Working with our structural engineer and our metal fabricator, we came up with our unique hub design.
The entire hub is a one piece, very high strength, aluminum extrusion.
The tongue from the sleeve fits onto the slot around the perimeter of the hub. Having squashed various pipe hubs during testing, we came up with integral reinforcing spokes to strengthen the hub. It now could take extreme pressure from the struts-both pulling and pushing.
So sure were we that we had a fantastic dome connection system, we obtained a patent, #4,262,461.
The need for a super-strong connection device for domes becomes evident in examining how the dome framework reacts to loads:
The dome framework transfers all of the roof loads directly to the base of the dome. These loads get added to each other on the way down. The lower part of the dome has to be able to take 6,000 - 10,000 pounds of pressure at each lower connection point. This means that the weakest link in the ”chain” has to be able to take this pressure.
Our Super-Lok connector has been tested independently. Tests were run with our sleeve mounted on the #1 grade southern pine strut. This better resembles actual load situations.
The test tried to pull the wood strut (with our Super-Lok sleeve) from the hub. The wood split at over 15,000 pounds but did not actually come apart. Our sleeve has four 1/2" bolts connecting it to the strut. One of our competitors uses 2 bolts in attaching a bracket to their strut. They use fir lumber which is not as strong as southern pine. Even though they use 5/8” bolts, our connection system would still hold at least 40% more stress.
For areas of the World with increased snow and wind loads along with earthquake areas, we have created our Ultra-Lok connector. This steel sleeve is larger, allowing the bolts to be spaced further apart and asymmetrically. The independent tests show the connector capacity increased 33% to over 20,000 pounds of stress.
Over the past 40+ years, we have done extensive computer engineering analysis on our dome with our structural engineers. Our system has always surpassed the structural needs of the building codes, even as they have become more stringent. Engineering done in 2014 showed that our domes will take at least 100 pounds per square foot ground snow load, along with a wind load of at least 150 mph (defined as a 3 second gust).
Earthquake loads, along with heavier snow and wind loads, can be handled using our Ultra-Lok connector.
Our engineering also combines these loads, adding the snow, wind and earthquake loads to the dead load of our dome structure. This combination loading creates what is called ”eccentric” loading where all of the normal roof snow and wind load is put on only 1/2 of the dome. Again we surpassed the structural needs.
We think our Natural Spaces connector is the strongest dome connector on the market. Our competitors have been heard to say our system is over engineered - we think you deserve nothing less.
Super-Lok™ Dome Connector Prices:
Prices shown below are for our patented Super-Lok Dome connection system only. This allows you to cut and fabricate all your own dome components.
Attic (View) Cupola Roof Package (Upper portion only) Add $93 for necessary additional hardware. (Templates, Ultra-Lok Sleeves, Bolts, Nuts, Washers)
Attic Cupola Floor Package (Skyloft-Lower portion only) Add $178 for necessary additional hardware. (this floor package is not available for the 16’ - 29’ diameter domes) (Template, Ultra-Lok Sleeves, Hub, Bolts, Nut, Washers, Pins)
Ultra-Lok™ Dome Connectors
Introduced in 2006 for our biggest domes, we are also able to increase the structural strength of our domes in areas with earthquakes, hurricanes, tornados and extremely heavy snow loads. Check with us for prices of smaller domes using the Ultra-Lok™ connector.
Paul Durand, Professional Engineer (P.E.) and Structural Engineer (S.E.), has been our consulting engineer since 1987. With his direction, we created our Ultra-Lok™ dome connection system. Our Ultra-Lok™sleeve mounted on extremely high grade 2 x 8 Southern Yellow Pine wood struts was brought to an independent testing lab, Twin City Testing. Through sophisticated machine testing, they showed that our Ultra-Lok™ connector increased the load capacity of our already strong dome system by more than 33%.
The Ultra-Lok™ system is available in all of our dome sizes for an increase in cost. If you are in an extreme wind area (straight line winds, tornados, hurricanes), this system can be engineer certified to meet your local codes.
All riser wall corners in all sizes of our domes use our Ultra-Lok™ sleeve. They are included in prices shown above and below.
To order any of the above components, Call or Email us.