Knox Grammar School ‘Great Hall Project’, Wahroonga, NSW

Martens were engaged to conduct a detailed geotechnical and hydrogeological investigation for the ‘Great Hall Project’ at Knox Grammar School, Wahroonga, NSW.

Martens were engaged to conduct a detailed geotechnical and hydrogeological investigation for the ‘Great Hall Project’ at Knox Grammar School, Wahroonga, NSW. The investigation was required to support the detailed structural design of the building. Martens provided construction stage advice and certification for excavation works and foundation construction.

The Knox ‘Great Hall Project’ was a $35 million dollar construction project which included a multipurpose hall, gymnasium, basketball courts, Olympic sized swimming pool and ancillary structures. The building required considerable geotechnical investigation and design works as there was negligible settlement tolerance due to the configuration of the proposed pool and span of the hall structure.

Project scope included:

• Walkover inspection of the site to assess topography, geology, hydrology and vegetation
• Excavation of 27 boreholes to characterise underlying soils and geology down to 10m below grade
• Rock coring via NMLC methods
• Construction of 5 monitoring wells and installation of groundwater data loggers to allow continuous monitoring of groundwater levels
• Laboratory testing of rock cores (axial and diametral strengths)
• RQD and RMR assessment of recovered core
• Preparation of geotechnical report documenting geotechnical and hydrogeological conditions; provision of geotechnical parameters for design; recommendations for groundwater management; provision of construction monitoring requirements
• Design of soil nails and temporary shoring support for construction excavation
• Inspections during construction to certify foundation conditions and excavation stability