Barnhart was hired to set 21 bridge girders on three different spans on an interstate junction in Mississippi. Barnhart engineers developed an innovative system using two 9-line, single wide SPMTs and two 6-line, 1½ wide Goldhofer SPMTs.
The girders were brought in on a closed roadway for the team to lift and set. The pre-stressed concrete girders weighed between 138,000 and 203,000 lbs. The longest ones were 170’ in length.
Barnhart used a 1,000 Ton Slide System to safely control the lateral shift of the girders and air hoists to compensate for various placement heights.
The two sets of PSTs were spaced 133 feet apart and separated by the new bridge. One set was on a Hwy 51 bridge during the lifts while the other PSTs were on an I-20 bridge. The SPMT system allowed Barnhart to relocate the lift system to the next girder while meeting the loading requirements. Despite delays with girder delivery, Barnhart completed the project ahead of schedule and under budget.