In this paper, the bi-directional evolutionary structural optimization (BESO) method is used to find optimal layouts of 3D prestressed concrete beams. Considering the element sensitivity number as the design variable, the mathematical formulation of topology optimization is developed based on the ABAQUS finite element software package. The surface-to-surface contact with a small sliding between...

In this paper, a new approach for nonlinear numerical modelling of the reinforced concrete shear walls with consideration of bar-concrete interaction and shear deformation is proposed. Bar and concrete stress-strain relations, the bar-concrete interaction, the shear stress-strain relation and, also, their cyclic behavior including the strength degradation and stiffness degradation are adopted a...

The main objective of this study is to evaluate the workability of fresh portland cement concrete while it is still in the mixing truck by determining fundamental rheological parameters (plastic viscosity and yield stress). Nine concrete mixtures with different values of yield stress and plastic viscosity were tested in a concrete truck. The measurements made with the truck were based on the ty...

. This paper presents the results of an experimental investigation on shear strength enhancement of reinforced concrete deep beams externally reinforced with fiber reinforced polymer (FRP) composites. A total of six deep beam specimens of two different classes, as-built (unstrengthened) and retrofitted were tested in the experimental evaluation program. Two composite systems namely carbon/epoxy...

In this paper, a new roofing system is introduced, which is constructued using the precast composite sandwich panels. This roofing sandwich panels system consists of three kinds of precast concrete sandwich panels including capital panels, beam or between columns panels, and slab or middle panels. The panels are composed of three layers; A high strength reinforced concrete top layer. A thick la...

In this paper, a series of studies to reinforced concrete cracks have been done by image graying, calibrating, image denoising, image enhancement and image segmentation, and the binary image of cracks is finally obtained. Using the Box Method, the fractal dimension of cracks is determined. The relationships between the fractal dimension of surface cracks in the cracking beam under three-point l...

In concrete pavements, a single concrete mixture design is selected to resist mechanical loading without attempting to adversely affect the concrete pavement shrinkage, ride quality, or noise attenuation. An alternative approach is to design distinct layers within the concrete pavement surface which have specific functions thus achieving higher performance at a lower cost. The objective of this...

The assessment of response of composite seismic force resisting systems requires accurate nonlinear formulations for the composite members. In this work, reporting the first phase of a NEES project, a three-dimensional distributed plasticity formulation is presented for both circular and rectangular composite concrete-filled steel tubes (CFTs) that includes new constitutive models for the concr...

Cracks in concrete cannot be prevented but the size of cracks can controlled. that occur are strongly influenced by nature and characteristics constituent materials, especially cement water. fresh hard phases. grouped into two, non-structural structural cracks. There several types such as crazing, map cracking, plastic cracking due to shrinkage, settlement, drying temperature changes, chemical ...