Experimental studies on stocky masonry pillars strengthened with steel cords and PBO fibres

This paper presents a study of stocky masonry pillars strengthened by stainless steel cords and PBO fibres in bed joints. Ten physical models were used in experimental testing, of which 3 served as reference specimens and the remaining seven were confined in bed joints using different techniques. The pillars were constructed with lime mortar with parameters similar to those used in historical structures. To assure conditions similar to the real objects steel cords and PBO fibres were placed in grooves, which were made in the pillars after the mortar had set. The main failure mechanisms, ultimate load-bearing capacity and longitudinal and transverse deformations were determined through the experimental testing. In addition, the longitudinal stiffness and the stresses at which cracking appears were determined on the basis of observations and analysis of experimental results. The strengthening effectiveness was also determined in relation to the increase in load-bearing capacity, stiffness and cracking stresses. The methods used for strengthening stocky pillars in bed joints increase their load-bearing capacity, stiffness and counteract cracking without any significant impact on the visual appearance of the pil-lars, which is especially important in the strengthening of historic structures.