This project was the most challenging that Benchmark Scaffolding has undertaken.
The scaffolding was required to undertake blast and painting of the bridge superstructure so the scaffolding needed to fully encase the structural steel and all for full encapsulation for containment.
The bridge mast is 96m in height and leans forwards and inwards making the scaffolding design quite complex. Due to the extreme weather that occurs at the site, the project needed to be split into 2 sections, the extreme winds and very cold temperatures gave the painting contractors a very small window of opportunity to paint the bridge.
The first stage was the lower level from the ground up to 6m above the roadway (48m in height). As the bridge mast leans forward out over the water, the design needed to be progressively cantilevered as it was constructed. The base foundation at ground level was extremely steep and unstable causing significant design issues.
Benchmark Scaffolding built a heavy-duty propping base and installed cantilevered universal beams to support the cantilevered loads. The challenge with this was that they needed to build the scaffolding to full height to be able to tie it into the bridge deck structure before being able to cantilever out over the water as they had no structure to tie the scaffolding into to support the cantilevers. Because the ground condition was steep and unstable, they engaged geotechnical engineers to provide some guidance on what loads they could put into the ground and found that it was not structurally adequate to support the load of the scaffolding so they needed to design their connection (ties) into the bridge to be able to support the full weight of the scaffolding if the ground were to give way or erode under the base foundations.
The scaffolding connection to the bridge was a combination of superslim soldiers and structural beams welded and bolted in situ.
The second stage of this project (road level up to the top of the mast) is scheduled to commence in late 2022 and be completed in April 2023.