Square and Rectangular Sections

Confinement with composite materials of square or rectangular sections only leads to limited increases in the member compressive strength. Consequently, this kind of application should be carefully assessed and analyzed. 

Before laying up the strengthening system, the cross-section edges should be rounded in order to prevent dangerous stress concentrations around them that could lead to premature failure of the system. 

The comer radius should satisfy the following limitation  

The regulations for the strengthening geometric ratio, Pf, to be adopted in the evaluation of effective confinement pressure, provide the following  

In the case of continuous wrapping, the expression of pf indicated under (5.23) becomes  

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Figure 2.13 (a) Beam under elastic flexure (three-point bending) (b) two beams with identical section area but different shape (square and rectangular section). 

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