WATCH | Major Pittsburgh bridge reopens after demo, single-day slide replacement

The Dutch specialty transport firm said it was the heaviest bridge the firm ever moved in the USA. 

A close-up of the Mammoet skid shoe system used to slide the Commercial Street Bridge 31 metres into position. Photo: Mammoet

The bridge, which carries more than 100,000 vehicles daily on Interstate 376, was built beside the existing structure over several months using accelerated bridge construction techniques. The original 1951 concrete bridge was demolished by controlled implosion on 16 July 2026, with Mammoet performing the skidding installation once demolition debris was cleared.

Mammoet used 42 skid shoes spread across four primary support runs, two at the bridge piers and one at each abutment. The system, previously used to install the Chernobyl New Safe Containment structure in 2016, was selected for its low height, high load capacity and ability to resist transverse forces that can stress the lifted load. Each skid shoe could be operated independently, with an integrated hydraulic jack used to lift the bridge from its temporary construction supports and set it down on permanent bearings.

A one-inch (2.5-centimetre) tolerance was maintained from pier to abutment throughout the move. A test slide of 1.5 metres was conducted before the final 31.1-metre push to verify deflections and system behaviour.

Mammoet crew members monitor the skid shoe system during the lateral installation of the 10,000-tonne Commercial Street Bridge in Pittsburgh. Photo: Mammoet

A temporary frame was erected between the bridge and the skid shoes to guard against twisting forces, with the low shoe height giving engineers room to build the frame without widening its foundations.

Mark Lane, engineering team lead at Mammoet, said the operation marked the heaviest bridge the company has moved in the USA and noted Mammoet is already looking at further applications for the system now that it is based in the country.

The highway reopened on 3 August 2026, 17 days after closing, replacing what would have been nearly four years of intermittent lane restrictions under a conventional construction approach.

The Chernobyl connection

Photo: Mammoet

The skidding system used to move the Commercial Street Bridge was previously deployed on one of the most complex engineering projects in history. In 2016, Mammoet used the same equipment (called Novarka) to slide a 36,000-tonne protective containment structure over the remains of the Chernobyl nuclear reactor in Ukraine, encasing the destroyed reactor building. At the time, it was the largest moveable land-based structure ever built.