This Small Business Innovation Research Phase II project is designed to develop a reliable and inexpensive method for obtaining insitu measurements of the state of compressive stresses and deformation properties of masonry buildings. Such measurements are essential elements in the evaluation of the structural integrity of existing masonry buildings. Currently these measurements are made using flatjacks (bladders using thin metal sheets welded together at the edges and with inlet and outlet ports). Present flatjack technology has some serious limitations which reduce the accuracy of measurements, limit the types of masonry that can be evaluated and may result in visual damage to the structure. Phase I research surveyed candidate materials that could be used to fabricate a flexible flatjack, designed and fabricated prototypes of flexible flatjacks, and tested the prototypes for applicability to masonry walls. In Phase II, prototype designs will be further developed to improve performance, increase service life and decrease manufacturing costs. Incorporation of deformation sensors will be accomplished and full scale evaluations will also be conducted. Recommendations for modifying existing testing standards, both domestic and foreign, will also be developed as part of the Phase II effort. The need for a new flatjack technology is driven by requirements to rehabilitate existing masonry structures to meet new, more stringent seismic loadings and for use in renovating such structures for changing uses. The large number of existing masonry buildings in the U. S. and the rest of the world and the demonstrated need for evaluation as a basis for retrofit portend a high level of use for a successful new flatjack technology.
