2014 Issue

37 TRANSPORTATION INNOVATION | continued on page 38 not acceptable, others are invited to bid. CMGC keeps design deci- sions within the control of the owner, but with an overall reduced risk and increased flexibility to deal with that risk. In addition, the RFP process for CMGC is simpler and faster, and can be started earlier in the overall project. Long-lead items can be ordered earlier, and the overall construction time can be shortened. The $230 million Mountain View Corridor project is one example of a successful project constructed using CMGC. Accelerated Bridge Construction For the Utah Department of Transportation (UDOT), the use of ac- celerated bridge construction (ABC) technologies and techniques is not just a one-time event but a successful business practice that is rapidly becoming the norm, not the exception. Since first us- ing prefabricated bridge systems in 1997, UDOT has completed hundreds of projects that incorporated different ABC technolo- gies, ranging from full-depth precast concrete deck panels, bent caps and abutments to total superstructure systems and the use of self-propelled modular transporters (SPMTs) to replace bridges in a matter of hours. While several states are using ABC methods, Mr. Vasant Mistry, of the Federal Highway Administration Office of Bridge Technology, says that “Utah is an especially good success story.” Utah has moved more bridges with SPMTs than all other states combined. ABCmethods reduce overall construction time, decrease the need for complex management of traffic during construction (closed lanes, etc.), improve safety in the work zone for both the worker and the public, and decrease the overall impact to the travelling public by minimizing traffic disruptions. “The goal of all these in- novations is the same—to find a way to replace or fabricate a bridge in an extremely short time,” says Carmen Swanwick, UDOT’s Chief Bridge Engineer. After UDOT and the contractors learned how to use these methods successfully, ABC has resulted in construction cost savings on many projects. The most visible ABC technique employed in Utah has been the construction of an entire bridge superstructure off-site which is then moved into place in a matter of hours. UDOT has completed over two dozen of these “bridge moves.” Moving the bridge usu- ally involves a large, self-propelled modular transporter (SPMT), a platform with many individually-articulated wheels. One of the first of these projects was the replacement of bridge over I-215 at 4500 South in Salt Lake County. The superstructure of the new concrete and steel bridge was constructed adjacent to the roadway over a period of 4months in 2007, while the abutments for the new bridge were constructed underneath the existing bridge without impacting traffic. SPMTs were used to both remove the old bridge and to lift the new bridge into place over a single weekend. Road closures, normally anticipated to be about 6 months, were limited to two days over that weekend. While using SPMTs cost an additional $800,000, for UDOT this increase was offset by the substantial user cost sav- ings of $4 million. In the $103 million re- construction of I-80 in Salt Lake City, seven bridge structures were constructed at one loca- tion, referred to as the “bridge farm,” right. In just six weeks, each of these bridge structures were thenmoved down the corridor to their final locations, and skidded and lowered into place. It is estimated that this effort saved an entire year in the construction schedule, and saved $25 million in user costs. 4500 South Bridge, the First moved using SPMT