by Source: teaching outline of prefabricated architecture, loading, unloading and stacking of components; Lifting, installation, positioning and correction of components; Component transportation safety management and finished product protection.
Loading, unloading and stacking} methods of components 1.
Low flat cars should be used for the transportation of prefabricated components.
Special racks should be set on the cars, and reliable measures should be taken to stabilize components.
The precast component can be transported only when the concrete strength reaches the design strength.
The prefabricated exterior wall panels should be transported vertically.
The prefabricated laminated floor slab, prefabricated balcony slab and prefabricated stairs can be transported horizontally, and the support pad position shall be correctly selected.
2.
After the prefabricated components are transported to the construction site, storage yards shall be set respectively according to the specification, variety, used parts and hoisting sequence.
The on-site barge storage yard shall be set within the working range of the crane, and channels shall be set between the stacks.
3.
The on-site transportation road and stacking yard shall be flat and solid, and drainage measures shall be taken.
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 direction of unloading and hoisting, and there shall be a site to meet the turnover of prefabricated components.
4.
The prefabricated laminated floor slab can be stacked, and the layers shall be leveled and padded, the support pads of each layer shall be aligned up and down, and the support pads of the lowest layer shall be usually set.
The number of stacked layers shall not be greater than 6.
The prefabricated exterior wall panels at key points can be inserted or placed against each other.
The stacking frame shall have sufficient stiffness and shall be firmly supported.
The adjacent stacking racks should be connected as a whole.
The prefabricated exterior wall panels should face outward, and the weak parts such as waterstop, highland opening and wall corner should be connected.
Shaped protection cushion blocks or special accessories should be used for strengthening protection.
Component lifting, installation, positioning and correction I.
component lifting} methods before construction, classify and count all prefabricated components, calculate the most reconstructed parts, 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 hoisting site conditions of prefabricated components.
The radius of gyration shall cover the hoisting area and facilitate installation and disassembly.
The lifting points of key points during the lifting of prefabricated components shall be reasonable and coincide with the center of gravity of the components.
Adjustable horizontal lifting beams should be used to lift the components in place evenly to ensure that the components 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 against the edges and corners of the components.
After the components are lifted stably, move the boom at a uniform speed, and align it in place manually when it is close to the building.
▲ hoisting with adjustable cross beam ▲ hoisting with embedded lifting rings.
Before hoisting, the control dimensions such as centerline and elevation shall be marked on the components and corresponding supporting structures according to the design requirements, and the embedded parts and connecting reinforcement shall be checked and marked according to the design requirements.
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 member shall not be less than 45 °.
When lifting with a hanger, it shall be determined by experience.
2、 Component positioning} method: the operation mode of slow lifting, fast lifting and slow placing shall be adopted for the hoisting of prefabricated components.
The prefabricated exterior wall panels should be installed from top to bottom to ensure the stable placement of components.
The operation mode of “hoisting – positioning – preliminary correction – fine adjustment” can be adopted for the hoisting and correction of prefabricated components.
The prefabricated exterior wall panels hoisted in advance shall be provided with temporary supports with the floor during installation.
Key points 1 When the component is lifted off the ground, such as the top (surface) if it does not reach the level, it must be lifted to the place where the components are in place after adjusting the level, so as to facilitate the alignment of reinforcement and the placement of components.
2.
After the column formwork is removed, the reinforcement position shall be rechecked and adjusted immediately to ensure that it will not conflict with the beam reinforcement and avoid the beam being unable to be in place.
3.
If the height of the lifting point of the protruding window, balcony, staircase and some beam components is the same as the component, the lifting point at the lower part shall be the same It can be pulled and hoisted, hoisted and levelled.
When using the gourd, the height should be adjusted tightly.
4.
Before beam hoisting, one 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 before beam and wall hoisting.
Otherwise, the quality of column core area cannot be guaranteed.
5.
Before beam hoisting, all beam bottom elevations shall be counted, and the construction shall be arranged according to the beam hoisting scheme of crossing parts from low to high.
6.
The beam reinforcement can be bound only after the wall is hoisted, otherwise the wall anchor reinforcement will be prevented from penetrating into the beam.
7.
If the wall is loaded horizontally, the lifting appliance shall be installed on the wall first, and then the lifting appliance shall be moved to the wall top after the wall is lifted horizontally to the ground.
Pave tires or rubber pads at the bottom of the wall and turn the wall to make it vertical, so as to avoid damage to the corners at the bottom of the wall.
3、 Component correction} method: external wall panel correction: the elevation of the external wall panel shall be controlled by the bolt elevation on the connector.
The bolt top elevation shall be measured and corrected before the external wall panel is hoisted, and the external wall panel shall be placed in place at one time.
Connect the embedded bolts on the outer wall panel with a wire tensioner to control the front and rear of the outer wall panel in place; Adjust the bolts on the connectors to control the perpendicularity of the wallboard.
At the same time, the edge line of the exterior wall panel is aligned with the floor to control the “left and right” size; Connect the connector with the bolt hole embedded in the external hanging plate, support the connector on the column with a jack, and adjust the left and right positions of the external hanging plate in place.
Floor slab Balcony slab correction: after it is basically in place, use chain block and crowbar to fine tune the floor slab (balcony slab) until the position is correct and the laying is flat.
The verification of the side center line of the prefabricated exterior wall slab and the verticality of the layout at the key points shall be mainly based on the bus.
When correcting up and down, the adjustment shall be based on the vertical joint.
The joint of the prefabricated exterior wall slab shall mainly meet the flatness of the outer wall.
When the inner wall is uneven or warped, it can be adjusted in the inner decoration or the inner insulation layer.
The external corner of the gable and The correction of adjacent plates shall be adjusted based on the external angle.
The check of the joint flatness of precast exterior wall panels shall be adjusted based on the floor horizontal line.
4、 The temporary adjusting rod and limiter connected with the prefabricated exterior wall panel shall be removed after the concrete strength meets the design requirements..
