Big hexagonal high-strength bolt connection

1 scope

This technology is applicable to steel structure installation engineering, construction technology of big hexagonal high-strength bolt connections.

2 construction preparation

2.1 materials:

2.1.1 bolts, nuts, washers should be accompanied by certificates of quality and provisions should comply with the design requirements and national standards;

2.1.2 high strength large Hexagon head bolt specs, dimensions and weights shall conform to table 5-4 requirement.

2.1.3 large Hexagon nuts with high specifications, dimensions and weights shall conform to table 5-5 requirement.

2.1.4 high strength plain washers for specifications, dimensions and weights shall conform to table 5-6 requirement.

2.1.5 different grades of the material properties of high strength large Hexagon head bolt table 5-7 requirements must be met.

2.1.6 different specifications of high strength bolts of mechanical properties, tensile force shall comply with table 5-8 requirement.

2.1.7 the hardness of high strength large Hexagon head bolts shall conform to table 5-9 requirement.

2.1.8 connections of high strength large Hexagon head bolt is a bolt, two washers and a nut, bolt, nut and washer should be supporting the use of table 5-10.

2.1.9 acceptance after storage of high strength large Hexagon head bolts should be kept classified according to specifications. Should be protected against rain, moisture, in case of thread damage or bolt and nut are not facilities shall not be used.

2.1.10 high strength large Hexagon head bolt storage time is too long, or when there is a rust should be sampled fastening axial forces, to meet the requirements before use. Bolts, sticky stained dirt, grease, and must be cleared.

2.2 the main tools:

Control boxes, electric torque wrenches and hand torque wrench, torque measurement of wrenches, hand wrenches, wire brushes, punches,

2.3 operating conditions:

2.3.1 high strength bolt friction surfaces must conform to the design requirements, the coefficient of friction must meet the design requirements. Friction surface residual iron oxide is not allowed.

2.3.2 conditions of friction surface processing and save time, save and friction coefficient test saves time, conditions are the same.

2.3.3 construction parts of the friction surfaces should be protected from oil and paint and other contamination, such as pollution must be thoroughly cleaned.

2.3.4 adjust torque wrench. According to the technical requirements, carefully adjusting the torque wrench. Torque Wrenches-torque value should be

Within the tolerance range. Torque wrench for construction, and the error should be controlled within ± 5%. Calibration of torque wrenches. The errors should be controlled within ± 3%.

2.3.4.1 construction when using electric wrench, applied when set his stall torque measuring wrench torque wrench repeatedly correction requests are consistent with the design. The torque value is too high, high strength bolts to twist, causing bolts overrun, as time is too long, will make cracking of high strength large Hexagon head bolts and other hidden dangers. When torque value is too low, the high strength bolt fastening not up to a predetermined value, resulting in decreased coefficient of friction between the connecting surface of steel structure, bearing capacity.

2.3.4.2 construction manual when every day should be manually detected by measuring the torque wrench wrench fastening position correctly, check that the displayed signal manual wrench is sensitive to prevent hyper-screwed or fastened in place.

2.3.5 check bolt hole of aperture, Kong Bianmao spines must be thoroughly cleaned.

2.3.6 the same number, size of bolts, nuts, washers with a good set, cased.

2.3.7 operators to cope with large Hexagon head bolts with high strength training or technical disclosure, which reads as follows:

2.3.7.1 large Hexagon head bolts with high strength characteristics and requirements.

2.3.7.2 friction coefficient and torque coefficient for high strength bolt.

2.3.7.3 high strength bolt fastening fastening points and principles.

2.3.7.4 high strength bolts for storage and transportation, storage and on-site construction requirements.

2.3.7.5 properties of high strength bolt torque wrench and method of use.

2.3.7.6 the performance of high-strength bolt wrench and method of use.

2.3.7.7 high strength bolt fastening after the self test self requirements and inspection methods, content.

3 operational processes

3.1 process:

Ready → connector Assembly → temporary → Setup → high-strength of high strength bolt bolt bolt →

Inspection and acceptance

3.2 job preparation:

3.2.1 ready wrench, temporary bolts, overshoot, brushes, and other tools, deals with construction of torque calibration, is used on the torque wrench must be corrected before the class, torque calibration must only be used after. Shall designate a person responsible for torque correction.

3.2.2 big six angle head high strength bolt length select, consider to steel component processing Shi used steel General are for are tolerance, sometimes material alternative and more is to big generation small, to thick generation thin mostly, so connection total thickness increased 3~4mm of phenomenon many, so, should select good high strength bolt length, General to tight solid Hou long out 2~3 buckle suitable, then according to requirements distribution good sets alternate.

3.3 connector Assembly:

3.3.1 the friction surface is clean, not straight, should be assembled in straight will be required. Friction surface must not have paint, mud, there should be no burrs around the holes should be treated with the friction surface cleaning with a wire brush, the brush should be perpendicular to the direction of friction.

3.3.2 when problems are encountered mounting holes, not use oxygen-acetylene reaming, hole drilling reaming, hole deburring holes around back after.

3.3.3 high strength bolted connection Panel tightly against real, due to thickness tolerances, manufacturing variations or installation errors, such as the contact gap, should be dealt with as provided for in table 5-11.

3.4 Installing temporary bolts:

3.4.1 temporary bolted steel components assembled should be installed first, temporary mounting bolt cannot use high strength bolt in place, the number of temporary mounting bolt hole in the connecting plate to General Group of 1/3 cannot be less than 2.

3.4.2 not being the little holes, displacement is small, you can use drift pin into position, then install bolts.

3.4.3 hole position on the Board is not correct, displacement is large reamer reaming.

3.4.4 movement the individual holes is larger, should weld again after punching.

3.4.5 no punches while putting on the correct holes into high strength bolts.

3.4.6 Installing bolt is 30%, you can tighten the mounting bolt location.

3.5 install high strength bolts:

3.5.1 high strength bolts should be free to wear inside the hole, forbidden forced high-strength bolts into the holes with a hammer.

3.5.2 high strength bolts into the direction should be consistent, except for local structural obstacles.

3.5.3 shall not be installed in a rainy high strength bolts.

3.5.4 high strength bolt washer location should be consistent, and washers for installation should pay attention to the positive and negative directions.

3.5.5 bore no shear high-strength bolts should be tightened.

3.6 high strength bolt fastening:

3.6.1 all high strength large Hexagon head bolts after installation, you can begin to fasten. Fastening method is divided into two steps, namely, twist at the beginning and the end twist. All the early high strength bolts should be screwed first screw Torque should be standard axial force 60%~80%, which also depends on the thickness, bolt spacing and the appropriate master. Plate thickness, bolt layout space is large, the axial force of twist at the beginning should be larger as well.

3.6.2 Screw tightening sequence at the beginning, according to high strength large Hexagon head bolt tightening sequence requirements, where general joint stiffness from the free end of the restraint order; or to diffuse from the bolt group Center direction. This is because the connection plate warpage when not in prison, such as from the ends to the Middle fastening, likely bolstered splice plates but not that close, thus losing some of the friction force.

3.6.3 early high strength large Hexagon head bolt tightening should be marked to prevent leaking screw. After screw marked with a color at the beginning, one end of the twist with a color, a distinction. Figure 5-1, is mixing early high strength bolt final twisting by tag.

3.6.4 in prevention of high strength bolt under the influence of external environment, bring about changes in the torque coefficient, usually beginning to twist, twist should be completed within the same day.

3.6.5 any structure, individual high strength large Hexagon head bolt into the direction cannot be consistent, when tightening bolts, only on the nut torque, no torque on the screw to prevent the torque coefficient changes.

3.7 high strength large Hexagon head bolt check

3.7.1 construction operation to check in. Checks whether the construction technology in the construction according to the requirements of construction technology, specific contents to check the following items:

3.7.1.1 temporary bolts to install, the provisional number of bolts above 1/3.

3.7.1.2 is free to enter into high strength bolts, hammer forcibly is strictly prohibited to enter.

3.7.1.3 high strength bolt fastening in the correct order or not, fastening method is correct.

3.7.1.4 sampling for the determination of torque wrench torque values, allowable design range.

3.7.1.5 check connection plate cleaning, ensure the reliable quality of friction surfaces.

3.7.2 quality inspection of high strength large Hexagon head bolts.

3.7.2.1 in 0.3kg the hammer method, Census of high-strength bolt to prevent leaking screw.

3.7.2.2 torque check, check the bolts for each node in 10%. But not less than one. Check on the bolt and nut end surface before painting a straight line, and then leave the nuts loose for about 60 °, using a torque wrench to tighten again, two line, measuring of torque should be 0.9Tch~1.1Tch to qualify.

Tch calculated according to the following formula:

Tch=K×P×d

Tch--check the torque (N • m);

K--torque coefficient;

P--strength bolt design pretension;

D--of high strength bolt diameter.

If irregularities are found, should be expanded to check 10%, if there are failed, the entire node high-strength bolts should be tightened again.

Should be during bolt final twisting by torque check after 1h, 24h finish.

3.7.2.3 with feeler gauges check the gap between the connecting plates, when the gap exceeds 1mm, must be reprocessed.

3.7.2.4 check high strength large Hexagon head bolt into the consistency of direction, check whether the gasket correctly.

4 quality criteria

4.1 project:

4.1.1 high strength large Hexagon head bolts specification and technical conditions should comply with the design requirements and existing national standards of the high strength large Hexagon head for steel bolt, hexagon nut, washer technical provisions of the conditions.

Test method:-by-lot inspection quality certificates and inspection reports.

Content has high strength large Hexagon head bolt, nut, gasket material properties grade GB 3,633,183 requirements must be met.

4.1.2 anti-slip coefficient of high strength bolt surface. Must meet the design requirements.

Test method: check the anti-slip coefficient of component processing unit test reports, inspection re-inspection report of anti-slip coefficient at construction site. Construction site and steel components of friction surface of the specimen at the same time, save under the same environmental conditions, in order to ensure reliable experimental data. Specimen friction coefficient do three sets, taking the average.

4.1.3 high strength large Hexagon head bolt torque coefficient should be carried out re-inspection, the results should be consistent with existing national standards for the high strength large Hexagon head for steel bolt, hexagon nut, washer technical provisions of the conditions.

Inspection method: check the torque coefficient re-inspection report to reinspect the bolts should be installed at the construction site for the bolt group of randomly, each batch of samples taken 8 connections for re-inspection.

4.1.4 friction surface of high strength large Hexagon head bolt surface should be flat and without Burr, Burr, welding spatter, weld scar, iron oxide scale, dirt and does not need coating.

Inspection method: Visual check.

4.1.5 tighten high strength large Hexagon head bolts with the torque wrench should be calibrated on a regular basis, early bolt screwed in accordance with existing national standards for the engineering code for construction and acceptance of steel structure (GB50205-95) requirements, the final twisting can be carried out.

Test, check the torque wrench calibration and bolt construction records.

4.1.6 high strength large Hexagon head bolts should be free to wear into the bolt holes should not force to beat.

Inspection method: Visual check.

4.2 Basic project:

4.2.1 high strength large Hexagon head fitted bolts for joints of exterior quality:

Qualified bolt into the directions are basically the same, exposure should be no less than 2 buttons.

Excellent bolts into the same direction, the exposed length should not be less than 2 buttons, with long evenly.

Check amount: according to the number of spot checks 5%, but not less than 10 nodes.

Inspection method: Visual check.

4.2.2 torque construction of high strength large Hexagon head bolt final twisting by quality:

Qualifying: bolt final twisting by torque screw or a bolt was replaced early by the inspection, in line with the current standards of the code for construction and acceptance of steel structure (GB 50205-95) regulations.

Excellent: bolt final twisting by torque with a check that is to meet the national standard (GB50205-95) requirements.

Check amount: according to the number of spot checks 10%, but should not be less than 10 nodes each selected node according to the number of bolts check 10%, but should not be less than 2.

When final twisting by torque when you do not meet the existing standards, and sample checks on the nodes of bolts for 20% should be expanded, when unqualified, the node should be bolt all the checks when there are unqualified, 20% of random node should be expanded when there are unqualified, all nodes should be subject to checks.

5 finished product protection

5.1 has high strength large Hexagon head bolt final twisting should be well marked.

5.2 has been mixing nodes and friction surfaces should be kept clean and tidy to prevent oil, dust pollution.

5.3 has mixed node should avoid excessive local impacts and oxy-acetylene baking.

6 quality problems to be noticed

6.1 construction of high strength bolt's installation should be avoided in snow and rain, so as not to affect the quality of construction.

6.2 high strength large Hexagon head bolts should be used the same day brought out from the warehouse the same day, how best how much day unused high-strength bolts cannot be piled up in the open air and should be returned to the Treasury, for use the next day.

6.3 if expansion is required during the installation process of high strength bolt holes, be sure to pay attention to prevent metal debris trapped between the friction surfaces must be clean before installing.

7 quality records

This standard shall meet the following quality records:

7.1 high strength large Hexagon head bolts factory certificate.

7.2 high strength large Hexagon head bolts to reinspect the proof.

7.3 twist, at the beginning of the high strength bolt final twisting by torque values.

7.4 torque wrench for construction and inspection record.

7.5 the construction quality check and acceptance record.