Considerable research has been conducted in recent years on the behaviour of steel silos under loads generated by the contained materials and wind. A review is provided of the most important limit states and in each case relatively simple expressions are identified for determining the resistance of Ihe silo structure. Three important limit states of buckling under verticalload and wind load and buckling of ring beams are represented in design charts. Emphasis is placed on extracting appropriate models of behaviour for use in design from the vast amounl of research literature.
Guidelines for the geometric design of highways and streets are used to calculate minimum radii for horizontal curves and maximum curvature for vertical curves. Sight distance should always be greater than the stopping distance of vehicles. Current guidelines apply the stopping distance on a horizontal road to determine stopping sight distance, which results in an underestimation of the required radius or curve length on downgrades. A procedure is proposed that allows the engineer to take stopping distance on specific grades into account in road design.
Vertical flow of soil moisture, in situations with water application, drainage and evapo-transpiration, was investigated through theory in which the dynamic effects of both water and air were taken into account. The hydro-pneumatic properties of two model soils - a fine-grained loam and a medium-grained sand - were derived from publications by investigators worldwide. A system of equations for defining soil characteristics was descriptionbed, which can be applied to any soil tested in a specified manner. Lacking sophisticated laboratory service, complete data for a project soil, for which two specific readily determined properties are known, can be estimated from those of the model soils by interpolation. A method of analysis utilizing finite differencing was developed and its applications demonstrated by numerical examples in aquifer recharge and irrigation. The complex analytical problems arising from the hysteresis phenomenon in matrix potential, in situations where there is cyclic change in soil moisture content, were solved.