Examinando por Autor "Jaramillo J.D."

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    Base shear determination using response-spectrum modal analysis of multi-degree-of-freedom systems with soil–structure interaction
    (Springer Netherlands, 2019-01-01) Arias H.; Jaramillo J.D.; Mecánica Aplicada
    Building codes and design guidelines, e.g. FEMA (NEHRP recommended seismic provisions for new buildings and other structures, FEMA P-1050, Washington, 2015) and ASCE (Minimum design loads for buildings and other structures ASCE/SEI 7-10/2010, Reston, 2010), describe the problem of multi-degree-of-freedom systems with soil-structure interaction (SSI). These systems are modeled like those having a fundamental degree of freedom on a foundation with lateral and rotational interactions and the other vibration modes isolated and supported on a fixed foundation. This model oversimplifies the problem, neglecting the effects of having all modes coupled in the foundation with SSI. A simple, easily programmable, SSI model in which all vibration modes are coupled an attached to an infinitely rigid shallow foundation subjected to soil excitation is introduced here. Initially, the total response of the coupled system is calculated. Then, using traditional procedures to combine modal responses, a simplified alternative methodology to find the total response of this coupled system is proposed. The new methodology is verified against a robust numerical technique, i.e. boundary elements method, using a wide variety of cases that combine several types of soils, building heights and two structural typologies: bending frames and shear walls. Finally, it is clear from the parametric study that current methodologies, based only on the interaction of the fundamental mode of vibration of the structure, in some cases has a significant influence on the total base shear of buildings, particularly in tall buildings founded in soft soils. © 2019, Springer Nature B.V.
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    Influence of the uncertainty in the soil-rock spectral ratios in the definition of uniform hazard spectra at surface level
    (IMPERIAL COLLEGE PRESS, 2006-01-01) Jaramillo J.D.; Mecánica Aplicada
    Based on traditionally accepted hypothesis and verified by existing data, an expression is derived to calculate response spectrum at the ground surface if the response spectrum at the basement rock is known. The fundamental assumptions are with regards to the form of variation of the exceedance rates of spectral accelerations in the basement rock, and based also on the usual (lognormal) distribution forms of the uncertainties associated with the spectral amplification function. The resulting approach multiplies the mean of the amplification function in order to consider in a rigorous way its uncertainty. © Imperial College Press.
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    Investigación del colapso de un muro de mampostería de ladrillo no reforzado bajo fuerzas de viento moderado
    (Pontificia Universidad Católica de Chile, 2019-01-01) Aviram A.; Badillo J.W.; Prieto J.A.; Jaramillo J.D.; Mecánica Aplicada
    Several methodologies used for the collapse assessment of an unreinforced brick masonry wall subject to out-of-plane bending due to moderate wind loads in Medellin, Colombia are presented. Models include a rigid cantilever model of masonry elements, deformable cantilever and frame models of intermediate concrete columns and beams with and without masonry contribution to the wind resistance, and a finite element model with all concrete frame elements, masonry units and panel openings modeled explicitly. Wind demands are estimated using spatial interpolation of actual wind velocity measurements near the site. Results are presented in terms of peak deflections at the wall top, as well as peak force and stress demand-to-capacity ratios on concrete frames and masonry elements, respectively. Wind pressure distribution, P-Delta effects, interaction and relative contribution to the out-of-plane bending resistance of concrete framing and masonry elements with either one- or two-way action are shown to be the main parameters affecting results, in addition to model selection. Despite significant differences between models, recommended parameters and assumptions lead in all cases to the correct determination of the wall's imminent collapse under the estimated wind demands. © 2019 Potificia Universidad Catolica de Chile. All rights reserved.