Control point measurement and setting
Firstly, the red line control point given by the municipal planning department is checked, and then the control point of the project is set according to the shape of the building as the basis for the axis measurement and release.
The project has 4 axis control points to form a control network. Control points should be set up semi-permanently with concrete, steel piles, or wooden piles.
The standard control point of the municipal planning department given by the construction unit measures and sets the level control point used in the project as the basis for elevation measurement. And each time before the elevation measurement, the semi-permanent leveling point should be checked to confirm that the leveling point has no change and the elevation value is accurate before the measurement.
After the completion of the measurement and design of the axis control point and the level control point, the relevant departments (planning department, construction unit, supervision unit) shall properly protect the line after passing the inspection, and draw a detailed location map for future reference.
Positioning and axis measurement and release of buildings
According to the positioning basis given by the design and the positioning conditions of the red line, the N2 level theodolite is used to measure the positioning of the building.
Considering that this project is a 5-storey building above ground, the building height is only 22About 70 meters, in addition, the site around the project is relatively open, and the plane measurement control network adopts the external plane measurement control network in the form of a cross measurement axis, that is, the measurement axis direction point is projected to the vicinity of the project and the standard pile is buried. The measurement axis deviates 1m parallel from the corresponding building axis (the purpose is to ensure that the line of sight of the instrument is not blocked by the column reinforcement when measuring the pay-off).
The measurement basis point is the red line point, and the distance of the red line point is measured, and the difference between the measured value and the theoretical value is checked whether it is within the allowable range of the specification. Based on the red line point, the intersection point of the building axis is measured and set up on the spot, and then the point is measured and set on the ground based on this, and the direction point of the measurement axis is projected to the vicinity and the stake is buried.
After the measurement axis is set to the ground, the relevant geometric dimension relationship between the measurement axis and the starting measurement control point (line) and the orthogonality of the long and short measurement axis are remeasured and adjusted firstly, so as to ensure that the length and short measurement axes of the building are perpendicular to each other, and the difference between the relevant geometric dimensions of the measurement axis and the starting measurement control point (line) and its design value is within the scope of the specification requirements. The spacing and angle of each control point are checked with theodolite and steel ruler, and the deviation is not more than 2mm and 10 respectively compared with the design length and angle"and make a record of the measurement data.
Measurement and pay-off of the structural part of the building: Based on the external measurement and control axis, a positive and inverted mirror is erected on the construction, and the measurement axis is projected onto the concrete surface of the construction (the measurement axis is bounced on the concrete surface with an ink line), and the construction team controls the positioning and pay-off of columns and beams according to the measured measurement axis.
Measurement and pay-off of the construction part of the building: The measurement axis projected during the construction of the structure (the concrete slurry at the measurement axis is removed, and the ink line will be revealed) is set up to measure the building axis to the column, which is used to control the positioning and pay-off of the interior and exterior walls.
Elevation measurement of a building
When carrying out the elevation survey of the above-ground works, 0. is set on the external wall columns on the first floor of the building00 line or 10m elevation control line, using steel ruler upward sectional guidance. There are no less than 4 elevation control lines.
When the lead height exceeds the length of one full foot, the second elevation guide line is set. The elevation of the construction layer that has been completed by the introduction should be checked and measured by using the level, and the construction can only be continued after meeting the accuracy requirements.
The induction steps are:
1. Use the level (S2 level) first to measure 0000 line, fixed pile (point);After control, the same starting elevation line is accurately measured at the introduction point, generally 500 or 1000 elevation.
2. Use a steel ruler to measure up to the construction layer along the straight direction of lead, and the 500 horizontal elevation line of each layer should be measured, and the elevation line is directly measured from the starting elevation line here.
3. Place the level on the construction layer, and calibrate the horizontal line transmitted from below, which should be within 5mm. At the leveling, the two horizontal lines should be checked backwards.
Key points when applying elevations:
1. The front and rear sight distances must be of equal length or approximately equal length;
2. The steel ruler must be tested by the measurement department before use
3. It is not suitable to level at high temperature at noon, and it is strictly forbidden to work under high temperature and exposure to the sun.
Building verticality control
The verticality control of each unit of this project adopts the method of combining "external control method" and "internal control method" to check and control. That is, the verticality of the outer contour of the building is controlled by the theodolite at the four corners and the axis of the first floor is used as the benchmark to measure and check the deviation. When controlling the verticality of the internal axis and wall columns, the laser theodolite is used to project the control points upwards, and the line hammer is used to check the verticality of the building. Generally, it is checked every 5 layers.
The verticality control of the wall columns on each floor is checked by a line hammer and a theodolite. After the completion of the construction of the structure, the verticality deviation of the axis of each floor of the completed project will be measured immediately so that the adjustment can be made in time.
Choose a windless and cloudy day in the morning or evening, measure the verticality of each second floor of the building with a laser theodolite, find the problem and eliminate it in time, strengthen the axis control and reinforcement of the side column and side beam formwork, and prevent the misalignment, mold running, mold expansion and axis displacement of the outer edge components of the building.
Subsidence observations
Settings for Settlement Observation Points:
1. Set up settlement observation points according to the requirements of the design drawings.
2. The settlement observation point itself should be firm to ensure the safety of the point and can be stored for a long time
3. There must be obvious protrusions on the observation point, and keep a certain distance from the column and wall.
4. How to set up:
Settlement observation methods.
Instruments used: S2 level and tower ruler;
Before each observation, the reference point must be reviewed, and then set up on the side of the building, the rear reference point, the front view settlement observation point, obtain the observation data, and make a record. Each observation must be carried out by three people, one observation, one review, and one ruler. The resulting data is calculated to arrive at this sedimentation. Before the completion of the project, the settlement value is plotted as a settlement observation curve.
Settlement observation time requirements:
1. After the observation point is set, it will be observed once as the original data
2. During the construction of the main structure, each layer is observed once;
3. Observe once a month during the decoration period;
4. Observe once before completion;
5. Do a good job in the layout map and observation record of the settlement observation point, and draw the settlement observation value into the settlement observation curve before the completion of the project
6. If abnormal settlement is found after each observation, the relevant units should be notified immediately to take joint measures
7. When making the first observation, it must go through two rounds to ensure the accuracy of the first observation
8. Before the completion of the project and the inspection, permanent observation points can be set up according to the construction unit and design requirements.
Key points of earthwork excavation construction:
1. Before excavation, the surveyor should first pay off, and sprinkle it with gray line, and then carry out earthwork excavation after review.
2. During the excavation construction, the excavation depth of each component (part) should be observed at any time and strictly controlled to prevent over-excavation.
3. Before backfilling the foundation pit, remove the turf, tree roots, bricks, stones and other debris on the baseLevel the base and tamp it.
4. Backfill quality requirements.
The soil material is made of clay dug out of the foundation pit, which does not contain organic impurities, and is screened before use, and its particle size shall not be greater than 15mm, and the water content shall be properly controlled during construction. The compaction density of the site is required to meet the design requirements. The thickness of each layer of plain soil is 200-250mm, and the number of times each layer is 3-4 times of vertical and horizontal ramming. Before tamping, the fill is initially leveled, and the tamping machine is tamped in turn, evenly distributed, and no gap is left;Plain soil shall not contain organic impurities, sieve before use, and its particle size shall not be greater than 15mm;The site plain soil should reserve about 3% of the sinking height;The fill starts from the bottom and is paved and compacted in layers from top to bottom across the entire width.
5. According to the amount of backfill earthwork, part of the earthwork is stacked on the site, and the rest is transported to the designated place off-site for stacking.
1. Raw material requirements:
a. The steel bars used in the project are:
Grade reinforcement: fy=270N mm2
Grade reinforcement: fy=360n mm2
B, steel bar is a quality control material, steel raw materials in addition to the factory quality certificate, but also need to do mechanical properties test and weldability test as required, factory quality certificate and mechanical properties report both to be complete, if the use of imported steel, should also do chemical composition test. The test and inspection results of the steel bar should meet the relevant provisions and requirements in QB1499-91 "Steel Bar for Concrete Engineering". The unqualified steel bars shall be resolutely cleared and shall not be used in this project.
2. Preparation of steel bars.
Before construction, organize technical personnel to make disclosures, and prepare corresponding quality control measures and work instructions, arrange lashing sequences, emission rules, and main construction methods, clarify quality and construction period requirements, and solve difficult points in construction.
The steel bar should be constructed in strict accordance with the drawings, read the drawings and design changes in detail before cutting, the steel bar material list should be divided into the engineering parts and specific locations, the inspection of the material list is responsible for the technical personnel in charge of the construction site, the steel bar is made and formed in the processing plant, the hanging material card is stacked and stacked in a classified manner, and before being transported to the site, the blanking personnel should cooperate with the construction staff to classify and give the low-down.
3. Connection of steel bars.
According to the requirements of the design drawings, there are two ways to connect the steel bars of this project:
The beam reinforcement is connected by flash butt welding.
The longitudinal reinforcement is connected by vertical electroslag pressure welding.
When there are multiple steel bars in the same component that need to be connected, the number of lap steel bars in the same section shall not exceed 50% (for columns) or 25% (for beams) of the total number of steel bars, and the staggered spacing of joints shall not be less than 45d. The connection of the steel bars of the vertical components of this project starts from 500 on the floor slab.
The bottom reinforcement of simply supported beams and continuous beams shall not be lapped within the range of L0 3 (L0 is the net span) in the middle of the span, and the gluten shall not be lapped within the range of L0 3 near the support;The net span of the cantilever beam is less than the length of the raw material of the rebar, so lap joints are not allowed.
The plate gluten is lapped at the middle of the span, and the bottom reinforcement is lapped at the support.
4. Anchorage and node structure of steel bars
The anchorage length lae is shown in the table below.
b. Frame column.
The reinforcement of the frame column at the variable section is bent and straight through according to the 1:6 slope shown in the drawing, and if the 1:6 slope condition cannot be met, the reinforcement needs to be reinserted. When all kinds of reserved, embedded pipes and holes need to pass through the column, try to avoid the column reinforcement, if it cannot be avoided, the vertical reinforcement of the column is bent around the hole according to the slope of 1:6.
c. Beam reinforcement. When the longitudinal and longitudinal beams intersect, the main reinforcement at the bottom of the frame beam is put down in the row, and when the same is the frame beam, the main reinforcement of the short frame beam is put down in the row, and the secondary beam intersects with the frame beam, and the steel bar of the secondary beam beam surface is placed in the upper row.
All beams when the beam width B 350, H 700 using two limb hoops, B 350, H 700 using four limb hoops, stirrups should do 135 ° bending hook, bending hook straight section should not be less than 10d.
No rebar joints are allowed within the stirrup infill zone at the beam end.
When the beam is level with the column edge, the outer concrete protective layer of the beam is increased to place its reinforcement on the inside of the column reinforcement.
The beam remains in the hole in strict accordance with the requirements of the design drawings to bury the steel pipe and stiffeners, and shall not be omitted to carry out chisel.
d. Plate reinforcement:
The bottom reinforcement of the plate is anchored into the support and passes through the centerline of the support for not less than 5d, and the plate gluten is anchored into the support for not less than 35d.
In the two-way plate, the bottom rib is placed in the lower row parallel to the short side, and the one parallel to the long side is placed in the upper row. When the bottom of the slab is equal to the bottom of the beam, the lower reinforcement of the slab should be placed on the main reinforcement of the lower part of the beam. The embedded pipe in the plate must be laid between the upper and lower layers of reinforcement mesh in the plate, and when there is no plate gluten at the buried pipe, additional steel bars need to be added along the direction of the pipe length. As shown below:
When the diameter or side length of the hole on the board is 300mm, the plate reinforcement continues, and it passes around the hole;l 300mm, according to the design requirements of the hole side stiffeners.
5. Rebar binding in place:
a, the same layer of components first bind the column, and then bind the beam plate, when the column main reinforcement and the beam plate reinforcement conflict, must ensure the position of the column main reinforcement.
b. The joint position, anchorage length and lap length of columns, beams and plate reinforcements should meet the design and specification requirements. As a key process, steel bar binding should be supervised and monitored by quality inspectors throughout the construction process.
c. The stirrups in the core area of the column are welded core hoops, which are processed in advance and transported to the binding site. As shown in the figure:
d. The bottom reinforcement of the plate adopts the method of marking on the template to control the spacing, and the stool is used to control the thickness of the plate. As shown below:
e. This project is a second-level seismic requirement, and the ends of the frame beam and column stirrups must be made into a 135° hook, as shown in the following figure
f. The thickness of the protective layer of the reinforcement is ensured by the cushion block with the same grade as the concrete, and the cushion block is tied to the main reinforcement with a tied wire.
g. Be careful when binding steel bars, use 22 steel wires for binding wires, and each intersection should be tied without falling buckles.
h. Pay attention to the protection of the finished product, and the steel bar shall not be polluted after the completion of the binding to avoid being bent by heavy objects.
I. Before pouring concrete, nine plywoods should be padded on the plate reinforcement as a construction horse road to prevent the heavy pressure of personnel load during construction to collapse the upper steel bar, affecting the stress of the floor slab.
1. The support of the template.
Configure a complete set of templates, use them according to the classification and number of specific construction parts, and clean up, brush and classify before and after the mold is dismantled.
According to the order of component construction and taking into account the concrete strength growth and demoulding requirements, 3 sets of beam and plate formwork and 3 sets of column formwork are configured to effectively ensure the construction period.
Before construction, the project engineer organizes the construction personnel to make a disclosure, clarify the position of the main axis and the relationship with the position of other components, explain the intention of the drawings to the construction personnel, solve the difficult problems in the drawings, and make the construction personnel in charge of each section have a comprehensive understanding of the construction technology and construction focus, and are clear about the quality requirements and construction period control objectives, and then the construction personnel explain to the operators.
After the steel engineering inspection is qualified, the manager will notify the relevant construction personnel to carry out the column formwork support. Before erection, the position and quantity of embedded iron parts, pipes, and holes should be reviewed in detail according to the drawings to see if they are correct.
The formwork support sequence in each construction section is:
Beams, floors, columns, beams, walls, column heads.
The column formwork is made of nine plywood, reinforcing ribs 50 100mm wood square and 48 3The configuration of the 5mm steel pipe is adjusted according to the column shape, as shown in the figure below, and the T-column formwork is referred to the figure below.
The beam formwork is made of nine plywood, and the reinforcing ribs are made of 50 100 wood squares and 485×3.5 steel pipe matching, when the beam height exceeds 600mm, add wall bolts, bolts through the "3" type card, nuts and reinforcing ribs and other connections, bolt transverse spacing is 600mm, vertical row distance to see the specific height of the beam is determined, beam height 600 800 plus a. The bottom of the beam is first processed into wooden slats (blocks) on site, and the side side is left with a fork according to the position of the cross beam. See image below
According to the load calculation results, the spacing of the large cross-section beam top frame is shortened, and steel pipe belts and supports are added.
When the beam spans l 4m, the beam bottom die arches, when the design has no specific requirements, the arching height is 2 span length, cantilever beam pre-arch l 300, curved beam pre-arch l 400.
The plate mold is made of nine plywood panels, and the red shelves are used to reinforce the wooden square and steel pipes, as shown in the figure below
The column head, beam head and wall head are processed and used on site according to the specific structure size of the nine plywood, and it should be noted that the reinforcement must be firm and reliable, and the joints must be strict to ensure the quality.
In order to solve the problem of dislocation that often occurs on the upper and lower walls of the exterior wall and the stairwell, a wooden square can be added after the lower layer of concrete is poured, and then the upper layer template is supported on the wooden square, as shown in the following figure:
2. Template acceptance.
After the formwork is erected, the constructor and the quality inspector will jointly check whether the cleaning, reinforcement and joints of all the formwork meet the requirements with the team leader, and review the position, flatness and verticality of the formwork, fill in the self-inspection record after confirming that it is qualified, and submit it to the technical department for re-inspection. After passing the inspection, the technical person in charge of the site shall notify Party A of the supervision and quality supervision of the tripartite acceptance, and the concrete can be poured only after the acceptance is qualified.
3. Template dismantling.
The dismantling time of the formwork is determined according to the strength of the curing test block under the same conditions.
The column and beam side formwork can be dismantled after the concrete strength can ensure that its surface and edges and corners are not damaged by the removal of the formwork. Beam, plate bottom mold, in the concrete strength to meet the following table conditions, can be removed
It is strictly forbidden to dismantle the formwork and the support and reinforcement system at will without the notice of the technical personnel and the operator arranged by the constructor.
1. According to the schedule, one month before the pouring of the components, the technical personnel shall apply to the laboratory of the commercial concrete company for the concrete mix ratio. When applying for a mix ratio, it is necessary to provide the laboratory with performance requirements such as concrete labeling, construction site, slump, and water-cement ratio.
2. The concrete used in this project is mainly commercial concrete, and the quality requirements of concrete are subject to the concrete mix ratio notice and the technical notice issued by the site technical department according to the actual construction needs.
3. The method of concrete pumping is used for pouring, and the construction should try to avoid the occurrence of undue construction joints and affect the overall structural quality.
4. Before pouring concrete, together with the constructor and the quality inspector, the operator is clear about the pouring sequence, method, vibrating point layout, construction route and some special parts of the concrete pouring should be taken, and clear quality requirements, before each pouring concrete, the transfer pump, vibration machinery and other construction machinery are comprehensively debugged to prevent failures in the pouring process and affect the quality of concrete.
5, before pouring concrete by the technical person in charge of water, electricity, fire protection, and other related installation professions involved in the review, to participate in the review of the professional need to carefully review the drawings, check the site, after the acceptance of the person in charge of the concrete pouring notice to sign before pouring concrete.
6. At the intersection of concrete components of different grades, steel plate mesh partition partition is adopted. At the junction of beams, plates and columns, they are handled as follows:
7. Clarify the reward and punishment system of "who is responsible for construction" within the construction team, and mark the name of the main pouring personnel on the part (structure) after each pouring, so as to strengthen the sense of responsibility of the operator.
8. For the parts of the beam-column joints and other steel bars that are dense and cross repeatedly, as a special part of the structure, the concrete should be poured with more careful care, which can be considered
Choose a smaller mix ratio of coarse aggregate.
Vibrating rods under the sparse side reinforcement.
Choose 25 45 (7m) vibrator system.
Segmented layered vibration and other measures.
The purpose is to make the concrete of this part vibrate and compact and avoid leakage vibration and affect the quality of concrete.
9. Before pouring the vertical component concrete, clean the chisel surface of the old and new concrete joints, and pour the mortar of the same grade 30 50mm thick. This part of the mortar should not be transported by a conveying pump, and can be transported by a derrick. When pumping concrete, the pump port discharge is not allowed to directly impact the formed steel bar.
10. The concrete of the column and beam is vibrated by a plug-in vibrator, and the plate concrete is vibrated by a plate vibrator. When pouring concrete in layers, the vibrating rod should be inserted into the lower layer of concrete more than 5cm to ensure the quality of the concrete joint. The concrete vibration should be dense, but it should not be overvibrated and cause the mold to expand or even run the mold.
11. After the concrete pouring is completed, the concrete surface is scraped flat with a scraper, then smoothed with a wooden trowel, and finally pressed again with a wooden trowel before the initial setting of the concrete to reduce the surface cracks of the concrete.
12. In the process of concrete pouring, without the consent of the technical director, no one shall change the mix ratio at will, and leave the test block in accordance with the following provisions:
Not less than one group per 100 trays and not more than 100m3.
There is no less than one group for each layer.
Each layer is set up with a group of test blocks with the same conditions as a mold removal test block.
13. Assign a special person to be responsible for concrete maintenance, and vertical components such as columns are watered with water pipes or sprayers at any time to protect the concrete surface from moisture, and the poured slab concrete can be used to store water and water the method to keep it wet. Generally, the concrete curing time is not less than 7 days and nights, and the impermeable concrete curing time such as the water tank is not less than 14 days.
1. Construction preparation
1. Before construction, the technical department shall propose a material plan, and the material department shall be responsible for arranging the entry of materials on time and in full.
2. The engineering and technical team first prepares a detailed technical disclosure and organizes workers to learn the on-site disclosure.
3. Prepare other materials and tools, such as cement, sand, dump trucks, trolleys, scaffolding, bricklayer tools, etc.
Second, construction measures
1. Be familiar with the construction drawings, and clarify the location, elevation and structural column position of the door and window openings. The retention of structural columns should be subject to the drawings, and if the drawings are not clearly stipulated, they should meet the requirements of the relevant masonry construction specifications.
2. Before masonry, pop up the wall edge line, door and window opening line, structural column position line, etc., pop up the ash seam line on the wall, the elevation of the door and window opening, etc., and set up the skin number rod at the corner of the wall, and check the line by technicians and constructors.
3, masonry and concrete structure of the tie mainly adopt the method of burying the wall reinforcement, in the column every 500 high pre-embedded 2 6 steel bars, this reinforcement is buried in the column 250, exposed 700, and should not be less than 1 5 wall length.
4. The door opening is buried with anti-corrosion treated wooden bricks according to the regulations.
5. The brick wall should be staggered masonry, and the water and electricity pipelines should be connected before masonry, and at the same time, the line should be tried before plastering, so as to avoid chiseling afterwards.
6. Set lintels at the openings of doors and windows as requiredThe setting of lintels must be constructed according to the design requirements.
7. The masonry scaffold adopts the combination of the outer scaffold and the indoor gantry, and when the frame is finally removed, the rod hole should be blocked with mortar for each step of the frame.
8. The mortar mix ratio should be accurate, so that the material is exhausted. The mixed mortar should be used up as soon as possible, and it is strictly forbidden to leave the mortar overnight to make it agglomerate.
3. Wall plastering
1. The plastering shall be carried out one week after the completion of the masonry, and the construction shall be carried out only after the intermediate acceptance of the quality of the masonry project.
2. The mortar used in plastering should meet the design requirements. Its mix ratio and performance should be inspected before it can be used.
3. Before plastering, check whether the position of embedded parts and reserved holes is correct, and fill the ash joints and holes of the wall to remove the floating ash.
4. The average total thickness of the plastering layer shall not be greater than the following provisions:
Interior wall: Intermediate plastering: 20mm;
Exterior wall: Intermediate plastering: 20mm.
5. Plastering must be carried out in layers. The thickness of cement mortar should be 5 7mm;The previous layer should be dried after 7 8 is dry, and the latter layer can be wiped. Before large-area plastering, the mortar used for repairing and leveling should be consistent with the mortar used for large-area plastering. The plastering surface layer shall not have blasting ash and cracking. The bond between the plastering layers and between the plastering layer and the masonry should be firm, and there should be no defects such as delamination and hollowing. All kinds of plastering mortar should be protected from exposure to the sun, rain, water washing, impact and vibration before condensation. The plastering layer should be cured under wet conditions.
6. The sunny corners and column angles of all door openings and walkways are made of 20 thick l:2 cement mortar corner protection, with a height of 1800mm and a width of 80mm.
7. Buried dark lines, hidden pipes and other holes and grooves should be filled and smoothed with cement mortar first, and used fiber mesh or steel mesh for anti-cracking treatment, and then layered plastering.
8. The hollow brick exterior wall plastering is made of M10 fiber cement mortar with a base of 12 thickness, mixed with 5% cement heavy waterproofing agent, and the steel plate mesh is hung when plastering, and then leveled with M10 fiber cement mortar 8 thick, and finally made polymer cement-based waterproof coating 15 thick.
9. When the design requires the steel mesh to be hung full, the steel mesh should be nailed with nails and then plastered. The base should be cleaned before hanging the net, and the base should be flat, if it is uneven, it should be smoothed with the same mortar as the plastering mortar, and then after its initial setting, the metal mesh will be compacted with cement mortar before the final setting. The spacing of the nails should not be too large, and the steel mesh should not be deformed and arched. The plastering layer and the base layer must be firmly bonded, without delamination and bulging, and the steel mesh must be covered.