For architectural or environmental reasons, openings sometimes are required inbearing block masonry walls. These openings which may have any size or location surelyaffect the mechanical behavior of such walls since they create some sort of stressconcentration around the corners. The existence of openings in bearing block masonrywalls does not only cause a change in the structural behavior but also reduces both thecracking and ultimate loads.In this study the effect of existence of square and rectangular openings in bearingblock masonry walls on the behavior of such walls was studied numerically using thefinite element method. Forty eight different models were tested to study the effect of theinfluencing parameters such as the size and location of the openings, wall sides boundaryconditions, . and type of loading on the wall behavior. Also the effect of loss of supportwas investigated.Linear elastic fracture mechanics based on pre-finite element and photoelasticityresults was carried out in this study in order to check the reliability of using suchmethods for predicting the ultimate load capacity of concrete block masonry walls withopenings and to investigate the possible propagation of cracks around the openings. Atotal number of forty walls were tested using the finite element and fracture mechanicsmethods in which the opening shape and size, type of underlying soil and the sidesboundary condition were varied. Photoelasticity method was also used to -investigate thebehavior of nine bearing block masonry walls.popular methods are made. The method is then extended to allow thetracking of time-varying system parameters.An adaptive control structure based upon this Tracking-PLIDalgorithm is proposed which utilizes pole-placement state variablefeedback via Ackermann’s formula. The capabilities of this adaptivecontrol scheme are demonstrated by application to a full-order nonlinearaircraft simulation model where significant improvement is shown overfixed-gain controllers in the face of rapid plant changes.