Performance-based design procedure of a novel friction-based cladding connection for blast mitigation

Abstract

Cladding systems are conventionally designed to provide buildings with environmental protection against wind, temperature, humidity, moisture, etc. Recently, researchers have proposed to leverage these systems to provide additional protection against manmade (e.g., blast) and natural (e.g., earthquakes, hurricanes) hazards. This can be achieved, for example, by redesigning the connection between the cladding and the structural system to provide energy dissipation via friction. While promising, the use of flexible cladding connection has only been considered for singular hazards. In this study, the authors propose a novel semiactive damping system to connect the cladding to the structure via a variable friction mechanism. By varying the normal force applied on friction plates through a system of adjustable toggles, it is possible to mitigate vibrations over a wide frequency range, therefore enabling mitigation of different types of hazards (i.e. to achieve multi-hazard resistance). In its passive in-situ mode, the device is designed to provide very high stiffness and friction resistance to mitigate the effects of blast.The objective of this paper is to enable a holistic integration of said device within the structural design process by developing a performance-based design procedure. The study will focus on the passive in-situ mode of the device, which will provide a stepping stone for the development of performance-based design procedures for its semi-active (i.e. actuated) capabilities. The proposed performance-based design procedure consists of the following: 1) determine the design performance criteria, including the blast properties and allowable connection gap between the cladding and structure; 2) select design properties for the cladding connection, including stiffness and damping; and 3) design a rubber impact bumper located between the structure and the cladding in order to mitigate slamming of the cladding into the structure for very high blast loads. Highlights• A novel semi-active cladding connection is demonstrated in passive mode for blast mitigation.• A 3-step performance based design (PBD) procedure is proposed for the design of this new cladding connection.• The proposed cladding connection is designed and simulated on a six-story structure exposed to blast loads.• Simulation results show that the proposed PBD procedure is acceptably conservative.• It is demonstrated that the proposed cladding connection offers significant reductions of blast-induced story displacements and accelerations. AbstractCladding systems are conventionally designed to provide buildings with environmental protection against wind, temperature, humidity, moisture, etc. Recently, researchers have proposed to leverage these systems to provide additional protection against manmade (e.g., blast) and natural (e.g., earthquakes, hurricanes) hazards. This can be achieved, for example, by redesigning the connection between the cladding and the structural system to provide energy dissipation via friction. While promising, the use...

Variable friction cladding connection for seismic mitigation

“…Variable friction has been widely studied in structural control with devices leveraging electromechanical- [49,50], electromagnetic- [51,52], magnetorheological- [53,54], hydraulic- [41,55], and piezoelectric- [56,57] based actuation. Prior work on the VFCC consisted of prototyping and characterizing the device [58], and developing an MBD methodology for blast [59] and wind [60] mitigation.…”

“…with g n (λ) = b 0 λ 2n−2 + b 1 λ 2n−4 + ... + b n−1 (58) and h n (x) = a 0 λ n + a 1 λ n−1 + ... + a n (59) its analytical solution follows [79] J = jπQ n a 0 V n (60) where j is the imaginary unit, and V n and Q n are the determinants of the following matrices 61, the analytical solution for J ci can be expressed in terms of the determinants of matrices V n and Q n using Eq. 60.…”

Motion-based design approach for a novel variable friction cladding connection used in wind hazard mitigation

“…In previous work, a prototype of the VFCC has been fabricated, experimentally tested, and its dynamic behavior characterized [28]. Afterwards, its passive application for blast energy absorption was studied and a MBD developed [29]. In this paper, the authors extend work to wind-induced vibrations.…”

“…It follows that the vast majority, if not all, of the proposed energy dissipation systems leveraging cladding systems are passive strategies. In order to further the applicability to multi-hazard mitigation, the authors have proposed a semi-active cladding connector, termed Variable Friction Cladding Connection (VFCC) [28,29]. The VFCC is a variable friction device that is engineered to laterally connect cladding elements to the structural system.…”

Performance evaluation of a semi-active cladding connection for multi-hazard mitigation

“…In previous work, a prototype of the VFCC has been fabricated and its dynamic behavior characterized 27 and a PBD approach for use in blast mitigation developed. 28 In this paper, the performance of the VFCC at mitigating wind and seismic loads is numerically evaluated on a 24-story building. The simulated loads are non-simultaneous and include two different wind hazards and six earthquakes.…”