مؤيد عدنان عبد شحاثة

Scaling and similitude large scale structural member to small scale model is considered the most important matter for the experimental tests because of the difficulty in controlling, lack of capacities and expenses, furthermore that most of MSc and PhD students suffering from choosing the suitable specimen before starting their experimental study. The current study adopts to take large scale slab with opening as a case study of structural member where the slab is squared with central squared opening, the boundary condition is fixed from all sides, the load represents by four concentrated force in four corners of opening, as well as, the study adopts Buckingham theorem which has been used for scaling, all the parameters of the problem have been formed in dimensionless groups, the main groups have been connected by a relations, those relations are represented by force, maximum stress and maximum displacement. Finite element method by ANSYS R18.1 has been used for analyzing and forming relations for the large scale member. Prediction analysis has been computed for three small scale models by depending on the formed relations of the large scale member. It is found that Buckingham theorem is considered suitable way for creating relations among the parameters for any structural problem then making similitude and scaling the large scale members to small scale members. Finally, verification between the prediction and theoretical results has been done, it is observed that the maximum deviation between them is not more than 2.4%.

Rehabilitation, upgrading, or strengthening of structural members, especially columns, has become the target of many researchers because columns are the most important members in a building and the failure of columns causes direct collapse in the building. This study aims to get an assessment of the best pattern of steelframed jacket used for strengthening axially loaded concrete columns by numerically studying the behavior of the column for different cases of the same amount of steel jacket. The jacket consists of four angles and/or battens, lacings, or battens with lacings. The nonlinear analysis program designated as ARCC-SSJ (Analysis of Reinforced Concrete Columns Strengthened by Steel Jacket) is used to compare different patterns with the same and different cross-sections of battens and single lacing, as well as battens and lacing with battens taken into account. It is found that lacing with battens is the best pattern for the same amount of steel jacket with different cross-sectional areas. It is observed that the load-carrying capacity of the column increased by approximately 1.8 and 1.15% over that of battens alone in the case of a lacing angle of 60.832 ∘ and 74.407 ∘ with the vertical axis of the column, respectively.

In this study, the behavior of cambered reactive powder concrete slabs under impact loads was experimentally and analytically investigated. The results have been compared with other stiffened slabs in order to find the most resistant and economic slabs. The parameters that have been taken into consideration represented by studying the effect of slab cambering, thickness of slab, steel fibers ratio, steel strip stiffeners and ordinary steel reinforcement

The research has prepared programmed mathematical techniques by Visual basic language for analysis, design and calculating the optimization of precast prestress hollow core slab panels. The research deals with the optimization by adopting the modified Hooke-Jeevs method which is considered as a very suitable method especially for problems have as many constraints. The formalizing of objective function was discussed according to required purpose. The aim of the study is to discuss three parameters (optimum weight, optimum cost and optimum live load). It is found that the average void percentage ratio regarding the optimum weight is about (50%) whereby the section tends to be in a shape where the voids become less than thickness and width ,as well as, it is found that the average of void percentage ratio concerning with the optimum cost is about (41%) . The research also adopted preparing designable tables which are informative and easy in use practically for different kind of hollow core slab sections, it is found from the prepared maximum live load tables that the deflection restricts the span length not less than (60%), furthermore that adding topping slab (5cm) thickness increase the span length about (16-20) % for thicknesses (15-22) cm.

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