Swiss Federal Laboratories for Materials Testing and Research

2005

Research and studies on seismic damping devices and systems started in earnest in the United States in the 1980s. In less than 15 years, damping devices moved from the university laboratory into mainstream design practice. Damping devices, damping systems, analytical tools, design procedures and codes and guidelines have been developed and deployed in building structures. The paper summarizes briefly the research work and describes in some detail the guidelines and codes of practice now available for implementing damping devices in buildings.

Journal of Civil Engineering Researchers, 2021

An earthquake is one of the most common natural phenomena, which causes a lot of human and financial losses due to the impossibility of predicting and preventing it. Iran is one of the regions with high earthquake risk in the world due to special tectonic conditions and the existence of active faults and high seismicity. New methods in earthquake engineering, especially in recent decades, have had a significant impact on reducing seismic damage to structures. Over the years, researchers have introduced a variety of methods to reduce earthquake damage to structures. However, the existence of economic issues arising from the use of innovative equipment has always been the subject of public debate. Structural control is one of the effective methods of earthquake engineering to reduce seismic response. Structural control means that the characteristics of the dynamic behavior of the structure are adjusted in such a way that the response of the structure does not exceed the allowable limits due to external stimuli. One way to control the structural behavior is to use dampers. In this research, the performance of a multi-level pipe in pipe damper and a new brace-type slit damper in structures is investigated. In this paper, first, four structural models including two 5 and 10 story models with the same plan and two 10 and 15 story models with the same plan are modeled in SAP software. Then the same structure is examined by considering the pipe damper in the pipe. The results show that the presence of this type of damper reduces the structural responses, including drift and displacement of the maximum roof to an acceptable extent. Also, according to the models, the performance of brace-type slit damper was better than multi-level pipe in pipe damper.

The effectiveness of coupling buildings through dampers to enhance their seismic performance and reduce damage was proved in past years with many numerical and experimental studies by several authors. Initially conceived for the pounding control only, this method was extended to the seismic response mitigation of adjacent buildings through their mutual connection and, more recently, connecting parts of the same structure. The analytical model used to represent this interaction problem consists of two SDOF or MDOF systems connected with dampers with different mechanical characteristics and layouts. Dampers are acknowledged as being very effective in mitigating the seismic response of existing structures. The cost effectiveness of the solution, its reliability, the chance of lowering repair costs and shortening the building downtime after an earthquake foster an opportunity for a more widespread application of this technique. Starting from an overview of the analytical problem and a critical discussion of the different studies and their main findings, the paper provides a state of the art of this seismic response control method aiming at extending the available results to the application of a novel retrofitting strategy in which the building will be connected through energy dissipation devices to specific earthquake resistant elements along the perimeter.

Structural Damping Applications in Seismic Response Modification, 2011

Rapid advances have been made during the past few decades in earthquake response modification technologies for structures, most notably in base isolation and energy dissipation systems. Many practical applications of various dampers can be found worldwide and, in the United States, damper design has been included in building codes. The current design process is simple and useful for adding supplemental damping up to a reasonable level—but it is not as useful with higher levels of damping. Taking a different approach, Structural Damping: Applications in Seismic Response Modification considers the dynamic responses of structures with added damping devices as systems governed by the combined effect of the static stiffness, period, and damping—or "dynamic stiffness"—of the structure-device system. This formulation supplies additional information for higher-level supplemental damping design that current provisions may not adequately cover. The authors also propose a more comprehensive consideration of the core issues in structural damping, which provides a useful foundation for continued research and development in seismic response modification technologies for performance-based engineering. The book includes design examples, based on the authors’ research and practical experience, to illustrate approaches that include higher-level supplemental damping to complement the use of the current NEHRP/ASCE-7 provisions. A self-contained resource on damping design principles, this book helps earthquake engineers select the most effective type of damper and determine the amount and configuration of damping under given working conditions.

Taylordevices.[Online]. Available …, 1998

Seismic Base Isolation can use elastomeric pads, sliding plates or inverted pendulums. Each method can include an energy dissipation means, but only as some kind of hysteretic damping. Hysteretic damping has limitations in terms of energy absorption and may tend to excite higher modes in some cases.. It's possible to avoid these problems with viscous dampers. Viscous damping adds energy dissipation through loads that are 90 o out of phase with bending and shear loads so even with damping levels as high as 40% of critical adverse side effects tend to be minimal. This paper presents basic theory of viscous damping, and also describes a sample project. Viscous dampers being built for the new San Bernardino Medical Center reduce both deflections and loads by 50% compared with high damping elastomer base isolation bearings by themselves.

Structural Control and Health Monitoring, 2020

International Journal of Scientific Research in Science and Technology, 2021

Dampers are significant part of structure in the highlight increment seismic opposition. As they increment the life of structure, toughness and flexiblity. In various power condition the conduct of damper assumes a significant job, which shows the need of damper .So it is important to concentrate to make its utilization in better manner.

Journal of Structural Engineering, 1996

A suggested method for design of supplemental dampers in multistory structures is presented. Active optimal control theory is adapted to design linear passive viscous or viscoelastic devices dependent on their deformation and velocity (best represented by Kelvin model). The theory using a linear quadratic regulator (LQR) is used to exemplify the procedure. The design is aimed at minimizing a performance cost function, which produces a most suitable minimal configuration of devices while maximizing their effect. The method is fully effective using full-state static feedback. Since the active feedback action require a linear combination of all states and passive devices cannot supply it, the paper introduces a methodology to eliminate the off-diagonal interactions between states using various engineering ways. The paper shows the development for velocity feedback only, for the sake of simplicity. However, the full-state formulation can be manipulated similarly to obtain a combined position-velocity feedback design. The paper shows a numerical implementation of the design methodology for a structural model prepared for further experimental considerations.