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What Is Rebar?

Rebar, also known as ribbed steel bar, encompasses both hot-rolled and cold-rolled ribbed steel bars.

The grade of rebar is denoted by HRB, followed by its minimum yield point, and is divided into three categories: HRB335, HRB400, and HRB500.

For seismic reinforcement, an “E” is added to the ordinary reinforcement, such as HRB400E.

Note that the density of the billet used for rebar rolling is consistent at 7.85g/cm³, and thus, the theoretical weight of rebars of the same specifications will be the same, regardless of the rolling method or grade.

You can easily determine the weight of rebar steel through either our rebar weight calculator or by using the chart provided below.

Rebar Weight Fundamentals

Material Composition

When it comes to rebar weight, you need to consider the material composition. Rebar is short for “reinforcing bar,” and it is primarily made from steel. Steel is an alloy of iron and carbon, with trace amounts of other elements, such as manganese, silicon, and phosphorus. The weight of rebar is dependent on the density of the steel, which is typically around 7,850 kg/m³.

Rebar Types

In addition to material composition, the type of rebar also affects its weight. There are several types of rebar that you can use in a construction project. Below are some common rebar types:

1. Carbon Steel Rebar: This is the most common type of rebar and has a relatively high tensile strength. Carbon steel rebar comes in various grades and diameters, each with a different weight.
2. Welded Wire Fabric (WWF): This type of rebar looks like a mesh made of steel wires welded at each intersection. It is mainly used for reinforcing slabs and walls. WWF is available in different wire diameters, spacings, and weights.
3. Epoxy-Coated Rebar: This is a carbon steel rebar coated with epoxy to resist corrosion. It is often used in structures exposed to harsh environmental conditions, such as bridges and marine applications.
4. Stainless Steel Rebar: This type of rebar is known for its high resistance to corrosion and its ability to maintain structural integrity over time. It is heavier than carbon steel rebar, but it is also more expensive.

To calculate the weight of a specific type and length of rebar, you can use the following formula:

Weight = Length × Diameter² × 0.00617

Where Weight is in kilograms, Length is in meters, and Diameter is in millimeters. The factor 0.00617 is a constant derived from the density of steel and the conversion factor between square millimeters and square meters.

Here’s a brief example:

If you have a 12-meter long, 16-millimeter diameter carbon steel rebar, you can calculate its weight using the formula:

Weight = 12 × 16² × 0.00617 = 18.95 kg

By understanding rebar weight fundamentals, such as material composition and different rebar types, you can make informed decisions about the right type of rebar for your construction project.

Rebar Weight Calculator

Rebar Weight Chart

Note:

(1) Theoretical weight calculation formula of rebar: theoretical weight (kg/m) = 0.00617 × D² (where, D is the section diameter, unit: mm)
(2) The density is calculated as 7.85g/cm³;
(3) The theoretical weight of hot-rolled ribbed bars, cold-rolled ribbed bars, HRB335, HRB400, HRB500 and other deformed bars of different classifications is the same.
(4) The theoretical weight calculated by the formula is different from the actual weight, and the error is generally about 0.2% ~ 0.7%, which can only be used as a reference for estimation.

Weight of Reinforcement With Common Specifications

(weight per meter)

For example:

• Φ6=0.222Kg
• Φ8=0.395Kg
• Φ10=0.617Kg
• Φ12=0.888Kg
• Φ14=1.21Kg
• Φ16=1.58Kg
• Φ18=2Kg
• Φ20=2.47Kg
• Φ22=3Kg
• Φ25=3.86Kg
• Φ28=4.83Kg
• Φ32=6.31Kg
• Φ36=7.99Kg
• Φ40=9.87Kg

Specification of Rebar

The specifications of rebar are typically required to be listed in import and export trade contracts.

Usually, the rebar specifications should include the standard grade, nominal diameter, nominal weight, specified length, and allowable differences of the above indicators.

The standard nominal diameters for rebar are 6, 8, 10, 12, 16, 20, 25, 32, 40, and 50mm.

The supplied length of rebar can be either fixed length or multiple lengths.

The range of fixed length for rebar exported from China is 6-12m, while that of rebar exported from Japan is 3.5-10m. If there is no requirement specified in the contract for domestic rebar, its length is usually 9m or 12m.