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SUMMARY:Generalised Characteristic Length for Reinforced Concrete Beams - 
 Levinshan Nelson (CUED)
DTSTART:20101022T140000Z
DTEND:20101022T150000Z
UID:TALK27110@talks.cam.ac.uk
CONTACT:Nami Norman
DESCRIPTION:Shear strength reduction due to the size effect in internal bo
 nded steel reinforced concrete beams were dealt with a semi empirical rela
 tionship\, which were developed based on the experimental results. Size ef
 fect for other reinforced materials such as bonded and un-bonded FRP reinf
 orcement cannot be developed statistically due to limited numbers of exist
 ing experimental results. Therefore\, in the current work\, a new ‘gener
 alised characteristic length’ was developed theoretically in order to de
 termine the size effect in reinforced concrete beams irrespective of bond 
 condition and material properties of reinforcement. The model is developed
  based on mode I fracture crack bridging effect of concrete. The crack bri
 dging effect can be applied to both bonded internal and un-bonded external
  reinforcement. To validate the crack bridging effect of concrete\, a seri
 es of mode I three-point bending experiments was undertaken.\n\nThe propos
 ed generalised characteristic length depends on the concrete material\, th
 e shape of the beam\, the shape of the stress distribution in the fracture
  process zone and the force in the reinforcement. It was identified that t
 he generalised characteristic length varies as the crack propagates. The g
 eneralised characteristic length was compared with existing experimental r
 esults for beams with or without longitudinal reinforcement. Based on the 
 experimental validation\, it was shown that the generalised characteristic
  length can be applied to beams which fail due to the propagation of a ver
 tical or inclined crack. Moreover\, it was concluded that the size effect 
 reduction factor depends on the crack bridging force in the reinforcement 
 across a crack which implicitly depends on the bond properties between the
  reinforcement and concrete\, the type of reinforcement and the area of re
 inforcement.\n\n
LOCATION:Engineering Department - **LR10**
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