The design of the replacement bridge deck and approach slabs for the wet salt dump bridge required fitting into the main existing structure which was still in adequate condition not requiring to be replaced.
Scope of Work
- Structural design and documentation for fabrication of bridge deck replacement including grillage system, main deck structural frame, steel-concrete composite approach slabs.
- Fatigue assessment of the main deck welded structure.
- Preliminary lift study of approach slabs and main welded frames.
- On site consultancy during construction and installation.
Project Challenges
- Short timeframe for installation, requiring minimization of site work.
- Interface with existing structure difficult to survey.
- Fatigue governed design.
- Potential structural overstress during installation stage.
How We Managed This
- Offsite prefabrication was maximized to reduce amount of site welding.
- New structures were designed with green ends to allow adjustments following accurate survey during installation.
- Detailed 3D structural FEA under moving loads was undertaken.
- Temporary propping of the chute was designed to replace the lateral support of the deck during installation and prevent structural overstressing.
Value Engineering
- Design of the main deck in two large, welded frames, fabricated in developing markets.
- Design of adjustable interfaces to minimize installation risks.
- Presence of MAD3 Engineering (formerly McDowall Affleck) design engineer on site during the critical stages of installation.
