2.
If the tensile strength of one test piece does not meet the requirements, another (6) test pieces shall be taken for re inspection.
The length of the connection section of the mechanical connection of the reinforcement shall be calculated as 35d.
The joints should be set at the parts with small tensile reinforcement stress of structural members.
The diameter change of the main reinforcement of the column is wrong, the section of the column is changed, and the end of the column is not standardized.
6.
2.
13.
The sampling quantity shall be 10%, and the inspection qualification rate shall not be less than 95%.
When the column longitudinal reinforcement and stirrup are bound, jumping binding is not allowed, and all shall be bound in place..
The fluctuation range of indentation diameter shall be controlled within the allowable fluctuation range determined by the supplier, and special gauges shall be provided for inspection.
After the sampled specimens are intercepted on site, the reinforcement at the original joint position is allowed to be overlapped and connected with reinforcement of the same specification, Or the welding and mechanical connection methods shall be used to make up the joint.
2、 There are 37 common problems in reinforcement construction quality.
The number of core hoops at the junction of beam and column is insufficient.
During binding, the welding slag shall be knocked clean in advance before binding.
The ends of the reinforcement shall not have local bending that affects the thread processing; The length of reinforcement wire head shall meet the design requirements, so that the tightened reinforcement wire heads shall not contact each other, and the machining length tolerance of wire head shall be – 0.5p ~ 1.5p; The taper and pitch of steel wire head shall be inspected with special taper thread gauge; The sampling quantity shall be 10%, and the inspection qualification rate shall not be less than 95%.
5.
The column cover does not meet the minimum cover thickness.
The construction of column reinforcement positioning hoop is not standardized, and the reinforcement is offset.
The specification of column stirrup and the height of densified area do not meet the drawing specifications, and the column stirrup is not bound, etc.
The length of the steel wire head shall meet the product design requirements in the enterprise standard, and the tolerance shall be 0 ~ 2.0P (P is the pitch): the steel wire head shall meet the accuracy requirements of grade 6F, and shall be inspected with a special straight thread gauge.
The threading personnel shall first test the number and length of the thread head of each specification, and the on-site operators shall screw it up and down evenly with thread pliers to ensure that one and a half threads are exposed at the top and bottom of the column straight thread connection.
Construction measures for column, wall, beam and slab reinforcement I.
The through gauge can be screwed in smoothly and meet the required screw in length, and the screw in of the non-stop gauge shall not exceed 3p.
The on-site inspection of reinforcement mechanical connection joint shall be carried out according to the acceptance batch.
4.
When installing the joint, the pipe wrench can be used to tighten it, and the steel wire heads shall be pressed against each other in the center of the sleeve.
6.
4.
If the tensile strength of one specimen still fails to meet the requirements in the re inspection, the acceptance batch shall be rated as unqualified.
The joint should avoid the stirrup densification area at the beam end and column end of the frame with seismic fortification requirements; When it is impossible to avoid, grade I joint or grade II joint shall be used, and the joint percentage shall not be greater than 50%.
No bending is set for the reinforcement outside the layer side column, and the bending is set for the straight anchor of the layer middle column.
2.
The standard values of the yield bearing capacity and tensile bearing capacity of the joint connector shall not be less than (1.10) times the standard values of the yield bearing capacity and tensile bearing capacity of the connected reinforcement.
The length of column longitudinal reinforcement is not staggered, and the exposed length does not meet the specification.
3.
14.
1、 Reinforcement connection mode the percentage of the cross-sectional area of the stressed reinforcement with joints in the same connection section to the total cross-sectional area of the stressed reinforcement (hereinafter referred to as the joint percentage) shall comply with the following provisions: 1.
7.
12.
For each acceptance batch of joints, 3 joint specimens must be intercepted in the engineering structure for tensile strength test, and evaluated according to the joint grade required by the design.
4.
When it is necessary to set joints at the parts with high stress, The joint percentage of grade III joints in the same connection section shall not be greater than 25%; The percentage of grade II joints shall not be greater than 50%; The percentage of class I joints may be unlimited.
For the parts with small stress of tensile reinforcement or longitudinal compression reinforcement, the joint percentage may not be limited.
One layer 5cm away from the concrete forming surface, and another layer at the upper and middle parts.
The processing of the straight thread of the reinforcement shall comply with the following provisions: the end of the reinforcement shall be cut flat or upset and then added with rework thread, and the thick head of the pier shall not have transverse cracks perpendicular to the axis of the reinforcement; 8.
common problems in column reinforcement quality 1.
Prevention and control measures 1 The construction team leader shall improve his sense of responsibility, calculate how many stirrups should be set on this floor according to the floor height and Atlas requirements, and disclose to the workers to avoid the phenomenon of core hoops at the junction of beams and columns.
The minimum tightening torque value during the installation of straight thread joint 11.
5.
The on-site shift leader shall carry out construction according to the drawings, and the reinforcement proofing personnel shall proofread according to the drawings and atlas to ensure that the specifications of column reinforcement meet the drawings, the column section meets the drawings and the end meets the specifications of atlas.
The specification and spacing of column stirrups and the height of densified area shall be constructed according to the drawings and atlas.
When electroslag pressure welding is adopted for column reinforcement, pay attention to the deviation and cavity of welding package, and the alignment of upper and lower reinforcement to ensure the quality of flux and grasp the welding time.
The extruded sleeve shall not have cracks visible to the naked eye.
The wire leakage of straight thread connection is uneven, and the electroslag pressure welding is not full.
The end of the reinforcement shall be free of local bending, serious corrosion and attachments; The end of the reinforcement shall be clearly marked to check the insertion depth of the sleeve, and the distance between the end of the reinforcement and the center point of the sleeve length shall not exceed 10mm; The extrusion shall start from the center of the sleeve and squeeze successively to both ends.
9.
The exposed thread of standard joint after installation shall not exceed 2p.
15.
Under the same construction conditions, joints of the same grade, form and specification of the same batch of materials shall be inspected and accepted with (500) as an acceptance batch, and less than (500) shall also be used as an acceptance batch.
The core hoop at the junction of beam and column shall be constructed at 10cm.
7.
For structural members directly bearing dynamic load, the joint percentage shall not be greater than 50%.
3.
If electroslag pressure welding is not full, it shall be cut off and re welded in time.
For the acceptance batch of joints that fail to pass the sampling inspection, the construction party shall study with the design and other relevant parties and put forward the treatment scheme.
3.
When the one-time pass rate of the tensile strength test of 10 consecutive acceptance batches is 100%, the number of joints in the acceptance batch can be expanded by (1) times.
10.
5.
8.
