The considerable variability and complexity of masonry heritage buildings means that choosing the most appropriate structural strengthening techniques is difficult.

Modern techniques and innovative materials are often quite rapidly proposed and allowed in current practice, since they must be based on suitable knowledge of both existing and new materials. Numerous innovative products have been developed (FRPs, bars, strips, laminates, sheets, grids) and various materials have been proposed such as high tensile steel wires,etc. 

I have attached a few relevant articles.

http://www.sciencedirect.com/science/article/pii/S0950061805000218

http://www.archquake.com/pdf-pubblicazioni/Assisi2001.Cultural%20Heritage.pap.pdf

http://link.springer.com/article/10.1617/s11527-006-9188-7#page-1

http://link.springer.com/article/10.1617/s11527-014-0359-7#page-1

Conference Paper Criteria and technologies for the structural repair and stre...