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Sliding Bearings (sliding + bearing)

Distribution by Scientific Domains

Engineering	100%

Selected Abstracts

Langjährige Messung von Kraft- und Verformungsgrößen in Neotopf-Gleitlagern einer Spannbetonstraßenbrücke.

BETON- UND STAHLBETONBAU, Issue 12 2006
Brückenlager-Monitoring
Zwei Lager der dreifeldrigen Spannbeton-Straßenbrücke über den Aasee in Münster wurden beim Bau in den Jahren 1987/88 als Neotopf-Gleitlager mit Meßeinrichtungen ausgestattet, die den Gleitspalt und den Kippspalt messen. Außerdem ist eine Druckmeßdose eingebaut worden, die den Druck des Silikonöls im Stahltopf unter dem Elastomer mißt. Mit diesen Meßeinrichtungen wurde die Lastgeschichte der Lager während der Bauzeit festgestellt. Im Laufe der 18jährigen Standzeit der Brücke wurden die Lager mit diesen Meßeinrichtungen überwacht. Nach der Fertigstellung der Brücke und in Abständen von einigen Jahren sind Zustandgrößen der Lager im Sinne eines Monitoring auch durch Überfahren der Brücke mit Lastkraftwagen gemessen worden. Die Lager weisen nach 18 Jahren nur geringfügige Abnutzung auf. Longterm Measuring of Forces and Displacements in Elastomer Pot Sliding Bearings of a Prestressed Concrete Road Bridge. Monitoring of Bridge Bearings Two bearings of a three span prestressed concrete road bridge over the lake Aa in the City of Münster were equipped with elastomer pot sliding bearings with measuring devices during the erection in 1987/88, that are able to measure the distance between sliding slab and covering slab and the rotation of the covering slab. Moreover there are dynamometers, which measure the compression stress of the silicone oil in the pot under the elastomer. With these measuring devices the load history of the bearings during the time of erection of the bridge was monitored. In the 18 years that the bridge is in operation, the bearings have been monitored with these measuring devices. Following the completion of the bridge and further in intervals of some years the loads and displacements of the bearings were monitored especially during lorries were crossing the bridge. The bearings show only minimal attrition after 18 years in use. [source]

The eigenvalues of isolated bridges with transverse restraints at the end abutments

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2010
Nicos Makris
Abstract This paper examines the eigenvalues of multi-span seismically isolated bridges in which the transverse displacement of the deck at the end abutments is restricted. With this constraint the deck is fully isolated along the longitudinal direction, whereas along the transverse direction the deck is a simple-supported beam at the end abutments which enjoys concentrated restoring forces from the isolation bearings at the center piers. For moderate long bridges, the first natural period of the bridge is the first longitudinal period, while the first transverse period is the second period, given that the flexural rigidity of the deck along the transverse direction shortens the isolation period offered by the bearings in that direction. This paper shows that for isolated bridges longer than a certain critical length, the first transverse period becomes longer than the first longitudinal period despite the presence of the flexural rigidity of the deck. This critical length depends on whether the bridge is isolated on elastomeric bearings or on spherical sliding bearings. This result is also predicted with established commercially available numerical codes only when several additional nodes are added along the beam elements which are modeling the deck in-between the bridge piers. On the other hand, this result cannot be captured with the limiting idealization of a beam on continuous distributed springs (beam on Wrinkler foundation),a finding that has practical significance in design and system identification studies. Finally, the paper shows that the normalized transverse eigenperiods of any finite-span deck are self-similar solutions that can be represented by a single master curve and are independent of the longitudinal isolation period or on whether the deck is supported on elastomeric or spherical sliding bearings. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Spherical sliding isolation bearings with adaptive behavior: Experimental verification

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 2 2008
Daniel M. Fenz
Abstract This paper describes an experimental program to examine the force,displacement behavior of a class of multi-spherical sliding bearings. The primary goal of the experiments is to test the validity of the theory developed in a companion paper that describes the behavior of these devices. Experimental work consisted of testing the three primary variations of these bearings in several configurations of different friction and displacement capacities. Most tests were carried out at slow speeds; however, some testing was also conducted at high speed (up to approximately 400,mm/s) to examine the behavior under dynamic conditions. The results of experimental testing were generally found to be in very good agreement with the analytical results. It is shown that the forces and displacements at which transitions in stiffness occur are predictable and therefore controllable in design. Furthermore, the underlying principles of operation were confirmed by the fact that starting and stopping of sliding on the different surfaces occurred as expected from theory. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Erdbebenertüchtigung des Feuerwehrgebäudes in Basel durch schwimmende Lagerung

BAUTECHNIK, Issue 8 2009
Hugo Bachmann Prof. Dr. sc. techn.
Baumechanik; Bauwerkserhaltung/Sanierung; Structural Mechanics; Maintenance and Renovation Abstract Kürzlich wurde das Hauptgebäude der Berufsfeuerwehr Basel-Stadt aus dem Jahre 1943 auf spezielle Erdbebenlager aus Gummi und auf Gleitlager gestellt. Es handelt sich um die erste derartige Erdbebenertüchtigung eines bestehenden Gebäudes nördlich der Alpen. Im Vergleich zu einer konventionellen Verstärkung waren die Baukosten bedeutend geringer, und es war keine temporäre Ausquartierung des Betriebes in ein teures Provisorium erforderlich. Zudem ist die resultierende Erdbebensicherheit erheblich größer und die Schadensanfälligkeit bei schweren Erdbeben wesentlich geringer als es bei einer konventionellen Verstärkung der Fall wäre. Seismic upgrading of the fire brigade building in Basel by base isolation. Recently, the main building of the professional fire brigade of the city and canton Basel-Stadt built in the year 1943 was placed on special seismic elastomeric bearings and on sliding bearings. This is the first such seismic upgrading of an existing building in the north of the Alps. Compared to a conventional strengthening the buildingcosts were significantly smaller, and no temporary transfer of the operation into an expensive provisional building was necessary. Moreover, the resulting seismic safety is considerably higher and the vulnerability to a severe earthquake essentially smaller than in case of a conventional strengthening. [source]