I-595 Bridge Jacking Report (PDF) –

This 960 ft (293 m) freeway ramp was raised by 18 in. to increase the traffic clearance for the lanes below. Raising the bridge negated having to demolish and reconstruct this ramp again, thus saving the owner much time, money and motorist inconvenience. This was a 2,600 ton lift and took approximately 30 hours to complete. The owner required that a 10% lateral capacity be maintained throughout the entire operation. This led to the development of a new and innovative lateral restraining system which performed very satisfactorily. The owner was not comfortable with a single-stroke lift, so the operation was broken down into a series of 1 in. lifts, thereby greatly increasing the total time required for this operation. A finite element model was created for the entire bridge to verify the jacking loads and to investigate the effects of differential support elevations during the lifting operation. As the pier caps had to be raised also, shoring towers were required to support the structure during reconstruction, while still maintaining the 10% lateral load capacity. CTE provided the engineering, temporary works designs and procedures to accomplish this lift, as well as jobsite technical assistance during the lift operation.

Fig. 4 – Finite Element Model