by Source: loading, unloading and stacking of prefabricated building teaching outline components; Lifting, installation, positioning and correction of components; Component transportation safety management and finished product protection.
Loading, unloading and stacking of components: 1.
Prefabricated components should be transported by low flat truck with special frame and reliable measures for stabilizing components.
The prefabricated components can be transported only when the concrete strength reaches the design strength.
Prefabricated exterior wall panels should be transported vertically.
Prefabricated laminated floor slabs, prefabricated balcony slabs and prefabricated stairs can be transported horizontally, and the support pad position should be correctly selected.
2.
After the prefabricated components are transported to the construction site, the storage yard shall be set up according to the specifications, types, parts used and lifting sequence.
The site lightering yard shall be set within the working range of the crane, and the passage shall be set between the stacks.
3.
The site transportation road and storage yard should be flat and solid, and have drainage measures.
The road for transportation vehicles to enter the construction site shall meet the transportation requirements of prefabricated components.
There shall be no obstacles in the unloading and lifting work direction, and there shall be a site for the turnover of prefabricated components.
4.
Prefabricated laminated floor slab can be stacked.
The layers should be leveled and compacted.
The support pads of each layer should be aligned up and down, and the bottom layer should be normally set.
The number of stacked layers shall not be greater than 6.
Prefabricated exterior wall panels at key points can be placed by inserting or leaning, and the stacking frame shall have sufficient rigidity and shall be supported firmly.
The adjacent stacking frames should be connected as a whole.
The prefabricated outer wall panels should face outward, and the weak parts such as waterstops, high ground openings, and wall corners should be connected.
The shaped protective pads or special accessories should be used to strengthen the protection.
Component lifting, installation, positioning and correction I.
Component lifting method Before construction, classify and count all prefabricated components, calculate the most reconstructed components, and select corresponding lifting facilities on this basis.
Before the hoisting of prefabricated components, the mechanical model and supporting slings shall be determined according to the weight, shape, installation height and site conditions of prefabricated components.
The radius of rotation shall cover the hoisting area and facilitate the installation and disassembly.
The lifting point of the prefabricated component at the key point shall reasonably coincide with the center of gravity of the component, and the adjustable transverse lifting beam should be used for balanced lifting to ensure that the component can be lifted horizontally.
Standard slings should be used for prefabricated components, and the slings can be in the form of embedded lifting rings or embedded connecting steel sleeves.
Avoid bumping the edges and corners of the components.
After the components are lifted stably, move the lifting arm at a constant speed.
After the components are close to the building, manually align them in place.
▲ Use adjustable transverse lifting beam for hoisting ▲ Before using embedded lifting ring for hoisting prefabricated components, mark the control dimensions such as centerline and elevation on the components and corresponding supporting structures according to the design requirements, check the embedded parts and connecting reinforcement according to the design requirements, and make marks.
Prefabricated components shall be hoisted according to standard drawings or design requirements.
When lifting, the included angle between the rope and the horizontal plane of the component should not be less than 45 °.
When lifting with a hanger, it should be determined by experience.
2、 The prefabricated components shall be hoisted slowly, rapidly and slowly.
The prefabricated exterior wall panels shall be installed from top to bottom to ensure the stable placement of the components.
Prefabricated components can be hoisted and calibrated in the way of “hoisting – positioning – preliminary correction – fine adjustment”.
The prefabricated exterior wall panels that are hoisted first shall be provided with temporary supports at the same time as the floors.
Key point 1.
If the top (surface) of the component does not reach the level when it is lifted off the ground, it must be adjusted and then lifted to the position of the component, so as to facilitate the reinforcement alignment and component placement.
2.
The position of reinforcement shall be rechecked and adjusted immediately after the column formwork is removed to ensure that it will not conflict with the beam reinforcement and prevent the beam from being unable to place.
3.
The height of the lifting points on the same component, such as projecting windows, balconies, stairs and some beam members, is different.
The lifting points at the lower part are connected by a hoist.
After lifting, they are leveled.
When falling, the hoist is used to closely adjust the elevation.
4.
Before beam hoisting, a column stirrup shall be installed in the core area of the column, and two column stirrups shall be installed after the beam is in place, and then the beam and wall can be hoisted.
Otherwise, the quality of column core area cannot be guaranteed.
5.
Before lifting the beam, the elevation of all beam bottom shall be counted, and the lifting scheme of the cross part of the beam shall be arranged according to the low before the high.
6.
The beam surface reinforcement can be bound only after the wall is hoisted, otherwise the wall anchoring reinforcement will be prevented from penetrating into the beam.
7.
If the wall is horizontally loaded, the lifting appliance shall be installed on the wall first, and then the lifting appliance shall be moved to the top of the wall after the wall is horizontally lifted to the ground.
Lay tires or rubber pads at the bottom of the wall, and turn the wall over to make it vertical, so as to avoid damage to the corners at the bottom of the wall.
3、 Component calibration method: the elevation of the outer wall panel shall be controlled by the bolt elevation on the connector.
Before the outer wall panel is hoisted, the bolt top elevation shall be calibrated by measurement, and the outer wall panel shall be placed in place once.
Connect the embedded bolts on the outer wall panel with the wire tightener to control the front and rear of the outer wall panel in place; Adjust the bolts on the connector to control the verticality of the wallboard.
At the same time, the side line of the outer wall plate shall be aligned with the floor to control the “left and right” size; Connect the connector with the bolt hole embedded in the external hanging plate, and support the connector on the column with a jack to adjust the left and right positions of the external hanging plate.
Calibration of floor slab and balcony slab: after the floor slab is basically in place, use chain block and crowbar to fine tune the floor slab (balcony slab) until the position is correct and it is laid flat.
The check of the side center line and layout perpendicularity of the prefabricated exterior wall panel at key points shall be adjusted mainly by bus.
The vertical joint shall be used for adjustment during up-down correction.
The joints of prefabricated exterior wall panels shall mainly meet the flatness of the exterior wall.
When the interior wall is uneven or warped, it can be adjusted in the interior decoration or the interior insulation layer.
The external angle of the gable and the adjacent plate shall be adjusted based on the external angle.
The check of the joint flatness of the prefabricated outer wall panel shall be adjusted according to the horizontal line of the floor.
4、 The temporary adjusting rod and stopper connected with the prefabricated outer wall plate in the method of component positioning shall not be removed until the concrete strength meets the design requirements.
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