Uniform Settlement Research Articles

Tests on a two-layered ballast system

Considerable evidence suggests that ballast is the main cause of uniform and non-uniform settlement of railway track, provided the subgrade is adequately specified. Over a period of time uneven settlement of the ballast will cause voids to form under the sleepers, leading to unacceptable ride quality of the track. Regular maintenance is required to keep the track geometry within acceptable limits and to maintain ride quality. The proposed two-layered ballast system described in this paper would replace the crib ballast by stone of smaller size. The aim is to fill the voids beneath the sleepers as soon as they become unacceptably large and thus to maintain ride quality without the use of tamping or stone-blowing. Preliminary model tests carried out on the system indicate good potential for it. The results of the model tests have been validated by full-scale tests in the laboratory. The tests have shown that by replacing crib ballast by stone of smaller size a void beneath the sleeper will be filled up to less than the void size minus the average particle size of crib ballast. The next logical step is to go for full-scale live track trials, and it is anticipated that these will take place in the near future.

Risk assessment of an interacting structure–soil system due to liquefaction

The present study deals with the non-linear stochastic dynamic analysis of a soil–structure interacting system. The ultimate objective is to determine the risk of damage to the system due to liquefaction under a wide range of earthquake intensities. A Monte Carlo simulation approach is followed in conjunction with advanced finite element procedures. The stochastic spatial variability of soil properties and the randomness of the seismic excitation are taken into account in order to estimate the statistics of the response, measured in terms of uniform foundation settlement and tilting. Specifically, soil properties are modelled as non-Gaussian random fields and seismic excitations as non-stationary random processes. The probabilistic characteristics of the stochastic field modelling soil properties are established from in situ tests. The risk of damage to the soil–structure system due to liquefaction is assessed by establishing fragility curves, which are of paramount importance for risk assessment and management studies of such systems. Fragility curves express the probability of exceeding various thresholds in the response. The relative effect of the variability of various soil parameters on the variability of the response is also examined. Copyright © 2002 John Wiley & Sons, Ltd.

Risk assessment of an interacting structure–soil system due to liquefaction

AbstractThe present study deals with the non‐linear stochastic dynamic analysis of a soil–structure interacting system. The ultimate objective is to determine the risk of damage to the system due to liquefaction under a wide range of earthquake intensities. A Monte Carlo simulation approach is followed in conjunction with advanced finite element procedures. The stochastic spatial variability of soil properties and the randomness of the seismic excitation are taken into account in order to estimate the statistics of the response, measured in terms of uniform foundation settlement and tilting. Specifically, soil properties are modelled as non‐Gaussian random fields and seismic excitations as non‐stationary random processes. The probabilistic characteristics of the stochastic field modelling soil properties are established from in situ tests. The risk of damage to the soil–structure system due to liquefaction is assessed by establishing fragility curves, which are of paramount importance for risk assessment and management studies of such systems. Fragility curves express the probability of exceeding various thresholds in the response. The relative effect of the variability of various soil parameters on the variability of the response is also examined. Copyright © 2002 John Wiley & Sons, Ltd.

Regulation and International Telecommunications Pricing Behaviour

Recent technology change and market liberalization have substantially reduced the costs of providing international message telephone services (IMTS). However, the full extent of these cost reductions have generally not been reflected in lower prices. This paper reviews the recent literature on international telecommunications markets, and examines regulation and IMTS pricing behaviour. Particular attention is given to the accounting rate system (ARS), uniform settlement policies, and asymmetric competition. Several market behaviour scenarios are described where regulation has resulted in carriers implementing inefficient pricing rules for both accounting and collection rates. Finally, economic and political strategies are put forward that could supplant the current outmoded and uneconomic ARS, and bring about the full benefits of a freely functioning marketplace to telecommunications users.

On the required connection strength of geosynthetically reinforced walls

The use of geosynthetics for the reinforcement of retaining walls, bridge abutments, and wing walls has progressed rapidly over the past 10 years. Design of the reinforcement, along with the requisite testing, has also advanced in a parallel manner. There is, however, an issue that has been raised over the required connection strength of the reinforcement to the wall facing. Theoretically it is felt, and shown numerically herein, that the required force is very small. Essentially all known wall systems can mobilize such forces. What is of concern is a number of short- and long-term issues during and after the wall is constructed which can possibly add to the theoretically required connection strength. They are individually described herein. Furthermore, they are grouped into three types of stress mobilizing situations: uniform settlement, localized asymmetric deformation and localized symmetric deformation. A parametric evaluation of each situation is offered illustrating the possible magnitude of increase of connection stresses beyond the theoretical value under a hypothetical set of conditions. While the values can become high, all scenarios can (and should) be avoided. Clearly, there should be no pressing concern over connection strength with proper design followed by proper construction practice.

Control of foundation shape and loading parameters to preserve uniform settlement

The problem of providing settlement uniformity of a rigid foundation on a non-uniformly compressible base has been reduced to the contact problem from elasticity theory, with controlling parameters which allow one to select either co-ordinates of the point of application of the vertical load resultant or contours in plan at which the foundation slope will be equal to zero. The solution of the problem is illustrated by numerical examples.

The pricing of international telecommunications services by monopoly operators

International telecommunications operators usually set their own tariffs, but traditionally reimburse one another at a uniform settlement rate. We identify profit maximising tariffs where settlement rates are initially allowed to differ. We then explore Nash bargaining over settlement rates. We show that only under circumstances which are unlikely to occur in practice will two monopoly operators agree on a system of common settlement rates. However, we show that one operator in collusion with its regulatory authority always has an incentive to insist on uniform settlement rates as a precondition for negotiation.

Foundation of a 157 m high transmission tower : J. Farkas & L. Marczal, Periodica Polytechnica: Civil Engineering, 38(1), 1994, pp 29–40

In a city of Hungary known to have a weak subsoil, a microwave transmission tower 157 m high, with a cylindrical reinforced concrete shaft was built. In its design, possibilities of both spread foundation and deep foundation arose. Beyond dead and live loads, also other effects (wind load, seismic effects, uniform and nonuniform settlement, daily and seasonal temperature variations) had to be reckoned with. In case of spread footing, that should be 25-30 m diameter because of the extreme height, uneven settlement and tilting, rather than soil failure, were the main problems. Effects likely to cause eccentricity like wind load and building inaccuracies had to be analyzed. In case of a deep foundation, which is technically much better, the point of the large-diameter bored piles was suggested to be taken in a clay beginning at 25 m below the ground level, which is in a much better condition than the overlying one. At last. the tower was built on spread foundation. During and after construction, stresses under the slab footing were recorded, horizontal and vertical displacements of the tower observed.

ON THE STUDY OF SETTLEMENT SYSTEMS BY MATHEMATICAL METHODS

Two Soviet regional planners test several spatial interaction models with particular reference to the Kuznetsk Basin (Kemerovo Oblast), the southern belt of West Siberia and a portion of the North Caucasus (Krasnodar Kray). Existing techniques, such as gravity and potential models, are found to work well in areas with relatively uniform settlement patterns, such as the steppe zone of Krasnodar Kray or the southern Ob'-Irtysh subregion of West Siberia, but not in areas with sharp contrasts in settlement patterns, such as the Kuznetsk Basin, where a linear highly urbanized belt is enclosed between sparsely populated mountains. In such contrasting settings, a combination of methods is required.

Settlement experiments with zoospores ofEnteromorpha intestinalis(L.) link

A method for obtaining uniform settlement of zoospores of Enteromorpha intestinalis is described. Using this method the optimum temperature for settlement on glass lies between 20 and 25° C, and the optimum salinity between 25 and 30‰. Light exerts a considerable influence on the initial rate of settlement but is not essential.

Report of the Committee on Uniform Settlement Laws and the Transfer of Dependents

Previous articleNext article No AccessProceedings of the American Association of Public Welfare OfficialsReport of the Committee on Uniform Settlement Laws and the Transfer of DependentsFrank W. GoodhueFrank W. Goodhue Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Social Service Review Volume 5, Number 3Sep., 1931 Article DOIhttps://doi.org/10.1086/630926 Views: 1Total views on this site PDF download Crossref reports no articles citing this article.