Quasi-static cyclic tests of two prefabricated, reinforced masonry walls

In the second half of the 20th century, the majority of residential buildings in Switzerland have been built with unreinforced brick masonry walls and reinforced concrete floors. Following a re-evaluation of the seismic hazard in Switzerland, a country of moderate seismicity, the seismic design spectra have increased in the last revision (2003) of the Swiss building code. As a consequence, it has become very difficult to justify the use of unreinforced masonry walls as sufficient seismic resistance elements. In many new residential buildings, structural walls are constructed as reinforced concrete walls instead of unreinforced masonry walls although the latter provide better thermal and insulation properties at a lower cost. Reinforced masonry systems, which could constitute a viable alternative to reinforced concrete walls, are rarely used within Switzerland. The objective of this research project was therefore to develop a reinforced masonry system unlike most reinforced masonry systems that are available on the international market today. It was decided to develop a prefabricated wall system that would require less construction time and allow an easier introduction to the Swiss market. The most critical construction detail is the connection between the prefabricated wall and the foundation. In a preliminary study two different connection details were developed and their functionality tested by means of quasi-static cyclic tests of full-scale wall elements. This paper summarises the details of the system, the test setup, the instrumentation and the test results. The tests were able to show that the proposed systems achieve similar displacement ductilities as ductile reinforced concrete walls. Finally, recommendations for further improvement of the suggested prefabricated reinforced masonry wall system are made.