Corbel design - strain compatibility concern

[Samuee]

Hi all,

I am now designing a corbel with 300mm breadth and 600mm deep.

I use the rationale of struct and tie model to design the corbel. However I encountered problem in strain compatibility.

During design I need to avoid stew reaching its yield capacity, the tension steel stress is calculated by finding the neutral axis first while it is relating to concrete ultimate strain in a struct and tie model.

Then it is also related to magnitude of gravity load acting on the corbel. If the load is small, the neutral axis will approach to the bottom, which is my case, this makes the stress of top tension reinforcement very large

My question is, can I deliberately lower the ultimate strain in concrete so as to lower the strain of top steel.

 

[HTURKAK]

The beam theory , (Saint-Venant’s principle; plain sections remain plain,the strain varies linearly with the depth ..) is not valid at points that are closer than the distance h to discontinuities in applied load , reaction or geometry.

Your STI model shall include column portions having height equal to column depth..

Just write (corbel strut and tie model ) and search the web... one of them is,

 

[KootK]

X2 for HTURKAK's recommendations. A corbel non-Bernoulli space and the strain compatibility associated with Bernoulli spaces doesn't strictly apply there.