Reinforced Concrete Mat Foundation Design

Nehrp seismic design technical brief no.

Reinforced concrete mat foundation design.

As analytical capabilities have improved primarily in the form of finite element analysis the mathematical modeling of these continuous structural elements has led to seemingly more precise designs. A mat foundation is a thick reinforced concrete slab supporting arrangements of columns or walls in a row or rows and transmitting the loads to the soil. Where the differential settlement between columns will be small design the mat as reinforced concrete flat slab assuming planar soil pressure distribution. A waterproof membrane sheet is placed over the ground surface and then 4 pcc is poured to create a level base for the mat raft foundation.

A guide for practicing engineers published august 15 2012 author s ron klemencic ian mcfarlane neil hawkins. It can model analyze and design any combination of two way mat raft slabs individual footings pile caps or grade beams. It is used to support storage tanks industrial equipment silos chimneys and various tower structures. The method is generally applicable where columns are more or less equally spaced.

The slab is idealized as a mesh of rectangular plate finite elements with four nodes at the corners and three degrees of freedom dz rx and ry per node. After the pcc reinforcement steel bars are tied cage in place and then the desired thickness of the concrete according to the design is poured. Why mat is used. For analysis the mat is divided into mutually perpendicular strips.

7 seismic design of reinforced concrete mat foundations. Basic design criteria concentrically loaded d 2 all sides c critical section for two way shear b critical section for one way shear a critical section for flexure outside face of concrete column or. A discussion is presented. 4 3 approximate plate analysis.

Spmats program uses the finite element method for the structural modeling and analysis of reinforced concrete slab systems or mat foundations subject to static loading conditions. The difference between strong connection and ductile connection precast design is defined.