In the late 1970s, a substantial [20 lots] urban residential subdivision was undertaken on a site on the urban outskirts of Wagga Wagga NSW. Later, in the mid 1990s a number of the houses constructed on the various lots experienced substantial cracking, with some of the houses having substantial damage.
Because of the unusual nature of the observed damage, SCE was engaged to inspect and advise the Local Council as to the probable cause(s) of the damage.
SCE then undertook an extensive historical & geotechnical review of the site conditions and discovered that:
- in the early 1900s part of the land had been used as a sawmill and there were a number of sawdust pits over the site;
- the site substrata was subject to significant shrink / swell movements;
- the site was in close proximity to the levee bank of the Murrumbidgee River.
SCE thus determined that the various types of damage observed over the subdivision could be readily accounted for by:
- Footing systems that were too weak to cope with the large shrink / swell movements of the site substrata.
- Large differential settlements related to the remnant sawdust pits and inadequate site remediation following its use as a sawmill.
Subsequently, and in light of SCE’s findings, the Council was then able to assist the residents and property owners in resolving the damage to their houses.