History of structures

eugene freyssinet

- pioneer of prestressed concrete -before frey used prestressing, needed to study and understand creep -issues -steel relaxation -concrete shortening and shrinking (shrinkage happens right away) -concrete creep (occurs after loads added over time) -started with just concrete arches then used prestressed -Le veurdre 1910 longest at time, knew about creep -boutiron bridge (still standing) -villeneuve sur lot bridge -st pierre du vauvray -plougastel arch (double deck) -luzancy bridge (first major PS bridge) no arch needed

Richard Bong bridge

-1985 opened -tied arch and lots of other spans

I-35

-8 lane over mississippi -111 vehicles and 18 construction workers fell -13 fatalities -was truss bridge -failure of one guset plate then collapse followed -bridge was undergoing deck repairs, adding construction loads and 20% more dead load from additional 2" of concrete -gusset plate issue was not found during design check or construction -designed to be replaced in 2020

cantilever

-A structure which is anchored at one end and can carry a load at the other end. -diving board

Aqueduct's

-Barton Aqueduct 1760 -Pontecysyllte aqueduct: much bigger, iron arches (efficiency and economy)

Othmar Ammann

-Bayonne Bridge (constant arch) -proposed Hudson river (George Washington) BR, vision for cars

Burj Khalifa

-Dubai, united arab emirates -william baker

Saint Anthony Falls bridge

-Figg (designer) -post-tension ?? bridge -underbudget -

Calatrava

-Spain -PhD in switz -elegance over economy and efficiency

Elastic theory

-THICK deck -rely on deck stiffness

Deflection theory

-THIN deck -rely on cable stiffness

John A Blantik bridge

-US 53 and I535 to connect DUluth to superior -openened in 1961 -replaced swinging toll bridge -repaired in 2011 (8gusset plates not meet load) -limited to 40 ton loads in 2008 -replaced in 2028 -structural art

pre-stressed concrete

-allowed for longer st -stretch steel, cast concrete over and let steel relax. Concrete now in compression or you can make concrete with hole in it already -allows for uncracked concrete that is level when load is on, prevents corrosion -put steel where there is tension

Fazlur Khan

-bangladesh -engineer -collab with goldsmith and graham -most of his career at SOM -most famous: JOhn Hancock center chicago 1969, diagonal bracing

Washington monument

-bottom crafted -top engineered -stone -structure type: column -dominating force: gravity

Stephenson

-britannia bridge: boxy expensive -built the walkway on ground and lifted iron box beam

chillon viaduct

-by piguet and associes -bridge above castle, only had to cut 3 trees down -

tradition of modern structural engineer

-calculations: predict performance -field experience: invent construction processes -imagination: create new forms

Concrete Components

-cement (10&) -water -sand -gravel -air

start of skyscraper

-chicago fire, during revolution when buildings of wood going up crazy -not really following code -rebuilt chicago

Reinforced concrete

-concrete good in compression not in tension -steel reinforcement for tensile stresses -steel goes where there's tension (where concrete is bending

leiter building

-dematerializing the wall, -> letting light in -beginning of skeletal urban form

Gustave Eiffel

-eiffel tower -Viaduct at Rouzat: 1st bridge to reflect wind -Pia Maria bridge: deck merges into top of arch -Garabit Viaduct: deck is above the arch

Tacoma Narrows

-extremely thin deck -failed because the deflection theory pushed too far

gustave magnel

-first professor to teach pre-stress -magnel and walnut lane mem bridge (1st prestressed bridge in USA)

Robert Maillart

-first to really understand and use steel and concrete -had the same teachers as Amann -from switz -Stauffacher bridge 1899: designed to look like renaissance bridge, 3 hinge arch -zouz bridge 1901: inside of arch is hollow, uses 1/3 material and is stiffer and stronger -tavanasa bridge: used limited concrete, high art word said ugly and he didnt try that style again -Salginatobel: used sketch from tavanasa, 3 hinge arch, limited material, won competition for being cheapest,

Christian Menn

-from the Graubunden -father was CE (knew Maillart professionally) -professor in ETH -imitation: Maillart -Crestawald bridge (deck-stiff arch) -Letziwald bridge -Crot (deck-stiff arch) Insipired by kloster bridge by Maillart, used prestressed concrete to span 3x distance -Nanin bridge -cascella bridge -salvanei bridge: realized that prestressing could replace the arch -imitation in prestressed concrete: -Felsenau bridge (competition) -ganter bridge -sunniberg: (slender, think deck) -zakim bunker hill bridge (boston)

Pierre Lardy

-graduated from ETH, math teacher in shiers, returned to zurich, professor in Zurich -Christian Menn and Heinz ISler were his students

Eiffel tower

-high art world signed petition to not build tower. -Eiffel financed tower and planned to move it after 20 years and collect concessions -withing first year he got 3/4 of its cost -iron -dominating force wind -structure type: cantilever

Duluth

-into 1900 more millionares in duluth than anywhere in US -

Sears tower

-large prefabricated sections -

John Roebling

-left Germany and lived in farming community in PA became engineer for state, became wealthy from wire rope -economic security led him to build suspension bridges -Brooklyn bridge -cincinnati bridge

prestressed concrete

-loaded so as to cause stresses opposite in direction from those caused by dead and live loads. -concrete in compression -steel in tension -in parking garages -can be much thinner

felsenau

-new form -double columns -prestressing in 2 directions play: single box girder with over hangs, curved roadway

ulrich finsterwalder

-new mangfall bridge (replaced bridge) prestress -really cool can walk inside -didnt think it could be done -after 1951 prestressed (post tension) cantilever -nibelugen bridge (first prestressed concrete bridge over Rhine)

post-tensioning

-pre-stressed concrete usually between some sort of wall but post-stress puts anchors on each side

moment diagram

-shape of eiffel tower -moment highest at bottom

reinforced concrete

-steel reinforcing bars have been embedded to

Telford

-structural engineer started as stonemason -first president of engineering society, considered himself an artist -first bridge age 30 -famous for stone bridges then flood came and only iron survived so he focused on iron -quote that resembles the EEE -learned from his bridges -Buildwas bridge: lack of transparency on how loads were carried -London bridge: designs single arch for competition -Menai bridge: concerned about wind, used cables -Craigellachie

Washington roebling

-took over construction of cincinnati bridge

Lift bridge

-transporter bridge in 1905 -reconstructed as lift bridge in 1930 -is structural art

WTC

-tube with core -Boeing 767 wingspan = 156' tower width 208 -was designed for plane impact but airplanes at the time were not that large -Gene corley led investigation -impact of plane caused damage to columns -high temp fire from jet duel reduced stiffness of steel trusses separating them from the remaining tube columns -steel did not melt -fire proofing met code but wasnt designed for prolonged level 0we could deisgn for every possibility but loss of economy aesthetics and livability

crete

-when concrete continues to stretch under its own weight

CIticorp building

-william lemeissser -designed around church -not designed for corner wind loads -

Brunel

-won the bridge competition over Thames (London bridge) -paddington station -saltash bridge: lenticular tress- arch that looks like an eye

order of materials used through history

1. iron (wrought or cast) 2. structural steel 3. reinforced concrete 4. prestressed concrete

skyscraper competition

1.first chicago school, 1871-1893 wainwright building (louis sullivan) 2.empire state building: 1912-1931 -102 stories -tallest for 40 years -Cass gilbert 3. second chicago school -1964-1985 Khan

sept 11

4 planes hijacked AA flight 11 hit north tower US flight 175 hit south tower AA flight 77 hit pentagonUA flight 93 crashes in PA

truss

A structure made of short, straight members organized into triangles. -beams that hold together

Quebec Bridge

An inexperienced engineer was left in charge of overseeing construction of a bridge that resulted in the collapse of part of the bridge, killing 76 workers. -first human error

Art of structural design

Efficiency Economy Elegance David Billington defined structural art

SCIENTIFIC

Eiffel: -iron -dominating force wind -structure type: cantilever Wash: -stone -structure type: column -dominating force: gravity

SYMBOLIC:

Eiffel: many pieces one tower Wash: many pieces one monument

structural artist evolved

From: imitation To: innovation and finally to: inspiration

Brooklyn bridge

SCI: gravity + wind SOC: politics (boss tweed) + cost, brooklyn connect to NY SYMB: presidential opening -suspension bridge that also includes cables stays: little wires holding deck bridge helping wind

Firth of forth bridge

SCI: horizontal cantilever SOC: response to firth of tay collapse SYMB; visual perspective -longest spanning bridge at the time -RR bridge -follows moment diagram but horizontal

Eads bridge

SCI: tressed arch SOC: chicago vs st Louis and the RR SYMB: hope for economic dominance -Jamess B Eads

Lenticular tress bridge

Saltash (Brunel) firth of forth ( Baker)

Why was there vertical cracking in the walls of the Zuoz Bridge?

Tension in the wall due to the difference in movement due to temperature differences between the top deck and bottom arch

column

Washington monument

structures are designed to carry more load than they should carry. If they fail, they are designed to do so in

a ductile failure so there is warning

torsion

act of twisting; stress due to twisting forces

steel reinforcement is used in concrete to primarily provide

additional tensile capacity

hinge

allows rotation

bridges consist of

bridges and arches

Industrial revolution

change in material: wood/stone -> iron change in power: animal -> steam

Caisson

floated into water sank to bottom, workers inside dig to keep sinking, workers stack stone on towers on top further sinking it

Taller towers

have smaller force on cables

most efficient shape for arch bridge

parabolic

compression

squeeze

tension

stress that occurs when forces act to stretch an object

tension

stretch

cables are in

tension

ductility

the ability of a substance to be pulled into a wire

first iron bridge

the iron bridge 1779 Abraham Darby SCI: new material SOC: Industrialization SYMB: structural art -intended to be an advertisement to ironmakers

shell

thin sometimes a dome

beams

under bridges

SYMBOLIC

washington monument: end of Am. Rev rise of dem Eiffel: end of French rev

stress

weight of structure/ footprint of tower force/area