time off? Isn’t traffic lighter at that time of year compared to summer travel?
The number of vehicles on I-5 is only slightly lower between Christmas and the New Year, when compared to summer.
Also, the odds of poor weather are much higher in the winter. To get a good-quality product, we need weather that is relatively dry and warm. Although it is possible to protect newly poured concrete around the expansion joints from the heavy precipitation we often experience in the winter by placing tents over them, we must also consider the increased risk of more severe weather including freezing temperatures, snow and ice. Freezing temperatures would prevent crews from pouring concrete. If we scheduled this work to occur in the winter there is an increased risk of delays or work cancellations. Since we can’t predict when these joints might fail, we needed to schedule the replacement work to occur as soon as possible during the best possible weather conditions.
In addition, WSDOT’s first priority is safety for drivers as well as construction and maintenance crews. Wet and cold weather increases the risk of injury to workers and creates difficult driving conditions for motorists.
Has WSDOT made repairs to this joint in the past?
This bridge on Interstate 5 was originally built in 1956, and rebuild and widened in 1986. We replaced the concrete that surrounds the bridge joint and will replace the waterproof seal that was installed in 1986. There have been numerous temporary repairs on this particular bridge joint in the past 5 years. The most recent repair was in February, 2014.
How many other joints on I-5 need to be replaced?
At present, no other expansion joints are scheduled for repairs on I-5 in Thurston County. However, WSDOT’s highways are aging and our crews monitor the expansion joints on all our bridges closely to monitor their conditions and look for signs of stress. This particular bridge joint was folded into the I-5 – Vicinity Tumwater Blvd to Gravelly Lake Dr – Paving project.
The next expansion joint on our radar in the area is on the I-5 bridge spanning Pacific Avenue on Olympia. That expansion joint, too, is aging and requiring multiple repairs. At present we have no funds to replace that joint, so we will continue to keep it operational as best as we can.