IMPROVING SEISMIC RESISTANCE OF HYDRAULIC STRUCTURES USING SOIL IMPROVEMENT TECHNIQUES
Most of the Egyptian irrigation structures were built many decades ago. Most of these structures may be classified as unsafe structures when making an assessment of their resistance to earthquake loads in accordance with the current specifications. This research suggests a technique to increase the ability of these structures to resist seismic loads. The suggested technique depends on using soil improvement methods to improve the most stressed soil bulb zone under the structure. The effect of seismic site soil factor will be decreased by improving this part of soil. Controlled soil jet grouting technique could be used for the existing structures. Other types of soil improvement techniques such as soil mixing could be used for new structures or other types of earth structures. Numerical study was performed to investigate the feasibility of the suggested method. Experimental study was carried out to validate the numerical study. The dynamic responses of an improved location and normal location were measured. The two locations were subjected to the same excitation force. The measured responses were compared and evaluated. Based on the results of the suggested technique, a real site condition for an existing barrage structure was numerically analyzed before and after soil improvement to examine the suggested technique.
Increase in Shear Modulus by Soil Mix and Jet Grout Methods
Abstract The results of in-situ geophysical cross-hole tests on improved soil by soil mixing (SM) and jet grouting (JG) are described. This testing was conducted on soil improved by SM and JG columns constructed in the downstream free-field of Tuttle Creek Dam near Manhattan, Kansas as part of the seismic retrofit. Results of similar geophysical testing performed on untreated soil in the vicinity of the Downstream Test Program (DTP) area, as well as beneath the embankment at several locations, are also described and used for comparison purposes. In-situ shear moduli are also compared with those determined in laboratory resonant column tests. The increase in stress wave velocities and associated shear moduli by SM and JG treatment are presented for use in liquefaction potential and seismic deformation analyses of SM or JG treated soil. This data is required to determine the decrease in liquefaction potential and earthquake-induced permanent deformations due to SM or JG with respect to that of untreated soil.
Colleagues as Change Agents: How Department Networks and Opinion Leaders Influence Teaching at a Single Research University
This study investigates colleague–colleague relationships within life sciences departments and how they may promote teaching reform. The authors found that discipline-based education researchers are perceived as promoting changes among colleagues in views about teaching and teaching practices. Other faculty may also be leveraged to support change.