Search

Abstract The stability of circular footings under eccentric vertical loads is a significant problem in geotechnical engineering. Therefore, this paper shows the results of experimental tests carried out on an eccentrically loaded circular foundation on sand soil. The focus of this research is on examining how eccentric loads affect the behavior of circular footings on sand soil, both with and without skirts. Various load eccentricities (e) equals zero, 2.50, 5.00, 7.50, 10.00, 12.50, 15.00, 17.50 and 20.00 mm are used. In addition to, a 60 mm-diameter circular foundation and sand with an 85% relative density (Dr) are used in this experimental study. To study the effect of changing the skirts depth on the load-settlement response skirts with different depths (h) = 60 mm, 150 mm, 240 mm are used for vertical reinforcement. In comparison to the unreinforced condition, test findings show an improvement in ultimate bearing capacity. When the skirts are positioned at the ideal embedment depth L/D = 4, it is found that the circular footing's load-settlement behavior is enhanced by 92% and 93% in case of using (e/D) ratio = 0.125 and 0.25 compared to the unreinforced case.

The appearance and development of new construction materials, technology and accurate geodetic instruments have led to the necessity of their inevitable use in the health monitoring, maintenance, and restoration of civil structures and special structures such as high-rise cooling towers. This paper presents an accurate practical and analytical method for determining the structural deformation and axis inclination of high rise cooling towers using terrestrial laser scanner (TLS) observations through the projection of tower surface points coordinates on a vertical plane. Four cooling towers in El-Mahla El-Kubra city, Egypt are observed and studied. Two of them with height 56 m, and the others were 36 m height. The studied four towers have different cross-section diameters along the tower height. Each tower has a cone shape with a curved wall. The equation of the tower wall is determined using TLS observations and least squares adjustment techniques. The equations of cone projection with a curved wall are derived and presented in this paper. From TLS observations, the radii and accuracy of each 2 m tower height are determined with center coordinates, and then the inclination of the tower axis is calculated and drawn. From the results of TLS observations, data processing, and analysis using the suggested techniques, it is deduced that there is a deformation in tower walls with small values. The specified technique for observations collection and TLS data analysis through projection on a vertical plane is significant and valuable for determining the structural deformation of circular high rise buildings and towers. From the results, there are obvious deformation values in some cooling towers, so maintenance work must be included. The towers also must be checked and monitored several times at brief intervals.

A new design of soil erosion and rainfall simulator is presented at this study as an attempt to deduce a mathematical formula of soil surface erosion phenomenon to describe the behavior of the sandy soil under the rainfall simulation, soil deformation such gullies and surface eroding rills are monitored by the Digital Close Range Photogrammetry (DCRP) technique that includes capturing digital images with a smart cellphone camera, and a Terrestrial Laser Scanner (TLS) to digitalize the soil surface as a smart point cloud data to produce Digital Elevation Models (DEM) with accuracy reaches 0.10 mm 3D surface model. The results show that the mentioned methods give typical digital surface feature express especially of using geometrical adjustment that controls the orientation of the digital surface, the digital imaging feature detection technology achieves accurate results despite its small cost compared to the laser scanner that the cost of imaging equipment and software are used did not exceed 12% of TLS cost. Results of the statistical observations, a 3 order polynomial mathematical formula was generated through the digital photogrammetry method that describes the sandy soil behavior under the rainfall simulation as a relation between the eroding rate and the duration through the different slopes.