Experimental study of a new metallic damper using hourglass fuse

Articles in Press

Document Type : Article

Authors

1 civil engineering department , razi university , kermanshah, iran

2 Civil engineering department, engineering faculty, RAZI university, kermanshah, IRAN

3 razi universitycivil engineering department,.razi university. kermanshah

4 civil engineering department. azad univercity kermanshah branch

10.24200/j30.2024.63829.3289

Abstract

Being one of the world’s most earthquake-prone countries, iran has suffered thousands of live lost in earthquake throughout the past decays. Metallic yielding damper is a specific kind of passive structural control device which has shown effective behavior in past earthquakes. In this paper a new metallic yielding damper made of number of hourglass shape pins (HSP) for enhancing the seismic behavior of building structures is purposed and has been experimen-tally evaluated under monotonic and qusi-static cyclic loading. The speciments were undergo drift levels beyond the expected design ones to identify its complete behavior and all posibale failure modes. The main feature of purposed damper is replaceable hourglass shape pins (HSP) fuse. For this purpose conventional reinforcing steel bars in constructional practice have been shaped by lathe machine in the form of hourglass pins. These hourglass pins dissi-pate energy mostly through flexural and tensile mechanism when subjected to inelastic cyclic deformation and can be replaced easily in case of failure after severe earthquakes. Moreover this damper is economical, easy to install and build with no special fabrication technique. The hysteresis behavior and other important parameters of the damper such as capacity of energy dissipation, effective stiffness and equivalent damping and the effect of how the HSP is connected to its supporting plates (welding or connection by utilizing nuts) on these behav-iors has been studied through laboratory tests. Simplified analytical procedure using plastic analysis and simple rules of mechanics of solids was found to accurately predict the HSP be-havior and found to be consistent with experimental results. The experimental results indicate the bars successfully performed their function as energy absorbers and fuses in all specimens but the way HSP is connected to supporting plates can greatly affects its behavior. In the case of nut connection, a significant amount of pinching was observed in hysteresis loops which is the result of residual displacements between HSP and supporting plates and welding the bars to plates seems to solve this problem, resulting in fat and sustainable hysteresis loop without any significant strength and stiffness degradation and good energy dissipation capacity (with respect to HSP’s low weight) of the purposed damper was reached. Although both types of connections have shown acceptable behavior throughout cyclic loading, but total energy absorption capacity and equivalent viscous damping in welded connection in comparison with nut connection have been improve by 91 and 53 percent respectively.

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Sharif Journal of Civil Engineering

Articles in Press, Accepted Manuscript
Available Online from 19 March 2025

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