Paper presented at Arab Conference for Astronomy and Geophysics. Cairo, 17-20 October 2016.

1. Application of Integrated Geophysical Technique for
the mapping of old Foundation Pilings at Penang
Sentral,Butterworth, PulauPenangMalaysia.
Mohd Nawawi and Amin E. Khalil
PPSF, Universiti Sains Malaysia

2. • Problem statement
• Site Layout
• Planned Geophysical techniques
• Methods overview
• Survey layout.
• Results

3. Problem Statement
The site under investigation is planned for new
development project at Pulau Pinang state. 20 years ago
another project was established at the site. However, the
project as cancelled and the buildings were removed and
the foundations was buried. These buried foundation
piles decelerated the construction of the new project.
This is motivation of the present work.

4. Phase 1
Parking
Taxi
area
Bus area

5. The site is a connection center where various
land and marine transportation exist. These
facilities are:
1- The ferry that connects Penang island with
the mainland.
2- The railway station (KTM) that connect the
state with
other Malaysian states.
3- Rapid Penang bus station.
4- Asphaltic roads and a flyover bridge.
Ferry
R. Penang

6. Foundation Piles can be
detected through these
properties:
1. Density contrast.
2. Shear wave velocity.
3. Magnetic properties due to iron bars.
4. Resistivity
5. Dielectric constant

7. Hence the following
Methods was
proposed
1.Gravity.
2.Magnetic gradiometer
3.Multichannel Analysis of Surface waves.
4.Time domain electromagnetic
5.Ground Penetrating Radar GPR

8. CG-5
autograv
Although density contrast exist
between concrete piling and
surrounding soil, the area is too
noisy that we couldn’t carry out
a reliable gravity survey. As a
result the gravity method was
excluded from the survey

9. Preliminary test
showed good
results confirmed
by field
inspection.
Example in figure
shows high
anomaly at

10. MASW (Multichannel analysis of
surface waves).
Two problems when
test MASW at the
site. These
problems are the
high noise and low
resolution of the
method. Hence, the

11. GPR
The method gave good
result as shown in the
figure.

12. Methods Used
1- Magnetic Gradiometer
2- GPR

13. Magnetic Gradiometer
The technique uses
measurements from
two proton
magnetometer
aligned vertically at
a spacing of 1m. The
subtraction gives the
vertical gradient of
magnetic field. The
gradiant enhances
the near surface

14. GPR
The technique produce
profiles similar to
seismic reflection
profile. An
electromagnetic pulse is
sent to the subsurface,
the reflected energy
from anomalous
surfaces is then

15. Survey Layout
Grid points at 5m separation.

16. Results

17. Results (cont.)

18. conclusion
• Old foundation piling decelerate the
establishment of new development project
• Near surface geophysical methods were
employed to solve the problem.
• Magnetic gradiometer and GPR showed
good example for detecting old foundation
piles.
• Other methods couldn’t be applied because
of the site conditions

19. ‫جزيال‬ ‫شكرا‬
Terima Kasih
Thank you