Terra Nova Girder Erection, Newfoundland

 

The Terra Nova Bridge is a single span, 75 m long, twin steel trapezoidal box girder bridge spanning over the Terra Nova River in Newfoundland. HEC provided construction engineering services for the steel fabricator/erector (girder launch), including the detailed design of a 50 m long steel (box truss) launching nose assembly to facilitate erection of the girders.

The innovative erection approach involved the design and utilization of a 50 m long steel box truss launching nose attached to the East end of the 75.8 m long girders. The steel box girders and launching nose assembly were incrementally assembled on the West approach of the bridge and longitudinally launched into position across the river.

Launching was facilitated with the use of concrete support foundations and lifting/roller frame assemblies on the West approach, which provided vertical and transverse support during launch and allowed for erection of the individual girder segments (completion of bolted field splices). Due to limited real estate on the beam seats, additional roller and transverse support bents were installed adjacent to the East and West abutment backwalls, supported by the abutment concrete pile caps below. Concrete ballasting was used at the East end of the steel box girders during the maximum cantilever condition (75 m) to ensure stability of the system.

HEC completed the strength and stability analysis of the parent girder (and launching nose assembly) during all launch phases, and also completed detailed designs for all required girder modifications, including: additional web stiffening, bottom flange longitudinal stiffening, bottom flange splice plate modifications, and nosing extension adaptor between launching nose and girder.

The approach eliminated the use of an expensive temporary support bent mid-span, eliminating the requirements of a temporary trestle to drive piles for the support bent, thus minimizing costs and potential impacts on the watercourse. The design also provided the client with an adjustable 50 m launching nose assembly which has proven valuable for future girder erections.

Client: Cherubini Metal Works

Value: $0.5M (Erection Only)

Year: 2012

Role: Bridge Erection Engineer