Post on 17-Mar-2018
School of Environmental School of Environmental School of Environmental School of Environmental Engineering, Engineering, Engineering, Engineering, UniversitiUniversitiUniversitiUniversiti Malaysia Malaysia Malaysia Malaysia
Perlis, MALAYSIAPerlis, MALAYSIAPerlis, MALAYSIAPerlis, MALAYSIA
Analysis of Raft Foundation with EPS Analysis of Raft Foundation with EPS Analysis of Raft Foundation with EPS Analysis of Raft Foundation with EPS Geofoam for Earthquake ResistantGeofoam for Earthquake ResistantGeofoam for Earthquake ResistantGeofoam for Earthquake Resistant
Presenter : Mohd Faiz Mohammad Zaki
World Virtual Conference on Advanced Research in Materials andEngineering Applications
Content of Presentation
Material and Methodology
Test Method
Results and discussion
Conclusion
Introduction
A major earthquake produces a strong
ground motion in the subsoil and surface
structures supported on the soil mass will be induced to move and absorb the dynamic
forces.
INTRODUCTION EARTHQUAKE
Building foundations working satisfactorily
under static loading may be affected when the
shear stress in the subsoil induced by the
earthquake added to the already existing static
shear stresses reach the shear strength of the soil. This lead for the failure
of foundation.
INTRODUCTION Earthquake
INTRODUCTION EPS
Innovative material such as Expended Polystyrene (EPS)
Geofoam is widely accepted in structural engineering due to its characteristic to absorb the
dynamic force effectively.
It is becoming a great challenge for civil engineers to design a
foundation with able to restrain from an earthquake.
Expanded Polystyrene (EPS) is a super-lightweight, closed cell,
rigid and also plastic foam.
INTRODUCTION EPS
INTRODUCTION EPS
EPS is not a common soil fill replacement materials but invented indirectly to solve geotechnical engineering
challenges.
The used of EPS typically translate into benefits to construction schedules and lower the overall cost of construction because it is easy to handle during the
construction.
This research focused on the application of EPS in mitigating the earthquake forces, particularly
for raft foundations.
INTRODUCTION Objectives
The settlement that occurred beneath the foundation is analyzed and recorded through this research
The various types and thickness of EPS located beneath the raft foundation and over the soft soil are
studied.
Table 1Table 1Table 1Table 1: Clay properties
Material and Methodology
The finite element program was used for this research.
The material properties of EPS Geofoam used for this study as given in Table below.
Material and Methodology
Material and Methodology
Simulation of raft foundation and EPS geofoam has shown in Figure below.
This result based on earthquake analysis and immediately after 30 second of the earthquake occurrence, the reading was recorded for the vertical displacement at Point C and D. Graph for vertical
displacement versus time is taken at Point C since it has contributed the significant effect towards the stability of the
foundation
TEST METHOD
RESULTS AND DISCUSSION - (without EPS)
Based on the graph, there is a significant change of displacement at point C starting at the first moment. The value is 1.8 mm and after 2 second, the displacements value became constant. For point D, changes in displacement can considered as constant since it is resulted in insignificant changes. It can be concluded from the
analysis that the foundation was tilt and unstable.
RESULTS AND DISCUSSION – (with EPS19)
According to the pattern graph above, EPS located beneath the raft foundation provide a good result in maintaining the stability of the foundation. EPS19 with thickness of 1 m able to reduce the vertical
displacement while comparing to the other thicknesses.
RESULTS AND DISCUSSION – (with EPS22)
By referring to graph above, EPS located beneath the raft foundation provide a good result in maintaining the stability of the
foundation. EPS 22 with thickness of 1 m able to reduce the vertical displacement while comparing to the other thicknesses.
RESULTS AND DISCUSSION – (with EPS29)
Result for EPS29 as shown in Figure above. The pattern of this result is similar to EPS19 and EPS22 where the same thickness of 1 m presents the minimum settlement value compared to EPS19 and
EPS22. The vertical displacement by using this type of EPS is approaching 0 mm. The actual maximum value is 0.05 mm.
Conclusion
Conclusively, Expended Polystyrene (EPS) Geofoamthat placed beneath the raft foundation and exposed to earthquake loading is able to produces the minimum
settlements rather than raft foundation modeled without EPS.
Based on the results, increasing the density of EPS will decrease the settlement of a foundation.