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.