October 12, 2022
1. Reinforcement sampling
Simply put, it is to calculate the total weight of reinforcement of an engineering project, and the result is generally how many tons. The weight of the steel bar is equal to the length of the steel bar times the specific gravity of the steel bar. Therefore, the sampling of the steel bar is actually to calculate the total length of the steel bar. The total length of the steel bar of different diameters times the corresponding specific gravity is the total weight of the steel bar. It's also the weight of a theory.
2. Concrete protective layer
Concrete protective layer: structural members of the reinforcement skeleton is poured in concrete, in the periphery of the reinforcement skeleton must have concrete will be wrapped around the reinforcement, the main reinforcement skin and concrete surface (that is, the outer surface of the component) between the distance, is the thickness of the concrete protective layer of reinforcement. Not less than 10mm.
3. Type of reinforcement
The reinforcement of reinforced concrete structure is divided into two categories of reinforcement and steel wire according to the diameter size. The diameter is above 6mm, and the steel wire is within 5mm.
The production process is divided into: hot rolled steel bar, waste heat treatment steel bar, cold drawn steel bar, cold drawn steel bar, cold rolled steel bar and so on.
Commonly used steel bar: (GB50010-2002)
HPB235(Hot rolled round bar, first class bar)
HRB335(Hot rolled ribbed Bar, Secondary bar)
HRB400(Hot rolled ribbed bar, third grade bar)
RRB400 (waste Heat treated rebar, Grade 3 rebar)
Grade 540 is grade 4 steel, the current specification has been cancelled.
4. Reinforcement connection
The rebar produced by the factory is made according to the fixed length size of certain specifications (such as 9 meters and 12 meters). In the actual project, the reinforcement used are long and short, different shapes, so it is necessary to deal with the reinforcement.
Connection methods include binding, welding (butt welding, single side welding, double side welding, electroslag pressure welding)
And mechanical connection (straight thread connection, taper thread connection, cold extrusion of casing)
5. Lap length of reinforcement
Connector length: Lle or Ll; Single-side welding: 10d Double-side welding: 5d
