Before its primary job installing a transmission pole could be performed, TNT Crane & Rigging had to solve several problems. D.Ann Shiffler reports.
Sometimes you just must improvise. This was the case recently in New Braunfels, TX, where TNT Crane and Rigging was preparing to perform drilling work and install a high line pole with the company’s 120-ton capacity Liebherr LTM-1085-5.1 for its client Irby Construction.
The problem was that the jobsite was on the other side of a canal. There was a bridge over the canal, but its capacity was deemed too low to handle the weight of the crane and the drilling rig.
TNT’s solution, according to Anthony Dues, branch manager of crawler cranes and projects division, was to bring in a Manitowoc Model 18000 to lift the drilling rig and the LTM-1085-5.1 over the canal to the jobsite.
“This was the most cost effective and fastest solution to complete the job and stay on schedule,” Dues said.
With this plan in place, TNT’s crew dealt with several challenges including less-than-ideal ground conditions and uncooperative weather. The Manitowoc crawler had to be built in a cow pasture.
“After several rainstorms, it became very muddy and we had to build a mat road to get all the trucks and components in and out of the site,” said Dues. “The 18000 was positioned on a double layer of timber and steel to get the ground bearing pressure low enough so as to not jeopardize the levy that was in front of the crane.”
The Manitowoc 18000 crawler was rigged with 280 feet of main boom with the 140-foot super lift derrick and 600,000 pounds of counterweight on the superlift tray.
Center of gravity checks
The Manitowoc 18000 crawler, with a capacity of 850 tons, was rigged with 280 feet of main boom with the 140-foot super lift derrick and 600,000 pounds of counterweight on the superlift tray. The drilling rig was lifted and set in place utilizing a two-bar system and the Liebherr all terrain crane was lifted and placed using a three-bar system. These spreader bar systems helped the operator keep the machines’ center of gravity in check.
The drilling ring weighed 125,448 pounds and the Liebherr all terrain crane weighed 158,852 pounds. The drilling rig was lifted and placed first. Lifting, moving and placing both machines was a slow and steady process that involved precision crane operations. Signal persons on the ground helped guide the loads on either side of the canal.
The morning the crane was moved turned out to be foggy, although it burned off pretty quickly as the day dawned. Once the crane cleared the canal it was carefully lowered onto the roadway to the jobsite.
“The final set point on the other side of the canal was at a 220-foot radius,” Dues explained.
Four jobs in one
Once the all-terrain crane was in place it was rigged out with its full counterweight and 197 feet of live boom scoped out. The AT’s scope of work was to assemble and erect the 170-foot tall transmission pole that was built in four sections. The heaviest section, the base, weighed 30,000 pounds. TNT also dispatched a boom truck rigged with a man basket to the jobsite to help with the pole assembly.
The AT’s scope of work was to assemble and erect a 170-foot tall transmission pole that was built in four sections. The heaviest section, the base, weighed 30,000 pounds.
Once that job was complete the big Manitowoc 16000 crawler went back into action again, lifting the Liebherr all terrain crane and the drilling rig back over the canal in the reverse order. All the equipment was then disassembled and trucked out.