Reinforced Concrete Frame (reinforced + concrete_frame)

Distribution by Scientific Domains


Selected Abstracts


Shaking table tests on reinforced concrete frames without and with passive control systems

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2005
Mauro Dolce
Abstract An extensive experimental program of shaking table tests on reduced-scale structural models was carried out within the activities of the MANSIDE project, for the development of new seismic isolation and energy dissipation devices based on shape memory alloys (SMAs). The aim of the experimental program was to compare the behaviour of structures endowed with innovative SMA-based devices to the behaviour of conventional structures and of structures endowed with currently used passive control systems. This paper presents a comprehensive overview of the main results of the shaking table tests carried out on the models with and without special braces. Two different types of energy dissipating and re-centring braces have been considered to enhance the seismic performances of the tested model. They are based on the hysteretic properties of steel elements and on the superelastic properties of SMAs, respectively. The addition of passive control braces in the reinforced concrete frame resulted in significant benefits on the overall seismic behaviour. The seismic intensity producing structural collapse was considerably raised, interstorey drifts and shear forces in columns were drastically reduced. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Seismic tests on reinforced concrete and steel frames retrofitted with dissipative braces

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 15 2004
F. J. Molina
Abstract Seismic tests have been conducted on two 3-storey structures protected with pressurized fluid-viscous spring damper devices. One of the structures was a reinforced concrete frame with clay elements in the slabs, while the other one was a steel frame with steel/concrete composite slabs. The spring dampers were installed through K bracing in between the floors. The tests were performed by means of the pseudodynamic method, which allowed the use of large and full-size specimens, and by implementing a specific compensation strategy for the strain-rate effect at the devices. The test results allowed the verification of the adequacy of the attachment system as well as the comparison of the behaviour of the unprotected buildings with several protected configurations, showing the benefits of the application of the devices and the characteristics of their performance. The response of the protected structures was always safer than that of the unprotected ones mainly due to a significant increase of equivalent damping. The increase in the damping ratio depends on the level of deformation. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Proportioning earthquake-resistant RC frames in central/eastern U.S.

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2002
JoAnn Browning
Abstract A maximum allowable period criterion is used to determine reasonable stiffness requirements for reinforced concrete frames with the seismicity associated with central and eastern U.S. A general relationship is developed to describe the displacement demand expected for central and eastern U.S. based on a survey of available ground motions, opinions of seismologists, and code-based provisions. A series of hypothetical reinforced concrete frames is proportioned using a maximum allowable period criterion and evaluated for expected maximum displacement response using non-linear dynamic analyses and a suite of ground motions. Results indicate that for the reinforced concrete structural systems considered in the study, proportioning for gravity loads will provide sufficient stiffness in central and eastern U.S. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Kombiniertes Verfahren zur wirklichkeitsnahen Berechnung schlanker Stahlbetonstabtragwerke

BETON- UND STAHLBETONBAU, Issue 10 2006
Uwe Starossek Univ.-Prof.
Der wirklichkeitsnahen und damit nichtlinearen Berechnung von allgemeinen Stahlbetontragwerken kommt eine wachsende Bedeutung zu. Eine Kombination des allgemeinen Weggrößenverfahrens, des Übertragungsverfahrens und eines Querschnittsmoduls führt zu einem effektiven Berechnungsverfahren für allgemeine Stabtragwerke aus Stahl- und Spannbeton. Neben der stofflichen Nichtlinearität berücksichtigt das Verfahren auch geometrische Nichtlinearität mit großen Verformungen. Die übergeordnete Berechnung des Systems erfolgt inkrementell und iterativ mit dem allgemeinen Weggrößenverfahren. Auf Stabebene wird ein erweitertes Übertragungsverfahren zur Bestimmung der Stabendschnittgrößen und der Steifigkeitsmatrix eingesetzt. Die Formulierung des Übertragungsverfahrens erfolgt in einem rekursiven Schema für einen verformten Stab, der in Abhängigkeit vom Steifigkeitsgradienten in einzelne Abschnitte diskretisiert wird. Das nichtlineare Materialverhalten einschließlich Rißbildung, Entfestigung und Fließen der Bewehrung wird im Querschnittsmodul über eine Querschnittsintegration erfaßt. Combined method for a realistic analysis of slender reinforced concrete frames A more realistic and, hence, nonlinear analysis of reinforced concrete structures is becoming increasingly important. A combination of the displacement method, the transfer matrix method, and a cross section module is suggested which leads to an effective analysis method for general reinforced and prestressed concrete frames. The combined method considers both material and geometrical nonlinearities including large deformations. The first level computation of the system is incrementally and iteratively carried out by the displacement method. At element level, an extended transfer matrix method is used for determining both the internal forces at the element end nodes and the stiffness matrix. The transfer matrix method is recursively applied to the deformed element, which is discretized into individual segments whose number and lengths depend on the stiffness gradient. The cross section module is based on cross-sectional integration. It takes into account nonlinear material behavior including cracking, softening, and yielding of reinforcement. [source]