Development and Usage of Ductile Composite Materials for Retrofitting and Strengthening of Masonry Structures

Abstract

Brick masonry with concrete elements is extensively used in the construction of multistorey buildings throughout the world. Moreover, most of the heritage structures are also constructed with brick masonry. However, the strength and ductility of these brick masonry structures are limited. Furthermore, strengthening and rehabilitation of deteriorated masonry structures have been a major issue in the last decades. The deterioration of these masonry structures might be due to ageing, corrosion, poor maintenance, poor initial design or construction and accidental situation like earthquakes. Many of the brick masonry structures collapsed during 2001 Bhuj (Gujarat) and 2005 North Kashmir earthquakes. Since the steel as strengthening material is corrodible and conventional strengthening patterns are not highly durable. Usage of non-corrodible, high strength and highly ductile materials for strengthening of brick masonry structures seems to be a potential solution for the above-mentioned problems. Therefore, it is essential to use such high-performance materials for constructing and strengthening of brick masonry structures. Use of Fiber Reinforced Polymer (FRP) bars/ fabrics and Engineered Cementitious Composite (ECC) have shown satisfactory results to give maximum strength along with ductility and durability with little maintenance requirements. ECC is an innovative cement-based composite construction material which uses polymeric fibers with very less fiber volume fraction, i.e., about 2%. This material shows unique strain hardening behavior in tension. ECC is also known as Ductile Fiber Reinforced Cementitious Composite (DFRCC) due to their ultra-high ductile behavior. In this study, an attempt is made to use and demonstrate ECC and FRP as an effective and potential strengthening materials for masonry structures. This thesis presents the results of experimental investigation pertaining to the structural response of masonry elements (beams and walls) strengthened with FRP and ECC.