BFRP bar as main reinforcement in concrete

[Iftikhar Hussain]

Would it be possible to design concrete structure in ETABS reinforced with FRPs rather than steel bars?

[abbaskhan2294]

If u r using both BFRP and Steel rebar in a section then u have to use section designer. But incase you're intending only to use BFRP instead of Steel rebars then its pretty simple. Define a rebar in materials properties then edit its properties with ur bfrp bars. Thats all you need to do.

[Iftikhar Hussain]

thank you for your response, but you know tensile strength of FRPs is 2 to 3 times of steel, and ETABS is compatible with steel up to 80ksi tensile strength, i have already checked this on continous beam. 

 

than how can i modify properties of steel to BFRP in etabs.

[abbaskhan2294]

Define a typical steel bar then edit its properties by inputting the properties of the BFRP. 

[Iftikhar Hussain]

ok,,, have you ever try this... if you have ETABS let me share some snap from there how can you modified steel properties to BFRPs.

thanks in advance 

[abbaskhan2294]

Sure. Here are the relevant snaps. Just put in all your BFRP properties for each parameter.

[Iftikhar Hussain]

thank you sir....

 

it helps alot 

[Ayesha]

I will suggest that you need to be little careful while working with high strength steel/ materials. How much care you need depends upon how high strength of the material is.

The reason - see figure below. I will be talking in terms of high strength steel. Most high strength steel materiel have very limited ductility so you don't want to hover around the 2% strain limit that we use with conventional rebar as you can see in the example image below as steel is already post yield at 2% strain. Generally while working with high strength rebars, you need to get the stress strain curve and then design the reinforcement based lower strain limit. Say a limit that represents 60% of yield as ductility is limited. Dywidag bars are another example that are used commonly in North America. You can see their stress strain properties here: https://www.dsiamerica.com/products/post-tensioning-systems/bar-post-tensioning-system/steel-stress-level/

Edited October 1, 2019 by Ayesha

[Iftikhar Hussain]

thanks for your concern...Actually FRPs have different sort of responeses in term of deflection, shear and momemt (in concrete). Similarly having different mechanical property than steel. For FRPs ACI 440 IR 06 have fixed some reduction factor which should be consider during designing of structure exposed to different environmental impacts. ETABS and SAP2000 till now not compatible to design members reinforced with FRPS. 

 

while high strength steel us on another side. ETABS version upto 9.7 were start giving same if you increase tensile strnght of steel more than 80ksi. but for new version i m not sure.. 

 

here for this particular case i think the only solution is to model FRPs material or section reinforced with FRPs and import to ETABS.