The finite element method is used to investigate the behavior of a strip footing constructed near the edge of a sloping cohesive ground. The effects of variation in footing closeness, loading eccentricity and slope angle are studied also. It is proved that Bowles method overestimates the load carrying capacity of the concentrically loaded strip footings on cohesive soils. Decreasing the distance between the footing and the slope edge, increasing the eccentricity and slope angle reduce the ultimate bearing capacity. Slope effect diminishes as the footing distance from the edge approaches (1.5) times its width.

The design of a soil improvement system, by preloading with wick drains, is formulated as a constrained optimization problem. The drain spacing, length, embankment height, and time required to achieve a specified consolidation settlement are selected as design variables whereas, the total cost of the system is adopted as an objective function. The cost function includes excavation, sand blanket, engineering fill, surcharge, wick drains, instrumentations and observation cost components. For a given site dimensions, soil profile, targeted settlement, and maximum allowed time to achieve, a computer program is coded in Fortran-90 to solve the problem of consolidation in vertical and radial directions based on Hansbo's (1981) and Olson (1977) methods, with different options to include the effects of smear, well resistance, ramp loading, and wick drains characteristics. In conjunction with the modified Hooke and Jeeves optimization method, the program is applied to a real project under construction in Basra province-Iraq. The real site dimensions, soil profile, and soil characteristics, as obtained from the site investigation program, are adopted. For the unit prices assigned, the results support the capability of the optimization method in manipulating such a decisionmaking problem. They also revealed failure of decision taken of canceling the inclusion of wick drains and adopting preloading only as a technique to improve the site soil. Studying the effects of the values of coefficients of consolidation in two directions on the behavior highlighted the vital importance of conducting a preliminary site investigation to evaluate foundation proposals. After arriving to a decision regarding soil improvement, the detailed phase of site investigation should be oriented towards finding the first order soil parameters associated with the selected soil improvement method, instead of wasting the efforts and money through conducting an exaggerated number of traditional less important tests. It is concluded that increasing the coefficient of consolidation in the vertical direction and the ratio of its radial value to the vertical one will increase the optimum drain spacing and decrease the drain length, the time required to achieve a specified settlement, and the required cost of the system. Embankment height, time of consolidation and total cost are proportional to the required settlement.

Multi-story hypothetical reinforced concrete buildings of variable geometric configurations (symmetrical, vertically irregular, horizontally irregular, with and without shear walls); with isolated bases via high damping rubber bearing and friction pendulum systems, are analyzed by using finite element method under seismic load function (North-South component of the ground motion recorded at a site in El Centro, California in 1940) via SAP2000-V16 software. Four methods of analysis are adopted. The accuracy of nonlinear modal time history is compared to that of methods recommended by international codes, namely; nonlinear direct integration, equivalent lateral force, and response spectrum methods. The bilinear hysteretic model of base isolation system and the Rayleigh damping framework for superstructure are adopted. The results support the powerfulness of the nonlinear modal time history analysis, due to the negligible deviations from those predicted by the robust nonlinear direct integration method. The response spectrum method proved to be more reliable than the equivalent lateral force method which over predicts the displacement and rotation profiles for the isolated buildings.

The seriousness of the phenomenon of negative skin friction on piles penetrating Basrah soil in Iraq is investigated via the finite element method. The most common (0.285×0.285 m) precast driven and (0.8 m diameter) bored piles, are analyzed under the structural loads and down drag forces due to recent fill. A two-dimensional program adopting nonlinear constitutive relations for soil layers is utilized. The results revealed a great decrease in negative skin stress and pile length on which the phenomenon is to act upon, due to the application of structural loads. Reductions in drag forces as much as (86%) for driven piles and (96%) for bored piles are recorded in some sites. It is also concluded that, overlooking the negative skin friction does not result in failure and that more economical pile capacities could be adopted.