aisi nheri diaphragm supplement - cfsei on-demand
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AISI NHERI Diaphragm Supplement
June 30, 2020 Update to AISI
Hernan Castaneda1 and Kara D. Peterman2
1Graduate Research Assistant, University of Massachusetts Amherst2Assistant Professor, University of Massachusetts Amherst
General Project Update
• We are all healthy and productive!
• Frontloading modeling efforts during Work From HomeJournal paper 1 (joist-ledger connections) on path to publication – coming soonThis summer, extended to full diaphragm system models predictions for future specimens
• Cantilever test rig (supported by SDI + Verco/Vulcraft) fabrication delayed due to COVID, design complete
Movement happening now things are opening up a bit
• Lab @UMass re-opened 06/22 at 25% capacity
• UCSD “latest and greatest” timeline: testing (in 6 DOF) Dec 2021/Jan 2022.
Brack Lab (UMass): Diaphragm Test Rig Top view
Fix End
Actuator
Free End
Specimen
Frame
Pin
Connection
RollerFront view
Strong
Floor
Brack Lab (UMass): Actuator and Roller Connection
Roller
Actuator
Bracket
Attachment
Support
Beam
Brack Lab (UMass): Rollers
Prevent
Uplift
Roller Dolly, Swivel
Platform, 25000 lb.
3 ¼" Wheel Dia.
• Roller support aimed
at 10% of actuator
capacity: 10 kips
Brack Lab (UMass): Rig – Fix Connection
Rig-Fixed Support
Brack Lab (UMass): Rig – Actuator Connection
Rig-Actuator
Brack Lab (UMass): Rig - Attachments
Rig-Specimen
Rig-Actuator Actuator-Support Beam Rig-Fixed Support
Brack Lab (UMass): Rig – Specimen Width Flexibility
Brack Lab (UMass): Test Rig [15’X15’] – Motion
• 10 in Stroke
• Δz = 0.26 in
• Tilt angle = 1° Click to play videos
Brack Lab (UMass): Test Rig [10’X15’] – Motion
• 10 in Stroke
• Δz = 0.26 in
• Tilt angle = 1° Click to play videos
Brack Lab (UMass): Test Rig
Fix Beam
Actuator
Support
Fix
Support
Free Beam
Transverse Beam
Roller
Support
Estimation of Weight, W:
Test Rig Frame
ComponentW
(lbs) (Kg)
Free Beam 2834 1286
Fix Beam 2558 1160
2 Transverse Beam 4019 1823
Total 9412 4269
Supports + Attachments + Plates
ComponentW
(lbs) (Kg)
Actuator Support 1002 455
2 Fix Support 1223 555
Roller Support 551 250
Total 2776 1259
Note:
- Weight is calculated assuming a density value of 0.2836 lbs/in3
- Nominal thickness of components varies between ¾” and ½”
- Some dimensions are approximated
Ledger
(1200T200-97)
Clip-Angle
(1.5X1.5-54)
Ledger
(1200T200-97)
Joist
(1200S200-97)
Diaphragm FEM 9/16” Deck on CFS Joist: Geometry
• Material properties steel:• Shell Elements: S4R
• A three-dimensional Finite Element Model (FEM) was developed using ABAQUS.
- E = 29500 ksi
- Fy = 50/60 ksi (EPP)
- ν = 0.3
Diaphragm FEM: Contact Interactions
• Contact behavior:
Clip-Angle
Ledger Web
Clip-Angle
Joist WebJoist Web
Ledger Web
Joist Flange
Ledger Flange
- Tangential:
C.O.F. = 0.2
- Normal:
Non-linear penetration pressure
Deck Side-Lap
Deck
Ledger Flange
Deck
Joist Flange
Diaphragm FEM: Fastener Connections• Connector elements:
- Wires
Clip-Angle
Ledger Web
(Screw #10)
Clip-Angle
Joist Web
(Screw #10)
Ledger Flange
Joist Flange
(Screw #10)
Ledger Flange
Joist Flange
(Screw #10)
Multi-Linear
Elastic
Damage Failure
Node
iNode
j
Connector Element Behavior
Shear
(Tao 2017)
Shear
(Tao 2017)
Pull-Out
(Castaneda 2020)
zx
y
Fastener elastic behavior
Fastener Pull-Out 97-54
2
1Fo
rce,
P [
kN
]
0
3
Displacement, δ [mm]
06 12 18
P1
P2
P3
Ppeak
Pfinal
9754-R1
9754-R2
9754-R3
ABAQUS
Experimental response
Support
Connection
(Screw #12)
Diaphragm FEM: Fastener Connections
Pattern 30/4
30”
Edge
Connection
@ 8” o.c.
(Screw #12)
Side-Lap
Connection
@ 12” o.c.
(Screw #10)
Support Connection Pattern
“Fix” strips
@ 2 ft o.c.
[Ux=Uy=Uz=0]
Load strips
[Uy=Uz=0; Ux=Applied Displacement]
Diaphragm FEM: Loading and Boundary Conditions
End Ledger Web
[Uz=0]
End Ledger Web
[Uz=0]
x
z
P
Diaphragm FEM: Results
Connector
Resultant Force
Stress Contour
Failure @
Corner Fastener
Failure @
Side-Lap Fastener
Diaphragm FEM: Results
• Effect on fastener
modeling shear behavior:
- Ductile: Consider post
peak experimental
response
- Brittle: Fastener
suddenly fails upon
reaching peak
experimental response
Diaphragm FEM: ResultsEdge Connection
@7.5”
Field Connection
@15”
3/8”
Diaphragm FEM: Results
Joist @ 2ft
Joist @ 4ft
Joist @ 8ft
Warping
Warping
Buckling
Diaphragm FEM: Results
Specimen 10ftX8ft: Joist @ 8ft
Ledger
Joist
Comments / Questions?
Email me: [email protected]