Question 1

What standard rebar designations are in the AXIS database?

Accepted Answer

AXIS includes metric SI bars (Ø8 to Ø40, per ISO/EN) and US customary bars (#3 to #18, per ASTM A615/A706), with diameter, cross-sectional area, and mass per meter for each.

Question 2

What is the cross-sectional area of a Ø25 mm rebar?

Accepted Answer

A Ø25 (25 mm diameter) bar has an area of π×25²/4 = 491 mm². In US designation, this is approximately a #8 bar (1 in. nominal diameter, As = 0.79 in²).

Question 3

What is the unit weight of steel rebar?

Accepted Answer

Steel unit weight is 7,850 kg/m³ (7.85 g/cm³). A Ø16 bar has mass = π×0.016²/4 × 7850 = 1.578 kg/m. Mass per meter = 0.00617 × d² (kg/m) where d is diameter in mm.

Question 4

What is the development length for a Ø20 bar in normal-weight concrete (f'c=28 MPa, fy=420 MPa)?

Accepted Answer

Using simplified ACI 318-19 formula without modification factors: ld = (fy × ψt × ψe)/(1.1 λ √f'c) × db = (420 × 1.0 × 1.0)/(1.1 × 1.0 × √28) × 20 ≈ 1,440 mm. Full calculation requires checking cover and spacing conditions.

Question 5

What is the difference between Grade 60 and Grade 420 rebar?

Accepted Answer

They are equivalent: Grade 60 uses US customary units (fy = 60 ksi) while Grade 420 uses SI units (fy = 420 MPa). Both designations refer to ASTM A615 high-strength deformed reinforcing bar.

Size	db (mm)	Ab (mm²)	Perimeter (mm)	kg/m
Ø6	6	28.3	18.85	0.222
Ø8	8	50.3	25.13	0.395
Ø10	10	78.5	31.42	0.617
Ø12	12	113.1	37.70	0.888
Ø14	14	153.9	43.98	1.208
Ø16	16	201.1	50.27	1.578
Ø18	18	254.5	56.55	1.998
Ø20	20	314.2	62.83	2.466
Ø22	22	380.1	69.12	2.984
Ø25	25	490.9	78.54	3.853
Ø28	28	615.8	87.96	4.834
Ø32	32	804.2	100.53	6.313
Ø36	36	1017.9	113.10	7.990
Ø40	40	1256.6	125.66	9.864

Size	db (mm)	Ab (mm²)	Perimeter (mm)	kg/m
Ø6	6	28.3	18.85	0.222
Ø8	8	50.3	25.13	0.395
Ø10	10	78.5	31.42	0.617
Ø12	12	113.1	37.70	0.888
Ø14	14	153.9	43.98	1.208
Ø16	16	201.1	50.27	1.578
Ø18	18	254.5	56.55	1.998
Ø20	20	314.2	62.83	2.466
Ø22	22	380.1	69.12	2.984
Ø25	25	490.9	78.54	3.853
Ø28	28	615.8	87.96	4.834
Ø32	32	804.2	100.53	6.313
Ø36	36	1017.9	113.10	7.990
Ø40	40	1256.6	125.66	9.864

Rebar Database

Rebar Database

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Rebar Database

Rebar Database

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