Porosity is one of the key parameters associated with oil reservoirs. Determination of this petrophysical parameter is an essential step in reservoir characterization. Among different linear and nonlinear prediction tools such as multi-regression and polynomial curve fitting, artificial neural network has gained the attention of researchers over the past years. In the present study, two-dimensi...

the nonlinear static procedures (nsps) proposed by design codes do not lead to reliable results especially for tall buildings. they generally provide inconsistent estimates of inelastic seismic demands, especially for the top floors due to their inabilities in considering the higher modes effects. in this paper, a new enhanced pushover procedure is proposed which is based on the envelope of the...

Due to low stiffness of braces after yielding, the structures with buckling-restrained braces (BRBs) experience high residual drifts during an earthquake, which can be intensified by aftershocks and causes considerable damages to structures. Also, due to poor distribution of stiffness, this problem is exacerbated for irregular structures. Recently, the yielding brace system (YBS) has been intro...

Seismic reflector interfaces in the subsurface are typically idealized as zero-order discontinuities. According to this model, the Earth’s subsurface is represented by a spiky reflection coefficient sequence for which deconvolution methods have been derived. However, multiscale analysis on sedimentary basins reveals the existence of accumulation of varying-order singularities in the subsurface....

Two modeling techniques for practical nonlinear static analysis are implemented to support the development and usage of a new Limit Design method for special reinforced masonry shear walls. The new seismic design alternative is under consideration for future versions of the building code requirements for masonry structures in the U.S. The proposed simplified models were applied to a planar one-...

Based on the parallel computing cluster platform of the ABAQUS software, a large-scale 2D finite-element refined nonlinear modeling approach was used to study seismic site effects in the Fuzhou basin, such as peak ground acceleration (PGA), spectral acceleration, duration, and acceleration transfer functions. A 1D equivalent linear wave propagation analysis was conducted also, with Proshake for...

The work presented herein sets out to investigate numerically, by means of nonlinear finite element analysis, the effect of un-reinforced concrete or masonry infill walls on the overall structural response of reinforced concrete frames under static monotonic and seismic loading. For this purpose, a nonlinear finite element package purpose built for the analysis of concrete structures is employe...

Performance based seismic design (PBSD) is a cogent design approach that allows engineers to design structures with a predictable seismic performance for a specified level of hazard. In contrast to the conventional limit state or strength and serviceability based design in which a structure is designed to withstand severe load combinations and be functional under normal load conditions, PBSD go...

Seismic anisotropy is an efficient way to investigate the deformation field within the upper mantle. In the framework of rigid tectonic plates, we make use of recent tomographic models of azimuthal anisotropy for deriving the best rotation pole of the Pacific plate in the uppermost 200km of the mantle. It is found to be in good agreement with current plate motion (NUVEL1, HS3 and NNR). However,...

This paper reports on the damage of Wushi bridge in a recent Taiwan 921 earthquake. Damage to Wushi bridge appeared in the superstructure, the substructure and the approaches. Typical types of damage are discussed and illustrated in this paper. A review of the bridge design specifications in Taiwan is also presented to give the background on the seismic design of Taiwan highway bridges.