Drilled shafts are cylindrical, cast-in-place concrete deep foundation elements. Their construction involves drilled excavation of soil or rock using large diameter augers, and placement of the necessary reinforcing steel in the excavation followed by concreting. Where a high water table is encountered, drilling slurry is used to support the excavation walls and concreting is tremie-placed. Even though the history of drilled shaft construction goes back to the 1950s, the occurrence of anomalies persists in the form of soil inclusions, reduction in shaft cross-sectional area and exposure of reinforcement. One of the main reasons for the anomalies is attributed to the kinematics of concrete flowing radially from within the reinforcing cage to the surrounding annulus/concrete cover region. In view of this radial component of concrete flow and thus radially flowing interfaces between the concrete and slurry, the region outside the cage is more likely to contain veins of poorly cemented or high water-cement ratio material. These veins contain trapped slurry, which oftentimes consists of bentonite, jeapordizing the integrity of the shafts. This research program focuses on the numerical evaluation of self-consolidating concrete (SCC) for drilled shaft application by taking into account realistic non-Newtonian concrete flow properties and the shaft structural blockages. For this objective, a 3-D computational fluid dynamics (CFD) model of the concrete flow in the shaft excavation is developed in ANSYS-Fluent. As a precursor to 3-D modeling, 2-D CFD modeling is carried out using COMSOL Multiphysics. In both 2-D and 3-D models, the Volume of Fluid method is used for computing the motion of the interface between the concrete and the drilling slurry. The models predict the flow patterns and volume fraction of concrete and slurry. The results are encouraging as the flow pattern from the simulation shows both horizontal and vertical creases in the concrete cover region. Moreover the flow pattern shows the concrete head differential developed between the inside and the outside the reinforcement cage. Further, the 3-D model is evaluated by studying the influence of the size of drilled shaft and arrangement of the bars and the results obtained are realistic. With this 3-D model developed as a tool, the simulation of SCC and the normal standard concrete (NC) flow in drilled shaft concreting are studied in terms of creases and concrete head differential encountered in the flow. From the simulation, it is observed that in the flow pattern of SCC, the creases are very few compared to the one obtained from the flow pattern of NC. Moreover, the concrete head differential in the flow pattern of SCC is much less, than the head differential obtained from the flow pattern of NC flow. In the case of SCC, the head differential encountered about one inch. In the case of NC, the concrete head differential is 4-inch when the vertical rebars are spaced at 7-inch apart and 10-inch when the rebars are placed at 3.5-inch apart. Based on this numerical evaluation of SCC flow in the drilled shaft excavation, it is concluded that the performance of SCC is better than the performance of NC in filling the cover annular region of drilled shafts.

Perceptual studies suggest that the visual system uses the "rigidity" assumption to recover three dimensional structures from motion. Ullman (1984) recently proposed a computational scheme, the incremental rigidity scheme, which uses the rigidity assumptions to recover the structure of rigid and non-rigid objects in motion. The scheme assumes the input to be discrete positions of elements in motion, under orthographic projection. We present formulations of Ullmans' method that use velocity information and perspective projection in the recovery of structure. Theoretical and computer analyses show that the velocity based formulations provide a rough estimate of structure quickly, but are not robust over an extended time period. The stable long term recovery of structure requires disparate views of moving objects. Our analysis raises interesting questions regarding the recovery of structure from motion in the human visual system.

The study area, which will be open to tourism in Kusadasi (Aydin), has steep and high cliffs near the Aegean coast. In the area where some slidings and rockfall problems occurred in the past the geological hazards should be investigated and nature-friendly remedial measures should be taken. The aim of this study is to perform engineering geological studies to:(i) search geological hazards, (ii) reveal the slope stability problems, (iii) recommend nature-friendly solutions in order to prevent/minimize the hazards and (iv)compare the results obtained from 2-D and 3-D rockfall analyses. To accomplish these tasks, the geological survey was performed, the information about the discontinuities was collected by means of scanline surveys, the rock samples were collected, the in-situ and laboratory tests were carried out, the slope stability and rockfall analyses were performed for different slope conditions, remedial measures were offered for the problematical areas considering the data obtained and the results of 2-D and 3-D analysis were compared. Under the light of these studies, rock removal, drainage, greening (vegetation), filling the caverns, wall building and erosion prevention were offered as remedial measures. The comparison of the 2-D and 3-D rockfall analyses shows that the end points and bounce height values are different for each method. The differences between the 2-D and 3-D model originate from the slope geometry, the algorithm used in the software and the different input parameters. According to the field observations, the 2-D model is more realistic than 3-D model.