Rebar Specifications
Rebar Specifications
Rebar Specifications
Rebar Grades
o Specifications and Grading
o Weldability of a Rebar
Rebar Sizes
o The Nominal Size of a Rebar
o The Proper Way of Measuring a Plain Round Bar
o The Proper Way of Measuring a Rebar
Rebar Tolerances
o Weight Tolerance
o Length Tolerance
Rebar Specifications
o Mechanical Property Specifications
o Surface Deformations Specifications
o Table of Standard Weights
Our products are made in accordance with Philippine National Standards for Steel
Bars for Concrete Reinforcement, under PNS-49:2002.
The three grades under this specification – namely, Grades PNS 230, 275, and 415
–trace their roots to ASTM specifications. And the terms ‘Structural’, ‘Intermediate’,
and ‘High-tensile’ originated from earlier versions of ASTM-A615 but remained
unchanged in deference to custom and familiarity among users. The table below
provides a handy reference as to the common understanding in the market
regarding these grades.
Grade 60 / PNS 415 High-Tensile Grade Medium & High-rise Structures / Infrastructure
The three grades are distinguished by the different color markings painted at the
ends of each bar, as shown in the following table:
Weldability of a Rebar [Top]
It must be noted that, in the current PNS 49, rebars are further categorized into
‘weldable’ and ‘non-weldable’ grades. The difference between the two categories is
primarily rooted in their different chemical compositions and carbon equivalents
(CEQ). Despite the different nomenclatures and their connotations, both ‘Weldable’
and ‘Non-weldable’ grades can actually be welded. However, the relatively lower
carbon content and CEQ of the so-called ‘weldable’ grade does make it easier to
weld without having to worry about pre-heating and post-heating requirements and
procedures, that is a concern highlighted especially in temperate situations.
The standard sizes that the Company manufactures and sells are as follows: 10mm,
12mm, 16mm, 20mm, 25mm, 28mm, 32mm, and 36mm. For special orders, it can
also make 40mm and 50mm bars.
For both the plain round bar and the rebar, the word ‘size’ and nominal diameter
are used interchangeably.
For a rebar, alternatively known as a ‘deformed steel bar’, its ‘size’ specifically
refers to the size of a plain round bar having the same weight per meter as the
rebar.
A specific ‘size’ of plain round bar refers to its nominal diameter. This ‘size’ also
refers to the diameter of a circular plain round bar having a certain unit mass or
weight per meter.
A plain round bar and a rebar of the same ‘size’ will have the same unit mass or
weight per meter of bar.
For a plain round bar, determining its 'size' involves simply taking a direct physical
measurement of its diameter since its circular cross section should remain quite
uniform throughout its length. A plain round bar is considered to be dimensionally
acceptable if its diameter, as measured, falls within the dimensional tolerances
allowed by the Standard.
A rebar however is not measured in the same way as a plain round bar. Because of
its non-uniform cross section, a rebar must comply with the allowable ‘Variation in
Mass’ (VIM) in lieu of measurement of its diameter. Checking for this VIM involves
taking and weighing one meter of rebar and comparing the findings against the
standard value.
Because variation in cross sectional area occurs during hot rolling, a corresponding
variation in linear weight is to be expected. For this reason, PNS-49 provides for an
allowable ‘variation in mass’ (VIM) of ±6%, measured using one meter of rebar.
The cut length of a rebar varies as well because of shrinkage as it cools down. The
standard however limits this shrinkage, and the minimum lengths of the finished
rebar are shown below.
7.5 7.453
9.0 8.935
10.5 10.440
12.0 11.940
Our rebar comes in these commercial lengths: 6.0, 7.5, 9.0, 10.5, and 12.0 meters.
Special lengths of 13.5 and 15.0 meters are subject to special orders and
negotiations.
MECHANICAL PROPERTIES
Diameter of
Yield Tensile Elongation Pin (d =
Bending
Class Grade Strength, Strength, Specimen in 200mm, nominal
Angle
MPa min. MPa min. % min. diameter of
specimen)
D<25mm 18 3d
230 230 390 180
Hot-Rolled D≥25mm 16 4d
Non-
D<25mm 10 4d
Weldable 275 275 480 180
D≥25mm 8 5d
Deformed
Steel Bar D<25mm 8 5d
415 415 620 180
D≥25mm 7 6d
D<25mm 20 3d
230 230 390 180
D≥25mm 18 4d
Hot-Rolled
Weldable D<25mm 16 4d
275 275 480 180
Deformed D≥25mm 14 5d
Bar
D<25mm 14 5d
415 415* 550** 180
D≥25mm 12 6d
* Maximum yield strength of Weldable steel bars shall not exceed 540 MPa
** Tensile strength shall not be less than 1.25 times the actual yield strength
DEFORMATION REQUIREMENTS
Height Tolerance of
Nominal Max. Average Spacing Lugs Max. Summation of Gaps
Diameter of Lugs (mm)
Minimum Maximum
10 7.0 0.4 0.8 7.8