Scottish Trunk Road Network Maintenance Contract - North West Unit

Description

The focus of the Cromarty Bridge Phase 3 Refurbishment works is to minimise traffic disruption. All works above deck will be completed at night or during weekends for specific tasks. Permanent Works The refurbishment permanent works are as follows: 1. Replace bridge bearings at piers 8, 9 and 10. 2. Removal and replacement of surfacing and waterproofing local to bridge joints at piers 8, 9 and 10. Note, the existing waterproofing is bitumen based and contains Chrysotile Asbestos. 3. Excavation and installation of continuity joints on piers 8 and 9 to form a three-span continuous deck module. 4. Replace gullies adjacent to the bridge joints at piers 8, 9 and 10. 5. Replace expansion joint at pier 10. 6. Concrete repairs as required to the substructure at piers 8, 9 and 10. 7. Install Cathodic Protection system on piers 8, 9 and 10 (above and below the bridge deck). 8. Apply Pavix CCC100 or similar approved to pre-stressed beams on spans 9, 10 and 11. 9. Sever dowel bars after new bearings have been installed and the continuity slabs have achieved 85% of specified compressive strength. Temporary Works The Sub-Contractor shall include the cost of all temporary works within in the permanent works rates. As a minimum, these will include the following: 1. The topside works on the bridge deck will be completed by installing temporary bridging plates to allow traffic to flow in both directions with a 30mph speed restriction from 0600 to 1900. At night (1900 to 0600), the temporary bridging plates will be removed from a single carriageway and shuttle/convoy working Traffic Management (TM) installed to complete the topside permanent works. 2. A temporary mobile access/working platform will be installed underneath each pier to complete the permanent works underneath the bridge. The temporary platform will have to be installed prior to the hydro-demolition of the concrete bridge deck to “catch” wastewater and prevent it entering the watercourse untreated. Access to the temporary platform will be from either the western footpath or vessel adjacent to the bridge (i.e. barge, jack-up barge etc.). No plant or equipment can be stored on the bridge deck as both carriageways and the footpath will remain open during daytime hours. The works below deck are only permitted during daylight hours (0700 to 1900). 3. To replace the bridge bearings, the bridge will have to be temporarily jacked whilst the bearings are replaced. Traffic Management 1. The Sub-Contractor shall include the cost of all traffic management to ensure no full road closure within the cost of the permanent works rates. 2. The Sub-Contractor is to establish convoy or shuttle working traffic management on the carriageway at night or specified weekends as required. 3. A daytime traffic management presence will be required at all times to escort abnormal vehicles over the site location for the duration of the works. 4. Light and heavy recovery vehicles are required to be present on site for the duration of the works on the bridge deck until the topside works on the bridge deck are complete. 5. Only ad-hoc night-time traffic management will be permitted once topside works are complete. 6. Mobile VMS signs will be required at either end of the bridge to update the public with delays and progress. The VMS signs can be removed once the topside works on the bridge deck are complete. Environmental Constraints Marine Licence, CAR Licence, SEMP. Programme Timely completion of the works on the bridge deck is essential for this scheme to minimise traffic disruption. Works on the carriageway shall be completed at night or at weekends.