It will Helps you to know about Bearing capacity and Shallow Foundation.

1. MEHRAN UNIVERSITY OF ENGINEERING AND TECHNOLOGY,
SHAHEED ZULFIQAR ALI BHUTTO CAMPUS KHAIRPUR
MIRs’
DEPARTMENT OF CIVIL ENGINEERING
Name: Faizan Noor
Roll No: KF16CE-56
Subject: Foundation Engineering (CE426)
Teacher: ENGG: Hemu Karira
Date of exam: 22-07-2020
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2. PBL presentation topic
Bearing Capacity of Shallow Foundation.
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3. Bearing Capacity of Soil.
Bearing capacity is the capacity of soil to
support the loads applied to the ground.
The bearing capacity of soil is the maximum
average contact pressure between the
foundation and the soil which should not
produce shear failure in the soil.
Bearing Capacity(Units).
The sign of Bearing Capacity (B.C) and this
units as pressure's unit ton/m2, KN/ m2,
Kg/cm2, lb./ft2 etc.… so can called Bearing
Pressure
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4. Shallow Foundation.
A shallow foundation is a type of building foundation that transfers
building loads to the earth very near to the surface, rather than to a
subsurface layer or a range of depths as does a deep foundation.
Shallow foundations, often called footings, are situated beneath the lowest
part of the structure. A footing is the first constructed element of a
structure which is built after excavating the ground.
In general, the depth of a shallow foundation is less than its width.
Shallow foundations are commonly used as they are the most economical
foundation system and are relatively easy to construct. A careful
investigation of the foundation site and detailed information of the
subsurface stratum is necessary to design the foundation and avoid any
future degradation of the foundation performance.
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5. Bearing Capacity of shallow
foundation.
The bearing capacity of a shallow foundation can be defined as the
maximum value of the load applied, for which no point of the subsoil
reaches failure point.
A foundation is required for distributing the loads of the superstructure on
a large area.
The foundation should be designed such that
a) The soil below does not fail in shear
b) Settlement is within the safe limits.
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6. • Ultimate bearing capacity (qu):
• Ultimate bearing capacity is the theoretical maximum pressure which can
be supported without failure
• Net ultimate Bearing Capacity (qnu) or (ovrbruden pressure):
• It is the net increase in pressure at the base of foundation that cause shear
failure of the soil. Thus,
• qnu = qu – γDf
• Net Safe Bearing Capacity (qns) :
• It is the net soil pressure which can be safely applied to the soil considering
only shear failure Thus,
• qns = qnu /FOS
• Gross Safe Bearing Capacity (qs) :
• It is the maximum pressure which the soil can carry safely without shear
failure
• qs = qnu / FOS + γ Df
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7. Terzaghi's Bearing Capacity Theory
• Terzaghi was the first to present a comprehensive theory for the evaluation of the
ultimate bearing capacity of rough shallow foundations. This theory states that a
foundation is shallow if its depth is less than or equal to its width. Later
investigations, however, have suggested that foundations with a depth, measured
from the ground surface, equal to 3 to 4 times their width may be defined as
shallow foundations.
 For Square Footing.
• 𝑞 𝑢𝑙𝑡 = 1.3𝑐′ 𝑁𝑐 + 𝜎𝑧𝐷
′
𝑁𝑞 + 0.4𝛾′ 𝐵𝑁𝛾
 For Continuous Footing.
• 𝑞 𝑢𝑙𝑡 = 𝑐′
𝑁𝑐 + 𝜎𝑧𝐷
′
𝑁𝑞 + 0.5𝛾′
𝐵𝑁𝛾
 For Circular Footing.
• 𝑞 𝑢𝑙𝑡 = 1.3𝑐′
𝑁𝑐 + 𝜎𝑧𝐷
′
𝑁𝑞 + 0.3𝛾′
𝐵𝑁𝛾
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