Greenock Crane Dismantling

Scope of Work

There was a lack of historical information for the crane, with just one available drawing that did not have any section sizes. 

The brief was to survey the crane, complete a weight take off and design a dismantling sequence and stability assessments of the crane.

During a site visit, photographs and measurements were made to provide enough information to calculate the weight take off. 

This data was then used to model the crane in 3D using BricsCAD which was used to determine centres of gravity.

This 3D model and the technical drawings were then used to create the dismantling sequence and lift weights for each component.

Site Constraints and Challenges

One key challenge was the short turnaround time required for delivery of the demolition engineering and sign off of the dismantling sequence. There was just over a month from the initial site visit to the issuing of the final design sequence.

The site was also a live container port, which ruled out other demolition methods such as pull downs or blow downs and required the planned dismantling sequence and lifts to take this into consideration.

Demolition Methodology – Crane Dismantling

A key design element was that the crane was stuck in an upright position.

The dismantling sequence was designed to take weight off the crane evenly to maintain stability.  The sequence used controlled cuts and lifts in a specific order that maintained stability at each step. 

The centre of gravity was tracked and stability re-checked after each incremental lift to ensure adequate balance was maintained in the upright position and if the center of gravity shifted outside acceptable limits, the sequence would be adjusted before proceeding further.

Project Overview

The demolition engineering and dismantling sequence was completed to meet the short timelines.

The crane was successfully dismantled over a two week period, with the dismantling taking place when the weather permitted safe lifting operations.

Additional Resources