3 Designs for new I-5 Bridge

After reviewing various designs for the new Interstate 5 bridge from Portland to Vancouver, Governors Gregoire and Kitzhaber have come to terms on three intricate designs. One design is a cable-stay bridge which is going to be an estimated $40 million cheaper than the old CRC design that is currently existing. The second design is composite deck truss structure style that is will cost nearly $100 million less than the bridge that is now standing. The third and final design is a tied arch design that will cost close to $10 million less than the CRC style.

The governors have ordered the Departments of Transportation to discontinue any more design work on the new bridge. The reason each of these bridges will be cheaper in cost is because they all require fewer bridge piers in the water. Apparently, due to the height of the cable-stay and tied-arch design, these two designs would require approval from the Federal Aviation Administration, because of the proximity of Pearson Air Field nearby. In addition, all three design proposals will require 95 feet of passing clearing for ships passing through. Overall, it seems that the composite deck is going to cause the least amount of headaches, because the other two designs will require straighter alignment, which also means that engineers would somehow have to widen the curve of the freeway. This could be a problem though because the wider freeway would most likely run right into downtown Vancouver.

The current estimated cost of the new bridge is $3.6 billion, and would replace the two three-lane draw bridges, with ten lanes, revamp seven interchanges along five miles of freeway, and would extend the Portland light-rail transportation into downtown Vancouver. Planners intend to have a three-way cost split between federal government, and two-state local revenue which will be generated by bridge tolls.

Being from Vancouver and having to commute to Portland for work everyday in previous jobs, I think this new bridge will have its benefits, as well as its detriments. The larger size is going to reduce the rush hour traffic flow, and the light rail will be a huge advantage, but the tolls are going to cause people to commute over the I-205 bridge, which will create more traffic on the east side. I understand that this bridge will create lots of new work, but is it really necessary? Are this new bridges benefits going to outweigh the costs?

http://www.columbian.com/news/2011/feb/03/engineers-report-endorses-crossing-project/