SEISMIC EVALUTION OF CRACKED MASONRY BARRAGE PIERS REPAIRED WITH DIFFERENT METHODS

Abstract

The most common defects observed in masonry structures are cracking due to tensile stresses. Repairing process is needed to restore the structural capacity of the distressed masonry piers. Crack repair methods used in rehabilitation of water structures that have been built using clay bricks may affect the performance of those structures during their resistance to seismic loads. This research deals with evaluating the common methods used to repair major cracks of masonry piers. The evaluation process considered the performance of the repaired piers under the influence of seismic loads. Dynamic tests using shaking table with harmonic excitation were carried out to represent the effect of seismic loads. Therefore, the current paper investigates the dynamic structural performance of cracked masonry barrage piers, which are repaired using different techniques. Three different techniques are used for the purpose of repairing the cracked piers namely; epoxy pasted-repair, stapled using reinforced bars, and tied using pre-stressed technique. Four masonry piers were built on a shaking table and they were exposed to cyclic loads with different frequencies to simulate the earthquake. It was observed that the type of repair technique used affects the load carrying capacity of the piers and leads to a redistribution of the strains and hence stresses in repaired piers. All repair techniques are found to be able to restore or enhance the dynamic structural behavior for all the repaired piers that can stand against lateral loads with efficiency more than the uncracked pier. Guidelines for the assessment of the use of epoxy, reinforced and pre-stressed repair techniques in construction and strengthening of masonry barrages were suggested. For tied technique, some cautions must be considered when applied to overcome the base shear failure.