1 General
1.0.1 In order to meet the needs of the construction of cross-sea steel box girder bridges and to ensure the safety and quality of the factory manufacture, transport and installation of large sections of steel box girders, these regulations are established.
1.0.2 These regulations apply to the construction of large sections of cross-sea steel box girder bridges.
1.0.3 The construction of large sections of steel box girder shall comply with the design documents and shall meet the requirements of safety, durability, environmental protection and green low carbon.
1.0.4 The construction of large sections of steel box girder should be standardised, standardised, assembled and digitalised, and the use of reliable new materials, equipment, technology and techniques should be actively promoted.
1.0.5 The construction of large sections of steel box girders shall establish a special safety and quality management system in accordance with current laws and regulations to ensure the occupational health of construction personnel and to guarantee construction safety and quality.
1.0.6 The construction of large sections of steel box girders shall conform to the provisions of these regulations, in addition to the provisions of the relevant national and industry standards.
2 Terminology
2.0.1 steel box girder large-section large-segmentsteelboxgirder
A steel box sorghum of not less than 50m in length assembled from two or more designed small sections!
2.0.2 temperatureeffect
The effect of the temperature difference between the actual temperature of the steel box girder and the design reference temperature during construction on the state of the steel box girder and the stress state.
2.0.3 Bearing pre-deflection bearingoffsetting
To offset the temperature difference between the construction temperature and the design reference temperature and the subsequent construction etc. of the bearing slip, the process of setting the upper bearing plate relative to the lower bearing plate in reverse offset before the bearing is installed.
2.0.4 Beam steelboxgirderadjusting
The process of adjusting the plane position and elevation of a large section of a steel box girder after it has been lifted and before it is joined at the ring joint.
2.0.5 Steelboxgirderlocating
The process of converting a steel box girder from a temporary bearing support to a permanent bearing support.
2.0.6 Largesegmentsassembling
The process of assembling small sections of a steel box girder into large sections in the factory prior to installation to ensure the accuracy of the manufacture and installation of the large sections of the steel box girder.
3 Basic provisions
3.0.1 The construction of large sections of steel box girder shall be divided into factory fabrication, transportation and bridge installation. The construction organisation design and special construction programme shall be prepared before construction and shall be coordinated with the special construction programme for each component project.
Article description
The bridge installation generally includes bridge lifting, bridge connection and supporting system transfer operation and other processes. The preparation of special construction plan should meet the requirements of quality, safety, schedule, cost plutonium and civilized construction in the construction organization design, and consider the factors and requirements of construction method selection, construction process flow, risk identification and countermeasures, emergency plan, etc., and coordinate with the relevant sub-project special construction plan, etc.
3.0.2 The construction of large sections of steel box girders shall be subject to a first work approval system.
Article Description
The construction of the first section normally requires verification of the workmanship standards, resource allocation, work efficiency, safety and quality of the construction of the world, transport and bridge installation, etc. / standardisation of work procedures.
3.0.3 The construction of the steel box girder scorched back section shall be subject to special design and calculation of temporary facilities such as supporting structures and spreader structures, and shall be verified by test loading if necessary.
3.0.4 The use of advanced processes and equipment such as automated assembly, welding and painting robots, large crane vessels, etc. is desirable for the manufacture and installation of large sections of steel box girders.
4 Factory fabrication
4.1 General provisions
4.1.1 Large sections of steel box girders shall be manufactured in the factory in stages according to the process of plate unit fabrication, small section assembly and total assembly of friendly sections.
Article Description
The general process flow for the factory fabrication of large sections of steel box girder is generally. Steel pole treatment → material → plate unit fabrication → small section assembly → small section rust removal and painting → large section general painting → large section storage. If the conditions allow, it is also possible to carry out painting after the total assembly of large sections directly.
4.1.2 The manufacturing unit shall use three-dimensional modelling technology to review the structural structure and manufacturing process, and may consider using a solid model for verification if necessary.
Article description
A three-dimensional visualisation model of the heart is usually used to review the construction and process of complex situations such as the section intersection surface and the bearing plate in place on the steel box girder support
4.1.3 Plate units shall be fabricated using a precision cutting process with strict control of welding distortion.
Article description
In order to ensure the accuracy and quality of the plate unit production, the plate unit production is usually considered to use high-precision CNC cutting machine for undercutting, multi-head portal welding machine. and anti-distortion ship position welding process for welding.
4.1.4 Small section grouping should be manufactured using the long line method of matching, and it is advisable to use the technique of grouping without process plates or with fewer process plates, and effective measures should be taken to control welding deformation.
5 Transport
5.1 General provisions
5.1.1 Sea transport shall be selected according to the transport area, transport distance, meteorological and hydrological conditions, steel box girder structure, existing equipment and other conditions, and the transport mode of transport shall be separated or integrated.
5.1.2 Special schemes and operational details shall be prepared for loading the vessel and shall be selected under sea conditions suitable for safe operation of the vessel.
5.1.3 Marine transportation shall be discussed and planned in advance in conjunction with the sea conditions, and a special programme shall be prepared and submitted to the maritime authorities for approval before implementation. The transport process shall be the responsibility of a person, and shall comply with the rules and regulations of the sea collision and shipping, and take effective measures to prevent navigation safety accidents.
5.1.4 A packing list, a certificate of conformity confirmed by the steel beam manufacturer and the supervising engineer shall be prepared before shipment.
Article Description
The fabrication and installation of large sections of steel box girders often belong to different units and the transport link is the interface between the different units. In order to ensure an orderly handover, the product certificate accompanying the beam shipment includes (not limited to) the name and number of the steel box girder section, the date of shipment, the mass and geometry of the steel box girder section, the measured manufacturing line, temporary construction equipment, etc.
5.2 Separate transport
5.2.1 Shipment shall be in accordance with the following provisions:
1 The ship loading scheme shall take into account the structural characteristics, quay conditions, in-plant transfer mode and ship loading equipment and other factors to determine, and may adopt such schemes as lifting on board or rolling on board.
2 When using the crane on board scheme, the lifting system shall be tested according to the requirements, and the spreader and connecting device shall be inspected and qualified before being used for lifting large sections of steel box girder.
3 When using the roll-on/roll-off solution, the stability of the transport vessel shall be controlled during the loading process.
6 Bridge lifting
6.1 - General provisions
6.1.1 A site survey shall be carried out before the lifting of large sections of steel box girder to ensure that the lifting meets the requirements of the aviation height limit and water depth, and that dredging shall be carried out if the water depth is insufficient.
6.1.2 The relative position of the lifting vessel and the transport vessel under each process shall be planned before the lifting of large sections of steel box girder, and a unified command scheme shall be formulated and a person shall be responsible for the command.
6.1.3 The spreader system for large sections of steel box girder shall be specially designed according to parameters such as the form of the lifting vessel knot tree and the geometry of the steel box girder.
6.1.4 A lifting exercise shall be carried out before the formal lifting of large sections of steel box girder
6.1.5 Large sections of steel box girder that are transported in a separate carrier shall be subjected to a test hoist prior to formal lifting.
Article Description
A counterweight is normally set on the large section of steel box girder to be lifted, the total weight of the test lift is not less than 1.1 times the weight of the girder, more pressure and less lifting is used to carry out the test neighbourhood, and the steel box girder is kept clear of the transport vessel during the test lift.
6.1.6 The lifting of large sections of steel box girder shall be carried out under sea conditions and meteorological conditions suitable for safe operation of vessels with winds below force 6. Lifting operations shall be carried out during daylight hours when visibility is good and night lighting facilities shall be prepared.
Article description
There are many factors affecting the lifting of large sections of steel box girders, and there may be complicated and unexpected situations where lifting operations may continue into the night.
6.1.7 Under the premise of ensuring the overall and local stress safety of the steel box girder, the spreader can be rested on the steel box girder after lifting, but the local stress and alignment change of the steel box girder should be assessed, and the surface of the girder should not be polluted and damaged. A special spreader storage platform should be set up when available.
7 Bridge connection
8 Conversion of support system
9 Installation quality control
1 General
2 Terminology
3 Basic provisions
4 Factory fabrication
5 Transport
6 Bridge lifting
7 Bridge connection
8 Conversion of support system
9 Installation quality control
