The first steel girders, which are beams that support the deck for the new Grand Avenue traffic bridge, are scheduled to arrive in February and will span from the abutment in the Hot Springs Pool parking lot, over Interstate 70 and finish over the Colorado River.

The new tub steel girders for the bridge were fabricated by two different U.S. companies – Utah Pacific out of Lindon, Utah, and Hirschfield Industries out of San Angelo, Texas.

A girder is large beam or compound structure used for building bridges. A tub girder is a trapezoid-shaped steel girder that consists of two angled webs (side panels), short top flanges on top of each web and a wide bottom flange connecting the webs together.

Last summer, 14 steel girders were erected for the new pedestrian bridge. These girders span from 62 to 105 feet and weigh between 27,000 and 50,000 pounds.

The steel girders for the new traffic bridge span from 84 to 127 feet in length and weigh between 81,000 to 121,000 pounds. The traffic bridge girders will be erected in two phases, with 14 arriving next month and seven arriving to complete the connection to the south side of the bridge during the August detour.

CDOT’s steel inspector, Jim Jones, has visited the Hirschfield plant several times to verify that the work is satisfying CDOT’s quality control program. While in Texas, Jones inspects the welding process, how the girder pieces are fitting together and verifies that Hirschfield is abiding by the “Buy America” requirements. The Buy America program is a requirement of state-funded transportation projects, and ensures that the entire steel manufacturing process, from buying steel to fabricating the girders, is completed in America with American-made steel.

The first set of engineered design drawings were sent to Hirschfield and Utah Pacific in fall 2016. The lead time to receive a finished project can range from three to nine months, depending on how quickly steel is delivered to the fabricators.

When the girders are complete, they will be loaded onto large flatbed trailers that contain an additional dolly, or extra set of wheels on the back end, to support the length and weight of these massive structures. The transport of the girders requires one driver in the semi-cab and one in the dolly to control the back-end and assist with turning. You will see the girders sitting on trailers at the old rest stop on I-70 between Exits 114 and 116 in the coming weeks.

To erect these huge steel girders over I-70, there will be several nights of the I-70 detour using Sixth Street. Stay tuned for updated information on steel girder erection and traffic impacts in next week’s Answer Man.