Client: CF Industries
Location: Sergeant Bluff, IA
Date of Completion: June 2015
Boh’s portion of the $1.7 billion capacity expansion project at CF Industries’ Port Neal Nitrogen Complex was to construct a 630-foot-long bridge that connected the plant to a collector well being built by another contractor on the edge of the Missouri River. Although the Boh team enjoyed pleasant weather with temperatures in the 50s and 60s for the first couple weeks of the project, an arctic blast soon descended on the region, bringing temperatures in the low 20s that dropped to zero or below with the wind chill factor.
“Once the ground started freezing, there was a layer of permafrost about a foot thick that meant the piles didn’t sink in when we placed them,” Tri Le, Boh’s field project manager, said. “Whenever we started the hammer, the pile wanted to bounce around in every which direction. The template held it in place and did what it was designed to do.”
The template guided placement of one bent comprising three steel pipe pilings, each 18 inches in diameter and ranging from 90 to 108 feet long. The bridge includes 27 bents, with number one closest to the well, and number 27 located at the edge of the plant property. Boh started at the ninth bent and progressed the work in the direction of the plant, to afford the well contractor more room to work. The entire bridge (which varied from 22 to 47.5 feet in width) and the well was constructed within a 50-foot-wide ribbon of land.