This study presents a novel passive metallic damper, Pipe-Fuse Damper (PFD), to improve the seismic response of structures with dissipation of the earthquake energy. The Fuse Damper (FD) was recently introduced by using steel bars as fuses, Bar-Fuse Damper (BFD), and its performance was evaluated experimentally. The Fuse Damper (FD) is built using common cross-sections found in engineering structures, such as square hollow sections (SHS) and U-shaped sections as well as metal sheets. As a special feature, the Fuse Damper (FD) uses replaceable components as an energy-absorber part with both flexural and tensile energy dissipating mechanisms. In this study, the Fuse Damper (FD) was evaluated with components of steel pipes experimentally and numerically. To assess the individual performance of this damper, the Pipe-Fuse Damper (PFD), a series of monotonic and cyclic experiments were conducted on real-scale specimens. The studied parameters for this replaceable element in the experiments were the number of pipes and their diameter, length, and thickness. The results indicate that, in addition to demonstrating a stable hysteretic behaviour and considerable energy dissipation within an appropriate displacement reversal, the proposed damper offers the easy replacement of pipe components after each failure. Moreover, the Pipe-Fuse Damper (PFD) showed less pinching effects on its hysteresis and a higher energy dissipation compared to the Bar-Fuse Damper (BFD) under the same conditions.

Introduction

Among passive control systems, metallic yield dampers are economical and do not require advanced production technologies, and they can also effectively improve seismic structural responses [1]. Moreover, these kind of dampers can be simply modelled mathematically and numerically, which is highly important in the development, design, and prediction of their behaviour. Energy dissipation in this type of damper occurs in the form of plastic deformation of the energy-absorber members through different flexural, shear, and torsional mechanisms. These dampers were first manufactured in Japan and New Zealand almost 50 years ago. In Japan, the slitted wall and the damping strips for the partition walls were employed by Muto and Guerrero in several structures to dissipate energy [2, 3]. Experimental research was conducted by Kelly and Skinner on energy absorption devices such as torsional beams, u-strips, and flexural beams in New Zealand [4, 5]. The Added Damping and Stiffness (ADAS) and the Steel Slitted Damper (SSD) are among the most popular metallic yield dampers, which have practical applications and are employed as passive control systems in a number of structures in developed countries [6, 7]. The ADAS is composed of a set of energy-absorber X-shaped or triangular steel sheets installed between the Chevron braces and its respective beam frame to dissipate the energy transferred to the structure through the flexural mechanism of the sheets. With a similar installation procedure to the ADAS, the SSD damper includes one or more slitted sheets that dissipate energy through in-plane plastic deformation and the flexural shear mechanism. These two dampers are specifically designed for Chevron braces and they cannot be installed in diagonal braces. A new damper, the Cast-Steel Yielding Brace (CSYB), performs similarly to the ADAS damper, with the exception of its constituting material which is made of cast steel, and it can be installed in diagonal braces [8]. In recent years, numerous and various innovations have been presented regarding metallic dampers by researchers, some of which are practically implemented in structures, while some of the others are still in the experimental stages [9, 10]. Since metallic dampers protect the main structural members against earthquakes by absorbing energy and directing possible destruction to their energy-absorber members, it can be claimed that they function like a fuse [11, 12]. However, this terminology mainly focuses on the protective characteristics of dampers and is less associated with the replaceable characteristic of fuses.