1Extract from fib T 2.9 Fastenings, Washington April 2015www.anchorprofi.de

Limitations of rigid base plate assumption

for calculating the anchor tensile forces

Longfei Li

2Extract from fib T 2.9 Fastenings, Washington April 2015www.anchorprofi.de

Estimate of safety reserves of the 3 tested anchorages of university Stuttgart related to rigid base plate assumption

Conditions for estimate:

1. The pull-out failure of the highest loaded anchor is decisive for the design.

2. The utilization of anchor resistance in ULS of the highest loaded anchor is equal to 100%.

3. The global safety factor for ULS amounts

γ = 1,4 ∙ 1,5 =2,1

1,4: Partial safety factor for action loads1,5: Partial safety factor anchor material

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 3

Estimate for tested anchorage 1

Test 1 , investigated by Fichtner/Eligehausen with bonded anchors

Compression Force F [kN]

Anchor

Tensio

n F

orc

e [

kN

]

CalculationRigid plateAnchor 1, 2

Anchor 1, 2

Test resultsAnchor 1, 2

Anchor 1, 2

Under design load F = 25 kN:Tested anchor force

Calculated anchor force= 62.5/36.3=1.72

Test results from the dissertation of Fichtner 2011

Safety reserve ∆γ = 2,1 – 1,72 = 0,38

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 4

Design example of tested anchorage 1, rigid base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 5

Design results of tested anchorage 1, rigid base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 6

Design example of tested anchorage 1, elastic base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 7

Design results of tested anchorage 1, elastic base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 8

Test 2 , investigated by Fichtner/EligehausenBase plate thickness t = 40 mm, bonded anchors

Compression Force F [kN]

Anchor

Tensio

n F

orc

e [

kN

]

CalculationRigid plateAnchor 1, 2

Test resultsAnchor 1, 2

Anchor 1, 2

M=F • ll = 1 m

F

M

Under design load F = 50 kN:Tested anchor force

Calculated anchor force= 96/40.8=2.35

Test results and photo from the dissertation of Fichtner 2011

Safety reserve ∆γ = 2,1 – 2,35 = -0,25

Estimate for tested anchorage 2

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 9

Design example of tested anchorage 2, rigid base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 10

Design results of tested anchorage 2, rigid base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 11

Design example of tested anchorage 2, elastic base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 12

Design results of tested anchorage 2, elastic base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 13

Test 3 , investigated by Fichtner/Eligehausenbonded anchors

Compression Force F [kN]

Anchor

Tensio

n F

orc

e [

kN

]

CalculationRigid plateAnchor 1, 2

Test resultsAnchor 1, 2

CalculationRigid plateAnchor 3, 4

Compression Force Fwith lever arm 1.0 m

Test resultsAnchor 3, 4

Under design load F = 60 kN:Tested anchor force

Calculated anchor force= 78/21.9=3.56

Figure from the design software Anchor Profi of Dr. Li Anchor Profi GmbHTest results from the dissertation of Fichtner 2011

Safety reserve ∆γ = 2,1 – 3,56 = -1,46

Estimate for tested anchorage 3

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 14

Design example of tested anchorage 3, rigid base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 15

Design results of tested anchorage 2, rigid base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 16

Design example of tested anchorage 3, elastic base plate

www.anchorprofi.de Extract from fib T 2.9 Fastenings, Washington April 2015 17

Design results of tested anchorage 2, elastic base plate