Bowstring trusses

The revival of timber construction generated by Australian architects in the early 1960s led to the development of specialist timber fabricators. In Melbourne, H. Beecham and Co. Ltd. developed a specialist timber engineering section and built their complex at Altona North as a showcase of timber construction. The bowstring truss resawing mill was the largest building constructed on the site. Its design seems to be directly inspired by the bowstring truss design presented in the CSIRO's 1958 Timber Engineering Design Handbook.

While specialist engineering practices in the 1950s took advantage of timber's flexibility and economy in industrial buildings, their compatriots in the 1960s appear only to have designed timber industrial buildings for clients with a direct interest in timber and timber products. The Beecham's buildings are an example of this.

Engineer

A. H. Munro

Owner

J. Wright and Sons Pty Ltd

Builder

H. Beecham and Co Ltd

Location

188 Blackshaws Road, North Altona, Victoria

Date Completed

1962

Description

The roof of the mill building is constructed of bowstring trusses on solid timber columns. Each truss has a spaced pair of glue laminated members for the bowstring top chord, built up from 4 scarf jointed laminations, a spaced pair of sawn members for the bottom chord and sawn web members. All the web to chord joints use bolted split ring connectors. Steel connection plates, shear connectors and bolts fix the spaced pair of knee brace members to the truss and supporting columns. The knee braces provide lateral stability to the building while steel tension rods brace five full transverse bays of the building in plane of the wall and roof.

References

Australian Timber Journal 1966, 'Victorian Commission builds Timber Pavilion', July, p. 81-85.

Foundations 1963, 'H. Beecham and Company develop timber engineering section', no. 5, p. 29.

Pearson, R. G. , Kloot, N. H. & Boyd, J. D. 1958, Timber Engineering Design Handbook, CSIRO and Melbourne University Press, Melbourne.

Legend

1. Bowstring truss

2. Steel rod bracing

3. Laminated top chord, 2/200 x 100 mm

4. Bottom chord, 2/125 x 100 mm

5. Column, 340 x 300 mm

6. Web, 150 x 100 mm

7. Web, 100 x 100 mm

8. Knee brace, 2/150 x 100 mm

9. Splice joint

10. Steel connection plate

11. Bottom chord tie

Captions

a. The resawing mill

b. Bowstring trusses