Steel bars: hot-rolled round, ribbed, cold-rolled ribbed, waste heat treatment, epoxy resin coating

-- Reinforcement construction technology

1. Inspect the anti-replacement ring of the yard

(1) The variety, specification and performance of the steel bars used in reinforced concrete structures shall meet the design requirements and the current national standards "Steel for Reinforced Concrete Part 1: Hot-rolled Round Steel Bars" GB/T1499.1-2017, "Steel for Reinforced Concrete Part 2: Hot-rolled Ribbed Steel Bars" GB/T1499.2-2018, "Waste Heat Treatment Steel Bars for Reinforced Concrete" GB13014-2013, "Cold-rolled Ribbed Steel Bars" GB/T13788-2017 and Epoxy resin coated steel bar" JG/T502-2016 and other regulations, and other special steel bars shall comply with the provisions of their corresponding product standards.

(2) The steel bar should be accepted in batches according to different steel grades, grades, grades, specifications and manufacturers, and can only be used after confirming that they are qualified.

(3) The steel bar should be protected from rust, pollution and deformation during transportation, storage and processing. When stored at the construction site, it should be stacked neatly according to different varieties, specifications, and batches, and should not be mixed, and should be set up with identification marks, and the storage time should not exceed 6 months;

(4) The grade, type and diameter of the steel bar should be adopted according to the design requirements. When it is necessary to replace it, the original design unit should make a change in design.

(5) The lifting ring of the prefabricated component must be made of hot-rolled round steel bars that have not been cold-drawn, and shall not be replaced by other steel bars, and the calculated tensile stress when used shall not be greater than 65MPa.

(6) Before pouring concrete, the concealed engineering acceptance of the reinforcement should be carried out to confirm that it meets the design requirements and form a record

2. Straight down the bend end end prevention/excellent machine cold tensile rate, under the check of ingredients, the shape ruler scar hanging, room temperature once in the middle end, fouling flat diameter bend.

(1) The steel bar should be straightened before bending. When the cold drawing method is used for straightening, the cold drawing rate of HPB300 steel bar is not more than 2%; The cold drawing rate of HRB400 steel bar should not be more than 1%.

(2) Before the steel bar is cut, the variety, specification, grade and processing quantity of the steel bar should be checked, and the material should be batched according to the design requirements and the length of the steel bar. The steel bar should be cut and processed in a special workshop with numerical control machinery and equipment, and its shape and size should conform to the provisions of the design; After blanking, it should be listed and marked according to the type and use parts.

(3) The bending of the stressed steel bar and the end hook shall meet the design requirements or specifications.

(4) The form of the hook at the end of the stirrups should meet the design requirements or specifications. The bending diameter of the stirrup hook should be greater than the diameter of the main reinforcement of the stirrups, and HPB300 shall not be less than 2.5 times of the stirrup diameter, and HRB400 shall not be less than 5 times of the stirrup diameter; the length of the straight part of the hook shall not be less than 5 times the diameter of the stirrup in general, and the structure with seismic requirements shall not be less than 10 times the diameter of the stirrups.

(5) The steel bar should be bent at room temperature and should not be heated. The steel bar should be bent gradually to both ends from the middle, and the hook should be bent at one time.

(6) In the process of steel bar processing, measures should be taken to prevent oil stains, mud and other substances from pollution and prevent damage.

3. Welding machinery binding connection, flash resistance buried electric welding.

The hot-rolled steel bar joint should meet the design requirements. When the design is not required, the following provisions shall be met:

(1) Welded joints or mechanical joints should be used for steel joints.

(2) Flash butt welding should be preferentially selected for welded joints. The welded joints shall comply with the relevant provisions of the current national standard "Steel Welding and Acceptance Regulations" JGJ18-2012.

(3) The scope of application, process requirements, sleeve materials and quality requirements of mechanical connection joints shall comply with the relevant provisions of the current industry standard "Technical Regulations for Mechanical Connection of Steel Bars" JGJ 107-2016. The sleeve for rebar connection shall comply with the relevant provisions of the current industry standard "Sleeve for Mechanical Connection of Reinforcing Steel" JG/T163-2013.

(4) When the diameter of the steel bar in ordinary concrete is equal to or less than 22mm, when there is no welding condition, the binding connection can be used, but the main steel bar in the tension member shall not be connected by lashing.

(5) Resistance spot welding should be used for the intersection welding of the steel skeleton and the steel mesh sheet.

(6) For the T-shaped connection between the steel bar and the steel plate, submerged arc pressure welding or arc welding should be used.

4. The distance between the small areas is small, the grade end is not clear, the length of the tight core is checked, and the type of factory-level regulation.

The setting of rebar joints shall comply with the following provisions:

(1) There should be fewer joints on the same steel bar.

(2) The reinforcement joint should be located in the section with less force, and should not be located at the maximum bending moment of the component.

(3) In any section of the length of the welded or lashed joint, there shall be no two joints of the same steel bar, and the cross-sectional area of the joint of the stressed steel bar in the section shall comply with the provisions of the code.

(4) The distance from the end of the joint to the starting point of the steel bar bend shall not be less than 10 times the diameter of the steel bar.

(5) If the steel bar is not able to distinguish between tension and compression under the force during construction, it shall be treated according to tension.

(6) The transverse net distance of the rebar joint shall not be less than the diameter of the rebar and shall not be less than 25mm.

(7) Reinforcement mechanical connection joint - in the concrete structure, the part that requires full play of the strength of the reinforcement or the high ductility requirement should be selected grade II or grade I joint; when the percentage of reinforcement joint area in the same connection section is 100%, grade I joint should be selected.

(8) When the straight thread steel bar head is processed, the end of the steel bar should be cut flat by a band saw, a grinding wheel saw or a special steel bar cutting machine with an arc blade; the upsetting head should not have a transverse crack perpendicular to the axis of the steel bar; the length of the steel bar wire head should meet the product design requirements, and the limit deviation should be 0~2.0p; the steel bar wire head should be tested by a special straight thread gauge, and the general gauge should be able to be screwed in smoothly and reach the required screwing length, and the stop gauge screwing in should not exceed 3p. The number of self-inspections of each specification should not be less than 10%, and the inspection pass rate should not be less than 95%.

(9) When the straight thread joint is installed, it can be tightened with a pipe wrench wrench, and the steel bar wire head should be tightened against each other in the center of the sleeve, and the single-sided exposed thread after the installation of the standard, positive and negative wire type and reducer joint should not exceed 2p;

(10) After the straight thread joint is calibrated and installed, the tightening torque is checked with a torque wrench, and the torque wrench used for verification is checked once a year.

(11) The on-site sampling inspection items of straight thread joints shall include ultimate tensile strength test, processing and installation quality inspection. Sampling inspection should be carried out according to the acceptance batch, the same steel production plant, the same strength grade, the same specification, the same type and the same type of joint should be inspected and accepted with 500 as an acceptance batch, less than 500 should also be used as an acceptance batch.

5. The lofting card is tightly installed, and the ribs are connected with different lengths.

The fabrication and assembly of the steel skeleton shall comply with the following provisions:

(1) The welding of the steel skeleton should be carried out on a solid workbench.

(2) When assembling, the sample should be enlarged according to the design drawings, and the precamber of the skeleton should be considered when lofting. The precamber of the steel skeleton of the simply supported beam shall comply with the design and specification.

(3) When assembling, a wedge clamp should be used to clamp at the position that needs to be welded to prevent local deformation during welding.

(4) When the skeleton is welded, the center line of the steel bars of different diameters should be on the same plane.

6. One-way bilateral welding distance increases

The use of resistance spot welding of steel mesh shall comply with the following provisions:

(1) When the stressed steel bar of the welded mesh is HPB300 steel bar, if the welded mesh is stressed in only one direction, all the intersections of the stressed main reinforcement and the two transverse steel bars at both ends must be welded;

(2) When the stressed steel bar of the welded mesh is cold-drawn low carbon steel wire, and the spacing of the steel bar in the other direction is less than 100mm, in addition to the stress of the main reinforcement and all the intersections of the two transverse steel bars at both ends must be welded, the welding joint distance of the middle part can be increased to 250mm.

7、绑丝网架竖角向，箍筋垂螺叠位错

On-site binding of steel bars shall comply with the following provisions:

(1) The intersection of the steel bar should be tied with a binding wire, and it can be supplemented by spot welding if necessary.

(2) The intersection points of the two rows of steel bars on the periphery of the reinforcement mesh should be all firmly established, and the intersection points of the middle part can be staggered and fastened at intervals, but the reinforcement mesh and the steel bar intersection points of the two-way stressed reinforcement mesh must all be firmly rooted.

(3) The stirrups of beams and columns, except for special requirements in the design, should be set perpendicular to the stressed steel bars; the superimposed hooks of the stirrups should be located at the stressed steel bars of the beam and column angles, and be staggered (except for large cross-section beams and columns with more than two stirrups on the same section); the starting and ending points of the spiral stirrups should be tied to the longitudinal reinforcement, and the spiral stirrups with torsional resistance requirements should be extended into the core concrete.

(4) The angle between the hook plane of the vertical reinforcement at the corner of the rectangular column and the template surface should be 45°, the hook plane of the vertical reinforcement at the corner of the polygonal column should be towards the center of the section, and the hook plane of all vertical reinforcement reinforcement at the corner of the circular column should be towards the center of the circle. When the plug-in vibrator is used for small cross-section columns, the angle between the hook plane and the template surface shall not be less than 15°.

(5) The stirrup spacing within the lap length of the lashing joint: when the steel bar is in tension, it should be less than 5d and not more than 100mm, and when the steel bar is compressed, it should be less than 10d and not more than 200mm.

(6) Between the multi-layer steel bars of the steel skeleton, short steel bar pads should be applied to ensure the accurate position.

8. General pre-tensioning, machine connection reinforcement mesh, cushion block solidity

The thickness of the concrete cover of the reinforcement must meet the design requirements. When the design is not required, the following provisions shall be met:

(1) The minimum thickness of the concrete protective layer of ordinary steel bars and prestressed linear steel bars shall not be less than the nominal diameter of the steel bars, and the prestressed linear steel bars of post-tensioning components shall not be less than 1/2 of the diameter of their pipes.

(2) When the thickness of the concrete protective layer of the main reinforcement in the tension zone is greater than 50mm, a steel mesh with a diameter of not less than 6mm and a spacing of not more than 100mm should be set in the protective layer.

(3) The minimum thickness of the protective layer of the mechanical connector of the reinforcement shall not be less than 20mm.

(4) A cushion block should be set between the reinforcement and the formwork to ensure the thickness of the concrete protective layer of the reinforcement, and the cushion block should be firmly tied with the reinforcement and staggered. The concrete cushion block should have a strength not lower than that of the concrete of the structural body, and should have sufficient compactness.

(5) Before pouring concrete, the position, quantity and fastening degree of cushion blocks should be checked.

Yesterday 速记口诀

1. Design and verification of templates, brackets and arches

The knot is rigid and stable, the pre-arching force of the load, the rod base is set with a symbol, and the rigidity is checked and the anti-tilt is checked

2. Construction design basis

Knot across the load place to prepare

3. Construction design content

The general situation is based on the book materials, and the safety system is required to be dismantled

4. Load combination when designing templates, brackets and arches

12 self-weight, 5 side pressure, 3 walks, 4 vibrations, 6 tilting, wind and snow heat preservation 7 water, rigid and strong static movement.

5. The deformation value of the formwork, bracket and arch

Lu Lu 4 Bai Yin 25, 500 hoops 1.5.

6. The construction precamber of the formwork, bracket and arch should be considered

Bullet non-bullet pre-sinking

7. Production and installation of brackets and arches

The pressure base is forbidden to bubble and frozen, the column is in the middle of the hole, the support is not altogether, and the pressure frame is inspected in multiple layers.

8. Template production and installation

Cooperate with the pier platform tilt and check the special argument

9. Regulations on the installation of inflatable capsule core molds

When checking for leaks and stabilizing voltage

10. Provisions for the removal of formwork, brackets and arches

非不损，承加重，芯内不塌缝。

11. Regulations on the unloading of the arch of the mortar masonry and concrete block arch bridge

Pulp 80, small finish, solid arch protection, large empty arch horizontal

12. The principle of circular dismantling of formwork, bracket and arch

Split longitudinal and horizontal

Three days ago, shorthand mantra 4/6

1. Micro-surface processing process

Milk Modification Loading / Feeding

2. Applicable conditions for micro-surface treatment process

The strength of the structure is fully undamaged

3. Micro-table processing technology function

Water sealing, anti-slip and wear-resistant

4. Basic requirements for the construction of micro-meter processing projects

Digging and irrigation

5. Construction process and requirements of micro-meter processing project

Try to remove the moisturizing spray and flatten the culture

6. The treatment of the old asphalt pavement by the asphalt mixture surface layer

Strong damage is compensated at the same level

7. The treatment of the old cement concrete pavement by the asphalt mixture surface layer

Investigate fill-in-the-blank ticks

8. Preventive measures for horizontal deformation and reflection cracks of the old cement surface layer

Stress Reduction Layer

9. Preventive measures for vertical deformation and damage of the old cement surface layer

The bureau is broken and repaired, and the seam paste is filled

10. Treatment of the base of the old cement surface layer

Local crack replacement fill-in grouting

11. Treatment of cement concrete pavement disease

Broken and misaligned

12. The cement concrete pavement is paved with asphalt concrete surface layer

The elevation of the tube well position, the junction of the interring energy, and the soft place of the oil sprinkler

Seven days ago, shorthand mantra 4/2

1. The function and function of geosynthetics

Reinforced protective filter drainage

2. Material properties and purpose of embankment reinforcement

Pull grip to tear the roof to improve the stability of the embankment

3. Construction of reinforced embankment

The principle is to connect the table and fill the unloading slope

4. The subgrade of the back of the platform is filled with soil and reinforced

The purpose is to highly strengthen the mold filling, and avoid the longitudinal overlap pressure between the connections

5. The construction procedure of filling and reinforcing the subgrade of the platform

Clear the table pressure base anchor, spread the positioning points

6. Pavement crack prevention materials and requirements

The glass fiber fabric has strong negative elongation, and the mesh size is simple and resistant to high temperature

7. Pavement crack prevention and control construction

Outside the evaluation of the old road oil and soil

8. Roadbed protection

123 slope, float slippery thick curved float

9. Basic requirements for the construction of geosynthetics

The regulations are old and dirty, and the anchors are wrong and flat

10. Construction quality data of geosynthetics

Concealed log strong side station

Two weeks agoShorthand mantra 3/26

1. Basic classification of asphalt mixture

Granularity

2. Asphalt mixture structure type

Crowded

3. The mechanical strength of asphalt mixture

Friction sticky

4. The structure of asphalt mixture composed according to the principle of grading

The overhang skeleton is empty

5. Characteristics of suspension-dense structure asphalt mixture

Large sticky angle before subcharge

6. Characteristics of skeleton-void structure asphalt mixture

The thickness is more and the thickness is less, and the sticky low angle is high

7. Characteristics of skeleton-dense structure asphalt mixture

The thickness of the break is fine, the rubbing is high

8. The difference between the main types of hot mix asphalt mixture

Group special