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Highway Bridge (highway + bridge)

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Engineering100%

Selected Abstracts

Experimental and analytical study on pounding reduction of base-isolated highway bridges using MR dampers

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 11 2009
Anxin Guo
Abstract Pounding between adjacent superstructures has been a major cause of highway bridge damage in the past several earthquakes. This paper presents an experimental and analytical study on pounding reduction of highway bridges subjected to earthquake ground motions by using magnetorheological (MR) dampers. An analytical model, which incorporates structural pounding and MR dampers, is developed. A series of shaking table tests on a 1:20 scaled base-isolated bridge model are performed to investigate the effects of pounding between adjacent superstructures on the dynamics of the structures. Based on the test results, the parameters of the linear and the nonlinear viscoelastic impact models are identified. Performance of the semiactive system for reducing structural pounding is also investigated experimentally, in which the MR dampers are used in conjunction with the proposed control strategy, to verify the effectiveness of the MR dampers. Structural responses are also simulated by using the established analytical model and compared with the shaking table test results. The results show that pounding between adjacent superstructures of the highway bridge significantly increases the structural acceleration responses. For the base-isolated bridge model considered here, the semiactive control system with MR dampers effectively precludes pounding. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Cyclic tests on large-scale models of existing bridge piers with rectangular hollow cross-section

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 13 2003
A. V. Pinto
Abstract Cyclic tests on two large-scale models of existing bridge piers with rectangular hollow cross-section were performed in the ELSA laboratory. The prototype structure is an existing reinforced concrete highway bridge constructed in Austria in 1975. The piers presented several seismic deficiencies and consequently they showed poor hysteretic behaviour and limited deformation capacity as well as undesirable failure modes that do not comply with the requirements of modern codes for seismic-resistant structures. Experimental data are compared to numerical and empirical predictions. Copyright © 2003 John Wiley & Sons, Ltd. [source]

An integrated parameter identification method combined with sensor placement design

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 12 2008
Yiqian Li
Abstract Material parameter identification based on in situ measurements plays a very important role in engineering. Since noises are inevitable in measurements and the parameter identification is inherently ill posed, it is necessary to consider some methods to stabilize the identification procedure. One choice is properly designing the sensor placement, which has attracted much attention over the past 30 years. Most existing sensor placement design methods are based on certain sensitivity analysis, which commonly requires evaluating Jacobian matrix for given parameters. However, the ,true' values of parameters are unknown at that moment, because sensor placement design is carried out before the parameter identification. Consequently, roughly estimated ,true' parameters have to be used and less optimal sensor placement could be obtained. To solve this problem, this paper presents an integrated method in which the parameter identification and sensor placement design are carried out alternatively. The validity of the proposed method is illustrated by two simple academic examples. Then it is implemented to detect damages in a real highway bridge. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Experimental and analytical study on pounding reduction of base-isolated highway bridges using MR dampers

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 11 2009
Anxin Guo
Abstract Pounding between adjacent superstructures has been a major cause of highway bridge damage in the past several earthquakes. This paper presents an experimental and analytical study on pounding reduction of highway bridges subjected to earthquake ground motions by using magnetorheological (MR) dampers. An analytical model, which incorporates structural pounding and MR dampers, is developed. A series of shaking table tests on a 1:20 scaled base-isolated bridge model are performed to investigate the effects of pounding between adjacent superstructures on the dynamics of the structures. Based on the test results, the parameters of the linear and the nonlinear viscoelastic impact models are identified. Performance of the semiactive system for reducing structural pounding is also investigated experimentally, in which the MR dampers are used in conjunction with the proposed control strategy, to verify the effectiveness of the MR dampers. Structural responses are also simulated by using the established analytical model and compared with the shaking table test results. The results show that pounding between adjacent superstructures of the highway bridge significantly increases the structural acceleration responses. For the base-isolated bridge model considered here, the semiactive control system with MR dampers effectively precludes pounding. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Effect of variation of normal force on seismic performance of resilient sliding isolation systems in highway bridges

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 15 2005
Hirokazu Iemura
Abstract In this study, a series of shaking table tests are carried out on scaled models of two seismically isolated highway bridges to investigate the effect of rocking motion and vertical acceleration on seismic performance of resilient sliding isolators. In addition, performance of RSI is compared with system having solely natural rubber bearings. Test results show that variation of normal force on sliders due to rocking effect and vertical acceleration makes no significant difference in response of RSI systems. In addition, analytical response of prototype isolated bridge and the model used in experiments is obtained analytically by using non-linear model for isolation systems. It is observed that for seismically isolated bridges, dynamic response of full-scale complex structures can be predicted with acceptable accuracy by experiments using a simple model of the structure. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Anpassung des Verkehrslastmodells des DIN FB 101 für kommunale Brücken

BETON- UND STAHLBETONBAU, Issue 5 2007
Balthasar Novák Prof. Dr.-Ing.
Für den Verantwortungsbereich des BMVBS ist das kürzlich eingeführte Lastmodell LM1 für die Verkehrslasten auf Brücken ohne weitere Reduktionen für alle neuen Brückenbauwerke anzusetzen. Dies führt jedoch leider gerade im Bereich der Kommunen zu teilweise konservativen Ergebnissen, da die geometrischen Abmessungen von kommunalen Brücken deutlich von den "üblichen" Abmessungen von Autobahnen und Bundesstraßen abweichen können und die Belastung aus dem LM1 durch den realen Verkehr nicht erzeugt werden kann. Es werden Vorschläge präsentiert, wie bei bestimmten geometrischen Randbedingungen und abhängig vom statischen System eine weitere Abminderung des LM1 möglich ist, ohne das Sicherheitsniveau zu verlassen. Die Arbeit entstand in enger Zusammenarbeit mit den Städten Frankfurt/Main, Leipzig und Stuttgart. Adjusted Traffic Load for Bridges under Communal Responsibility Recently the traffic loads of bridges of the EC1 have been introduced in Germany under the responsibility of the Federal Ministry of Transport, Building and Urban Affairs. Usually the Load Model LM1 has to be used for all new bridge structures with the adjusted values of ,Q1 = 0, 8, ,Q2 = 0, 8, ,Q3 = 0. A further classification has not been defined. This makes sense for the highway bridges and federal road bridges, because usually they have longer spans where a further reduction of the ,-values is not justified. In the sphere of influence of cities and villages the situation is totally different, because many bridges are short and are buildt as single span girder bridges or single frame bridges. In case of those bridges the LM1 leads to conservative results because the geometry and the total weight and the axle weight of the real lorries are limited and cannot develop those high inner forces and moments. The authors developed a proposal for further reduction of the ,-values dependent on the geometry and the statical system of the bridge without leaving the safety level of the Eurocode. Also for strengthening existing bridges these values can be used. The development has been undertaken in colaboration with the civil engineering offices in Frankfurth/Main, Leipzig and Stuttgart. [source]