First, the formwork project
1. Common quality problems in the construction of formwork projects. If the axis is offset, the elevation is not accurate, and the cross-sectional size is inconsistent with the design drawingsThe formwork splicing is not tight, the top is not firm, and it is deformed;Improper use of release agent materials;The time of demoulding is not strictly controlled.
2. Supervision and control measures.
The formwork and its support must comply with the following provisions: ensure that the shape, size and mutual position of each part of the engineering structure and components are correct: have sufficient bearing capacity, stiffness and stability, and can reliably withstand the quality and lateral pressure of the newly poured concrete and the load generated in the construction process. The structure is simple, the assembly and disassembly are convenient, and it is convenient for steel binding and installation, concrete pouring and maintenanceThe seams of the formwork are tight. In order to ensure the quality of concrete and its surface is smooth and tidy, it is advisable to vigorously promote the application of the new nine-clamp formwork, and ensure that the beams, columns, and plate joints are smooth and tidy, and the concrete joints are eliminated.
Strength inspection: Check that the template itself should have sufficient strength to meet the design requirements. If the strength is insufficient, the formwork will be deformed or even destroyed, and when pouring concrete, it will cause mold explosion and affect the concrete quality to varying degrees.
Stiffness test: check that the template itself should have sufficient stiffness to meet the design requirements. If the stiffness is insufficient, the formwork will be deflected and deformed, which will affect the quality of the concrete.
Stability inspection: check that the formwork support must be stable and firm, and the formwork support of the elevated platform must be stable and reliable. Therefore, the concrete construction of the elevated project must adopt the full support system, and the supporting formwork and scaffolding must have a design calculation, and the relevant structure and support measures must be stable and reliable.
Support inspection: The bracket of the elevated operation template must have enough effective supporting area, so that the upper load can be evenly transmitted to the bearing surface through the bottom of the bracket (cushion block, backing plate, skeleton beam, etc.). When the bottom vertical template or support is constructed, the support may be on the loose soil, and the base soil must be compacted, and its effective supporting area should be determined by calculation. There is a foundation for drainage, and a backing plate should be laid;The upper support column should be aligned with the lower support column, and the backing plate should be laid. When installing the upper formwork, the lower floor slab or beam should have the ability to bear the upper load, otherwise measures such as adding brackets and supports should be taken.
Waterproof inspection, such as the construction of the foundation cushion cap, as the foundation soil of the supporting support, must be surrounded by drainage ditches, collection wells and other waterproof measures.
Eliminate construction deflection inspection: cast-in-situ integral reinforced concrete beam slab, when the span is greater than or equal to 4m, the formwork should be arched, so as to eliminate the deflection caused by the weight of the structure, the weight of the equipment and the load of the construction personnel and construction machinery in the construction process. If the design is not specified, the arch height is controlled to be 1 1000 3 1000 for the full span.
Isolation agent inspection: according to a variety of different types of formwork, the selection of appropriate release agent, the selection of release agent should consider that the demoulding is easy, but no matter what kind of release agent is used, do not stain the steel bar, so as not to reduce the grip of the steel bar;It does not pollute the surface of the component, and has no damage to the concrete and steel bar.
Formwork installation quality inspection: check the geometric dimension flatness, finish, and seam width of the formwork must meet the requirements of the design and relevant specifications, and strictly prevent the occurrence of quality problems such as leakage, hemp surface, holes, and exposed ribs.
Inspection of orifice and embedded parts: the inspection is strictly in accordance with the requirements of the design and construction drawings to reserve the orifice, the embedded parts are tied firmly, and the position of the concrete protective layer cushion block is correct and reliable.
Second, the reinforcement project
In the reinforced concrete structure, the quality control of the steel bar as one of the main materials should be tracked and supervised from the beginning of the entry to the whole process before the concealment of the steel bar, and the supervision method of heavy concealment inspection and light whole process control shall not be adopted, so as not to cause the passivity of the supervision work and the leakage of quality hazards.
Common quality problems in steel reinforcement engineering. If the appearance quality of the steel bar is poor, the quality assurance data does not meet the requirements;The production and binding of steel bars are not standardized;Reinforcement is not arranged according to the design requirements, and the stressed reinforcement is offset, the size is not enough, or the joint position is not properly handledThe hook angle is insufficient.
For the quality of steel bars, our supervisors control and manage them from the following five aspects.
1. Acceptance of the use of steel bars.
1) After the steel bar enters the site, first check the product certificate, the factory inspection report, and the sign of each bundle (plate) of the steel bar, and witness the sampling in time for the retest test after meeting the requirementsCheck the entry re-inspection report before use.
2) The inspection batch of hot-rolled steel bars must be composed of the same diameter and the same furnace number, and the weight is not more than 30t of the billet smelted by the oxygen converter or electric furnace and the steel bar rolled by the continuous casting billet, and the steel bar of different furnace tank numbers with the same steel number and the same smelting and casting method is allowed to form a mixed batch, but each batch shall not exceed 6 furnace and tank numbers.
3) Appearance inspection: the steel bar should be straight, the surface should be free of damage, cracks, scars, folds and oil stains, and the surface of the steel bar should be allowed to have bumps, but not more than the maximum height of the transverse rib.
4) Check the steel bar as much as possible, the steel bar should be stacked in the warehouse or shed, when the conditions are not available, it can also be stacked in the open field, but should be selected to be higher terrain, there is a certain drainage slope of the place to stack, from the ground height is not less than 200mm.
2. Steel bar processing inspection.
1) Steel bar rust removal:
a. Identify the degree of corrosion. Poor storage of steel bars or storage for too long, the formation of rust on the surface of steel bars, rust is divided into three types: water rust (color rust), old rust and old rust, water rust makes the surface of the steel bar yellow-brown, generally can not be treated;The old rust is reddish-brown, and there is rust powder on the surface of the steel bar, which affects the adhesion between the steel bar and the concrete, so it must be cleaned up, the old rust is dark brown or black, and the steel bar has a granular or flake separation phenomenon, and it shall not be used.
b. Select the rust removal method. There are many methods of rust removal: derusting of steel bar derusting machine, derusting in steel bar straightening, manual derusting and pickling derusting, etc., which are selected by the construction unit according to the equipment conditions and reported to the supervision personnel for future reference.
c. Check the rust removal effect and release it if it meets the requirements.
2) Straightening of steel bars: Whether it is wire rods below 12mm or steel bars above 12mm, they must go through the straightening process before use. The quality requirements for straightening are: the steel bar is straight, there is no local twist or slow bending, and there is no damage to the surface.
3) Reinforcement cutting: check the size of the steel bar break, its deviation should be within the specified range, and the fracture of the steel bar shall not have horseshoe shape or bending, cracks and other defects.
4) The steel bar is bent and formed. The bending forming quality standards are as follows:
a. When the end of the stressed steel bar is hooked at 180 °, the inner diameter of the arc should not be less than 2 of the diameter of the steel bar5 times, the length of the straight part after the hook is not less than 3 times the diameter of the steel bar, when the end is 135 ° hook, the arc diameter is not less than 4 times the diameter of the steel bar, and the length of the straight part after bending meets the design requirements;The inner diameter of the arc at the 90° bend of the steel bar is not less than 5 times the diameter of the steel bar. At the same time, the length of the above hook shall not be less than the required length of the structure under the specified fortification intensity.
B, stirrup hook hook in addition to meet the requirements of the upper bar, should not be less than the diameter of the stressed steel bar;The bending angle of the stirrups should be 135° for structures with seismic requirementsThe length of the straight part of the stirrup after bending should not be less than 10 times the diameter of the stirrup for structures with seismic requirements.
c. The steel bar is formed correctly, and there is no warping and unevenness on the plane.
d. There shall be no cracks at the bending point of the steel bar, and the steel bar of grade II or above shall not be bent over the head and then bent back, otherwise this part should be used after being cut off.
e. The allowable deviation of steel bar bending and forming is: the net size of the full length is 10mm, the starting point of the bending steel bar is 20mm, the bending height of the bent steel bar is 5mm, and the net size of the stirrups is 5mm.
3. Steel bar welding inspection.
1) Choose the appropriate welding method. When reviewing the construction plan of the construction unit, it should be required to determine the selected welding method, and the welding method should comply with the steel bar welding and acceptance regulations (JGJ18-2003) in 41.1.
2) The operation requirements and acceptance of various welding methods should be in accordance with the provisions of JGJ18-2003.
3) Commonly used steel arc lap welding and electroslag pressure welding, the supervision requirements are as follows:
a. Arc lap welding of steel bars:
Before welding, the lap two steel bars should be fixed with two-point positioning welding, and the positioning weld should be more than 20mm away from the lap end.
The rebar axis offset at the joint is 01d, and 3mm, the bending of the steel bar axis at the joint does not exceed 3°.
Lap weld length: 8D for single-sided welding of grade I steel bar, 4D for double-sided welding, 10D for single-sided welding of grade steel bar, 5D for double-sided welding, and 0 for weld thickness3d, weld width 0 8d (d are the diameter of the main reinforcement).
Weld appearance inspection: the surface of the weld should be flat, and there should be no depression or weld nodulesThere must be no visible cracks in the welded joint area;Slight undercuts are allowed, the depth is 0 5 mm, a small amount of porosity and slag inclusion is allowed, and on the surface within a length of 2 d, the number of allowed is 2 and the permissible area is 6 mm2.
2) Electroslag pressure welding of steel bars:
Electroslag pressure welding is suitable for vertical or oblique steel bars, grade I hot-rolled steel bars 14 20mm, grade II and III hot-rolled steel bars diameter 14 32mm;
The axis offset at the joint is 0 1d, and 2mm, and the bending angle is 3°;
Visual inspection: there should be no burn defects at the contact between the steel bar and the electrode, and the welding ladle should protrude from the surface height of the steel bar by 4mm.
Mechanical properties are tested for steel arc lap welding and electroslag pressure welding joints, and 300 joints of the same level of steel bars are used as a batch every two floors or construction sections, and less than 300 are still done in a batch, and 3 specimens are randomly taken for tensile testing in each batch.
4. Rebar binding and installation inspection.
1) Lashing joint requirements:
a. The stirrup lap joint should be firmly tied with iron wire in the center and both ends, and the distance between the end of the lap and the stirrup bend is 10d, and the joint shall not be located at the maximum bending moment.
b. The minimum lap length of the longitudinal tensile steel bar, when the joint area ratio is not greater than 25, is specified in the following table:
When the area ratio of the reinforcement joint is greater than 25, the lap length is multiplied by the coefficient 12；When the joint area is greater than 50, multiply by the factor 135；In any case, the lap length is not less than 300mm.
2) Reinforcement installation:
The supervisors shall inspect all the connecting joints of the longitudinal stressed steel bars, and the connection mode shall meet the design requirements.
a. Installation of steel bar connection part:
Welded joint: the connection section is defined as 35d, and not less than 500mm, and the area rate of longitudinal stressed steel bars in the connection area is not more than 50, and they are staggered with each other.
Binding reinforcement: The connecting section is 1 of the lap length3 times, longitudinal stress reinforcement area rate: beam, plate, wall 25, when it is really necessary to relax, the beam can be relaxed to 50, other components according to the actual situation relaxed;Column members 50 and staggered from each other.
Stirrups: the stirrup spacing in the tension lap area should not be greater than 5 times the smaller diameter of the lap reinforcement, and should not be greater than 100mm, the stirrup spacing in the compression lap area should not be greater than 10 times the smaller diameter of the lap reinforcement, and should not be greater than 200mm, when the diameter of the longitudinal stressed reinforcement in the column is greater than 25mm, two stirrups should be arranged within 100mm range outside the two end faces of the lap joint, and the spacing should be 50mm.
b. Foundation reinforcement:
The steel bar on the short side of the foundation (including the foundation pile foundation cushion cap) should be placed on top of the long side steel bar, and the beam plate should be inverted.
The calculated raft foundation (according to the stress characteristics of the two-way slab) is mainly stressed on the reinforcement.
The stirrups of the cast-in-place column and the foundation connection should be one bar diameter smaller than the column stirrup, so as to be tied and connected, and the reinforcement must be fixed firmly to prevent the displacement of the column axis.
When the foundation base plate is double-layer reinforcement, a steel bar support foot is arranged every 1m below the upper reinforcement.
c. Column reinforcement:
The stirrup joints of the column should be staggered on the longitudinal reinforcement at the four corners.
The exposed part of the reinforcement of the lower column, it is advisable to retract a column reinforcement diameter, so as to facilitate the binding lap of the upper column reinforcement, when the column becomes cross-sectional, it must be before the binding beam, the exposed part of the column reinforcement is contracted accurately.
Reinforcements such as frame beams, corbels and column caps should be on the inside of the columns.
d. Beam and plate reinforcement:
At the intersection of the plate, the secondary beam and the main beam, the reinforcement of the plate is on the top, the secondary beam reinforcement is centered, and the main beam reinforcement is below;When a beam pad or ring beam, the main beam reinforcement is on top of the beam pad or ring beam reinforcement.
The joints of stirrups should be staggered on two erection reinforcements, and the cantilever beam reinforcement joints should be arranged in the lower part.
When the reinforcement mesh of the plate is tied, special attention should be paid to prevent the negative reinforcement from being stepped on, especially the cantilever beam plate such as awnings, beams, and balconies.
5. Key points of inspection before concealment:
Check whether the variety, specification, quantity and spacing of the longitudinal stressed steel bar are correct according to the design drawings.
Check whether the variety, specification, quantity and spacing of stirrups and transverse reinforcement meet the regulations.
Check whether the joint position, lap length and joint area ratio of the reinforcement connection method meet the requirements
Check whether the specifications, quantities and locations of embedded parts are accurate.
Check whether the protective layer meets the requirements.
Check whether the reinforcement binding is firm and whether there is any looseness;Check the surface for unacceptable oil stains and rust.
After the inspection is completed, the concealed acceptance shall be carried out according to the procedure, or the rectification opinions shall be put forward. Without the hidden inspection of the steel bar, the construction of the next process shall not be carried out.
3. Concrete engineering
1. Common quality problems in concrete engineering. Such as: the ratio is not standardized, the weight ratio is not implemented, the raw materials are unqualified, the water is not controlled, the concrete strength does not meet the design requirements, and the concrete surface appears honeycomb, hemp surface, holes, loose and cracksThe surface of the reinforced concrete is exposed, and there is slag inclusion at the construction joint;The phenomenon of "rotten roots" appears at the root of the cast-in-place concrete column;Missing edges and corners and surface cracks in the component;The bottom surface of the cast-in-place beam plate is deformed, etc.
2. Supervision and control measures.
The cement, aggregates, admixtures, etc. used to inspect the concrete must comply with the construction specifications. The quality of commercial concrete should comply with the provisions of "Ready Mixed Concrete". To monitor the quality of commercial concrete, it is advisable to inspect and select the concrete mixing plant with the construction general contractor, check and obtain cement, sand, stone and other quality information and concrete mix ratioDetect the concrete construction ratio, mixing time and the continuation time from the concrete being discharged from the mixer to the completion of pouring;Check the arrangement and working conditions of the pumped concrete, etc., which should meet the requirements of the specification, and it is strictly forbidden to add water arbitrarily and exceed the time limit without taking any measures.
According to the regulations, the use of commercial concrete, review the qualifications of the supplier, and review the mix strength of the commercial concrete must meet the design requirements to ensure the concrete strength grade.
Supervise and urge the construction contractor to make concrete test blocks on site according to the regulations, and the supervision and witnesses witness the scene.
Before pouring concrete, strictly review the rationality and effectiveness of the pouring plan, especially the pouring of over-length large-area concrete and vertical structures.
The inspection of construction joints, deformation joints, wall pipe fittings, formwork iron and other settings and structures must meet the design requirements and construction specifications.
In the process of concrete pouring, dynamic supervision of pouring quality is implemented, including side stations, inspections and follow-up supervision. Control the position of the construction joint: beam - the main beam should not be left with the construction joint;The secondary beam construction joint can be left in the middle of the span 1 3 section;The cantilever beam should be poured as a whole to the structure to which it is connected. Plate - one-way plate construction joint can be left in any position parallel to the main reinforcement, or the span 1 3 places perpendicular to the stressed main reinforcement;The position of the two-way plate construction joint should be retained according to the requirements of the design institute. Column - the construction joint should be left at 20 30mm below the elevation of the bottom of the beam or at the elevation of the beam and plate surface. Wall - the construction joint should be left in the door opening beam span 1 3 section;It can also be left at the junction of the longitudinal and transverse shear walls. Large-section beams, thick plates, columns with a height of more than 6m or large-volume concrete should be seamed according to the requirements of the design institute. General provisions for continuing to pour concrete at the construction joint: the compressive strength of the concrete that has been poured is 12n mm2 (determined according to the schedule of temperature, cement, concrete inspection specifications);Remove the cement film on the surface of the concrete, loosen the stone and the weak concrete layer, and fully moisten and rinse clean, and do not accumulate water;Lay a layer of cement slurry or cement mortar at the construction joint;The concrete should be carefully tamped, so that the old and new concrete are closely combined;Care should be taken not to allow the vibrator to touch the steel bars or hardened concrete at the contact point.
General provisions for concrete pouring: before pouring - check the formwork and its support, steel bars and embedded parts and reserved holes;Supervise and clean up the debris in the mold and the oil stains on the steel bars, plug the gaps and holes in the formwork, and water and moisten the formwork, but no water shall accumulate in the mold. When pouring concrete, the free height of concrete falling from a height shall not be greater than 2m. Segregation shall not occur in pouring, and when the pouring height exceeds 3m, string cylinders, slip pipes, etc. should be used to guide the concrete to fall. In the process of concrete pouring, the formwork, support, embedded parts and holes should be observed frequently, and measures should be taken in time to deal with the deformation or displacement when found. When pouring beams and slabs with columns and walls as a whole, they should be stopped after the columns or walls are poured for 1-15 hours, and then continue to pour, can avoid the crack of the concrete of the joint between the column or wall top and the beam plate;Beams and slabs should be poured concrete at the same time, when the height is greater than 1m of beams or slabs, concrete can be poured separately. Concrete column segmented pouring - column section 40 40cm within 40cm, and no cross stirrups, each section height 35m；When the column section is greater than 40 40cm, or there are cross stirrups, the height of each section is 2m, and the door opening on the mold side is adopted, and the inclined groove is poured in sections.
Concrete vibration requirements: the effective depth of concrete vibration - the effective depth of vibration of the plug-in vibrator is 1 of the length of the vibration action part25 times;The effective depth of vibration of the hand shaker is: 200mm for single or non-ribbed board, and about 120mm for double rib board. The vibrating time of the plug-in vibrator should make the concrete surface present a floating slurry and no longer settle to degrees;When vibrating, it is necessary to do fast plugging and slow pulling, each point of vibration time is not less than 10 seconds, the moving distance is generally about 300mm, and the depth of inserting the lower layer of concrete is about 50mm. The vibration time of the hand shaker - the continuous vibration time of each position is controlled at 25 40 seconds, and the front and rear lap length is 30 50mm. The concrete vibration at the construction joint of the rib plate is often not equal to the concrete strength of 12n mm2, it is necessary to continue pouring and pounding, in order to make the newly poured concrete dense, and do not affect the quality of the original pouring concrete, the plug-in vibrator is required to vibrate from the construction joint about 300mm;The hand plate vibrator should vibrate from the side far away from the construction joint, and vibrate to about 30mm away from the construction joint to stop dragging forward. Check the concrete slump and the production of concrete specimens according to the regulations.
Concrete curing: cement is a hydraulic cement, the purpose of concrete curing, in order to make the concrete have suitable hardening conditions, to prevent shrinkage cracks, so we must attach great importance to the maintenance of concrete, check the contractor in strict accordance with the construction plan to implement maintenance, especially for the length of large area of concrete to strict temperature monitoring. In strength does not reach 1It is not allowed to work on it before 2MPa. Curing time - generally 12 hours after the concrete pouring (early summer can be reduced to 2 3 hours) to start, covering watering and curing more than 7 days and nights, mixed with retarding admixtures or impermeable concrete requirements, generally not less than 14 days and nights.
Trimming of concrete defects: After the concrete structure is dismantled, when concrete defects such as honeycomb, exposed stones, and exposed ribs are found, the contractor is not allowed to repair it by itself, and it should be reported to the supervising engineer for inspection, and repaired differently according to the severity. According to the severity of the defect, discuss the corresponding treatment methods, make a record, for the defects that affect the structural performance, the design unit must be jointly studied and treated, and the design consent can be repaired. And the construction unit fills in the "concrete defect repair record", which is archived after countersigning. The conventional concrete defect trimming treatment method is as follows:
The honeycomb with a small area and a small number, or the surface of exposed stone concrete, is first brushed with a wire brush, and after the base is washed with pressurized water, it can be used 1:2 or 1:25. Cement mortar smoothing.
Larger areas of honeycomb, exposed stone and exposed tendons, should be chiseled according to its full depth of the weak concrete layer and individual protruding orthopedic particles, and then with a wire brush, pressurized water to wash the surface, and then with a higher level than the original concrete strength grade of fine stone concrete plugging, and carefully tamped.
Section 8, the technical focus and supervision countermeasures of the load-bearing support of the large-space and large-span formwork.
This project is designed with a large span space, and a large span (L 9000) and a large space (H 6000) load-bearing bracket need to be erected. The load-bearing support should be designed according to the engineering structure form, load size, construction equipment and materials, etc., and the load-bearing support should have sufficient bearing capacity, stiffness and stability, and can reliably bear the weight of pouring concrete, lateral pressure and construction load.
1. Construction difficulties:
1) Large space, large span.
The height of the load-bearing support is high, the span of the concrete beam is large, the stiffness is small, the stability is poor, and the scaffold steel pipe needs to be reliably connected. In recent years, similar load-bearing support collapse accidents have occurred from time to time in China.
2) There are many hidden dangers of safety accidents in high-altitude work.
In the process of erecting the load-bearing support, most of them are high-altitude operations, and there is also the cooperation and coordination of professional scaffolding construction personnel and formwork construction personnel, which can easily cause the first accident of falling from high altitude.
2. Supervision countermeasures.
1) Carefully review the construction plan of the load-bearing support and formwork, and review the key points: the calculation of the bearing capacity of a single member, the calculation of the overall stability of the frame, and the structural measures of the load-bearing support (such as whether the setting of the sweeping rod, scissor brace, the step distance of the longitudinal and horizontal connecting rods and the connecting parts of the main structure is reliable and reasonable). After the plan is approved, the frame can be erected.
2) Carefully inspect and accept the construction quality of load-bearing supports and formwork.
Check the quality of the steel pipe, where there are punched, bent steel pipes shall not be used;Check whether the torque of the fastener meets the requirements of the acceptance specification;Check whether the step distance of the sweeping rod, scissor brace, and longitudinal and horizontal connecting rod is set in accordance with the construction plan;Check whether the connection between the load-bearing support and the main structure (frame beam, column, concrete wall) is reliable, and the concrete pouring construction can only be carried out after passing the inspection and acceptance.
3) steel bar binding construction, must be erected horse road, high-altitude work, construction personnel must fasten the safety belt, supervision engineer in the construction process strict inspection, construction personnel are strictly prohibited from throwing items;The formwork should be carried out in accordance with the prescribed operating procedures, and the next process construction shall not be carried out before the template is fixed.
Section 9, civil air defense engineering construction priorities and supervision and control measures.
The basement of this project may be designed for air defense, which is used as a garage in peacetime, a personnel shelter and a material warehouse in wartime, and some of the rooms are non-civil air defense areas. In the construction process, the construction should be carried out in strict accordance with the requirements of the design drawings and the construction and acceptance specifications of the civil air defense project.
Production and installation of orifice protection facilities
Orifice protection facilities include protective doors, protective airtight doors and airtight doors, etc., because orifice protection facilities have the requirements of explosion-proof, smoke-proof and other functions, requiring accurate size, firm structure, tight joints, smooth surface, and difficult construction, so it must be constructed by professional manufacturers. At the same time, it is also necessary to cooperate closely with the civil engineering unit during the construction process to meet the requirements of the design and construction specifications.
The supervising engineer should strictly review the qualifications of professional manufacturers;The product quality certificate of the protective facilities shall be complete;Check that the parts of the facility are complete;Whether the number of model names meets the design requirements, and check the appearance quality of products and parts.
Check whether the specifications and dimensions of the embedded parts meet the design requirements, and whether the embedded positions are accurate and reliably fixed, and ask the relevant units to countersign for confirmation. Products, parts, and embedded parts should be rusted and treated with anti-corrosion, whether they are qualified.
During the installation process, the supervising engineer checks whether the flatness and verticality of the product meet the requirements of the construction acceptance specifications, and checks whether the door leaf and the door frame fit evenlyThe hinge and latch installation position should be accurate, and the coaxiality deviation of the upper and lower hinge pages should not exceed 1% and 2mm of the distance between the two hingesThe outer surface of the door leaf should be marked with the direction of the latching switch;Check the quality of the installation and construction of the sealing strip, and should meet the requirements of the construction acceptance specification.
The air wall and board are blocked during wartime.
According to the requirements of the use function of the project, it is necessary to open doors and openings on the empty walls and boards of the civil air defense project. In order to ensure that the role of civil air defense engineering can be brought into play in wartime, it is necessary to carry out wartime sealing of such doors and openings in wartime. Therefore, in the process of construction of the main structure of the basement, effective measures must be taken to create favorable conditions for the future wartime blocking. The supervising engineer should strictly inspect the quality of the production, installation and construction of the embedded connectors of the door and the opening, check whether it meets the design requirements, and should take into account various influencing factors in the future wartime blockade to ensure that the wartime blockade can be implemented smoothly.
Installation and construction of pipelines and accessories.
In the walls and slabs of the basement, there are a large number of reserved holes and equipment pipes. When the pipeline passes through the airtight partition wall of civil air defense protection. It is necessary to pre-embed a closed wall stub that often has a closed wing ring and protective resistance parts. When the pipeline passes through the closed partition wall, it is necessary to pre-embed the closed short pipe through the wall, which often has a closed wing ring.
The supervising engineer should strictly control the following points during construction:
Water supply pipes, pressure drainage pipes, cables and wires should be made according to the design requirements, and the wall thickness shall not be less than 3mm, and the product quality certificate of raw materials shall be complete.
The closed wall short pipe of the general pipeline should be welded with a thickness of 2-3mm, and the weld should be full, uniform and tight.
The airtight wing ring should be made of steel plate with a thickness greater than 3mm. The joint part of the closed wing ring and the closed wall stub should be fully weldedThe airtight wing ring should be located in the middle of the thickness of the wall and should be welded firmly with the surrounding structural reinforcement. The axis of the closed short pipe through the wall should overlap with the wall where it is located, and the surface of the pipe section should be flat.
The closed wall stub should be equipped with a protective anti-resistance piece in the band facing the shock wave of the nuclear explosion. The resistance sheet should be made of steel plate with a thickness greater than 6mm.
When the hidden piping of the cable and wire passes through the protective airtight partition wall or airtight partition wall, a wire box should be set on both sides of the wall, and there shall be no joints in the box.
If there is a hidden box at the empty wall and plate, the reinforcement structure measures at the place should meet the reinforcement structure requirements of the civil air defense project. At the same time, make sure that the concrete slab is 200mm thick.