What is the section modulus of Pipe1-1/4XS?

Sx = 0.278 inÃÂÃÂ³, Zx = 0.393 inÃÂÃÂ³ (strong axis). Sy = 0.278 inÃÂÃÂ³, Zy = 0.393 inÃÂÃÂ³ (weak axis).

What steel grade is standard for Pipe1-1/4XS?

ASTM A53 Grade B (Fy = 35 ksi) for pipe sections. Verify with mill certificate.

What is the moment of inertia of Pipe1-1/4XS?

Ix = 0.231 inÃÂ¢ÃÂÃÂ´ about the strong axis and Iy = 0.231 inÃÂ¢ÃÂÃÂ´ about the weak axis. The radius of gyration is rx = 0.528 in and ry = 0.528 in.

Pipe1-1/4XS Steel Pipe — Section Properties

Dimensions

Property	Value	Unit
Outer Diameter (OD)	1.66	42.2 mm
Wall Thickness (t)	0.191	4.9 mm
Area (A)	0.837 in²	5.4 cmÃÂÃÂ²
Weight	3 lb/ft	4.5 kg/m

Elastic Section Properties

Property	Strong Axis (X-X)	Weak Axis (Y-Y)	Unit
Moment of Inertia (I)	0.231	0.231	in⁴
Elastic Section Modulus (S)	0.278	0.278	in³
Plastic Section Modulus (Z)	0.393	0.393	in³
Radius of Gyration (r)	0.528	0.528	in

Torsional Properties

Property	Value	Unit
Torsional Constant (J)	0.462	in⁴
Warping Constant (Cw)	0	in⁶

Section Profile Summary

This is a standard hot-rolled section profile covered by AISC 360. The tabulated section properties are computed from the nominal dimensions per the governing material standard. With Ix = 0.231 in⁴, the strong-axis flexural stiffness is suitable for preliminary sizing of beams and beam-columns.

Key Design Checks (AISC 360)

Check	Formula	This Section
Plastic moment	Mp = Zx × Fy	19.65 kip-in
Deflection	Δ = 5wLÃÂ¢ÃÂÃÂ´/(384EIx)	Use Ix = 0.231 in⁴
Torsion	St. Venant = GJ/L	J = 0.462 in⁴
Column buckling	KL/r ÃÂ¢ÃÂÃÂ Fcr	r_x = 0.528 in

Design Notes

Compactness: Verify flange and web slenderness against AISC 360 Table B4.1 classification limits for the governing load case (pure compression, pure flexure, or combined).
Combined loading: For members under simultaneous axial force and bending, use the interaction equations in AISC 360 Section H. The governing equation depends on the ratio of required to available axial strength.
Connection limit states: Check bolt bearing, tear-out, block shear, and weld strength at all connections. The governing connection limit state often controls the member size selection.

Verification (AISC 360): All designs using this section must be verified by a licensed Professional Engineer. Before finalizing member selection, check beam-column interaction (P-M), lateral-torsional buckling, serviceability deflections, and all connection limit states. See Engineering Disclaimer.

Related Resources

Design Resources

Section Properties Lookup — Compare with similar sections
Steel Beam Sizes Reference — Standard beam dimensions

Educational reference only. Verify all section properties against the current AISC 360 Manual and mill certificates before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.