Recursos de colección

Caltech Authors (169.428 recursos)

Repository of works by Caltech published authors.

Group = Earthquake Engineering Research Laboratory

Mostrando recursos 1 - 8 de 8

  1. WeighCam: a New Electro-Optical System

    Taghavi Larigani, Shervin; Heaton, Thomas H.
    [no abstract]

  2. Performance of Viscous Damping in Inelastic Seismic Analysis of Moment-Frame Buildings

    Hall, John
    This report investigates the performance of several viscous damping formulations in the inelastic seismic response of moment-frame buildings. The evaluation employs a detailed model of a 20-story steel building. Damping schemes included in the study are Rayleigh, condensed Rayleigh, Wilson-Penzien, two versions of tangent Rayleigh and one implementation of capped damping. Caughey damping is found not to be computationally viable. Differences among the damping schemes, as quantified by amounts of plastic hinge rotations and story drifts, become noticeable once these quantities reach the 3% level. In order of least to greatest hinge rotations and drifts that occur under lateral response...

  3. Can we measure deformation of short and stiff bridges when a train passes over using a camera?

    Taghavi Larigani, Shervin; Heaton, Thomas H.
    [no abstract]

  4. Can you measure the weight of a truck with a commercial camera?

    Taghavi Larigani, Shervin; Heaton, Thomas H.
    [No abstract]

  5. Modal coupling and earthquake response of tall buildings

    Hoerner, John Brent
    The major dynamic features of tall buildings are within the scope of a shear beam model. Herein the usual one-dimensional model is extended to three dimensions to include modes with translational and rotational components. The analysis is restricted to the continuous model with linear response. A class of models for tall buildings is presented which possesses three sets of mutually orthogonal coupled modes. The amount of modal coupling is related to the eccentricities divided by the translational-torsional frequency differences. Strong modal coupling can occur if the eccentricities and frequency differences are small, as in a rectangular building with a smooth distribution...

  6. Dynamic Analysis of Coupled Shear Walls and Sandwich Beams

    Skattum, Knut Sverre
    A study is made of the free vibration of planar coupled shear walls, a common lateral load-resisting configuration in building construction where two walls are coupled together by a system of discrete spandrel beams. The differential equations and boundary conditions are obtained by the variational method, and by assuming that the spandrels can be replaced by a continuous system of laminae, or small beams. Natural frequencies and mode shapes are determined, and the results are presented in a number of figures from which the natural frequencies of any coupled shear wall can be extracted. The importance of including vertical displacement in...

  7. Semi-Active Control of Dynamically Excited Structures Using Active Interaction Control

    Zhang, Yunfeng
    This thesis presents a family of semi-active control algorithms termed Active Interaction Control (AIC) used for response control of dynamically excited structures. The AIC approach has been developed as a semi﷓active means of protecting building structures against large earthquakes. The AIC algorithms include the Active Interface Damping (AID), Optimal Connection Strategy (OCS), and newly developed Tuned Interaction Damping (TID) algorithms. All of the AIC algorithms are founded upon the same basic instantaneous optimal control strategy that involves minimization of an energy﷓based performance index at every time instant. A typical AIC system consists of a primary structure targeted for vibration control, a...

  8. Seismic response of steel frame buildings to near-source ground motions

    Hall, John F.
    Strong near-source ground motions contain large, rapid displacement pulses that can have severe effects on structures. In the U.S. it is generally agreed that our design codes do not adequately address this kind of ground motion, and changes are being made to increase the design force levels, which will result in stronger buildings. In Japan, the design force levels for buildings have for some time been considerably greater than in the U.S. Even so, Japanese engineers are also concerned about the adequacy of their design provisions for strong near-source ground motions. The issue of building strength appropriate for near-source ground motions...

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