Overview

Liberty Industrial was engaged to plan and execute the demolition of a wind turbine that had suffered a significant structural failure, such that a structural collapse of the nacelle and turbine blades was a high probability - an exclusion zone of 400m was subsequently established. The project involved an unprecedented amount of planning, technical and engineering analysis, collaboration with specialists from around the world and field trials to develop and perfect the methods.

Challenges

The inability to physically approach the tower made induced collapse methodologies utilising explosives impossible.
A method was developed that used remotely operated vehicles (ROVs), drones and specifically designed cutting charges to overcome the challenges imposed by the exclusion zone.

Robust Solutions/Exceptional Outcomes

Robust solutions

The ROV utilised throughout the project was the Telerob tEODor. Typically used by the Department of Defence and police enforcement agencies, the tEODor could traverse the uneven terrain leading up to the tower and had the lifting capacity to handle a 40kg charge. Signal tests were undertaken on-site to confirm that the 400m operating range would not present a problem during the execution phase.
Throughout the planning phase, detailed engineering analysis was undertaken by De-Consult to confirm both the stability of the structure during the preparation cuts and that the structure would collapse in the intended direction given the relatively small portion of the tower that was able to be removed. Due to the vertical reach of the tEODor and the requirement of the pillar cutter charge to be less than 40kg, the design of the cutting plans and the accuracy of the oxy-cutting during execution was critical.
Vision during execution was always going to be a significant challenge. With the assistance of Omega Dev Group, 3 x DJI Matrice 300 drones with zenmuse H20T infrared cameras were utilised to provide visibility for the ROV operators. The infrared cameras were used to help mitigate one of the most significant risks for the project – fire caused by either the oxy-cutting or the detonation of the explosives. The drones were able to provide vision inside as well as around the perimeter of the tower and confirm that nothing was alight. Emergency fire control measures were also in place.

Exceptional outcomes

The collapse of the wind turbine was executed on 27th May 2021. The tower fell in the intended direction with minimal debris from the structure or the charges themselves. The project was completed within the required time frame and without incident.

Value Add

Demolition Simulation and Modelling

With exclusive license to demonstrate using Extreme Loading® for Structures (ELS) software developed by Applied Sciences International (ASI).

Deconstruction

Use of best approach demolition and dismantling such as explosive using world class fleet, safety and engineering methodologies in explosives and rigging.