Post-tensioning Creates New Options for Contractors and Builders
The idea of using post-tensioning to structurally support masonry fencing in lieu of rebar and grout was unheard of in the mid 1980s. At that time, Proto-IITM Wall Systems had developed and patented a post-tensioned masonry fence system called The Proto-II Wall. This system provided an engineered, stronger and less expensive alternative to conventional masonry fencing. Royce Walls of Phoenix, a masonry fence installing company, was one the first Proto-II Wall Systems' licensees and began installing the system for clients in the Phoenix area in 1986.
In the beginning, Royce Walls faced a lot of doubt and resistance about trying a new and unknown product. However, Royce Walls persevered, and through the years Proto-II Walls became more accepted. The builders who used post-tensioned masonry for their fencing projects found them to be an extremely reliable and cost-saving alternative. The system stood the test of time and outperformed conventional masonry fencing, especially in the severe Arizona monsoons. Today, Proto-II Walls are a well-established and highly regarded masonry fencing product among Arizona builders.
While the Proto-II Walls were a superior and cost-saving fencing product for Royce Walls to provide their customers, they did not have a similar alternative to conventional masonry retaining walls. This became an increasing challenge as the market changed. New projects were moving further into the outlying areas of the Phoenix valley where flat parcels of land were scarce. Also, there had been an increase in builders' requirements to provide extensive drainage control, retention basins and between-lot retaining. As a result, retaining walls had become an extensive part of most masonry fencing projects. In addition, retaining walls were expensive and time-consuming due to the increased excavation, bench out, backfill, concrete, steel, grout and labor required to construct them. Because of material shortages and subsequent price increases, retaining walls became more expensive than ever. As retaining walls became a more common and more costly item on job sites, staying within budget became a bigger concern for builders. Proto-II Wall Systems responded to the market needs. Through research, development and testing, they expanded from masonry fencing and introduced the Proto-II Retaining Walls. The retaining walls system uses the same post-tension technology and design as the original Proto-II Walls and yields the same post-tension advantages of increased strength and load capacities. While conventional retaining walls require solid grouting, post-tensioning doesn't, creating significant savings in both materials and labor. In addition, the bench out, excavation, footing size and steel are all reduced due to the unique engineering used in the post-tension design. Another advantage is that Proto-II Retaining Walls can be backfilled much sooner than conventional retaining walls, as no cure time is required for the grout. This results in an additional time savings for the customer.
Immediately, Royce Walls began marketing the Proto-II Retaining Walls to their customers. With increased strengths, reduced installation time and up to 40% savings, Proto-II Retaining Walls became an excellent alternative to the conventional retaining walls. As before, Royce Walls experienced some initial resistance from clients in trying a new and unknown product. However, with Royce Walls' trusted experience with post-tensioned fencing and the increased savings with the product, clients' skepticism did not last long. As more builders discover the advantages, post-tensioned retaining walls are becoming an established alternative in the Phoenix market.
About the Author
Masonry, the official publication of the Mason Contractors Association of America, covers every aspect of the mason contractor profession - equipment and techniques, building codes and standards, business planning, promoting your business, legal issues and more. Read or subscribe to Masonry magazine at www.masonrymagazine.com.