4.14.2.9. FRPConfinedConcrete¶

uniaxialMaterial('FRPConfinedConcrete', matTag, fpc1, fpc2, epsc0, D, c, Ej, Sj, tj, eju, S, fyl, fyh, dlong, dtrans, Es, nu0, k, useBuck)

This command is used to construct a uniaxial Megalooikonomou-Monti-Santini concrete material object with degraded linear unloading/reloading stiffness according to the work of Karsan-Jirsa and no tensile strength.

`matTag` (int)	integer tag identifying material
`fpc1` (float)	concrete core compressive strength.
`fpc2` (float)	concrete cover compressive strength.
`epsc0` (float)	strain corresponding to unconfined concrete strength.
`D` (float)	diameter of the circular section.
`c` (float)	dimension of concrete cover (until the outer edge of steel stirrups)
`Ej` (float)	elastic modulus of the fiber reinforced polymer (FRP) jacket.
`Sj` (float)	clear spacing of the FRP strips - zero if FRP jacket is continuous.
`tj` (float)	total thickness of the FRP jacket.
`eju` (float)	rupture strain of the FRP jacket from tensile coupons.
`S` (float)	spacing of the steel spiral/stirrups.
`fyl` (float)	yielding strength of longitudinal steel bars.
`fyh` (float)	yielding strength of the steel spiral/stirrups.
`dlong` (float)	diameter of the longitudinal bars of the circular section.
`dtrans` (float)	diameter of the steel spiral/stirrups.
`Es` (float)	elastic modulus of steel.
`nu0` (float)	initial Poisson’s coefficient for concrete.
`k` (float)	reduction factor for the rupture strain of the FRP jacket, recommended values 0.5-0.8.
`useBuck` (float)	FRP jacket failure criterion due to buckling of longitudinal compressive steel bars (0 = not include it, 1= to include it).

Note

#.IMPORTANT: The units of the input parameters should be in MPa, N, mm. #.Concrete compressive strengths and the corresponding strain should be input as positive values. #.When rupture of FRP jacket occurs due to dilation of concrete (lateral concrete strain exceeding reduced rupture strain of FRP jacket), the analysis is not terminated. Only a message “FRP Rupture” is plotted on the screen. #.When $useBuck input parameter is on (equal to 1) and the model’s longitudinal steel buckling conditions are fulfilled, a message “Initiation of Buckling of Long.Bar under Compression” is plotted on the screen. #.When rupture of FRP jacket occurs due to its interaction with buckled longitudinal compressive steel bars, the analysis is not terminated. Only a message “FRP Rupture due to Buckling of Long.Bar under compression” is plotted on the screen.