Bridge Section Research Articles

Numerical and Experimental Testing of Normality in the Functioning of the Bearings System

A highly efficient seismic protection of bridges have been demonstrated by the passive control systems with me- chanical links with selective viscoelastic energy dissipation through viscous friction and dry friction. These systems are able to take over the deformations and movements caused by temperature variations, those due to seismic activities and from road traffic. A number of natural factors such as atmospheric and anthropogenic parameters, such as shock and vibration from road traffic, lead to the degradation of the viscoelastic bonds of passive control systems based on rubber molding. The presence of the elastic and dissipative nonlinear forces in the functioning of antiseismic systems inevitably leads to quantitative and qualitative changes of the structural responses of bridges and viaducts both in time and spectral domains. The implications of these changes on the integrity and stability of the bridge or viaduct sections may be from the simplest to the most severe depending on the type of seismic excitation to which they are subjected. For these reasons, it is imperative that we should identify and quantify the degree of nonlinearity of antiseismic systems embedded in the structure of bridges and viaducts in order to prevent accidents with severe socioeconomic implications. In this way can determine the dependence of the nonlinear behavior of the bearing system and the degree of degradation of their viscoelastic links. From a theoretical point of view the following parameters of the vi- bration of the system will be comparatively analyzed: the displacement and acceleration of the bridge deck in time and frequency domains, the hysteretic loop, the representation in the plane of phases, the power spectral density and the spectrograms of the acceleration signals. From an experimental point of view there will be identified and plotted the parameters able to provide information regarding the abnormal operation of the bearings from the elastomer: system acceleration, representations in time and frequency and its spectrogram.

Numerical and Experimental Testing of Normality in the Functioning of the Bearings System

A highly efficient seismic protection of bridges have been demonstrated by the passive control systems with mechanical links with selective viscoelastic energy dissipation through viscous friction and dry friction. These systems are able to take over the deformations and movements caused by temperature variations, those due to seismic activities and from road traffic. A number of natural factors such as atmospheric and anthropogenic parameters, such as shock and vibration from road traffic, lead to the degradation of the viscoelastic bonds of passive control systems based on rubber molding. The presence of the elastic and dissipative nonlinear forces in the functioning of antiseismic systems inevitably leads to quantitative and qualitative changes of the structural responses of bridges and viaducts both in time and spectral domains. The implications of these changes on the integrity and stability of the bridge or viaduct sections may be from the simplest to the most severe depending on the type of seismic excitation to which they are subjected. For these reasons, it is imperative that we should identify and quantify the degree of nonlinearity of antiseismic systems embedded in the structure of bridges and viaducts in order to prevent accidents with severe socioeconomic implications. In this way can determine the dependence of the nonlinear behavior of the bearing system and the degree of degradation of their viscoelastic links. From a theoretical point of view the following parameters of the vibration of the system will be comparatively analyzed: the displacement and acceleration of the bridge deck in time and frequency domains, the hysteretic loop, the representation in the plane of phases, the power spectral density and the spectrograms of the acceleration signals. From an experimental point of view there will be identified and plotted the parameters able to provide information regarding the abnormal operation of the bearings from the elastomer: system acceleration, representations in time and frequency and its spectrogram.

고속도로 비점오염저감시설의 효율적 적용 방안

To build environmentally friendly highways, we testes suitability for unique characteristics of pollution mitigation facility around the highways by evaluating optimal selections and implementation methodologies to minimize loan of non-point pollution substances into water-ways. To do this we categorized EIA target highways into three types ; big drainage basin, small drainage basin, and bridge section as to minimize non-point pollution of highway runoff. The terms of selected facility test based on the Natural and Manufactured Treatment Device were removal efficiency of TSS, BOD, COD, T-N, T-P, compatibility of site selection, economic feasibility, maintenance convenience, and the final mitigation facility.

Buffet suppression in long-span suspension bridges

We study the aerodynamic control of long-span suspension bridges and seek to raise the critical flutter wind speeds, while simultaneously suppressing buffeting. The control system design study is based on a simple flexible bridge section model that interacts with a constant-velocity air stream. A streamlined bridge deck is assumed and non-steady thin aerofoil theory is used to describe the interactions between the bridge deck and the air stream. Classical turbulence models, first developed in the aircraft industry, are used to model the buffet forces acting on the deck. While a wide variety of control systems is possible, we focus on a compensation scheme that can be implemented using passive mechanical components such as springs, dampers and a rack and pinion mechanism. A single-loop control system is investigated that controls a trailing-edge flap by sensing movements of the bridge deck; several such mechanisms are contemplated. The first finding is that the critical wind speed for flutter can be greatly increased, with good robustness characteristics, through passive feedback control. It is also possible simultaneously to suppress flutter using the same passive mechanical controller by solving a passive mixed H 2 / H ∞ control problem. The effect of flexible controller mounting arrangements are considered briefly.

The Singular Function Method Based on the Moving Load Deformation of Suspension Bridge

This paper uses singular function method to analyze the deformation of simplified model of suspension bridge in the moving load, deduces the mathematical equations of the deflection and bending moment, analyzes the simplified model changes of mechanical deformation at different moving load position by using numerical analysis software mathcad,studies the most unfavorable load position and maximum absolute bending moment in a group of concentrated load, gets the results that the maximum absolute bending moment of suspension bridge section depends on the size of the load, mobile location and its distribution in a moving load. The moment influence line used by singular function is smooth segmentation functions. Researching findings provide theoretical basis for the design of suspension bridge.

Experimental evaluation of stress concentration factor of welded steel bridge T-joints

This paper describes an experimental study on determining the stress concentration factor (SCF) and its stochastic characteristics for a typical welded steel bridge T-joint. A full-scale segment model, which holds the same profile with a railway beam section of the suspension Tsing Ma Bridge (TMB) in geometric dimension and material property as well as in weld details, is fabricated and tested. With the measurement data obtained from strain gauges deployed on the web and flanges, the hot spot strain at the weld toe is determined by a linear regression method. The SCF is then calculated as the ratio between the hot spot strain and the nominal strain which is obtained directly by measurement. To fully account for the effect of predominant factors on the scatter of SCF, the experiments are carried out under different moving load conditions. The statistical properties and probability distribution of SCF are derived, which reveals that the SCF for the welded steel bridge T-joint conforms to a normal distribution.

Dynamic increment for shear force due to heavy vehicles crossing a highway bridge

Most of the current research on dynamic amplification factors caused by traffic flow on a bridge has focused on bending moment effects. Although bending stresses often govern the requirements of the bridge section, sufficient shear capacity must be provided too. Shear stresses near the support are strongly influenced by damaged expansion joints and/or differential settlements between the bridge deck and the approach road. The latter is taken into account in this theoretical investigation to evaluate the dynamics associated with the shear load effect caused by heavy trucks and how it relates to the length of the bridge span.

A New Mechanism for Pillar Formation during Tumor-Induced Intussusceptive Angiogenesis: Inverse Sprouting

One of the hallmarks of intussusceptive angiogenesis is the development of intraluminal connective tissue pillars. The exact mechanism of pillar formation has not yet been elucidated. By using electron and confocal microscopy, we observed intraluminal nascent pillars that contain a collagen bundle covered by endothelial cells (ECs) in the vasculature of experimental tumors. We proposed a new mechanism for the development of these pillars. First, intraluminal endothelial bridges are formed. Second, localized dissolution of the basement membrane occurs and a bridging EC attaches to a collagen bundle in the underlying connective tissue. A pulling force is then exerted by the actin cytoskeleton of the ECs via specific attachment points, which contain vinculin, to the collagen bundle, resulting in suction and subsequent transport of the collagen bundle into and through the vessel lumen. Third, the pillar matures through the immigration of connective tissue cells and the deposition of new collagenous connective tissue. The proposed simple mechanism generates a connection between the processes of endothelial bridging and intussusceptive angiogenesis and identifies the source of the force behind pillar formation. Moreover, it ensures the rapid formation of pillars from pre-existing building blocks and the maintenance of EC polarity. To describe it, we coined the term inverse sprouting.

A wavelet-based damage detection algorithm based on bridge acceleration response to a vehicle

Previous research based on theoretical simulations has shown the potential of the wavelet transform to detect damage in a beam by analysing the time-deflection response due to a constant moving load. However, its application to identify damage from the response of a bridge to a vehicle raises a number of questions. Firstly, it may be difficult to record the difference in the deflection signal between a healthy and a slightly damaged structure to the required level of accuracy and high scanning frequencies in the field. Secondly, the bridge is going to have a road profile and it will be loaded by a sprung vehicle and time-varying forces rather than a constant load. Therefore, an algorithm based on a plot of wavelet coefficients versus time to detect damage (a singularity in the plot) appears to be very sensitive to noise. This paper addresses these questions by: (a) using the acceleration signal, instead of the deflection signal, (b) employing a vehicle–bridge finite element interaction model, and (c) developing a novel wavelet-based approach using wavelet energy content at each bridge section, which proves to be more sensitive to damage than a wavelet coefficient line plot at a given scale as employed by others.

Experimental Study of Static Aerodynamic Coefficients of Bridge Section

With HK-Zhuhai-Macau Bridge as the engineering background, through the section model wind tunnel test, research into the influence of vibration damping measure to the static aerodynamic coefficients of the structure, so as to seek to improve structural characteristics. The influencing factors of static aerodynamic coefficients including the guide plate position, the central trough opening rate, baluster drafty rate, repair car track position, windbreak, and vehicle. The results show that the changes of the static aerodynamic coefficients directly affect the static wind loads, and the influence of changes of these parameters to the static wind load cannot be ignored.

유한요소해석을 통한 장간조립교 주요 부재의 안정성 분석 연구

In this paper, the results of computational analysis for the stability and F.S.(Factor of Safety) of Bailey Panel Bridge have been presented by FEM(Finite Element Method). The computational analysis was conducted by using LUSAS V14.0 that is a program applicated in the field of Civil Engineering. 6-free beam elements and 3-free truss elements were considered and F.S. against Yield Stress of main sections(considered self-weight and Live-Load) was investigated through the linear-elastic analysis method. The results showed that currently used sections of bailey bridge satisfied for the standard F.S. unit and could be operated in drill of troops and battle fields.

A multiresolution remeshed Vortex-In-Cell algorithm using patches

We present a novel multiresolution Vortex-In-Cell algorithm using patches of varying resolution. The Poisson equation relating the fluid vorticity and velocity is solved using Fast Fourier Transforms subject to free space boundary conditions. Solid boundaries are implemented using the semi-implicit formulation of Brinkman penalization and we show that the penalization can be carried out as a simple interpolation. We validate the implementation against the analytic solution to the Perlman test case and by free-space simulations of the onset flow around fixed and rotating circular cylinders and bluff body flows around bridge sections.

Theoretical Analysis of Temperature and Shrinkage Stresses of Box-Girder Section

The objective of this study is to analyze the temperature and shrinkage stresses of the mid-span cross-section of a 20 meters box girder to find the reasons which cause the longitudinal cracks in the web and bottom of box girder. According to the results of damage inspeation, there are many longitudinal cracks in the web and bottom slab of box girders, especially the web of the edger beam, the crack is very clear. Ansys ver.10 software is used to analyze two dimensional finite element model of a typical cross section of a real bridge to calculate the temperature stresses caused by temperature difference between inside and out side of the box and the shrinkage stresses based on moisture diffusion. The results of analysis show that the outer surface of the web and bottom slab of the fabricated box girder will produce tensile stress at the effect of negative temperature difference. If the concrete reaches a certain age, the tensile stress does not cause creaks in the cross-section. The shrinkage stress changes with the moisture gradient in the box section. It will reach the maximum in 15 days and then decreases with the growth of the age. Shrinkage stress may cause cracking of the concrete surface because of the tensile strength is low in the early age.

Aeroelastic Control of Long-Span Suspension Bridges

The modeling, control, and dynamic stabilization of long-span suspension bridges are considered. By employing leading- and trailing-edge flaps in combination, we show that the critical wind speeds for flutter and torsional divergence can be increased significantly. The relatively less well known aerodynamic properties of leading-edge flaps will be studied in detail prior to their utilization in aeroelastic stability and control system design studies. The optimal approximation of the classical Theodorsen circulation function will be studied as part of the bridge section model building exercise. While a wide variety of control systems is possible, we focus on compensation schemes that can be implemented using passive mechanical components such as springs, dampers, gearboxes, and levers. A single-loop control system that controls the leading- and trailing-edge flaps by sensing the main deck pitch angle is investigated. The key finding is that the critical wind speeds for flutter and torsional divergence of the sectional model of the bridge can be greatly increased, with good robustness characteristics, through passive feedback control. Static winglets are shown to be relatively ineffective.

Beitrag zur Entwicklung der Querschnittsgestaltung im Verbundbrückenbau

AbstractDie grafische Darstellung des Verbundquerschnittes mit einer oberen Betonplatte und einem darunter liegenden Stahlträger war seit seiner Vorstellung in den 1950er Jahren ein Symbol, das weit über die Theorie hinausging und weite Verbreitung in der Praxis des Verbundbrückenbaus fand. Seit den 1970er bzw. 1980er Jahren hat dieses Bild – bedingt durch neue und freiere Formen, Beton und Stahl miteinander zu kombinieren – seine Symbolhaftigkeit verloren. In Deutschland und Spanien wurde der Doppelverbund mit unten liegenden Betonplatten in Bereichen mit negativen Momenten eingeführt, in Frankreich werden Stahlträger auch in vorgespannten Betonquerschnitten eingebettet. Beide Ansätze haben dazu beigetragen, dass in der Gegenwart die Materialien Stahl und Beton im Verbundbau frei miteinander kombiniert werden können.On the development of sections in composite bridges. A comprehensive theory of composite construction was established in Germany by Sattler in 1953. The theoretical image of the composite section with a superior concrete slab and a lower metallic structure was shaped in addition to the analytical resolution. Theory and graphical representation were going to be known together in Europe. This figure was repeated in all theoretical and academic publications, so becoming an authentic icon of the composite section. Its translation to the bridge deck in flexion was obvious: the superior slab defines the tread platform, while the metallic structure was left off‐hook at the bottom.Nevertheless, in continuous decks the section is not optimal at all in zones of negative bending moments. But the overcoming of the graphical representation of the theory did not happen immediately. It was produced after a process in which several European countries played an active role and where different mechanisms of technological transference were developed.One approach to this overcoming is the “double composite action”, with a lower concrete slab in areas of a negative bending moment. The first accomplishments, a bridge in Orasje built in 1968 with 134 m span, as well as the publications of the system proposed by Fabrizio de Miranda in 1971 did not extend nor had continuity. Spanish bridges by Fernández Ordoñez and Martínez Calzón used double composite action for the first time in 1979. The German team of Leonhard, Andrä und partners, has used it since the end of the 1980's to solve bridges of great span. Once the technology has been well known thanks to the ASCE International Congress and the Spanish International Meetings organised by the “Colegio de Ingenieros de Caminos”, double composite action has been integrated well into the structural vocabulary everywhere.In France the approach was different. What Michel Virlogeux calls “double floor composite section” was reached as an evolution of prestressed concrete bridges. In an experimental process widely known, the external prestressing allows weight reduction by diminishing the thickness of the concrete webs. The following step, in the 1980's, was the substitution of the webs by metallic elements: stiffened plates, trusses or folded plates. A direct result of this development is the Brass de la Plaine Bridge in the Reunion Island in 2001 with 280 m span.Both approaches have contributed to a freedom of design in composite construction in steel and concrete today.

장간조립교 주요 부재의 강도 분석 연구

In this paper, the results of experimental analysis for the chemical composition and strengh verification of Bailey Panel Bridge have been presented. Some of main sections of bailey bridge colllected from military engineer troops were prepared for the chemical composition and strengh verification. The composition test and strength verification were conducted by using the optical microscope and Scanning Electron Microscope(SEM), Automatic Control Spark Emission Spectrometer(OBLF), X-ray Fluorescence Spectroscopy(XRF) and Instron measurement. The results showed that currently used sections of bailey bridge passed the strength verification and could be operated in drill of troops and battle fields.

Decoupling Free Vibration System of Bridge Section Model

In the paper the free vibration system of bridge section model is designed in order to measure the wind-induced effects on the bridge section model in the wind tunnel. In the system the suspension device is constituted with decoupling sliding components and simple spring suspension. Meanwhile, a set of data measurement and acquisition device based on the Labview is provided in the system. The measurement on the wind-induced static force, flutter and vortex-induced vibration of the bridge section model can be conducted at single degree of freedom or multiple degrees of freedom.

Applying ANFIS to Estimate Stream-Way Erosion

The particular geological conditions of Taiwan and the onset of global climate change, have increased the intensity of precipitation, leading to greater turbulence within river channels. The erosion of riverbeds is an on-going concern, as the movement of sediment is at an all-time high. This study employs adaptive-network-based fuzzy inference to analyze and predict the erosion of river channels, and compares the results with those obtained through traditional linear regression. The Houfeng Bridge section of the Ta-Chia River in Taiwan was adopted as a case study. We investigated flow rate, gradient change, the quantity of sediment, the number of typhoons and floods, and geological conditions, as major causal factors of erosion. Results indicate that under heavy turbulence, the potential for erosion is very high in the flow areas of both Houfeung Bridge and the Chenglung Revetment. Our results are consistent with the actual conditions at the site.

<i>Hart Crane: After His Lights</i> (review)

Hart Crane: After His Lights. Brian Reed. Tuscaloosa: U of Alabama P, 2006. viii+312 pp. $65.00 (cloth). This good book about Hart Crane's poetry - the first monograph on in over ten years, and the first since Langdon Hammer's big edited volume of Crane's letters (O My Land My Friends, New York: Four Walls Eight Windows, 1997) - pursues three strong arguments, and one weak one. All four might change (at least slightly) how we read other modernist poets, Williams among them. first strong argument has to do with Crane's forebears: prior critics have almost uniformly found his models in an American Romantic tradition stemming from Ralph Waldo Emerson and Walt Whitman. Reed shows that Crane's preoccupations, his meters and stanzas, and his whole way of thinking about what poems can do, owe to the late nineteenth century's British Decadents - to Oscar Wilde (whom Crane's first published poem memorialized) but above all to Algernon Charles Swinburne, whom read avidly and imitated covertly. This mannerist (17) legacy makes look more 'British' in his poetic sensibility than scholars have heretofore seen (27). Pursuing the sexual implications of decadent styles, Reed also likens to Djuna Barnes, both queer writers whose 'broken' decadent forms [. . .] acknowledge the obsolescence, the ruination, of fin de siecle camp (51) in the wake of the Wilde trials. semantically shaky, aurally lush, sometimes redundant verbal world of Swinburne - especially of his now little-read long poems - helps show why Crane's poems sound as they do: it might prompt critics even of such defiantly American writers as Williams to ask what other transatlantic links we have missed. (There's so much of the Spanish stuff that is unknown, old and new, Williams told James Laughlin [SL 1 83]; despite such studies as Julio Marzan's Spanish American Roots of William Carlos Williams [Austin: U of Texas P, 1994], that may still be the case.) Reed's second, and ambitious, argument connects Crane's poetic innovations to the history of music, and to the history of technology. composed with a phonograph at top volume, playing nineteenth- and twentieth-century opera and orchestral music (such as Ravel's Bolero) if available, the day's pop hits if not. These earsplitting, sometimes drunken bouts of writing while the same 78 played, over and over, preceded - for the poems regarded as finished - sober sessions of editing and revision. This part of Reed's study displays simultaneous and majestic commands of biographical and manuscript minutiae, of musicology and reception history (what did Wagner signify in America in 1 923?) and of the history of recording (how did most people listen to 78s in the 1920s? how much music fit on each side?). Reed finds both an analogy, and a homology, between the ways Crane's words work, on the one hand, and on the other the Craneian experience of hearing - out of sequence and repeated ad lib, pared down, and strung - short parts of operatic and orchestral compositions, as would have heard them on his post-Edison but pre-LP 78s (122-23). Here is historical, multidisciplinary scholarship at its best. It turns out to be biographical scholarship too, since Crane treat[ed] his romance with [the sailor Emil] Opffer in the same manner that he treated Bolero, repeating its erotic buildup over and over, with no clear sense of plot, and no finale (115). Crane's modes of listening and his tastes in nineteenth-century poetry together let Reed explain, and celebrate, the absence of something Crane's earlier critics sought: an implied development, or argument, or plot, among the sections of Bridge. There isn't one; there doesn't have to be (and it might be heterosexist to think otherwise). Swinburne's long poem Tristram of Lyonesse attempts to transpose Wagnerian instrumentation into English verse, and The Bridge often sounds like Tristram [. …

Identification of Flutter Derivatives of Bridge Deck Under Multi-Frequency Vibration

:A multi-frequency vibration method (MFVM) is proposed to identify flutter derivatives of bridge deck. In this method, a bridge deck is forced in vertical or torsional harmonic vibration with linear combination of multi-frequency. Computational Fluid Dynamic (CFD) simulation is conducted using 2D unsteady incompressible Navier-Stokes equations combined with renormalization group (RNG) k  turbulence model, based on improved domain decomposition method. The non-dimensional time histories of lift and moment are fitted by least square method to identify the flutter derivatives of bridge deck. Flutter derivatives of a thin flat plate and the 2nd Nanjing Yangtze River Bridge section are computed. The results are in good agreement with Theodorsen’s theory and wind tunnel test data, which demonstrates the reliability and efficiency of the present approach.