scholarly journals Non-Proportionality Indices and Error Constraint in Modal Analysis of Viscously Damped Linear Structures

2021 ◽  
Vol 11 (13) ◽  
pp. 6064
Author(s):  
Jorge Conde ◽  
Alejandro Bernabeu
Keyword(s):  
Viscous Damping ◽  
Practical Application ◽  
Limit Values ◽  
Acceptance Criterion ◽  
Simple Rules ◽  
Index Value ◽  
Application Limit ◽  
Error Constraint ◽  
Response Errors ◽  
Damping Systems

Use of modal procedures in systems with non-proportional damping (such as structures with added viscous damping systems) results in response errors, shown in this study to depend on dissimilar and often conflicting conditions for different variables and stories; thus, it is not possible to propose simple rules based on structural or damping properties to limit the error in a global way. However, four existing indices (originally proposed to measure damping non-proportionality) present a positive correlation with the extreme errors in modal procedures for all variables and stories. Thus, limiting the index value is a sufficient condition to keep the error in all variables within a given threshold. For practical application, limit values for these indices are tabulated as a function of error and can be used as an acceptance criterion for the validity of modal procedures.

Impact of Near-Fault Ground Motions on the Efficiency of Viscous-Damping Systems

2016 ◽  
Author(s):  
Yin-Nan Huang ◽  
Chia-Ren Liu
Keyword(s):  
Energy Dissipation ◽  
Ground Motions ◽  
Viscous Damping ◽  
Major Focus ◽  
Seismic Demands ◽  
Single Degree ◽  
Near Fault ◽  
Long Period ◽  
The Impact ◽  
Damping Systems

Energy dissipation systems can effectively reduce the seismic demands of structures and protect them from damage. However, the effectiveness of the systems is not entirely independent from the dynamic characteristics of ground motions and may be challenged by long-period velocity pulses in near-fault ground motions. The major focus of this study is to clarify the impact of the characteristics of near-fault ground motions on the effectiveness of energy dissipation systems, particularly, structures equipped with viscous dampers. A series of response-history analyses are conducted using single degree-of-systems (SDOF) with periods varying between 0.2 and 5 seconds and damping ratios between 5% and 50% and subjected to fault-normal components of 91 sets of near-fault ground motions identified in a literature prepared by Prof. Jack Baker in 2007. The effectiveness of damping in reducing seismic demands of SDOF systems subjected to near-fault motions are discussed and a model are proposed to describe their relationship.

scholarly journals PENGARUH PENAMBAHAN SERBUK BATA MERAH TERHADAP STABILITAS TANAH LEMPUNG SEBAGAI TANAH DASAR JALAN

2013 ◽  
Vol 10 (1) ◽  
Author(s):  
Moch. Sholeh ◽  
Dandung Novianto ◽  
Gerard Aponno
Keyword(s):  
Strong Support ◽  
Liquid Limit ◽  
Plasticity Index ◽  
Original Form ◽  
High Plasticity ◽  
Plastic Limit ◽  
Limit Values ◽  
Soil Mixing ◽  
Brick Powder ◽  
Index Value

Dosen Teknik Sipil Politeknik Negeri Malang Clay consists of grains - grains are very small (<0002 mm) and shows the nature - the natureof plasticity and cohesion. Cohesion indicates the fact that part - the part that is attached to eachother, while the plasticity is a trait that allows the form of the material was changed - edit withoutchanging the content or without returning to its original form, and without any cracks or brokens.And clay with high plasticity index has strong support low when used as a basic foundation of thehighway, so the need for soil improvement.From the above problems then this study aims to engineer clay with red brick powder in fourcomparisons. The first native land. Both the original soil mixed with red brick powder 5%. Thethird native soil mixed with red brick powder 7.5%. The four original soil mixed with red brickpowder 10%. Each of these sought specific gravity, liquid limit, plastic limit and plasticity index onthe original soil, mixing 5%, 7.5% and 10%. From the analysis of data obtained the followingconclusion: the original soil, the value amounting to 60.9 Liquid limit, plastic limit values of 42.8and plasticity index value of 18.1. The most optimal additional percentage is 7.5%. And PlasticityIndex value at 7.5% is 20,31.Key words : Red brick powder, Soil Stability, Subgrade and the Road.

scholarly journals Non-random vibration analysis for general viscous damping systems

2019 ◽  
Vol 32 (12) ◽  
pp. 2655-2666
Author(s):  
Chao JIANG ◽  
Long LIU ◽  
Jinwu LI ◽  
Bingyu NI
Keyword(s):  
Vibration Analysis ◽  
Random Vibration ◽  
Viscous Damping ◽  
Random Vibration Analysis ◽  
Damping Systems

scholarly journals PENGARUH PENAMBAHAN SERBUK BATA MERAH TERHADAP STABILITAS TANAH LEMPUNG SEBAGAI TANAH DASAR JALAN

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
Moch. Sholeh ◽  
Dandung Novianto
Keyword(s):  
Strong Support ◽  
Liquid Limit ◽  
Plasticity Index ◽  
Original Form ◽  
High Plasticity ◽  
Plastic Limit ◽  
Limit Values ◽  
Soil Mixing ◽  
Brick Powder ◽  
Index Value

Moch. Sholeh1 & Dandung Novianto21 & 2Fakultas Teknik Jurusan Teknik Sipil Politeknik Negeri MalangABSTRACTClay consists of grains - grains are very small (<0002 mm) and shows the nature - the natureof plasticity and cohesion. Cohesion indicates the fact that part - the part that is attached to eachother, while the plasticity is a trait that allows the form of the material was changed - edit withoutchanging the content or without returning to its original form, and without any cracks or brokens.And clay with high plasticity index has strong support low when used as a basic foundation of thehighway, so the need for soil improvement.From the above problems then this study aims to engineer clay with red brick powder in fourcomparisons. The first native land. Both the original soil mixed with red brick powder 5%. The thirdnative soil mixed with red brick powder 7.5%. The four original soil mixed with red brick powder10%. Each of these sought specific gravity, liquid limit, plastic limit and plasticity index on theoriginal soil, mixing 5%, 7.5% and 10%. From the analysis of data obtained the following conclusion:the original soil, the value amounting to 60.9 Liquid limit, plastic limit values of 42.8 and plasticityindex value of 18.1. The most optimal additional percentage is 7.5%. And Plasticity Index value at7.5% is 20,31.Key words : Red brick powder, Soil Stability, Subgrade and the Road

Performance Evaluation of Passive Damping Systems for the Seismic Retrofit of Steel Moment-Resisting Frames Subjected to Near-Field Ground Motions

2001 ◽  
Vol 17 (3) ◽  
pp. 427-456 ◽  
Author(s):  
André Filiatrault ◽  
Robert Tremblay ◽  
Assawin Wanitkorkul
Keyword(s):  
Near Field ◽  
The United States ◽  
Viscous Damping ◽  
Northridge Earthquake ◽  
Steel Moment Resisting Frames ◽  
Brittle Behavior ◽  
Moment Resisting Frames ◽  
Crustal Earthquakes ◽  
Moment Resisting ◽  
Damping Systems

Passive friction and viscous damping systems for retrofitting steel moment-resisting frames located along the west coast of the United States are considered. First, preliminary design procedures are presented for friction as well as linear and nonlinear viscous damping systems. Thereafter, nonlinear dynamic analyses are performed on a six-story moment-resisting frame designed according to seismic provisions for California prior to the 1994 Northridge earthquake. A flexural strength degradation model is considered to account for the brittle behavior of pre-Northridge welded beam-to-column connections. The structure was subjected to three different earthquake ensembles including near-field records developed for major crustal earthquakes in California. The results of a parametric study indicate that, although both friction and viscous damping systems reduce significantly the response of the structure, they are unable by themselves to prevent fracture of welded beam-to-column joints. Connection retrofit measures of the types elaborated after the Northridge earthquake would still be required.

Optimal design of passive viscous damping systems for buildings under seismic excitation

2013 ◽  
Vol 90 ◽  
pp. 253-264 ◽  
Author(s):  
Carlos A. Martínez ◽  
Oscar Curadelli ◽  
María E. Compagnoni
Keyword(s):  
Optimal Design ◽  
Seismic Excitation ◽  
Viscous Damping ◽  
Damping Systems
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