Guia para o planejamento e construção de fundações de edifícios

Guide to planning and constructing building foundations

June 6, 2024 Roberto Magalhães

Building foundations are categorized based on parameters like type of structure, applied loads, soil conditions, environmental conditions, etc.

The most important part of the structure is the foundation. Therefore, special attention should be paid to completing the foundation.

Building foundations are the same as foundations built to build other structures.

There are essentially two types of foundations.

Shallow foundations
Deep foundations

Shallow foundations

The most commonly used type of foundation for low-rise buildings is the shallow foundation. Of the shallow foundations, individual foundations are the most common and economical building foundations.

Individual foundations
Combined foundations
Strip foundations
Mat foundations
Belt foundations

Most of you are familiar with the types of foundations mentioned above. Let's talk a little more about strip foundations.

Belt foundations

Strip foundations are a special type of foundation built due to limited space. Due to limited space, buildings are built right up to the border. In these situations we cannot place the pillar in the center of the foundation. The foundation must be placed on the edge of the foundation.

Due to the eccentric load on the strip foundation, it is necessary to provide a beam as shown in the figure above to balance the pressure under the foundation.

Constructing strip foundations is more challenging compared to other types of building foundations as it requires more digging and skill.

Deep foundations

For low-rise buildings (1-5 stories), deep foundations are not common unless the soil is weak. Some of the deep foundations are as follows.

In situ concrete bored piles
Driven piles – Prefabricated piles
wooden posts

Factors affecting the type of foundation

Let's discuss the main factors that need to be considered when choosing Types of foundations .

Applied loads

When designing building foundations, there are two main types of loads to consider: vertical and horizontal loads.

Article Types of loads on structures and different types of lateral loads For more information, continue reading.

Type of structures

The type of structure greatly influences the selection of the type of foundation. A normal structure has only vertical and horizontal loads. However, irregular structures can create tilting forces necessary to support building foundations.

Soil texture

The most important factor that affects the type of foundation is the type of soil .

The type of construction and design of the foundation depends exclusively on the soil layers existing on site. The parameters determined from the subsoil investigation are used to evaluate the type of foundation.

If the ground is weak, even in a small building, ground improvements may be necessary. If it is not possible to obtain sufficient load-bearing capacity with a shallow foundation, we must construct the building on a deep foundation.

Article Ground Improvement for Low-rise Buildings , Ground Improvement Methods and Ground Stabilization For more information, continue reading.

When foundations are not designed properly and load capacity is not taken into consideration, foundation failure occurs. Foundation Failure AND Shallow Foundation Failure For more information, read on.

Liquidation of building foundations

The biggest challenge in constructing building foundations is laying the foundation. This problem occurs mainly in shallow foundations.

Uniform settlement at each column position is not a problem. Different causes of settlement in columns lead to maintenance problems and can even lead to structural failures.

When building individual foundations, the foundation area must be chosen so that the pressure under the entire foundation is approximately the same. Then the foundation settlement is uniform.

Article Laying Shallow Foundations And Consolidation Processing For more information on this topic you can read.