Turb-O-Truss™ components comprises:

Turb-O-Web™ curved web components:
These timber web members fit together in the truss configuration similar to a bag full of balls…..all timber members have a tight fit. The main advantage of this method is that the truss joint always has a tight fit, and curved webs allow for varying angles, yet is manufactured in standard stock lengths..

Curved Webs allow for varying angles without any further cutting

Turb-O-Truss™components are therefore immediately available for truss assembly when a specific truss is to be produced, unlike factory made prefabricated roof trusses, where the timber web members cannot be cut to the correct lengths and angles until the time of a specific truss order has been placed for a particular project. Sometines, these factory cut webs are inaccurately shaped as a result of a lack of attention to detail by the saw operator, as can be seen from the examples below. (back)

Poorly fitting webs on trusses can weaken the truss (back)

The patented pre-shaped Top and Bottom Turb-O-Chords

Truss with different roof pitch utilising the patented Turb-O-Chord(back)

Turb-O-Connector The patented Turb-O-Connector comprises a pre-punched galvanised mild steel metal plate, which incorporates strategically positioned “plate positioning” spikes and loose galvanised nails to be inserted over the truss joint on the building site. Both the size of the nail holes, the hole spacing, hole configuration, as well as the length of the galvanised nails to be inserted have all been thoroughly tested by the Department of Civil Engineering of the University of Pretoria. All the test results are on record with the patent holder. The Turb-O-Connector is 20% thicker steel than those used by the factory manufactured prefabricated truss industry (back)

The Turb-O-Truss™ has been tested
Both the Turb-O-Truss™ comprising the Turb-O-Web™ rounded timber webs combined with the Turb-O-Connector has been fully tested by the Department of Civil Engineering of the University of Pretoria, under the leadership of Dr. Wally Burdzik. The confidential test results, which were extremely favourable for the Turb-O-Truss™ system, are well documented. An article with regard to the Turb-O-Web™ has been published by Dr. Burdzik, and is available on request. From the results, which determined the nail values, it has been possible to prepare limiting span tables for the Turb-O-Truss™. Although it is possible to manufacture the trusses up to maximum spans of around 18meters, this would not be required, as the focus of the Turb-O-Truss™ is the low cost mass housing market for gable to gable roof trusses.

Below are some of the photographs taken during the destruction tests of the trusses at the University of Pretoria.

Joint Design
It is a well established fact that truss fabricators generally use much larger connector plates on a truss joint than that which is theoretically required to withstand the forces in such a joint. There are several good and valid reasons for this practice, such as:

• • The connector plates must not only withstand the long-term forces in the joint for which they have been designed, but the plates must be able to withstand handling forces of at least 1500 N (in plane).
• • A 6mm edge distance and 12mm end distance is excluded when calculating the effective joint area as can be seen from the picture below
• • Further more, a 5mm allowable plate positioning tolerance is incorporated in the design criteria.

The SHADED area is the area taken into account in designing the joint

Having defined the above criteria, there is no concern that the Turb-O-Connector joint has a small opening between the two curves of the web-ends in the joint as most of this area is in any case excluded from the effective area in the joint design regardless of the type of connector plate used. This is demonstrated below;

The shaded area is what is called the effective plate area

Each joint is engineer-designed to conform to SABS 0163 so as to transfer axial forces from members as well as bending moments, and is guaranteed for the life span for which the truss has been designed. The rounded Turb-O-Web™ member ensures a tight fit in the joint.

The fact that the rounded Turb-O-Web™ members are being used daily in over 60 truss manufacturing facilities in the USA and Australia is ample proof that the rounded web-end solution has been thoroughly tested internationally. In South Africa, the use of the rounded web in a truss factory is illegal unless a license for such use has been granted by the patent holder, Dr. Ralph Sorensen.

The Turb-O-Truss™ Guarantee
The Turb-O-Truss™ is guaranteed for the life span for which it was designed subject to it having been assembled in accordance with the specification supplied. (back)