To what demand does SAFE design the reinforcement?Įxtended Question: Does SAFE design the reinforcement to match demand parameters, or does it exceed these values by a certain margin? Further, is there a way to specify reinforcement such that demand is 85-90% of capacity?Īnswer: SAFE designs the reinforcement according to ultimate demands, as is common in practice. The program uses the largest ratio between minimum and any of the options selected above a), b) or c). Minimum reinforcing ratio used for cracking analysis applies regardless of the option selected for reinforcement source. One of the following three reinforcement sources may be selected:Ī) User specified, user needs to add rebar in both tension and compression regions as applicable to the entire slab as program will not use design reinforcement along with user specified reinforcement.ī) FEM based, design rebars will be used as reinforcing sourceĬ) Quick top and bottom tension reinforcing is self-explanatory. What slab reinforcement is used in nonlinear analysis?Īnswer: Cracked analysis uses rebars as defined in reinforcing source via run>cracking analysis options. Use the User-Specified Rebar option to analyze slab deflection. Use the Draw > Draw Slab Rebar option to model the reinforcement as required.Use the Quick Rebar Top/Bottom option to specify a fixed amount of reinforcement throughout the slab.Here, rebar from finite-element design is the default setting, which may be revised using either of the following methods: To begin, select Run > Cracking Analysis.

Can I overwrite the resultant design slab reinforcement to reduce deflection?Īnswer: Yes, various options are available for the redefinition of design reinforcement. Floor slabs should however behave as diaphragms to transfer in-plane forces. In fact, ACI prohibits such behavior in high seismic areas because flexural contribution from floor slabs may increase lateral stiffness to an unconservative extent. However, this is rarely the case in that floor slabs typically do not contribute to the lateral capacity of the system.

Should stiffness modifiers be applied to floor slabs?Īnswer: Stiffness modifiers need not be applied to floor slabs unless special conditions exist, such as when shear walls are close to one another and the shell object acts as a coupling/link beam. Additional information on long-term cracked-section analysis is available through the Cracked-section analysis article. Why do linear and nonlinear long-term cracked-analysis results differ?Įxtended Question: Since my load pattern, coefficients, and all other parameters are the same, why would I not get the same results?Īnswer: The principle of superposition does not apply during nonlinear analysis, therefore results will be different between linear and nonlinear applications.

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