Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 128-137). Also available in electronic format on the Internet.

Thesis (MScIng)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Retaining walls (RW) are among the most common geotechnical structures. They have been widely used in railways, bridges (e.g. bridges abutment), buildings, hydraulic and harbor engineering. Once built, the RW can be exposed to dynamic loads, such as those produced by earthquakes, machines, vehicles and explosions. They must remain operational in aftermath of the natural or human-induced dynamic events. Hence, the understanding of the geotechnical response of RW to these dynamic loads is critical for the safe design of several civil engineering structures such as railways, highways, bridges, and buildings. Although fairly reliable methods have been developed for assessing and predicting the response of RW to dynamic loads induced by earthquakes, there is very little information to guide engineers in the design of RW that are exposed to surface explosions (surface blast loadings). These methods for assessing RW response to earthquake loads cannot directly be applied to the design of RW subjected to surface blast loads. Indeed, blast loads are short duration dynamic loads and their durations are very much shorter than those of earthquakes. The predominant frequencies of a blast wave are usually 2-3 orders of magnitudes higher than those of earthquake wave, and the same can be said for blast wave acceleration as compared to the peak acceleration that results from an earthquake. Thus, RW response under blast loading could be significantly different from that under a loading with much longer duration such as an earthquake. There is a need to increase our understanding of the response of RW to surface explosion loadings since there is a significant increase of terrorist threat on important buildings and some lifeline infrastructures. Transportation structures (bridges, highway, and railway) are unquestionably being regarded as potential targets for terrorist attacks. The purpose of this PhD research is to investigate the geotechnical response of reinforced concrete retaining wall (RCRW) with sand as a backfill material to surface blast loads. The soil-RW model was subjected to a simulated blast load using a shock tube. The influence of the backfill relative density, backfill saturation, blast load intensity, and live load surcharge on the behaviour of RCRW with sand backfill was studied. The dimensions of the stem and heel of the retaining wall in this study were 650 mm (height) x 500 mm (width) x 60 mm (thickness) and 400 mm (width) x 500 mm (length) x 60 mm (thickness), respectively. Soil-RW model was placed inside a wooden box. The overall height of the box was 1565 mm. The retained backfill extended behind the wall for 1300 mm. Based on the results, it is found that the maximum dynamic earth pressures were recorded at a time greater than the positive phase duration regardless of the backfill condition. The total earth pressure distribution along the height of the wall showed that the magnitude of total earth pressure for loose and medium backfill at the mid-height of the wall slightly exceeded the dense backfill. In addition, the lateral earth pressures increased with the increase in the blast load intensities. On the other hand, under the same load conditions, an increase in the wall movement was noticed in loose backfill, and a translation response mode was evident in this condition. The mobilized passive resistance of the RW backfill induced by blast load was used to determine the force-displacement relationship. Finally, the susceptibility of the RW with saturated dense sand to liquefaction was examined, and it was ascertained that liquefaction was not triggered when the RW was subjected to a blast load of 50 kPa. The results and findings of this PhD research will provide valuable information that can be used to evaluate the vulnerability of transportation structures to surface blast events as well as to develop guidance for their design.

The subject of this thesis is the design of a local road cut off in the resort Hálův mlýn located in the cadastral of municipality Lažánky, Brno-venkov district, South Moravian Region. The thesis contains static calculation and design documentation.

Det senaste hundrafemtio åren har inflyttningen till städer och tätbebyggda områden ökat markant och genererat en glesbygd med väldigt liten befolkningsmängd. Detta har medfört försämrad samhällsservice med långa avstånd och försämrad kvalitet inom hälso- och sjukvård. Detta har också lett till svårigheter att rekrytera personal till glesbygd. Studien har som syfte att undersöka vilka motivations- och incitamentsfaktorer som är viktiga för att sjuksköterskestudenter ska kunna tänka sig att bo och arbeta i glesbygd. Data har samlats in med en enkät. Vårt resultat visar att anknytning och att vara bekväm i den sociala miljön är väldigt viktigt, men också att känna att man gör en skillnad för samhället. Vårt resultat bekräftar vad tidigare studier visat, nämligen att ett arbete på glesbygd skulle vara mer intressant om icke-monetära incitament fanns, till exempel större uppskattning från chefer och ledning samt vetskap om att kunna få stöttning i svåra situationer. Genom att utöka ett samarbete mellan utbildningsinstanser och framtida arbetsgivare skulle man öka medvetenheten hos studenter kring vilka karriärvägar och kompetensutveckling som finns på glesbygd, vilket vårt resultat också visar är incitamentfaktorer som önskas. Att ha praktik på glesbygd bygger en anknytning, där vårt resultat visar att de som haft praktik är mer positivt inställda till arbete på glesbygd. Resultatet visar också att väldigt få studenter har haft praktik på glesbygd. Skulle detta utökas skulle attityden kunna förbättras. Framtida forskning på ämnet är viktigt, vi hoppas att vi kunnat bana en ny väg genom att basera vår studie på en vedertagen teori om grundläggande mänskliga värderingar.

The purpose of this paper is to evaluate the performance of a Welded Wire Retaining Wall and present design recommendations for its future use. Field data from the instrumentation of a Welded Wire Retaining Wall as well as laboratory data from a study of welded wire fabric as a reinforcing agent for soil was gathered. A study of the theory and practice of reinforced soil construction was made. On the basis of this study and the experimental data obtained, the wall is evaluated and design recommendations presented.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Bibliography: leaves 140-141. / by Chin Pang Wong. / M.S.

Seismic pressures on displacing or rigid retaining or basement walls have been derived based on the original work of Mononobe and Okabe, who used a shake table to calculate dynamic pressures of displacing retaining walls existing in cohesionless soils. Since this original work was done over eighty years ago, the results of Mononobe and Okabe, colloquially known as M-O theory, have been applied to different conditions, including non-displacing basement walls, as well as changes in soil properties. Since the original work of M-O, there have been numerous studies completed to verify the accuracy of the original calculation, most notably the work of Seed and Whitman (1970), Wood (1973), Sitar (Various), and Ostadan (2005). This has resulted in varying opinions for the accuracy of M-O theory, whether it is grossly unconservative or conservative, as well as its effectiveness for situations where the wall does not displace enough to engage active soil conditions. This study examines (3) different wall cases, a cantilever retaining wall, gravity retaining wall, and rigid basement wall, through an implcit finite element analysis, under simple sinusoidal boundary accelerations. The soil is modeled using the Drucker-Prager model for elastic-plastic properties. The dynamic pressure increment is observed for different driving frequencies, with the anticipation that an in-phase and out of phase response between the soil and structure will be achieved, resulting in both lower and higher than M-O pressure values.

No description available.

No description available.