Floor response spectra for seismic design of operational and functional components of concrete buildings in Canada

2010 ◽  
Vol 37 (12) ◽  
pp. 1590-1599 ◽  
Author(s):  
M. Shooshtari ◽  
M. Saatcioglu ◽  
N. Naumoski ◽  
S. Foo
Keyword(s):  
Structural Damage ◽  
Response Spectra ◽  
Electrical Equipment ◽  
Lateral Force ◽  
Rational Approach ◽  
Concrete Buildings ◽  
Design Spectra ◽  
Floor Response Spectra ◽  
Canadian City ◽  
Functional Components

It has been observed during previous earthquakes that the damage to operational and functional components of buildings often result in more injuries, fatalities and property damage than those inflicted by structural damage. Operational and functional components of a building include architectural components, mechanical and electrical equipment, as well as building contents. A rational approach to designing these elements against seismic excitations involves the use of floor design spectra. The development of such design spectra for buildings in Canada constitutes the objective of the paper. This objective was achieved by conducting comprehensive analyses of selected reinforced concrete buildings, with different lateral force resisting systems and building heights, under code compatible earthquake records for an eastern and a western Canadian city. It was observed that the floor response was significantly amplified, especially for buildings with short periods. Generally, the higher floors showed higher amplifications with differences in spectra between the floors being more pronounced in low-rise buildings and shear wall buildings with short fundamental periods. The results provided a large volume of data to generate floor response spectra for the design of operational and functional components of buildings in Canada. The details of the approach and the design spectra are presented in the paper.

Direct generation of floor design spectra (FDS) from uniform hazard spectra (UHS) — Part I: formulation of the method

2020 ◽  
Vol 47 (12) ◽  
pp. 1372-1386 ◽  
Author(s):  
Amin Asgarian ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Three Dimensional ◽  
Response Spectra ◽  
Ambient Vibration ◽  
Uniform Hazard Spectra ◽  
Design Spectra ◽  
Floor Response Spectra ◽  
Response Amplification ◽  
Direct Generation ◽  
Ambient Vibration Measurements

In most current building codes, seismic design of non-structural components (NSCs) is addressed through empirical equations that do not capture NSC response amplification due to tuning effects with higher and torsional modes of buildings and that neglect NSC damping. This work addresses these shortcomings and proposes a practical approach to generate acceleration NSC floor design spectra (FDS) in buildings directly from their corresponding uniform hazard spectra (UHS). The study is based on the linear seismic analysis of 27 reinforced concrete buildings located in Montréal, Canada, for which ambient vibration measurements (AVM) are used to determine their in situ three-dimensional dynamic characteristics. Pseudo acceleration floor response spectra (PA-FRS) are derived at every building floor for four different NSCs damping ratios. The calculated roof FRS are compared with the 5% damped UHS and a formulation is proposed to generate roof FDS for NSCs with 5% damping directly from the UHS.

Lessons Learned from Evaluating the Responses of Instrumented Buildings in the United States: The Effects of Supporting Building Characteristics on Floor Response Spectra

2019 ◽  
Vol 35 (1) ◽  
pp. 159-191 ◽  
Author(s):  
Hamidreza Anajafi ◽  
Ricardo A. Medina
Keyword(s):  
Response Spectra ◽  
Lateral Force ◽  
The United States ◽  
Lessons Learned ◽  
Seismic Demands ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Building Models ◽  
American Society ◽  
Instrumented Buildings

Floor spectra of many instrumented buildings are evaluated to identify and quantify influential parameters on the horizontal seismic responses of acceleration-sensitive nonstructural components (NSCs). It is shown that many of these parameters are not explicitly incorporated into the American Society of Civil Engineers ASCE 7-16 design equations and are challenging to capture through numerical building models. Significant torsional responses are identified, even for nominally regular buildings, which can increase seismic demands on NSCs located at a floor periphery. For many instrumented buildings, especially single-story ones, floor diaphragms behave as flexible in their plane. This behavior, while mitigating torsional responses, can increase demands on NSCs located away from elements of the lateral-force resisting systems. An evaluation of floor acceleration responses of instrumented buildings with basements reveals that in many cases, even with the presence of perimeter concrete basement walls, accelerations at grade level could be significantly larger than those at lower basement levels. Consideration should be given to establishing the seismic base at the lowermost basement elevation.

Inclusion of Aircraft Crash into NPP Design Bases and Probabilistic Justification of Loads on Civil Structures and Equipment

2020 ◽  
pp. 35-47
Author(s):  
Nikita Chernukha
Keyword(s):  
Nuclear Power ◽  
Response Spectra ◽  
Mechanical Action ◽  
Exceedance Probability ◽  
Civil Structures ◽  
Method Of Calculation ◽  
Floor Response Spectra ◽  
Aircraft Trajectory ◽  
Probabilistic Justification ◽  
Aircraft Crash

The article is about nuclear power plant (NPP) safety analysis in case of aircraft crash. Specifically, the article considers the following problems: inclusion of aircraft crash into NPP design bases regarding calculation of frequency of an aircraft crash into NPP; aspects of justification of loads on NPP structures, systems and components (SSCs) caused by mechanical action of a primary missile – aircraft fuselage impact. Probabilistic characteristics of such random parameters as frequency of aircraft crash and direction of aircraft trajectory are determined by the results of analysis of world statistics of aviation accidents. Method of calculation of aircraft crash frequency on structures, buildings and NPP as a whole is presented. It takes into account options of accidental and intentional aircraft crashes and various aircraft approach scenarios. Procedure of probabilistic justification of loads on civil structures under aircraft impact is described. The loads are specified so as not to exceed allowable value of failure probability of NPP as a whole. Calculation of failure frequency of civil structures of existing NPP is given as an example to show analysis in case of a crash of an aircraft heavier than considered in NPP design. Procedure of probabilistic justification of dynamic loads on NPP equipment in case of aircraft impact is described. Method of floor response spectra (FRS) calculation with the required non-exceedance probability is given. Probabilistically justified loads in case of intentional aircraft impact (act of terrorism) are also considered. Additionally it is presented how internal forces calculated with the use of FRS with the required non-exceedance probability can be summed to provide analysis of subsystems.

Evaluation of floor acceleration demands from the 2017 Mexico City code seismic provisions using a continuous elastic model and records of instrumented buildings

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 213-237
Author(s):  
Miguel A Jaimes ◽  
Adrián D García-Soto
Keyword(s):  
Mexico City ◽  
Seismic Design ◽  
Soft Soil ◽  
Response Spectra ◽  
Elastic Model ◽  
Ground Acceleration ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Instrumented Buildings ◽  
Floor Acceleration

This study presents an evaluation of floor acceleration demands for the design of rigid and flexible acceleration-sensitive nonstructural components in buildings, calculated using the most recent Mexico City seismic design provisions, released in 2017. This evaluation includes two approaches: (1) a simplified continuous elastic model and (2) using recordings from 10 instrumented buildings located in Mexico City. The study found that peak floor elastic acceleration demands imposed on rigid nonstructural components into buildings situated in Mexico City might reach values of 4.8 and 6.4 times the peak ground acceleration at rock and soft sites, respectively. The peak elastic acceleration demands imposed on flexible nonstructural components in all floors, estimated using floor response spectra, might be four times larger than the maximum acceleration of the floor at the point of support of the component for buildings located in rock and soft soil. Comparison of results from the two approaches with the current seismic design provisions revealed that the peak acceleration demands and floor response spectra computed with the current 2017 Mexico City seismic design provisions are, in general, adequate.

Inelastic Analysis of Reinforced Concrete Shear Wall Structures Under Seismic Excitation

1993 ◽  
Author(s):  
Ming L. Wang
Keyword(s):  
Reinforced Concrete ◽  
Response Spectra ◽  
Shear Wall ◽  
Stiffness Degradation ◽  
Structural Stiffness ◽  
Hysteresis Model ◽  
Safety Equipment ◽  
Floor Response Spectra ◽  
Wall Structures ◽  
Degradation Models

Abstract During strong ground motions, members of reinforced concrete structures undergo cyclic deformations and experience permanent damage. Members may lose their initial stiffness as well as strength. Recently, Los Alamos National Laboratory has performed experiments on scale models of shear wall structures subjected to recorded earthquake signals. In general, the results indicated that the measured structural stiffness decreased with increased levels of excitation in the linear response region. Furthermore, a significant reduction in strength as well as in stiffness was also observed in the inelastic range. Since the in-structure floor response spectra, which are used to design and qualify safety equipment, have been based on calculated structural stiffness and frequencies, it is possible that certain safety equipment could experience greater seismic loads than specified for qualification due to stiffness reduction. In this research, a hysteresis model based on the concept of accumulated damage has been developed to account for this stiffness degradation both in the linear and inelastic ranges. Single and three degrees of freedom seismic Category I structures were analyzed and compared with equivalent linear stiffness degradation models in terms of maximum displacement responses, permanent displacement, and floor response spectra. The results indicate significant differences in responses between the hysteresis model and equivalent linear stiffness degradation models. The hysteresis model is recommended in the analysis of reinforced concrete shear-wall structures to obtain the in-structure floor response spectra for equipment qualification. Results of both cumulative and one shot tests are compared.

Dynamics of Friction Damped Braced Frames With Secondary Structures

1999 ◽  
Author(s):  
C. Adam ◽  
F. Ziegler
Keyword(s):  
Iterative Process ◽  
Numerical Procedure ◽  
Response Spectra ◽  
Secondary Structures ◽  
Structural Behavior ◽  
Light Weight ◽  
Braced Frames ◽  
Acceleration Response ◽  
Floor Response Spectra ◽  
Iterative Synthesis

Abstract The influence of light-weight secondary structures on the dynamic response of earthquake excited hysteretically damped shear frames with various elastic and inelastic substructure properties is studied numerically. The numerical procedure used in this paper is based on an iterative synthesis, where interface conditions as well as inelastic deformations are treated as additional fictitious loads and their intensities are updated in an iterative process. Acceleration response spectra of shear frames as well as floor response spectra are generated for various modal primary to secondary mass ratios. Also spectra of the standard deviation of primary and secondary accelerations are computed. Results, efficiently derived by the proposed method, are set in contrast to those derived by decoupled analyses to estimate their capability with respect to hysteretic structural behavior.

Effect of the infill panels in the floor response spectra of an 8-storey RC building

Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2476-2498
Author(s):  
André Furtado ◽  
Hugo Rodrigues ◽  
António Arêde
Keyword(s):  
Response Spectra ◽  
Floor Response Spectra ◽  
Infill Panels ◽  
Rc Building
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