Underpinning method is applied to repair and strengthen building foundations. Foundations fail suddenly and underpinning method helps to regain structural stability. The underpinning process involves installing temporary or permanent support to a weakened foundation for achieving extra depth and burden bearing capacity.
Underpinning Melbourne experts select methods on the basis of structures age and kind of work involved.
- Ancient – < 150 years
- Recent – 50 – 150 years
- Modern – > 50 years
Kind of works
Conversion works –
It means existing foundation needs to be converted for stronger functions.
Protection works –
Existing foundation is unstable and needs basement beneath an existing structure to resist natural calamities.
Remedial works –
Subsidence in existing structure is due to errors in initial foundation design. So, improve the existing structure rather than creating a new one.
Engineers from Urathane Solutions suggest underpinning for structure stabilization. Conditions that cause subsidence in building structures are poor soil stability. This can be due to water table fluctuation. Low and rise of water table cause the soils bearing capacity to decrease making structures settle.
How underpinning gets determined for a new project?
Settlement of existing structure can be established through occasional vertical and offset level readings. Time duration will depend on settlement severity. Before excavation for a new project, soil capability needs to be professionally determined. It is then decided, whether there is a need for underpinning or not.
This test prior start of construction enables to eliminate underpinning application or else it can happen suddenly after the whole structure gets completed. This is an emergency situation for applying underpinning method.
Different underpinning methods
- Mass concrete or pit method
- Needle beam method
- Pier & beam method
- Pile method
- Mini-pile method
- Pre-test method
Each kind of method follows the same concept of expanding the current foundation lengthwise or breadth-wise. It is to be placed over strong soil stratum. Thus the load gets distributed across a vast area. Methods will be determined on the soil conditions and needed foundation depth.
Helpful tips for underpinning
- Start from corners and continue inwards
- Perform underpinning under load bearing walls
Take professional help for successful underpinning results.