During field observation of some existing structures it was noticed that the unsymmetrical arrangement of longitudna1 reinforcement about the vertical axis of R.C. beam cross section has become a human problem. This problem is caused either due to a human error or an initial imperfections especially in marginally engineered non supervised structures. f t may also occur as a result of steel bar tutting in one side during electric works. The objective of t.his paper is from one hand to study the behavior of such beams, from the other hand to declare and drawback these errors. Experimental work was done in the R.C. laboratory, civil engineering department, Assiut university. Fourteen of the specified r.c. beams were tested under two point static loading up to failure. The effect of localization of both bottom and top
reinforcement, quality of concrete, shear span to depth ratio as well- as the percentage of longitudinal reinforcement were studied. The cracking load, ultimate load, deflection and longitudinal strains were measured at mid span point on both
sides oi the beams. Also, the pattern of cracks and mode of failure were also included in this study. A new recommendations were given concerning the drawbacks of these errors and its significance in practice