The assessment of a rock’s behaviour around excavations and the effectiveness of its reinforcement in underground ore mines is dependent on the performance of the rock-bolt and rock-mass interaction, which can be estimated on the basis of appropriately designed measurements. Based on the background of various measurements solutions described in the literature, concerning rock bolt monitoring methods, the authors proposed a new, original device for mass measurements in mine conditions. After examining the advantages and disadvantages of existing constructions, the article presents the essence, principle of operation and method of measuring anchor load in an underground excavation with the a instrument, indicator WK-2/8. The prototype has been carefully researched and successfully tested in a full-scale laboratory environment. This instrument, also referred to as a load indicator or force pad, does not require electrical power and allows for relatively accurate (with a resolution of 10-14kN, up to about 90kN loading capacity) and a remote reading of the axle loading of the anchor (AGH patent) by any person present in the specified area. The device can be installed in mining excavations under loading conditions. The relatively low cost of a measuring instrument, practically used as an additional washer, as well as an easy assembly method, makes it universally applicable in mines where anchoring is used as a means of strengthening the rock.
The aim of this study is to find the cost design of RC tension with varying conditions using the Artificial Neural Network. Design constraints were used to cover all reliable design parameters, such as limiting cross sectional dimensions and; their reinforcement ratio and even the beahviour of optimally designed sections. The design of the RC tension members were made using Indian and European standard specifications which were discussed. The designed tension members according to both codes satisfy the strength and serviceability criteria. While no literature is available on the optimal design of RC tension members, the cross-sectional dimensions of the tension membersfor different grades of concrete and steel, and area of formwork are considered as the variables in the present optimum design model. A design example is explained and the results are presented. It is concluded that the proposed optimum design model yields rational, reliable, and practical designs.
The research paper presents the results of the dynamic analysis of an existing bar dome subjected to wind loads. The calculation model of the structure was constructed using the finite element method. The dome was subjected to the standard wind pressure, assuming that it is operates in a harmonic manner. The numerical analyses were performed with the application of Autodesk Robot and MES3D. The analysis focused on the impact of selected factors such as the frequency of forcing, wind gustiness coefficient and structural damping on the behaviour of structures.
The objective of this paper is to present a probabilistic method of analyzing the combinations of snow and wind loads using meteorological data and to determine their combination factors. Calculations are based on data measured at twelve Polish meteorological stations operated by the Institute for Meteorology and Water Management. Data provided are from the years 1966 - 2010. Five combinations of snow load and 10-minute mean wind velocity pressure have been considered. Gumbel probability distribution has been used to fit the empirical distributions of the data. As a result, the interdependence between wind velocity pressure and snow load on the ground for a return period of 50 years has been provided, and the values of the combination factors for snow loads and wind actions are proposed.