IN-PLANE RESPONSE OF AN ALTERNATIVE URM INFILL WALL SYSTEM WITH AND WITHOUT A POLYUREA RETROFIT

Masonry units are common building materials in the United States. Clay and concrete are widely used in masonry production, and some other materials such as natural stone are also used as alternatives. An alternative material for infill wall systems was developed by Joshi and Myers [1]. Class-C fly ash obtained from a local coal-fired power plant and wood fibers of white oak obtained from a local tree farm have been utilized as the raw materials for the alternative material. Based on this material development research Hrynyk and Myers [2] studied the out-of plane behavior of the unreinforced masonry (URM) infill walls which utilize the alternative base masonry material. Concurrently with this study, Tinsley and Myers [3] investigated the low velocity impact resistance and near field blast resistance of the material while Carey and Myers [4] investigated the wind borne impact resistance of the material and application in barrier systems. The alternative URM infill wall system is intended to reduce the material cost and to recycle Class-C fly ash and waste wood. In conjunction with an external fiber reinforced polymer (FRP) retrofit, the wall system is intended to provide improved ductility and reduced scatter of debris at the wall failure. The main objectives of the following research study were to investigate the feasibility of applying the alternative masonry unit to infill wall construction and to investigate the effects of an external FRP strengthening system on the in-plane response of the alternative URM walls. The external strengthening system consists of an elastomeric polyurea surface coating and chopped E-glass fibers. The strengthening system has a rapid cure characteristic and is directly sprayed on the wall surfaces. The experimental program of this research study includes manufacture of the alternative masonry units, alternative URM wall construction, wall surface strengthening, and in-plane load tests of the walls.