Springhill Junction Bridge Demolition, Springhill, NS

 

The Springhill Junction Bridge was a 38 m single span through truss bridge built in 1936. The existing bridge had reached its service life due to corrosion and was replaced by a new two span steel plate girder bridge adjacent to the existing bridge.

The existing steel through truss bridge was located over a busy railway line which could not be closed during demolition. An innovative design was therefore required to demolish the bridge without interfering with railway traffic. HEC design a demolition method which allowed the existing bridge to be cut in to sections and each section could then be lifted by crane on an existing gravel roadway parallel to the railway tracks.

Sections of barge, that the contractor owned, were used as a temporary tower to support the structure near mid-span. This along with temporary support steel allowed the existing bridge to be cut in two sections and remain stable.  Pad-eyes where welded to each section of the bridge and a crane was used to lift and lower each section of the bridge. This was complicated by the tight site which made positioning the crane and demolished section of bridge difficult.

The scope of work included the full analysis of the existing structure during demolition to ensure it was adequate once it was cut in two sections and during lifting, design of the pad-eyes, rigging, spreader beam, selection and positioning of the crane, design of temporary support steel and analysis of barge sections for imposed loads. The project was a success and was completed on time, on budget and without a closure of the railway.

Client: Dexter Construction

Value: $0.5 M (Approximate)

Year: 2012

Role: Lead Engineer