An enduring Chicago landmark   芝加哥永恒地标

For decades the tallest building in the world, the 110-story Willis Tower (formerly Sears Tower) marked a major step in exemplifying and defining SOM’s belief that a building’s structure should inform its exterior profile.

110层高的威利斯大厦（原西尔斯大厦）曾是世界最高建筑数十年，它标志着SOM在建筑设计理念——在“建筑结构应体现其外观”方面迈出了重要一步。

The 4.5-million-square-foot tower was the headquarters for Sears, Roebuck & Co. from the time of its completion in 1973 until 1995, when the merchandiser relocated to suburban Chicago. The building’s design, flexible floor plan, and iconic stature have made it a premier address for a host of companies. Today, the tower is well-maintained and remains a center of activity in Chicago’s Loop.

这座450万平方英尺的大厦自1973年竣工以来，一直作为西尔斯百货公司的总部，直至1995年该公司迁至芝加哥郊区。其独特的设计、灵活的平面布局和标志性的气势使其成为众多企业的首选办公地点。如今，这座大厦维护良好，仍然是芝加哥环区的活动中心。

Pragmatic engineering   务实的工程设计

The iconic setback design of the structure was conceived in response to the original client’s space requirements: Sears wanted a building that incorporated not only large office floors, necessary for the company’s operations, but also a variety of smaller floors for tenants requiring less floor area.

标志性的退台式结构设计旨在满足最初客户的空间需求：西尔斯希望这座建筑不仅能容纳公司运营所需的大型办公楼层，还能容纳各种较小的办公楼层，以满足对建筑面积要求较低的租户的需求。

Pioneering the use of bundled tube construction, the basic structure consists of nine 75-foot-by-75-foot column-free square tubes at the base, forming a cellular-tube frame. The nine bundled structural tubes, each rigid within itself without internal supports, rest on reinforced concrete caissons that go down to bedrock. The tubes are bundled together as a closed square up to the first 50 stories, and then terminate at varying heights to create the tower’s distinctive, multi-tiered form.

该建筑开创性地采用了管束结构，其基本结构由九根75英尺（约23米）x 75英尺（约23米）长的无柱方管组成，构成蜂窝状管状框架。九根管束结构管本身坚固，无需内部支撑，支撑在钢筋混凝土沉箱上，沉箱一直延伸至基岩。这些管束在前50层以封闭的方形管束形式连接在一起，并终止在不同高度，从而形成了塔楼独特的多层造型。

The structural steel frame was pre-assembled in sections and then bolted into place on site. The lightweight building skin, a black aluminum and bronze-tinted glare-reducing glass, serves as an insulator between the interior and exterior structure in order to maintain a relatively constant temperature, which minimizes the expansion and contraction of the frame.

结构钢框架分段预制，然后在现场用螺栓固定到位。轻质建筑表皮由黑色铝材和古铜色防眩光玻璃构成，在内外结构之间起到隔热作用，以保持相对恒定的温度，从而最大限度地减少框架的膨胀和收缩。

Above the clouds   云端之上

In 2009, the Ledge at Willis Tower was created to enhance the building with an innovative new observation deck on the 103rd floor. In 2021, SOM continued its 50-year stewardship of Willis Tower with a transformative renovation of the Ledge. Interior enhancements, improved lighting, building technology upgrades and a new exhibition space further immerse visitors in Chicago’s historic skyline.

2009年，威利斯大厦的观景台（Ledge）落成，为大楼增添了创新的全新观景台，使其更加引人注目。 2021年，SOM延续了其对威利斯大厦50年的管理，对楼顶进行了革新性翻新。室内装修、照明升级、建筑技术升级以及全新的展览空间，让游客更加沉浸于芝加哥历史悠久的天际线之中。

Client：Sears Roebuck & Co.

Site Area: 3 acres

Building Height: 1,450 feet

Number of Stories: 110

Building Gross Area: 4,455,844 square feet

SEE MORE (来自)   SOM