n’H International AG
Obseestrasse 11
6078 Lungern
Switzerland
+41 41 679 70 80
office@neueholzbau.ch
GSA TECHNOLOGY,
GSA BASICS.
Glued threaded rods are among the most powerful connectors in modern timber construction engineering. Whether they are glued in parallel or perpendicular to the grain direction, powerful forces can be applied in small areas of wooden components. In conjunction with Professor Ernst Gehri, neue Holzbau AG (n’H) has been conducting research in this area since the late 1990s. Under the brand name ‘GSA technology’, a range of solutions has since been developed that are being successfully applied in various timber frameworks all over the world.
Wood, resin and steel form an interlocking system, requiring the harmonisation of all three components’ properties. Certain rules and conditions must be complied with if optimum connections are to be created. To avoid any brittle fracture modes of either the wood or the adhesive, connections must be designed so that it is the steel rods (ductile) that fracture in a state of failure.
TESTIMONIAL BY:
Roberto Crocetti
Adjunct Professor at KTH | Kungliga Tekniska högskolan
Connections are often the Achille’s heel of timber construction. Traditional connections for heavy timber structures, such as the one with slotted-in plates and dowels, cause a severe reduction of the cross section in order to be able to allocate the necessary number of fastener and other steel devises. This result in a significant reduction of both the load bearing capacity of the joined timber parts and of the structure’s stiffness. The GSA technique is an excellent way of joining timber members by means of bonded-in rods and special steel devices attached at the one end of bar. The design of the connection is such that ductile modes of failure, rather than brittle, are promoted. Since the timber cross sectional reduction when using the GSA technique is small, the load carrying capacity of the joined loading bearing members is not severely reduced due to the presence of the connection. If needed, the capacity GSA technique can further be improved by locally strengthening the timber members to be connected by means of stronger wood materials, such as beech or ash. The GSA technique allows for the creation of both hinges as well as moment resistant connections. Finally, from the aesthetic point of view, GSA technique allows for very appealing structures.
GSA LMV
Frame corner connectors at maximum load level. It is easy to design frame structures with various shapes and angles using this GSA LMV connection. This plug-in solution is excellent from design to installation.
GSA FW
Breaking a profile down into a framework instead of solid beams means that building materials can be used more efficiently. The timber is mainly subjected to tensile and compressive forces parallel to the grain, so that the advantages in terms of both strength and rigidity can be fully achieved. The capacity of the connections at the joints is crucial for cost-effectiveness. The supporting structure can be optimised to the highest load level by the targeted use of hardwood.
GSA G
Targeted transmission of force at supports, at the ridge or frame corners can be resolved using the GSA-G connection.
GSA R
The GSA-R connection was designed for all types of articulated joints:
- Beams to columns
- Secondary beams to primary beams
- Ridge connections
- Gerber joints
This also allows a rigid connection between beams and columns if they are designed to traverse (e.g. for large canopies).
GSA T
The GSA-T makes it possible to transfer girder loads to the columns without lateral pressure issues. The short support length restricts the torsion of the beam only minimally. In addition, the GS anchors improve dimensional accuracy in case of humidity fluctuations.
GSA AL
GSA technology is ideal to transfer high loads. We have a wide repertoire of tried and tested solutions for articulated connections and fixed supports. Our engineers will be happy to assist you in detailing your connections.
GSA ALP
The GSA ALP procedure (alternative load path) is generally applicable for openings and shear reinforcements in beams. Openings of up to 50% of the beam height can be made without weakening the shear resistance.
GSA R&D
GSA technology is being continuously developed in our own test laboratory, which makes it possible to verify dimensioning models. Applications in various materials are constantly being expanded.
GSA H
A skeleton construction promises maximum flexibility in the room layout. Ductile areas can also be formed in the frame construction, which neutralise the force of an earthquake. This requires rigid and resistant column beam connections. At the same time, weakening of the columns should be kept to a minimum. The GSA-H knot meets these requirements. In combination with hardwood, it has considerable advantages with minimum space requirements, high rigidity and an attractive appearance.
GSA HBV
Wood-concrete composite
These composite panels have several advantages:
- High load-bearing capacity with a low intrinsic weight (ideal for large spans)
- Space for installations between the beams (system separation)
- High slab rigidity for horizontal load transfer (in case of an earthquake)
- Good performance in terms of soundproofing and fire protection, heat storage function possible
- Advantages of the GSA-HBV shear connectors, specifically:
- High rigidity ensures great efficiency of the composite section.
- Due to the ductile behaviour, the shear flow is distributed reliably among all connectors in use.
GSA L
Limited transport dimensions require assembly joints for large structures. Column loads should be transferred through beams without deformations, or beams should have a rigid connection to columns. The GSA-L pin and socket system makes it easy to assemble high-strength connections.
GSA SAN
Static renovation of existing timber structures to restore the required safety levels. First, the affected (damaged) areas must be removed. With the GSA-Technology, new parts can then be attached to the existing structure friction-locked.
GSA VGS
This GSA cast joint is used for assembly joints with high forces and to realise special geometries. It is also often the best solution even for normal construction tolerances. This connection is cast on the construction site by the n’H team using a mortar. Simply tell us the normal forces, shear forces and torques and our engineers will calculate the connection.
GSA VS
The principle of pre-tensioning can be found in many areas of structural engineering. Steel strands are guided through tensile stressed parts of the supporting structure and tensioned. The resulting compressive stresses increase the tensile strength of the component. This technology can also be useful in timber constructions. Large load-bearing structures, which often include assembly joints, can thus become more delicate and at the same time more economical.
GSA WV
Bracings in walls and roof surfaces serve to spatially stabilise the load-bearing components. In most cases, the columns and beams achieve their maximum load-bearing capacity only thanks to these constructions. Our bracings provide the necessary rigidity and load-bearing capacity and are easy to install. With the ‘plug-in brace’, only two bolts are required for assembly, and the WV rod assumes its stabilising function.
Contact.
Aino Werp
Architectural services and distribution in Norway
Phone: +4790550077
Email: aw@control.no
GSA technology connects. Perhaps it’ll even connect you to nH International AG. Are you planning a project? We are pleased to offer you an informal consultation free of charge.