INNOVATIVE SOLUTIONS FOR MASONRY STRUCTURES: CONCEPTION, TESTING AND APPLICATION Paulo B. LOURENÇO Professor ISISE, University of Minho Guimarães, Portugal pbl@civil.uminho.pt Graça VASCONCELOS Assistant Professor ISISE, University of Minho Guimarães, Portugal graca@civil.uminho.pt João P. GOUVEIA PhD student ISISE, University of Minho Guimarães, Portugal jopamago@sapo.pt Abstract The evolution of structural masonry is briefly reviewed, from old thrust line behavior to modern global behavior using shear walls. For modern structural masonry, the use of unreinforced, confined and reinforced masonry is addressed, discussing the influence of seismic hazard and presenting different solutions adopted in developed countries. Finally, two building systems for modern masonry structures recently developed at University of Minho are presented, one based on lightweight concrete blocks and another based on normal concrete blocks. The experimental and numerical work carried out is addressed, together with conclusions on the performance of the system for in-plane lateral loading. Keywords: Building technology, Structural masonry, Testing, Truss reinforcement. 1. Introduction The lack of masonry codes and norms, on top of technological and architectural motivations, has been until recently an important reason for the loss of market in structural masonry. Currently, unified European norms are available and the designers have adequate tools for structural masonry design. The use of masonry in the last 10.000 years occurred with moderate innovation until the 20 th century, based on the principle that masonry possesses a very low tensile strength. The resulting structural form consisted of thick masonry walls with floors made of timber or reinforced concrete (after the middle of the 20 th century). Design based on graphical methods or simple calculations as cantilever walls, without shear walls, lead to increasing thickness from top to bottom. The famous Monadnock building in Chicago, USA, is the exponent of this structural typology with 16 floors and thickness in the base of 1.82m, see Figure 1. Of course, structural masonry design has much evolved and modern design considers the combined behavior of floors and walls. In Portugal, masonry is being mostly used as traditional infill material for reinforced concrete frames. Recently, modern engineered masonry is becoming popular as long horizontally rein-forced non-load bearing walls in non- residential buildings [1]. A major challenge that has to be faced by the brick and block producers is the finding of an effective and attractive load bearing masonry system that is able to convince contractors and designers to use it in low and medium-rise buildings, due to the moderate to high seismicity of the country. 6th International Conference AMCM’2008 Łódź, Poland, 2008