Experimental and statistical study on the behavior of bounded foundation on sandy soil

Dissertant

Muhammad, Hisham Ata Allah

Thesis advisor

Fattah, Muhammad Yusuf
Shallash, Qays Taha

University

University of Technology

Faculty

Building and Construction Department

University Country

Iraq

Degree

Master

Degree Date

2012

English Abstract

Structural skirts are walls fixed to the edges of shallow foundations to improve their bearing capacities.

Sometimes, the shallow foundation is bounded by a close obstruction like a wall.

The presence of this wall has an effect on the bearing capacity of footing, whose behavior in this case can be similar to a skirted foundation in which a structural skirt is located at one side of the footing.

The present study investigates the behavior of model footings bounded by a wall of different depths and located at different distances from the footing, resting on sandy soil.

In this study, different parameters are considered such as shape of footing (square, rectangular and strip) with dimensions (60*60, 60*100 and 60*300) mm respectively, relative density of sand (33, 56 and 75) %, distance from of wall to the edge of footing to width of footing ratio (h/B) (zero, 0.5, 1, 1.5 and 2) and depth of wall to width of footing ratio (d/B) (0.5, 1, 1.5 and 2).

A total number of 153 models for three shapes of footings with three relative densities of sand (33, 56 and 75) % are divided into two groups according to the testing program.

Firstly, tests on model footings (without wall) are carried out.

Secondly, tests on model footings (with a wall) are carried out.

Test results show that the presence of the wall affects remarkably the values of bearing capacity, leading to improvement in the values of bearing capacity with different percentages according to the distance from wall to the edge of footing to width of footing ratio (h/B) and depth of wall to width of footing ratio (d/B), due to the increase in soil confinement underneath the footing.

In loose sand, the largest improvement in bearing capacity for square, rectangular and strip footings bounded by walls reach (43, 34 and 37) %, at (h/B = 0.5) and (d/B = 2).

In medium sand, the largest improvement in bearing capacity for these footings bounded by walls reach (56, 33 and 25) %, at (h/B = 0.5) and (d/B = 2), while in dense sand, the largest improvement in bearing capacity for square, rectangular and strip footings bounded by walls reach (67, 52 and 59) %, at (h/B = 0) and (d/B = 2).

The bearing capacity increases with depth of the wall, the maximum effect of the wall on the bearing capacity is when the value of the depth of the wall (d/B) is between (1.5-2.0), for footings on sand of different densities.

The largest reduction in the vertical settlement in loose sand is about (88, 58 and 50) % for (square, rectangular and strip) footings, respectively.

In medium sand, the largest reduction in the vertical settlement for these footings is (150, 50 and 40) %, respectively.

In dense sand the largest reduction in the vertical settlement for the same footings is (160, 95 and 70) %, respectively.

Finally, three statistical equations are derived to predict the ultimate bearing capacity of square, rectangular, and strip bounded footings which represent relationships between the model footing ultimate bearing capacity with a wall, as a function of ultimate bearing capacity without wall, distance of wall from the edge of footing (h/B), depth of wall (d/B), dry unit weight (γd) and angle of internal friction ( ) of the soil.

The coefficient of determination (R2) is (99.1, 99.4 and 99.48) % for model (square, rectangular and strip) footings, respectively.

General statistical equation for predicting the bearing capacity of footings bounded by walls is derived by inserting length to width of footing ratio (L/B).

The coefficient of determination (R2) was (97.84%).

Main Subjects

Civil Engineering

Topics

• Construction engineering
• Freemasonry
• Mechanics
• Soil physics
• Soil mechanics
• Architectural engineering
• Walls

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-420082