Boxley Bridge - Timber Bridge Replacement - Geotechnical Analysis

Summary and scope

The Walcha Council is planning on replacing “Boxley Bridge”, a timber bridge over the Pipeclay Gully on Niangala Rd, approx. 18.5km West of Walcha. The current bridge will be demolished prior to its reconstruction at the same location. During the period of the works, a by-pass shall be created parallel to the existing bridge to allow traffic to cross the Pipeclay Gully. To effectively define the bridge’s scope of work, an investigation is required to provide the following: • Subsurface conditions and geology in the area of the proposed bridge; • Groundwater level, if encountered; • Soil and water aggressiveness; and • Shallow and piled footing options and design parameters for bridge footings (allowable bearing pressure and shaft adhesion) and strength reduction factors. The investigation shall include the drilling of boreholes, laboratory testing of selected samples and the preparation of a report. The details of the field work shall be presented in a report, together with comments and recommendations on the items listed above.