ON THIS DAY: January 28, 1977, Massive crack threatens I-79 Glenfield Bridge with collapse

NEVILLE TOWNSHIP, Pa. — A riverboat captain passing underneath the 5-month-old Glenfield Bridge spotted a gaping crack on one of the span’s 300-foot steel girders. The bridge, over the backchannel of the Ohio River linking I-79 to Neville Island, was closed immediately and remained closed for three months.

The ten foot high, 3 inch thick steel girder was split from top to bottom with the fissure in the bottom flange measuring three inches wide.

Dravo Corp. Captain Steve Muick was breaking ice in the back channel at the helm of the crane-equipped barge “Ranger,” when he spotted the compromised girder. He was checking to see if the boom of the crane would clear the bottom of the bridge and called State Police as soon as he saw the fractured girder. They barricaded the bridge immediately.

The girder is the outermost support in the northbound lanes, but bore the weight from all six lanes, resulting in the span’s complete closure.

Engineers said the averted catastrophe was first discovered during a bitterly cold noon blizzard. Wind gusts of up to 58 mph joined with arctic air that was already 18 degrees below zero. Ambient air temperatures dropped over 20 degrees in one hour.

The five-month-old bridge cost $28.5 million when it opened in late 1976 to much fanfare as the final link in the 180-mile Interstate 79.

Built by the Bristol Steel and Iron Company of Virginia, which offered the lowest bid and beat out local companies for the project, the bridge was supposed to last at least 50 years.

Touted as Pennsylvania’s Bicentennial gift to Pittsburgh, Allegheny County Commissioner Jim Flaherty was quoted on opening day as proclaiming, “It’s a great pleasure to stand on a bridge and not have to worry about it falling.”

State Transportation Secretary William Sherlock immediately launched a full-scale investigation in cooperation with PennDOT and the Federal Highway Administration (FHWA).

During the investigation it was believed that defects in the steel may have been caused by an electroslag welding process. As a result, the FHWA prohibited the use of electroslag welding on all tension members in future bridges.

Repairs to the bridge took three months and were completed by the construction company at its own expense. Hydraulic jacks were used to force the crack closed and heavy plates were bolted over the damage to create a splice. No other repairs or reinforcements were added.

The bridge reopened on March 31, 1977.

Motorists were relieved because the nearby Sewickley Bridge had also been closed around the same time when the extreme cold weather worsened existing known structural damage. It was feared that the extreme cold could make the weakened steel even more brittle.

The combination of both bridge closures compounded traffic problems and enraged motorists. During the closures, the next nearest Ohio River crossing points were in Ambridge or McKees Rocks, about 17 miles away, with no alternatives in between.

The closures also afflicted communities up and down the river to heavy truck traffic diverted from I-79 and caused economic hardships in other business districts that had previously been busy.

The backchannel bridge and its accompanying 3,700-foot steel arch over the main channel have received huge repairs over the years. Hairline cracks required $1.8 million of repairs in 1999. Crews bored holes into the ends of the cracks to relieve stress and prevent them from spreading. Additional repairs in 2003 resulted in more steel plates being welded on.

Both portions of the bridge were repaired again in 2020.