As our country's prefabricated building industry gradually enters the stage of large-scale and mainstreamed development, in the future, how should construction enterprises do and what points should they pay attention to in order to further promote the development of prefabricated building industry?
Do a good prefabricated building and deepen the design
1. Master the key points of deepening design
(1) the detailed drawings of precast members should be drawn according to the requirements of various specialties, production and construction. When there is conflict in detail drawing, it is necessary to point out the need for improvement in time so that the design of prefabricated components can be modified in time.
(2) check the detail drawings of prefabricated components to ensure that they meet the specifications and installation requirements. The construction party should know the relevant national standards and specifications of Assembly type, in the deepening design, check whether the content and depth of detail drawings of prefabricated components meet the requirements of prefabricated components, engineering statistics and installation requirements.
2. Complete and deepen the design
(1) the practice of external wall decoration. When deepening the design of exterior wall decorative surface, we should pay attention to the layout details of face brick, decorative concrete, stone, etc. , at the same time, the purchase of stone should meet the requirements of aggregate strength and decorative beauty.
(2) the external wall energy-saving heat preservation structure. Thermal insulation structure should meet the functional requirements of the building, pay attention to the selection of thermal insulation materials and connector selection, to ensure accurate layout details. At the same time, the design performance should be verified to complete the design calculation verification process.
3. The production of prefabricated components should pay attention to the links
(1) production planning. The construction party shall participate in the design and adjustment of the production plan of the precast members according to the drawing requirements to ensure the steady operation of the production of the members.
(2) die design. The construction party shall ensure that the drawing design meets the needs of the construction, and according to the drawing, check whether there are any problems in the mold plan making, and propose the modification suggestions as soon as possible.
(3) people organization. Arrange the special person to control the quality of the components, ensure the strength is up to standard, the size is right and the appearance is right, and communicate construction requirements for the components.
(4) technical quality control measures. The component quality has great influence on the later assembly and installation, so we should pay attention to communicate with the component manufacturers in time. Component strength should be detected in time, not in line with the installation needs should be redone in time; size and the actual requirements vary too much, should also be timely contact manufacturers correct deviation.
(5) storage and transportation plan. On-the-go and reduce the transport distance is to ensure that the assembly of the construction site to save a strong guarantee.
Control the quality of projects in different prefabricated building
Fabricated wooden construction
1. store
(1) wood components should be stored in well-ventilated warehouses or rain-proof, well-ventilated places covered by the top. The components on the construction site should be classified according to the installation sequence, and the stacking should be arranged in the working area of the crane, and not affected by other working procedures.
(2) the corresponding measures should be taken to prevent the deformation of the assembly when the stack is laid down. Overlapping stacking, each layer of components between the pad block should be aligned, stacking layer number should be determined by the components, pad block bearing capacity.
(3) when stacking the backrest, the inclined angle between the backrest and the ground should be more than 80 ° .
(4) when stacking curve components, corresponding protective measures should be taken according to the shape of the components.
2. Install
(1) when the component is installed with temporary support, the distance between the support point of the precast column or wall and the bottom should not be greater than 2/3 of the height of the column or wall, and should not be less than 1/2 of the height of the column or wall.
(2) vertical component installation. Before installing the bottom component, compound the elevation of the base, and take corresponding moisture-proof measures, such as moisture-proof mat, before installing other components, should compound the axis position and elevation of the installed component.
(3) horizontal assembly installation. Two points should be adopted for Rod Assembly, and multi points should be adopted for long ones, and the deformation and out-of-plane stability should be checked for long ones.
Fabricated steel construction
1. store
The fire-proof ability of steel structure is very poor, and is greatly affected by temperature.
When the steel structure is heated between 100 ° C and 250 ° C, the tensile strength decreases and the plasticity increases with the increase of temperature
When the temperature reaches about 250 ° C, the tensile strength of the steel structure increases slightly, but the plasticity continues to decrease, resulting in“Blue-brittle phenomenon”
When the temperature exceeds 250 ° C, the steel structure will appear“Creep phenomenon”;
When the temperature reaches 500 ° C, the strength of steel structure is extremely low, which is easy to cause production damage, economic losses, and even casualties.
Therefore, the steel structure of the thermal insulation and fire design is extremely important, in storage must also pay attention to environmental temperature.
2. Install
(1) the information technology can be used in the integrated management of safety, quality, technology, construction schedule and so on. BIM technology can be used for virtual construction of structural components, building components and equipment pipelines.
(2) the influence of vertical compression deformation should be taken into account in the installation of high-rise steel structure, and the measures such as pre-adjusting the installation elevation and setting the connecting members should be taken according to the structural characteristics and influence degree.
(3) the precast exterior wall panel should be fixed permanently after axis, elevation and vertical dispatch check. When the slats are installed with double wallboards, the seams of the inner and outer wallboards should be staggered.
(4) points for attention in installation of keel partition system:
The top and bottom should be along the top keel and along the ground keel. Vertical should have vertical keel, in the position of the door frame should be strengthened keel;
Along the top keel, along the ground keel should be fixed according to the position of the elastic line, the fixed way can be used to shoot nails, expansion bolts, etc. , nail distance not more than 600 mm;
Against the wall, column vertical keel can be used to shoot nails, expansion bolts or wood screws and wall, column fixed, nail distance not more than 900 mm;
The middle vertical keel should be graded according to the width of the cover panel, with the width of not more than 1/2 plate and the width of the gap (generally 5mm) . The distance between them should not be more than 600mm. The two ends should be fixed by shooting nails. When the two dividing walls are connected longitudinally and transversely, the vertical keel of the joint part can not be omitted;
The transverse keel may be connected and fixed by a support card, a Catto and a connecting piece, and may be fixed with core-pulling rivets if necessary, but may not be welded. Transverse keel spacing should not be greater than 1200mm. Keels shall be provided at the seams of the cover panel.
Fabricated concrete structures
1. store
(1) the placement of composite floor slabs. The first layer of composite floor slab should be placed on h-section steel, ensure that the truss and section steel vertical, section steel 500 ~ 800 mm from the edge of the member. The layers are separated by four blocks of 100mm × 100mm × 250mm square wood, and the four square wood positions at four corners are placed parallel to the section steel. The number of storage layers does not exceed 8 layers and the height does not exceed 1.5 m.
(2) wall panel cube special shelf storage. The wallboard is stored in a cube-shaped shelf. When the width of the wallboard is less than 4 m, the lower part of the wallboard is cushioned with 2 pieces of 100 mm × 100 mm × 250 mm square wood, and each end is 30 mm away from the wall. When the width of the wallboard is larger than 4 m or with a hole in the door, three pieces of 100 mm × 100 mm × 250 mm square wood are placed on the bottom of the wallboard.
(3) stair storage. Stair storage should be placed in designated storage areas, storage area ground level should be guaranteed. Four blocks of 100mm × 100mm × 500mm square wood should be placed at the second and third step positions on the left and right ends of the folding ladder, and the distance between the front and the back sides should be 250mm.
(4) storage of beams. The first layer beam should be placed on h-beam, the length direction should be perpendicular to the section steel, the section steel should be 500 ~ 800mm apart from the edge of the member, and an h-beam should be placed at the middle distance of 4m when the length is too long, according to the length and weight of the member, the highest stack 2 layers. The layers are separated by square wood of 100mm × 100mm × 500mm to ensure the horizontal projection of square wood of each layer coincides with h-beam.
(5) column storage. The first layer of columns should be placed on h-section steel, the direction of the length should be perpendicular to the section steel, the section steel should be 500 ~ 800 mm apart from the edge of the member, when the length is too long, an h-section steel should be placed at the middle distance of 4 m, according to the length and weight of the member stacked up to 3 layers. The layers are separated by blocks of 100mm × 100mm × 500mm square wood to ensure that the horizontal projections of each layer square wood coincide with h-beam.
2. Install
(1) before placing precast members with reinforced sleeve grouting connection and reinforced mortar anchor lap connection, the following shall be checked:
Specification, position, quantity and depth of sleeve and reserve hole;
The specification, quantity, position and length of the reinforced bar to be connected, when there are sundries in the sleeve and the reserved mouth part, it should be cleaned;
When the connecting steel bar is inclined, it should be straightened;
The connection bar should not deviate more than 5mm from the center line of sleeve or hole.
(2) the thickness of multi-layer precast shear wall should not be more than 20mm when the bottom of the wall is made of grout.
(3) the environmental temperature should not be lower than 5 ° C during grouting construction, and when the curing temperature of the joint is lower than 10 ° C, the measures of heating and surrounding shall be taken.
(4) when installing prefabricated bending members, the length of the end should meet the design requirements, and the support block should be set between the end and the support member, the thickness of the support block should not be more than 20mm.
Do a good job of prefabricated building testing
Inspection of assembled wood structure
This item includes general provisions, materials, components, connection 4 items, clear material testing items should include physical properties, chord static bending strength, elastic modulus, etc.
The testing items should include dimension deviation, deformation, crack, anti-corrosion and anti-moth, termite, etc.
The connection detection should include bolt connection, tooth connection, mortise-and-tenon connection, bar-planting connection and metal connection, etc. .
Assembly steel structure inspection
This item includes general provisions, materials, components, connection 4 items, clear material testing including steel, welding materials and fasteners, such as mechanical properties, chemical composition of raw materials, steel Plate and fastener defects and damage, steel metallographic content;
The component detection should include the component size, structure, deviation and deformation and so on
The connection detection should include welding connection, Bolt Connection, Rivet Connection and so on.
Inspection of fabricated concrete structures
This item includes general provisions, materials, components, connection 4 items, clear material detection including precast members into the field of concrete, steel, field construction of post-cast concrete, steel, connecting material content;
The inspection of prefabricated members should include the defects, dimensional deviation and deformation, structural performance and so on
The detection of connection quality between structural members should include the position and size deviation of structural members, the quality of sleeve grouting and grout-anchor lapping grouting, the quality of welding connection and Bolt Connection, the quality of pre-cast shear wall bottom joint grouting, the quality of cast-in-place concrete in double-sided superimposed shear wall cavity, etc. .
Other system checks
(1) the detection of exterior envelope system includes general regulation, prefabricated exterior wall, exterior doors and windows, building curtain wall, roof and so on.
(2) the testing of equipment and piping system includes general requirements, water supply and drainage, heating, ventilation, air-conditioning and gas, electrical and intelligent.
(3) the testing of interior system includes general regulation, interior parts system, interior environment and so on.