Generation of probabilistic displacement response spectra for displacement-based design

2004 ◽  
Vol 24 (2) ◽  
pp. 149-166 ◽  
Author(s):  
Jiong Guan ◽  
Hong Hao ◽  
Yong Lu
Keyword(s):  
Response Spectra ◽  
Displacement Response ◽  
Displacement Response Spectra ◽  
Displacement Based

scholarly journals A Multi-Objective Ground Motion Selection Approach Matching the Acceleration and Displacement Response Spectra

2018 ◽  
Vol 10 (12) ◽  
pp. 4659 ◽  
Author(s):  
Yabin Chen ◽  
Longjun Xu ◽  
Xingji Zhu ◽  
Hao Liu
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Structural Response ◽  
Response Spectra ◽  
Computationally Efficient ◽  
Ground Motion Selection ◽  
Displacement Response ◽  
Rc Frames ◽  
Selection Approach ◽  
Displacement Response Spectra

For seismic resilience-based design (RBD), a selection of recorded time histories for dynamic structural analysis is usually required. In order to make individual structures and communities regain their target functions as promptly as possible, uncertainty of the structural response estimates is in great need of reduction. The ground motion (GM) selection based on a single target response spectrum, such as acceleration or displacement response spectrum, would bias structural response estimates leading significant uncertainty, even though response spectrum variance is taken into account. In addition, resilience of an individual structure is not governed by its own performance, but depends severely on the performance of other systems in the same community. Thus, evaluation of resilience of a community using records matching target spectrum at whole periods would be reasonable because the fundamental periods of systems in the community may be varied. This paper presents a GM selection approach based on a probabilistic framework to find an optimal set of records to match multiple target spectra, including acceleration and displacement response spectra. Two major steps are included in that framework. Generation of multiple sub-spectra from target displacement response spectrum for selecting sets of GMs was proposed as the first step. Likewise, the process as genetic algorithm (GA), evolvement of individuals previously generated, is the second step, rather than using crossover and mutation techniques. A novel technique improving the match between acceleration response spectra of samples and targets is proposed as the second evolvement step. It is proved computationally efficient for the proposed algorithm by comparing with two developed GM selection algorithms. Finally, the proposed algorithm is applied to select GM records according to seismic codes for analysis of four archetype reinforced concrete (RC) frames aiming to evaluate the influence of GM selection considering two design response spectra on structural responses. The implications of design response spectra especially the displacement response spectrum and GM selection algorithm are summarized.

Impact of Damping Scaling Factors on Direct Displacement-Based Design

2016 ◽  
Vol 32 (2) ◽  
pp. 843-859 ◽  
Author(s):  
Cuiyan Kong ◽  
Mervyn J. Kowalsky
Keyword(s):  
Response Spectra ◽  
Equivalent Linearization ◽  
Base Shear ◽  
Limit States ◽  
Scaling Factors ◽  
Equivalent Viscous Damping ◽  
Direct Displacement Based Design ◽  
Displacement Response Spectra ◽  
Performance Limit States ◽  
Displacement Based

Damping scaling factors (DSFs) play an important role in direct displacement-based design (DDBD) as they provide a means to establish displacement response spectra for damping values beyond 5%. Response spectra for multiple damping values are needed for DDBD as the approach relies on equivalent linearization, expressed in the form of effective stiffness and equivalent viscous damping, to establish design forces for prescribed performance limit states. In the past, DSFs based on the Eurocode have been employed for DDBD; however, recent research has resulted in more robust DSF models. This paper examines the accuracy of the current DSF equation used in DDBD across the parameters that are important for structural design. A nonlinear regression analysis is performed based on the data obtained by the Rezaeian et al. (2014) model, and a base shear adjustment factor (SAF) is proposed for application to the DDBD base shear equation.

scholarly journals Nonlinear Static and Dynamic Analysis of Rocking Masonry Corners Using Rigid Macro-Block Modeling

2019 ◽  
Vol 19 (11) ◽  
pp. 1950137 ◽  
Author(s):  
Claudia Casapulla ◽  
Linda Giresini ◽  
Luca Umberto Argiento ◽  
Alessandra Maione
Keyword(s):  
Central Italy ◽  
Response Spectra ◽  
Limit States ◽  
Static And Dynamic Analysis ◽  
Macro Block ◽  
Displacement Response Spectra ◽  
Rocking Motion ◽  
Static Approach ◽  
Nonlinear Static ◽  
Displacement Based

The corner failure is one of the most typical local mechanisms in masonry buildings vulnerable to earthquakes. The seismic assessment of this mechanism is poorly studied in the literature and in this paper it is addressed by means of both nonlinear static and dynamic analyses of rocking rigid blocks. The static approach is based on the displacement-based method and is aimed at predicting the onset of the 3D failure mechanism and its evolution through incremental kinematic analysis. This approach also considers the presence of a thrusting roof and the stabilizing contribution of frictional resistances exerted within interlocked walls. The capacity in terms of both forces and displacements is compared with the seismic demand through the construction of acceleration–displacement response spectra, with some originality. The nonlinear dynamic approach is based on the seminal Housner’s work on rocking rigid blocks and considers the influence of transverse walls, roof overloads and outward thrust, all included in an updated equation of one-sided motion. In particular, the process of defining an equivalent prismatic block, representative of the original corner geometry, is presented to convert the 3D dynamic problem into a 2D rocking motion. The wide suitability and advantage of such modeling approaches to assess the seismic response of rocking masonry structures with reference to specific limit states are demonstrated through a real case study, i.e. the collapse of a corner in a masonry school building during the 2016–2017 Central Italy seismic sequence. The compared results provide a good agreement of predictions in terms of both onset and overturning conditions, for which the static model appears to be more conservative than the dynamic one.

Static Application of Transient Hydrodynamic Loads on Vessel Internal Structures As a Result of Pulse Jet Mixer Overblow: Low-Frequency Loads

2020 ◽  
Author(s):  
Rafael Garcilazo ◽  
Brian Fant ◽  
Robert Blevins
Keyword(s):  
Waste Treatment ◽  
Low Frequency ◽  
Response Spectra ◽  
Liquid Density ◽  
Choked Flow ◽  
Internal Structures ◽  
Displacement Response Spectra ◽  
Conservation Of Momentum ◽  
Operation Results ◽  
Pulse Jet

Abstract At the Hanford Waste Treatment and Immobilization Plant (WTP), various vessels are designed to be agitated with internal pulse jet mixers (PJMs) in order to provide a means of mixing with no moving parts local to the vessel. PJMs are operated by use of an applied vacuum to draw liquid in followed by motive air to force liquid out (while not completely discharging all the liquid). This continual operation results in mixing of the vessel contents. In off-normal conditions, PJMs may completely discharge resulting in air rapidly injected into the vessel (PJM overblow). An evaluation is complete to determine the statically applied transient Rayleigh-Plesset bubble loads resulting from PJM overblow on the vessel’s internal submerged structures. The low-frequency bubble loads on internal structures is determined via analysis of overblow test data, application of the Rayleigh-Plesset equation based on bubble pressure, PJM nozzle critical flow ratios, conservation of momentum, the relative equation of motion of a submerged non-fixed structure subject to both relative drag and relative acceleration, non-flow boundary conditions, use of a displacement-response spectra, and Hooke’s Law. This theoretical Rayleigh-Plesset bubble loads model accounts for various vessel and internal submerged structure designs and different operational states: PJM cavity pressure, liquid density, depth of submerged bubble, and both choked or non-choked flow through the PJM nozzle.

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