TITLE:
Effect of Bearing Capacity on Designing Foundations in Iraq Using STAAD Pro-v8i
AUTHORS:
Entidhar Al-Taie, Nadhir Al-Ansari, Sven Knutsson
KEYWORDS:
Bearing Capacity, Soil, STAAD Pro., Laboratory Tests and Foundation
JOURNAL NAME:
Engineering,
Vol.6 No.6,
May
13,
2014
ABSTRACT: Most of Iraqi soil
is classified as Quaternary deposits, especially in the Mesopotamian plain and
tributaries of the River Tigris. Soil varies from north to south of Iraq. These
differences in soil affected the process to select the suitable type of
foundation. This research is to study the effect of bearing capacity on shallow
foundations in different regions of Iraq. Seventy nine samples were collected
from 23 boreholes at three different locations (Mosul at the North, Baghdad at
the middle and Basrah at the south of Iraq). The samples were collected at varying
depth between 1 to 24 m. They were subjected to the following testes: Atterberg
limits, sieve and hydrometers, consolidation, direct shear, unconfined
compression and the filed (SPT test). The values of the bearing capacity
parameters ( and c) were obtained from the above tests. The results obtained
were used in the application of the general equation of the bearing capacity.
Then, the model of a building was designed (two floors, with mat foundation
type) using STAAD Pro software. The average values of bearing capacity in each
region were applied in the program (Mosul = 177 KPa, Baghdad = 125 KPa and
Basrah = 84 KPa). In addition, the worst bearing capacity values were also used
for the three regions (Mosul = 77 KPa, Baghdad = 68 KPa and Basrah = 24 KPa).
The results obtained from the average and worst bearing capacity indicated that
for Mosul, we could use shallow foundation (spread and mat used if there was
basement) for different areas and for buildings with many stories. For Baghdad
region, shallow foundation was more suitable for building not higher than five
stories. Finally, for Basrah region, shallow foundations were an appropriate
selection, but for most areas deep foundation was the right choice.