On December the 6th 2015, during storm Desmond, substantial flooding in Cumbria resulted in the loss of the masonry arch bridge within the village of Pooley Bridge. The original bridge was erected in 1764 (itself replacing an earlier bridge from the 16th century) and was positioned at the outlet of Ullswater Lake.
Following the floods, a temporary road/footbridge was installed as an emergency measure. As part of the design and build contract for the permanent bridge replacement, Eric Wright Civil Engineering (EWCE) engaged PaSCoE to design the abutments required for a temporary pedestrian linkage across the river, including scaffold access ramps and debris protection. The temporary linkage ensured continued pedestrian access across the river allowing for the removal of the temporary bridge to enable construction of the replacement stainless steel arch bridge to commence.
The temporary linkage was founded within private land (within the flood plain) and required significant screen fencing (also by PaSCoE) to ensure the privacy of the landowners during the works. To minimise land-take, disruption for the landowners, and maintain vital working room for EWCE, the scaffold was designed to remove the need for raker props and incorporated further privacy screening.
PaSCoE were also engaged to undertake CAT III checking of the complex lifting operations required to:
· remove the emergency temporary road bridge;
· install (and remove) the temporary linkage footbridge; and,
· install the permanent stainless-steel arch bridge.
The largest lift considered by the design-check required the Sarens Gottwald AK680-3 mobile crane to lift the stainless-steel arch bridge (~300T) at a radius of 45m within a tight site, with many buried obstacles and a combination of edges retained with a stone faced concrete gravity wall and sheet piles (adjacent to the outrigger positions). Checks included analysis of primary load spreading steel mats, the working platform including edge stability / WALLAP analysis of sheet piles used to retain the granular fill, the impact of the lift on buried services and existing structures (including a ~DN1000 steel pipeline), and verification testing of the as-installed solution.
The lift of the permanent works bridge was safely completed in early May 2020.