Challenge the future

DelftUniversity ofTechnology

Extended Strip Model for slabs

subjected to a combination of loads

Eva Lantsoght, Cor van der Veen, Ane de Boer

2

One-way vs. two-way shear (1)

Beam shear, one-way shear Punching shear, two-way shear

• Punching shear over perimeter• Beam shear over

(effective) width

3

One-way vs. two-way shear (2)

• 3D representation of failure modes

4

Slab bridge under live loads

5

Strip Model (1)

• Alexander and Simmonds, 1990

• For slabs with concentrated load in middle

• Lower bound method: conservative

6

Strip Model (2)

7

Extended Strip Model (ESM)

• Effect of geometry• Effect of bending moment

diagram: L, aM

• Effect of torsion β• Effect of self-weight vDL

• Unequal loading of strips v1 and v2

• Size effect on wACI

8

Extended Strip Model for

combination of loads (1)

9

Extended Strip Model for

combination of loads (2)

ESM x sup y edgeP P P P P

, ,2 1x sag x ACI xP M w

, ,

22 1x

sup s x ACI x

v

dP M w

a

, ,2y s y ACI y DL dist

M

LP M w v v

L a

, ,

,

2 for

for

s y ACI y DL dist w edge

M

edge

ACI y DL dist edge w edge

M

LM w v v l l

L aP

Lw v v l l l

L a

1

3

,

100mm0.166ACI x y ckw d f

d

1

3

,

100mm0.166ACI y x ckw d f

d

,

,

2 s y

w

ACI y DL dist

M

Ml

Lw v v

L a

10

Comparison to experiments (1)

Comparison between experimental results and ESM, 23 experiments on slabs under combination of loads for validation

11

Comparison to experiments (2)

• Pconc/PESM:• Average: 1.47

• COV: 12.5%

• 5% lower bound: 1.17

• Safe and conservative

method for assessment

Test setup in Stevin II lab of Delft University of Technology

12

Summary & Conclusions

• Transition between one-way and two-

way shear

• Slabs under combination of loads =>

live load models

• Strip Model for concentric punching

shear, slab-column connections

• Extended Strip Model for slab bridges

• 23 experiments under combination of

loads for validation of ESM

• ESM provides safe lower bound for

assessment

13

Contact:

Eva Lantsoght

E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec

+31(0)152787449