I’m installing rebar with HY 200 into sand lightweight concrete (λ = 0.85). Why does PROFIS Rebar only let me use λ = 0.75 for the lightweight concrete modification factor?
*Posted on behalf of a Hilti customer.
Dear Customer,
thank you for your question. PROFIS Rebar calculations are based on ACI 318-11 development and splice provisions. ACI 318-11 Section 12.2.4(d) states: “where lightweight concrete is used, λ shall not exceed 0.75 unless fct is specified (see 8.6.1).” ACI 318-11 Section 8.6.1 defines the parameter fct “splitting tensile strength of lightweight concrete.” PROFIS Rebar functionality does not include the ability to input a value for fct; therefore, the lightweight concrete modification factor (λ) that can be input is limited to 0.75. Please feel free to reach out any time, if you need additional information.
Cheers
Randall