Why is a lower strength reduction factor (φ) used for COLUMN than a BEAM? | ACI-318 | Column vs Beam скачать в хорошем качестве

Why is a lower strength reduction factor (φ) used for COLUMN than a BEAM? | ACI-318 | Column vs Beam

Why is a lower strength reduction factor (φ) used for COLUMN than a BEAM? | ACI-318 | Column vs Beam IN this video lecture we are going to discuss the reasons for taking a small value of strength reduction factor for the column as compared to the beam in the ACI-318 design method. The Strength Reduction Factor (φ) is used in the ACI design method to reduce the estimated strength of the material. For beam, its value is generally taken as 0.90. While for the column the value of the strength reduction factor is 0.65 (Tied column) and 0.75 (Spiral column) Reasons for taking a small value of strength reduction for column as compared to beam: Beams are primarily moment resitting members, while columns are mainly subjected to axial loading. The column is a compression-controlled member while the beam is tension controlled member. The failure pattern of the column is brittle, while the failure pattern of the beam is ductile. Brittle failure is abrupt, while ductile failure gives a warning and involves plastic deformation. Column brittle failure is more critical than that ductile beam failure. Flexural failure is well understood and flexural strength can be calculated accurately. Column axial compression results in complex stresses, which can be determined by interaction diagrams, and are not well understood like the flexural failure of beam. The strength Reduction factor (φ) for the beam is more (0.90) And less for column 0.65 for tied column 0.75 for the Spiral column #ACI318 #strengthreductionfactor #Beam #Column #Design #civilengineer