Six Underpinning Techniques and the Foundation

Rectify Underpinning Melbourne strengthens and repairs building foundations. Underpinning is a method for strengthening and repairing building foundations. In some cases, a failure in the foundation or footing can occur after the entire structure has been built. This includes both the substructure as well as the superstructure.

A remedial solution is needed to restore structural stability in such an emergency situation. This method is used to strengthen the foundations of existing structures or infrastructures. This includes the installation of extremely durable, or even temporary help for a foundation that is generally supported with the aim to increase its depth and carrying capacity.

The selection of underpinning methods

The choice of underpinning techniques is based on the type and age of structures, as well as their inclusion. According to its age, the structure is classified as follows:

Ancient Structures: structures older than 150years.

The age range of recent structures is between 50-150 years.

-Modern structures: under 50 years of age

The Types of Works that Support Methods Selection

Conversion Works

-Protection Works

-Remedial Works

Conversion Works

This structure will require a new foundation that is more stable than the existing one.

Protection Works

It is important to protect the structure and its surrounding issues.

It is not stable.

2.Removal of soil near the footing could affect it.

The soil around the foundation should be stabilized to prevent normal catastrophes.

Storm cellars are required under all existing buildings.

Remedial works

The foundations of the structures have been weakened by errors in their initial design.

It is better to work on your existing structure rather than build a brand new one.

The Underpinning of Structures

The engineer may need to suggest a method of adjustment substructure for a variety of reasons.

The debasement and degradation of wood piles that are used to build typical structures can cause settlement. Degradation of the structures occurs because water tables vary.

Water table fluctuations can reduce the soil’s bearing capacity, causing the building to move.

3. Structures which are placed on soil that is not suitable to support the structure will cause settlement.

Substrate is needed

Note that the decision of whether to use underpinnings is based on observed facts. It is crucial to measure vertically the level of the structure, as well as the offset, when the existing structure starts to exhibit changes. Time-frame depends on how severe the settlement.

Before exhuming soil in preparation for another project, it is important to examine the soil and assess its ability to withstand the new structure. The decision to underpin is made in light of the findings. Often, the test is done only after the structure has been built.

Fundamental Methods

Here are the various underpinning techniques used to reinforce foundations.

-Mass Concrete Underpinning Method (Pit Method)

Cantilever Needle Beam Underpinning

Pier and Beam Method

Mini Pilled Substinning

Pile Method of Underpinning

Pre-Test method of underpinning

The underpinning techniques used to reinforce the foundation all share the idea that the foundation should be extended either in length or width and laid on a firmer soil. It allows for the distribution of weight over a wider area. A variety of underpinnings methods will be discussed in the next few sections. Decisions about underpinning depend on ground conditions as well as the required depth of the foundation.

Mass Concrete Underpinning Method (Pit Method)

Underpinnings using mass concrete or the “pit method” are the most traditional methods. They have been around for hundreds of years. It involves widening the foundation to reach a stable layer. Under the foundation, soil is gradually uncovered by using pins or stages. Once the suitable strata are reached, concrete is poured into the exposed soil and left to dry before removal.

A second pin, set through the dry cement-sand pack, is needed to transfer load. The method is low-cost and suitable for a shallow foundation. There are other methods that can be used to solve more complicated foundation problems.

Cantilever Needle Beam Underpinning

This method is an extension of the pit method. If the foundation is only required to stretch one way and the design has a firmly grounded column, then the cantilever needle beam method may be used.

Cantilever Needle Beam Technique: Its Advantages

The traditional method is slower.

It only has one side entry.

– It is a heavy duty machine.

Cantilever Needle Beam Technique: Its Disadvantages

Digging is uneconomical, but the foundations already in place are profound.

Accessibility restrictions limit the use of needle-beams.

Pier and Beam Supporting Method

After the Second World War, it was called base and beam. It was developed because the mass-concrete method could not be used for foundations of great depth. The majority of ground conditions are suitable. In this case, reinforced concrete beams have been set up to transfer the weight to mass concrete bases. The depth and size of the beams are determined by the soil conditions and loads. For depths below 6.0 m, it is practical.

Mini piled underpinning

It is used when soils are difficult to reach, and the access can cause environmental problems. This method involves driving steel-cased or guided forecasted piles with a diameter of between 150 and 300 mm.

Use of Pile Underpinning

The piles that are used in this method of foundation support are placed on either side of the divider. In this method, a pin or needle is inserted through the divider which supports the foundation. These needles serve as covers for the piles. This can be used to treat settlement in soil due to clogging of the water or clay nature.

The Pre-test method of Underpinning

This product is used for pad or strip basis. The system can handle a range of 5.0-10 stories. In the newly removed level the subsoil has been compacted to give the soil predetermined loads. The underpinning is then performed. It is normal to hear a lesser amount of noise and interruption. This technique cannot be applied for rafts.

This article discusses what underpinning means, the types of work that underpinning method selection can be used for, structural conditions requiring underpinning.

Leave a Reply

Your email address will not be published. Required fields are marked *