JOURNAL OF FACULTY OF ENGINEERING (UNIVERSITY OF TABRIZ)
Year:2004 | Volume:29 | Issue:3 (33) Civil Engineering|Papers Count:7

The purpose of this paper is based on two areas. The statistical analysis of ruptures of major high dams, obtained from extensive consultation of the technical literature is the main focus. It analyzes these accidents according to Frequency, causes, chronicle and geographic distribution; and the distribution depending on the age and type of dam. It proposes an evaluation of the hazards due to dam failure and examines the consequences of these accidents, such as number of victim. The second goal is to solve the equations governing one dimensional unsteady flow in a sloping channel. To this aim the governing equations on dimension less characteristics form has been transformed by choosing the convenient reference variables. Then the outcome has been solved analytically. The calculated solution for hydraulic quantities such as the positive and negative wave front evolution, the trace of the maximum heights, and the time height variation at a given downstream station are represented on applicable dimensionless plotting form, and compared with experimental data available in the technical literature. It is shown that the wave front celerities are sensitive to bed slope channel and are increased by increasing its values.

A finite element model is constructed to simulate the behavior of bolted-angle beam-to-column connections components. The material and geometric non-linearity and contact problem are considered in this model. For tracing nonlinear behavior of the component after slip, a simple slip-bearing model is proposed for contact between the bolt shank and hole. The comparison between computed values and laboratory test results permits the effectiveness and degree of accuracy of the proposed [mite element models to be evaluated. A parametric study was carried out to derive force-displacement relations for connections components.

In this paper, firstly, existing methods for determining the behaviour factor of moment-resisting steel frames and their range of applicability for multi-degrees of freedom frames are reviewed. Modifications of this factor for multi-degree of freedom moment-resisting steel frames are then indicated. Necessary modifications in determining the behaviour factor of frames involve the period and the base shear distribution factor for a given earthquake loading code. The effect of storeys, spans and connections of frames on behaviour factor were considered over range of values for these factors for frames up to three spans and eight storeys. Based on the results, new relationships for the period and the behaviour factor of moment-resisting steel frames are presented.

Considering effective parameters on load carrying capacity of CFT columns, in this study, a novel section is suggested which can be used for columns of tall buildings and bridges with large spans. The main characteristic of the suggested steel section is internal symmetric stiffeners. In the present study, 9 CFT columns, divided into two groups, have been considered for analysis under axial and cyclic loading. All of the analyses have -been undertaken using ANSYS. In order to verify the accuracy and validity of the finite element mode ling, the theoretical results, obtained nom material and geometric nonlinear static analyses, have been compared with the available experimental results of the CFT columns. It has been found that the finite element model is reliable enough to be used to undertake nonlinear analyses for comparative investigation. The results of this study clearly indicate the high strength and ductility of the suggested novel section under axial and cyclic loading and therefore, its application should be considered because of its appropriate behavior and better performance.

In order to consider flow structure in open channels, for a fully developed turbulent uniform flow, boundary shear stress and its distribution have been investigated. As the distribution of boundary shear stress around wetted perimeter and the effect of cross sectional shape are very important in sediment transport, so the boundary shear stress distribution have been evaluate4 and compared for different channel cross sections (i.e. rectangular, trapezoidal, circular and v-shaped bottom channels). The boundary shear stress was measured using a Preston tube having an outer diameter of 4.075mm. The experimental data illustrates that the lateral distribution of boundary shear stress shows that for mild slope channels, they are fairly flat, but that for the steep slope this is not the case. The analysis of results also shows that the channel cross-section and secondary flows are more effective on boundary shear stress distribution. Of course, this outcome is different for subcritical and super critical flow conditions. For this purpose, the percentage shear force carried by the walls (%SFw) has been used. The result shows that %SFw is favorably correlated with the geometry parameter, P+=Pb/Pw An interesting result is that the eddy viscosity coefficient is a function of flow rate, where the dimensionless eddy viscosity, l, decreases as the flow discharge increases. This matter should be applied in any computational models for open channel flows.

Cutting oils (emulsion O/W) are used to decrease friction and reduce heat in the metal industries. During use it can not be discharged to environment because of high pollution. The breakage of emulsion and separation aqueouse phase from organic phase decreases pollution in the aqueouse phase and permits to provide a biological treatment for it. The aqueouse phase presents the main volume of original influent. This paper describes the type of laboratory test for the treatment of this effluent by two methods, adsorption process and biological treatment .In adsorption process by activated carbon, the efficiency was 96% and after developing the experimental isotherm data by Freundlich and by Langmuir models, it was distinguished that Freundlich model is more adaptable to experimental data. In biological treatment, a fixed bed reactor in batch system was used. -In this process the efficiency was 80%.