Identification and modeling of earthquake ground response - I. Site amplification

Seismic downhole-array data provide a unique source of information on actual soil (and overall site) behavior over a wide range of loading conditions that are not readily covered by in-situ or laboratory experimentation procedures. In this paper, free-field downhole-array seismic records are employed to identify and model the recorded response at the Lotung (Taiwan) and Treasure Island (California) sites. At Lotung, a five-accelerometer array recorded the site response during 18 earthquakes (1985–1986). The Treasure Island site was instrumented in 1992 with an array of six accelerometers that recorded a low amplitude earthquake in 1993. Using this downhole data, correlation and spectral analyses are performed to evaluate shear wave propagation characteristics, variation of shear wave velocity with depth and site resonant frequencies and model configurations. In addition, the actual seismic shear stress-strain histories are directly evaluated from the recorded downhole accelerations. These histories provide valuable insight into the mechanisms of site amplification, damping and pore-pressure build-up. Computational simulations of these case histories are performed based on the identified mechanisms of site response. In a companion paper, two additional case histories of site liquefaction are analyzed using records of downhole seismic response.     

Bootstrap aggregating approach to short-term load forecasting using meteorological parameters for demand side management in the North-Eastern Region of India

Theoretical and Applied Climatology - Electricity is an essential commodity that must be generated in response to demand. Hydroelectric power plants, fossil fuels, nuclear energy, and wind energy...     

Dynamic behaviour and seismic response of El Infiernillo dam

El Infiernillo, a 145 m high rockfill dam in Mexico built in a narrow V-shaped canyon, was subjected to eight major earthquakes since its construction. In this study, the dynamic dam response is analysed using (i) the recorded November 15, 1975 bedrock-crest acceleration histories and (ii) the results of a 1970 full-scale test conducted by UNAM, in which eight upstream–downstream and longitudinal resonant frequencies and configurations were observed and documented. These observed and seismically induced dynamic responses are compared herein to predictions of two different numerical models of El Infiernillo dam; a newly developed simplified three-dimensional (3D) model, and a 3D finite element model. The dynamic dam response characteristics are assessed, and performance of the employed numerical models is evaluated. It is found that (i) higher modes of vibration had participated significantly in the recorded seismic response and (ii) upstream–downstream response is well represented by the two numerical models employed. Using the simplified model, the September 19, 1985 earthquake non-linear response is computed and shown to compare satisfactorily with its recorded counterpart in the upstream-downstream and vertical directions. The largest computed dynamic accelerations, stresses and strains are found to occur within the upper third of the dam body.     

A class of inhomogeneous shear models for seismic analysis of landfills

An analytical/numerical procedure is developed to calculate the shear elasto-plastic earthquake response of hill-shaped landfills. Landfill response is evaluated on the basis of newly developed one-dimensional inhomogeneous shear beam models. In these models, the nonhomogeneity of landfill materials is taken into account by assuming a specific variation of stiffness properties along the depth. Closed-form analytical expressions are derived for natural frequencies, modal displacements, modal participation factors, absolute accelerations and maximum shear strains. Parametric results are presented in graphical and tabular form and conclusions are drawn. Within a numerical implementation framework of the above formulation, the landfill materials may be modeled by an elasto-plastic hysteretic model following the principles of flow or incremental plasticity. The entire numerical procedure may be executed on a personal computer and consequently qualifies as a versatile tool for conducting preliminary design calculations or parametric-type investigations. Using this newly developed procedure, the seismic response of the Fresh Kills landfill in New York City is investigated.