A Study of Seepage through Oba Dam Using Finite Element Method

Dams are constructed to impound water for flood control, water supply, irrigation, energy generation, recreation as well as pollution control. Yet destructive effects of water on them are enormous. Seepage has been implicated as a major cause of dam failure due to its potential to cause internal eruption of soil. Different methods have been identified to study the extent of seepage in earth dams.  Of the methods, flow net is commonly used due to its relative simplicity. However, it becomes more complex with zoned earthfill dams.  In this paper, Finite Element Method (FEM) is employed to study seepage behaviour in Oba dam. Though the method was developed for the analysis of aircraft structural problems, due to its versatility, it is found as tool to solve variety of other practical problems. Finite Element formulation of the governing equation was established and computer programme was written to solve it. The bottom of the dam was meshed using rectangular element mesh while the piezometric heads at nodal points were determined. Also, determine was the coordinates that define the phreatic surface of the seepage. The results obtained were compared with those obtained from flow net approach which served as control using t-Test technique. It was observed that there was no significant difference (p > 0.0005) between the results. Thus, the method is appropriate for the study. The added advantage of the FEM is that simulation of the seepage problem of the dam becomes easy. Keywords: Finite Element, seepage, Oba dam, piezometric head, phreatic surface

OPTIMIZATION OF DOUBLY REINFORCED BEAM DESIGN USING SIMULATED ANNEALING

The optimization of the doubly reinforced concrete beam was investigated in this paper using the simulated annealing. Materials costs are considered as the objective function. The variables are the width, depth, compression steel, tension steel and cost. The constraints are the ultimate moment of resistance, compression/tension-steel ratio, minimum and maximum area of reinforcements. At the concrete compressive strength of 25 MPa, it is demonstrated that simulated annealing method can be used to optimize the design of concrete beams

OPTIMIZATION OF DOUBLY REINFORCED BEAM DESIGN USING SIMULATED ANNEALING

The optimization of the doubly reinforced concrete beam was investigated in this paper using the simulated annealing. Materials costs are considered as the objective function. The variables are the width, depth, compression steel, tension steel and cost. The constraints are the ultimate moment of resistance, compression/tension-steel ratio, minimum and maximum area of reinforcements. At the concrete compressive strength of 25 MPa, it is demonstrated that simulated annealing method can be used to optimize the design of concrete beams

OPTIMIZATION OF SINGLY REINFORCED BEAM DESIGN USING SIMULATED ANNEALING

This paper investigated the optimization of a singly reinforced concrete beam using the simulated annealing. The enhancement of minimum cost of structures and the adoption of the algorithm method of simulated annealing were projected in resolving the complications of constraints associated with optimization problems. The variables are the width, depth, compression steel, tension steel, and cost. The constraints are steel ratios, ultimate moment of resistance, maximum and minimum area of reinforcements while materials costs are considered as the objective function. It is demonstrated that using the concrete compressive strength of 25MPa, simulated annealing can be used to optimize the design of concrete beams effectively. The results also indicate that the complications connected to the actual and genuine evaluation of costs of structures and the connectivity with the compulsory restraints can be adequately resolved using this method

Characterization of Bitumen Extracted from used Asphalt Pavement

The objectives of the research were principally to characterize extracted bitumen from Used Asphalt Pavement (UAP) on twelve selected roads through the determination of engineering properties (penetration and viscosity) and establishment of appropriate mathematical relationship between principal parameters of the extracted bitumen. Laboratory tests were carried out on three samples from each of the roads in order to obtain extracted bitumen characteristics.  Established equations and regression analysis were used to study and compare the behaviour of the extracted bitumen with existing national standards. The extracted bitumen from the mix was 5.00 – 6.40 %, which fell within the 5.00 – 8.00 % range specified.  Weak correlations existed between the actual age of the road and bitumen content with coefficients of determination of 8E-05 to 0.0943 for linear, exponential, logarithmic, quadratic, and fourth order polynomial.  The effect of the age of the road on the penetration and viscosity of the binder respectively indicated fair relationship with coefficients of determination ranging from 0.5361 to 0.6351.  The study showed that extracted bitumen may be reused for asphalt concrete pavement needed for road construction leading to preservation of environment and reduction in land filling.                                                                                                                                                           Keywords: Used asphalt pavement, Road construction, Extracted Bitumen, Coefficient of Determinatio

OPTIMIZATION OF DOUBLY REINFORCED BEAM DESIGN USING SIMULATED ANNEALING

The optimization of the doubly reinforced concrete beam was investigated in this paper using the simulated annealing. Materials costs are considered as the objective function. The variables are the width, depth, compression steel, tension steel and cost. The constraints are the ultimate moment of resistance, compression/tension-steel ratio, minimum and maximum area of reinforcements. At the concrete compressive strength of 25 MPa, it is demonstrated that simulated annealing method can be used to optimize the design of concrete beams