I. A complete set of building reinforcement symbols.

Steel reinforcement is mainly divided into Grade I, Grade II, and Grade III. There are many ways to express steel reinforcement symbols, which vary depending on the construction. Below, we'll look at an encyclopedia of building reinforcement symbols to provide a useful reference for marking reinforcement.

Steel Reinforcement Type Symbols.

Steel reinforcement used in reinforced concrete structures includes hot-rolled steel reinforcement, waste heat-treated steel reinforcement, steel strand, cold-rolled ribbed steel reinforcement, cold-drawn steel reinforcement, cold-drawn steel wire, and cold-rolled twisted steel reinforcement. Hot-rolled steel reinforcement is a finished steel reinforcement formed by hot rolling and natural cooling, and is divided into hot-rolled round steel and hot-rolled ribbed steel. Cold-rolled ribbed steel reinforcement is a type of steel reinforcement with a crescent shape on two or three sides, formed by multiple cold rolling reductions, one rib pressing, and stress relief from hot-rolled wire rod.

The residual stress in hot-rolled and cold-rolled steel profiles is generated by different reasons, and therefore their distribution on the cross-section is also very different. Cold-rolled steel profiles allow for local buckling of the cross-section, thus fully utilizing the post-buckling bearing capacity of the reinforcement. However, local buckling of hot-rolled steel is not allowed. Hot-rolled steel has a higher free torsional stiffness than cold-rolled steel, therefore its torsional performance is superior.

Hot-rolled steel bar grade and diameter symbols.

This method of representing steel bars is mainly based on their shape, properties, and grade. It can be seen that steel bars have many different properties and grades. These issues should be considered when purchasing steel bars.

Steel bar markings.

Generally, during construction, we still express the required quantity and size of the steel bars, as well as their diameter, using the method described above to ensure accuracy during construction.

Generally reinforced steel bar markings.

The above are the symbols for generally reinforced steel bars. What are some commonly used component codes for steel bars? Next, we will continue to explore this topic.

The image above shows some commonly used steel bar component codes, such as B for slabs and WJ for roof trusses. These codes are simple to remember and widely used in building engineering.

Common classifications of steel bars.

There are many types of reinforcing bars, usually classified according to chemical composition, production process, rolling shape, supply form, diameter, and structural application:

(I) According to rolling shape.

(1) Plain reinforcing bars: Grade I reinforcing bars (Q235 reinforcing bars) are all rolled into a plain circular cross-section, supplied as round plates with a diameter not exceeding 10mm and a length of 6m~12m.

(2) Ribbed reinforcing bars: There are three types: spiral, herringbone, and crescent. Generally, Grade II and III reinforcing bars are rolled into herringbone shapes, while Grade IV reinforcing bars are rolled into spiral or crescent shapes.

(3) Steel wire (including low-carbon steel wire and carbon steel wire) and steel strand.

(4) Cold-rolled twisted reinforcing bars: Cold-rolled twisted reinforcing bars.

(2) Divided by diameter.

Steel wire (diameter 3~5 mm), thin reinforcing bars (diameter 6~10 mm), and thick reinforcing bars (diameter 22 mm and above).

(3) According to mechanical properties.

Grade 1 steel bars (235/370); Grade 2 steel bars (335/510); Grade 3 steel bars (370/570) and Grade 4 steel bars (540/835).

(IV) By production process.

Hot-rolled, cold-rolled, and cold-drawn steel bars, as well as heat-treated steel bars made from Grade 4 steel bars, have higher strength than the former. (5) Divided into compression steel bars, tension steel bars, vertical steel bars, distribution steel bars, stirrups, etc.

Currently commonly used steel bar models and corresponding grades. For example, No. 8 steel bar is Grade 1 steel, but what about No. 10, No. 14, No. 16, No. 20, and No. 22 steel bars? These generally use Grade 2 steel, while those generally use Grade 3 steel.

Grade 1, Grade 2, and Grade 3 steel bars are material standards formulated by the state according to the needs of social production. Their yield strength, ultimate strength, elongation, cold bending, and weldability differ greatly, and the application positions of different grades of steel bars are also similar. The yield strength of Grade I steel is 235 MPa and the ultimate strength is 310 MPa; the yield strength of Grade II steel is 335 MPa and the ultimate strength is 510 MPa; the yield strength of Grade III steel is 400 MPa and the ultimate strength is 600 MPa. HRB335 is Grade II steel and HRB400 is Grade III steel.