Indagini teoriche e sperimentali su dissipatori ad attrito per edifici in acciaio in zona sismica

The present paper presents the results of experimental analyses carried out to study the behaviour of slotted bolted connections (SBC) as friction steel dampers. The devices consist of bolted joints with slotted holes, which can be used in both steel and RC framed structures or, alternatively, into beam-column and column-foundation joints. The most suitable configurations to increase friction are investigated utilizing steel S355J0 plates and class 10.9HV high-strength bolts, under controlled pre-load and considering different types of surface treatment. Experimental tests are carried out making use of a universal testing machine, which allows mak-ing displacement-controlled tests. Once the pre-load frictional force is reached, the plates begin to slide each other through the hollow holes, dissipating energy through friction. The paper shows the results obtained during the tests in terms of frictional force vs. displacement, friction coefficient values and variation pre-load in bolts. The results are compared with the theo-retical values derived from the calculation.