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Wadco has fabricated friction collars in a variety of shapes, sizes and capacities. Whether round, conical, square, pyramidal, octagonal or some other shape the use of a custom friction collar may be the solution to your shoring needs.
When the penetration of an existing structure is not a viable option for whatever reason, the support of loads with the use of friction can be an effective alternative falsework approach.
The use of screwjacks to facilitate the accurate grading and controled stipping of falsework is commonly incorporated in the collar design. Since screwjacks can not be adjusted while loaded, hydraulic jacks are used during the stripping process to remove the loads from the screwjacks, enabling them to be released.
The important component associated with the use of friction collars is the necessity of "pre-loading" the bolts holding the assembly together. All bolts are torqued to the loads that will be imposed on them when the collars are loaded to their working capacity. This is necessary because each bolt will elongate when loads are imposed on the collars, thus resulting in the "loosening" of the collar. Torqueing the bolts simulates the loads that will be encountered when subsequent construction loads are applied thereby eliminating any additional elongation. Torqueing requirements are a function of the size and capacity of the collar and the number and size of the bolts being used. Values in excess of 3,000 ftlbs of torque are not uncommon.