Pad Foundations

Suitable for most subsoils except loose sands, loose gravels and filled areas. Pad foundations are usually constructed of reinforced concrete and where possible are square in plan.

Typical Pad Foundation Types

Strip Foundations

These are suitable for most subsoils and light structural loadings such as those encountered in low to medium rise domestic dwellings where mass concrete can be used. Reinforced concrete is usually required for all other situations.

Foundation Design Principles and Procedure

Foundation Design Principles.- the main objectives of foundation design are to ensure that the structural loads are transmitted to the subsoil(s) safely, economically and without any unacceptable movement during the construction period and throughout the anticipated life of the building or structure.

Basic Design Procedure.- this can be considered as a series of steps or stages

1. Assessment of site conditions in the context of the site and soil investigation report.

2. Calculation of anticipated structural loading(s).

3. Choosing the foundation type taking into consideration  

a. Soil conditions;
b. Type of structure;
c. Structural loading(s);
d. Economic factors;
e. Time factors relative to the proposed contract period;
f. Construction problems.

4. Sizing the chosen foundation in the context of loading(s), ground bearing capacity and any likely future movements of the building or structure.

Simple RC Raft Foundations

These can be used for lightly loaded buildings on poor soils or where the top 450 to 600 mm of soil is overlaying a poor quality substrata.

Short Bored Pile Foundations

These are a form of foundation which are suitable for domestic loadings and clay subsoils where ground movements can occur below the 1„000 depth associated with traditional strip and trench fill foundations. They can be used where trees are planted close to a new building since the trees may eventually cause damaging ground movements due to extracting water from the subsoil and root growth. Conversely where trees have been removed this may lead to ground swelling.