INTERNATIONAL JOURNAL OF INDUSTRIAL ENGINEERING AND PRODUCTION MANAGEMENT (IJIE) (INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE) (PERSIAN)
Year:2000 | Volume:11 | Issue:(SUPPLEMENT CIVIL ENGINEERING)|Papers Count:14

The study of water waves in ocean regions and their coastlines, without considering the wave-current interaction effects is incorrect. In this paper, the wave-current interaction is investigated. Winds, explosions, ship motions and earthquakes are the main causes of water waves in the oceans. In the coastal zones, water waves interact with long shore currents.Analytical, numerical and experimental models are available for solution of the wave-current interaction problems. The numerical solution of the governing equations; is carried out in two phases, Viz. a 'wave phase' and a "current phase'. In the wave level calculation, the current field is known and the wave ray paths are determined through step by step integration of a set of differential equations. In each step of integration, the equation of the wave action conservation and wave number conservation are solved to determine wave height and wave number, respectively. In the current phase, the characteristics of waves are known, and the governing equations of the shallow water are solved by Galerkin finite element method and the current unknowns (velocity and depth) are determined. The calculations are initiated in a wave phase, where currents are neglected. The two-level iterative model is continued until the results are converged.Based on this method, two computer programs called "SWERM" and "CAFEM" are developed in FORTRAN 77. Several examples are studied and the results are presented.The results showed that, when the current has a positive component in the direction of wave propagation, the wave lenght increases and the wave height decreases. Conversely, a negative current component reduces the wave lenght and increases the wave height.Also, for current in the direction of wave, current velocity increases. The results are compared with cited results, and the accuray of results are checked.

Scouring caused by flow from an verflow spillway in a Plunge Pool has been studied. The effects of bed formation on the final depth of scouring is investigated.Tests were conducted for two different flow (namely 0 and 15 L/S), three different falling head (namely 45, 60, and 75 cm), ad four different bed materials (1, 2.75, 7.15, and 11 mm).Results obtained show that the relation provided by Kotulas for estimating the final scouring depth caused by falling jets in a plunge pool is more suitable. Based on statistical analysis a relation for estimating the scouring depth is presented.

In this study, unsteady flow through rectangular and trapezoidal cross sections is routed by a multi-linear Muskingum method. Flow surface profiles are calculated by solving the continuity differential equation using an implicit finite difference scheme. The reference discharge in every time step is computed by employing a nonlinear exponential function in terms of Mannings coefficient, bed slope, bed width, side wall slope and the peak discharge.The parameters are calculated by using a nonlinear optimization technique. Results of the developed model are compared to the MIKE 11 hydraulic model. The accord between the two is found to be satisfactory.

Structure of runoff. rainfall mathematical model comprises of separation base flow discharge and determining infiltration, effective rainfall and direct runoff. These processes are calculated by various methods. Instantaneous unit hydro graph which Nash model in its index sample has considered as a conceptual model, applied widely in runoff. Rainfall models. Here, the author produces a conceptual mathematical model with some proposed methods for determining separation processes of baseflow infiltration, effective rainfall runoff and direct runoff. Non. Linear mathematical optimization is used for calculation of the model's parameters. Performance results of the model prove the superiority of the proposed method over the other common ones. For doing the research, both methods of artificial neural networks and mathematical optimization of instataneous unit hydrograph are used, because the artificial neural network only, requires a lot of information and the results may not always be obtainable, but an artificial neural network. mathematical optimization combination makes possible a quick convergence and assured results.

A large deformation Lagrangian model is used to evaluate the cone penetration test in soil. The soil is assumed to be an elastic perfectly plastic material.The model is axismmetric and the cone and surrounding soil are assumed to interact through a cylindrical interface. The interface has a non-linear mohr – Coulomb constitutive behavior.Several numerical tests are performed. Cone penetration in clay and layered soils are studied and the importance of several parameters such as soil modulus, cohesion, friction and depth of penetration, on the cone factor, are examined. Finally, the numerical results are discussed and compared with those reported in the literature.

In this paper analysis and design of space rigid jointed frames are performed using artificial neural networks. Different nets are trained and tested for accuracy. A statistical study of results, considering the existing constraints, shows that a good approximation is obtained. These results are tabulated and included in the paper.

In usual nonlinear analysis of structures, only the effect of axial load 011 flexural strength is considered. However in practice, the interaction of bending moment, axial load and twisting moment occur in quite a few number of structural elements. This interaction cannot be neglected for members with low bending strength (Le. members with thin open section). In this study, using beam-column theory, the required equations for members force-deformation relations are developed, considering the interaction of axial load, bending and twisting moment. To obtain the equations, material is assumed to be elastic, but deformations could be arbitrarily large. Using the present method, numerical results are generated for different structures with thin open sections (e.g. angles, c-sections) and critical loads are evaluated. Based on the results obtained, it is concluded that the present method is an effective and accurate one.

This paper presents a new hypoelasticity constitutive relationship with the material axes rotating through successive iterations. The idealization is employed both fixed for crack and rotaing crack models, compressive strength degradation in the post-cracking regime, and a new uniaxial stress-strain relationships for plain and reinforced concrete under monotonically increasing loads, accounting for mesh sensitivity based on a strength formulation. This model was implenented in the non-linear finite element analysis program, results from detailed analysis of several R.C. shear panel tested by Vecchio and Collins (1981) in University of Toronto including various predicted strees-strain response at different stages of loading are presented.

During strong and destructive earthquakes, the effect of ground motion on structures is much higher than what is predicted by using equivalent static analysis based on elastic behavior assumption. The structural requirements in this case need to be studied using non-linear dynamic analysis.In this paper the behaviour of steel frames under strong ground motions is studied. Three types of frames with four, six, and eight stories which were either braced or non-braced were designed according to Iranian Standard (2800) and then analyzed subject to Tabas and Naghan earthquakes. As the ductility demands were found to be high, these accelerograms were also scaled to 0.35 g as PGA and the analyses were repeated. The effects of observing the strong column-weak beam principle on the levels of ductility demand were also studied.

One of the effects of tectonic forces on the ground formations is the formation of foldings and fractures such as joints and faults. The study of these fractures especially sedimental formation during and hereafter is the main object for many projects including oil well fields. Therefore, Their estmation, using ground surface topography determines fractures pattern in different areas of individual structure of geological structures. To do this, a number of engineering geology mapping from one of the important anticlines which is known as Mish anticline in the north of Gachsaran city has been carried out to study the relationship between joints system and strata on the goes around surface topography other than folding. So, the procedure could be used for investigations of fractures in the formations by using surface topography.

One of the most effective and economic methods for prevention of damages due to cavitation is flow aerating. Aerators are structures which are constructed on spillways for aerating pursposes. Mechanism of air-entraining to the water flow is qiute complex and for designing of aerators, physical model is usually used.In this paper, it is shown the contact angle of water jet to the spillway bed, has an important effect on aerating rate. Due to the high impoartance of physical models on the design of aeration, scaled errors are sdiscussed and a techniquebased on roughening of model in order to reducing the scaled errors is proposed.

In this paper, an efficient approach is presented for reduction of bandwidth for stiffness matrices of skeletal structures. after selecting two nodes with highest eccentricity employing a priority function nodal numbering is performed.This algorithm is efficient and requires small computer storage. For illustrating the efficiency, comparison is made with Cuthill-Mckee's method.

In this research, twelve cencrete mixtures have been made using three types of portland cement (type 1,2 and 5) and a slag blended portland designed for three initial compressive strengths of 20, 25 and 30 map. In total, 204, 15cm cube concrete samples have been made after 15, 30, 60, 120, 180, 210 and 240 minute rotation in mixer, for compressive strength tests. Slump tests of the mixtures together with compressive strength tests of the samples in 28 days of age were carried out. The test results indicate that delay in concreting increases the compressive strength and decteases the workability of concretes using four types of cement and three initial design strengths. Also the initial water/cement ratio of mixtures is found as an effective factor on concrete workability with respect to delay in concreting.