受台风“烟花”影响,上海维持大风大雨的天气,雨势时强时弱。“烟花”来势汹汹,摩天大楼如何稳如泰山?在中国第一高楼之称的上海中心大厦上,堪称“镇楼神器”的阻尼器开始出现摆动,给摩天大楼进行减振。据说上海中心大厦顶部晃动幅度是按照刮台风时最大可达1.4米设计,本身在抗摇晃方面表现优秀,它是如何实现的呢?
Wind is one of the most important factors that architects and engineers must consider when designing tall buildings.
While skyscrapers might appear to be highly-strengthened, immovable structures, all tall buildings are in fact designed with a degree of flexibility in mind.
This is principally due to the impact that wind forces (known as "wind loads") have on a building as it becomes taller.
Whilst you might be experiencing a pleasant breeze at street-level, the force of the wind generally grows much stronger the higher up you travel.
While the steel and concrete used in a skyscraper's superstructure is designed to bend and flex to absorb the impact that these wind loads have, the degree to which a structure is able to move can have a significant impact on the comfort of those inside the building.
When buildings first began to grow tall in the 1890s and 1900s, height limits were imposed - such as those introduced in Chicago - to prevent their masses from blocking sunlight.
In New York City, ordinances were passed that allowed tall buildings to develop on the basis that they were set-back after reaching a certain height.
This allowed sunlight to reach street-level whilst breaking-up the facade and reducing the impact that high winds had on these early towers.
By the 1960's however, larger, box-like skyscrapers began to come to prevalence, bringing with them a whole host of wind load engineering challenges.
The first problem that began to arise was increased wind velocity at street level.
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