A study on the improvement of seismic coefficients for pseudo static analysis of gravity type quay wall via dynamic centrifuge tests

Mapping Intimacies ◽

10.5194/egusphere-egu2020-4356 ◽

2020 ◽

Author(s):

Moon-Gyo Lee ◽

Hyung-Ik Cho ◽

Chang-Guk Sun ◽

Han-Saem Kim

Keyword(s):

Dynamic Behavior ◽

Seismic Analysis ◽

Inertial Force ◽

Gravitational Acceleration ◽

Ground Acceleration ◽

Natural Period ◽

The Real ◽

Analysis And Design ◽

Centrifuge Tests ◽

Quay Wall

The pseudo-static approach has been conventionally applied for the design of gravity type quay walls. In this method, the seismic coefficient (kh), expressed in terms of acceleration due to gravity, is used to convert the real dynamic behavior to an equivalent pseudo-static inertial force for seismic analysis and design. The existing kh&#160;is simply defined as the expected peak ground acceleration (PGA) of the ground divided by the gravitational acceleration (g), which does not sufficiently reflect the real dynamic behavior. In order to improve the kh&#160;definition, a number of studies have been performed for reducing the differences between pseudo-static and true dynamic behavior. In this regard, questions regarding the need for considering the effect of frequency characteristics of input earthquake, natural period of the backfill soil and the subsoil underneath the wall, and wall height on the deformation of quay wall crown (Dh) have been explored. In this study, dynamic centrifuge tests were conducted using the gravity type quay wall models designed with a kh value of 0.13 to assess the behavior of the model wall during earthquakes. Three different variables: input earthquake motions, wall heights and the thickness of subsoil underneath the wall were considered, and the test results were compared and analyzed to assess the validity of the conventional kh concept under these conditions. In addition, some improvements that should be considered for the future revision of the kh&#160;definition are discussed.

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Seismic Analysis of Typical Cut-and-Cover Subway Stations in Beijing

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.90-93.2200 ◽

2011 ◽

Vol 90-93 ◽

pp. 2200-2206

Author(s):

Jing Bo Liu ◽

Dong Dong Zhao ◽

Wen Hui Wang

Keyword(s):

Peak Ground Acceleration ◽

Seismic Analysis ◽

Relative Displacement ◽

High Ratio ◽

Underground Structures ◽

Ground Acceleration ◽

Analysis And Design ◽

Side Walls ◽

Subway Stations ◽

Lower Ratio

To obtain the seismic responses of typical subway stations in Beijing, a nonlinear analysis was conducted using a pushover method for seismic analysis and design of underground structures. The analysis mainly focuses on stress in columns and side walls and relative displacement between top and bottom slabs under 3 different levels of PGA (peak ground acceleration). From the analysis, the column shows good ductility due to its high ratio of reinforcement, and it has a good performance under strong motions. Compared with columns, side walls suffer from brittle failure and lose bearing capacity prior to column for its lower ratio of reinforcement. The calculated displacement indicates that the relative displacement between top and bottom slabs is linear proportional to peak ground relative displacement (PGRD). And compared with peak ground acceleration (PGA), PGRD is a more reliable design parameter of ground motion for underground structures. And the typical subway stations in Beijng can withstand the earthquake with design PGA up to 0.2 g.

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Development of a new method for assessing otolith function in mice using three-dimensional binocular analysis of the otolith-ocular reflex

Scientific Reports ◽

10.1038/s41598-021-96596-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shotaro Harada ◽

Takao Imai ◽

Yasumitsu Takimoto ◽

Yumi Ohta ◽

Takashi Sato ◽

...

Keyword(s):

Eye Movement ◽

Three Dimensional ◽

Vertical Component ◽

Inertial Force ◽

Linear Acceleration ◽

The Body ◽

Body Axis ◽

Gravitational Acceleration ◽

Ocular Reflex ◽

Translational Movement

AbstractIn the interaural direction, translational linear acceleration is loaded during lateral translational movement and gravitational acceleration is loaded during lateral tilting movement. These two types of acceleration induce eye movements via two kinds of otolith-ocular reflexes to compensate for movement and maintain clear vision: horizontal eye movement during translational movement, and torsional eye movement (torsion) during tilting movement. Although the two types of acceleration cannot be discriminated, the two otolith-ocular reflexes can distinguish them effectively. In the current study, we tested whether lateral-eyed mice exhibit both of these otolith-ocular reflexes. In addition, we propose a new index for assessing the otolith-ocular reflex in mice. During lateral translational movement, mice did not show appropriate horizontal eye movement, but exhibited unnecessary vertical torsion-like eye movement that compensated for the angle between the body axis and gravito-inertial acceleration (GIA; i.e., the sum of gravity and inertial force due to movement) by interpreting GIA as gravity. Using the new index (amplitude of vertical component of eye movement)/(angle between body axis and GIA), the mouse otolith-ocular reflex can be assessed without determining whether the otolith-ocular reflex is induced during translational movement or during tilting movement.

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Seismic Analysis and Design of Pile Group Bridge Foundations in Soft and Liquefied Soil

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2202-22 ◽

2010 ◽

Vol 2202 (1) ◽

pp. 183-191

Author(s):

Amir M. Malek ◽

Mohammed S. Islam

Keyword(s):

Seismic Analysis ◽

Pile Group ◽

Bridge Foundations ◽

Analysis And Design

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Implementing the performance-based seismic design for new reinforced concrete structures: Comparison among ASCE/SEI 41, TBI, and LATBSDC

Earthquake Spectra ◽

10.1177/8755293020981968 ◽

2021 ◽

pp. 875529302098196

Author(s):

Siamak Sattar ◽

Anne Hulsey ◽

Garrett Hagen ◽

Farzad Naeim ◽

Steven McCabe

Keyword(s):

Reinforced Concrete ◽

Los Angeles ◽

Seismic Design ◽

Common Ground ◽

Seismic Analysis ◽

Tall Buildings ◽

The United States ◽

Analysis And Design ◽

Performance Based Seismic Design ◽

New Buildings

Performance-based seismic design (PBSD) has been recognized as a framework for designing new buildings in the United States in recent years. Various guidelines and standards have been developed to codify and document the implementation of PBSD, including “ Seismic Evaluation and Retrofit of Existing Buildings” (ASCE 41-17), the Tall Buildings Initiative’s Guidelines for Performance-Based Seismic Design of Tall Buildings (TBI Guidelines), and the Los Angeles Tall Buildings Structural Design Council’s An Alternative Procedure for Seismic Analysis and Design of Tall Buildings Located in the Los Angeles Region (LATBSDC Procedure). The main goal of these documents is to regularize the implementation of PBSD for practicing engineers. These documents were developed independently with experts from varying backgrounds and organizations and consequently have differences in several degrees from basic intent to the details of the implementation. As the main objective of PBSD is to ensure a specified building performance, these documents would be expected to provide similar recommendations for achieving a given performance objective for new buildings. This article provides a detailed comparison among each document’s implementation of PBSD for reinforced concrete buildings, with the goal of highlighting the differences among these documents and identifying provisions in which the designed building may achieve varied performance depending on the chosen standard/guideline. This comparison can help committees developing these documents to be aware of their differences, investigate the sources of their divergence, and bring these documents closer to common ground in future cycles.

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