Foundation Engineering

CE482

Foundation engineering course aims at providing engineering students in their senior year with the knowledge that enables them to designfoundation for engineering structures. this includes shallow and deep foundations. The design must be safe and economical and can be practically constructed.

Course syllabus

1-subsoil exploration

i-subsoil program

soil sampling,disturbed and undisturbed samples

ii-field tests

standard penetration test.SPT

cone penetration test.CPT

vane shear test

geophysical tests

iii-boring logs

iv-rock coring

v-subsoil exploration report

2-shallow foundation

i-ultimate bearing capacity

Terzaghi theory

ii-general bearing capacity

iii-bearing capacity factors

iv-modification of bearing capacity equations for water table

3-foundation of special cases

i- foundation on rigid base at shallow depth

ii-bearing capacity for layered soils

stonger soil underlain by weaker soil

bearing caoacity of foundation on top of slopes

4-bearing capacity and foundation settlement

i-stess incease in soil below loaded area.approximate method for stres increase

ii-elastic settlement using theory of elasticity

iii-primary consolidation settlement

iv-secondary comression

v-field load test

vi-tolerable settlement of buildings

5-mat foundation

i-combined foundations

ii-raft foundations

iii-settlement of mat foundations

elastic and consolidation settlement

iv-compensated foundations

6-retaining walls

i-lateral earth pressure

Rankine,s theory

Coulomb.s theory

ii-types of retaining walls

gravity wall,cantilever wall,counterfort wall

iii-stability of retaining wall against,overturning.stability,and bearing

capacity

iv-drainage of retaining wall

v-soil reinforcement

geotextile reinforcement,geogrid reinforcement

7-pile foundation

i-typesof piles,steel piles,concrete piles-plain concrete and reinforced

concretepiles-cast in place and precastpiles

timber piles

ii-pile installation

iii-load transfer mechanism

iv-pile load capacity,point bearing capacity,frictional resistance

for sandy and fine grained deposits

v-pile load test

vi-elastic and consolidation settlement of piles

vii-pile driving formuls

viii-negative skin friction

8-group piles

i-group efficiency

ii-load capacity of group piles in sandy and clayey deposites

iii-consolidation settlement of group piles

text book

principles of foundation engineering

by Braja M. Das

reference

foundation analysis and design

byJoseph E.Bowles

evaluation and grading

1-there will be two mid term exams each carries 20 percent

2-homework and quizzes 10 percent

3-final exam 50 percent

Final Exam Example

Time; 3 hours

First semester 1429/1430

Answer all questions

Question one

a) List types of field tests.Explain one of them in some details.

b)What is the difference between disturbed and undisturbed soil samples?

c) Define recovery ratio and rock quality designation.How to classify rock

according to RQD ?

d)What is the purpose of subsoil exploration?

question two

a) Define general shear failure, local shear failure, and punching shear

failure.Illustrate your answer with neat drawing.

b) A rectangular foundation L=1.5 B is to be placed at depth1.5m in

soil which has unit weight of 17 kn/m3 and saturated unit weight

18.5 kn/m3, c=25 kn/m2 and angle of friction=22.The water table is at

1.0 m below the ground surface.Find the width B and lenth L of the

foundation if the applied load is 400 kn and FS=3.

Question three

a) A square foundation 2m by 2m is acted upon by a load of 300kn

a moment of 150kn.m.Calculate and draw the pressure distribution

below the foundation

b) Find the allowable bearing capacity of a square foundation;

1.5m by 1.5 m resting on stong sand, unit weight of 18.5kn/m3

and angle of friction=35 underlain by soft soil with c2=50 kn/m2 and

angle of friction=0 assuming fs=3

for two cnditions;

1-sand layer thicknessis2m,and

2-sand layer thickness is 1m.

Question four

a) What are the types of settlement? Explain one of them in some

details.

b) Asquare foundation 2m by 2m is placed on a soil profile as shown

below. Find the allowaple bearing capacity assuming the failure

surface is within the sandy layer. FS=3

c) Calculate the consolidation settlement in the silty clay layer. Use

the approximate method to find delta segma z

Question five

a) What the types of retaining walls? Draw neatly each type.

b) A cantilever retaining wall is as shown below. Determine

the factor of safety against overturning,sliding,and bearing

capacity.

Question six

a) Expain how to install a pile into the soil. What are the different

methods that are used for this purpose?

b) Compare steel pile with reinforced precast pile.

c) A precast concrete pile is driven into soil , the profile of

which is shown in the fihure below. Calculate the pile load

capacity( frictional resistance and end bearing). assume F IS 4

Typical Mid -Term Exam

Question One

(a) What are the purposes of soil exploration program?

(b)Explain the Standard Penetration test .Use neat drawing to illustrate your answer. What are the type of samples obtained from this test?

(c) Draw the piston sampler.Compare this sampler with thin-walled tube sampler in obtaining undisturbed soil samples

(d)Define the rock recovery and RQD in rock sampling.

(e) Prepare a borehole log indicating all the necessary information that should be included.

Question Two

a) What are the assumptions used by Terzaghi in the bearing capacity theory?

b)A rectangular foundation (2mby2m) is to be established on a soil at a depth of 1 m below the ground surface .Find the allowable colmn load that can be applied to the foundation using the folowing data

Dry unit weight 16.8 knlm3 saturated unit weight is 18.2 knlm3,cis 25 knlm2 angle of friction 24

(Note use the general bearing capacity equation assuming the water table is at the base of foundation Use FS 3.

Question Three

a) Draw the different types of pressure distribution beloww an eccentrically loaded foundation .What is the pressure distribution mostly acceptable and why?

b)Find the alloable bearing capacity of a rectangular foundation (Bis 1m L is 2M) located at depth 1m below the ground surface for stronger saturated clay underlain by weaker saturated clay located at a depth H of .75m measured from the bottom of foundation

Top layer c is 150 knlm2

unit weight is 18.1

Bottom layer

c is 50knlm2

unit weight is 16.2.

.