What Are the Types of Underpinning?

Underpinning is the practice of strengthening and stabilizing the foundations of homes or commercial properties to make them suitable for their surroundings. Typically, underpinning is necessary when changes in soil conditions have rendered existing foundations no longer adequate for their intended purposes.

Mini-Piles

Mini piles are ideal for applications where there is limited access, changing ground conditions or underpinning must take place without disrupting day-to-day building activities. Furthermore, mini piles are ideal if environmental pollution or working near existing buildings presents problems – and can be constructed using various systems like pile and beam systems, cantilever pile-caps or even piled raft systems.

Underpinning Melbourne is a permanent solution to an unstable foundation that sinks or settles over time, offering more lasting solutions than methods such as mudjacking or using polyurethane material. So what types of underpinning exist today?

This method of piling involves driving steel casing filled with concrete into the ground, providing greater load capacity and overcoming challenging driving conditions such as heave and squeezing. Commonly referred to by various names depending on industry – pin piles, needle piles and steel driven tubes among them – this form of foundation can be particularly helpful for domestic builds such as extensions and situations with limited access; tests for compressive loads, uplift tension loads and lateral loads may also be conducted on this form of pile foundation.

Drilled Piers

Drilled piers are constructed by drilling holes, installing steel reinforcement, and pouring concrete into them. While drilled piers may reach bedrock, their weight is typically determined through soil evaluation to be at an appropriate limit.

Long reinforcement cages encased in concrete can become compromised from corrosion due to chlorides leaking out, including water and oxygen. As this happens, bars bend/buckle due to Euler buckling which in turn decreases their capacity and could result in damage or failure of drilled piers.

In order to combat this problem, drilled piers can be covered with bell-shaped bottoms or underreams to increase bearing surface area and decrease resistance to bending. However, this method requires careful construction and supervision so as to ensure the piers are installed in their proper locations; typically this technique is combined with other underpinning options to maximize effectiveness at minimal expense.

Driven Piers

Underpinning is a more permanent solution than other temporary repair methods, like mudjacking or polyurethane materials, using steel piers to support and lift back your home to its original position. It offers long term solutions.

Utilizing this approach, foundation experts install hydraulically pushed steel pipe pier segments beneath a sinking structure needing support and drive them down into load bearing strata before lifting them with hydraulic lifting cylinders to the required elevations.

Hand-dug piers may not always be the most efficient or safe solution; this system utilizes helical plates that screw into soil much like wood screws for greater efficiency and safety. They’ve also been field load tested for extra peace of mind. Designed specifically to facilitate access in difficult locations where digging may not be an option, and for use on clay soils.

Needle Piers

Needle piers offer an alternate approach to underpinning, by pushing in at right angles to existing foundation walls – providing more contact and load transfer to new structures.

This method can be utilized when deep excavations are not practical and access is restricted on either side of the wall for digging. Furthermore, this approach serves as a good alternative to pit technique when raking shorelines is required.

Underpinning using structural resins and hardeners involves injecting a mix of structural resins and hardeners directly into the foundation ground beneath footings, where it expands to fill any voids and compact the soil. This method has long been utilized as an efficient way of increasing load-bearing capacity of foundations without needing extensive excavation or disruption to surrounding buildings; additionally it’s ideal for stabilizing unstable columns due to settlement or damage – 30 years later the method remains as a clean, non-disruptive solution!