Zhen Hua Transit Clearance Survey

Project Description
The delivery of Halifax’s first “Post-Panamax” container crane created some unique challenges for the Halifax Port Authority (HPA). The massive crane, transported from Singapore on the Zhen Hua semi-submersible ship, would only clear the harbour bridges with a carefully planned transit. As there was no room for error, the HPA looked to Terrain Group for positioning expertise.

Services Provided
Terrain surveyors reviewed the ship, crane, and bridge dimensions prior to delivery of the crane. We also completed an analysis of tidal fluctuations, bridge loading, and predicted vessel draft. Depending on air temperature and tidal height, the crane/bridge separation could vary by as much as 20 feet.

Following the arrival of the Zhen Hua in Halifax, Terrain’s surveyors confirmed the vessel and crane dimensions. We also mounted reflectors on the underside of the Angus MacDonald and Murray MacKay suspension bridges for elevation determination by total station methods. Our calculations confirmed that under controlled conditions, a successful transit could be achieved.

On the day of transit, two teams of surveyors, located on each side of the harbour, took precise measurements of the ship/crane and the bridges. With 5,000 cheering spectators looking on, the Terrain surveyors announced the crane was “good to go” with approximately 10 feet of clearance to spare.