Soil Structure Interaction Of Pile Foundation During Seismic Events (Dissertation Sample)

SOIL STRUCTURE INTERACTION OF PILE FOUNDATION DURING SEISMIC EVENTS
NAME
Abstract
This paper is based on the behaviors of pile foundation during the seismic events which tend to alter or change the pile foundations. The paper has also outline the effects of the seismic events like earthquakes on the pile foundations. The big and heavy loads induced by the events tend to damage the pile foundation of any structure as it has been outlined by recent studies. Since these areas are has experienced lack of enough and detailed studies and researches, this paper provides a deep outline of the effects of the seismic events. In the introduction, the paper has given the frequency with which the pile foundations have been used by engineers in recent times and how they account for the soil structure which brings a complex area of study and research. The paper has also given the contributions provided by the researches in the study of soil structure which is one of the most important fields when putting up a structure, building or road or bridge. In the methods, the paper has given a brief review of the previous studies which have been done before on the same area of study. Since literature review provides a basis for further research, this paper has given the findings of other studies. It has outlined the conclusions of those researchers and the challenges they faced during their research. The methodologies used in their studies have also been outlined in the methodology part of this paper. In the discussion section, the paper has given a brief outline of seismic lateral loads are generated and how the transfer of these loads has occurred at the interfaces of soil structures. The study has also given the techniques which have been used generally to represent the soil structures and those techniques which have been specific to piles and pile groups. The different methods for both single files and a group of piles (cap) have listed in the discussion section. A detailed discussion of each method is provided and the strengths of each outlined method. The methods for the effective representation of the soil structure interaction in general have been discussed. The outlined methods are, the thin layer method and the boundary element method and discussed in details. The lack of accuracy in these techniques in representing soil structures interaction in the occasion of a seismic event has been discussed in details, the problems and shortcomings involved in each method have been analyzed in this section. There have been difficulties in the effective use of the current techniques to effectively represent the soil structure interactions during a seismic event have also be discussed in this section of the paper. The paper has also outline the challenges faced by engineers and other professionals in the field in the use of these techniques and the need for more robust techniques which would be more effective in representing soil structure interactions in the event of a seismic occurrence. The groups of piles also have been analyzed and the difference they have in the transfer of lateral loads in the occurrence of a seismic event. The transfer of lateral loads in pile groups has been analyzed and the calculations and modifications of the methods of analysis to capture this have been done. The paper gives the weaknesses of the outline methods where there many assumptions made in the analysis methods. There are also lack of theoretical proofs and robustness of the methods which is a great challenge in applications. Some methods are only applicable in the soil from which the load tests were made in coming up with the given method. Recommendations for further research a have been made after identifying the weakness and the research gaps in the previous studies on the area of study. The study recommends further research on the methods used to represent effectively the soil interaction during the seismic events. The methods should take into account modern developments and more tall and strong structures not forgetting the issue of land reclamation.
Introduction
With the growing technology in the world and the faster economic growth in countries, the construction of structures has been on the rise in a daily basis. These structures include, buildings which we have witnessed the construction of story buildings with over 450 m high, there are also modern rails which have been constructed to accommodate stronger and heavier trains for easies transport of goods. These rails have called for stronger bridges despite the soft soil structures along the river banks where some of these bridges have been put into place. The construction of more roads has also been on the rise mostly in developing countries where we cannot fail to talk about the construction of bridges. Most of these outlined structures have been built regardless of whether the place of country is prone to seismic events. Due to these events and structures the use of pile foundations has a been an everyday talk. To support the structure especially in the seismic event prone areas, the use of pile foundations have been put into place. These pile foundations have been designed by engineers to resist the inertial force generated by the seismic events which lead to the damage of soil structures hence damaging the given structures which has led to the collapse of the many buildings and bridges in such an activity. This has in turn led to deaths of many people once such an event like earthquake occurs. To account for the soil structure which has been a complex topic due to the both linear and non linear interactions, engineers have been able to carry out both linear and non linear seismic analyses. The engineers have also been able to use the pseudo static analysis to do the pile analysis and also study of the forces generated by seismic events.
There have several contributions to the study of soil structure interaction and how the study could help reduce the effects of seismic events. Since these events have led to the weakening of soils structure hence the ground is unable to support such buildings such occurrences, the structures eventually collapse hence raising studies and contributions to the study. The introduction of the pseudo static analysis has been a major contribution to the study. The method although takes into account the uncertainties involved in soil structures, it is very simple to understand and also static (Misko Cubrinovski et al, 2010). The use of this simple method to model or analyze a complex event like the soil interactions have raised many questions hence could not be adequate or significant in the analyses.
Samridhi Singh et al (2015), in their journal called international journal of research in engineering and technology carried out a research on the effects of seismic events such as earthquakes on the foundations of the structures which have been put into place with the recent modernization. They concluded that the effects of a seismic event on the foundation of a structure are determined by the type, nature and behavior of soil in the affected area. They also concluded that, in the case where there is a soft soil where the foundation has been built, the whole structure may collapse in the event of an earthquake. They recommended some ways in which the effects of these seismic events can be minimized or prevent the collapse of the structures. They recommended that the given structure may be built like a single structure together with its foundation. These would help reduce the effect of the earthquake though not to a greater extend. They also proposed that the structure be built and floated above the foundation of the structure. This method is called the isolation. This method was also proven not to be very effective since we still experience the failure of buildings very often in the event of seismic activities.
Poulus H and Tabesh A (2006), in their study on some important factors which affect seismic response of pile foundations, gave a brief outline on the factors which affect the response. In their study they proposed and approach where they used parameters like, the pile and elasticity of soil, length of pile, the diameter of pile and the mass of cap. Their method was proven to be effective due to its ability to capture time domain making the non linear seismic analysis easy and applicable. The method also was also clear in making assumptions made easy to understand. Although the method had the above mentioned strengths it also had a weakness of making too many assumptions in the analysis of the seismic response of the pile foundations. These assumptions were made due to use of many parameters which are mathematically involved with many assumptions hence making the method not reliable since all the assumptions have to be proven. Some of the assumptions are deemed not to be true at the end of the analysis. So their method had the loophole of many assumptions.
Puri V and prakash S (2008) in their paper on the 14th world conference on earthquake engineering provide methods for pile design in liquefying soils. They stipulated that the strength of soil decreases when there is an increase in the pore water pressure in the soil. These leads to the loosening of structures and pile foundations put into place on that particular soil. They gave the methods which provide a reliable design of pile foundations in these loose soils, they propose the force or limit equilibrium analysis as one of the methods and p-y analysis which is also called the displacement analysis. Their method for force based was used using the experience of the past earthquakes experienced I their area. They however concluded that the given methods needed further study since there were no any given solutions which would be satisfactory to the study of soil interaction in seismic events. Since their study was used the case of chine, it could not be generalized to the ot...