This approach is generally referred to as the compensated foundation design and is extremely useful when structures are to be built on very soft clays.
Mat foundation design example pdf.
Design of raft foundation page 13 3 3 0 why raft should be used.
Load path and transfer of seismic forces.
Foundation foundation design 27 mat.
It is used where the supporting soil has low bearing capacity.
Compensated foundation the net pressure increase in the soil under a mat foundation can be reduced by increasing the depth d f of the mat.
The bearing capacity increased by combining all individual footings in to one mat since bearing capacity is proportional to width and depth of foundations.
Example 8 3 4 see example 8 3 4 in textbook page 363.
The properties used in the analysis and the design of this raft foundation are shown in table 4.
Example 5 1 completes the analysis and design of shallow foundations for two of the alternative framing arrangements considered for the building featured in example 6 2.
Although mat foundations are more difficult and more costly to design than individual spread footings they can be used effectively.
Example 5 2 illustrates the analysis and design of deep foundations for a building similar to the one highlighted in chapter 7 of this volume of design examples.
A mat foundation also may be used to resist hydrostatic pressures or to bridge over small soft spots in the soil provided the mat is adequately reinforced.
This foundation will be used for a loose sand soil.
45 x95 x7 0 with top of mat 3 6 below grade.
Force on a pile eq on unloaded pile.
Instructional materials complementing fema p 751 design examples foundation design 3.