Double-layer bidirectional reinforcement: the short direction of the lower layer steel mesh is below and the long direction is above; The upper steel wire mesh has a long bottom and a short top. If it is the upper negative reinforcement (commonly known as buckle reinforcement or set reinforcement), its placement position is not determined according to the length, but according to the reinforcement position of the beam where it is located. Because the two beams intersect, the gluten is up and down, so we should lower the buckle first, and then the position is slightly higher.