الفهرس 
Defects in soil or foundationOnly 14 pages are availabe for public view
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Abstract
As the using of reinforced concrete shells structures with opening have many advantages that they permit to cover large area without using intermediate supports and also decrease artificial light by using central opening. They have light weights and require minimum amounts of material that it is required small thicknesses comparing to their spans. In addition, their forms offer unlimited possibilities for architectural expression this investigation is carried out to study the efficiency of repair and strengthening of elliptical paraboloid reinforced concrete shells, which loaded by four concentrated load at the center of the opening. Constant dimensions for all samples are chosen to reduce the variables of the structural behavior. An experimental program of several different techniques in repair and strengthening executed. The material, which were considered for strengthening, are:
Glass fiber reinforced polymers GFRP, Steel strip and external tie. The tested shells were loaded by using hydraulic jack on steel frame. The initial crack load, the crack propagation for the tested shells at different loading stages, deflections and failure load for repaired and strengthened shells with opening were recorded. A non-linear computer program based on finite element techniques was used to study the behavior of this types of shells. Geometric and materials nonlinearities are considered in the analysis. The efficiency and accuracy of computer program were verified by comparing the program results with those obtained experimentally for the control shell with opening and strengthened shells.