Determination Of Load Carrying Capacity Research Articles

Modelling of Closed Steel Supports for Underground and Mining Works

The closed steel supports of different shapes are used in mining and underground constructions. The yielding and unyielding supports are prefabricated from rolled, usually robust steel profiles. The load carrying capacity of the support is considerably influenced by the active loading and passive forces. The passive forces are induced by the interactions of support with the surrounding rock massif [1]. The user-friendly software was processed for the operational determination of load carrying capacity. The analysis has three parts: the first part consists of the structural geometry processing. The second part includes the numerical solution of statically indeterminate structure for the specified load. The third part is the calculation of load carrying capacity, components of internal forces and deformations. The force method and the numerical integration were used for solution. The Winkler model is applied when the support is in interaction with the surrounding environment. The load carrying capacity of support is limited by the slip resistance of the connected parts and reaching the ultimate state of the profile. The plasticity calculation is performed in accordance with EN 1993-1-1 Ed. 2. The limit values beyond the scope of this standard can be selected for an alternative computation.

Determination of Load-Carrying Capacity of Railway Concrete Bridges According to New Guideline

The handbook "Determination of load-carrying capacity of railway bridges" [1] has grown up due to updating of old Slovak guideline [2] taking into account Eurocodes. In the case of railway bridges, there are about 2300 bridges in Slovakia and about 78 % of them are from concrete or masonry. About 28 % of bridge total number is older than 77 years and about 18 % of them are even older than 100 years. Therefore, there is need to make regular inspections, recalculate them – determine of load-carrying capacity and then to decide, which of them should be repaired or reconstructed [3,4]. The paper presents general concepts and basic assumptions for determining the load-carrying capacity of reinforced and prestressed concrete railway bridges. In contrast to design of a new bridge, additional data related to existing bridge condition and its behaviour like information from regular inspections and real state of degradation can be taken into account. Special recommendation and allowances for global analysis of existing concrete superstructures for the purpose of the load-carrying capacity estimation are discussed, as well.

A new Design Concept for Point Fixed Glazing

The determination of load carrying capacity and serviceability of point fixed glazing is a challenging task. A lot of parameters have an influence on the resulting values, especially on stress values around the bore hole. Generally, only specialized engineers are able to perform this analysis. Reasons for this are the multitude of parameters, the lack of analytical solutions and incompletely analyzed load carrying mechanisms on the one hand, and on the other hand, the lack of a generally accepted and accurate design concept for stress and deflection calculation in Germany. The calculation of point fixed glazing is usually done by using finite element analysis (FEA). However, the scatter of the results is very large – which means that the quality can be evaluated as low. The reasons for these deviations are usually based on the deficient FEA software and an inaccurate modeling done by the user. Therefore, the user needs a guideline for the design process. A new design concept for point fixed glazing has been developed on the basis of analytical, experimental and numerical studies. This new concept consists of two main parts. The first part is a quality check of the calculation model. The user has to prove his model by reference values and theoretical principles. The second part deals with the actual calculation process of the whole glazing. This process has to be done as case-specific analysis. Thereby, it contributes to a safe and realistic design process in the field of point fixed glazing.

Determination of Load-Carrying Capacity of Railway Steel and Concrete Composite Bridges

In the frame of global European standardization and in consequence of new knowledge related to existing bridges, the need for revision of the service handbook "Determination of load-carrying capacity of railway bridges" grown up. The paper presents general concepts and basic assumptions for determining the railway bridge load-carrying capacity. In contrast to design of a new bridge, additional data related to existing bridge condition and behavior like information from regular inspections and real state of degradation can be taken into account. Based on these data together with the remaining lifetime, a modification of reliability levels for existing bridges based on the mathematic theory of probability can be adopted in the evaluation process. Special attention is also paid to the specific features of determination of load caring capacity of steel-concrete composite bridges in exploitation. Recommendation and allowances for global analysis of existing composite steel and concrete superstructures for the purpose of the load-carrying capacity estimation are discussed as well.

A parametric method for preliminary determination of underwater vehicles deadweight

A parametric method for preliminary determination of underwater vehicles deadweightThis paper describes a method useful for determination of load carrying capacity of underwater vehicle, elaborated on the basis of investigations of series of vehicles of systematically changed geometrical dimensions. By using the set of the series of vehicles their structural mass and displacement - at a given structural material and assumed maximum permissible submersion depth - were determined, and next - approximation formulae for deadweight of vehicles were obtained. Vehicle's form may be consisted of one or a few cylindrical floats of circular cross-section, ended with caps. The floats are joined together with a space pipe frame. Acceptability of design solutions results from comparison of working stress values in float's shell plating with permissible stresses as well as critical stresses. The presented method may be useful in the preliminary stage of designing the underwater vehicles - i.e. may serve for preliminary determination of a vehicle deadweight - at its given, or determined, geometrical dimensions, maximum permissible submersion depth, as well as a selected structural material.

Determination of load-carrying capacity in panels with chevron-type cores

In this paper, the problem on creation of a mathematical model describing the behavior of a sandwich panel with chevron-type cores is considered. The model is meant for calculating the ultimate shearing compressive loads and its parameters are determined by the identification methods on the basis of experimental data.

Psychophysical determination of load carrying capacity for a 1-h work period by Chinese males

This study used the psychophysical approach to examine the effects of container width, the presence or absence of container handles, and different load-carrying frequencies and distances on the maximum acceptable weight carried and the resulting response (heart rate and rating of perceived exertion) by well-conditioned males for a 1-h work period. After training, 12 male subjects performed a load-carrying task at knuckle height. Each subject performed 30 different carrying combinations. The conditions examined were container width, from 15.2 to 55.9 cm; carrying frequency, from 1 carry to 5 carries/min; and carrying distance from 1 to 6 m. The results were compared with prior studies and led to the following conclusions: (1) the use of container handles leads to the subjects carrying a significantly higher maximum acceptable weight than when containers do not have handles, which differs from the results of a previous study by Morrissey and Liou (1988); (2) there were significant reductions in the maximum acceptable carrying weight with increases in container width, frequency and distance; (3) the presence or absence of container handles, different frequencies and load-carrying distances had significant effects on heart rate, although the effect of container width was not significant. In addition, the various frequencies and distances for load carrying had significant interaction effects on heart rate; (4) the effects of various frequencies and load-carrying distances on the rating of perceived exertion were statistically significant. The most stressed body parts were the wrists and arms.

Theoretical Analysis of Externally Pressurized Air Journal Bearing

A theoretical investigation is made to predict the performance of an externally pressurized air journal bearing having several pressure sources. The pressure distribution, which leads to the determination of load-carrying capacity and flow requirement, is obtained by solving Reynolds equation numerically. The load and flow, expressed in non-dimensional parameters, are presented for different bearing design parameters (dimensionless). The results predicted by this method are compared with others' experimental data.