For the Zurich University of Applied Sciences (ZHAW), a clamping floor was erected in Test Hall 181 (Halle Max) in Winterthur to perform component tests. The approximately 1.0 m thick construction with a clamping grid of 1.50/1.50 m has floor plan dimensions of approximately 16.5 m / 9.0 m. It is equipped with 56 clamping points, which have a max. tensile force capacity of 500 kN. The floor is used for simple three- and four-point bending girder tests, where the loads are applied quasi-statically. The floor was installed in an existing industrial hall directly above the foundation soil, which is why the lower anchorage point had to be adapted compared to similar constructions in Switzerland.
Each anchorage point consists of 4 anchorage holes, into each of which 2 clamping rods can be inserted and prestressed in pairs to transmit the tensile forces. Horizontal forces are transmitted via the head plate into the clamping base by means of 2 shear sleeves inserted in pairs, which are placed accurately in the openings. The precise positioning of the shear sleeves meant that the individual clamping point constructions had to be installed very precisely, resulting in extremely small construction tolerances.
Due to the high demands on positional accuracy, the clamping construction was made in two parts. The lower part of the steel fixtures consists essentially of a base plate, 4 threaded sleeves movably positioned in steel sleeves to accommodate positional tolerances and locked against rotation, and 4 sheathing tubes. The upper part consists of the head plate, 4 cladding tube supplements and a jacket pipe which holds the cladding tube supplements and the cladding concrete.