Modulus of Elasticity

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Modulus of Elasticity

Hi Rick,

Per BDM 5.1.1.D, the unit weight of plain concrete (Wc) should be taken as 0.15 kcf for normal -weight concrete, and be calculated per AASHTO LRFD Section Therefore for fc'=4000 psi, Ec=3834 ksi.

But I noticed in PGSuper, there are a few places the Ec automatically shown as 4266 ksi when unit weight used to compute Ec is inputted as 0.15 kcf. This happens at pier and deck tab.

Thank you!

Rick Brice
The modulus of elasticity

The modulus of elasticity equation changed in 2015 interims to the LRFD 7th Edition.

Ec = 120,000(1)(0.15)^2(4)^0.33 = 4266ksi

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