Pedestrian-Induced Vibration of a Simply-Supported Beam

2016 ◽  
Vol 33 (5) ◽  
pp. 577-591 ◽  
Author(s):  
S.-H. Yin
Keyword(s):  
Analytical Approach ◽  
Time History ◽  
Step Length ◽  
Vertical Vibration ◽  
Contact Duration ◽  
Natural Period ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
History Of ◽  
Analytical Relations

AbstractThis paper presents an analytical approach to analyze the vertical vibration of a simply supported beam subjected to pedestrian-induced loads. The loading time history of an individual footstep is simplified as a rectangular force pulse, and each identical footstep load acts at different locations along the beam depending on a step length. Although the loading model is very simple, it enables us to find analytical relations between the pacing parameters and the beam response. The results showed that the dependence of the pacing period, footstep contact duration, time delay of traveling between two pedestrians on the natural period of the beam as well as the step length can influence the dynamic response of the beam significantly.

The Application of E Shaped Steel Bearing on the Simply Supported Beam Bridge

2011 ◽  
Vol 90-93 ◽  
pp. 3141-3144
Author(s):  
Ling Jun Kong ◽  
Yan Bei Chen ◽  
Jun Liu ◽  
Qi Bin Jiang
Keyword(s):  
Computational Models ◽  
Time History ◽  
Earthquake Response ◽  
Bending Moments ◽  
Shear Forces ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Related Data ◽  
Nonlinear Time History ◽  
Beam Bridge

To study the application of E shaped steel bearing on the simply supported beam bridge, the Xinhua bridge is analyzed by the nonlinear time-history method and the Midas/Civil software, considering the interaction between pile and soil. The related data are obtained through two computational models. And the data are compared in this paper. The results show that the bending moments and shear forces of the bottom of the fixed pier are reduced, due to using the E shaped steel bearing at the fixed pier. The E shaped steel bearing dissipates the earthquake energy and reduces the earthquake response of the bridge.

Independent Modal Control of Beams With Spatially Distributed Orthogonal Photostrictive Actuators

2012 ◽  
Author(s):  
Jing Jiang ◽  
Hong-Hao Yue ◽  
Wen-Xiu Cheng ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Light Intensity ◽  
Time History ◽  
High Energy ◽  
Modal Control ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Electrode Shape ◽  
Intensity Control ◽  
Spatially Distributed ◽  
Photostrictive Actuators

High-energy light regulated photostrictive actuators provide a new wireless and non-contact precision actuation mechanism. For PLZT actuators with 0–3 polarization, the electrode shape can be designed to achieve desired modal control effects. In this paper, the photonic control of flexible shells using shaped photostrictive actuators is investigated. Spatially distributed and shaped 0–3 polarized PLZT actuators are selected to achieve independent control of various natural modes of a simply supported beam. Constitutive equations which define the time history response of photo-induced strain for 0–3 polarized PLZT actuator are presented. Based on experimental observation and theoretical analysis, the relationships of saturated photovoltage and time constant with actuator thickness and light intensity are formulated. Based on the orthogonality of the mode shape function, distributed orthogonal modal actuators designed for a simply supported beam are proposed. In order to realize the actuator shape design, paired spatially shaped photostrictive actuators are segmented and respectively placed on the top and bottom surfaces of the beam and the light direction of each segment actuator is regulated. Their control effectiveness with constant light intensity control is evaluated and the time history analysis is presented.

scholarly journals Effect of Material Characteristics of High Damping Rubber Bearings on Aseismic Behaviors of a Two-Span Simply Supported Beam Bridge

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yumin Zhang ◽  
Jiawu Li
Keyword(s):  
Time History ◽  
Bending Moment ◽  
Seismic Energy ◽  
Northridge Earthquake ◽  
Horizontal Shear ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
High Damping Rubber ◽  
Rubber Bearings ◽  
Beam Bridge

There are a large number of damping materials in high-damping rubber (HDR) bearings, so the HDR bearings have the characteristics of both common rubber bearings and damping measures and show good aseismic effect. In this paper, the time-history dynamic analysis method is used to study the seismic effects of HDR bearings on the aseismic behaviors of two-span simply supported beam bridge under Northridge earthquake by changing the damping characteristics of the bearings. It is found that, with increasing damping of the bearings, both the horizontal shear and the displacement of the HDR bearings decrease, and the seismic energy dissipates through both the yield deformation and damping of the bearings. Although the girder and bearings have smaller displacement, when the HDR bearings with larger damping, the seismic responses, including displacement of pier top, shear force of pier bottom, and bending moment of pier bottom, are hardly affected by the change of the damping of the bearings. The HDR bearings with higher damping and yield characteristics separate and dissipate the seismic energy transmitted to the superstructure of the bridge and have better seismic effect on the structure in an earthquake.

scholarly journals The The Effect of Continuous Suspension Constraint on the Free Vibration and Buckling of a Beam

2021 ◽  
Author(s):  
Róbert K. Németh ◽  
Bilal M. A. Alzubaidi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Free Vibration ◽  
Analytical Approach ◽  
Element Analysis ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Frequency Map ◽  
Numerical Finite Element

In this paper, the free vibration and the buckling of a continuously suspended simply-supported beam are analyzed. A semi-analytical approach is used to calculate the natural circular frequencies and the critical forces of the beam. The length of the suspension is used as a parameter, and the natural circular frequencies and the critical forces are presented in a frequency map or a buckling map. The maps are analyzed in view of the trivial solutions, and the frequency map is compared to the map of discrete cable-stayed beams. Finally, for the validation of the results a numerical, finite element analysis is performed.

Analytical Solution for Vertical Dynamic Response of Railway Simply Supported Beam Bridge under Bidirectional Moving Loads

2012 ◽  
Vol 594-597 ◽  
pp. 1552-1556
Author(s):  
Wei Ye ◽  
Xiao Zhen Li ◽  
Hong Duan ◽  
Chun Sheng Shan ◽  
Xiao Han Liu
Keyword(s):  
High Speed ◽  
Vertical Vibration ◽  
Simulation Software ◽  
Dynamic Responses ◽  
Moving Loads ◽  
Simply Supported Beam ◽  
Double Line ◽  
Simply Supported ◽  
Numerical Result ◽  
Beam Bridge

In this thesis, the dynamic responses of simply supported beam bridge in a double-line railway under bidirectional moving loads are mainly studied. To study the characteristics of Euler- Bernoulli beam, a train is simplified as a series of concentrated forces with fixed wheelbase.Structural dynamics is used to deduce the analytical expressions of vertical vibration of simply supported beam under bidirectional moving loads. By simulation software MATLAB, the numerical result of the dynamic responses of simply supported beam bridge could be obtained. Then the 48 meters simply supported beam bridge in a high-speed railway is analyzed, the dynamic responses of simply supported beam of bidirectional moving loads with different interarrival times are discussed.Finally, some general laws for the design of double-line railway bridge are gained.

PROGRAM OF PREDICTION AND MANAGEMENT OF COINTEGED DYNAMIC ECONOMIC PROCESSES BASED ON THE CYBERNETIC APPROACH

2019 ◽  
Author(s):  
Olena Bundak ◽  
Nataliia Zubovetska
Keyword(s):  
Computer Program ◽  
Pair Correlation ◽  
Time History ◽  
Critical Area ◽  
Concrete Object ◽  
Graphic Arts ◽  
Ex Post ◽  
History Of ◽  
Successive Change ◽  
Rms Errors

A method and computer program ConRow, which prognostication of development of the dynamically CPLD economic transients is executed by, is described in the article. Such prognostication of economic processes is very important in the cases when their development can result in undesirable consequences, that to go out in the so-called critical area. Extrapolation in a critical area with the use of information about the conduct of the system at an area, near to it, allows to estimate to the lead through of experiment in the critical area of his consequence. For the imitation of conduct of object the function of review is set on entrance influence. For a concrete object this function can express, for example, dependence of change of level sale from time-history of charges on advertising and set as a numeral row. Statistics as a result of analysis of row are represented in a table, where the level of meaningfulness is set statistician, and also parameters of the handed over criteria. The graphic reflection of information is intended for visualization of analysis. Here represented on the points of graphic arts, the crooked smoothing which are calculated as полиномиальные regressions is added. The best approaching is controlled by sight on the proper graph, and also by minimization of their rms errors. Models of prognostication by sight and as formulas represented on graphic arts, the middle is here determined tailings and their chance is checked up on statistics of signs. After the got models determined also and prognosis values of influences and reviews. Establishing an order models of Сr(p) of co integrate regression is carried out separate custom controls. The coefficient of clay correlation of ruФ shows by itself pair correlation between lines with a successive change in relation to each other on a size to лагу of l = 1, 2, 3 . The program was tested on the example of ex-post prognosis at establishing an integration connection and possibility of prognostication of growth of nominal average monthly settlings on the basis of these statistical indexes of consumer inflation in Ukraine.

scholarly journals Comparison of Novel Seismic Protection Devices to Attenuate the Earthquake Induced Energy

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 73
Author(s):  
Osman Hansu ◽  
Esra Mete Güneyisi
Keyword(s):  
Lateral Displacement ◽  
Time History ◽  
Seismic Protection ◽  
Base Shear ◽  
Seismic Demands ◽  
Nonlinear Time History Analyses ◽  
History Of ◽  
Protection Devices ◽  
Nonlinear Time History ◽  
Better Than

This study addresses an alternative use of viscous dampers (VDs) associated with buckling restrained braces (BRBs) as innovative seismic protection devices. For this purpose, 4-, 8- and 12-story steel bare frames were designed with 6.5 m equal span length and 4 m story height. Thereafter, they were seismically improved by mounting the VDs and BRBs in three patterns, namely outer bays, inner bays, and all bays over the frame heights. The structures were modeled using SAP 2000 software and evaluated by the nonlinear time history analyses subjected to the six natural ground motions. The seismic responses of the structures were investigated for the lateral displacement, interstory drift, absolute acceleration, maximum base shear, and time history of roof displacement. The results clearly indicated that the VDs and BRBs reduced seismic demands significantly compared to the bare frame. Moreover, the all-bay pattern performed better than the others.

scholarly journals Development of a Field Deployable Firebrand Flux and Condition Measurement System

2020 ◽  
Author(s):  
Simone Zen ◽  
Jan C. Thomas ◽  
Eric V. Mueller ◽  
Bhisham Dhurandher ◽  
Michael Gallagher ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Time History ◽  
Infrared Camera ◽  
Thermal Conditions ◽  
Particle Characterization ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
New Instrument ◽  
History Of

AbstractA new instrument to quantify firebrand dynamics during fires with particular focus on those associated with the Wildland-Urban Interface (WUI) has been developed. During WUI fires, firebrands can ignite spot fires, which can rapidly increase the rate of spread (ROS) of the fire, provide a mechanism by which the fire can pass over firebreaks and are the leading cause of structure ignitions. Despite this key role in driving wildfire dynamics and hazards, difficulties in collecting firebrands in the field and preserving their physical condition (e.g. dimensions and temperature) have limited the development of knowledge of firebrand dynamics. In this work we present a new, field-deployable diagnostic tool, an emberometer, designed to provide measurement of firebrand fluxes and information on both the geometry and the thermal conditions of firebrands immediately before deposition by combining a visual and infrared camera. A series of laboratory experiments were conducted to calibrate and validate the developed imaging techniques. The emberometer was then deployed in the field to explore firebrand fluxes and particle conditions for a range of fire intensities in natural pine forest environments. In addition to firebrand particle characterization, field observations with the emberometer enabled detailed time history of deposition (i.e. firebrand flux) relative to concurrent in situ fire behaviour observations. We highlight that deposition was characterised by intense, short duration “showers” that can be reasonably associated to spikes in the average fire line intensity. The results presented illustrate the potential use of an emberometer in studying firebrand and spot fire dynamics.

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