Terex Tandem Sets 32 Girders in Two Shifts

Working in tandem, two Terex lattice-boom crawler cranes set a total of 32 concrete I-beam girders for highway bridges in two eight-hour overnight shifts.

The lifts were done as part of a project in which contractor C.A. Hull Inc., Walled Lake, Mich., replaced two 57-year-old highway overpass bridges in Bay County, Mich.

The original bridges that needed replacing had been built in 1958. After more than half a century of service, those original spans had become structurally deficient and the traffic volume using them has risen to 31,800 vehicles per day.

Because they cross over Interstate 75, which carries more than 50,000 vehicles per day beneath them, the project to replace them had to minimize disruption of traffic on I75.

“Time was definitely the biggest challenge affecting the lifts to place the I-beams on the piers,” said C.A. Hull project manager Rick Smith.

Work crews had just two eight-hour overnight windows to place the beams over the southbound and northbound lanes lanes of I-75. That meant Hull had to pick the right lifting equipment to efficiently position the beams. It chose Terex HC 165 and HC 110 lattice-boom crawler cranes.

Each of the 16 I-beams supporting the westbound and eastbound travel lanes of US-10 (32 beams in total) measured 104 ft. long and weighed about 43 tons.

“C.A. Hull required lifting equipment that offered the combination of high lift capacity and compact size to meet the congested space confinements of the job site,” recalls Vince Voetberg, Michigan manager for Jeffers Crane Service Inc., a member of the ALL Family of Companies, and a Terex Cranes equipment distributor in Michigan.

Smith reports considering a couple of ways to make the lifts. One option was to use a large hydraulic crane to set the beams, but beam size and weight would have required the work crew to reposition the crane multiple times to make the lifts, and I-75 would have to be closed before the crane was set up.

“We also had to place the false decking and fascia platforms while the interstate lanes were closed,” said Hull’s project engineer, Elias Motz. “We would have not been able to complete all the lifts in the time allotted to us using the single-crane option.”

The other option was using two smaller lattice-boom crawler cranes in tandem to place the beams. Hull planned to position one crane in the median between the northbound and southbound lanes of I-75, while the other would sit on the highway’s shoulder adjacent to the abutment wall.

“In this application, it was far more efficient to use the two-crane option in order to complete the lifts within our allotted time,” said Smith.

Voetberg added, “This is why C.A. Hull is one of the largest bridge contractors in Michigan. They consider all viable options and select the best alternative to efficiently and safely complete the project on time.”

Hull chose the Terex cranes because of their compact size, boom length, lifting capacity, and ease of assembly/disassembly. The plan called for the 110-ton-capacity HC 110 crane to sit in the median of I-75, while the 165-ton HC 165 was positioned near the abutment wall.

Hull trucked the cranes 90 miles from its Walled Lake office to the Bay City US-10/ I-75 project site. The HC165 took eight truckloads to deliver the crane, boom sections, and full counterweight. The HC 110 required only five truckloads.

Hull’s four-person crew needed less than five hours to set up each of the two cranes and have them ready for the lifts. “The cranes are easy to assemble and disassemble, which definitely saves us money,” says Smith. “They are very good for bridge construction.”

The Terex crawler cranes’ hydraulic system for installing and removing counterweight reduces rigging time and eliminates the need for an assist crane during assembly and disassembly.

“The HC 165 crane can lift its entire 108,400-lb. upper counterweight stack into position in a single operation,” said Voetberg.

Because of its narrow 18.6-ft. width, the HC 110 crane was set up in the median of I-75. Crews installed 110 ft. of boom and a four-part load line on the 110-ton-capacity crane. “The HC 110 crane remained stationary during the lift,” said Motz.

Crews positioned the HC 165, which has a 20.7-ft. track-to-track width and 165-ton lifting capacity, on I-75’s shoulder near the bridge abutment, then rigged it with 160 ft. of boom and a four-part load line. “This crane crawled during the lift to make sure the beams were properly positioned,” said Smith.

Freeway closures were allowed from 10 p.m. to 6 a.m. the following morning, in which either the northbound or southbound lanes of I-75 could be closed. For construction of one bridge spanning the closed southbound I-75 lanes, eight beams had to be erected and false decking and fascia platforms installed during that eight-hour closure.

The remaining eight beams, decking, and platforms spanning the northbound I-75 traffic lanes were placed the following night.

All the beams were positioned in the allotted time. “The cranes offered very smooth and reliable operation, which made them the preferred machines for this job,” said Smith. “The tandem-lift approach was very efficient, which is critical when you are working with Interstate lane closures.”

To help ensure the false decking and fascia platforms were installed in the eight-hour window, Hull used a 70-ton-capacity Terex RT 670 rough-terrain crane to help with the nighttime beam lifts and to make lifts from the top side of the project. “The RT 670 crane assisted in formwork placement and positioning of the rebar,” said Smith. “We like the crane’s mobility for assist work on bridge projects.”

The Terex rough-terrain crane has a 111-ft. boom that can telescope under load to efficiently perform multiple lift tasks. “Operators can choose from three steering modes to reduce turn radius, which is critical on congested construction sites like the US-10 bridge project over I-75,” said Voetberg.

In less than seven months, Hull’s crews transformed the two decades-old, structurally deficient bridges into sound, modern structures carrying more than 31,800 vehicles per day over I-75. The $6.4-million investment in advancing public safety and mobility will pay Michigan dividends for decades to come.