Optimization is a process through which the best possible values of design variables are achieved under the given of constraints and in accordance to a selected optimization objective function. Steel I-girders have been used widely in different fields, which are generally fabricated by connecting two plate flanges, a flat web and a series of longitudinal or transverse stiffeners together. The use of steel girder with external prestressing has been used in many countries as a means of strengthening bridges. The purpose of this paper is to develop a finite element model for the optimization of a steel girder with external prestressing. The ANSYS finite element software package was used to find the optimum cross section dimension for the steel girder. Two objective functions are considered in this study there are optimization of the strain energy and total volume of the girder. The design variables are the width of top flange, the thickness of top flange, the width of bottom flange, the thickness of bottom flange, the height of the web, the width of the web and area of prestressing tendons. Two type of steel girder are considered there are steel girder without prestressing and steel girder with prestressing.The results for volume minimization shows that the optimum cross section for steel girder with prestressing smaller than for steel girder without prestressing.

The objective of structural design is to select member sizes with the optimal proportioning of the overall structural geometry. Conventional steel I-beam with variable depth have been used widely in various engineering fields. The objective of this study is to develop a three-dimensional finite element model for the total volume of steel I-beam with variable depth. The finite element software package ANSYS was used to determine the optimum total volume for the steel I-beam with variable depth. The purpose of the study is to minimize the total volume of the steel beam. The design variables are the height of the steel beam at support, the flanges width, the thickness of flanges, the height of the steel beam at mid-span, and the web thickness. The constraints considered in this study are the normal stress in steel beam and the mid-span displacement of the steel beam. Optimization results of steel beam indicate that the total volume was reduced approximately by 52 %.

The most commonly used test method for measuring the bond strength between reinforcing bars and concrete is the pull-out test of pulling a reinforcing bar out of a concrete block. During serviceability and durability design the bond of reinforcing bars is important in crack control. This paper presents numerical model for studying the size effect on pull-out force. This research considers three bar size diameter, which is 10, 12 and 16 mm bar diameter. The finite element ANSYS software was used for the numerical analysis. The specimens are analyzed until the specimens failure were occurred. The analytical results indicate that the pull-out force increase with increasing bar diameter. The pullout force for specimens S12 and S16 are increase (7% and 35%) compared with specimen S10 respectively.

There have been great developments in the area of civil engineering in the recent few decades and among these, construction and material innovation are quite prominent. Steel-concrete composite construction has emerged as one of the fastest methods of construction. Even though considerable research efforts on conventional reinforced concrete columns have been executed prior to now, concrete filled steel tube (CFST) composite columns however have received limited attention. This work aims to study the experimental behavior of steel tubular specimens. Plastic and steel specimens are considered with circular and square sections filled with the concrete with the steel fiber and as well, plain concrete. Four parameters are considered in this study which are sectional designs (circular and square), tube thickness (2 and 5 mm), tube material (plastic and steel) and content of steel fiber (0 and 5%). Ten concrete filled steel tubular columns were cast and tested. Two circular columns were made from plastic and the other made from steel. The main purpose of this work are study the effect of steel fiber and cross section on the ultimate load capacity of columns. It was discovered the utilization of steel fiber reinforced concrete filled steel tubular columns have comparatively substantial stiffness in comparison with plain concrete filled columns.

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