Structural connections

Structural connections include nails, screws, bolts, coachscrews, rivets, pins, dowels, epoxied rods, glues and other structural connectors including ply gussets, metal plate fixings, and nail-on plates.

A key part of the design of a timber structure is the connections. A large portion of the design effort goes into designing and detailing the connections throughout a structure.

One of the reasons for the complexity in designing the connections is the anisotropic nature of timber, ie the structural properties are different along different axes.

Another reason is the variable nature of timber with variations in species, grade and individual sticks within a grade resulting in a large variation in the structural properties.

Timber fixing technology has developed over thousands of years, resulting in a wide range of fixings available to the designer. Selection of appropriate fixings depends on factors such as the environment, use, loading and aesthetic requirements.

Key points

Timber connections are a large and complex part of designing in timber.

A wide range of fixings are available.

Selection of the fixing depends on factors such as the environment it will be used in, loading, aesthetic requirements and constructability.

Structural connections

Case study

Weald and Downland Gridshell

Edward Cullinan Architects

Key Features

This museum building provides space for timber restoration and conservation.
The building consists of a timber gridshell covering a flexible space used as both a workshop and function venue.
The undulating structure is made from a weave of curving oak laths that reach up to 50 m in length.
This slim and flexible construction technique projects a feeling of lightness and transparency while the resulting organic form allows the building to sit naturally in the rural landscape.

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Case study

Salvation Army Citadel

Warren and Mahoney Architects

Key Features

A major architectural feature of the building is the exposed wood roof trusses.
They spring from reinforced concrete columns located in a semi-circular pattern near the perimeter of the auditorium.
The trusses span the auditorium, resting on a semi-circular ring beam in the centre, which allows natural light into the space.
This type of construction means the trusses are cantilevered from the columns and restrained to the perimeter wall using steel tension rods.
The trusses are constructed from Douglas fir.

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Case study

Grandstand Roof - Nanterre, France

Barthélémy-Griño Architectes

Key Features

The structurally complex grandstand roof consists of a string of cantilevered space frames, hung on wooden masts tied back with a succession of galvanised steel columns.
The frames were prefabricated in a factory before being transported to the site.
Small diameter galvanised steel cross-bracing members resist wind loads.
The roof is clad with clear corrugated polycarbonate, giving weather protection while allowing natural light to illuminate the structure and seating below.

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