Compressive behavior of brick masonry columns confined with steel composites embedded in the mortar joint: experimental analysis and comparison with FRCM technique

Masonry columns in historic structures often exhibit reduced load-bearing capacity and vulnerability to seismic actions due to their brittle behaviour and limited tensile strength. Enhancing their structural performance while preserving architectural authenticity is a pressing challenge in the field of structural engineering and conservation. This study presents an experimental investigation into a novel strengthening approach involving the integration of pre-tensioned steel micro-cords within the horizontal mortar joints of brick masonry columns. The mechanical response under compressive loading is analysed for both circular and rectangular column cross-sections. The effectiveness of this technique is evaluated in comparison with Fiber Reinforced Cementitious Matrix (FRCM) jacketing, a more widely adopted confinement system. The experimental findings reveal that the embedded micro-cord system significantly enhances compressive strength, yielding an average increase of approximately 87%, outperforming the FRCM solution, which achieved a strength gain of around 45%. Additionally, the proposed method offers the advantage of being minimally invasive and visually unobtrusive, making it particularly suitable for heritage buildings where preserving original aesthetics is crucial. This research highlights the potential of mortar joint-based reinforcement as an efficient alternative to traditional jacketing systems, paving the way for further development of non-invasive strengthening methods for masonry structures