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Challenge the future
Delft
University of
Technology
Extended Strip Model for slabs
subjected to a combination of loads
Eva...
2
One-way vs. two-way shear (1)
Beam shear, one-way shear Punching shear, two-way shear
• Punching shear over
perimeter
• ...
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:
conser...
6
Strip Model (2)
7
Extended Strip Model (ESM)
• Effect of geometry
• Effect of bending moment
diagram: L, aM
• Effect of torsion β
• Effect...
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 
  ...
10
Comparison to experiments (1)
Comparison between experimental results and ESM, 23 experiments on slabs
under combinatio...
11
Comparison to experiments (2)
• Pconc/PESM:
• Average: 1.47
• COV: 12.5%
• 5% lower bound: 1.17
• Safe and conservative...
12
Summary & Conclusions
• Transition between one-way and two-
way shear
• Slabs under combination of loads =>
live load m...
13
Contact:
Eva Lantsoght
E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec
+31(0)152787449
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Extended Strip Model for slabs subjected to a combination of loads

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Reinforced concrete slab bridges are assessed for a combination of loads that include self-weight, superimposed loads, and distributed and concentrated live loads. The shear capacity of reinforced concrete slabs subjected to a combination of loads is thus an important topic for the assessment of existing bridges. Currently, a plastic model exists for the assessment of reinforced concrete solid slabs subjected to a concentrated load: the Extended Strip Model, based on the Strip Model for concentric punching shear. To apply this model to slabs subjected to a combination of loads, the model needs to be adapted based on theoretical principles. The results are then compared with the results from experiments on half-scale slab bridges subjected to a combination of a concentrated load close to the support and a line load. The result of this comparison is that the proposed method is suitable to find a safe estimate of the maximum concentrated load on the slab. The implication of this development is that an improved tool is available to estimate the maximum load of a truck that can be placed on a reinforced concrete bridge, thus improving the current assessment.

Published in: Engineering
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Extended Strip Model for slabs subjected to a combination of loads

  1. 1. Challenge the future Delft University of Technology Extended Strip Model for slabs subjected to a combination of loads Eva Lantsoght, Cor van der Veen, Ane de Boer
  2. 2. 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. 3. 3 One-way vs. two-way shear (2) • 3D representation of failure modes
  4. 4. 4 Slab bridge under live loads
  5. 5. 5 Strip Model (1) • Alexander and Simmonds, 1990 • For slabs with concentrated load in middle • Lower bound method: conservative
  6. 6. 6 Strip Model (2)
  7. 7. 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. 8. 8 Extended Strip Model for combination of loads (1)
  9. 9. 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    , , 2 2 1x sup s x ACI x v d P M w a    , ,2y s y ACI y DL dist M L P 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 L M w v v l l L a P L w v v l l l L a                        1 3 , 100mm 0.166ACI x y ckw d f d        1 3 , 100mm 0.166ACI y x ckw d f d          , , 2 s y w ACI y DL dist M M l L w v v L a     
  10. 10. 10 Comparison to experiments (1) Comparison between experimental results and ESM, 23 experiments on slabs under combination of loads for validation
  11. 11. 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. 12. 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. 13. 13 Contact: Eva Lantsoght E.O.L.Lantsoght@tudelft.nl // elantsoght@usfq.edu.ec +31(0)152787449

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