Fall 2002Ben Schafer

thin-walled structures research group

Testing of cold-formed steel beams

• Jack Spangler• Jim Kelly• Cheng Yu• …most of the CE Grads• Sam Phillips• Liakos Ariston• Tim Ruth• Andrew Myers• …other CE undergrads• Michael Manness, Jr.

Cold-formed steel beamscheng yu

• Testing– first tests with definitive

separation of modes– upper and lower bound

flexural capacities– experimental evidence for

new design methods• FE Modeling

– parametric studies– moment gradient effect– influence of restraint

• Significant design impact

Distortional

Local

EA/GA and member optimizationsam phillips

Special: 2 hour “Short Course”Thursday September 26, 2002

1:00pm to 3:00pmShaffer Hall Room 101

Evolutionary Computation and Civil/Structural Engineering:A Look Back and a Look Forward

Assoc. Prof. Chris Foley Marquette University

collapse of thin-walled membersbadri hiriyur

Pxm

Px

Pcrx

o

xP̂

P

Pm

PPcr

o

P̂

P

Pm

PPcr

o

P̂

P

Pcrx

Pcr

P

Pxm

P m

(d) example full model response

(b) unstable sway mode

P

k

kx

kx

F

x

Fy

k

M

y

L/2

L/2

P

k

kx

kx

F

x

Fy

k

M

y

L/2

L/2

(a)bar-spring model (c) stable local mode

collapse of corrugated plastic pipe

X

Y

Z

V1L21C10

s y m m e t r y a lo n g e d g e s e n f o r c e d

s y m m e t r y e n f o r c e da t s p r in g l i n e

s y m m e t r y e n f o r c e da t c r o w n

c r o s s - s e c t io n

l i n e r

c r e s t

v a l l e y

X

Y Z

V1G4

Output Set: Step 1, Inc 19Deformed(1.354): Total Translation

generalized beam theorypuneet bajpai

Unifies the conventional theories

Better understanding of structural principles

Economical method of analysis

Capability to consider individual buckling modes and select combinations of them

Applicable to linear analysis (First-order GBT), linear stability analysis (General second-order GBT), or bifurcation problems

q VWVB VD GVCE kjiijk

ji

kkkkkk '''''''' )(

Basic equation of second-order theory :

where, E = Young’s modulus, G = shear modulus,

BDC kkk ,, = section properties applicable to mode k,

Vk = generalized deformation in mode k qk

= distributed load applicable to mode k,

= three dimensional array of second-order terms, which includes coupling terms ijk

Stochastic post-bucklingjie li, prof. lori graham

/c = 1 + a + b2 + …,

V = cV0 + (acV0 + V1) + (bcV0 + V2)2 + …

covered wooden bridgesdylan lamar (u of ark), erika stoddard, steve buonopane

Pine Grove Bridge - Lancaster Co., PA

Brown Bridge - Rutland Co., VT 

Reliability and advanced analysissteve buonopane, prof. tak igusa

Ziemian frame testbed problem Strength at first plastic hinge

no correlationto ult. strength

Ultimate Strength (via Adv. Anal.) Failure probability estimation

Solver efficiency for reliability and optimizationzailong wan, prof. dan naiman, prof. tak igusa

{F}=[Kt]{d}

[Kt]=

buildingbasic geom.basic loads

perf. criteria

building realization(s)input

MASTANinterface

deterministic response study seek efficiency through

topology•symm.•pos-def.•sparse•topology unchanging

wind on low-rise buildingsprof. nick jones

Hurricane Loss ReductionWind and Structural Engineering Initiative

through National Institute of Standards and Technology

Building and Fire Research LaboratoryGaithersburg, Maryland