Bethlehem, PA

Hoover Mason Trestle


The 1906 Hoover Mason Trestle at the historic Bethlehem Steel plant transported raw materials on an elevated rail from the ore yard to the plant’s large furnaces. Abandoned for decades, the reinvented trestle is now the backbone of a new, half-mile-long elevated promenade offering pedestrians views into the historic steel plant, new SteelStacks, and surrounding town. SGH was the structural engineer for the meandering pedestrian walkway and access structures, including a monumental stair and exterior elevator shaft.


Although the plant kept many original and rehabilitation drawings, portions of the trestle were reconstructed or modified without documentation. SGH documented field conditions and developed adaptable steel detailing to accommodate variations in existing structural systems. We designed the new walkway structure with the following components:

  • A series of steel girders with different lengths cantilevering on either side of their post supports to accommodate the varying geometry
  • Post supports connected directly to the existing structure and rails
  • Secondary steel framing spanning between main girders and supporting concrete or steel grating walkways and cast-in-place concrete planters


SGH worked closely with the project team and completed the following:

  • Evaluated new steel and concrete structural elements to support pedestrian, seismic, wind, ice, snow, and thermal loads
  • Designed connections to accommodate thermal movements and construction tolerances
  • Designed a monumental stair, elevator, and ramp structures to provide pedestrian access to the elevated promenade
  • Developed three-dimensional models of key components and assemblies to clarify complex areas
  • Expedited shop drawing efforts by reviewing three-dimensional fabrication models prepared by the construction team

Project Summary



Completion Date


New Construction
Culture & Entertainment
Specialized Capabilities
Marine & Civil Works

Key team members