Steel Yield and Ultimate Strength

F_{y} = yield F_{u} = tensile strength

A36: Fy = 36 ksi, Fu ≈ 58–80 ksi. Grade 50 / A992: Fy = 50 ksi. Rebar Grade 60: fy = 60 ksi. Design uses Fy (steel) or fy (rebar) with φ. Fu is needed for fracture on net section (steel tension) and for Fu/Fy ductility checks.

$F_{y}$ (ksi): Yield strength
$F_{u}$ (ksi): Tensile strength

Step-by-step solved example

A36 bar Ag = 2.0 in². Yield load? Use Fy = 36 ksi.

Yield Fy and ultimate Fu on the steel σ–ε curve.

1. Py
Py = Fy Ag = 36×2.0 = 72 kip.
$P_{y} = 72 kip$

Answer: 72 kip

10 practice questions

0/10 correct

1.A36 Fy is

2.Grade 60 rebar fy is

3.Fu compared with Fy for mild steel is

4.A992 typical Fy is

5.Elongation and Fu/Fy indicate

6.fy = 420 MPa is about

7.E of steel is essentially the same for A36 and A992, about

8.Net-section fracture in tension uses

9.A higher carbon content typically

10.Stainless vs carbon steel: E is