Direct generation of floor design spectra (FDS) from uniform hazard spectra (UHS) — Part II: extension and application of the method

2020 ◽  
Vol 47 (12) ◽  
pp. 1387-1400 ◽  
Author(s):  
Amin Asgarian ◽  
Ghyslaine McClure
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Damping Ratio ◽  
Shear Walls ◽  
Response Spectra ◽  
Companion Paper ◽  
Uniform Hazard Spectra ◽  
General Applicability ◽  
Design Spectra ◽  
Floor Acceleration

This paper extends the methodology presented in the companion paper to study the effects of non-structural components’ (NSCs) damping ratio and their location in the building on the pseudo-acceleration floor response spectra (PA-FRS) of reinforced concrete buildings, and propose equations to derive floor acceleration design spectra (FDS) directly from the uniform hazard design spectra (UHS) for Montréal, Canada. The buildings used in the study are 27 existing reinforced concrete structures with braced frames and shear walls as their lateral load resisting systems: 12 are low-rise (up to 3 stories above ground), 10 are medium-rise (4 to 7 stories), and 5 are high-rise (10 to 18 stories). Based on statistical and regression analysis of floor acceleration spectra generated from linear dynamic analysis of coupled building–NSC systems, two sets of modification factors are proposed to account for floor elevation and NSC damping, applicable to the experimentally-derived FDS for roof level and 5% NSC damping. Modification factor equations could be derived only for the low-rise and medium-rise building categories, as insufficient correlation in trends could be obtained for high-rises given their low number. The approach is illustrated in detail for two typical buildings of the database, one low-rise (Building #4) and one medium-rise (Building #18), where the proposed FDS/UHS results show agreement with those obtained from detailed dynamic analysis. The work is presented in the context of a more general methodology to show its potential general applicability to other building types and locations.

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.

Dynamic Analysis and Parameter Identification of a Single Mass Elastomeric Isolation System Using a Maxwell-Voigt Model

2006 ◽  
Vol 128 (6) ◽  
pp. 713-721 ◽  
Author(s):  
Jie Zhang ◽  
Christopher M. Richards
Keyword(s):  
Parameter Identification ◽  
Dynamic Analysis ◽  
Frequency Response ◽  
Natural Frequency ◽  
Damping Ratio ◽  
Response Spectra ◽  
Isolation System ◽  
Single Mass ◽  
Voigt Model ◽  
Stiffness And Damping

Dynamic analysis and parameter identification of a single mass elastomeric isolation system represented by a Maxwell-Voigt model is examined. Influences that the stiffness and damping values of the Maxwell element have on natural frequency, damping ratio, and frequency response are uncovered and three unique categories of Maxwell-type elements are defined. It is also shown that Voigt and Maxwell-Voigt models with equivalent natural frequencies and damping ratios can have considerably different frequency response spectra. Lastly, a parameter identification method is developed for identifying Maxwell-Voigt models from frequency response spectra. The method is based on constant natural frequency and damping ratio curves generated from modal analysis of potential Maxwell-Voigt models.

scholarly journals Seismic Fragility of Ordinary Reinforced Concrete Shear Walls with Coupling Beams Designed Using a Performance-Based Procedure

2020 ◽  
Vol 10 (12) ◽  
pp. 4075
Author(s):  
Seong-Ha Jeon ◽  
Ji-Hun Park
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Seismic Design ◽  
Nonlinear Dynamic ◽  
Shear Force ◽  
Nonlinear Dynamic Analysis ◽  
Shear Walls ◽  
Analytical Models ◽  
High Rise ◽  
Collapse Probability

The seismic performance of ordinary reinforced concrete shear walls, that are commonly used in high-rise residential buildings in Korea (h < 60 m), but are prohibited for tall buildings (h ≥ 60 m), is evaluated in this research project within the framework of collapse probability. Three bidimensional analytical models comprised of both coupled and uncoupled shear walls exceeding 60 m in height were designed using nonlinear dynamic analysis in accordance with Korean performance-based seismic design guidelines. Seismic design based on nonlinear dynamic analysis was performed using different shear force amplification factors in order to determine an appropriate factor. Then, an incremental dynamic analysis was performed to evaluate collapse fragility in accordance with the (Federal Emergency Management Agency) FEMA P695 procedure. Four engineering demand parameters including inter-story drift, plastic hinge rotation angle, concrete compressive strain and shear force were introduced to investigate the collapse probability of the designed analytical models. For all analytical models, flexural failure was the primary failure mode but shear force amplification factors played an important role in order to meet the requirement on collapse probability. High-rise ordinary reinforced concrete shear walls designed using seven pairs of ground motion components and a shear force amplification factor ≥ 1.2 were adequate to satisfy the criteria on collapse probability and the collapse margin ratio prescribed in FEMA P695.

scholarly journals EFFECTS OF SHEAR WALLS ON A TYPICAL FOUR-STORY REINFORCED CONCRETE STRUCTURE SUBJECTED TO SEVERE EARTHQUAKE EVENTS

2021 ◽  
Vol 30 (4) ◽  
pp. 779-795
Author(s):  
Nader Zad ◽  
Hani Melhem
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Concrete Structure ◽  
Time History ◽  
Shear Walls ◽  
Shear Stresses ◽  
Reinforced Concrete Structure ◽  
Beneficial Effects ◽  
Structural Resistance ◽  
Study Results

Various seismic-resistant design methods are used to ensure the stability of multi-story buildings against lateral forces caused by earthquakes. Utilization of reinforced concrete shear walls is one of the most reliable methods of design and construction of earthquake-resistant buildings because it increases structural resistance to lateral loads and stiffens and strengthens the structure, thereby minimizing earthquake-induced damages. This paper investigates the beneficial effects of using shear walls in the structural design of a typical low-rise building to improve its resistance to earthquake events. To this end, a four-story reinforced concrete structure is modeled first without shear walls, then with the addition to shear walls. The 2002 Denali Alaska earthquake is used as an example of a severe seismic excitation because it is considered the most massive strike-slip earthquake in North America in almost 150 year. SAP2000 is used to perform the dynamic analysis. In order to obtain an accurate representation of the structure’s behavior, response modal nonlinear time-history dynamic analysis is utilized to analyze and compare the response of the building with and without shear walls. Study results showed that shear walls are very effective in achieving compliance with seismic design codes. In addition, the use of shear walls significantly reduces the shear stresses, bending moments, and displacements of the various members of the structure.

Seismic Responses From Linear and Nonlinear Dynamic Analyis of RC Shear Walls

2018 ◽  
Author(s):  
Do Yeon Kim
Keyword(s):  
Numerical Model ◽  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
Damping Ratio ◽  
Shear Walls ◽  
Seismic Responses ◽  
Rc Structures ◽  
Dynamic Analyses ◽  
Linear And Nonlinear ◽  
Nonlinear Dynamic Analyses

Seismic responses from linear and nonlinear dynamic analyses of reinforced concrete (RC) shear walls are compared to see how the damping ratio and cracking behavior affect the dynamic response of the RC structures used in the nuclear power plant. The nonlinear dynamic analyses are conducted based on the numerical model which is developed to simulate the nonlinear hysteretic behavior of RC structures subjected to in-plane shear. Through comparison of the obtained numerical results with experimental data such as load-displacement relationships and response time-histories, the developed numerical model is validated. The acceleration response spectra from the nonlinear dynamic analysis results of selected RC shear wall and those from linear dynamic analysis with combinations of the damping ratio and concrete stiffness considerations according to the level of earthquake loads and the resultant stresses are addressed.

scholarly journals Seismic Performance Assessment of a Moment-Frame Reinforced Concrete Building Typology

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Marsed Leti
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Seismic Performance Assessment ◽  
Moment Frame ◽  
Limit States ◽  
Reinforced Concrete Building ◽  
Concrete Building ◽  
Building Typology

This study covers the application of Static and Dynamic nonlinear analysis to an old moment-frame reinforced concrete building. The case study selected is a template one designed in 1982 without shear walls and built throughout Albanian region in the communism era using old standards (KTP 2-78). For the capacity calculation, Pushover analysis is performed using an inverse triangular load pattern. The demand calculation is conducted using Incremental Dynamic Analysis (IDA) as a method which provides the response behavior of the structure from the elastic range until collapse. For the dynamic analysis is used a set of 18 earthquakes with no marks of directivity. Limit states are defined for both Pushover and IDA based on the FEMA 356 guidelines. The mathematical model is prepared in the environment of Zeus-NL, a software developed especially for earthquake applications. The parameters defined for the IDA analysis are 5% damped first mode spectral acceleration (Sa(T1,5%)) for the intensity measure (IM) and maximum global drift ratio (ϴmax) for the damage measure (DM). In addition, limit states are selected for the pushover curve as Immediate Occupancy (IO), Life Safety (LS) and Collapse Prevention (CP). Similarly, for the IDA curve the limit states are selected as IO, CP and Global Instability (GI) based on FEMA guidelines. Furthermore, IDA curves are summarized into 16%, 50% and 84% fractiles as suggested in the literature. Additionally, a comparison between Pushover and IDA median (50% fractile) is shown from the same graph to illustrate the correlations between performance levels. Finally, structural performance is interpreted based on the outcomes.

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