Strut and Tie Model

[Sanira]

Hello everyone,

I was wondering how everyone assumes the prismatic strut and bottle-shaped strut in Strut and Tie Design. For example, jn a beam, do you assume the horizontal strut as prismatic strut and the diagonal strut as bottle-shaped strut? Or is there any other logic involved. Thanks.

 

[Agent666]

Pretty much that's what I'd do for a deeper beam where the geometry exists where bottle shaped struts make sense. For a shallower beam the diagonals can probably be taken as more prismatic like I'd have thought?

 

[HTURKAK]

Prismatic struts are used when the stresses are uniform, for example , at the top of a member in positive bending. Bottle-shaped struts are located when the compressive stresses tend to spread laterally such as diagonal struts within a beam. The spreading of the compressive stresses produces tensile stresses which causes diagonal cracks . Orthogonal reinforcement shall be provided for bottle-shaped struts to avoid cracks .
Just write prismatic and Bottle-Shaped Struts and searched the web, and found the typical picture at below.