Mat Footing Rcc Example

Example 3 design a strap footing to support two columns that spaced 4 0 m center to center exterior column is 80cm x 80cm carrying 1500 kn and interior column is 80cm x 80cm carrying 2500 kn 18 19.

Mat footing rcc example.

Numerical problems example 1 design an isolated footing for an r c. Use m20 concrete and fe 415 steel. 375 mm on center for the main reinforcement in each direction for both top and bottom reinforcement any additional bars required in any area can be provided at a spacing of 5 7 5 15 or 30 in. However under certain circumstances it may be desirable to construct a footing that supports a line of two or more columns.

The building has a 10 ft high basement. Column of size 230 mm x 230 mm which carries a vertical load of 500 kn. Raft mat foundation is used in those places where we have less bearing capacity of the soil. The bottom of the footing is 13 ft below finished grade.

At those places we use mat foundations to distributes the whole loads of the structure to the soil when the area of the footing was increase than the soil load bearing capacity will also increase because this foundation reduces the stress on the soil at the same place. Example 3 1 find the resultant force location. 125 190 375 or 750 mm. These footings are referred to as combined footings.

2 assume the length of any foot let we assume l1 2m. For example if the mat foundation is 6 ft 2 m thick and no. Raft foundations sometimes known as matfoundations are a large concrete slab which can support a number of columns and walls the slab is spread out under the entire building or at least a large part of it which lowers the contact pressure compared to the traditionally used strip or trench footings. Mat foundations introduction under normal conditions square and rectangular footings are economical for supporting columns and walls.

Instructional materials complementing fema p 751 design examples counteracting load w largest e again combining loads on footings a 5 and a 6 including the overturning factor and neglecting the weight of the footing and overlying soil p 8 kips m xx 5 712 ft kips m yy 126 ft kips negligible foundation design 19. The safe bearing capacity of soil is 200 kn m2. 29 bars have been provided at 15 in.