FMgru SISTERS AT STUCKY MILL

Especially tough terrain, cramped space on ground, and components difficult to transport are just a few of the technical logistic features of the jobsite to restructure the Stucky Mill at Venice. Of the many macchines available, CCC chose the FMgru model 17.60 TCK crane to achieve its very ambitious objective: deliver the job on December 30, 2005.

Last April, all seven levels were lost and the eastern wall collapsed. Serious damage was also inflicted on the mill's rear tower, while a memorable fire attacked the structures of the Stucky Mill, one of Venice's best known and imposing industrial structures.

Built along the Canale della Giudecca between end last and early this century, the mill ground cereal seeds and was defined as the “most beautiful of all Italy.” After being forgotten, it was recently rediscovered by many with the start of the restructing operations that will transform it into a prestigious hotel.

The project includes recovery of the outer structure using existing walls, some 80% of which will be recovered. The project also includes total redesign of the inside parts, equivalent to some 200,000 cubic metres in volume. The job was contracted to the Bologna Building Consortium that includes the four companies of CMR, Clea Cooperative, Cefla for mechanical, heating and hydraulic plants and Gemmo for the electricìals.

At end July last, IBC visited the jobsite with its sixty operators - soon to number over 200 - to review assembly of the second crane manufactured by the Piacenza company of FMgru. The order for the first impressive 17.60 TCK tower crane with 60 metres under hook and a 60 metre jib and installed before the fire started was in fact followed by another 17.60 TCK tower crane, featuring the same jib but 46 metres operating height under hook.

THE SITE

To better understand the jobs that these cranes will be assigned to, we asked Lucio Mazzucco of Cooperativa Clea, who coordinates the operations to tell us the type of jobsite and its timing.

“It's a one-off contract job. In essence, the complete Stucky Mill hotel is to be delivered with all parts finished to the customer Acqua Marcia within December 30 2005. Given out on April 14, operations will be completion of a hotel structure consisting of 370 rooms complete with services, such as the swimming pool, the conference centre and saunas. Six drilling machines are at work today for laying over 5,000 micropiles for terrain consolidation.

This will be followed by carpentry jobs and base structure and wall restructuring. All the containment walls and structural parts such as columns and floors that are still solid and can be recovered in full safety from the historical structure will be saved. A general remark on the territorial context the jobsite is required here since we are at Venice.

Being in the midst of waters necessarily imposes rather complicated logistics. Detailed organisation of all water transport must be followed with altogether changed timing versus what would be standard for any similar jobsite that can with aid anyhow be reached with ground transport. All transports have to be synchronised and goods must get there on time since the storage space is quite restricted.”

A SPECIAL ASSEMBLY

These site features also affected the assembly dynamics of the 17.60 TCK unit with the 60 metre jib and 46 metre height under hook. The entire classical preview survey was completed by FMgru technicians, who operated in synergic cooperation with the CCC personnel and crane operators to optimise all operational logistics with stringent restrictive needs and factors such as cramped ground space, attachment based on an approach contrary to convention, as choice criteria for the mobile crane were not based on the the size of crane model to install, but the jobsite itself.

Because of soil quality, the Cooperative engineers also excluded stabilising the the crane with a base counterweight that would have sunk down due to the kg/sq-m. load conditions, and preferred using a special anchoring system with over 10 metre long anchor piles fixed in the ground. This simplified transport by not having to move the over one thousand quintals of counterweight divided into cement blocks.

Model 17.60 T was chosen in view of crane performance too, with due account taken of jobsite features. This model in fact features a 60-metre jib, lifts 1,700 kilos st the tip, 5,000 at 23 metres and is fitted with a tower complete with a system enabling it to rise up independently with a hydraulic cylinder.

In essence, the tower is assembled in a conventional fashion, that is to say one element at a time with the mobile crane. When this is no longer possible due to the limited size of the support equipment, the hydraulic system mentioned enables reaching the height required (the operation is also possible with arrow and counter arrow already on). An imposing and special unit, whose elements were brought on site by water on a goods barge capable of loading two trucks at a time loaded parallel to each other.

Also used to carry the 60-ton mobile crane, the barge was of compact enough size to tie up to the canal located on the right hand side of the Stucky Mill and let other means pass onto firm ground for unloading the components of the tower, counter arrow and all their counterweights.

The laborious transport step was followed by the delicate assembly operation of the 60-metre arrow. After tower circle and cusp assembly, the counter arrow complete with its tierods were installed so as to enable laying the first four cement counterweights, (which total ten in the operational configuration).

Given its size, as planned, the arrow was assembled and lifted to final height in two separate steps. The first part inclusive of double tierod attachments was lifted by the mobile crane that was later used to tension the tierods and add three further counterweights to predispose the structure to accept the second half of the jib. Installation at height of this latter part, also assembled on the ground, would have required crane re-positioning but the sister construction crane already assembled by FMgru was made use of at an operating height equivalent to 60 metres under hook.

After this step and laying the counterweights, rope circle was completed as well as installation of the remote supply panel on the crane base, the location of the swivel brake provided to leave the machine free to rotate without contrasting the wind when the machine is idle.

The last operation was unit inspection and setting, which consists in lifting a weight identical to maximum load to unit maximum tip load capability. Except for the hydraulic lifting system that enables raising the tower structure and the absence of the base counterweight replaced with anchor piles fixed into the ground, the 17.60 TCK has the same assembly features as other FMgru units, namely tower element assembly with four levelling bolts (two for each upright) and arrow component assembly with the extending pins that combine cut junctions at the top amd bottom alike.

On this model the Customer can opt between conventional actuation and the more progressive inverter version. Logistic complications made assembly operations last three days in all, which is twice the time normally needed in optimum conditions.

ARTICLES AND PUBLICATIONS ABOUT FMgru

NEWS AND PRESS RELEASES FROM FMgru