Variable friction cladding connection for seismic mitigation

Abstract

Cladding systems are conventionally designed to serve an architectural purpose and provide environmental protection for building occupants. Recent research has been conducted to enhance structural resiliency by leveraging cladding systems against man-made and natural hazards. The vast majority of the work includes the use of sacrificial cladding panels and energy dissipating connectors. These passive protection systems, though effective, have typically targeted a single hazard one-at-a-time because of their limited frequency bandwidths. A novel semi-active friction connection has been previously proposed by the authors to leverage the cladding motion for mitigating blast and wind hazards. This semi-active friction device, termed variable friction cladding connection (VFCC), is designed to laterally connect cladding elements to the structural system and dissipate energy via friction. Its variable friction force is generated onto the sliding friction plates upon which a variable normal force is applied via actuated toggles. Because of its semi-active capabilities, the VFCC could be used over wide-band excitation frequencies and is thereby, an ideal candidate for multiple hazard mitigation. The VFCC in its passive in situ mode has been previously designed to mitigate air-blast effects towards the structure and its semi-active scheme has been applied to wind hazard mitigation. In this paper, a motion-based design (MBD) procedure is developed to apply the VFCC to seismic hazard mitigation, completing its application against multiple hazards. The MBD procedure begins with the quantification of seismic load and performance objectives, and afterwards, dynamic parameters of the cladding connection are selected based on non-dimensional analytical solutions. Simulations are conducted on two example buildings to verify and demonstrate the motion-based design methodology. Results show the semi-actively controlled VFCC is capable of mitigating the seismic vibrations of structures, demonstrating the promise of the semiactive cladding system for field applications.

Numerical evaluation of a novel passive variable friction damper for vibration mitigation

“…Seismic loads are simulated using the set of six earthquake events used in [39]. The ground motion records are extracted from the PEER ground motion database.…”

Vibration Damping Performances of Buildings with Moving Façades Under Harmonic Excitation

“…On the other hand, concerning MF systems, it is desirable to endow the connection with enhanced dissipative features. Various types of devices can be conceived for this purpose and the use of high-damping or smart materials, like, for example, friction-based or Shape Memory Alloys might contribute to improve the performances of the MF systems [12,15,17].…”

“…The idea to exploit cladding displacements to improve building performances with respect to blasts and extreme seismic excitations goes back at least to [13] and led several authors to evaluate the possibility to design moving connections with relevant energy-dissipation capabilities (see, e.g., [14,15] among many others).…”

Numerical verification of variable friction cladding connection for multihazard mitigation

“…wind (Gong et al, 2019a), seismic (Gong et al, 2019b), and blast (Cao et al, 2018b). The objective of this paper is to integrate these results for multi-hazard mitigation by meeting multi-objective requirements.…”

“…The characterization of the VFCC’s friction mechanism has been conducted in a laboratory environment on a prototype (Gong et al, 2018). The authors have also developed MBD procedures and numerically demonstrated the ability of the VFCC to improve building performance under three individual hazards: wind (Gong et al, 2019a), seismic (Gong et al, 2019b), and blast (Cao et al, 2018b). The objective of this paper is to integrate these results for multihazard mitigation by meeting multiobjective requirements.…”