Back in the spring of 2008, Powell Tolner & Associates were invited to inspect the construction of a basement that appeared to have serious problems. The reinforced concrete box had floated under the pressure of groundwater that had built up underneath the basement slab. Initial levels showed that one corner of this basement had risen as much as 750mm out of the ground! PTA set about establishing the reason for the problem and ultimately a solution.
In May 2008 this video was taken which shows the first core being taken to relieve the pressure of ground water. Following the ingress of water into the basement, the whole structure settled back some 400mm - 500mm in the space of 15 – 20 minutes.
PTA then designed a comprehensive land drainage system developed from carrying out a comprehensive hydrological and geotechnical investigation. PTA also instigated concrete pressure grouting to remove any potential voids and thus stabilised the structure. The resulting development is seen on the final photograph.
