2015-11-08 case study no. 1 - high rise willis tower

7/24/2019 2015-11-08 Case Study No. 1 - High Rise Willis Tower

1/11

Willis Tower, formerly Sears Tower

Quick Facts:

Location: 233 S. Wacker Drive,Chicago, Illinois, US

Architect: Bruce Graham, DesignPartner at Skidmore,!ings, " #erill $S..#%

Engineer: &a'lur (ahman )han o*S..#

Architectural Height: ++2. m

Floor Count: - store/s 0 31asement oors

uil!ing Foot "rint: 44ro5 --- m

2

#ross Floor Area: +6,--- m2

Leasa$le Floor Area: 373,--- m2

%etail S&aces: +3,-- m2

'se: Commercial, 8ce, Broadcast,

9i*est/le, :vents

(um$er of Lifts: -+ !ith 6 dou1le;decker li*ts

Conce&t:

Steel &rame


2/11

)ntro!uction

=he su1?ect o* this case stud/

is the Willis Tower, formerly Sears

Tower in Chicago, Illinois, US. It

!as once the tallest 1uilding in the

!orld, having an architectural

height of ++-. m !ith a oor

count o* ./0 1oors &lus 2

$asement 1oors. It held this

distinction *or more than t!ent/

/ears. It !as !esigne! $y ruce

#raham an! Fa3lur %ahman 4han

of Ski!more, 5wings, an! 6errill.

=he !esign $rief!as develo4ed 1/ the clients Sears (oe1uck and

Com4an/, a hugel/ 4ro@ta1le retail

com4an/ in the US. =he com4an/

!anted an e5clusive o8ce 1uilding and thus hired interior design com4an/

SLS En7ironetics to conduct detailed studies on the s4ace reAuirements o*

the com4an/. =his stud/ determined that Sears reAuired 0/,/// m of

o8ce s&ace!ith oors o* +67- m2 to accommodate its 3,--- em4lo/ees.

=o achieve this, Skidmore !ings and #errill, through &a'lur (ahman

)han, develo4ed a ne! *orm o* structural su44ort *or sk/scra4ers allo!ing

ne! 1uildings to 1e 1uilt to un4recedented heights the Bundled =u1e

Vicinity Map

Location Map


3/11

Structural S/stem. Because o* this 1reakthrough, Sears reali'ed that !hat

the/ !ant !as not an e5clusive o8ce 1uilding 1ut a taller 1uilding !ith

s4aces a1ove the levels occu4ied 1/ Sears leasa1le to tenants.

Conce&t

=he conce4t o* the 1uilding is the $un!le! tu$e. =he tu1e

s/stem comes *rom the idea that a structure can resist lateral

loads 1/ designing it as a hollow cantile7er &er&en!icular

to the groun!. =he 1undled tu1e is an evolution o* this idea.

Instead o* one tu1e, a 1uilding can 1e 1uilt as several tu1es

tied together to act as one structure to resist the lateral

*orces.

=his allo!ed lesser columns and there*ore less steel

consum4tion and 1etter economic e8cienc/. &urthermore,

sk/scra4ers no longer had to 1e

1o5;sha4ed.

In the Willis =o!er, nine $% structural

tu1es,E each 23 m across, are grou4ed together

as one rigid structure in a three;1/;three grid

arrangement. =he/ are strengthened through

truss connections.

=he darker lines in the diagram on the le*t

re4resent the truss connection.

Willis Tower Concept Sheet


4/11

Floor&lan

=he Willis =o!erFs oor 4lan comes in four

7ariationat dierent levels. &rom the ground oor

u4 to the 7-thstore/, the oor 4lan consists o* all the

nine $% structural tu1e. =he central tu1e acts as the

1uilding core !here the ma?orit/ o* the 1uilding

services and vertical circulation are located. =he to4

le*t and 1ottom right tu1es !ould terminate at the

7-thoor !hile the others continue. In the 66 thoor,

the to4 right and 1ottom le*t tu1es !ould terminate

leaving 1ehind a cruci*orm oor 4lan !hich !ould

e5tend u4 to the -thoor !here the center;to4 and

the center;1ottom tu1e !ould terminate leaving the t!o remaining tu1es to

e5tend u4 to the -thand @nal oor.

=here are two 9 reasons for this staggere! a&&roachH

First, Sear;s original &lan was to occu&y only one half of the

$uil!ing, lea7ing the other half for lease to tenants- Since tenants

!ould need much smaller s4aces than !hat Sears !ould need, it !ould onl/

make sense to create smaller and smaller oor 4lates. =he !a/ S..# did this

not onl/ solved the oor 4late issue, it also led to the creation o* more

4erimeter o8ces, a much more attractive sell in real;estate. Secon!, in a

1undled tu1e structure, it is o* 4aramount im4ortance to $alance the


5/11

!istri$ution of the loa!s es4eciall/ considering the structureFs

as/mmetrical design. s a solution, the design called *or a rotation of the

framingever/ @ve oors and the !iminishing of the 1oor &late si3e in

s4eci@c areas.


6/11

=he s4atial organi'ation is mostl/ o4en;4lan oor area. =ake note o* the4rominent 1uilding core $shaded in gra/% !here most 1uilding servicesincluding vertical circulation and su44ort *acilities are concentrated.

Figure 2 - 38th Floor PlanFigure 1 - roun! Floor Plan

Figure 3 - "3r! Floor Plan Figure # - 8"th Floor Plan


7/11

2< Form

=he resulting 3D *orm

o* the 1uilding is a strong

architectural statement

!hich roared skyscra&ers

no longer ha! to $e

s=uare>like. =he

as/mmetrical design

resulted in the *orm o* multi4le to!ers reaching u4 to the sk/.

=he $lack hori3ontal $an!s on the fa?a!eas scene on the diagram

re4resent the truss oors !hich act as the main hori'ontal connectors in the

1uildings. =he architects also *ound it convenient to 4lace the mechanical

services on these oors as illustrated 1/ the stacking diagram.

s *or st/le, the Willis to!er *ollo!ed the then reigning International

St/le, s4orting clean vertical lines and *enestration on the !hole 4erimeter o*

the 1uilding !all.


8/11

=hough

Sears !anted to

1uild higher, the

height !as

limited 1/ the

aviation authorit/

in the US *or

sa*et/ 4ur4oses.

uil!ing Skin

=he =o!er uses 9ight!eight Black nodi'ed luminum S4andrel Panels and

Bron'e;=inted Glare;(educing ision Glass *or its Building Skin. =hese !ere


9/11

standard in the industr/ at that time es4eciall/ in International St/le

Buildings and are not o* note as the/ are 1asic curtain !all details toda/.

@ertical Circulation

=he Willis =o!er em4lo/s a ./+>ca$ ele7ator system-=here are dierent

t/4es o* elevator used.


10/11

=here are !ou$le !eck shuttle ele7atorsserving sk/ lo11ies. =here are

single !eck ele7ators*or intra;'onal travel. =here are e&ress ele7ators

that take 6 seconds to reach an o1servation deck at the -3rd oor. It

em4lo/s the sky lo$$yconce4t. =here are sk/ lo11ies at level 3+ and levels

66;6J.


11/11

Sources

htt4HKK!!!.som.comK4ro?ectsK!illisLto!erL*ormerl/LsearsLto!er

htt4HKK!!!.!illisto!er.comK1uilding;in*ormationKhistor/;and;*acts

htt4HKK!!!.great1uildings.comK1uildingsKSearsL=o!er.html

htt4HKKkhan.4rinceton.eduKkhanSears.html

htt4HKK!!!.slideshare.netKneel-+Ksears;to!er

2015-11-08 case study no. 1 - high rise willis tower

Documents