Jack-Up GSI-Elements

GSI-Type Elements

GSI-type jack-up elements consist of a cylinder-shaped housing and a spring unit. The housing is embedded in the concrete slab. The spring unit contains a helical steel spring, or set of springs. The spring units are installed after the concrete has achieved its design strength. The springs are compressed with a hydraulic jack, lifting the slab to its operating elevation. There is a some-centimetre air gap between the jacked-up slab and the substructure.

Fig. GSI-Element, principle


GSI-type spring elements are embedded in the track slab, resulting in a shallow construction height. Another advantage is the easy accessibility to the spring elements from the top. They are accessible for inspection or replacement at any time. Slab levels, especially important in tunnels, can be quickly adjusted.

Fig. Principle of a floating slab in a tunnel