The enormous crane, 101 metres to the cabin and 139 metres to jib height, was taken down piece by piece.
Installed in April 2017, the Wolff luffing jib tower crane had been on site just short of two years. In that time it had been a true workhorse of construction, undertaking around 30 lifts per day or 18,400 lifts in total.
The operation to remove it required the use of the largest mobile crane available, a Llebherr LTM 1500-6.1 capable of lifting 500 tonnes and standing at 122.8 metres tall. A second mobile crane was also on site to assist with setting up the larger one, loading the vehicles, and de-rigging the Liebherr at the end.
The operation took place over three days, from Friday January 18 when Whitworth Street and the pavements around the site were closed to allow the mobile crane to set up, ready for a 7.30am start on Saturday January 19. The team worked through the day and restarted early Sunday morning. By 2pm on Sunday January 20, the tower crane had been removed and the mobile crane was de-rigging.
Over the course of the weekend 26 people were involved in ensuring the removal went smoothly, including team members from Russells, Ainscough mobile crane operators, HTC crane removal specialists, Heyrod Construction owners of the tower crane, and UPD handling traffic management.
John Millward, Russells Construction director overseeing the Axis Tower project, said: “Removal of such a large tower crane, located right in the centre of the building, is clearly a complex activity and required a great deal of planning. Add to this the constraints of such a small site and how busy this city centre location is, there was a lot of preparatory work required. We brought together a team of highly skilled operators who helped achieve the removal within the designated timeframe and with minimal disruption.
“The mobile crane is an absolutely enormous piece of equipment and the project did attract the attention of many passers-by, but the cold weather meant most just took a few snaps and went on their way. The job now is to infill the sections left void by the crane removal, make the building water tight and progress the internal fit out of the apartments.”
Undertaking more than 18,400 lifts in 22 months, the tower crane was used to lift shuttering for the in-situ concrete, steel for the reinforcement, steel for the post tensioned slabs, safe screens around the perimeter, unload waggons off the delivery road, and install around 120 of the heavier cladding panels (a smaller spider crane was used for the majority of the cladding).
Due to its proximity to the Metrolink line there was a restriction to ensure the crane could not oversail the electricity lines, to prevent any potential electrical arcing, throughout its operation and removal.
During its operation, the crane was ‘jumped’ twice, whereby it was lifted higher so match the needs of the growing building. The method of ‘jumping’ involved adding a sleeve section around the mast which lifted the cab and jib section up, leaving space for another section of mast to be slid into place below. This required incredible skill from the driver of the crane to keep it balanced, and the installation team working closely together.
Each element of the jib, counterweights and cabin were removed individually. The mobile crane took the weight of each element, then HTC removed any fixing pin that held that element in place. The mobile crane then lifted that element down to the waggons waiting within the road closure where they were loaded and returned directly to Heyrod’s yard before returning for the next section.
Once the cabin and moving parts of the crane were removed they began on the mast, the tower shape structure through the centre of the new building.
A similar process occurred whereby the mobile crane dropped its hook block above the mast, HTC then fixed it to a section of mast then the mobile took the weight.
The locating pins were then removed by HTC and the section taken away onto the back of the waiting waggon. This was repeated until all sections were removed.
Due to the mobile crane proximity to the train line and Deansgate station, consent had to be obtained from Network Rail and road closure agreement from the city council. Teams and equipment from five different companies had to be scheduled and favourable weather conditions expected, as the mobile crane cannot work in wind speeds above 20mph. All these factors came together to allow for a successful removal on January 18-20 safely, and on programme.
All works involving the crane are no longer needed and the job now starts to infill the 3mx3m hole where it once stood. The first job is to complete the roof and make the building watertight, which is set to be completed within the next couple of weeks. A 3x3m panel of concrete also needs to be cast and installed on each floor, enabling us to complete the affected apartments.
Apartments not affected by the tower crane location are already progressing well with internal fit out underway. Work is being sequenced from the lower floors upwards and has seen plaster skimming up to floor 22; kitchens, tilling and bathrooms up to floor 17; and final decoration up to floor eight. Cladding on the central section of the Whitworth Street elevation will also be installed following the removal of the hoist in April.