Safely Dismantling and Renovating the CBR2/32 Intersection Bridge
Published: 16/05/2024 13:05
In April of 2023 Richter completed the temporary works of the CBR2/32 Intersection bridge commissioned by Story Contracting which enabled the dismantling of the existing railway bridge and implementing the new bridge. Elements that had to be considered were the Dismantling Stability, Crane Pads, Protection Deck, Abutment Edge Protection, Temporary OLE Restraint within the designing process.
The design for the temporary works produced a detailed bridge dismantling sequence to enable the existing bridge to be dismantled safely. The existing bridge was lifted out in two lifts using lifting beams after removing a central section of the bridge. During the most onerous bridge lifts there had to be extra support for the cranes which included crane pads which were designed by Richter to provide this support. The engineers also needed to ensure that there was no damage to the railway infrastructure as well as enabling a safe environment for the site team which led to the development of a timber bog mat protection deck which the OLE was dropped and placed inside to prevent it from being damaged. As well as this Richter designed the temporary edge protection using scaffold and anchoring into existing masonry abutments using Hilti resin anchors. Finally, Temporary OLE restraint brackets were designed to provide lateral stability to the OLE gantries during the works using a catenary system and anchoring the brackets into the masonry using Hilti resin anchors.
Throughout the project, several risks and challenges were identified and addressed;
The poor condition of the existing bridge posed a significant challenge, with disconnected members and section loss. Careful planning, detailed analysis, and the use of additional clamping solutions were employed to ensure the safe dismantling of the bridge.
The initial crane pad locations were in close proximity to an existing manhole chamber, which raised concerns about potential surcharging. Through collaboration with the crane supplier and careful engineering, the risk of damage or instability to the manhole chamber was eliminated.
As the protection deck was designed to withstand impact loading from falling masonry, the risk of damage to the railway infrastructure at track level was mitigated. The protection deck ensured a safe working environment for the site team. The temporary OLE restraint system was implemented to protect the existing OLE gantries from potential damage due to applied tensile loads. This measure ensured the integrity and stability of the OLE system throughout the project.
To ensure the stability and safety of the dismantling process, finite element analysis was employed to model the existing bridge structure in 3D using STAAD software. The analysis enabled the identification of necessary measures, such as Dywidag bars and Lindapter clamps, to enhance the temporary stability of the bridge during lifting.
Through collaboration, meticulous planning, and the application of engineering expertise, Richter successfully designed and implemented the temporary works solutions required for the CBR2/32 Intersection Bridge project in Sutton Coldfield. The careful consideration of risks, challenges, and innovative solutions contributed to the project's overall success and timely completion.