Analytical Response and Design of Buildings with Metallic Structural Fuses. I (original) (raw)

Seismic Design of Multi-story Buildings with Metallic Structural Fuses

2006

Seismic design relies on inelastic deformations through hysteretic behavior. However, this translates into damage on structural elements, permanent system deformations following an earthquake, and possibly high cost for repairs. An alternative design approach is to concentrate damage on disposable and easy to repair structural elements (i.e., “structural fuses”), while the main structure is designed to remain elastic or with minor inelastic deformations. A systematic procedure is proposed in this paper to design buildings with metallic structural fuses. The proposed procedure has been illustrated as examples of application using Buckling-restrained braces working as metallic structural fuses.

Experimental Validation of the Structural Fuse Concept

2008

Seismic design relies on inelastic deformations through hysteretic behavior. However, this translates into damage on structural elements, permanent system deformations following an earthquake, and possibly high cost for repairs. An alternative design approach is to concentrate damage on disposable and easy to repair structural elements, while the main structure is designed to remain elastic or with minor inelastic deformations. The implementation of the structural fuse concept into actual buildings would benefit from a systematic and simple design procedure. Such a general procedure is proposed in this paper for designing new or retrofitted structures. The proposed structural fuse design procedure for MDOF structures relies on results of a parametric study, considering the behavior of nonlinear SDOF systems subjected to synthetic ground motions. This procedure is illustrated as an example of application using Buckling-restrained braces (BRBs) as metallic structural fuses. To verify and validate the developed design procedure, an experimental project was conducted on the shaking table at University at Buffalo, which consists of a three-story frame designed with BRBs working as metallic structural fuses. This experimental project also assesses the replaceability of BRBs designed as sacrificeable and easy-to-repair members.

Seismic Response of Single Degree of Freedom Systems with Structural Fuses

Summary Passive energy dissipation (PED) devices have been implemented to enhance structural performance by reducing seismically induced structural damage. In this article, metallic dampers are defined to be structural fuses (SF) when they are designed such that all damage is concentrated on the PED devices, allowing the primary structure to remain elastic. Following a damaging earthquake, only the dampers would need to be replaced, making repair works easier and more expedient. Furthermore, SF introduce self-centering capabilities to the structure in that, once the ductile fuse devices have been removed, the elastic structure would return to its original position. A comprehensive parametric study is conducted, leading to the formulation of the SF concept, and allowing the identification of the possible combinations of key parameters essential to ensure adequate seismic performance for SF systems. Nonlinear time history analyses are conducted for several combinations of parameters, ...

Seismic Response of Single Degree of Freedom Structural Fuse Systems

2002

Passive energy dissipation (PED) devices have been implemented to enhance structural performance by reducing seismically induced structural damage. In this paper metallic dampers are defined to be structural fuses (SF) when they are designed such that all damage is concentrated on the PED devices, allowing the primary structure to remain elastic. Following a damaging earthquake, only the dampers would need to be replaced, making repair works easier and more expedient. Furthermore, SF introduce self-centering capabilities to the structure in that, once the ductile fuse devices have been removed, the elastic structure would return to its original position. A comprehensive parametric study is conducted leading to the formulation of the SF concept, and allowing to identify the possible combinations of key parameters essential to ensure adequate seismic performance for SF systems. Nonlinear time history analyses are conducted for several combinations of parameters, in order to cover the ...

Investigation of the Structural Fuse Concept

2005

Passive energy dissipation (PED) devices have been implemented to enhance structural performance by reducing seismically induced structural damage. In this paper metallic dampers are defined to be structural fuses (SF) when they are designed such that all damage is concentrated on the PED devices, allowing the primary structure to remain elastic. Following a damaging earthquake, only the dampers would need to be replaced, making repair works easier and more expedient. Furthermore, SF introduce self-centering capabilities to the structure in that, once the ductile fuse devices have been removed, the elastic structure would return to its original position. A comprehensive parametric study is conducted leading to the formulation of the SF concept, and allowing to identify the possible combinations of key parameters essential to ensure adequate seismic performance for SF systems. Nonlinear time history analyses are conducted for several combinations of parameters, in order to cover the range of feasible designs. The structural fuse concept can be implemented in new or existing structures using various kinds of metallic passive energy dissipating (PED) elements. This paper describes how to use metallic dampers to implement the SF concept and improve the structural behavior of systems under seismic loads. Detailed design process is presented, as well as the modifications necessary to the process for retrofitting applications.

Structural fuses and concrete-filled steel shapes for seismic and multi-hazard resistant design

Bulletin of the New Zealand Society for Earthquake Engineering, 2011

Bridges are built in a variety of locations, many of which are susceptible to multiple extreme hazards (earthquakes, vehicle collisions, tsunamis or storm surges, and blasts as a minimum for some locations). In addition, they must be built to achieve the objectives of both accelerated bridge construction (ABC) and rapid return to service following a disaster. Meeting some or all of these demands/objectives drives the development of innovative multi-hazard design concepts. This paper presents recent research on structural fuses and concrete-filled steel shapes strategies developed for this purpose. The structural fuse concept considered here for seismic resistance was developed and experimentally validated for implementation in a composite multi-column pier using double composite rectangular columns of Bi-Steel panels. Experimental results from another series of tests on the blast resistance of concrete-filled-steel-tubes support the blast resistance of the concept. In parallel, the ...

BASICS OF DYNAMICS AND EARTHQUAKE RESISTANT DESIGN

In this modern world structures are acted upon frequently by dynamic loads such as earthquake, cyclones, floods, land slides, blasting, etc., in contrast to those constructed a few centuries ago wherein loading on the structures were mainly static in nature. The speciality of static loadings are their variation in magnitudes with time do not change, i.e., their magnitudes remain constant for ever. At that time designers were happy if they designed the structures for static loading only and also found satisfied when the design fulfilled the conditions prescribed by codes of practices prevalent at that time. Subsequently extreme loadings struck the buildings and they were found wanting. When the extreme loading particularly earthquales were widespread throughout the world and their occurrences were repeated resulting in colossal loss of lives and properties, engineers and scientists became wiser and commenced organised research to find a solution to ensure safety to human beings. The outcome of this research is the formulation of texts on dynamics of structures. The present treatise is therefore entitled as Basics of Dynamics and Earthquake Resistant Structures. It covers the fundamental principles of dynamics as applicable to structures and deigns these structures to resist the forces induced by motion of the ground. As various guidelines have been framed by codal authorities of the country to design structures constructed with masonry, reinforced concrete and steel. In India the codal authority is the Bureau of Indian Standard. It has released mainly three codes related to earthquake design, viz., IS: 1890, IS: 13920 and IS: 4320 for designers to follow in their design. In essence the book contains 32 chapters dealing with various aspects of theory of vibration, basics of seismicity, lesson learnt from past earthquakes, related soil properties and its measurement, analysis techniques such as response spectrum approach and time history technique, various aspects of seismic resistance provisions of buildings, codal provisions relevant to buildings constructed in India, details about isolation and vibration control methods, mitigation of earthquake effects and finally quality aspect of materials and construction technique. The book has been prepared based on the syllabus prescribed by Anna University and other universities situated in different parts of the country. This book has been tailored to suit to design engineers and other practising engineers in their profession. The hallmark of this book is that it presents at the end of each chapter Points to Remember section which will be quite beneficial for them to score high marks in 2 marks part of the university question paper.

Engineering Structures Buckling restrained braces as structural fuses for the seismic retrofit of reinforced concrete bridge bents

2011

a b s t r a c t A structural fuse concept is proposed in which easily replaceable ductile structural steel elements are added to an RC bridge bent to increase its strength and stiffness, and also designed to sustain the seismic demand and dissipate all the seismic energy through hysteretic behavior of the fuses, while keeping the RC bridge piers elastic. While this concept could be implemented in both new and existing bridges, the focus here is on the retrofit of non-ductile reinforced concrete bridge bents. Several types of structural fuses can be used and implemented in bridges; the focus in this paper is on using Buckling Restrained Braces (BRB) for the retrofit of RC bridge bents. The results of a parametric formulation conducted introducing key parameters for the design procedure of the fuse system, validated by nonlinear time history analyses are presented. A proposed design procedure, using BRBs as metallic structural fuses, is found to be sufficiently reliable to design stru...

Dynamic analysis of buildings for earthquake-resistant design

Canadian Journal of Civil Engineering, 2003

The proposed 2005 edition of the National Building Code of Canada specifies dynamic analysis as the preferred method for computing seismic design forces and deflections, while maintaining the equivalent static force method for areas of low seismicity and for buildings with certain height limitations. Dynamic analysis procedures are categorized as either linear (elastic) dynamic analysis, consisting of the elastic modal response spectrum method or the numerical integration linear time history method, or nonlinear (inelastic) response history analysis. While both linear and nonlinear analyses require careful analytical modelling, the latter requires additional considerations for proper simulation of hysteretic response and necessitates a special study that involves detailed review of design and supporting analyses by an independent team of engineers. The paper provides an overview of dynamic analysis procedures for use in seismic design, with discussions on mathematical modelling of s...