How one design flaw almost toppled a skyscraper - Alex Gendler

翻译人员: A G 校对人员: Helen Chang

In 1978, Diane Hartley was writing her undergraduate architecture thesis

1978年，当戴安娜·哈特利 正在编写她的本科建筑论文时，

when she made a shocking discovery.

她有了一个惊人的发现。

Her paper focused on the Citicorp Center, a skyscraper in midtown Manhattan.

论文的重心在花旗中心， 曼哈顿中城的摩天大楼。

And after weeks poring over the building’s plans,

在对建筑计划经过几周的研究后，

she’d stumbled on a potentially deadly mistake.

她发现一个潜在的致命错误，

An oversight that threatened to topple the 59-story tower

可能会让这59层大楼坍塌，

into one of New York City’s most densely populated districts.

位于纽约市人口最密集的地区之一。

When it was built two years earlier,

当两年前刚建成时，

Citicorp Center was one of the world's tallest buildings.

花旗中心大厦 是世界上最高的建筑之一。

Its sloped roof was unique in the city skyline,

倾斜式屋顶在城市中十分显眼，

but its more distinctive feature lay at the base.

但更独特的是它的根基。

Since the construction site was already occupied by St. Peter's Lutheran Church,

由于圣彼得路德教会 已经占领了建造区域的一角，

the new skyscraper had to be built on columns supporting it, like stilts.

这座新大楼需要像踩高跷一样 用柱子在下面支撑着。

Using stilts on a building’s corners wasn’t unheard of,

用柱子支撑建筑物的角落 这种方法不是前所未闻，

but because the church stood at the corner of the block,

但因为教会矗立在建筑区域的角落，

these stilts had to be placed at the center of each side.

这些柱子需要放置在每边的中心。

While this novel design worried some of the building's backers,

为了消除投资者们的不安，

chief structural engineer William LeMessurier

首席结构工程师威廉·勒梅苏里尔

took numerous precautions to ensure the building’s stability.

采取了许多预防措施 以确保建筑的稳定性。

The outside would consist of v-shaped chevrons,

第一，建造v形状的外层，

forming a strong exoskeleton to support the skyscraper.

以构成强大的外骨骼结构 用于支撑大楼。

This external structure also made the building much lighter,

让整体更加光亮的同时，

meaning there’d be less weight to support overall.

也减少了需要支撑的重量。

This design did leave the building vulnerable to strong winds.

但这样的设计会让楼层 在起大风时非常脆弱。

But LeMessurier had another state-of-the-art solution—

这让勒梅苏里尔想出 一个超前的解决方案——

a tuned mass damper.

一个调谐质量阻尼器。

This 400-ton counterweight was controlled by computerized sensors

这个400吨的配重 由电脑传感器来控制，

designed to counteract any swaying.

可以抵消任何摆动。

With these structures in place,

如果设置到位，

calculations showed that each side of the building could withstand powerful winds.

计算显示每边可以均匀地承受强风。

And with all safety issues resolved, the building opened for business in 1977.

做完所有的安全措施后， 大厦在1977年正式对外开放。

But when Hartley was studying the tower a year later, she noticed something odd.

但当一年后哈特利研究时， 她注意到了一些奇怪的事情。

It was true that each face of the building could endure powerful winds.

确实，建筑的每个面都可以承受强风。

And since a building’s broad sides catch the most wind,

由于一个建筑的宽边能承受最多的风，

these would typically be the strongest winds a building encounters.

因此这通常也是建筑物 会遇到的最强的风。

However, the towers unique base meant that winds

然而，这座塔独特的地基意味着

blowing on the building’s corners were actually the bigger threat.

吹在角落的风其实更危险。

And since traditional designs didn't warrant safety calculations

由于传统设计没有 保证角风的安全计算，

for corner winds,

it seemed to Hartley that the threat had gone unaccounted for.

对哈特利来说，这是个 没人注意到的危险要素。

When Hartley contacted LeMessurier’s firm about the issue

之后哈特利联络 勒梅苏里尔的公司说明情况，

they assured her the building was strong enough to handle these winds.

他们保证了建筑强度 已经足够应付强风。

But checking the plans again, LeMessurier noticed an alarming detail.

但是当勒梅苏里尔再一次查翻方案后

发现一个细节警讯，

A change approved without his knowledge

那是他未被知会却被许可的细小改动：

had replaced the exoskeleton’s welded joints

外骨骼的焊接接头已经被 更便宜更弱的螺栓连接所替换。

with cheaper and weaker bolted joints.

This alone wasn’t enough to topple the tower thanks to the mass damper.

由于质量阻尼器，仅凭这一点 还不足以使高楼倒下。

But if a storm knocked out the building's power,

但如果电力因为风暴突然关闭，

it would deactivate the counterweight’s sensors,

平衡重的感应器也会随着关闭，

leaving the building vulnerable to winds of just 112 kilometers per hour.

使建筑容易受到风的影响， 即使每小时仅仅112公里的风。

Given available weather data,

鉴于可靠的天气数据，

a storm this strong had a one-in-sixteen chance

这么强的风暴每年有16分之一的机会

of hitting New York City every single year.

来到纽约市。

LeMessurier never told Hartley what she’d uncovered.

勒梅苏里尔没有告诉哈特利 她发现了什么。

In fact, everything he did next was top secret.

实际上，他接下来所做的一切 都是最高机密。

After filling in the architects and executives at Citicorp,

在告诉花旗公司的建筑师和高管后，

LeMessurier’s team worked with city officials to craft a confidential plan.

勒梅苏里尔的团队与市政府官员合作 制定了一项保密计划。

Without warning the residents,

在未警示居民的情况下，

construction crews began a string of night-time shifts

施工人员开始了一系列夜班

to reinforce the bolted joints.

以加强螺栓连接。

This delicate work began in mid-August 1978,

这精巧的工程于1978年8月中旬开始，

and was only halfway complete when Hurricane Ella

但在9月飓风艾拉侵袭城市时 只完成了一半。

approached the city in September.

City officials and Citicorp executives planned an emergency evacuation

市政府官员与花旗公司高管 只能计划紧急疏散

for a 10-block radius,

附近十个街道的范围，

but at the last minute, the hurricane veered out to sea.

所幸在最后一刻，飓风转向了大海。

These secret evacuation plans were never used,

这些秘密疏散计划从未被使用过,

and the reinforcements were completed just a month later.

加强螺栓的工程在一个月后完工。

Typically, it would’ve been impossible for this covert construction to go unnoticed.

通常这种隐蔽的施工不可能会被忽视。

But the press was occupied with a newspaper strike

但是新闻报道被报纸罢工占去了，

spanning the length of the reinforcement project.

长达一整个加固工程期。

In fact, the public didn't learn how close they'd come to disaster until 1995,

事实上，公众直到1995年 才知道他们离灾难有多近，

when a New Yorker article revealed the story to the city, and to Diane Hartley.

到那时《纽约客》的一篇文章

才向纽约市民和黛安·哈特利 揭露此事。

Like LeMessurier, the article failed to give credit where it was due,

像勒梅苏里尔一样，这篇文章 没有归功给正确的人，

but at least Hartley knew that her homework had saved lives.

但至少哈特利知道她的作业救了人。