PTS-S has reached a significant milestone at the N3/M13 Paradise Valley interchange with the successful vertical jacking of Bridge B169. This specialist operation was undertaken to increase vertical clearance for the N3 roadway below, allowing for essential infrastructure modifications.
The Challenge: Precision in a Constrained Environment
Lifting an operational bridge in a high-traffic zone requires a highly controlled approach. Our team utilised a synchronised hydraulic jacking system supported by purpose-designed temporary works. This setup allowed the bridge deck to be safely raised and secured, enabling permanent substructure modifications to proceed.
Technical Execution & Scope
The PTS-S scope included the design and implementation of the entire jacking system and the controlled lifting of the deck by a total of 680 mm.
- Custom Temporary Works: The system comprised four RC rectangular columns supporting a framed steel jacking structure around each permanent pier. These were engineered to maintain stability against wind, lateral effects, and live traffic loads throughout the process.
- High-Capacity Jacking: We deployed 250t hydraulic jacks with lock rings, providing a total lifting capacity of 2,000t at each pier. Due to tight space restrictions at the abutments, specialist "flat" hydraulic jacks were utilised.
- Disciplined Methodology: The deck was raised in meticulous 10mm increments. To ensure maximum stability, steel packers were installed after every lift cycle, transferring the load off the hydraulics and securing the deck in its raised position.
Operational Performance
Prioritising safety and structural integrity over speed, the team achieved a consistent lifting rate of 60mm to 90mm per day. This gradual approach ensured balanced load distribution and minimised differential movement across the structure.
Looking Ahead
With the lift successfully completed, the project now moves into the next phase: modifying the permanent piers and installing new bearings. Once complete, PTS-S will manage the final lowering of the bridge into its new permanent position.
This success reflects the seamless coordination between PTS-S, our design partners Struttura Consulting (Pty) Ltd, our steel fabrication partner Greenhouse Construction, and the Main Contractor.
