The technology of planting bars is widely used in the reinforcement of concrete enlarged cross-sections. There are mature measures in the quality control of material selection, construction technology and practices, and it can carry out on-site pull-out tests in batches according to the design requirements.

In the reinforcement of planting bars, it is often encountered that the thickness of the base layer cannot meet the requirements of the planting bar depth, so it is necessary to recalculate the bearing capacity or adopt other anchoring measures for reinforcement.

Drawing lessons from the experimental research on the bending of beams of the planted bar system jointly completed by Horse Construction and Tongji University, the anchorage depth is closely related to the bearing capacity. It is recommended to consider the following points when recalculating the bearing capacity and considering reinforcement measures:

(1) The main cracks in the bending zone caused by stress concentration, with the increase of anchorage depth, the development of cracks tends to be sufficient and uniform.

(2) The flexural rigidity of the planted beam is not much different for different anchorage depths of the planted bar, but the ultimate bearing capacity is quite different. The cracking load of the beam also increases with the increase of the anchorage depth of the planting bars.

(3) Under the same conditions, the force of the steel bar when it fails under the bending force is much smaller than the force of the steel bar when the one-way drawing fails. Therefore, when the anchoring area of the planting bar is under a complex stress state, special attention should be paid to the influence of the stress state of the substrate on the anchoring performance of the planting bar, and the anchoring length of the planting bar must be appropriately increased.

(4) The results of the unidirectional pull-out test cannot be simply directly used to design the planting bar system of concrete members. Normally, the anchoring depth must be larger than that in the unidirectional pull-out case.

(5) The bonding surface of the new and old concrete is the weak part of the reinforced beam. Special attention should be paid to the roughening treatment of the bonding surface during the construction. The interface agent can be used for treatment. It is recommended to add additional tie bars.