Pile Foundation Calculation Report of
Cargo Terminal (1-5-1)
Nasiriyah International Airport
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Table of Contents
1.0
Project Overview _____________________________________________________________ 3
2.0
Code and Standard ___________________________________________________________ 4
3.0
Design of Single Pile Compressive Bearing Capacity _______________________________ 4
3.1 Calculation Method ____________________________________________________________________ 4
3.2 Onsite Pile Load Test _________________________________________________________________ 10
4.0
Design of Single Pile _________________________________________________________ 11
5.0
Design of Pile Group Capacity _________________________________________________ 13
6.0
Calculation of Modeling _______________________________________________________ 14
6.1 Bearing Stratum ______________________________________________________________________ 17
6.2 Column Base Reaction Forces _________________________________________________________ 18
6.3 Working Loads _______________________________________________________________________ 19
6.4 Punching Shear DC Ratios ____________________________________________________________ 34
6.5 Reinforcement Result _________________________________________________________________ 37
7.0
Design of Lateral Bearing Capacity _____________________________________________ 38
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7.1 Single Pile ___________________________________________________________________________ 38
7.2 Group Effect _________________________________________________________________________ 42
1.0 Project Overview
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Based on the Geotechnical Investigation Report, the foundation type of the project structure is the
piling foundation under the column. The layer ④ Silty Sand is chosen as bearing stratum for piles.
2.0 Code and Standard

Geotechnical Investigation Report of Airside and Landside for Nasiriyah International Airport
Project (Both Preliminary and Details Reports)- 02/10/2022.

Design And Construction Of Driven Pile Foundations（FHWA NHI-05-042）

Guide To Design, Manufacture, and Installation Of Concrete Piles（ACI 543R-2012）

Standard Test Methods For Deep Foundations Under Static Axial Compressive Load（ASTM
D1143/D1143M-07）

Minimum Design Loads for Building and Other Structures (ASCE/SEI7-16)
3.0 Design of Single Pile Compressive Bearing Capacity
3.1 Calculation Method
The ultimate bearing capacity of piles was calculated according to Section 9.3 of the American
Standard FHWA-NHI-05-042-Volume I "Design and Construction of Driven Pile Foundations"(as
shown in the following figure)
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According to Section 9.6 of the American standard FHWA-NHI-05-042-Volume I "Design and
Construction of Driven Pile Foundations" (as shown below), the safety factor is 2.
According to section 12.2 of The Nasiriyah International Airport Project-NIAP Geotechnical
Investigation Report For Landside Area [Detailed]-2022.7.14, Layer ⑤ silty sand and Layer ④ are
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recommended as pile end bearing stratum, and the side resistance and tip resistance of different
soil layers can be known.
Referring to the pile penetration depth of the test pile test, the minimum value of the penetration
depth of 16.65m (excluding the length of the pile tip) is selected as the reference for the design pile
length, so the design pile length is selected as 16.5m.
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Exploration Boreholes Layout for Cargo Terminal from Geotechnical Report
According to the geological survey report, the soil layer of the main terminal building is relatively
uniform, so the following six relatively unfavorable points are selected to calculate the design
bearing capacity of the single pile (as shown in the figure below). The average single pile design
bearing capacity (1065KN) of the above six points is selected as the final single pile design bearing
capacity.
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Single pile design bearing capacity of survey point BH271
(16.5m excluding pile tip length)
Single pile design bearing capacity of survey point BH273
(16.5m excluding pile tip length)
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Single pile design bearing capacity of survey point BH277
(16.5m excluding pile tip length)
Single pile design bearing capacity of survey point BH280
(16.5m excluding pile tip length)
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Single pile design bearing capacity of survey point BH281
(16.5m excluding pile tip length)
Single pile design bearing capacity of survey point BH282
(16.5m excluding pile tip length)
3.2 Onsite Pile Load Test
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The static axial pile compressive load test had carried out by Compass Company for precast
concrete piles with dimensions 40x40cm and totally 5 piles. The conclusion as shown below from
the test report.
Based on the two methods which are calculation and load test onsite, the design bearing capacity is
1036kN. The penetration of pile length used in the calculation is 16.5m and the average penetration
of pile length is 16.32m for 5 piles in the load test onsite. However, based on the fact that the pile
head need to be connected with the upper concrete cap. Therefore, the reference pile length is
18.6m which can meet the design bearing capacity requirement. (A complete pile length is 12m and
half is 6m, plus 0.6m pile tip, totally 18.6m)
4.0 Design of Single Pile
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The design requirement for precast pile from IBC 2018 as shown below:
The design of single precast pile is the 400x400mm square section. For Cargo Terminal, the
seismic design category is C. Therefore, the minimum longitudinal reinforcement ratio shall be 0.01.
8d20 which is greater than the minimum longitudinal reinforcement ratio as longitudinal
reinforcement in the design of single pile. The compressive strength of concrete cube is 40Mpa for
single pile and the design compressive strength of single pile is 3056kN and comply.
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5.0 Design of Pile Group Capacity
For the Cargo Terminal, all the piles for the structure are installed in groups due to the foundation
loads. According to the American Standard of FHWA-NHI-05-042-Volume I "Design and
Construction of Driven Pile Foundations”, the calculation method of ultimate capacity of the pile
group as shown below.
Layer ④ , as pile end bearing stratum, is cohesive and compressible clays based on the
Geotechnical Report. According to FHWA-NHI-05-042-Volume I "Design and Construction of Driven
Pile Foundations”, the pile group efficiency is determined as followings.
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Based on the laboratory test of Layer ④, the undrained shear strengths is less than 95 kPa, and
the pile cap in firm contact with the group by grade beams. Therefore, the group efficiency of 1.0 is
used, and the ultimate capacity of the pile group = number of piles in the pile group x ultimate
capacity of each individual pile in the pile group x 1 (pile group efficiency).
6.0 Calculation of Modeling
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Modeling of foundation by software of “COMPUTER & STRUCTURES, INC.” named SAFE。Forces
calculated by ETABS at bottom of columns in all cases can be import into SAFE to calculate
foundation accurately. The contents will be displayed according to the sections on the figure as
shown below.
Section
1
Section
2
Model of Foundation
One of columns’ bottom forces is shown as follows as an illustration:
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One of Columns’ Bottom Forces
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6.1 Bearing Stratum
According to GEOTECHNICAL INVESTIGATION REPORT FOR LANDSIDE AREA(detailed),
choosing layer ④ as the bearing layer.
Foundation Recommendation Table from Geotechnical Investigation Report
Test parameter statistics of layer ④ are shown in the following table from geotechnical
investigation report.
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Test Parameter Statistics of Layer ④ From Geotechnical Investigation Report
6.2 Column Base Reaction Forces
The reaction forces at column base under the maximum load combination as shown below:
Section 1
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Section 2
6.3 Working Loads
The design load bearing capacity of each pile is 1036kN. Based on IBC 2018 1605.3.1 and ASCE
7-16 2.4. The load combinations as shown below for calculation.
After the calculation, the results of actual working load under the load combinations as shown below
for each pile.
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D+L:
Section 1
Section 2
The maximum working load on the pile is 809.25kN which is less than 1036kN and safe.
D:
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Section 1
Section 2
The maximum working load on the pile is 717.31kN which is less than 1036kN and safe.
D+0.75L:
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Section 1
Section 2
The maximum working load on the pile is 834.65kN which is less than 1036kN and safe.
D+0.6WX:
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Section 1
Section 2
The maximum working load on the pile is 749.65kN which is less than 1036kN and safe.
D+0.6WY:
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Section 1
Section 2
The maximum working load on the pile is 777.62kN which is less than 1036kN and safe.
D+0.7EX:
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Section 1
Section 2
The maximum working load on the pile is 738.07kN which is less than 1036kN and safe.
D+0.7EY:
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Section 1
Section 2
The maximum working load on the pile is 768.12kN which is less than 1036kN and safe.
D+0.75L+0.45WX:
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Section 1
Section 2
The maximum working load on the pile is 834.64kN which is less than 1036kN and safe.
D+0.75L+0.45WY:
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Section 1
Section 2
The maximum working load on the pile is 855.62kN which is less than 1036kN and safe.
D+0.75L+0.525EX:
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Section 1
Section 2
The maximum working load on the pile is 837.71kN which is less than 1036kN and safe.
D+0.75L+0.525EY:
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Section 1
Section 2
The maximum working load on the pile is 847.53kN which is less than 1036kN and safe.
0.6D+0.6WX:
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Section 1
Section 2
The maximum working load on the pile is 449.79kN which is less than 1036kN and safe.
0.6D+0.6WY:
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Section 1
Section 2
The maximum working load on the pile is 477.76kN which is less than 1036kN and safe.
0.6D+0.7EX:
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Section 1
Section 2
The maximum working load on the pile is 451.47kN which is less than 1036kN and safe.
0.6D+0.7Ey:
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Section 1
Section 2
The maximum working load on the pile is 466.98kN which is less than 1036kN and safe.
6.4 Punching Shear DC Ratios
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Punching shear results are displayed as a ratio of maximum calculated shear with respect to
capacity.
The ratio is displayed for each column and each point load.
Section 1
Section 2
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A ratio above 1.0 would indicate that capacity was exceeded somewhere along the critical section.
A ratio below 1.0 would indicate that capacity was not exceeded and safe. All the results of the
punching shear DC ratio are less than 1.0 and safe.
One of columns’ punching shear DC calculation report is shown as follows as an illustration.
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Load Combination for Punching Shear Design
6.5 Reinforcement Result
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Plan Strip Design – Layer A - Bottom Reinforcement Intensity （impose minimum reinforcing）
(Enveloping Flexural)[m2/m]
Plan Strip Design – Layer B - Bottom Reinforcement Intensity （impose minimum reinforcing）
(Enveloping Flexural)[m2/m]
7.0 Design of Lateral Bearing Capacity
7.1 Single Pile
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The DAC which is company that provided the geotechnical report has issued the additional
information about the horizontal bearing capacity of the file foundation as shown below.
For the Cargo Terminal, the foundation is the precast pile by 400mm diameter which the lateral
allowable bearing capacity is 161KN (fixed).
According to the IBC 2018 as shown below, only the seismic design categories D through F on site
class E or F shall be designed and constructed to withstand maximum imposed curvatures which is
horizontal displacement from earthquake ground motions. But the Cargo Terminal is seismic design
category C and the site class is D. Therefore, it is not required by the code or standard that the
design need to consider the horizontal displacement, and the allowable lateral capacity can be
considered as fixed of pile.
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The horizontal seismic force calculated by the model under the load combinations which include X
and Y directions as shown below for each pile. All the lateral loads are less than the lateral
allowable bearing capacity for each pile.
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Lateral seismic load distribution under load combination shown in X-direction on each pile (KN)
The maximum lateral seismic load on each pile in X-direction is 35.89kN which less than the lateral
allowable bearing capacity and safe.
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Lateral seismic load distribution under load combination shown in Y-direction on each pile (KN)
The maximum lateral seismic load on each pile in Y-direction is 55.85kN which less than the lateral
allowable bearing capacity and safe.
7.2 Group Effect
Lateral load reduction values for front row and back row piles due to the group effect are shown
below. This table provide by DAC which issued the geotechnical report.
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Pile
# of
Soil
Type
Spacing
Rows
in
group
1st
2nd
3rd
4th
Trailing
Trailing
Trailing
Trailing
Row
Row
Row
Row
Leading
(Center
Row
to
center)
Clay
3
3.0d
0.82
0.68
0.58
/
/
Clay
3
5.65d
0.95
0.88
0.77
/
/
Clay
4
4.4d
0.90
0.80
0.69
0.73
/
Clay
5
3.3d
0.82
0.61
0.45
0.45
0.51
The table shows that 5 of rows in group with 3.3d of pile spacing (center to center), the minimum
reduction value of lateral load capacity of piles is 0.45. Actually, the pile spacing designed as 4d and
the minimum reduction value should be greater than 0.45. There is the typical sample of 10 piles
group to check the lateral load capacity.
Under load combination in X-direction:
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The allowable lateral bearing capacity for each pile is 161kN. After the minimum reduction, the
allowable lateral bearing capacity is 161x0.45=72.45kN which greater than 66.02kN in 2nd trailing
row and safe.
In fact, when considering the lateral load capacity due to group effect, the pile cap and piles work
together to resist the lateral load. Therefore, the current design is very conservative.
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