Masonry Magazine February 2003 Page. 32
Retaining Wall
SYSTEM
FIG. 1
Original drawings submitted for patent, describing the off-set (single or multiple) tongue-and-groove principle.
The original Pisa Stone idea was for a simple vertical wall. "The original patent did not incorporate setback, it was purely up and down," Risi notes. "In order to incline the wall we actually told the contractor to install the base at an angle. But in 1981 we were issued a patent where each tongue and groove is offset automatically from each other. That meant the wall would gain an automatic setback just by stacking the blocks level on top of each other. We were the first to have the automatic offset if you will."
As retaining wall systems became more common, other companies modified the techniques used in building the walls. The development of geogrid reinforcement mats in the mid-1980s was another changed approach. "Due to their high weight and geometric configuration, our products integrated well with a number of different soil reinforcements," claims Risi. "The composite mass created by the geogrid, engineered fill material, and our strong facing units resulted in a high-performance structure that was a good retaining wall with almost unlimited height potential."
Walls became higher, and with the added height came higher complexity in the engineering. Risi worked with Dr. Richard Bathurst, a renowned researcher in segmental retaining wall technology to continuously test materials and designs. One result of this was the development of RisiWall, a software program for SRW design. The program allows designers to design and produce elevations and cross-section views in CAD drawings for a project. "Much of our current effort has been to make RisiWall 5.0 the most comprehensive design software on the market," explains Risi. "Our licensees use it to stay one step ahead of their competition."
The Risi brothers are devoting their time to ideas, not manufacturing, these days. "We sold Risi Stone Manufacturing but we maintained the licensing of our patented products," Risi says. "Risi Stone Systems is the collection of systems that we have and license under our licensing company."
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FIG 30
FIG.2
30 Masonry
February 2003
FIG. 3
One of the monumental reminders of man building by placing stone on top of stone is the Great Wall of China, the only man-made structure visible by the naked eye from the Space Station.
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