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Compression Stress (compression + stress)
Selected AbstractsMechanics of column beds: II.AICHE JOURNAL, Issue 3 2003Modeling of coupled stress-strain-flow behavior The rheological behavior of a bed of packing material during its consolidation was investigated using an elastic-plastic model, the Frictional Material Model. This model takes into account the behavior of the packing material under compression stress, its consolidation, its internal friction, its friction against the column wall, and the dependence of the bed's permeability on the local void fraction. The complexity of the problem arises from the nonlinear behavior of the relationships between the critical parameters controlling the column bed behavior and the external stresses applied to this bed. Solutions of the model were calculated for combinations of axial compression and seepage stresses, the latter corresponding to the flow of the mobile-phase stream under typical conditions used in HPLC. The results demonstrate the importance of the internal angle of friction of the packing material used on the degree of radial and axial heterogeneity of the beds of chromatographic columns packed with this material. [source] Knotengestaltung hybrider Fachwerkkonstruktionen , Entwicklung neuartiger Tragwerkskonzepte unter Verwendung von Ultrahochleistungsbeton (UHFB)BAUTECHNIK, Issue 5 2006Nguyen Viet Tue Prof. Dr.-Ing. habil. Fachwerkkonstruktionen zählen zu den leistungsfähigsten raumbildenden Strukturen der Baugeschichte. Rein normalkraftbeanspruchte Bauteile zeichnen sich vor allem durch minimalen Werkstoffaufwand aus. Die Einsatzgebiete von Fachwerken sind so vielgestaltig wie deren Ausführungsformen selbst. Gerade in den letzten Jahren gewinnen Fachwerkkonstruktionen z. B. beim Bau transparenter Hochhäuser oder für Stadien und Veranstaltungsarenen und vereinzelt auch wieder im Brückenbau, verstärkt an Bedeutung. Mit finanzieller Unterstützung der Bilfinger | Berger AG wurde an der Universität Leipzig ein stabförmiges Verbundbauteil aus einem stahlummantelten ultrahochfesten Beton entwickelt. Das neue Tragelement kennzeichnet sich durch seine hohe Tragfähigkeit unter Druckbeanspruchung sowie großer Duktilität. Dieser hybride Verbundstab stellt, einschließlich einer innovativen Knotenlösung, eine sinnvolle, wirtschaftliche und vor allem architektonisch ansprechende Alternative zu den herkömmlich konstruierten Fachwerken, dar. In diesem Beitrag wird über die Besonderheiten dieser Konstruktionsform sowie über die Entwicklung geeigneter Knoten berichtet. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Design of joints for hybrid truss structures. Truss constructions belong to the most efficient spatial structures in building history. Purely longitudinal stressed members are characterized by a minimum material expense. The application areas of truss members are as multiform as their embodiment. Recently, truss constructions increase importance due to their application within transparent tall buildings, stages, arenas, bridges etc. With the financial support of Bilfinger | Berger AG, at the University of Leipzig a bar-shaped composite member was developed using a steel-encased Ultra High Performance Concrete (UHPC). This new structural member is distinguished by its high load carrying capacity under compression stress as well as high ductility. Including an innovative joint solution, this hybrid composite bar is a reasonable, economic, and above all, an architectural appealing alternative to a conventionally designed truss structure. In the following contribution, some features of this member and the development of appropriate joints are described. [source] Langjährige Messung von Kraft- und Verformungsgrößen in Neotopf-Gleitlagern einer Spannbetonstraßenbrücke.BETON- UND STAHLBETONBAU, Issue 12 2006Brückenlager-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] Structural Characteristics and Formation Mechanism in the Micangshan Foreland, South ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2009Huaming XU Abstract: Lying at the junction of the Dabashan, Longmenshan and Qinling mountains, the Micangshan Orogenic Belt coupled with a basin is a duplex structure and back-thrust triangular belt with little horizontal displacement, small thrust faults and continuous sedimentary cover. On the basis of 3D seismic data, and through sedimentary and structural research, the Micangshan foreland can be divided into five subbelts, which from north to south are: basement thrust, frontal thrust, foreland depression-back-thrust triangle, foreland fold belt or anticline belt, and the Tongjiang Depression. Along the direction of strike from west to east, the arcuate structural belt of Micangshan can be divided into west, middle and east segments. During the collision between the Qinling and Yangtze plates, the Micangshan Orogenic Belt was subjected to the interaction of three rigid terranes: Bikou, Foping, and Fenghuangshan (a.k.a. Ziyang) terranes. The collision processes of rigid terranes controlled the structural development of the Micangshan foreland, which are: (a) the former collision between the Micangshan-Hannan and Bikou terranes forming the earlier rudiments of the structure; and (b) the later collision forming the main body of the structural belt. The formation processes of the Micangshan Orogenic Belt can be divided into four stages: (1) in the early stage of the Indosinian movement, the Micangshan-Hannan Rigid Terrane was jointed to the Qinling Plate by the clockwise subduction of the Yangtze Plate toward the Qinling Plate; (2) since the late Triassic, the earlier rudiments of the Tongnanba and Jiulongshan anticlines and corresponding syncline were formed by compression from different directions of the Bikou, Foping and Micangshan-Hannan terranes; (3) in the early stage of the Himalayan movement, the Micangshan-Hannan Terrane formed the Micangshan Nappe torwards the foreland basin and the compression stresses were mainly concentrated along both its flanks, whereas the Micangshan-Hannan Terrane wedged into the Qinling Orogenic Belt with force; (4) in the late stage of the Himalayan movement, the main collision of the Qinling Plate made the old basement rocks of the terrane uplift quickly, to form the Micangshan Orogenic Belt. The Micangshan foreland arcuate structure was formed due to the non-homogeneity of terrane movement. [source] | ||||||||||