Effect of footing size on stress zone, Civil Engineering

Assignment Help:

Q. Effect of Footing Size on Stress Zone?

The modulus of elasticity of the soil may be determined by plotting stress-strain diagram based on triaxial test or plate load test. In granular soils it is found that E, increases with depth (i.e. sensitive to lateral pressure). The test sample should be taken at a depth B/2 or B beneath the proposed footing to get an average value of E,. The modulus of elasticity of cohesionless (pure sand) material. will not be influenced by moisture content and particle size. However void ratio affects to a considerable extent. E, is a function of depth in granular soil.

92_Effect of Footing Size on Stress Zone.png

The modulus of elasticity determined from plate load test is to be correspondingly modified as

Let A,, = settlement of plate of width B,,

A = settlement of a footing of width B , = nB,,

q = intensity of stress (constant),

D, = depth of influence for plate Be,

nD= depth of influence for footing tlD1 = Bf,

Ep = modulus of elasticity from B,, and

Ef = modulus of elasticity to use for footing B,.

From Figure the settlement of a plate would be proportional to the depth of stress influence B,. Hence by proportioning

1101_Effect of Footing Size on Stress Zone1.png

But from Mechanics of materials

288_Effect of Footing Size on Stress Zone2.png

Terzaghi indicates that for granular soils the following relationship to be true:

908_Effect of Footing Size on Stress Zone3.png

or solving for E, by appropriate sub situation

233_Effect of Footing Size on Stress Zone4.png

Hence modulus of elasticity of the granular soil can be extrapolated from plate load test. Modulus of elasticity of cohesive soils has been found to be relatively constant with depth. Hence depth correction is not necessary.


Related Discussions:- Effect of footing size on stress zone

Grades of concrete, mixing ratio of different type of ready mix concrete.(R...

mixing ratio of different type of ready mix concrete.(RMC)

Survey, explain ranging and reciprocal ranging

explain ranging and reciprocal ranging

Water-bound macadam road construction for unpaved roads, how can I come up ...

how can I come up with the research on the water bound macadam road construction

Velocity distribution and flow formulae, Q. Velocity distribution and flow ...

Q. Velocity distribution and flow formulae? Variation in velocity along a vertical in channel cross section is known to follow logarithmic distribution, maximum velocity being

major importance of air void content, Question What is major importanc...

Question What is major importance of air void content in bituminous pavements? Answer Air void content of bituminous materials is important control parameter for quali

Expansion jiont, some expansion joint(10 mm- 20 mm) on my basement roof.rai...

some expansion joint(10 mm- 20 mm) on my basement roof.rain water leakage in basement i want the solution of expiation joint and water leakes.

Explain the angle of wall friction, A retaining wall 4.5 m high with vertic...

A retaining wall 4.5 m high with vertical back supports a backfill with horizontal surface. The unit weight of the fill is 18 kN/m 3 and the angle of internal friction is 36°. The

Project costing for Engineering success, Hi I am looking for someone who ca...

Hi I am looking for someone who can help to solve my assignment questions in a subject called project costing and I need him to continue with me until I complete this subject. I a

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd