Vietnam War :: essays research papers

Vietnam was a small Asian country, 9000 miles away from the United States. Yet America felt that its national interest was threatened strongly enough to fight a war there. The explanation for this lies in the fear caused by the spread of communism at that time. The role of communism was extremely important in this conflict. You see, the US had to enter the war to stop the spread of communism in Asia since North Vietnam was communist. If North Vietnam was to succeed in converting Vietnam into a communist country , it could become very powerful and go on to persuade other countries to become communist. The US believed that Vietnam could become powerful, and it was willing to go through anything to stop that, including sending millions of US troops to Vietnam and watching them die live on TV, and this greatly effected the American culture and society. The Vietnam war. It changed the lives of many people, and in many unfortunate cases eliminated those of others. "By the end of 1965, 184,314 troops were in Vietnam" (Internet), sacrificing their future, their lives. "Within a year, the number had grown to 385,000"(Internet). For those back in America, the hardship was felt as their sons died overseas. imagine waking up one morning and turning the local news of and seeing your son's face on the TV screen as one of the few hundred who died just last night. It was horrifying . All this effected American society greatly. Moms were losing sons, sisters were losing brothers, and children were losing dads. The Vietnam war had a harsh outcome. "More than 47,000Americans were killed in action,11,000 died of other causes, and 303,000 were wounded"(Internet). As more and more Americans continued to leave for Southeast Asia, the American people responded with disillusionment and it caused the American society to lose faith in the government ,as a series of powerful protests took place across the nation.Opposition to the Vietnam war in the United States developed immediately after the Gulf of Tonkin Resolution. Early protests were organized around questions about the morality of Us Military involvement in Vietnam. As each key event of the war occurred, the antiwar sentiment steadily rose. "Students and professors began to organize "teach-ins" on the war in early 1965 at the university of Michigan, University of Wisconsin, and the University of California at Berkeley"(Encarta). eventually, virtually no college or university was without an organized student movement.

African American Culture and Traditions

The African American Culture and Traditions A Research Study and Facts That Will Take Us Into What Makes This Culture So Unique. Jeanette C. Council Dr. Jefferson Rackley COUN 504 5 May 2012 Liberty University Abstract The purpose of this research is to identify the uniqueness and diversity of people and practices of the African American culture. Each culture in life has some similarities and some differences. The similarities and differences that are present in a culture is what make the culture what it is.When dealing with a culture, race, ethnicity, of a people or religion it has a history of where it originates and or a heritage that that culture or people can relate to and always go back to, because this is what sets a group apart from the next. We will look at the key factors that contribute to family patterns found in my family of origin, which is the Jewish culture. We will also compare and contrast the similarities and differences between my family origins, which is that of the African American origin. Introduction There are many cultural groups and ethnicities in the world.Each and every person has a background and culture in which they come from, derive, or exist into. We don’t have any control over whether or not we have one culture in our families or many, but that’s what makes us diverse or unique and that’s what gives us the culture African American, Jewish, Asian, or Latino. As I have read and researched many diverse cultures during this course, it has taught me a lot about culture and having respect for mine as well as anyone else’s. We define the word culture â€Å"as the totality of the human experience for social contexts.This experience is mediated by biological, psychological, historical, and political events. Culture also includes behaviors, attitudes, feelings, and cognitions related to our identities living within the world (Hays, 2010). † As I explore my background, I will then learn more about who I am and the beauty of the culture that I originate from. My Family Genogram As I looked into my family history and called relatives to gain information about my background, I learned a lot and yet still want to know more about my family history and background.I was able to search and find four generations in my family tree on my mother and father’s side of the family. My family consists of a mother, a father, four sisters and one brother. One pattern in particular that I notice in my family is that there is a history of preachers and pastors stemming from my father’s side of the family, but as far as I can see the ministry started with my father. My mother’s side of the family has strong roots in the church and of being saved for long periods of time.The one most characteristic that I can remember is that my parents both took us to church, bible study, Sunday school, and any service that could go on in the course of the week. My father was not only a preacher, bu t also a pastor for all my life. Now my brother is an ordained elder as well as my sister and myself. I not only have preachers in my immediate family but I have several cousins in my family that are preachers and pastors. I believe that not only were we called into the ministry; the culture that began in my father trickled down to us. It was a behavior that was taught to them and it continued in us.We were taught how to love the Lord and how to be saved. Once we were taught the way to go then my parents help us to practice this behavior on a regular basis and it became a part of our daily life, even at a young age. What was taught to us is now a way of living; it is not forced but a true way of life. Proverbs 22:6 states, â€Å"Train up a child in the way he should go: and when he is old, he will not depart from it†. I like what is said from mental health professionals, â€Å"Mental health professionals are increasingly aware that a strong spiritual base can enhance persona l resilience.The values, including sensitivity to others’ feelings, responsibility for one’s actions, personal fulfillment and satisfaction, self-discipline, forgiveness of others, healthy sexual fulfillment, and striving for a sense of purpose†(Bergin, 1991). As I think about this pattern I think about how my parents taught us the way in which we should live as well as teaching us the ways of God. Now that both parents are deceased, the understanding and truth about our beliefs and choice of a relationship with God came from the values, strengths and beliefs that have been instilled in each and every one of my sisters and brother.The African American Culture As I researched and talked to relatives concerning my background, heritage and culture, it made me want to know more about my family and where it all began. I had fun putting Together my family tree or Genogram and I see why it is important to know who we are and where we come from. I am an African American and both my parents are of African American decent. In the African American culture, many of our ancestors came to America by capture and not by choice.It is said that many African Americans were slaves and were a part of slave trade that was increased between the 15th and 19th centuries (Bennett, 2003; Van Sertima, 1976). Many African Americans were brought here to make their white or European owners money and cause them to be prosperous in areas of agriculture. There were white indentured servants, who could have worked to till the ground and make the harvest plentiful, but it wasn’t enough, so plantation owners saw it profitable to use African slaves as a solution to the problem (Zinn, 2003, p. 5). My father grew up in Alabama, which is known as the Deep South and he experienced more racial discrimination then did my mother. My father grew up poor and lack things that we as the fourth generation did not. My father always said that he would provide and make sure that we had a better life then what he had to experience. I also know that my father’s side of the family were sharecroppers and was a part of several other sharecroppers that were denied aide for their crops during times when racial discrimination was on the rise.Everything during that time was considered bad if your skin color was dark or black and if your skin color was light or white you were considered good or superior according to European Americans. Not only was black or dark skin considered inferior or bad, but European American were said to be Christian and black or dark skin was considered non-Christian. â€Å"Prejudice against skin color became the justification for brutality and hatred, and racism became important in building the nations of the Americas† (Zinn, 2003). One important aspect of the African American culture I would say would be that of the Underground Railroad.This was an important way out for many slaves in African American history. There is no way those we call African Americans could talk about slavery or being free without talking about the Underground Railroad. The Underground Railroad, lead by Harriet Tubman, was a way of freedom, or in other words a network that helped escaped slaves to make their way to the free states as well as Canada. â€Å"Between 1810 and 1860 as many as 100,000 enslaved African Americans were guided to freedom by the workers of the network, such as William Wells Brown, and Josiah Henson† (Koslow, 1999).Another great leader and activist for the African American culture would be that of Dr. Martin Luther King Jr. Dr. Martin Luther King was not only an activist and a leader for African American, but he was also a minister and pastor in the Baptist church, which is a pattern of my family background and culture. His children also walked in his footsteps, as did my sisters and brother in my father’s footsteps in the ministry. One cannot be apart of such a great movement and not be affected by i t in a positive way. I know that my father as well as Martin Luther King Jr. ould be pleased to know that the values, beliefs and morals that they instilled in us did not go in vain or return void. I believe the culture that I grew up in and around help strengthen my faith and belief I God. We not only grew up in a household with these values and morals, but in our culture there was not too many people in our family that were not saved and had a relationship with the Lord. If I went to my aunt’s house I was around salvation and a strong belief system that God is in charge of my life. If I went to my great grandmother’s house it was the same.We all shared this belief in common, a relationship with the Lord and a belief that God was the head of each of our lives. I learned at an early age to love the Lord and study to know why I believed in what I believed. I believe that on a personal level, the cultural values and systems that were instilled in me at an early age help to make me the person that I am now. I believe that being a Christian has caused me to be a lover of people, all people and regardless of their religion or background it has caused me to be open-minded.My father has always been a helper of people and he has always loved people no matter what and I truly thank God for that. I remember when I was a young child; my father would bring people to the house, all kinds of people. He did not mind and he did not care what the socio economic status of the person was, whether or not they were bi-racial, pregnant out of wedlock or an alcoholic, it did not matter to him. Now that I am writing this paper, it is giving me nothing but revelation into my true destiny in counseling. I know that my father was a counselor as well as all the other titles and positions that he held.I always knew at an early age, or during my teenage years that I was to help people. I know that because my father was the way he was it manifested into my siblings and myself. My sisters and brother and myself are natural helpers and counselors now that I think about it, wow! I never really thought about it this way until I began to write this paper. My mother would always be hesitant when my father would bring all types of people home. I remember one Christmas when my father brought home a distant relative that was an alcoholic, and he sat right beside me at the dinner table.On another occasion my father was on his way home, and he saw a couple standing at a bus stop arguing, they were young and the girl was pregnant, my father stop to talk to them and he ended up bringing them home and he ministered to them. He gave them money to get to where they were going and took them back to the bus station to get back home. My mother would always tell my father how nervous she was because he would not care who he brought into the house around us, but he was concerned about their well-being and their soul.He was a prime example of the word of God when it tells us: â€Å"And the lord said unto the servant, Go out into the highways and hedges, and compel them to come in, that my house may be filled† (Luke 14:23). I now see the same characteristics that were in my father. I believe that I am a helper by nature. I currently work as a high school teacher, and they remind me each and everyday that I am supposed to be counseling. I guess they see the natural instinct of the gift of helps in me and they utilize it everyday, and I enjoy helping and counseling them. Spirituality has historically been an important factor in the lives of Africans.There was a myth that Africans did not have God and was without a sense of spirituality, but this is not true, this myth was made up by the slave owners and those that had anything to do with bringing slaves her to America. This myth was put out to make slave owners consciences to be at ease and to allow them to feel better about what they were doing (Billingley, 1992). Other Culture Patterns There are s ome other culture patterns that I have noticed in my background in the fourth generations that I have not seen in any other generation in my family, and that is in the area of divorce.I have divorced almost 4 years now, my sister is divorced, my brother is divorced, but now remarried, and two of my first cousins are now divorced, and one of those cousins has been divorced twice. I not only see this as a pattern, but I am wondering if it is a generational curse somewhere in the family line. This is not a part of my culture in particular, the things that I have learned from my parents as far as relationships and family is concerned is not about divorce. We have an example of longevity in marriages, and they are still together until this day.As far as a counseling aspect would be, I would be able to encourage longevity as well to my clients. I believe that there are so many issues in relationships today that cause people to stray away from the family unit and break ties easier than hen my parents were alive. It was our heritage to stay together and love no matter what, that’s the heritage that I grew up around. One thing I remember was my parent being in love and if there was a problem or situation that was troubling, they didn’t let us know about it. I believe that the day and time we live in today is so unlike the day and time when my parents were married and living.I believe it is a generational aspect that allows couples to leave so easy instead of staying together, it was unheard of then and the relatives that I have that are still married now are still married from the third generation. I want to be like my parents were in my next marriage. Another pattern I see in my family is a biological one. That pattern is multiple births; this is a generational characteristic in my family. Multiple births have been seen throughout the generations in my family, stating with my great – great aunt. During a time when doctors could not detect multiple births, it was not known until a woman gave birth.During that time my great-great aunt had multiple births, some triplets and some twins, but she would lose them at the time she was due to give birth because of the technology that is here no was not here then and doctors could not prepare for the births that were to take place. I have twins throughout my family now, I have a cousin from the third generation that had two sets of twins that are two boys, and then she had a boy and girl, fraternal twins. My mother has a twin sister, who is also fraternal twins, and my mother had twins fraternally, which is my brother Jevon, and my sister Jewel.

My Stance On Gun Control - 942 Words

Gun control is one of the most highly debated topics in 2015. From the beginning of mankind, weaponry use has been a key point of survival, and has developed into recreational and political uses. So why now is it becoming such a problem? Our Second Amendment states, â€Å"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.†(â€Å"Gun Control† Opposing Viewpoints.) Clearly it has been amended without being blatantly known. For instance there are illegal weapons, and this I agree with. No one wants to fight someone with an AK-47. Really, my stance on gun control is that it should exist, but with conditions. The first condition should be a mental illness test.†¦show more content†¦If all is passed, a license is given to the carrier. I believe every purchase of a firearm should be carried out in this manner, as well as driving; but that is a different topic. As we all know, in every debate there are loopholes. One loophole is the fact that if you are a member of the U.S military, you have much more leniency in owning a weapon. I understand the fact we are supposed to be able to trust our military, but the fact is the terms and conditions of being a member are less extreme than they used to be. Now the military has a lot of policies to protect the enlisted, such as mental judgement. Lets face it, not everyone has what it takes to be in the military, but these days it seems like they will accept anyone with rock hard abs and biceps. On that note, where are the terms and conditions for ownership of a weapon for them? Do not mistake me as biased, as I watched several marines preparing for a flight and all of them brought along a duffle bag full of semi-automatics and assault weapons, yet if it was any other person attempting to bring even a handgun in their suitcase that is not even stored on the same plane, they would most likely be apprehe nded by airport police in a violent manner, including a strip search. Now why is it that 3 year veteran and Marine Sergeant 32-year-old Christopher Michael Skaggs, with a record of violence and abuse, was a â€Å"highly unlikely person to commit such an act,† and described as a

Getting an Internship in Geography

​For every college student, an internship is a very valuable method by which to obtain on-the-job experience that will not only benefit your resume and provide contacts to employers but will also help you to determine what to do after graduating. Its worth trying to obtain more than one internship during your academic career --the more experience, the better. Jobs for Geographers Now, we all know that the job listings for geographer in the classifieds are few and far between. If this were not the case, our parents and relatives would never need to ask, What are you going to do with a degree in geography, teach? (However, it is true that the U.S. Census Bureau and a few other government agencies do have positions classified as geographer!) However, the job prospects for geographers are becoming brighter with each autumnal equinox. Jobs in GIS and planning are becoming more common and geographers can easily fill these positions with experience gained in the classroom and in an internship. These two areas offer ample opportunities for internships, especially with local government agencies. While some internships are paid, the vast majority are not. A good internship will allow you to be part of the day-to-day activities of your agency - you should be part of not just the work, but also the departmental planning, discussion, and implementation. How to Get a Geography Internship While the status quo for obtaining an internship might be to go through your universitys internship office, it isnt always necessary. You can go directly to agencies youre interested in working for and inquire about internship programs. A contact through a friendly faculty member is also a good route to take. By directly volunteering your services to an agency that youre interested in working for is a quick method to begin a fun-filled educational experience outside of the classroom. Just be sure that if youre asking about an internship, that you have the appropriate skills for the job (for example, you should probably have some coursework in GIS prior to an internship in GIS.) When contacting a prospective agency about an internship, be sure to have a fresh and up-to-date resume and cover letter. Youd be amazed by the number of geography students who dont take advantage of the opportunity to intern. Youll be amazed at how much you learn from the on-the-job experience and youll be much more employable afterward. Additionally, the odds are pretty favorable that you could end up working for the agency where you had your internship. Try it. You might like it!

A Comparison Of “The Birthmark” By Nathaniel Hawthorne

A Comparison of â€Å"The Birthmark† by Nathaniel Hawthorne and â€Å"Barbie Doll† by Marge Piercy When reading a story, people do not often think about how much it might relate to another story they have read in the past. In â€Å"The Birthmark† Georgiana simply wants her unique birthmark removed from her face. Similarly, in â€Å"Barbie Doll† the unnamed young lady wants her nose and legs removed. In both of these stories the reader can see that these women are chasing society’s idea of perfection. The short story â€Å"The Birthmark† written by Nathaniel Hawthorne and the poem â€Å"Barbie Doll† written by Marge Piercy have almost the exact same theme because both of these short works of fiction are about a woman that is influenced by her peers to become†¦show more content†¦From this moment on, every acceptable quality she has will mean absolutely nothing to her. As long as she has her big nose and her two thick legs, that is all she will see herself as wholly. This leads her to thinking about permanently removing her unwanted flaws. She believes that if she removes her flaws, she will finally be accepted by society. In both stories, the reader interprets that both the woman and the young girl have specific qualities that someone in their lives has pointed out as flaws. The opinions of these certain people obviously matter to both of them, so they eventually decide that they want their flaws removed for good. When the main characters of the stories decide that they are certain that they want their flaws removed, they do not hesitate to immediately remove their imperfections. These abrupt decisions go entirely wrong for both women in the end. After all of the pressure from their peers, they remove their flaws permanently. As the unwanted mark fades from Georgiana’s face, â€Å"the parting breath of the now perfect woman passed into the atmosphere† (Hawthorne 301). Her flaw f inally leaves her face, but it unfortunately takes Georgiana’s life along with it. Similar to this situation, in â€Å"Barbie Doll† the main character decides to remove her flaws by simply cutting them off. She removes her nose and legs â€Å"and offered them up† (Piercy 771). Piercy writing that she is offering her flaws up, the author is unmistakably symbolizingShow MoreRelatedThe Puritan Effect1703 Words   |  7 PagesNathaniel Hawthorne is respected as â€Å"one of the great masters of American Fiction† (â€Å"Hawthorne, Nathaniel† 363). He is an accomplished author who wrote novels as well as children’s literature. However, Hawthorne’s strength is American short story; his â€Å"haunting† tales are undeniably responsible for establishing this genre as a â€Å"significant art form† (â€Å"Nathaniel Hawthorne† Columbia 1). He is known for his â€Å"penetrating explorations† of the conflicts within one’s conscience and the consequences thatRead MoreNathaniel Hawthorne s The Birthmark1476 Words   |  6 Pagesto the destruction of nature. In Nathaniel Hawthorne’s â€Å"The Birthmark,† it appears that Aylmer the main character wants to show the world that perfection is not beauty, and he demonstrates this with his wife Georgiana and that science should not alter the way that nature set man on this world to be. Hawthorne was a major asset to the transcendental movement, and this short story is a perfect example why. Nathaniel Hawthorne attempts to show the world the comparison between perfection and beauty mainlyRead MoreTwo Mad Scientists: a Comparison of Hawthorne’s Short Stories â€Å"the Birthmark† and â€Å"Rappaccini’s Daughter1572 Words   |  7 Pages 3 2. A Comparison of Hawthorne’s Short Stories â€Å"The Birthmark† and 3 â€Å"Rappaccini’s Daughter† 3 3.1 The Role of the Scientist 3 3.2 The Role of the Wife and daughter 4 3.3 Nature vs. Science 5 3. Conclusion 6 Works Cited 7 Honestly Declaration 8 1. Introduction In the main part of the following paper with the topic â€Å"Two Mad Scientists: A Comparison of Nathaniel Hawthorne’s Short Stories â€Å"The Birthmark† and Rappaccini’sRead MoreA Comparative Analysis of the Concepts of Science and Nature in Nathaniel Hawthornes The Birthmark and Rappaccinis Daughter1531 Words   |  6 Pages Nathaniel Hawthornes The Birthmark and Rappaccinis Daughter both address the concepts of science and nature and the conflicts that the two typically generate. The protagonists in both stories feel that it is essential for them to do something in order to improve the persons they love. Moreover, they appear to consider that they actually want to help the persons they love instead of actually helping themselves by doing so. The women in the two stories focus on being as good as they can possiblyRead MoreNathaniel Hawthorne: A Brief Biography1277 Words   |  6 Pages On July 4, 1804, an author by the name of Nathaniel Hawthorne was born (Meltzer). As Hawthorne grew, he began to develop a view of himself as â€Å"the obscurest man in American letters.† Through the use of popular themes such as isolation, guilt, and earthly imperfection, Hawthorne was able to involve much of his life and ancestral past in his work to answer his own political and religious wonders (â€Å"Nathan iel†). Hawthorne successfully â€Å"confronts reality rather than evading it† in many of his storiesRead MoreSymbolism : The Birthmark, By Nathaniel Hawthorne849 Words   |  4 Pages In the short allegory â€Å"The Birthmark†, by Nathaniel Hawthorne, a newly-wed couple becomes consumed by the existence of a small birthmark on the wife’s face. When the wife, Georgiana, allows her husband Aylmer, a scientist, to remove the birthmark, both realize that Georgiana will inevitably sacrifice her life for the sake of its removal. As the story progresses, so does the confliction of the newlyweds as they realize exactly what the birthmark symbolized to and for each other. Hawthorne’s hallmarkRead MoreSymbols, Symbolism, And Symbolism Essay960 Words   |  4 Pagessituation or word to represent something else, like an idea, in literature. There are common types of symbolism in literature. Some are Metaphors, Allegory, Colors, and objects. Metaphors are a figure of speech which makes an implicit, implied or hidden comparison between two things that are unrelated but share some common characteristics. In other words, a resemblance of two contradictory or different objects is made based on a single or some common characteristic. This is commonly used in Poetry and shortRead MoreNoble Love in The Birthmark Essay1710 Words   |  7 PagesNoble Love in  The Birthmark     Ã‚  Ã‚   Often billed as a story of an unsuccessful attempt to beat Nature at her own game, â€Å"The Birthmark† by Nathaniel Hawthorne certainly lends itself to a somewhat deeper interpretation.   Over the years many scholars have noted that the story of Aylmer and Georgiana is riddled with traditional Hawthorne themes such as the evils of selfishness and pride, coupled with an element of solitariness (Arvin xvi).   However, we are want to consider whether Aylmer’s motivesRead MoreThe Call Of Cthulhu, By Nathaniel Hawthorne1472 Words   |  6 PagesIn Nathaniel Hawthorne’s short story, â€Å"The Birth-mark,† and H.P. Lovecraft’s horror story, â€Å"The Call of Cthulhu,† there are both similarities in themes and style, however, their characterization and narration is entirely different. This lends itself to creating two different short stories, both can be classified as horror or suspenseful. Hawthorne’s story, published ear lier, shares a similar theme of humanity and union with â€Å"The Call of Cthulhu.† The documentary style of H.P. Lovecraft’s shortRead MoreElements of Comparison between Hill’s Like White Elephants and The Birthmark1268 Words   |  6 PagesBoth â€Å"Hill’s like White Elephants† by Ernst Hemingway and â€Å"The Birthmark† by Nathaniel Hawthorne have many common elements of comparison between them. The main element of the stories that will be compared is this thought of an operation. Both stories stem from these two operations and the comparisons derive from how the women react and respond to the two men in the story. Both stories are comparable by the common theme of a life changing operation, how the women first react to the operation and how

Alcohol Control Peoples Free Essays

An alcoholic beverage is a drink that contains ethanol. Alcoholic beverages are separated into three types: beers, wines, and spirits. Alcohol is a substance that a lot of people, mostly of age and people underage drink to â€Å"forget about their troubles or problems†. We will write a custom essay sample on Alcohol Control Peoples or any similar topic only for you Order Now People drink because they like it when it makes them feel on cloud 9, to feel at bliss. Alcohol is just a waste of time, money and patience. Drinking alcohol only makes you feel like you’re in another world, away from reality. But alcohol won’t help forget those things. Yes it is good sometimes to let go and relax but that doesn’t exactly mean people have to get drunk to feel relaxed. Alcohol should be banned because nothing good comes out of drinking, it causes liver damage and you say things you don’t mean. Everyone knows that alcohol messes with your mind. Nothing good comes out of it because, alcohol makes you do things without thinking. For example, drinking any type of alcohol makes people not have any recognition of what happened during that period of time when they got intoxicated. Being intoxicated makes the alcohol control peoples movements and your brain. Alcohol should be banned because when you get a hangover, it causes a severe headache. A migraine because people were over-drinking. Alcohol is practically ethanol. It’s the liquid we use to clean our cuts, for it cannot become infected. Anybody who drinks alcohol: beer, wine and/or spirits, they all contain ethanol. There is no point for people to practically drink ethanol just because they want to â€Å"relax†. It causes a severe headache, sensitivity to light, nausea, and/or vomiting. Alcohol causes liver damage. There are multiple damages that can damage a persons liver. There is a chronic disease called Cirrhosis, cirrhosis causes scaring of the liver. Alcoholic Hepatitis causes inflammation of the liver due to excessive alcohol in a body system. Alcohol damages the liver, it makes weak and poor to function. The liver is important organ in your body, it’s a fluid that breaks down fats so that smaller fatter molecules can be properly digested. Drinking alcohol will damage an important organ in peoples body. The ethanol in the alcohol damages livers, there is no point of why people want to drink something that damages what they only have. Alcohol should be banned because it changes peoples body, their mental state, and their emotional state. It’s foolish to drink this alcohol if people know it has bad side effects. Everybody always has something on their mind that they want to say out loud. A lot of people just do not have the courage to do so. A lot of people like to drown away their sorrows or problems by drinking. Thinking it’s the only way they’d be able to say the things that they have in mind, by being drunk. And when they are drunk, they are care-free, they have so much confidence to speak what they have in mind. Alcohol should be banned because a lot of people thinks it’s ok to be drunk because the wanna let go. They want to say what they feel, and they don’t want to feel what they say. People should be able to do that out of free will. They shouldn’t have to get drunk, just so they won’t feel any pain when they speak their minds. Alcohol is a bad substance, nothing good comes out of it, it causes problems in your body system, and you do and/or say stuff you don’t mean. Alcohol should be banned because it’s idiotic, how people don’t research the bad side effects from drinking alcohol. That’s why people are dying because people don’t listen. They don’t think, what would happen if they become alcoholic. Alcoholism is a serious thing and people who are addicted to alcohol should seek treatment so they can get better. Alcohol should be banned because it cause families to suffer because of their loved ones who died of alcohol poising or too much alcohol. Alcohol is dangerous, unless you take the precautions like no driving while drinking. How to cite Alcohol Control Peoples, Papers

Pile Foundations Essay Example For Students

Pile Foundations Essay CHAPTER ONE INTRODUCTION 1. OVERVIEW OF FOUNDATIONS The word foundation is derived from a latin word fondare meaning to set or ground on something solid. A foundation is that part of a structure which transmits the weight of the structure to the ground in a manner that the soil below does not fail in shear and the settlement is within the safe limits. Foundations are broadly classified into two categories: †¢ Shallow Foundation †¢ Deep Foundation A shallow foundation, according to Terzaghi is one whose width is greater than its depth ie. D/ B or = 1. The main types of shallow foundations are footings are footings and raft or mat foundation. Footings can be further subdivided as shown below: †¢ Strip Footing †¢ Spread or Isolated footing †¢ Combined Footing †¢ Strap or Cantilever Footing. The loads must be spread to the soil in a manner such that its limiting strength is not exceeded and resulting deformations are tolerable. Shallow foundations accomplish this by spreading the loads laterally, hence the term spread footing. Whereas spread footing (or simply footing) supports a single column, a mat is a special footing used to support several randomly spaced columns or to support several rows of parallel columns and may underlie a portion of or the entire building. The mat may also be supported, in turn, by piles or drilled piers. Foundations supporting machinery and such are sometimes termed bases. Machinery and the like can produce substantial load intensity over a small area, so the base is used as a load-spreading device similar to the footing. Deep foundations are analogous to spread footings but distribute the load vertically rather than horizontally. The terms drilled pier and drilled caisson are for the pile type member that is constructed by drilling a 0. 76m diameter hole in the soil, adding reinforcing as necessary, and backfilling. On the other hand, a deep foundation is that which transmits the load at considerable depth below the ground surface. The main distinction between a deep foundation and a shallow foundation is generally made according to Terzaghi’s criterion which as discussed earlier termed shallow foundation as that which its depth equals or is less than its width. A very prominent example of deep foundation that will be discussed extensively in this work is the pile foundation. 1. 2WHAT IS A PILE? A pile is a slender structural member made of steel, concrete or wood which transfer the load to a deeper soil or rock of larger bearing capacity. Piles are generally driven, drilled or jacked into the ground. Depending on the type of soil, pile material, load transmitting characteristics etc. , piles are classified accordingly as will be discussed later. Alongside piles, pile cap is a vital component of a pile foundation. Pile foundations have been used as load carrying and load transferring systems for many years. In the early days of civilization, from the communication, defense or strategic point of view villages and towns were situated near to rivers and lakes. It was therefore important to strengthen the bearing ground with some form of piling. Timber piles were driven in to the ground by hand or holes were dug and filled with sand and stones. In 1740 Christoffoer Polhem invented pile driving equipment which resembled to days pile driving mechanism. Steel piles have been used since 1800 and concrete piles since about 1900. The industrial revolution brought about important changes to pile driving system through the invention of steam and diesel driven machines. More recently, the growing need for housing and construction has forced authorities and development agencies to exploit lands with poor soil characteristics. This has led to the development and improved piles and pile driving systems. Today there are many advanced techniques of pile installation. 1. FUNCTION OF PILES Just like other types of foundations, the purpose of pile foundations is: 1. To carry vertical compression load to a solid ground. 2. To resist uplift load. 3. To resist horizontal or inclined loads A structure can be founded on piles if the soil immediately beneath its base does not have adequate bearing capacity. If the results of site investigation show that the shallow soil is unstable and weak or if the magnitude of the estimated settlement is not accepta ble a pile foundation may become considered. Considering the cost estimatation, pile foundation may pose to be cheaper compared to any other ground improvement and development costs. In the cases of heavy constructions, it is likely that the bearing capacity of the shallow soil will not be satisfactory, and the construction should be built on pile foundations. Piles can also be used in normal ground conditions to resist horizontal loads. Piles are a convenient method of foundation for works over water, such as jetties or bridge piers. 1. 4OTHER TYPES OF DEEP FOUNDATIONS 1. 4. 1Piers A pier is a vertical column of relatively larger cross-section than a pile. A pier is installed in a dry area by excavating a cylindrical hole of larger diameter to the desired depth and then backfilling it with concrete. In foundations for large buildings, piers are usually cylindrical concrete shafts, cast in prepared holes, while in bridges they take the form of caissons, which are sunk into position. Piers serve the same purpose as piles but are not installed by hammers and, if based on a stable substrate, will support a greater load than a pile. In massive construction jobs, pier shafts having widths of more than 1. m (6 feet) have been excavated to depths greater than 30 m. The lower portion of a pier may be widened to better distribute the downward pressure of a massive overlying structure. Formerly hand-dug shafts were widely used for piers where groundwater presented no serious problem, but hand excavation has been largely superseded by the use of rotary or percussion drilling. The massive augers used to drill shafts for the piers of modern skyscrap ers are mounted vertically on derricks, and the piers themselves are sufficiently long and wide to support the tremendous weight of even the tallest building. Piers for bridges are often installed by the caisson method. The caisson is a hollow boxlike structure that is sunk down through the water and then through the ground to the bearing stratum by excavating from its interior; it ultimately becomes a permanent part of the completed pier. The methods of drilled pier construction can be classified in three categories as 1. The dry method 2. The casing method 3. The slurry method ADVANTAGES AND DISADVANTAGES OF DRILLED PIER FOUNDATIONS Advantages 1. Pier of any length and size can be constructed at the site 2. Construction equipment is normally mobile and construction can proceed rapidly 3. Inspection of drilled holes is possible because of the larger diameter of the shafts 4. Very large loads can be carried by a single drilled pier foundation thus eliminating the necessity of a pile cap 5. The drilled pier is applicable to a wide variety of soil conditions 6. Changes can be made in the design criteria during the progress of a job 7. Ground vibration that is normally associated with driven piles is absent in drilled pier construction . Bearing capacity can be increased by underreaming the bottom (in non-caving materials) Disadvantages 1. Installation of drilled piers needs a careful supervision and quality control of all the Materials used in the construction 2. The method is cumbersome. It needs sufficient storage space for all the materials used in the construction 3. The advantage of increased bearing capacity due to compaction in granular soil that could be obtained in driven piles is not there in drilled pier construction 4. Construction of drilled piers at places where there is a heavy current of ground water flow due to artesian pressure is very difficult 1. 4. 3 Caissons Caissons are boxlike structure used in construction work underwater or as a foundation. It is usually rectangular or circular in plan and may be tens of metres in diameter. A box caisson, open at the top and closed at the bottom, is usually constructed on land, then launched, floated to position, and sunk onto a previously prepared foundation, leaving its upper edge above water level. It serves as a suitable shell for a pier, seawall, breakwater, jetty, or similar work, remaining permanently in place on the sea bottom. An open caisson, open at both the bottom and the top, is fitted with a cutting bottom edge, which facilitates sinking through soft material while excavation is carried out inside through a honeycomb of large pipes, or dredging wells. As excavating proceeds and the caisson sinks, additional sections are added to the shaft above. This process is continued until the caisson has sunk to the required depth. A floor, usually of concrete, is laid to provide a bottom seal. The dredging wells can then be filled with concrete to complete the structure. Pneumatic caissons are similar to open caissons except that they are provided with airtight bulkheads above the cutting edge. The space between the bulkhead and cutting edge, called the working chamber, is pressurized to the extent necessary to control the inflow of soil and water; thus the excavating can be performed by workmen operating in the working chamber at the bottom of the caisson. 1. 4. 3 Drilled Shafts The mining industry has been the primary constructor of shafts, because at many locations these are essential for access to ore, for ventilation, and for material transport. Depths of several thousand feet are common. In public-works projects, such as sewer tunnels, shafts are usually only a few hundred feet deep and because of their high cost are avoided in the design stage wherever practical. Shallower shafts find many uses, however, for penstocks and access to underground hydro plants, for dropping aqueduct tunnels beneath rivers, for missile silos, and for oil and liquefied-gas storage. Being essentially vertical tunnels, shafts involve the same problems of different types of ground and water conditions but on an aggravated scale, since vertical transport makes the operation slower, more costly, and even more congested than with horizontal tunneling. Except when there is a high horizontal geostress in rock, the loading on a shaft support is generally less than for a tunnel. Inflowing water, however, is far more dangerous during construction and generally intolerable during operation. Hence, most shafts are concrete-lined and waterproofed, and the lining installation usually follows only a short distance behind excavation. The shape is usually circular, although, before current mechanized excavation methods, mining shafts were frequently rectangular. Shafts may be sunk from the surface (or drilled in smaller sizes), or, if an existing tunnel provides access, they may be raised from below. CHAPTER TWO 2. 1NECESSITY OF PILES Some conditions where pile foundations become a necessity compared to shallow foundations in engineering practice are: 1. In the case of irregularity of a structure’s plan relative to its load distribution and outline. Non-uniform settlement will set in if the structure is constructed on a shallow foundation and therefore requires a pile foundation to reduce the differential settlement. 2. Pile foundations are used to resist horizontal forces and at the same time, support the vertical loads in earth-retaining structures that are subjected to horizontal forces due to earthquake. 3. When there is a case of high compressibility and also weakness in the strata at or just below the ground surface so that the load transmitted by the structure cannot be supported. . They are required for the transmission of structural loads through deep water to a firm stratum. 5. When the soil conditions are such that a wash out, scour or erosion of the soil may occur from underneath a shallow foundation, pile foundation is required. 6. Piles are used to transfer the load beyond the zone of possible moisture changes in the soil. This is because compressible soils such as loess have breakdown of structures accompanied by a sudden decrease in void ratio when there is an increase in water content. 7. In case of expansive soils such as black cotton soil which swell and shrink as the water content changes, pile foundation is employed so as to transfer the load below the active zone 8. In some structures which are obviously subject to uplift, Piles are used in the foundation. Examples of such structures are transmission towers, off-shore platforms etc. 9. To stiffen the soil beneath machine foundations to control both amplitudes of vibration and the natural frequency of the system. 10. When the superstructure loads are very large and shallow foundations can’t bear them CHAPTER THREE 3. 0CLASSIFICATION OF PILES Piles may be classified as long or short in accordance with the L/d ratio of the pile (where L = length, d = diameter of pile). A short pile behaves as a rigid body and rotates as a unit under Lateral loads. The load transferred to the tip of the pile bears a significant proportion of the total vertical load on the top. In the case of a long pile, the length beyond a particular depth loses its significance under lateral loads, but when subjected to vertical load, the frictional load on the sides of the pile bears a significant part to the total load. Piles may further be classified as vertical piles or inclined piles. Vertical piles are normally used to carry mainly vertical loads and very little lateral load. When piles are inclined at an angle to the vertical, they are called batter piles or raker piles. Further classifications and those which will be reviewed in this term-paper are: a) Constitutive material b) Mode of load transfer c) Method of construction d) Their use e) The displacement of soil 3. 1 MATERIAL USED Timber piles Timber piles are made of tree trunks with the branches carefully trimmed off, usually treated with a preservative, and driven with the small end as a point. Occasionally the large end is driven for special purposes as in very soft soil where the soil will flow back against the shaft and with the butt resting on a firm stratum for increased bearing. The tip may be provided with a metal driving shoe when the pile is to penetrate hard or gravelly soils; otherwise it may be cut either square or with some point. Generally there are limitations on the size of the tip and butt end as well as on the misalignment that can be tolerated. Used from earliest record time and still used for permanent works in regions where timber is plentiful. Timber is most suitable for long cohesion piling and piling beneath embankments. The timber should be in a good condition and should not have been attacked by insects. For timber piles of length less than 14 meters, the diameter of the tip should be greater than 150 mm. If the length is greater than 18 meters a tip with a diameter of 125 mm is acceptable. It is essential that the timber is driven in the right direction and should not be driven into firm ground as this can easily damage the pile. Keeping the timber below the ground water level will protect the timber against decay and putrefaction. To protect and strengthen the tip of the pile, timber piles can be provided with toe cover. Pressure creosoting is the usual method of protecting timber piles. Driving of timber piles usually results in the crushing of the fibres on the head (or brooming) which can be somewhat controlled by using a driving cap, or ring around the butt. The usual maximum design load per pile does not exceed 250 KN. Timber piles are usually less expensive in places where timber is plentiful. Concrete piles a) Precast Concrete Piles Piles in this category are formed in a central casting yard to the specified length, cured, and then shipped to the construction site. If space is available and a sufficient quantity of piles needed, a casting yard may be provided at the site to reduce transportation costs. Precast piles may be made using ordinary reinforcement or they may be prestressed. Precast piles using ordinary reinforcement are designed to resist bending stresses during pickup and transport to the site and bending moments from lateral loads and to provide sufficient resistance to vertical loads and any tension forces developed during driving. The design procedures can be found in any text on reinforced-concrete design. However temporary stresses from handling and driving (tensile) may be used that are on the order of 50 percent larger than the allowable concrete design stresses. The minimum pile reinforcement should be 1 percent. Usually of square, triangle, circle or octagonal section, they are produced in short length in one metre intervals between 3 and 13 meters. They are pre-caste so that they can be easily connected together in order to reach to the required length. This will not decrease the design load capacity. Reinforcement is necessary within the pile to help withstand both handling and driving stresses. Maximum load on a prestressed concrete pile is approximately 2000 KN and on precast piles 1000 KN. The optimum load range is 400 to 600 kN. Pre stressed concrete piles are also used and are becoming more popular than the ordinary pre cast as less reinforcement is required. b) Driven and Cast-in-Place Concrete Piles A cast-in-place pile is formed by drilling a hole in the ground and filling it with concrete. The hole may be drilled (as in caissons), or formed by driving a shell or casing into the ground. The casing may be driven using a mandrel, after which withdrawal of the mandrel empties the casing. The casing may also be driven with a driving tip on the point, providing a shell that is ready for filling with concrete immediately, or the casing may be driven open-end, the soil entrapped in the casing being jetted1 out after the driving is completed. Various methods with slightly different end results are available and patented. Note that they are basically of three types: (1) shell or cased, (2) shell-less (uncased), or (3) pedestal types. Two of the main types used in the UK are: West’s shell pile : Pre cast, reinforced concrete tubes, about 1 m long, are threaded on to a steel mandrel and driven into the ground after a concrete shoe has been placed at the front of the shells. Once the shells have been driven to specified depth the mandrel is withdrawn and reinforced concrete inserted in the core. Diameters vary from 325 to 600 mm. Franki Pile: A steel tube is erected vertically over the place where the pile is to be driven, and about a metre depth of gravel is placed at the end of the tube. A drop hammer, 1500 to 4000kg mass, compacts the aggregate into a solid plug which then penetrates the soil and takes the steel tube down with it. When the required depth has been achieved the tube is raised slightly and the aggregate broken out. Dry concrete is now added and hammered until a bulb is formed. Reinforcement is placed in position and more dry concrete is placed and rammed until the pile top comes up to ground level. Steel piles These members are usually rolled HP shapes or pipe piles. Wide-flange beams or I beams may also be used; however, the H shape is especially proportioned to withstand the hard driving stress to which the pile may be subjected. In the HP pile the flanges and web are of equal thickness; the standard W and I shapes usually have a thinner web than flange. Pipe piles are either welded or seamless steel pipes, which may be driven either open-end or closed-end. Closed-end pipe piles are usually filled with concrete after driving. Open-end piles may be filled, but this is often not necessary, because there will be a dense soil plug at some depth below the top (and visible). Here it may only be necessary to jet out some of the upper soil plug to the necessary depth for any reinforcing bars required for bending (and to pump out the water used for jetting), before filling the remainder of the pile cavity with concrete. Concrete in only this shaft depth may be necessary for dowel bars. The HP pile is a small-volume displacement pile since the cross-sectional area is not very large. A plug tends to form between the flanges at greater depths, however, so the bottom several meters may remold the soil on the order of the volume of the plug. An open-end pipe is also considered a small-volume displacement pile; however, a plug also forms inside with a depth one or more meters below the outside ground level probably from a combination of inside perimeter friction and driving vibrations. From the depth at which the plug stabilizes (not visible during driving because of the pile cap and hammer interference) to the final driving depth, the lower soil may be remolded based on the volume of the plug and not the actual area of the pipe section. Steel Iron piles are suitable for handling and driving in long lengths. Their relatively small cross-sectional area combined with their high strength makes penetration easier in firm soil. They can be easily cut off or joined by welding. If the pile is driven into a soil with low pH value, then there is a risk of corrosion, but risk of corrosion is not as great as one might think. Although tar coating or cathodic protection can be employed in permanent works. It is common to allow for an amount of corrosion in design by simply over dimensioning the cross-sectional area of the steel pile. In this way the corrosion process can be prolonged up to 50 years. Normally the speed of corrosion is 0. 2-0. 5 mm/year and, in design, this value can be taken as 1mm/year Composite piles A composite pile comprises the combination of different materials in the same of pile. As indicated earlier, part of a timber pile which is installed above ground water could be vulnerable to insect attack and decay. To avoid this, concrete or steel pile is used above the ground water level, whilst wood pile is installed under the ground water level. This type is rarely used used in practice due to the difficulty encountered in the provision of a proper joint. . 2 Classification of pile with respect to load transmission and functional behavior a) End bearing piles (point bearing piles) b) Friction piles (floating piles) c) Combination of friction and end-bearing piles End bearing piles (Point bearing piles) These piles transfer their load through their bottom tip on to a firm stratum located at a considerable depth below the base of the structure and they derive mo st of their carrying capacity from the penetration resistance of the soil at the toe of the pile. The pile behaves as an ordinary column and should be designed as such. artificial intelligence EssayOnce the unit skin friction has been estimated, the shaft resistance is determined from equation For cohesive soils, the ultimate load can be determined by adding the point resistance and the shaft resistance equation (5. 1) Thus; As the clay gets remoulded when the pile is driven, this factor must be taken into account when estimating the load carrying capacity. The remoulded strength is always less than the undisturbed strength, but because of thixotropy, the strength depends upon the consolidation characteristics of the soil and the rate of dissipation of excess water pressure. When using equation , the value of c and c should be judiciously evaluated. 5. 2 NEGATIVE SKIN FRICTION AND ITS EFFECT ON PILES When the fill starts consolidating under its own overburden pressure, it develops a drag on the surface of the pile. This drag on the surface of the pile is called negative friction. Negative friction may develop if the fill material is loose cohesionless soil. Negative friction can also occur when fill is placed over peat or a soft clay stratum. The superimposed loading on such compressible stratum causes heavy settlement of the fill with consequent drag on piles. Negative friction may develop by lowering the ground water which increases the effective stress causing consolidation of the soil with resultant settlement and friction forces being developed on the pile. Negative friction must be allowed when considering the factor of safety on the ultimate carrying capacity of a pile. The factor of safety, Fs, where negative friction is likely to occur may be written as Computation of Negative Friction on a Single Pile The magnitude of negative friction Fn for a single pile in a fill may be taken as (a) For cohesive soils . b) For cohesionless soils Where Ln = length of piles in the compressible material, s = shear strength of cohesive soils in the fill, P = perimeter of pile, K = earth pressure coefficient normally lies between the active and the passive earth pressure coefficients, ? = angle of wall friction which may vary from ? /2 to ?. Negative Friction on Pile Groups When a group of pils passes through a compressible fill, the negative fri ction, Fn , on the group may be found by any of the following methods (a) †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. i (b) †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ii where n = number of piles in the group, = unit weight of soil within the pile group to a depth Ln, P = perimeter of pile group, Ag sectional area of pile group within the perimeter Pg , s = shear strength of soil along the perimeter of the group. Equation i gives the negative friction forces of the group as equal to the sum of the friction forces of all the single piles. Eq ii assumes the possibility of block shear failure along the perimeter of the group which includes the volume of the soil yLnA enclosed in the group. The maximum value obtained from Eqs i or ii should be used in the design. OTHER METHODS OF DETERMINING ULTIMATE LOAD BEARING CAPACITY OF A SINGLE VERTICAL PILE The ultimate bearing capacity, Qu, of a single vertical pile may also be determined by any of the following methods: 1. By the use of SPT and CPT values. 2. By field load tests. 3. By dynamic method. 5. 3DYNAMIC FORMULAE The load-carrying capacity of a driven pile can be estimated from the resistance against penetration developed during the driving operation. The methods give fairly good results only in the case of free-draining sands and hard clays in which high pore pressure does not develop during the driving of the piles. In saturated fine-grained soils, high pore water pressure develops during the driving operation and the strength of the soil is considerably changed and the methods do not give reliable results. The methods cannot be used for submerged, uniform fine sands which may become loose enough to become quick temporarily and show a much less resistance. The dynamic formulae are based on the assumption that the kinetic energy delivered by the hammer during driving operation is equal to the work done on the pile. Thus; Where W – weight of the hammer h – Height of the ram drop – Efficiency of the pile hammer R – Pile resistance taken to equal Qu S – Pile penetration per blow In equation above, no allowance has been made for the loss of energy during driving operation, loss caused by elastic contraction of the pile, soil, pile cap, cushion and due to the inertia of the pile. Some energy is also lost due to generation of heat. Various formulae have been proposed, which basically differ only in the methods for accounting of the energy losses, as described below: 5. 3. 1Engineering News Record Formulae According to Engineering News Record (ENR) Formulae (1888), the ultimate load is given by Where S – penetration of the pile per hammer blow C – constant ( for drop hammer, C = 2. 54cm and for steam hammer, C = 0. 245) In equation (5. 17), the product can be replaced by the rated energy of hammer (En) in KN-cm. Thus, The efficiency ? h of the drop hammer is generally 0. 7 and 0. 9, and that for a single-acting and a double-acting hammer is between 0. 75 and 0. 85. For diesel hammer, it usually lies between 0. 80 and 0. 90. A factor of safety of 6 is usually recommended. However, the pile load tests reveal that the actual factor varies between 23 and 30. The formula is, therefore, not dependable. Modified formula The Engineering News Record Formulae has been modified recently. In the modified formula, the energy losses in the hammer system and that due to impact are considered. According to this formula; Where P – weight of pile e Coefficient of restitution ?h -hammer efficiency The hammer efficiency (? h) depends upon various factors, such as pile driving equipment, driving procedure, type of pile and the ground conditions. For drop hammers, it is usually taken between 0. 75 and 1. 0; for single acting hammers between 0. 75 and 0. 85; for double-acting or differential hammer, ? 0. 85 and for diesel hammer, ? = 0. 85 to 1. 0. The representative values of the coefficient of restitution (e) are as follows: Broomed timber pile=0. 0 Good timber pile =0. 25 Driving cap with timber dolly on steel pile =0. 3 Driving cap with plastic dolly on steel pile=0. 5 Helmet with composite plastic dolly and packing on R. C. C. pile = 0. 4 5. 3. 2. Hiley Formula Hiley (1925, 1930) gave a formula which takes into account various losses. Where ? h efficiency of hammer blow H height of free fall of the room or hammer S final set or penetration per blow C Sum of temporary elastic composition of the pile, dolly, packings and ground (= C1 + C2 + C3), C1 = temporary compression of dolly and packings (= 1. 77 R/A), when the driving is without dolly, = 9. 05 R/A when the driving is with short dolly), C2 = temporary compression of pile (= 0. 657 RD/A), C3 = temporary compression of ground (= 3. 55 R/A). D Length of the pile A Cross-sectional area of pile P Pile resistance The efficiency of the hammer blow (? h) depends upon the weight of hammer (w), weight of pile, anvil and helmet follower (P) and the coefficient of restitution (e). ) For , b) For , The coefficient of restitution (e) varies from zero for a deteriorated condition of the head of pile to 0. 5 for a steel ram of double acting hammer striking on steel anvil and driving a reinforced concrete pile. For a C. I. ram of a single – acting or drop hammer striking on the head of R. C. C. pile, e = 0. 4 and that striking on a well-conditioned driving cap and helmet with h ard wood on R. C. C. pile, e = 0. 25 (IS:2911 – 1979). 5. 3. 3Danish Formula According to Danish Formula (1929) Where In which So=elastic compression of pile D=Length of pile A=Cross-sectional area E=Modules of elasticity of pile material The allowable load is found by taking of factor of safety of 3 or 4. Equation (5. 24) can also be used to determine the final set (S) per blow Taking . Where 5. 4Comments On The Use Of Dynamic Formulae: 1. Detailed investigations carried out by Vesic (1967) on deep foundations in granular soils indicate that the Engineering News Record Formula applicable to drop hammers. In order to obtain better agreement between the one computed and observed loads, Vesic suggests the following values for the coefficient C. For steel pipe piles, C = 1 cm. For precast concrete piles C = 1. 5 cm. 2. The tests carried out by Vesic in granular soils indicate that Hileys formula does not give consistent results. The values computed from are sometimes higher and sometimes lower than the observed values. 3. Dynamic formulae in general have limited value in pile foundation work mainly because the dynamic resistance of soil does not represent the static resistance, and because often the results obtained from the use of dynamic equations are of questionable dependability. 4. Dynamic formulae could be used with more confidence in freely draining materials such as coarse sand. If the pile is driven to saturated loose fine sand and silt, there is every possibility of development of liquefaction which reduces the bearing capacity of the pile. 5. Dynamic formulae are not recommended for computing allowable loads of piles driven into cohesive soils. In cohesive soils, the resistance to driving increases through the sudden increase in stress in pore water and decreases because of the decreased value of the internal friction between soil and pile because of pore water. These two oppositely directed forces do not lend themselves to analytical treatment and as such the dynamic penetration resistance to pile driving has no relationship to static bearing capacity. There is another effect of pile driving in cohesive soils. During driving the soil becomes remolded and the shear strength of the soil is reduced considerably. Though there will be a regaining of shear strength after a lapse of some days after the driving operation, this will not be reflected in the resistance value obtained from the dynamic formulae. 5. IN-SITU PENETRATION TEST FOR PILE CAPACITY 5. 5. Standard penetration Test. The load carrying capacity of a pile can be estimated from the standard penetration test value (N). i. For driven piles in sand, the unit tip resistance (qp) is related to the uncorrected blow count (N) near the pile point (Meyerhof 1976). Q p = 40N (D/B) ; 400N Where qp = point resistance (Kn/m2), D = Length of pile, B = width (diameter) of pile. The value of qp is u sually limited to 400N. The average unit frictional resistance (fs) is related to the average value of the blow count (N). For high displacement piles, fs = 2. 0N kNm2 For low displacement piles, fs = 1. N kNm2 Where N is average of uncorrected N-value along the length of the piles. ii. For bored piles in sand, qp = 14 N (Db/B) kN/m2 Where Db = actual penetration into the granular soil. For bored piles in sand, the unit frictional resistance (fs) is given by fs = 0. 67 N kNm2 5. 5. 2Dutch cone test: Meyerhof (1965) relates the unit point resistance (qp) and unit skin traction (fs) of driven piles to the cone point resistance. (qc) Point resistance Unit skin friction (a) fs (dense sand) = qc / 200 (b) fs (loose sand) = qc / 400 (c) fc (silt) = qc / 150 . 5. 3 PILE LOAD TEST The load test may be carried out either on a driven pile or a cast-in-situ pile. Load tests may be made either on a single pile or a group of piles. Load tests on a pile group are very costly and may be undertake n only in very important projects. Pile load tests on a single pile or a group of piles are conducted for the determination of 1. Vertical load bearing capacity, 2. Uplift load capacity, 3. Lateral load capacity. Generally load tests are made to determine the bearing capacity and to establish the load settlement relationship under a compressive load. The other two types of tests may be carried out only when piles are required to resist large uplift or lateral forces. Usually pile foundations are designed with an estimated capacity which is determined from a thorough study of the site conditions. At the beginning of construction, load tests are made for the purpose of verifying the adequacy of the design capacity. If the test results show an inadequate factor of safety or excessive settlement, the design must be revised before construction is under way. Load tests may be carried out either on 1. A working pile or 2. A test pile. A working pile is a pile driven or cast-in-situ along with the other piles to carry the loads from the superstructure. The maximum test load on such piles should not exceed one and a half times the design load. A test pile is a pile which does not carry the loads coming from the structure. The maximum load that can be put on such piles may be about 2J/2 times the design load or the load imposed must be such as to give a total settlement not less than one-tenth the pile diameter. Method of Carrying Out Vertical Pile Load Test A vertical pile load test assembly is shown in Fig. 15. 19(a). It consists of 1. An arrangement to take the reaction of the load applied on the pile head, 2. A hydraulic jack of sufficient capacity to apply load on the pile head, and 3. A set of three dial gauges to measure settlement of the pile head. Load Application A load test may be of two types: 1. Continuous load test. 2. Cyclic load test. In the case of a continuous load test, continuous increments of load are applied to the pile head. Settlement of the pile head is recorded at each load level. In the case of the cyclic load test, the load is raised to a particular level, then reduced to zero, again raised to a higher level and reduced to zero. Settlements are recorded at each increment or decrement of load. Cyclic load tests help to separate frictional load from point load. The total elastic recovery or settlement Se, is due to 1. The total plastic recovery of the pile material, 2. Elastic recovery of the soil at the tip of the pile, Sg The total settlement S due to any load can be separated into elastic and plastic settlements by carrying out cyclic load tests as shown in Fig. 15. 19(b). A pile loaded to Ql gives a total settlement Sr When this load is reduced to zero, there is an elastic recovery which is equal to Sel. This elastic recovery is due to the elastic compression of the pile material and the soil. The net settlement or plastic compression is S r The pile is loaded again from zero to the next higher load Q2 and reduced to zero thereafter. The corresponding settlements may be found as before. The method of loading and unloading may be repeated as before. Allowable Load from Single Pile Load Test Data There are many methods by which allowable loads on a single pile may be etermined by making use of load test data. If the ultimate load can be determined from load-settlement curves, allowable loads are found by dividing the ultimate load by a suitable factor of safety which varies from 2 to 3. A factor of safety of 2. 5 is normally recommended. A few of the methods that are useful for the determination of ultimate or allowable loads on a single pile are given below: 1. The ultimate load, Qu, can be determined as the abscissa of the point where the curved part of the load-settlement curve changes to a falling straight line. . Qu is the abscissa of the point of intersection of the initial and final tangents of the load-settlement curve 3. The allowable load Q is 50 percent of the ultimate load at which the total settlement amounts to one-tenth of the diameter of the pile for uniform diameter piles. the manner in which the foundation piles are to be installed. The test piles should be atleast 3 B or 2. 5 m clear from the anchor piles. 4. The allowable load Qa is sometimes taken as equal to two-thirds of the load which causes a total settlement of 12 mm. 5. The allowable load Qa is sometimes taken as equal to two-thirds of the load which causes a net (plastic) settlement of 6 mm. DETERMINATION OF ULTIMATE LOAD FROM LOAD SETTLEMENT CURVES If pile groups are loaded to failure, the ultimate load of the group, Q u, may be found by any one of the first two methods mentioned above for single piles. However, if the groups are subjected to only one and a half-times the design load of the group, the allowable load on the group cannot be found on the basis of 12 or 6 mm settlement criteria applicable to single piles. In the case of a group with piles spaced at less than 6 to 8 times the pile diameter, the stress interaction of the adjacent piles affects the settlement considerably. The settlement criteria applicable to pile groups should be the same as that applicable to shallow foundations at design loads. OTHER TYPES OF PILE LOAD TESTS 1. Constant rate of penetration test. In a constant-rate of penetration tests, the load on the pile is continuously increased to maintain a constant rate of penetration (from 0. 25 to 5 mm per minutes). The force reqiur3ed to achieve that rate of penetration is recorded, and a load settlement curve is drawn. The ultimate curve can be determined from the curve. 1) Routine Load test. This test is carried out on a working pile with a view to determine the settlement corresponding to the allowable load. As the working pile would ultimately form a part of the foundation, the maximum load is limited to one and half times the safe load or upto the load which gives a total settlement of 12 mm. 2) Cyclic Load test. The load is carried out for separation of skin friction and point resistance of a pile. In the test, an incremental load is repeatedly applied and removed. 3) Lateral Load test. The test is conducted to determine the safe lateral load on a pile. A hydraulic jack is generally introduced between two pile to apply a lateral load. The reaction may also be suitably obtained from some other support. The test may also be carried out by applying a lateral pull by a suitable set-up. 4) Pull out test. The test is carried out to determine the safe tension of a pile. In the set-up, the hydraulic jack rests against a frame attached to the top of the test pile such that the pile gets pulled up. CHAPTER SIX GROUP ACTION OF PILES. A pile is not used singularly beneath a column or a wall, because it is extremely difficult to drive the pile absolutely vertical and to place the foundation exactly over its centre over its centre line. If eccentric loading result, the connection between the pile and the column may break or the pile may fail structurally because of bending stresses. In actual practice, structural load are supported by several piles acting as a group. For columns, a minimum of three piles in a triangular pattern are used. For walls, piles are installed in a staggered arrangement on both sides of its center line. The loads are usually transferred to the pile group through a reinforced concrete slab, structurally tied to the pile tops such as that the piles act as one unit. The slab is known as a pile cap. The load acts on the pile cap which distributes the load tom the piles. The load carrying capacity of a pile group is not necessarily equal to the sum of the capacity of the individual piles. Estimation of the load-carrying capacity of a pile group is a complicated problem. When the piles are spaced a sufficient distance apart, the group capacity may approach the sum of the individual capacities. On the other hand, if the piles are closely spaced, the stresses transmitted by the piles to the soil may overlap, and this may reduce the load-carrying capacity is limited by the group action. The efficiency () of a group of pile is defined as the ratio of the ultimate load of the group to the sum of individual ultimate loads. Or Where Qg(u) = ultimate load of the group, Q(u) = ultimate load of the individual pile, N = Number of piles in the group. Thus the group efficiency is equal to the ratio of the average load per pile in the group at which the failure occurs to the ultimate load of a comparable single pile. The group efficiency depends upon the spacing of the piles. Ideally, the spacing should be sure that the efficiency is 100%. Generally, the centre to centre spacing is kept between 2. 5 B and 3. 5 B, where B is the diameter of the pile. The methods for the determi