Briefly explained Structure System of John Hancock Centre, Chicago- Framed Tubes (Braced Tube)

1. Building Construction
Amay Vikrama Chauhan
2/17
John Hancock Centre Chicago

2. Commonly used structural
systems
 Rigid frames
 Shear Wall-Frame Systems
 Framed-Tubes
Braced tubes
Tube in tube
Bundled tube
 Spinal wall system with outrigger & belt

4.  Location: Chicago, Illinois
 Project Year: 1969
 Project Area: 2.8-million-
square-feet
 Height: 1,127 feet
 Architecture and
Structure: Skidmore,
Owings & Merrill (SOM)
 Structural Engineer:
Fazlur R. Khan, SOM
 Material : Concrete
 Structural System:
Braced Tubes

5.  100 stories above
the ground
 343.7 meter / 1128
feet tall
 70 story office
building
 45 story residential
building

6. Distribution of forces throughout
 a system of
redistributing the
vertical and horizontal
loads by using exterior
cross
 Trussed tube system
handles the lateral
loads on the exterior of
the building
 diagonal bracing
redistributes lateral
loads evenly to the
exterior columns

7. Taper of the centre
 He also designed the
tower to taper (the floor
area gets smaller as
the building gets taller)
reducing the horizontal
(wind) loading on the
building
 Vortex shedding
frequencies wouldn’t
be able to come
together to produce an
effective amount of
dynamic force

8. Exterior Bracing
 The John Hancock Center was the first “trussed
tube” structure utilizing exoskeletal members

10. Lateral Loads
Wind load:
 The building's tapered
form helps reduce
surface/wind loads
Seismic Load
 low risk seismic zone
 was able to achieve
smaller beam and
girder sizes

11. Connection details
 Heavy gusset plates tie the diagonal bracing,
columns, and spandrel beams together
Members are ASTM A36 steel and gusset plates are
ASTM A441

12. Connection details
 Avoided field welding by prefabricating the joint
assemblies
Bolted the wide flange members in place

15. Citation
 https://sites.google.com/site/johnhancockcentera
e390/structure/drawings
 http://faculty.arch.tamu.edu/anichols/courses/appli
ed-architectural-structures/projects-
631/Files/JohnHancockCenter.pdf