Recognizing Foundations as Sub Building Structure

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Recognizing Foundations as Sub Building Structure

All building construction is designed to be built on the ground and must be supported by a foundation. the foundation is part of an engineering system that continues the load supported by the foundation and its own weight to and into the soil with rocks located below it. The resulting ground voltages except on the ground surface, are in addition to the burdens that already exist in the soil mass from the weight of the material itself and its geological history. The cumulative expenses of the floor and buildings above it (super structure) are received by the foundation (substructure) which deals directly with the land.

The function of the foundation is to safely forward a centralized reaction from the column and / or wall or lateral loads from the retaining wall, to the ground, without the occurrence of differential settlements in the structural system without the collapse of the soil. Conditioning structure buildings depends entirely on the local soil structure.

Land must be able to support and sustain the burden of any construction planned on the land without the occurrence of shear failure and the resulting deflection deflection can be surveyed for the construction. A foundation for building a structure must be sufficient so that the construction has satisfactory use and to be safely occupied. A foundation must be able to meet several stability requirements and deformation requirements such as:

1. The depth must be able to anticipate the expenditure or shift of material / soil in the lateral direction from the bottom of the foundation, especially for the palm and raft foundations.
2. Depth must be below the area of ​​seasonal volume changes caused by freezing, disbursement and project growth.
3. The system must be safe against reversal, rotation. pushing or broken ground (shear strength failure).
4. The system must be safe against corrosion or deterioration caused by hazardous materials found in the soil. This needs special attention when returning to stockpile with good landfill, especially for marine-related foundations.
5. The system must be sufficient to withstand some changes in place or geometric construction.
6. The foundation must be economical in the installation method.
7. The whole movement (generally deflections) and differential movements must be able to be traced to both the foundation elements and the elements of the building above the ground.
8. The foundation and construction must meet the standard requirements for environmental protection.

If the foundation is incorrectly designed, then there will be a part of the structure that has a greater decline than the surrounding area. Various structural elements that meet at the convergence point of the columns will experience more stress due to the unequal decline, which in the end will result in excessive deformation.

Additional bending and torsional moments that exceed the resistive capacity of structural elements can result in excessive cracking due to the melting of the reinforcement, and eventually lead to collapse.

If the entire structure experiences a uniform decrease, only a small or no excess voltage will occur. Such behavior can be studied on very rigid foundations and the soil is so soft that the above structure behaves like a floating object, which can change position without damage.

Examples of such structures can be seen, such as in Mexico City, whose buildings have shallow foundations and have experienced a few feet of decline over the years as a result of the land consolidation process.

Other examples of very slow declines, or also the consolidation process is not uniform, also the gradual loss of structural stability, as happened in the Pisa italy skewed tower, is an example of a non-uniform foundation reduction problem.

The layout plan of a structure is very diverse, as well as the soil conditions can differ in an area and in other areas far apart and nearby. As a result, the type of foundation chosen must be based on these factors, plus other factors, such as economic factors.

In summary, the structural planner must obtain complete land data as needed before determining the type and layout of the foundation of a planned structure. Therefore, it is highly recommended and recommended to have basic knowledge about soil mechanics and foundation techniques before planning a foundation.

To be able to determine the amount of bearing capacity for a particular area and determine the foundation system to be used, basic knowledge is needed regarding the determination of cohesive and non-cohesive soil resistance. Data needed to find out The carrying capacity of the soil is usually determined by drilling the soil or by investigating other land.