H Ghasemzadeh, ,
Volume 5, Issue 2 (4-2012)
Abstract
In this paper, using Mononobe & Okabe method, seismic force and its effects on thin masonry retaining wall inside structural frame (Masonry retaining infill) are presented. In this method, retaining wall has been assumed to be rigid and the prevailing failure mode is sliding of wall bed joint or wall rotation around its toe, whereas the prevailing failure mode of masonry retaining infill is usually flexural cracking in middle zone of wall under out of plane seismic force. In this case, the seismic force distribution is important. Accordingly in this paper, a distribution for seismic forces on masonry retaining infill has been proposed. Also with regard to out of plane behavior of masonry retaining infill in terms of strength and acceptance criteria aspect, failure in body of wall due to out of plane loads has been analyzed. Then, the desired seismic rehabilitation method in case of vulnerable masonry retaining infills has been presented and as a practical example, results of the proposed method with the results of numerical software have been controlled. Finally, according to various conditions predicted for masonry retaining infills, Seismic Retrofit solutions are presented for practical applications.
Prof. Seyed Amirodin Sadrnejad, Dr. Hasan Ghasemzadeh, Mr. Ahmadali Khodaei Ardabili,
Volume 12, Issue 5 (English article specials 2018)
Abstract
In a perforated well, fluids enter the wellbore through arrays of perforation tunnels. These perforations are typically distributed in a helical pattern around the wellbore. Available numerical models to simulate production flow into cased-and-perforated vertical wells have complicated boundary conditions or suffer from high computational costs. This paper presents a simple and at the same time efficient finite element model to simulate flow around a well with helically symmetric perforations. In the proposed model, by taking advantage of the symmetry, only a thickness of perforated interval containing a single perforation tunnel needs to be meshed. Angular phasing between adjacent perforations is considered by applying periodic boundary conditions on the upper and lower boundaries of the representative reservoir thickness. These boundary conditions involve periodic-pressure and periodic-velocity parts. Unlike the periodic-pressure part, the method of imposing the periodic-velocity condition within a single-variable flow problem is rather vague. In this regard, it is proved that in the proposed model, periodic-velocity condition is automatically satisfied in a weak sense. The accuracy and the computational efficiency of the proposed model are verified through comparison with available models. The model results, in terms of skin factor, are compared with the common semi-analytical model as well, and good agreement is obtained. The proposed model can readily be used as a numerical tool to study inflow of wells with helically symmetric perforations.
