Experimental investigation of the load transfer behaviour of piping supports under high-frequency excitation

This paper deals with the results of dynamic experiments performed on two typical supports with water filled pipes of nominal sizes of 4 and 12 inches subjected to an internal pressure of 10 bar. Each pipe was provided with a guide and fixed support doweled to the concrete using conical split sleeves. The set-up was excited in the two vertical planes. The required excitation was generated from the specified spectra and was applied to the concrete slabs simultaneously for both excitation planes by means of 6 hydropulse cylinders. Each series of experiments was started by applying 50% of the specified load and was increased step by step until four times the specified load was reached. The results were as follows: (a) Even at four times the specified load and having the test specimen underdesigned from the calculational point of view no break occurred. Plastic deformation in the pipe support did not occur until three times the specified load was reached and still did not affect structural integrity. (b) The actual load on the dowel approved for nuclear power plants was well above the permissible load. The calculated loads were considerably higher than the loads measured and therefore the calculation is fairly conservative. (c) No obvious local effects were recorded on the pipes and clamps. (orig.)