DLT Engineering
Reference Project
Construction Equipment
Construction Engineering
Site Services
Carquinez Suspension bridge, California

Carquinez Suspension bridge was built by a joint venture between FCI-Constructors and Cleveland Bridge under a US$200m contract. DLT were responsible to the JV for carrying out all erection engineering for the steel deck, main cables and deck hangers, and were also sub-contractor for erecting the 24 No, 700 tonne steel deck units.

The deck units were fabricated in Japan and transported to site in specially converted ships, 8 deck units per shipment. The ships were able to travel to the bridge site and were moored under the main cables for lifting of the deck units into final position.

Each deck unit was lifted by 4 No 300 tonne capacity strand jacks mounted in specially designed frames connected to the top of the units. Each lift took one shift to complete. All lifting operations were controlled by a computer that monitored the load and distance travelled in each jack. Using this system it was possible to correct the jacking system during lifting to keep the deck units level and the jack loads equally balanced.

About half of the deck units could not be delivered by the ships directly under their final position due to obstructions at water level and had to be lifted up off the ship and then swung sideways, often requiring many successive swinging operations. The deck unit shown on the left was swung over 50m into final position using two sets of 4 strand jacks mounted on frames pinned to the deck to allow rotation

All 24 deck units were lifted in a period of 79 days. The below picture shows the last deck unit being lifted into final position