PSI - Issue 44

Devis Sonda et al. / Procedia Structural Integrity 44 (2023) 1188–1195 Sonda D., Pollini A.V. / Structural Integrity Procedia 00 (2022) 000 – 000

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with production processes. In addition, usually these devices are designed for higher level of forces to be used in other typologies of RC buildings or bridges. 2. Dissipative fuse Sismocell devices A cost-effective alternative to metallic systems based on steel yielding is the use of a kind of device, like dissipative fuse devices Sismocell based on carbon-wrapped steel tubes (CWST), able to add to energy dissipation other functions, in order to improve the performances of the structure in case of seismic event.

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Fig. 2. Example of installation of dissipative fuse devices Sismocell in (a) beam-column and (b) beam-roof elements connection

Main advantages of seismic protection using CWST Sismocell devices, are to assure dissipative capacity in beam column and other roof elements joints and to reduce the effects of seismic actions on the structure, concentrating damage in the devices. The behavior of the CWSTs, described in Pollini et al. (2018 and 2021), can go beyond the dissipation of energy allowing controlled displacements between structural elements. Precast RC one-storey buildings perform most part of their seismic response in terms of relative displacements between structural elements. The CWSTs, once the plastic threshold has been exceeded, allow the controlled relative displacement between structural elements. The behavior of the device, in addition to be able to respect capacity design principles, involves all parameters of dynamic structural response: elasticity, dissipation and displacement. The benefits of the introduction of CWST Sismocell devices are maximized in real existing buildings where they are able to limit the peaks of actions due to irregularities created by concentrations of stiffness due to infills or other non-structural elements. The main characteristic of the device is indeed to assure an adaptive seismic response for the structure, activating when the elastic threshold is exceeded. Once activated the device realizes a controlled decoupling between structural elements, reducing the peaks of forces on connections. Globally the structure modifies its dynamic behavior, reducing the effects of seismic action. The disconnection realized by CWST Sismocell devices, allowing a controlled relative displacement between beams and columns, has a first consequence to increase the fundamental period of the structure, with a shift towards design spectrum zones with low acceleration values. All these issues have been investigated with numerical analyses with the aim to quantify the benefits reached with the introduction of the dissipative fuse devices. 2.1. Structural behavior regularization