Design of foundation for nablus industrial coed school

An-Najah National University

Engineering College

Civil Engineering Department

Design of Foundation forNablus Industrial School""

Submitted bySameh Jamal Zalmout

SupervisorDr. Sami Hijjawi

Introduction to Foundation

A foundation is a structure that transfers loads to the earth.

Foundations are generally broken into two categories

Types of Foundations

1 -Shallow Foundation

2 -Deep Foundation

Shallow Foundation

1 -Spread Footing

2 -Mat Slab

3- Slab on grade

Deep Foundation

2-Pier and grade beam foundation

1-Pile foundation systems

3-Specialty piles

Specialty Piles

1-Micropiles

2-Tripod piles

3-Sheet piles

4-Soldier piles

5-Suction Piles

6-Vibro Stone Columns

7-Piled walls

8-Pipe piles

12-Screw Piles

11-Timber Piles

10-Cylinder Piles, (hollow concrete piles)

9-Pre-stressed concrete piles

13-Platform on Piles

Project Description andGeotechnical Investigation

-The school consists 4 stories

-Plan construction area 606-1053 square meter in the first and second basement, and 902 square meter in the ground and first floors

-No ground water within the depth of the borehole

-6 boreholes

-The soil is high plastic silty clay layer

-The studied area is flat

ElevationSoil type

Depth(m)

B(m)

L(m)

C(KN/m2)

Ø(t/m3)Bearing

capacity(kg/cm2)

104.5(BH.1-4)

Silty Clay (CH)2.03.02.0361061.6

102.0(BH.4)

Marl2.03.02.03310201.8

106.0(BH.1-6)

Marl+gravel2.03.02.01221202.5

103.0(BH.3-2-5)

Silty clay(CH)

4.03.02.0301261.7

99.0(BH.1-4)

Marl+gravel5.53.02.0923184.7

Structural Analysis

Gravity loads divided into 2 types;

Dead Load (D.L)

Live Load (L.L)

Service load=1.2 D.L+1.6 L.L

D.L= Area (around column)*Slab thickness*Density of the concrete

Thickness of slab =0.4 meter

Density of the concrete =2500 Kg/m³

L.L= 600 Kg/m³

Mat Foundation

Mat foundation is a combined footing that may cover the entire area under a structure supporting several columns

and walls

Mat foundations are sometimes preferred for soil that have low

bearing capacity

The project consists of two

symmetrical mat foundation

The following figure shows the mat foundation (using sap2000 version 12)

Mat depth= 0.75 meter

!Fc =280 kg/cm²

Fy = 4200 kg/cm²

Column height = 3.5 meter.

Pile Foundation

Piles are long and slender members which transfer the load to deeper soil or rock of

high bearing capacity avoiding shallow soil of low bearing

capacity

Single Pile

The ultimate load can be carried is equal to the sum of ultimate resistance of the base of the pile and the ultimate skin friction over the embedded shaft

of the pile

Qs= (∑ (F*Cu*P))*ΔL

qp = Nc * Cu

Qp= qp*Ap

Q allowable= 3

Qs Qp

All piles used in this project was (0.7,0.8) meters diameter with

several lenghts

Total number of piles

105 piles

Settlement of piles

Se = Se (1) +Se (2) + Se (3)

Se (1) = elastic settlement.

Se (2) = elastic settlement due to load at pile tip.

Se (3) = elastic settlement due to skin friction (shaft)

Pile Caps

Pile Cap is defined as a concrete block cast on the head of a pile to

transmit the load from the structure to the pile or group of piles.

According to the nature and characteristics of the materials

encountered in the drilled boreholes (Fill materials with well

defined layers of high swelling silty clay at a shallow depth followed by marlstone and

occasionally boulders) ,

as well as the low soil bearing capacity, I suggest to consider the design of pile foundations for the building to reduce or avoid the detrimental effects of soil volume change (swelling and shrinkage) along the bored depth of the boreholes

Thank You