A CASE STUDY OF A HIGH RISE BUILDING @SKYCRAPPER

1. Sears Tower
A MULTI USE URBAN PROJECT
BY
AKSHAYA.R
113614251004
SPCET - SOA

2. SearsTower
• 3.8 million rentable square feet (89acres)
• 159,000 square feet of retail space.(0.36acres)
• 160-car executive parking garage.
• Location: Chicago, Illinois
• Project Completion: 1974
• SiteArea: 3 acres
• Project Area: 4,565,844 ft2 (105acres)
• Number of Stories:110
• Building Height: 1,450 ft (442m)
• Market: Commercial +Office
second-tallest building in the United States
While 12th-tallest in the world
25,000 daily visitors12,000 occupants

4. SITE PLAN

5. SEARS TOWER

7. CHICAGO SKYLINE
SPRANDEL BEAM
SKYLINE OF WORLD HIGHEST SKYCRAPPERS

8. Forces andForm
• The Willis Tower draws its strength, both visual and physical, from its structural
form, the bundledtube.
• The building plan consists of 9 squares, each 75 feet across, placed in a three-
by-three grid arrangement.
• Each square has 5 columns per side spaced 15 feet on centers, with adjacent
squares sharing columns.
• As the columns rise up the building, each square in the plan forms a tube,
which can be seen on the exterior of thebuilding.
• Thesetubes are independently strong but are further strengthened by the
interactions between each other through trussconnections.
• While the tubes connect at each floor level with beams and floors trusses,
several large trussed levels act as the main horizontal connectors in the
buildings.
• These trussed levels, which also contain the mechanical systems for the
building, appear as black horizontal bands on the façade. While the louvres
covering the trussed levels mask the structural details, the purpose of these
levels remains abundantly clear visually.

9. • Theclosely spaced interior and exterior columns are tied at each floor with deep spandrel beams.
At the truss levels, these tubes are tiedtogether.
• Theseties resulted in astiffer structure, asthe building acts asaunified systemof stiffened
tubes.
• The interaction between the individual tubes and the belt trusses at mechanical levels allows the
building to attain its extremeheight.
• Due to the drop offs, the gravity loading on the system is not evenly distributed along the height
of the building.
• Thesetrusses take the gravity loads from above and redistribute them evenly onto the tubes
below.
• This is particularly important for the uppermost section of the tower, due to its asymmetry about
the central axisof thebuilding.
• The presence of the belt trusses help to mitigate these effects of differential settlement, which
causethe building to tilt.
Spandrel beams are load-bearing structural members around the perimeter of a floor of a building. Not only may they support loads from the roof and other floors, they may also help support a
building's walls. For example, walls expected to experience significant forces from wind may be anchored to these beams to better distribute theload.

10. INTERIORBEAMS ANDCOLUMNS
CONSTRUCTION – EXTERIOR VIEW

12. X bracing of the columns at themechanical
floors
29th – 32nd
64th – 65th
88th – 89th
104th – 108th

13. MILE STONES
• 1970 – THE CONSTRUCTION EFFORT BREAKS DOWN
• 1973 – 2000 WORKERS - CONSTRUCTION IS COMPLETE
• 1974 – SKYDECK OFFICIALLY OPEN TO PUBLIC
• 1984 - BROADCAST ANTENNAS ARE ADDED TO THE BUILDING
• 1985 – BUILDING UNDERGOES REVITILIZATION PROJECT, RECEIVES NEW ATRIUM
• 2000 – THE SKYDECK UNDERGOES A MULTI MILLION DOLLAR RENOVATION
• 2009 - SEARS TOWER IS OFFICIALLY RENAMED AS WILLIS TOWER
LED BY U.S EQUITIES,SKYDECK CHICAGO AT WILLIS TOWER DEBUTS NEW EXHIBIT
EXPERIENCE AND THE LEDGE
• 2015 - BLACKSTONE GROUP PURCHASES WILLIS TOWER FOR $1.3 BILLION MAKING IT THE LARGEST
RETAIL TRANSACTION IN THE CITY OF CHICAGO.EQUITY OFFICE TAKES OVER AS BUILDING
MANAGEMENT
• 2017 – VISIONARY PLANS FOR WILLIS TOWER’S $500MILLION REDEVELOPMENT ARE UNVIELED
TO PUBLIC
• 2018 – REDEVELOPMENT PLANS NOW UNDERWAY TO INCLUDE 150,00 SQ FT OF TENANT EXCLUSIVE
AMENITIES,REVAMPED WACKER AND FRANKLIN LOBBIES, MORE THAN 300,000 SQ FT
OF NEW RETAIL AND BASE BUILDING MODERNIZATION INCLUDING FULL REDESIGN
OF VERTICAL TRANSPORTATION.

14. VerticalCirculation
• TheSearsTower’s104-cab elevator systemdivides the building into three separate zones,with
skylobbies in between at levels 33-34 and66-67.
• 28 double decker expressshuttle shuttle elevators serve the skylobbies
• 63 single deck elevators for intra-zonaltravel
• 6 freight elevators
• Twoexpress elevators that take 61 secondsto reach the 1353 foot high skydeckat level 103
travelling at 1600 feet perminute.

15. 1,730 feet (527.3m)
1,450 feet (442.1m)
1,353 feet (412m)

16. 38th Floor Plan

17. 48th Floor Plan

18. 85th Floor Plan

19. 95th Floor Plan

20. • Theexterior skin of the building is an expression of thestructural
skeleton inside, with the fire proof frame sheathed in black
aluminium and glare reducing bronze tinted glass.
• Theexterior skin is maintained with yearly check ups and sixwindow
washing machines.
• The main draw back was wind force so they constructed steel frame
outside the building
• Which it withstands 90km/hr speed of wind

21. The Ledge at SkydeckChicago

22. Facts
Willis Tower hasafootprint that encompassesan entire square city block. It’s even itsown
zip code. Truly acity-within-a-city, you might be surprised to learn some of these stats
about the building:
• Willis Tower features 16,100windows and six roof-mounted robotic window washing
machines clean them.
• Willis Tower’s square footage is the equivalent of 101footballfields.
• It took 2,000 workers three years to build the tower.
• Approximately 43,000 miles (69,200 kilometers) of telephone cable runs throughthe
building - enough to stretch acrossthecontinental United States 15 times.
• Willis Tower weighs 222,000 tons.
• Theaverage swayof the building is approximately six inches (152 millimeters) from true
center, but the building is designed to sway up to three feet.
• Willis Tower elevators operate asfast as1,600 feet (488 meters) per minute - among the
fastest in the world.
• Eachworking day,between 15,000 and 20,000 people come and go from Willis Tower

23. Most interesting
• SkydeckChicagodebuted TheLedgein 2009, unveiling abreathtaking view
of the city, 1,353 feet straight down to Wacker Drive and the ChicagoRiver.
Sincethen, it hasbecome a“must-do” Chicagoexperience forlocals and
visitors alike.
• TheLedgefeatures glasspanels that are 1 ½inches thick and canhold5
tons.
• TheLedge’sglassboxesare designed to retract into the building,allowing
easyaccessfor cleaning and maintenance.
• Approximately 1.4 million people visit Skydeckeachyear, a30%increasein
attendance since the debut ofTheLedge.
• Onaclear day,you canseefour states from Skydeckon the 103rdfloor:
Illinois, Indiana, Wisconsin and Michigan. Visibility from theSkydeckis
approximately 40-50 miles (65 - 80kilometers).