Halls Harbour Wharf

 

Harbourside Engineering Consultants (HEC), as part of a project for the Department of Public Works and Government Services Canada (PWGSC), contracted Harbourside Geotechnical Consultants (HGC) to perform geotechnical analyses and provide geotechnical recommendations in support of the Halls Harbour Wharf Reconstruction in Kings County, Nova Scotia.

Halls Harbour is located on the south shore of the Bay of Fundy, approximately 20 km northwest of Kentville. A small sluiceway spills into the harbour at the south end. The structure to be replaced consists of a timber crib and deck on the west side of the harbour which is backed by the roadway and relatively steep rock outcrops.

This work included reviewing a factual report of a geotechnical investigation prepared by another consulting firm, completing an additional geotechnical investigation comprised of one borehole, and providing geotechnical recommendations to assist with the design of the new timber crib structure. HGC worked closely with HEC to design the new crib structure which has a width of 4.88 m and a height of 6.10 m.

The initial geotechnical investigation consisted of five boreholes and an additional borehole was completed by HGC during the additional investigation. The additional work was completed because the configuration of the new wharf changed from the preliminary stages of the project. The borehole was advanced to a depth of 6.3 m using a track-mounted CME-55 diamond drill. Soils were sampled and returned to HGC’s geotechnical laboratory in Dartmouth, Nova Scotia for final classification and laboratory testing. HGC carried out field supervision of the drilling activities and managed the subcontractors required for the drilling program. The overburden at the site of the wharf structure generally comprised fill overlying a layer of loose to compact sand and gravel. Bedrock at the site comprised vesicular basalt.

HGC provided recommendations pertaining to crib backfill material requirements and design values of friction angle, total unit weight, submerged unit weight, soil/wall interface friction angle and the coefficient of active earth pressure. Recommendations were also provided for site preparation and for design of a coarse granular (rockfill) mattress.

HGC performed an analysis of crib loading to determine the resultant foundation load, the load inclination, and the load eccentricity. This information was used in bearing capacity and settlement analyses to determine the factored bearing resistance and to estimate the settlement of the new structure.

Client: HEC on behalf of Department of Public Works and Government Services Canada

Year: 2016

Role: Geotechnical Analyses and Recommendations