It is well-known that the behavior of soil-structure systems can be well described using a limited number of no ndimensional parameters. This is the outcome of researches based on the premise that the foundation is bonded to the ground. Here, it is shown the concept can be extended to systems with foundation uplift. A set of non-dimensional parameters are introduced which controls the main features of uplifting systems. The effect of foundation uplift on response of soil-structure systems are investigated parametrically through time history analysis for a wide range of systems subjected to ground motions recorded on different soil types. In particular, the effects of uplift on displacement ratio, defined as the ratio of maximum displacement of the uplifting system to that of the elastic system without uplifting and drift ratio, defined as the ratio of maximum drift of the structure as a part of uplifting soil-structure system to that of the elastic system without uplifting, are investigated. It is observed that in general foundation uplift reduces the drift response of structures, which in turn, results in lower base shear. The reduction reaches about 35 percent for slender structures located on relatively soft soils subjected to strong ground motions. Simplified expressions are suggested to estimate this reduction in the base shear.

The effect of the uplift force in the hydraulics structures is against stability. So, determining and controlling this force can be very important. One of the ways to achieve this purpose is to decrease this force by using the hole drains; in this way, we can build perpendicular pipes with different diameters, leading to the durability of the structure. Therefore, an experimental model of concrete dam was constructed in the hydraulic laboratory. The dam's model was divided into five sections by using 4-hole drains with a thickness equal to the dam's foundation. By running experiments with the maximum water level at the upstream, dam hole drains were opened in their position. Hydraulic potential was estimated by using the Piezometer built in the flume body. Finally, by opening some hole drains, the uplift force was calculated from the equipotential lines. Therefore, the best case (which had the minimum force) was determined, which was a/L=0. 4, to create the most proper hole drain in the dam foundation. (a: distance of drain to heel and L: length of the dam's foundation). To place the hole drain in this position, by applying the zero potential in this position, the up lift force was increased

Seepage flow modeling beneath hydraulic structures on permeable materials is an essential issue that must be considered before construction processes. Because of no detailed studies, followed by inappropriate design some problems such as foundation erosion, seepage and water escape and structure settlement may be occurring. If we couldn’t overcome these problems in designing process, we can utilize a series of auxiliary actions. Some actions for eliminating the piping and reducing the uplift pressure and hydraulic gradient are construction of horizontal apron, cut-off walls and also weep holes. Hence, in this study the effect of the weep hole on uplift pressure and hydraulic gradient has been investigated. For this purpose, the governing equation of flow through porous media has been solved for different setups, by the numerical method of Control Volume. All calculations have been done by the simple and powerful Excel Spreadsheet tools. Results show that, the application of weep hole reduces the uplift pressure and hydraulic gradient. Installation of a weep hole on stilling basin could reduce the cut-off wall depth and this cause a noticeable reduction of project costs. By moving weep hole toward the downstream of stilling basin and getting away from dam toe, its positive impact will be reduced.

In this research the simultaneous effects of foundation uplift and nonlinear behavior of soil are investigated. Previous studies have showed that the effects of soil-structure interaction on seismic performance can be described through introducing a limited number of non-dimensional parameters. In most studies it was assumed that the foundation is bonded to the soil and the behavior of the soil was considered to be linear or equivalent linear. In this study it is showed that this concept can be extended to the nonlinear soil-structure systems by introducing number of new non-dimensional parameters. The main goal of this investigation is to study the variations of nonlinear displacement and ductility of nonlinear soil-structure systems. To achieve this goal, the structure is considered as a nonlinear single degree of freedom with concentrated mass which mounted on rigid foundation rested on distributed dampers and springs. Then the variations of the response of nonlinear soil-structure systems are assessed by conducting nonlinear time history analyses for a wide range of non-dimensional parameters. It is shown that the total displacement of soil-structure systems increases because of nonlinear soil behavior but the ductility of the structure as a part of soil-structure system decreases in comparison to the systems with linear soil behavior. So in this study, it is proposed to decrease the safety factor for the design of foundation. Since the permanent settlement of foundation is an important index in performance of soil-structure systems, therefore it was calculated for some applicable systems and it is shown that although the permanent settlement of the foundation increases by decreasing safety factor of foundation but the value of permanent settlement is acceptable for ordinary systems.

Joints, which are usually located in the abutments of dams, play a vital role in the seismic stability evaluation of arch dams. This paper presents a comprehensive numerical investigation of the influence of uplift pressure in joints on the seismic response of an arch dam, with a focus on the interaction between the dam and the rock wedges. For this study, the Bakhtiari arch dam, having one rock wedge at each abutment, was chosen as a case study, and three distinct finite element models of the dam were developed. Three components of El Centro were applied to the dam's foundation, and the influences of dam-rock wedge interaction on the crest displacement time history and tensile damage of the arch dam were investigated. Four different scenarios were taken into account. The results indicated that taking uplift pressure in joints into account has important effects on the dam responses

Uplift Modeling aims to detect subgroups in a population with a specific response or reaction to an action taken on the targeted group. In these models, the Treatment set contains objects that have been exposed to some action, such as a marketing campaign or clinical treatment, while in the Control set, they have not. In this study, a novel artificial immune system-based model was designed using an AIRS classifier to solve uplift modeling problems with improved efficiency. In this approach, a predictive model was built for estimating the conditional probability of receiving the desired response from the subpopulation that has taken the action over the relevant probability of the sub-population that has not taken the action. The proposed model was tested on the Hillstorm-visit-w dataset. Experimental results showed a 138 percent improvement in the area under the uplift curve which is a measure to assess an uplift model's performance.

The purpose of present paper is to develop the 2D NASIR software for analyzing pore pressure in homogeneous and isotropic foundation of dams with cutoff walls and its verification and application. This software uses Galerkin- Finite volume method to model seepage and solution of its governing equations in foundation of concrete gravity dams. The accuracy of developed model is evaluated by comparison of its results with analytical solutions of uplift pressure under concrete gravity dams with upstream cutoff wall. After verification of the numerical solver results, the computational tool is used to evaluate the accuracy of simplified relations which are suggested for calculating uplift pressure on homogeneous isotropic dam foundations.

Many analytical methods proposed for solving two-dimensional problems of groundwater are concerned with functions which transform the problem from a geometric status, where solution must be found, to another status in which the solutions are known. Conformal mapping and its appropriate techniques allow us to change complex flow problems into regular geometric shapes. Throughout the present paper, an analytical solution is provided for estimating uplift pressure in alluvial foundations below dams. In the present study, velocity Hodograph and Schwartz -Christoffel integrals are employed to determine the uplift pressure in alluvial foundations within different depths and sizes of sheet pile and upstream blanket. An important point in this study is the asymmetric insertion of blanket relative to sheet pile along the longitudinal path. Finally, the results obtained through this method us the ones of laboratory methods were compared to assess the accuracy of analytical results and to critically discuss the strengths vs weaknesses. The results indicate that in some cases new analytical method underestimates uplift pressure while in some circumstances there exists a good agreement between the two.