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Wire strand reinforcement

Question
State
Description Text

color:#002060">I request your opinion on the attached Colorado DOT standard
detail.



color:#002060"> Question: Have you folks crash tested R.C. barrier using
wire strand



color:#002060"> (see note 8 sheet 1of4).

Keywords
  • Permanent Concrete Barriers
Other Keywords none
Date June 26, 2014
Attachment m-606-13-guardrail-type-7-f-shape-barrier.pdf - Adobe Acrobat Pro.pdf


Response
Response

We have never tested barriers using wire strand as the reinforcing steel but we believe it may be feasible. The closest thing we have seen to this is pre-stressing strands used in reinforced concrete design. in this case they are only used as reinforcement.

 

The strength of the specified strand appears to be equal or greater than the Grade 60 rebar, so that should not be an issue. We cannot see any direct reasons why it would not work, but we can note some potential differences between rebar and the wire strand.

1.       Development length may differ for the wire strand as compared to rebar and thus may change the interaction or bond to the concrete somewhat. It is difficult to say how different that would be, but it may affect the performance of the reinforcement to some level. You would need to consider this when splicing the strands or other areas where development of the reinforcement was critical.

2.       The modulus or elastic stiffness of the wire strand will be considerably less than that of the rebar due to the construction of the strand. Thus, while the strength of the rebar and strand are similar, the stiffness of the wire strand would be less. As the reinforcement severs mainly as a tension member, this may not affect ultimate capacity, but may change the flexural and longitudinal stiffness for the reinforced concrete section.

3.       The difference in the modulus of the rebar and the strand may lead to increased cracking under flexural loading  and temperature shifts.

 

Let me know if we can help you further.

 

Date June 27, 2014


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