Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : soil

Lateral Seismic Response of Building Frames Under the Influence of Soil–Structure Interaction

Mohammed Ahmed Elaiwi; Ghzwan Ghanim Jumah

Engineering and Technology Journal, 2016, Volume 34, Issue 3, Pages 567-577

This study deal with the elastic and inelastic structural responses of building frames under the influence of soil–structure interaction. Three give the types of moment-resisting building frames, including 5 storey, 10-storey and 15-storey buildings are selected. In addition, three soil types with the shear wave velocities less than 600m/s, representing soil classes Ce, De and Ee according to IBC-2006(3) , having three bedrock depths of 10m, 20m and 30m are adopted.
The structural sections are designed after conducting nonlinear time history analysis, on the basis of both elastic method and inelastic procedure considering elastic-perfectly plastic behavior of structural elements. The frame sections are modeled and analyzed, employing finite difference method adopting ANSYS software under two different boundary conditions: (a) fixed base (no soil–structure interaction) and (b) considering soil–structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted. The results in terms of the maximum lateral displacements and base shears for the above mentioned boundary conditions for both elastic and inelastic behaviors of the structural models are obtained and compared, with the results. A comprehensive empirical relationship is proposed to determine the lateral displacements of the moment-resisting building frames under earthquake and the influence of soil– structure interaction.

Optimization of the Time Required for Determination of the Total Dissolved Salts in Soil

Mohammed Y. Fattah; Maysam Th. Al-Hadidi; Baqer A. Ali

Engineering and Technology Journal, 2014, Volume 32, Issue 13, Pages 3272-3283

The purpose of this paper is to determine the shorter time required for proper determination of the total dissolved salts in soil. The usual test takes 3 to 4 days to measure the total dissolved salts in the sample. Eighteen samples were gathered from different sites in Baghdad city. The physical properties were determined experimentally. The testing program was done by two stages; the first stage included measurement of ordinary T.D.S (series A) while the other stages included measurement of the magnitude of total dissolved salts at different times.
It was found that after 24 hours of soaking the soil in distilled water, the total dissolved salts will reach about 95 % of the actual amount (after 3 days). The usual procedure takes at lest three to four days which is very long time if there is no time or conductivity device. Therefore, a proposed procedure is submitted to estimate the T.D.S. after 24 hours which revealed very good agreement with the actual values. The results of T.D.S. measured after 24 hour give a suitable compatibility with those measured by the ordinary method after 3 days where the coefficient of determination R2 equals (0.918). An expression was determined which can be used to estimate the T.D.S. from values measured after 24 hours only.

Numerical Simulation of the Infinite Medium of Dry Soil in Dynamic Soil-Structure Interaction Problems

Saad Faik Abbas Al-Wakel

Engineering and Technology Journal, 2013, Volume 31, Issue 8, Pages 1447-1458

One of the major issues in the dynamic analysis of soil-structure interaction problems is to model the far field medium. The dynamic analysis of soil-structure interaction problems can be carried out by using a numerical solution procedure such as finite element method. For domains of infinite extension of the soil, using of the standard finite elements method leads to spurious reflections for waves on the artificial boundaries which can seriously affect the results.
This research presents a method based on the mathematical representation of wave propagation to analyze the problems in dynamic soil-structure interaction. In this method, the infinite medium (unbounded domain) of the soil is represented by viscous elements to simulate the radiation damping in the soil. In addition, the material damping of soil is represented by Rayleigh damping and implemented in the bounded domain.
The results obtained from this study indicated that, dissipation in the energy of wave occur due to representing of the infinite medium of the soil by viscous elements and Rayleigh damping. By comparing the results with those obtained from the boundary elements method to simulate the infinite extension of the soil which is proposed by Estorff and Kausel (1989), a good agreement is achieved. In addition, the dynamic response at any depth under the foundation can be estimated by using the present method.

2D-Flow Analysis Through Zoned Earth Dam Using Finite Element Approach

Hayder Hassan Al.Jairry

Engineering and Technology Journal, 2010, Volume 28, Issue 21, Pages 6315-6324

This paper presents an application of finite element analysis using
CivilFEM/ANSYS(11) software to predict two dimensional steady state water seepage through an earth dam of two soil zones resting on impervious base. Seepage characteristics (quantity and length of seepage surface) produced at downstream are investigated against permeability coefficient ratio changing of the two soil zones, and based on results of the solution it was found that seepage quantity and velocity downstream are very sensitive to any change of permeability
ratio of the two soil zones forming the dam.