Infrastructure
Repair and Rehabilitation of Daly's (Shakey) Bridge
The rehabilitation of Daly’s (Shakey) bridge project has seen one of Cork’s most iconic structures faithfully restored for future generations to enjoy. The bridge provides a pedestrian route over the northern channel of the River Lee between Sunday’s Well and Fitzgerald Park in the Mardyke area of Cork City.
The suspension bridge is a well-known local landmark and its colloquial name ‘Shakey bridge’ derives from the lively movement of the deck under pedestrian loading. The bridge opened in 1927 to replace an earlier ferry crossing at the same location. It remains the only suspension bridge in Cork City and is the only surviving bridge of its type in Ireland. It's included on the Record of Protected Structures, the National Inventory of Architectural Heritage and is considered a significant contributor to the architectural heritage of the city.
Key details
Project name: Repair and Rehabilitation of Daly's (Shakey) Bridge
Client: Cork City Council
Location: Cork, Ireland
Services provided:
- Project management
- Structural engineering
- Bridge engineering
- Environmental and ecological surveys and consents
- Planning
- Feature lighting and electrical design
- Contract administration
- PSDP
- Site supervision
Challenge
The Repair and Rehabilitation of Daly’s (Shakey) bridge project was unique and complex. A special inspection in 2017 identified key structural issues including advanced corrosion and damage throughout the latticework, inadequate hanger to transverse deck beam connections and wire breakages to the existing suspension cables caused by fraying/fatigue damage. The overall structure was assigned a condition rating of 3 i.e. significant damage with repair needed very soon (within next financial year).
The project was designed and constructed within significant constraints. These included working over and adjacent to an environmentally sensitive and tidal watercourse, working in a confined urban site with limited access for plant, advanced corrosion and damage to the existing structure, presence of invasive species and intricate phasing of the works. Coupled with this through the consultation process, the public expressed a strong desire for the bridge’s signature shake to be retained.
Daly's bridge time lapse
Solution
The rehabilitation project was delivered cognisant of the principles of conservation and includes the following works:
- Phased dismantling of the latticed deck for removal off-site for grit-blasting, structural repairs and repainting
- Temporary working platforms for full encapsulation to the steel towers for grit-blasting, structural repairs and repainting in-situ
- Replacement suspension cables
- Upgrade of northern and southern approaches, including parapets, lighting, bike ramp, landscaping and surfacing
- Feature lighting of the bridge
- Restoration of original details and features, particularly where alterations to the character of the bridge have been made since 1927
We used analytical structural models and physical accelerometer measurements to record and monitor the natural frequency and vibration response of the structure prior to, and following, repair works to ensure the signature shake was retained.