- Rebar Grades
- Rebar Sizes
- The Nominal Size of a Rebar
- The Proper Way of Measuring a Plain Round Bar
- The Proper Way of Measuring a Rebar
- Rebar Tolerances
- Rebar Specifications
Rebar Grades [Top]
Our products are made in accordance with Philippine National Standards for Steel Bars for Concrete Reinforcement, under PNS-49:2002.
Specifications and Grading [Top]
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.
|ASTM vs PNS Codes||Popular Nomenclature||Typical Application|
|Grade 33 / PNS 230||Structural Grade||Low-rise Buildings and Low Loading Conditions|
|Grade 40 / PNS 275||Intermediate Grade||Medium-rise Structures / Infrastructure Work|
|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.
Rebar Sizes [Top]
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.
The Nominal Size of a Rebar [Top]
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.
The Proper Way of Measuring a Plain Round Bar [Top]
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.
The Proper Way of Measuring a Rebar [Top]
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.
Weight Tolerance [Top]
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.
Length Tolerance [Top]
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.
|Std. Length (m)||Min. Acceptable Length (m)|
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 Property Specifications [Top]
|Class||Grade||Yield Strength, MPa min.||Tensile Strength, MPa min.||Specimen||Elongation in 200mm, % min.||Bending Angle||Diameter of Pin (d = nominal diameter of specimen)|
|Hot-Rolled Non-Weldable Deformed Steel Bar||230||230||390||D<25mm|
|Hot-Rolled Weldable Deformed Bar||230||230||390||D<25mm|
* 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
Surface Deformations Specifications [Top]
|Nominal Diameter||Max. Average Spacing of Lugs||Height Tolerance of Lugs||Max. Summation of Gaps (mm)|
Table of Standard Weights [Top]
|STANDARD WEIGHT OF DEFORMED ROUND STEEL BARS|
|Bar Commercial Length|
|6.0 m||7.5 m||9.0 m||10.5 m||12.0 m|