Boise-based contractor Concrete Placing Co. began the Garrity Interchange Bridge project last summer and continued work through the winter
By Rebecca Ragain
The population of Meridian, Idaho, grew 96 percent between 2000 and 2009. The nearby towns of Nampa and Caldwell grew 57 and 67 percent, respectively, in the same time frame.
It’s no wonder that the region’s highway system was due for improvement.
Most of the area’s freeways and bridges were built in the 1960s, said Idaho Transportation Department spokesperson Reed Hollinshead.
“Population growth and growth in traffic over the last 40-plus years has outstripped the ability of that system to continue to serve it [the area] efficiently,” said Hollinshead.
Interstate 84, the main connector between Caldwell and Meridian, sees the highest traffic volume in the region. To accommodate growth, ITD has identified nine projects along the I-84 corridor between Caldwell and Meridian; several sections of interstate are being widened, which in turn requires a number of bridge and interchange improvements.
Several of these projects are underway now, despite winter conditions. One of them is the Garrity Interchange Bridge project in Nampa, which reconstructs 0.9 mi. (1.4 km) of I-84 and replaces two bridges at the Garrity Interchange with a single bridge.
Boise-based contractor Concrete Placing Co. began the Garrity Interchange Bridge project last summer. The first phase was to build the median section of the new bridge between the two existing structures, so that traffic could be moved onto that section when the westbound bridge was removed, which happened in July.
Throughout late summer and fall, crews built the new westbound portion of the bridge, then moved westbound traffic onto it while eastbound traffic remained on the median section. In December, the original eastbound structure was demolished.
The old structures were three-span bridges with piers in the middle of the road underneath; part of Concrete Placing Co.’s contract was to remove those piers. The new bridges are comprised of single-span, pre-cast concrete girders with a cast-in-place deck. The embankment is new MSE wall.
Currently, crews are building the sub-base on the eastbound roadway and constructing the new eastbound bridge, working on the deck as weather allows.
“Doing the concrete work like that is not easy in the winter, but it’s not unheard of,” said Mike Burke, a spokesperson for Concrete Placing Co. “It’s a fairly mild winter here.”
Concrete Placing Co., which is primarily a bridge-building and paving company, has its own fleet that includes Link-Belt cranes and Ingersoll Rand forklifts.
The primary contractor had about 40 workers on the job when the $15-million project was at its peak last fall. In addition, approximately 10 subcontractors were employed, including a local office of Knife River Corporation that did the earthwork.
To date, the project has proceeded as planned, with no unexpected challenges, said Burke: “Just the logistics of getting in and out of the construction zone while keeping traffic moving is the biggest challenge.”
The project is scheduled for completion this summer, with three lanes open in each direction over the Garrity Interchange Bridge. The plan for the future is to have four lanes in each direction from the Garrity to Meridian interchanges.
But that depends, as usual, on funding.
This series of I-84 improvements is funded by the GARVEE Transportation Program, which uses bonds to expedite interstate improvements. As of December, the Idaho Legislature had approved $693 million in bond authorizations; the program is projected to wrap up after a final $162 million is allotted.
Concrete Placing Co. is currently working on other I-84 projects that are funded by GARVEE, in addition to the Garrity Interchange Bridge project. These include a $22-million project to widen the interstate between the Franklin Boulevard and Garrity Boulevard interchanges and a $36-million project to rebuild and widen I-84, both east- and westbound, between the Cole and Broadway interchanges in Boise.
Burke said that Boise-area contractors have been fairly fortunate, staying busier than their peers in other regions, because a lot of projects were already in the works when the recession hit.
But that safety net will be gone once the GARVEE program is finished, unless the state legislature approves new funding for transportation, said Burke. Otherwise, he says that IDT will be in the same boat as other states’ transportation departments: “They need more money to get more work going.” CEG