Humans like fences, and as a matter of fact, there are dozens of reasons for them to exist.
Fences are used to protect our children, animals, and other people from falling; they are raised to achieve a higher level of privacy while keeping outsiders away; occasionally they are built to mitigate disturbing noises; and certainly, fences are constructed for aesthetics and decorative purposes. The right fence can be not only valuable and have positive impact, but they can also be majestic and gorgeous.
Despite their tremendous usefulness, up to the present moment there was not a single integrated approach in the New Zealand market to facilitate the process of designing and building a fence or barrier on top of a Segmental Retaining Wall (SRW), while maximising real estate and avoiding an overturning problem caused by either poor construction or relevant surcharges such as vehicles, pedestrians and wind loads.
When discussing SRWs, the resistance to overturning comes from the retaining wall setback and its self-weight, which many times are not enough to resist the localised overturning moments generated when a load is applied to a fence post. The alternatives available in the marketplace to prevent and avoid this issue were very limited and none of them fully satisfactory, especially for engineers and specifiers. Nevertheless, things changed at the beginning of the year when Cirtex Industries introduced Sleeve-It® from Strata Systems Inc, an absolute game changer.
Sleeve-It SD-1 is a pre-engineered fence post anchoring solution for enhancing below-grade foundational stability in fences placed on top of a segmental retaining wall (SRW).
Sleeve-It is a game changer because it shifts the current way we design and build fences on SRWs. Finally, we have a reliable, proven and tested system, which is uniquely designed for easy installation that uses a traditional cantilever design to engage the overlying soil mass, thereby providing resistance to the fence load.
The New Zealand Building Codes under clause F4 – Safety from falling highlights that if there is a fall of 1 metre or more from the retaining wall, the installation of a safety barrier may be required. Some of the factors the Building Code considers are the use of the retaining wall, how accessible it is to the public, and whether it is frequented by people, especially young children. Sleeve-It also complies with the International Building Code (IBC) and the American Society of Civil Engineers (ASCE).
Traditionally the most appropriate place to install a fence or barrier above a SRW was to have at least a 0.9 metre setback from the back of the wall or even further distance behind. Although it reduced the amount of overturning forces applied to the back of the structure, it caused a significant waste of property space. Sleeve-It solves this problem by allowing the fence to be right against the retaining wall, permitting a more effective and profitable way to maximise land use.
Overturning is the main failure mode on SRWs, especially on unreinforced retaining walls. Sleeve-It is designed to accommodate the most common SRW fence types, comparative testing data demonstrates that Sleeve-It outperforms and it is safer than the commonly used construction tubes.
Fences, railings and barriers should never be installed after the retaining wall is completed, instead it is best to do it during while finishing the top of the wall, avoiding the need for extra excavation and the risk of damaging the geogrid reinforcement during construction.
Sleeve-It makes it easy for you, once the post depth, locations, and spacing are determined, the Sleeve-It units are aligned and placed flush against the SRW units. Later, the geogrid is simply accommodated around the obstruction, saving time, and simplifying construction.
Sleeve-It units are lightweight, and their unitary design makes them easy to stack, store and transport to jobsite; reducing stocking space, shipping costs and labour requirements.
Sleeve-It is made from 95% post-consumer recycled polypropylene, which is the best option available in the market to handle the burning of thermoplastic by reducing the discharge of toxins in an eco-friendly and cost-effective way.
Sleeve-It is the ideal product to avoid headaches when a fence or barrier are needed on your block retaining wall. Sleeve-It perfectly aligns with our commitment with sustainable infrastructure, offering products and solutions that not only mitigate harm, but that offer a better and more responsible outcome.