January 11, 2011
Metra, the suburban rail line in the Chicago area, honored the James McHugh Construction company with its Contractor of the Year Award.
McHugh was recognized for the reconstruction of Milwaukee District North Line Metra Bridge over Golf Road.
In May 2009, McHugh broke ground on the reconstruction of the Metra bridge over Golf Road, a two-track bridge structure that carries Metra commuter trains, Amtrak trains, as well as freight over Golf Road in Illinois.
This structure was one of the last remaining railroad bridges in the Milwaukee District that was built on timber piers and a ballasted timber deck. The original structure consisted of six deck girder spans — ballasted timber deck supported by timber bent piers.
The revised design consisted of two simply supported through girders, ballasted steel deck, and reinforced concrete abutments on caissons (a retaining, watertight structure used, for example, to work on the foundations of a bridge pier). The hallmark feature of this project was its successful rephasing resulting in an $816,000 cost savings and a five-month reduction in construction.
The original design called for a four-stage construction sequence. The staging plans called for the construction of two temporary run-around tracks, one on either side of the existing tracks. The contractor’s work between two live tracks was a major challenge with the original staging plan.
The temporary substructures necessitated the use of portions of the deteriorating existing bridge, temporary timber piles, extensive temporary sheet piling, temporary jump spans, and precast concrete box culverts oriented vertically, filled with concrete, and anchored to partially constructed new wingwalls.
This sequence would have also required four track shifts to be completed by Metra track forces.
McHugh, along with Metra’s construction manager, V3, recognized an opportunity to save Metra significant schedule time and project const by redesigning the substructures in a manner that allowed a complete rephasing and simplification of the construction sequence.
The foundation system was revised to drilled shaft supported abutments instead of driven piles. The revised staging plans included temporarily realigning both tracks to the east and utilizing the new bridge superstructure to carry the tracks over Golf Road on the temporary alignment.
This was made possible by building the east ends of the proposed abutments and supporting the steel superstructure on these partial abutments and on a single temporary drilled shaft on each side of Golf Road that was connected to the abutment end by a temporary steel roll-in girder.
Once the trains began operating on the temporary alignment, the remaining portions of the caisson-supported abutments were installed.
Then in a seven-hour work window, the entire superstructure was rolled in from its temporary location to its permanent location.