Following on from their recent success with Humber Bridge Gantries, Eadon Consulting have once again been employed as gantry designer by The Spencer Group to design gantries for the Älvsborgsbron in Gothenburg.

At just 933m long, the Älvsborgsbron is on a different scale to the Humber Bridge but presents its own particular challenges with respect to the design of the gantries.

The most noticeable difference between this and other suspension bridges is that the side spans of the bridge are viaducts therefore there are no hanger cables supporting the deck below and more importantly, not providing sideways support to the gantries in the case of storm winds.

Unlike other larger suspension bridges which Eadon Staff have worked on, which have thousands of parallel wires making up the main cable, these cables are made of eighty five, 55mm diameter locked coil wires. To make the cable section, round aluminium extrusion packs are laid longitudinally around the outside of the cable which are secured by 4mm diameter wire wrapped tightly around the full length of the cable. Careful consideration has to be given to the gantry supports bearing on the cable in order not to damage the packers.

Two gantry designs will be used on the Älvsborgsbron, one type on the main span and another on the side spans. The gantries are due to be installed in March 2011 with the main cable dehumidification project due to be completed before the winter.

Älvsborg Bridge, Sweden. Image courtesy of The Spencer Group

Älvsborg Bridge, Sweden. Image courtesy of Fluff (Wikipedia)

Solidworks image of mounted gantry

For more information regarding our movable structure design services or to discuss your access gantry requirements, please telephone 0114 399 0400 or contact us.