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Foundation Reinforcement for Safer Buildings

Discover foundation reinforcement techniques, their advantages and disadvantages, and how to manage everything with the right tools

Foundations play a fundamental role in providing structural support and stability to the entire building. They are literally the foundation on which every structure rests, whether it is a house, a commercial building, or a public work.

Imagine foundations as the roots of a tree: if they are weak or compromised, the entire structure is at risk of collapsing. So, if they are not solid and stable, serious structural problems can occur, jeopardizing the safety of occupants and the lifespan of the building itself.

Therefore, ensuring the stability and integrity of foundations over time is vital for the safety and durability of buildings. Foundation reinforcement aims to strengthen and stabilize existing foundations, preventing structural failure and protecting the building from future damage.

Find out in this blog post how to reinforce foundations, also with the help of a structural calculation software.

Structural failure of a stone masonry

Structural failure of a stone masonry wall

Causes of Foundation Settlement

Foundation settlement is a complex phenomenon that can be triggered by a variety of factors. Below, we analyze in more detail the main causes of this displacement:

Soil Moisture Variations

Soil moisture variations are one of the main causes of foundation settlement. These variations can be caused by various factors, including seasonal changes in precipitation, water losses from water networks, or rainwater losses near foundations. Excessive moisture or its absence can affect the soil bearing capacity, leading to foundation settlement.

Soil Movements

Soil movements, such as subsidence, soil expansion, or contraction, can cause foundation settlement. These movements can be caused by various factors, such as natural geological processes, human activities like natural resource exploitation or soil excavation, or natural events like earthquakes or landslides.

Presence of Tree Roots

Tree roots can pose a threat to building foundations, especially if the trees are located near the foundations themselves. Roots can penetrate the surrounding soil and exert pressure on the foundations, compromising their stability and causing settlement.

Foundation Reinforcement Methods

There are several methods and techniques used to reinforce foundations, each designed to address specific issues and soil conditions. Let’s take a closer look at some of the main foundation reinforcement methods.

Micropiles

Micropiles are one of the most common and effective techniques for foundation reinforcement. This technique involves installing small-diameter piles with greater length than traditional piles. Micropiles are inserted into the soil using hydraulic jacks, reaching more stable soil layers. This method is particularly suitable for foundations in unstable soils or subject to differential settlements.

Resin Injection

Resin injection is another widely used technique for foundation reinforcement. This method involves injecting polyurethane resins or similar materials into the soil surrounding the foundations. The resins fill the voids in the soil, improving cohesion and bearing capacity. This method is particularly effective for foundations located in clayey soils or subject to subsidence phenomena.

Jet Grouting

Jet Grouting is a more invasive technique used for foundation reinforcement in challenging conditions. This method involves using a high-pressure jet of cementitious grout or similar materials to create a new foundation base in the soil. The material is injected into the soil through a perforated tube, fracturing and consolidating the surrounding soil. This technique is particularly suitable for foundations located in poorly consolidated soils or where a new foundation base needs to be created.

Foundation Base Widening

Foundation base widening is a more traditional method used for foundation reinforcement. This method involves excavating the soil around the foundations and applying reinforced concrete beams to support the existing foundation. Subsequently, the soil is filled with gravel to improve load distribution on the soil. This method is suitable for foundations located in poorly consolidated soils or subject to differential settlements.

Structural settlement of brick element

Structural settlement of a brick element

Advantages and disadvantages of consolidation techniques

Compared to the techniques discussed earlier, I would like to focus on the advantages and disadvantages of each method. In fact, each of them presents unique characteristics that must be taken into consideration based on the specific soil conditions and the building’s needs.

Micropiles

Advantages

  • Execution speed – micropiles can be installed relatively quickly, reducing the building’s downtime;
  • Reduced invasiveness – compared to other more invasive methods, the installation of micropiles disturbs the surrounding soil and activities less;
  • Adaptability – micropiles are suitable for a wide range of soils and can be used to address various structural issues.

Disadvantages

  • Cost – the installation of micropiles can be expensive, especially under particularly difficult soil conditions;
  • Limited depth – in some cases, the maximum depth achievable by micropiles may not be sufficient to address deeper soil settlement issues.

Resin Injection

Advantages

  • Adaptability – resin injection can be used to consolidate a wide range of soils and address issues such as subsidence or cavity formation;
  • Cost-effectiveness – in many cases, resin injection can be a financially advantageous solution compared to other more invasive methods;
  • Reduced execution times – this method can be carried out relatively quickly, minimizing the impact on surrounding activities.

Disadvantages

  • Material limitations – the choice of resin type and its characteristics can influence the treatment’s effectiveness, and some situations may require the use of special materials;
  • Risk of leaks – incorrect or poorly positioned injections can cause resin leaks, which could further compromise the soil’s stability.

Jet Grouting

Advantages:

  • Versatility – Jet Grouting can be used in a wide range of soils, including those difficult to treat with other methods;
  • Creation of new foundations – this technique allows for creating a new foundation base in the soil, significantly reinforcing the building’s stability;
  • Reduction of settlements – Jet Grouting is effective in reducing differential soil settlements, maintaining a uniform load distribution on the foundation.

Disadvantages:

  • High cost – Jet Grouting can be costly to execute, especially in very compact or difficult-to-treat soils;
  • Invasiveness – this method is more invasive than others, as it requires the use of heavy machinery and soil drilling.

Base Widening

Advantages:

  • Long-term stability – this method significantly improves the foundation’s bearing capacity, reducing the risk of future settlements;
  • Adaptability – base widening can be used in a variety of soil conditions and tailored to the specific needs of the building.

Disadvantages:

  • Invasiveness – this method requires excavation around the foundations, which can cause disturbance and inconvenience to surrounding activities;
  • Execution times – base widening may take longer than other methods, as it is necessary to wait for the concrete to fully harden before proceeding with construction.

Practical applications of foundation reinforcement techniques

To fully understand the effectiveness of different foundation reinforcement techniques, it is important to examine some concrete examples of practical applications in specific situations. These examples provide an overview of the challenges faced and the implemented solutions, helping guide the choice of the most suitable technique based on the circumstances.

Example 1: Foundations on Clayey Soil

A residential building shows signs of foundation settlement due to the presence of clayey soil subject to significant moisture variations.

Solution – In this case, the use of Jet Grouting could be the best choice. This technique allows for injecting a high-pressure cement mixture into the soil, creating soil-cement columns that improve the bearing capacity and stability of the foundations. Jet Grouting is particularly effective in clayey soils, as it reduces the risk of differential settlements caused by moisture variations.

Example 2: Foundations with Cavity Presence

A historic building shows signs of foundation settlement due to the presence of cavities in the underlying soil, likely caused by erosion or degradation over time.

Solution – in this case, resin injection may be the most suitable technique. Resins are injected into the soil cavities, filling them and consolidating the surrounding soil. This method is particularly effective in restoring the bearing capacity of foundations compromised by the presence of cavities, providing a lasting and relatively non-invasive solution.

Example 3: Foundations with Differential Settlements

A commercial building shows signs of differential settlements of the foundations, with a part of the building leaning due to uneven load distribution on the soil.

Solution – in situations of differential settlements, base widening may be the most suitable technique. This method involves excavating the soil around the existing foundations and widening the base by inserting additional structural elements, such as beams or piles. Base widening redistributes the load evenly on the underlying soil, correcting the effects of differential settlements and restoring the building’s stability.

These examples illustrate how the choice of foundation reinforcement technique should be guided by a careful assessment of the specific site conditions, building needs, and budget constraints. Consulting industry experts and specialized engineers can help make informed decisions and ensure optimal long-term results.

The right tools for structural reinforcement

Let’s now see how to use a structural calculation software optimally for foundation reinforcement. Remember that you can also take advantage of video tutorials that allow you to solve issues in a very easy manner.

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