Enerpac on Elvira Bridge
An Enerpac JS-750 Jack-up System has been used to replace a railway bridge weighing 500 tonne across the Cahaba River in Helena, Alabama, United States. The jack-up system allowed the new Elvira railway bridge span to be set in place while lowering the old bridge, all in one operation.
Built in 1906, the Elvira Railway Bridge’s old double-track open deck superstructure had reached the end of its useful life and was scheduled for replacement with a new single-track ballasted deck superstructure. An initial challenge of the project was the location of the bridge. The river below the bridge had a strong current in an area utilised by recreational kayakers and rafters.
With the focus on safety, the project team created a plan to build the new bridge in a specific area that would allow for efficient transport onto the old span. The approach taken was to utilise a JS-750 Jack-up System supplied by Enerpac. The old span weighed 500 tonne and was 54.9m L x 10.7m W x 13.1m H. The new span weighed 454 tonne and was 54.9m L x 5.8m W x 4.1m H. The jack-up, a multi-point hydraulic lifting system, uses an incremental stage-lifting principle. The lifting frame of each jack-up unit contains four hydraulic cylinders, one in each corner, which synchronously lift and stack steel barrels, forming lifting towers. For this application, two of the four bases of the jack-up system were set on opposite sides of the river.
Creatively, the team transported the new railway span onto the old bridge using 24 lines of Goldhofer E-Steer SPMT with 90-degree traverse movement capability to align the span with the railway track. A mat road was built across the old railway bridge so that the weight of the transporters and the new span were evenly distributed during transportation. The team designed, fabricated and provided specialized beams and transferred the weight of the new span down to slide shoes mounted on girders affixed to the jacking system to receive the weight of the new span since the old span could not support the weight of the new span and the transporters carrying it.
Using the SPMT hydraulics, the new bridge weight was transferred onto the old bridge. The jack-up system formed the four towers system supporting this double bridge setup from below. The team utilized its synchronized slide system powered by Enerpac strand jacks to side-shift both bridge spans in order to line up the new single-track railway line that replaced the old two-track line. Upon alignment, the new span was then lowered into place with Enerpac’s JS-750 jacking system while simultaneously lowering the old bridge. Lastly, the old span was additionally lowered and removed.
The replacement of the Elvira Bridge Span 2 over the river was undertaken by Burkhalter, lifting, rigging and transport professionals, following the project the assets of Burkhalter were purchased by Barnhart.