Comparative study on the effect of outrigger on seismic response of tall buildings with braced and Wall Core. II: Determining seismic design parameters

2021 ◽  
Author(s):  
Maysam Samadi ◽  
Norouz Jahan
Keyword(s):  
Comparative Study ◽  
Seismic Response ◽  
Seismic Design ◽  
Tall Buildings ◽  
Design Parameters

scholarly journals Seismic Response Characteristics of Stabilizing Pile Based on Elastic-Plastic Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Honglue Qu ◽  
Ying Liu ◽  
Hao Luo ◽  
Huanguo Hu ◽  
Qindi Hu
Keyword(s):  
Plastic Zone ◽  
Seismic Response ◽  
Ground Motion ◽  
Seismic Design ◽  
Design Parameters ◽  
Plastic State ◽  
Elastic Plastic ◽  
Stabilizing Pile ◽  
Response Characteristics ◽  
Plastic Analysis

Stabilizing pile is widely used in the landslide controlling projects and shows excellent seismic performance under the action of earthquake. Therefore, in order to improve seismic design theory, it is of importance to study the seismic response characteristics of stabilizing pile based on elastic-plastic analysis. In view of this, elastic-plastic constitutive model was established to deduce the plastic zone of stabilizing pile. Based on elastic-plastic analysis, the seismic response characteristics and the influence of different section sizes, material strengths, and peak ground motion acceleration (PGA) were analyzed by ANSYS 3D. Resultantly, the elastic-plastic fourth-order tensor Cijklep was deduced, which can be used to calculate plastic strain of stabilizing pile under loading. Compared with Chinese code, the material of stabilizing pile working with elastic-plastic state will be decreased under the same section size and the same property. Furthermore, stabilizing pile is in the elastic stage at the beginning under the action of earthquake. With the increase of ground motion time, the section starts to exhibit elastic-plastic state and then the plastic zone expands gradually. Finally, the plastic zone runs through the whole section, resulting in the performance loss of the pile. In addition, under the different design parameters, pile shows different seismic response characteristics; namely, changing these parameters reasonably can improve the seismic design.

A Comparative Study of U.S.-Japan Seismic Design of Highway Bridges: I. Design Methods

2003 ◽  
Vol 19 (4) ◽  
pp. 913-932 ◽  
Author(s):  
W. P. Yen ◽  
J. D. Cooper ◽  
S. W. Park ◽  
S. Unjoh ◽  
T. Terayama ◽  
...  
Keyword(s):  
Comparative Study ◽  
Seismic Design ◽  
Highway Bridges ◽  
The United States ◽  
Companion Paper ◽  
Public Works ◽  
Design Parameters ◽  
Shake Table ◽  
Reinforced Concrete Column ◽  
Design Specifications

This paper summarizes the results of a comparative study on seismic design of highway bridges jointly undertaken by the U.S. Federal Highway Administration and Japan's Public Works Research Institute. The seismic design specifications for highway bridges of the two countries are reviewed and compared with respect to their design philosophies and procedures. Some major design parameters including design seismic forces, response modification factors and minimum support lengths are addressed in detail. The differences between the two specifications are illustrated via a design example of a reinforced concrete column for simple, two-span bridges common in both countries. Three different scale models of the column are designed in accordance with the seismic design specifications of the United States and Japan, and tested on a shake table for their comparative seismic performance. The results of the shake table tests are discussed separately in a companion paper.

scholarly journals Probabilistic seismic response analysis of coastal highway bridges under scour and liquefaction conditions: does the hydrodynamic effect matter?

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Yutao Pang ◽  
Aijun Ye
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Highway Bridges ◽  
Element Model ◽  
Response Analysis ◽  
Hydrodynamic Effect ◽  
Strong Earthquakes ◽  
Influence Of Water ◽  
Scour Hazard ◽  
Ground Motion Records

AbstractCoastal highway bridges are usually supported by pile foundations that are submerged in water and embedded into saturated soils. Such sites have been reported susceptible to scour hazard and probably liquefied under strong earthquakes. Existing studies on seismic response analyses of such bridges often ignore the influence of water-induced hydrodynamic effect. This study assesses quantitative impacts of the hydrodynamic effect on seismic responses of coastal highway bridges under scour and liquefaction potential in a probabilistic manner. A coupled soil-bridge finite element model that represents typical coastal highway bridges is excited by two sets of ground motion records that represent two seismic design levels (i.e., low versus high in terms of 10%-50 years versus 2%-50 years). Modeled by the added mass method, the hydrodynamic effect on responses of bridge key components including the bearing deformation, column curvature, and pile curvature is systematically quantified for scenarios with and without liquefaction across different scour depths. It is found that the influence of hydrodynamic effect becomes more noticeable with the increase of scour depths. Nevertheless, it has minor influence on the bearing deformation and column curvature (i.e., percentage changes of the responses are within 5%), regardless of the liquefiable or nonliquefiable scenario under the low or high seismic design level. As for the pile curvature, the hydrodynamic effect under the low seismic design level may remarkably increase the response by as large as 15%–20%, whereas under the high seismic design level, it has ignorable influence on the pile curvature.

scholarly journals Seismic rocking effects on a mine tower under induced and natural earthquakes

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Piotr Adam Bońkowski ◽  
Juliusz Kuś ◽  
Zbigniew Zembaty
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Ground Surface ◽  
Tall Buildings ◽  
Earthquake Ground Motion ◽  
Seismic Action ◽  
Seismic Effects ◽  
Copper Ore ◽  
Rotational Components ◽  
Natural Earthquakes

AbstractRecent research in engineering seismology demonstrated that in addition to three translational seismic excitations along x, y and z axes, one should also consider rotational components about these axes when calculating design seismic loads for structures. The objective of this paper is to present the results of a seismic response numerical analysis of a mine tower (also called in the literature a headframe or a pit frame). These structures are used in deep mining on the ground surface to hoist output (e.g. copper ore or coal). The mine towers belong to the tall, slender structures, for which rocking excitations may be important. In the numerical example, a typical steel headframe 64 m high is analysed under two records of simultaneous rocking and horizontal seismic action of an induced mine shock and a natural earthquake. As a result, a complicated interaction of rocking seismic effects with horizontal excitations is observed. The contribution of the rocking component may sometimes reduce the overall seismic response, but in most cases, it substantially increases the seismic response of the analysed headframe. It is concluded that in the analysed case of the 64 m mining tower, the seismic response, including the rocking ground motion effects, may increase up to 31% (for natural earthquake ground motion) or even up to 135% (for mining-induced, rockburst seismic effects). This means that not only in the case of the design of very tall buildings or industrial chimneys but also for specific yet very common structures like mine towers, including the rotational seismic effects may play an important role.

scholarly journals Parametric Analysis of Rotational Effects in Seismic Design of Tall Structures

2021 ◽  
Vol 11 (2) ◽  
pp. 597
Author(s):  
Milan Sokol ◽  
Rudolf Ároch ◽  
Katarína Lamperová ◽  
Martin Marton ◽  
Justo García-Sanz-Calcedo
Keyword(s):  
Seismic Design ◽  
Parametric Study ◽  
Tall Buildings ◽  
Soil Parameters ◽  
Eurocode 8 ◽  
Tall Structures ◽  
Rotational Components ◽  
Different Types ◽  
Depth Study

This paper uses a parametric study to evaluate the significance of the rotational components of Earth’s motion in a seismic design. The parametric study is based on the procedures included in Eurocode 8, Part 6. Although the answer to the question of when the effects of rotational components are important is quite a complex one and requires a more in-depth study, our aim was to try to assess this question in a relatively quick manner and with acceptable accuracy. The first part of the paper is devoted to derivation of a simple formula that can be used for expressing the importance of rotational components in comparison with the classic seismic design without their usage. The quasi-static analysis, assuming inertial forces, is used. A crucial role plays the shape of the fundamental mode of the vibration. Due to simplicity reasons, well-known expression for estimation of the first eigenmode as an exponential function with different power coefficients that vary for different types of buildings is used. The possibility of changing the soil parameters is subsequently included into the formula for estimation of the fundamental frequency of tall buildings. In the next part, the overall seismic analyses of complex FEM models of 3D buildings and chimneys are performed. The results from those analyses are then compared with those from simplified calculations. The importance of the soil characteristics for determination of whether it is necessary to take into account the rotational effects is further discussed.

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

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.

scholarly journals Multi-angle and nonuniform ground motions on cable-stayed bridges

2021 ◽  
pp. 875529302110513
Author(s):  
Eleftheria Efthymiou ◽  
Alfredo Camara
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Seismic Waves ◽  
Incidence Angle ◽  
Design Parameters ◽  
System Configuration ◽  
Cable System ◽  
Parametric Problem ◽  
Wide Range ◽  
Cable Stayed Bridges

The definition of the spatial variability of the ground motion (SVGM) is a complex and multi-parametric problem. Its effect on the seismic response of cable-stayed bridges is important, yet not entirely understood to date. This work examines the effect of the SVGM on the seismic response of cable-stayed bridges by means of the time delay of the ground motion at different supports, the loss of coherency of the seismic waves, and the incidence angle of the seismic waves. The focus herein is the effect of the SVGM on cable-stayed bridges with various configurations in terms of their length and of design parameters such as the pylon shape and the pylon–cable system configuration. The aim of this article is to provide general conclusions that are applicable to a wide range of canonical cable-stayed bridges and to contribute to the ongoing effort to interpret and predict the effect of the SVGM in long structures. This work shows that the effect of the SVGM on the seismic response of cable-stayed bridges varies depending on the pylon shape, height, and section dimensions; on the cable-system configuration; and on the response quantity of interest. Furthermore, the earthquake incidence angle defines whether the SVGM is important to the seismic response of the cable-stayed bridges. It is also confirmed that the SVGM excites vibration modes of the bridges that do not contribute to their seismic response when identical support motion is considered.

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