The construction and supervision of channels, box culverts and slab culverts within the supervision scope of this supervision office shall meet the following requirements:
According to the engineering contract documents, the construction drawing design requirements of this section, the technical standards for highway engineering (JTJ00 1-97), the quality inspection and evaluation standards for highway engineering (JTJ07 1-98), the technical specifications for highway drainage design (JTJ0 18-96) and highway subgrade.
Second, the supervision of the construction preparation stage
(1) raw materials
1, cement:
(1) Cement from the same manufacturer must be used in the same small structure.
(2) The cement manufacturer has been confirmed by the owner and the supervision office, and the warranty information of the manufacturer is complete.
(3) Try to use canned cement (used for mixing concrete in the mixing building). When using bagged cement, the weight of each bag of cement must be randomly weighed. The warehouse should be waterproof and moisture-proof, and the drainage ditch should be unblocked. The ground of the warehouse should be emptied after treatment, and the stacking height should not exceed 10 bag, with linoleum on it, and the inventory should be above 100 ton.
(4) According to the entry date and batch number, the cement shall be neatly stacked, and the cement that is damp or stored for more than 3 months shall be re-sampled. If the re-inspection result is unqualified, it should be removed from the field.
(5) The fineness, mortar strength, stability and setting time of cement shall meet the requirements of GB- 175- 1999.
2. Gravel:
(1) Needle-shaped particles, silt content, clod content and crushing value should meet the specification requirements, and the project department must pass the self-inspection and can only use them after passing the sampling inspection by the supervision office.
(2) The site must be hardened and the surrounding drainage is good.
(3) a sign indicating the place of origin, specifications, quantity, place of use, and whether the inspection is qualified.
(4) Washing equipment must be provided, and the crushed stones with excessive silt content must be washed and qualified before entering the yard.
3. Huangsha:
(1) silt content, silt content and fineness modulus shall meet the specification requirements and design requirements, and shall be self-checked by the project department, and can only be used after passing the sampling inspection by the supervision team.
(2) The site must be smooth and hardened with good drainage around.
(3) The signboard shall indicate the origin, specification, quantity, use position and whether it has passed the inspection. When the content of particles larger than 5mm exceeds 10%, it must be screened before entering the yard.
4, steel bar:
(1) The steel bar manufacturer must be confirmed by the owner and the supervision office, and the steel bar quality assurance information is complete.
(2) Steel bars should be stacked in the warehouse, and the height should be raised when stacking, and the manufacturer, specification, model, use position and whether they have passed the sampling inspection should be clearly indicated on the sign.
(3) The mechanical performance test shall comply with GB 1499- 1998 and GB/70 1- 1997.
5, admixture:
(a) the main performance indicators should meet the requirements of GNB8076- 1997.
(2) Mix proportion
The theoretical strength of concrete mixture ratio should meet the design requirements and has been approved by the supervision engineer.
(3) Mechanical equipment
1, mixing, vibrating, steel processing machinery, generators and other mechanical properties should be good, meet the construction requirements, operate normally, and need to have spare machinery.
2. The hoisting machinery should match the weight of the hoisting machinery, which is safe and reliable.
(4) Site leveling
Remove the sundries in the site, ensure the smooth access roads and transport vehicles, and facilitate the construction.
(5) lofting and positioning
1, the pile location is reliable, the protection pile is firm, and the intersection angle is correct.
2. After the project department sets out, it shall be reported to the supervision department for retest before construction.
(6) Application for commencement of the project
The construction organization is sound, the responsibilities are clear (according to the organizational system, quality assurance system and safety system), the schedule is arranged to ensure the construction period, the process flow is clear, there is no omission, and it meets the specification requirements.
Third, supervision in the construction stage.
(1) basis
1, the elevation and plane size of the basement meet the design requirements.
2. The water level should be lower than the bottom of the foundation, and the foundation will not accumulate water or soak in water.
3. Replacement (if required by the design) The replacement construction shall conform to the requirements of the specification, and the width shall be left with sufficient margin. Pile diameter and pile spacing of composite foundation (if required by design) should not be less than design.
4. If the bearing capacity of foundation is inconsistent with the design drawings and fails to meet the requirements, it shall be reported in time, and relevant procedures shall be handled according to the prescribed procedures to apply for change.
(2) steel processing and installation
1. Straighten and remove rust, make it straight without local bending, and the surface is clean without oil stains and rust spots.
2, steel welding:
(1) Welders shall hold relevant certificates.
(2) covered electrode, flux should have the certificate of approval and meet the requirements.
(3) After the trial welding, the welding process and parameters have been approved by the supervision engineer.
(4) When lap welding is used for welded joints of steel bars, regardless of whether the axes are consistent, the weld length shall be no less than 10d for single-sided welding and 5d for double-sided welding, and the weld shall be full without welding slag.
(5) When butt welding is used for welded joints, there should be no cracks at the joints, and there should be no burns, undercut, cracks and flash on the surface of steel bars.
(6) The joint curvature shall not be greater than 4 degrees, and the axis deviation shall not be greater than 2mm.
(7) The main reinforcement in tension area shall not be bound, and the number of joints of main reinforcement in tension area within the same section shall not exceed 50%. The welded joint of the main reinforcement in the tension zone should avoid the maximum stress section.
3, steel skeleton:
(1) The skeleton length, diameter, specification, quantity, spacing, stirrup, point reinforcement position and protective layer thickness meet the design requirements.
(2) the protective layer pad is complete and reliable.
(3) model
1, and the dimensions of each part meet the design requirements.
2, bracket connection should be close, to ensure the stability and reliability of the bracket.
3, the template should be supported by internal bracing, fixed with screws, to prevent sinking, other support should be stable and firm.
4. The joints of the formwork must be tight, and the exposed joints should be handled well. The exposed surface of the channel must be large steel formwork or plastic plywood.
5. Expansion joint plates shall be fixed according to waterproof treatment, with correct position and firm fixation, consistent from top to bottom.
(4) Foundation concrete
1, the construction mixture ratio should be adjusted in time according to the actual water content of sand and gravel.
2, check whether the concrete slump meets the requirements.
3, making sampling concrete block.
4, mixture measurement is reliable and accurate.
5, expansion joint size, location, correct and firm.
6. The construction site should be civilized and safe.
(5) pouring wall concrete
1, must meet the conditions of foundation concrete pouring.
2. The front and back fields are closely coordinated, and similar situations such as waiting for materials are not allowed.
3, prevent concrete collision, resulting in the separation of mortar and aggregate.
4, pay attention to the provisions of the layered casting thickness and intermittent time.
5, in the process of vibrating, should have full-time personnel, according to the hierarchical order to fully vibrate, no leakage of vibration, but not vibration, in case of bleeding.
6. Pay attention to check the displacement and deformation of formwork, reinforcement and support when pouring.
(6) Concrete curing
1, check the method and time of keeping in good health, organize keeping in good health in time, and fully moisturize in time even if the template covers the stage.
2, demoulding:
Side formwork: the strength of concrete must reach above 2.5Mpa.
Top formwork: When the span is less than 4m, the concrete strength must reach over 70%.
When the span is greater than 4m, the concrete strength must be greater than 75%.
(7) Quality requirements
1, the strength must meet the design requirements.
2, the length, width, height and elevation of each point should meet the requirements.
3, flatness, smoothness, verticality, blisters, honeycomb pits conform to the requirements of the specification.
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