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Standardization of bridge substructure construction process (I) requirements for standardization of bridge common foundation construction 1.
② common problems of reinforcement cage processing site: standardized construction requirements: reinforcement cage processing shall be made on the hardened site with cement pedestal.
The spacing between precast pedestal and beam storage pedestal shall be greater than twice the width of formwork.
when the diameter of reinforcement is greater than or equal to 25mm, mechanical connection should be adopted, and sheath protection should be added after the wire head passes the inspection.
Common problems of standardized steel formwork: standardized construction requirements: the core formwork of precast box girder and hollow slab girder shall use shaped steel formwork, which shall meet the relevant requirements of “formwork access system”, and shall be reported to the director’s office for inspection and acceptance.
positioning of top and side reinforcement: the top and side are fixed with reinforcement, and the positioning tie bar is pulled outside the formwork with a wire tensioner.
Common problems in reinforcement positioning of prefabrication beam: standardized construction requirements: ① special jig frame for reinforcement,) reinforcement should be installed by binding and forming on the special jig frame, and then lifting as a whole.
The opening shall be covered with fences and warning signs, and the opening shall be 30cm higher than the ground.
③ common problems of mud pit: standardized construction requirements: the average value of mud index sampled from the top, middle and bottom of hole pile after hole cleaning; The perimeter shall be enclosed.
Problems of dug cast-in-place pile: standardized construction requirements: there shall be sufficient lighting, ventilation and exhaust facilities in the hole of dug cast-in-place pile, and an escape ladder shall be provided at the same time.
② reinforcement positioning # A.
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（3） Requirements for standardization of reinforcement processing common problems: requirements for standardized construction: 1.
Common problems of diaphragm bottom formwork: (II) standardized construction requirements for beam prefabrication: in order to ensure that the diaphragm bottom formwork can still play a supporting role after the side formwork is removed, the diaphragm must adopt an independent steel plate bottom formwork, which can be removed after tensioning construction.
After placing, the reinforcement cage shall be prevented from sinking or floating.
What is “standard”? It is a normative document that formulates common and reusable rules for actual or potential problems in order to obtain the best order within a certain range.
Common problems of foundation expansion: standard construction requirements: the base is 0.5-1m wider than the plane size of the foundation, the bearing capacity and geological conditions of the base meet the design requirements, and geotechnical test shall be carried out.
Standardized construction requirements: full length steel plates should be used for the pedestal bottom formwork.
After using the reinforcement positioning frame, the installation is accurate and the framework is firm and neat.
Common problems in abutment construction: standardized construction requirements: ① abutment formwork generally adopts large steel formwork or large bamboo plywood.
After the commencement of each bridge, after the completion of the first finished or semi-finished products such as pile foundation, pier column and beam, the director’s office shall organize the construction unit to analyze the quality status and process details and form a formal report before mass construction.
For bridges with longitudinal slopes, triangular wedges should be set at the supports at both ends of the pedestal to ensure the levelness of the supports.
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（2） Standardization requirements for bridge pier and abutment construction 1.
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Intelligent} promote intelligent CNC reinforcement processing machinery to reduce labor intensity and improve manufacturing quality and production efficiency.
B.
the cushion blocks for the protective layer of the reinforcement cage shall be round cake cushion blocks, the longitudinal spacing shall not be greater than 2m, and each track shall be set symmetrically along the circumference, and there shall be no less than 4 blocks.
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Common problems of Prefabrication Yard hardening and drainage setting: standardized site requirements: the site shall be hardened with concrete above C15.
④ analysis of common reinforcement binding problems and standardized construction requirements: according to the specifications, the end of the stirrup shall be made into a hook, and the hook angle can be 135 °.
Pier construction ① the formwork installation of pier and bent cap meets the allowable deviation, and the lifting of bucket shall be commanded by a specially assigned person.
The prepared reinforcement skeleton must be placed flat and shall be made with standardized molds.
② after the formwork is removed, the column shall be wrapped with plastic film immediately, and the pier top drip irrigation and other methods shall be adopted for curing.
③ Common problems of diaphragm reinforcement positioning: standardized construction requirements: triangular support positioning frame is adopted.
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T-beam reinforcement positioning: rib plate reinforcement binding shall be carried out by fetal membrane, which shall be hung on the pedestal as a whole after installation.
· the reinforcement processing yard shall be scientifically and reasonably set up according to the raw material stacking area, reinforcement blanking area, processing and manufacturing area, finished product stacking area, semi-finished product stacking area and waste area, with clear functions and marks.
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The standardization of bridge construction process mainly requires key requirements: first, pay attention to the access of formwork, and unqualified formwork is not allowed to be used in production to ensure the appearance quality of concrete; Second, pay attention to the control of beam and slab prefabrication process to ensure the concrete strength, the thickness of reinforcement protective layer and the thickness and flatness of bridge deck pavement; Third, pay close attention to the “first piece analysis system”.
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Standardization of bridge superstructure construction process (I) standardized construction requirements of Prefabrication Yard 1.
The hardening thickness shall not be less than 10cm, and the thickness as a carriageway shall not be less than 15cm.
Pier cage and torsion cage are strictly prohibited.
Setting of rainproof shed ， the reinforcement processing yard shall be provided with roof rainproof facilities, which should be set up with steel structure, lightning protection and wind protection facilities, and the outdoor temporary reinforcement stacking place shall be provided with mobile ceiling for covering.
④ common problems of reinforcement cage placement: ⑤ reinforcement cage placement: the placement shall be aligned with the hole position, stable, slow and straight, so as to avoid collision with the hole wall.
B.
② formwork reinforcement and support: the removal of formwork and support shall be supported first and then removed, and the latter shall be removed first.
The position of structural reinforcement should be accurately marked on the jig frame, so as to effectively ensure the accuracy of reinforcement installation position and avoid the loss of reinforcement.
Bridge bored pile foundation ＾ ① fabrication of reinforcement cage ＾ common problems: the main reinforcement joint of reinforcement cage is set incorrectly, with a diameter of 25mm, which shall be mechanically connected with reinforcement instead of double-sided welding; And the cushion block of reinforcement protective layer is not used.
（4） Prefabrication beam construction process requirements 1.
The length of the straight section of the hook shall not be less than 5 times of the diameter of the stirrup in general structure and 10 times of the diameter of the stirrup in seismic structure..
Standardized construction requirements: A.
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