Mechanical behaviour of concrete block masonry walls

The wide spread of the use of masonry structures resultedin the creation of different construction techniques inbuilding masonry walls The behaviour of concrete blockmasonry walls subjected to concentrated load is a commonlyencountered problem in practice for design of masonrystructures such as cross beams lintel supports, etc .The behaviour of solid masonry walls under a concentratedload was studied before , but the performance of hollow ,grouted and reinforced concrete masonry walls under the sametype of loading is still a matter of research .In this study , an experimental program was performed toinvestigate the effect of the different constituent materialsof concrete block masonry walls ( hollow , grouted andreinforced ) on the mechanical and deformational behavioursof these walls under a concentrated load . A total of twentyfour wall panels were used to study the effect of mortarstrength , grout strength and the steel reinforcement of thebond beam on the crack pattern and made of failure , crackingload , load - deflection relationship, and horizontal andvertical strain distribution .It was found that the increase in mortar strength ofhollow masonry walls resulted in an increase in the crackingand ultimate loads and in the stiffness of the walls , and areduction in the vertical and horizontal strains The sameeffect was noticed in grouted masonry walls , but only aslight change was recorded at high values of mortar strengthThe enhancement in the mechanical properties of groutedwalls due to the presence of grout columns was significant .However , the grout strength had no effect on the differentmechanical properties of the grouted walls . Reinforced wallsby both bond beam and vertical and horizontal reinforcementshowed higher capacity in resisting a concentrated load thanunreinforced ones Lastly the increase in the mainreinforcement of the bond beam lead to an increase in themechanical behaviour of these reinforced walls .In addition , a brief cost estimate of wall bearingstructures of concrete block masonry was introduced to make acomparison between its cost and the cost of the skel tonstructure types . it was found that the cost of the bearingwall type is equal about 90 % of cost for skelton structuretype .