The main objective of this research is to estimate the sizes of riprap (loose rock) on highway or railroad embankments approaching bridges, that would be stable in major floods. Two assumptions about the flow direction were made: one horizontal to the bridge abutment and the other normal to the projection of the bridge abutment. Three dynamic conditions of stability of riprap were observed and classified as shaking, some movement, and large movement (washing out). Shaking is the most conservative criteria for design because it indicates more stability than is necessary, requires larger rock, and is less cost efficient. Some movement suggests a conservative design criteria and is the most desirable because it requires smaller riprap and is therefore less expensive. Large movement or washing out means the least stable condition; it may leave the structure as well as human lives exposed to danger.

This thesis is an attempt to develop a theoretical microeconomic model which can be used to examine the short-run demand for the timeliness of farm machinery repairs. This analysis focuses on the timing of the repair after a breakdown has occurred. The nonstochastic model developed allows the incorporation of the timing of the repair as a variable input into a production function. A yield function (a function which gives the instantaneous rate of output in bushels per acre as a function of the date of harvest) is used in deriving this production function. From the production function a demand curve for the timeliness of repairs can be derived. A constrained input demand curve (CIDC) is used to examine the demand for timely repairs. A specific functional form of the yield function is used in order to allow an easier examination of how various parameters affect the CIDC. Several testable hypotheses which result from the model are presented. An attempted test of one of the hypotheses is discussed. / Graduation date: 1971

No description available.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. / The sudden failure of oil paper-insulated current transformers has become a problem of considerable concern due to the cost of the resulting destruction, and danger to personnel. The aim of the dissertation is. to determine the most suitable method of detecting lncipient faults in current transformers, test this method on an experimental current transformer, and finally implement this technique in a low cost on-line monitor. A literature survey indicated that hydrogen gas-in-oil on-line monitoring would be the most suitable technique.(Abbreviation abstract) / Andrew Chakane 2019

This research describes a proposed accelerated testing procedure for evaluating pavement patching materials under the simulation of traffic loading and environmental conditions such as freeze-thaw cycles. Potholes were constructed in concrete blocks with different tilt angles (13¢ª, 17¢ª and 22¢ª) to simulate normal and shear wheel surface stresses. Different patching materials, including hot mix, cold mix and commercial cold patch were tested. Various cyclic loads accompanied with cycles of freezing and thawing were applied to the patch. Patch performance is assessed by visual monitoring of the surface distresses and measuring surface elevation for rutting and shoving determination. Applied vertical loads varied between 2,250 and 4,500 pounds at a frequency of 2 Hz. Patch performance comparisons were made as a function of the patch mix, applied load, number of applied loads, frequency of loading, and applied freeze/thaw cycles. The new method of accelerated testing is successful in differentiating the performance of good and poor quality mixes. The proposed test could be used as a reliable method by state highway agencies for establishing acceptance criteria for selecting pothole patching mixtures.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis. 1977. M.C.P.--Massachusetts Institute of Technology. Dept. of Urban Studies and Planning. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / No leaf 124 ; 2 leaves numbered 128. / Bibliography : leaves 139-144. / by Ernest J. Ulibarri. / M.C.P.

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / Includes bibliographical references. / M.S.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Collapse and cracking of debris earth embankment dams is a serious problem in areas of the arid Western United States. The use of geogrids is evaluated in this thesis as a possible solution to prevent or reduce the amount of damage to the structures from collapse and cracking. An apparatus was designed, constructed, and instrumented to electronically acquire data to evaluate the behavior of geogrids during pullout tests under various normal stresses. The pullout tests were also modelled using numerical techniques to correlate physical test data with numerical test data. Understanding the behavior of the geogrid, in both the physical and numerical pullout tests, allowed the geogrid model to be combined with a collapsing dam model to evaluate the effectiveness of reinforcement at reducing, or preventing, damage caused by collapse and cracking. Results from this model indicate that the effectiveness of the geogrid was minimal. The ineffectiveness of the geogrids, however, may be a result of numerical modelling problems associated with the computer program.