Resistance of Metal Anchors on Territories Covered under Seismic Actions

Abstract

In areas affected by the threat of the substrate’s influence, in the form of its movement, it is advisable to estimate the load-bearing resistance of metal anchors by testing in areas affected under seismic actions. These tests involve determining the load resistance for pull-out metal anchors of cracked concrete. Cracked concrete can take place in cycles. In the international literature, tests are conducted on metal anchors for various classes of concrete substrates, including cycles of initiation of cracked wc = 0.10 ÷ 0.30 mm. The tests was carried out with the assumption of determining the reduction coefficient αN,seis, C1. The coefficient can lower the determined final load capacities of the fasteners to scratch out of scratched concrete substrates. Depending on the scale of the occurrence of the amplitude of the gravitational acceleration, able to cause seismic actions influences greater than 0.05 g, C1 or C2 categorization was adopted, giving European Guidelines to determine the load resistance for pull-out metal anchors from cracked concrete. In the case of a seismic action of less than 0.05 g (gravitational acceleration), it is not required to determine the ultimate lifting capacity including reduction factors for seismic activity. The occurrence of amplitude from 0.05 to 0.1 g requires testing, for initiation of scratches in concrete Δw = 0.50 mm for category C1 or Δw = 0.80 mm for category C2. In the case of interactions of amplitudes greater than 0.1 g, tests for the initiation of scratches in concrete Δw = 0.80 mm, for the regions of southern Europe and Asia are required. The article presents the results of tests for specific pull-out resistances of metal anchors installed in a cracked concrete. All tests were carried out for the purposes of this paper at normal temperature, without factoring in influence of concrete or air moisture content.