Effects of Brace Stiffness and Nonlinearity of Viscous Dampers on Seismic Performance of Structures

2021 ◽  
pp. 2150188
Author(s):  
Siyuan Li ◽  
Yung-Tsang Chen ◽  
Y. H. Chai ◽  
Bo Li
Keyword(s):  
Seismic Performance ◽  
Structural Performance ◽  
Design Parameters ◽  
Viscous Dampers ◽  
Story Structure ◽  
Design Efficiency ◽  
Time Stepping ◽  
Seismic Hazard Mitigation ◽  
Method Effects ◽  
Supplemental Dampers

In the applications of supplemental dampers for seismic hazard mitigation, the supporting braces for the dampers are considered an important component for ensuring an efficient energy dissipation in the structure. Despite their importance, studies on the effects of the brace stiffness and the velocity exponent in the case of nonlinear viscous dampers are rather limited. In this paper, a numerical time-stepping method is developed for computing the seismic response of the structure with supporting braces and nonlinear viscous dampers. Using the proposed method, effects of the parameters of the nonlinear damper-brace systems are investigated, using first a single-story structure, followed by multi-story buildings. Results indicated that the design parameters for the dampers and supporting braces may be combined in numerous ways to satisfy a given set of structural performance objectives, but the brace stiffness can be minimized to achieve design efficiency in the range of velocity exponent commonly used for seismic applications of nonlinear viscous dampers. Results also indicated that for a set brace stiffness, if the dampers are optimally designed, the velocity exponent has an insignificant effect on the structural seismic performance objectives considered in this paper.

Innovative Use of Profiled Steel Plates for Seismic Structural Performance

2005 ◽  
Vol 8 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Y. Fukumoto ◽  
T. Takaku ◽  
T. Aoki ◽  
K. A. S. Susantha
Keyword(s):  
Numerical Analysis ◽  
Seismic Performance ◽  
Structural Design ◽  
Design Method ◽  
Steel Plates ◽  
Structural Performance ◽  
Cyclic Testing ◽  
Beam Columns ◽  
Bridge Bents ◽  
Hot Rolled

This paper presents the innovative use of hot-rolled thickness-tapered mill products, longitudinally profiled (LP) plates, for the seismic performance of bridge bents of single and portal framed piers. The study involves the inelastic cyclic testing and numerical analysis of tested beam-columns and portal frames in order to evaluate the effects of tapering ratios of LP plates, penetration of yielding, and number of locally buckled panels on their structural ductility. A structural design method is proposed for the portal frames having LP panels under cyclic loadings.

Seismic Performance of the Buckling-Restrained Brace Central Buckle for Long-Span Suspension Bridges

2018 ◽  
Vol 12 (05) ◽  
pp. 1850015 ◽  
Author(s):  
Wei Guo ◽  
Jianzhong Li ◽  
Nailiang Xiang
Keyword(s):  
Seismic Performance ◽  
Design Procedure ◽  
Suspension Bridges ◽  
Preliminary Design ◽  
Viscous Dampers ◽  
Buckling Restrained Brace ◽  
Long Span ◽  
Parametric Analyses ◽  
Yield Force ◽  
Central Buckle

In this paper, a novel central buckle composed of buckling-restrained braces (BRBs) is developed for long-span suspension bridges, and its preliminary design procedure is presented. Seismic performance of suspension bridges equipped with BRB central buckles is investigated and compared with those with conventional central buckles (e.g. rigid or flexible central buckles). Furthermore, the effect of BRB yield force, as well as the effectiveness of BRB central buckles combined with viscous dampers, is evaluated using parametric analyses. The results indicate that the BRB central buckle is more effective than other central buckles in reducing both the longitudinal girder displacements and force demands on towers during an earthquake. Furthermore, the combination of BRB central buckles and viscous dampers is a superior option for mitigating the seismic response of long-span suspension bridges.

Optimal Design of Nonlinear Viscous Dampers for Protection of Isolated Bridges

2012 ◽  
pp. 370-398
Author(s):  
Alexandros A. Taflanidis ◽  
Ioannis G. Gidaris
Keyword(s):  
Optimal Design ◽  
Dynamic Behavior ◽  
Stochastic Simulation ◽  
Seismic Risk ◽  
Probabilistic Framework ◽  
Viscous Dampers ◽  
Nonlinear Characteristics ◽  
Bridge Model ◽  
Supplemental Dampers ◽  
Isolated Bridges

A probabilistic framework based on stochastic simulation is presented in this chapter for optimal design of supplemental dampers for multi - span bridge systems supported on abutments and intermediate piers through isolation bearings. The bridge model explicitly addresses nonlinear characteristics of the isolators and the dampers, the dynamic behavior of the abutments, and the effect of pounding between the neighboring spans to each other as well as to the abutments. A probabilistic framework is used to address the various sources of structural and excitation uncertainties and characterize the seismic risk for the bridge. Stochastic simulation is utilized for evaluating this seismic risk and performing the associated optimization when selecting the most favorable damper characteristics. An illustrative example is presented that considers the design of nonlinear viscous dampers for protection of a two-span bridge.

Strengthening Research in the Longitudinal Frames of Prefabricated Structures with Viscous Dampers

2013 ◽  
Vol 671-674 ◽  
pp. 782-785
Author(s):  
Bin He ◽  
Jin Lai Pang ◽  
Cheng Qing Liu
Keyword(s):  
Seismic Performance ◽  
Pushover Analysis ◽  
Vertical Direction ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Viscous Dampers ◽  
Existing Building ◽  
Concrete Frame ◽  
Uniform Drift ◽  
Nonlinear Time History

For the lack of research in the longitudinal frame of prefabricated structure for its weak lateral stiffness, pushover analysis is conducted to evaluate the seismic performance of a fabricated concrete frame. Based on case study, the strengthening strategies with viscous dampers are analyzed. In view of the undesirable drift distribution and failure mode in the existing building, it is believed that arrangement of dampers should be designed to attain a uniform drift distribution. Based on the nonlinear time history analysis method, the strategy of damper allocation in vertical direction of the structure is investigated .Results indicate that a proper design might be attained based on the property of existing system, leading to a uniform drift distribution and better seismic performance.

Experimental Study on Performance Evaluation of an Indonesian R/C Building Damaged by the 2009 Sumatra Earthquake

2011 ◽  
Vol 82 ◽  
pp. 380-385 ◽  
Author(s):  
Yasushi Sanada ◽  
Yoshiaki Nitta ◽  
Takuya Tomonaga ◽  
Yuta Sashima
Keyword(s):  
Seismic Performance ◽  
Field Investigation ◽  
Structural Performance ◽  
Sumatra Earthquake ◽  
Test Results ◽  
Joint Failure ◽  
Structural Details ◽  
West Sumatra ◽  
Column Joint ◽  
Design Calculations

The 2009 Sumatra, Indonesia earthquake attacked Padang, which is the capital of West Sumatra province, and damaged a large number of reinforced concrete (R/C) buildings. The first author of this paper had conducted a post-earthquake field investigation in Padang. As a result, it was found that one of typical damage to buildings was beam-column joint failure. This damage was caused by poor structural details at joints, nevertheless appropriate details were provided in the Indonesian design regulation. In this study, the structural performance of a typical beam-column joint was experimentally evaluated to investigate the seismic performance of earthquake-damaged buildings. The test results revealed that joint failure occurred prior to beam/column yielding. This means that the actual seismic performance of damaged buildings was less than the design calculations in which joint failure had not been assumed.

Seismic Performance of Steel MRF Structures with Nonlinear Viscous Dampers from Real-Time Hybrid Simulations

2018 ◽  
Vol 763 ◽  
pp. 967-974 ◽  
Author(s):  
Bai Ping Dong ◽  
Richard Sause ◽  
James M. Ricles
Keyword(s):  
Real Time ◽  
Seismic Performance ◽  
Phase 1 ◽  
Base Shear ◽  
Viscous Dampers ◽  
Reduced Beam Section ◽  
Moment Resisting Frame ◽  
Moment Resisting ◽  
Two Phases ◽  
Steel Mrf

Real-time hybrid earthquake simulations (RTHS) were performed on steel moment-resisting frame (MRF) structures with nonlinear viscous dampers. The test structures for the RTHS contain a moment-resisting frame (MRF), a frame with nonlinear viscous dampers (DBF), and a gravity load system with associated seismic mass and gravity loads. The MRFs have reduced beam section beam-to-column connections and are designed for 100%, 75%, and 60%, respectively, of the base shear strength required by ASCE 7-10. RTHS were performed to evaluate the seismic performance of these MRF structures. Two phases of RTHS were conducted: (Phase-1) the DBF is the experimental substructure in the laboratory; and (Phase-2) the DBF with the MRF is the experimental substructure. Results from the two phases of RTHS are evaluated. The evaluation shows that the RTHS provide a realistic and accurate simulation of the seismic response of the test structures. The evaluation also shows that steel MRF structures designed with reduced strength and with nonlinear viscous dampers can have excellent seismic performance.

Performance Assessment of Steel Components

1987 ◽  
Vol 3 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Helmut Krawinkler
Keyword(s):  
Performance Assessment ◽  
Structural Steel ◽  
Seismic Performance ◽  
Damage Accumulation ◽  
Low Cycle Fatigue ◽  
Cumulative Damage ◽  
Structural Performance ◽  
Cycle Fatigue ◽  
Performance Parameters ◽  
Analytical Procedures

This paper presents a methodology for the assessment of cumulative damage in structural steel components subjected to cyclic inelastic loading histories of the type experienced in earthquakes. The methodology is based on low-cycle fatigue concepts and the hypothesis of linear damage accumulation. It will be shown that seismic performance of a component depends on two structural performance parameters and on the number and amplitudes of all inelastic excursions and not only on the maximum excursion. Experimental and analytical procedures for obtaining the parameters needed for a performance assessment are suggested in the paper.

Comparative seismic fragility estimates of steel moment frame buildings with or without superelastic viscous dampers

2018 ◽  
Vol 29 (18) ◽  
pp. 3598-3613 ◽  
Author(s):  
Baikuntha Silwal ◽  
Qindan Huang ◽  
Osman E Ozbulut ◽  
Mojtaba Dyanati
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Fragility Curves ◽  
Steel Frame ◽  
Structural Performance ◽  
Seismic Fragility ◽  
Viscoelastic Damper ◽  
Viscous Dampers ◽  
Earthquake Losses ◽  
Demand Models

Superelastic viscous damper is a passive hybrid control device that combines shape memory alloy cables and a viscoelastic damper to mitigate dynamic response of structures subjected to multi-level seismic hazards. In the hybrid device, shape memory alloy cables that exhibit a nonlinear but elastic response are used mainly as re-centering unit, while the viscoelastic damper composed of high-damped butyl rubber compounds is employed to augment the equivalent viscous damping provided by the device. This study evaluates the effectiveness of superelastic viscous dampers in mitigating seismic response of steel frame structures through a probabilistic framework. First, a nine-story steel frame building is designed and modeled with and without superelastic viscous dampers, and extensive nonlinear response-history analyses are conducted. Then, probabilistic demand models are developed for selected engineering demand parameters. To quantitatively compare the performance of the designed buildings, seismic fragility curves and mean annual frequency of exceeding different performance levels are developed. In particular, the structural performance is evaluated using both peak inter-story drift and residual drift responses. Results indicate that superelastic viscous dampers can significantly improve structural performance; thus, it has the potential to lower the post-earthquake losses, as the better structural performance leads to less loss in relocation, rental, and economic loss.

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