ROAD & BRIDGES
Casue for Celebrations - Queensferry Crossing Scotland - continued
Hoists Essential on the High Piers
On structures of such dimensions, in areas where weather conditions can be most extreme, safety considerations are of paramount importance.
Apart from the logistics involved, disruption to schedules are a serious disruption when plant and equipment fails.
So careful consideration has to be given to using the most appropriate equipment and systems that have the ruggedness to deliver optimum performance, under difficult conditions over a protracted period of time.
Delivering personnel and materials to height, over deep water is challenging. Apart from being able to deliver the productivity necessary, it must also be able to withstand high wind forces (even those these may require temporary closure of the system during the most severe conditions.)
The three high piers on the Queensferry Crossing feature six Alimak Scando 650 hoists.
Alimak Hek has provided construction access to the three concrete pylons of the new suspension bridge.
With the installation works proceeding , even in the closing stages of the project, they are continually being adapted during both the concrete construction and cable stay installation.
Alimak Hek provided three Alimak Scando 650 FC hoists with car size 1.5 m x 3.2 m and speed 54 m/min, and three Alimak Scando 650 DOL hoists with car size 1.5 m x 3.2 m and speed 38 m/min.
Each machine has been specially modified to allow a side entrance (this allows passengers to exit from the hoist car on the same side as the mast tower) onto the moving concrete formwork. Alimak Hek also designed and supplied tie installation platforms on each hoist, proving a safer working environment for the installation of ties.
Two hoists were installed on each pylon, one Alimak Scando 650 DOL serving sea level to road level and one Alimak Scando 650 FC serving road level to the top of the pylon. The pylons are over 200 meters tall.
Some of the challenges Alimak Hek overcame were designing and installing the suspended platform, on which each hoist was mounted.
The company also had to design a bespoke rolling ties to interface between the hoist and the moving concrete formwork, taking into account all the structural forces and loads of operating this equipment in extreme environments.
|To see full article|
|subscribe to PREMIUM edition|
|BUY Single Issue|