首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The Fall of WorId Trade Centre I. Flashback of the disaster A. The twin towers of the World Trade Center collapsed B. A rela
The Fall of WorId Trade Centre I. Flashback of the disaster A. The twin towers of the World Trade Center collapsed B. A rela
admin
2022-01-23
64
问题
The Fall of WorId Trade Centre
I. Flashback of the disaster
A. The twin towers of the World Trade Center collapsed
B. A relative success in terms of【T1】___________
- the buildings performed "magnificently"
- the towers stayed standing for about【T2】______each
II. An extraordinary design
A.【T3】______skyscrapers
-【T4】_________throughout a building
- diagonal beams as their means of support
B. twin towers
- designed and built with special attention to【T5】________
-【T6】______hurricane-force winds of up to 200 mph
- sway up to several feet【T7】___________
- the secret of its build-up:【T8】__________
- supporting steel column
- majority of the beams framed the outside walls—a solid "【T9】______" design
- smaller group of steel beams shot【T10】____of the buildings and bore【T11】________of supporting the towers
III. The fundamental cause of its collapse:【T12】______
A. the high temperature failed【T13】________and weakened the insulation around the steel
B. the heat【T14】_____________
C. top-floor fell and hence the demolition IV. Collapse: a controlled demolition, like a【T15】____________
【T12】
The Fall of World Trade Centre
Well, my topic today is Architecture, and to be specific, what I am going to talk about is World Trade Centre — the skyscrapers.
After watching the twin towers of the World Trade Center collapse, twice reducing 110 stories to five in less than a minute, it’s hard to see how the buildings could have ever been considered safe. It’s even harder to see how engineers can look at the events of September 11, 2001, as a relative success in terms of architectural strength. Consider this: the rubble at the site weighed a million tons. The site spanned a vast 16 acres. The nonstop cleanup, conducted day and night, still took the better part of a year. Even if the greatest loss — so many human lives — is excluded, there’s no arguing: this was, in all senses, an enormous disaster.
And yet, for all the destruction — and for all the disbelief. Americans felt as they watched the towers collapse — engineers unanimously say that the buildings performed "magnificently" after terrorists crashed a plane into the side of each. Because the towers stayed standing for about an hour each, they gave rescue workers enough time to get tens of thousands of people out. The towers owed their resilience largely to their architect, Minoru Yamasaki and structural engineer Leslie Robertson. The men’s original design enabled the buildings to withstand the impact of the planes, only after jet-fuel fires weakened their steel beams.
Constructed with cheaper methods, many other buildings would have collapsed immediately. Today’s most common skyscraper design places vertical support beams throughout a building. Others have diagonal beams as their means of support. But the World Trade Center was built before those were the standards. Raised in the 1960’s, the glass-and-steel towers were designed and built with innovation and special attention to safety and stability because of their extreme height. Engineers wanted to make sure the towers could withstand hurricane-force winds of up to 200 mph — on an especially windy day, the towers could sway up to several feet in either direction. With memories of a 1945 plane crash into the Empire State Building lurking in their minds, engineers and architects also designed the towers to withstand the force of a Boeing 707.
There are several reasons to make the tower magnificent. Firstly, the engineers agreed that the secret to ensuring the buildings would stand tall under extreme circumstances rested in their supporting steel columns, which were set up differently from most skyscrapers’. Secondly, the majority of the beams framed the outside walls of the towers: 61 beams per 211-foot side provided maximum reinforcement. Engineers often refer to this as a solid "steel tube" design, and rightly so compared to most buildings, which may have vertical support columns spaced as far as 20 feet apart. Thirdly, the outer columns helped the buildings withstand a huge wind load, but another smaller group of steel beams shot through the centers of the buildings and bore the main load of supporting the towers. This "core", which housed elevator shafts and stairwells, was connected to the outer steel columns by still more steel running through each concrete floor. The "double support" may have been what ultimately kept the buildings standing for so long.
What actually caused the twin towers to fall? All the same, no amount of reinforcement could have prevented the towers’ eventual collapse. Immediately after September 11, most engineers thought the fires, and not the planes’ impacts, were to blame. That theory has generally held up. A federal investigation was inconclusive, but it did conform with engineers’ suspicions. The steel columns didn’t actually melt. But as the fires inside the buildings consumed more and more jet fuel — about 24,000 gallons of it — they overwhelmed the buildings’ sprinkler systems, started to weaken the concrete insulation around the steel, and then deliberated the steel itself. Most of the fluffy fireproofing material on the towers’ steel columns was blasted off by the plane crashes. With flames reaching temperatures of 1,500 degrees Fahrenheit and higher, the steel columns started to warp, and the top floors buckled. From then on, the towers had no more chance of standing than a building targeted for demolition. Their collapse was the first known instance of steel buildings collapsing because of fire alone.
In fact, the collapse played out just like a controlled demolition. To destroy a building, experts usually place explosives not just on the lowest three floors, but also on higher floors. With the top floors exploding, demolition experts can create what they call a "pancake effect", which you might realize is the same as a downward domino-effect. Unlike dominos, of course, the towers fell straight down rather than sideways. But their downfall was caused by the same forces that knock a line of dominos on their faces: Floors on the top gave in, crashing through the floors below them. As each concrete floor fell, it added force to the collapse — making it harder for each floor to hold up against the increasing pressure. Once the top floors gave way, the rest of the catastrophe was inevitable.
To be exact, many lives lost, but many saved. If the towers were never going to stay standing, why all the extra support? Was it futile after all? Suppose for a minute that the towers hadn’t been built with all that reinforcement — that they’d collapsed a few minutes after being struck. The rubble at the side still would weigh a million tons. The site still would have taken as long. But how many more people would have died? It’s a figure no one wants to calculate. Thankfully, because a team of engineers and architects made the Trade Center as safe as it could possibly be.
To sum up, I first recalled the disastrous episode of the fall of the World Trade Centre, then I explained how extraordinary the design is. After that, I summarized the reasons of its catastrophic collapse. That’s it for today.
选项
答案
fires
解析
归总题。讲座里提到: Immediately after September , most engineers thought the fires, and not the planes’ impacts, were to blame.从这句话可以归纳出真正的罪魁祸首是火。
转载请注明原文地址:https://kaotiyun.com/show/B7IK777K
0
专业英语八级
相关试题推荐
(1)Ifyouwanttoseewhatittakestosetupanentirelynewfinancialcenter(andwhatisbestavoided),headforDubai.This
Duringtheearlyyearsofthiscentury,wheatwasseenastheverylifebloodofWesternCanadaPeopleoncitystreetswatchedt
HowtoConquerPublicSpeakingFearI.IntroductionA.Publicspeaking—acommonsourceofstressforeveryoneB.Thetruthabou
A、Hisreputationasacook.B、Hisresearchonlanguagelearning.C、HisfluencyandproficiencyinSpanish.D、Hisregularstudyo
DaydreamingI.DaydreamingcanbeharmfulbecauseitwasconsideredasA.awasteof【T1】______【T1】______B.a【T2】______ofne
A、Shestartedsingingoperaataprettyyoungage.B、SheplayedmusicwithfriendsinDetroit.C、Besidesmusic,shehadnoextra
A、Freeticket.B、Freephonecall.C、Cashreward.D、Seatreservation.D本题考查对于主动转乘下一航班的旅客的补偿。根据录音,这样的旅客有可能得到cashbribe或afreetrip
A、75%ofthem.B、40%ofthem.C、35%ofthem.D、17.5%ofthem.A本题考查今年有多少美国人打算找新工作。访谈中,女士提到一个调查显示今年约有75%的美国人打算找新工作,因此选A。B中的40%是今年
A、Itwasunheardof.B、Itwasonasmallscale.C、Itwasinsignificant.D、Itoccurredelsewhere.D细节理解题。本题考查受采访者对阿富汗大选存在欺诈现象的看法,
PASSAGEONEWhydidn’ttheWiesenthalCenterpurchasetheGemlichletterin1988?
随机试题
糖尿病酮症酸中毒发病的根本原因是
女性,65岁,间歇性胸闷、胸痛8年,心悸、气短2个月入院,测血压150/90mmHg。口服地高辛0.25mg和呋塞米20mg,每天1次。5d后复查心电图示,心率90次/分,律不整,房颤律,Ⅱ、Ⅲ、avF导联有病理Q波,并有频发的室性期前收缩。针对病因和
A.阳和汤B.桃红四物汤C.四妙勇安汤D.八珍汤合左归丸E.十全大补汤治疗动脉硬化性闭塞症脾肾阳虚证应首选()
按照《献血法》的规定,表述错误的是()
个人征信系统的积极作用体现在()。
下列表明存货可变现净值为零的有()。
咨询过程中最核心、最重要的实质阶段是()阶段。
为纪念五四运动100周年,中共中央政治局就五四运动的历史意义和时代价值举行了集体学习。下列选项中关于五四运动及五四精神的说法错误的是:
有其父必有其子。
在Catalyst3548上建立ID号为120,名为phy120的VLAN,并删除ID号为100,名为phy100的VLAN,正确的配置命令是()。
最新回复
(
0
)