Aseismic Roof Isolation System Built with Steel Oval Elements: Exploratory Study

Abstract

Presented herein are the details of and results from an experimental study conducted to assess the feasibility and effectiveness of a proposed roof isolation system whose purpose is to reduce earthquake damage in buildings. The proposed isolation system entails the detachment of a building's roof from the rest of the building through the insertion of sliding bearings and the attachment of oval-shaped steel elements between the building's roof and the structure below. The objective is to form a simple resonant oscillator with a building's roof and these oval elements, with the roof providing the mass of the oscillator and the oval elements its spring and damper. An additional intention is to make the steel oval elements undergo a large number of inelastic deformation cycles and dissipate, as a result, a large portion of the energy transmitted to a building during an earthquake. The study involves the testing of a small steel frame on a shaking table alternatively with and without the proposed roof isolation system and a comparison of the story drifts and floor accelerations attained in each case. In the conducted tests, the suggested isolation technique effectively reduces the seismic response of the frame. It is concluded, thus, that the proposed roof isolation system has the potential for the development of an inexpensive and effective way to reduce earthquake damage in some buildings and merits further study.

Multi-storey structures with compound seismic isolation

“…Roof level isolation of multi-storey buildings for the reduction of storey displacements has been proposed and investigated analytically and experimentally in Villaverde [7] and Villaverde et al [8]. The detached building roof is hereby utilized as absorber mass, which is connected to the building body over isolation-damping mechanisms (elastomeric bearings with viscous or plastic hysteretic dampers).…”

Innovative Seismic Response-Controlled System with Shear Wall and Concentrated Dampers in Lower Stories

“…Nevertheless, large mass ratio TMDs have been explored mainly for earthquake inputs (Chowdhury et al, 1987;Feng and Mita, 1995;Arfiadi, 2000;Villaverde, 2000;Zhang and Iwan, 2002;Mukai et al, 2005;Villaverde et al, 2005;Tiang et al, 2008;Matta and De Stefano, 2009;Petti et al, 2010;Angelis et al, 2012;Nishii et al, 2013;Xiang and Nishitani, 2014). It should be pointed out that several projects are being planned in Japan aiming at installation of large mass pendulum systems at roof and usage of upper stories as TMD masses.…”

“…Recently, large mass ratio TMDs were tackled for base-isolated buildings (Villaverde, 2000;Villaverde et al, 2005;Angelis et al, 2012;Nishii et al, 2013;Xiang and Nishitani, 2014). While usual tall buildings exhibit large displacement near the top story because of contribution of almost uniform inter-story drifts, base-isolated buildings show relatively large displacement at the base-isolation story near ground surface.…”

Numeric Validation of 3D Printer Technology Applied to Story Isolation on Tall Buildings

“…Pan et al 1995, Pan andCui 1998 considered segmental buildings, consisting in introducing more than one interface over the height of the building. Chey et al 2013, Villaverde, 2002, Villaverde et al 2005and Ziyaeifar and Noguchi, 1998 considered applications of isolation technique on the top of existing structures by adding tuned mass damper (TMD) systems. Other researchers, such as Koh and Kobayashi, 2000, Li et al, 2002, Pochas and Pamboris, 2009, Desai Amit and Gajjar, 2012and Charmpis et al 2015 investigated story isolated structures with numerical simulations demonstrating that base isolation effectiveness reduces with superstructure flexibility.…”