by 1.
On site and off site preparation The construction site shall be well prepared for “three supplies and one leveling”, road access, water supply, power supply and leveling, and the site shall be well prepared for temporary facilities and PC structure storage; In order to meet the construction requirements of PC structure construction and the maximum weight of individual PC structure components, ensure that the hoisting distance of PC structure of each house is met, and according to the construction progress and site layout requirements, 4 STC7015 tower cranes are provided for buildings 1 # to 4 # of the project, which are reasonably arranged near each house, to ensure that the nodes of each floor are hoisted every 5 to 6 days on average.
2.
Prepare PC prefabricated prefabricated components off-site and carry out factory production to select professional prefabricated component manufacturers; Fabricated prefabricated components shall be transported to the construction site for hoisting and installation by the general contractor after being processed in the factory.
Transportation In order for the PC structure to enter the construction site and be able to transport smoothly at the construction site, the main gate road to the site shall be at least 8m wide, and the road to the construction site shall be 5m wide, so as to ensure that the PC structure transport vehicles can pass through the main gate road in both directions, and ensure the smooth turning, straight walking and other ways at the construction site.
3.
When transporting prefabricated components, the vehicle shall start slowly, the speed shall be uniform, and the vehicle shall slow down when turning and changing lanes to prevent the wallboard from overturning.
The PC structure of this project is characterized by a large number of single layers and heavy weight.
The drawing shows that the PC structure of each room is about 4m long at most and about 4.6t in weight.
According to the above construction requirements and the convenience of PC structure hoisting, the PC structure management team plans to set up a PC storage yard for each room.
The storage yard is the basement roof (with fire lane and reinforcement measures at the bottom).
The rest of the surrounding construction roads of the basement are made of 200 thick C20 concrete, and the trunk road and PC storage yard on the non basement must be paved Φ 18@150 Single layer two-way reinforcement.
The reinforcement transport vehicle and PC storage yard must use the basement top shift as the construction road and material storage yard.
According to the requirements and actual conditions, the roof of the basement within the scope of the vehicle road and PC storage yard shall be reinforced.
In particular, the vehicle line shall be reinforced with steel pipes.
All bent steel pipes shall be removed after the structure is capped.
The wallboard shall be placed vertically, and the support meeting the rigidity requirements shall be made of channel steel.
The supporting points of the wallboard shall be set at both ends of the bottom of the wallboard, and the stacking site must be flat and solid.
Flexible materials can be used for supporting points, which shall be temporarily fixed after stacking, and temporary enclosure measures shall be taken for the site.
Due to man-made collision or tower crane mechanical collision and toppling, the PC in the yard collapsed in the form of Donomi domino.
The yard is stacked in staggered order according to the hoisting sequence, with a certain interval between plates.
As shown in the following figure, the finished product protection measures must be paid attention to during the transportation, stacking and hoisting of the PC structure of this project.
Steel frame is used for auxiliary transportation during transportation.
When transporting wallboards, the car starts slowly and the speed should be uniform.
When turning and changing lanes, it should slow down to prevent wallboards from overturning.
Due to the heavy construction of the PC in this project, it is difficult to protect the yard and transport finished products.
Cotton yarn or rubber blocks are used at the junction of PC structure and steel frame to ensure that the PC structure and steel frame are damaged due to collision during transportation.
In the process of stacking, the PC structure shall be kept in balance by steel carrying pole during the hoisting process, and shall be kept stable and handled with care.
Before being handled with care, cotton yarn, rubber blocks or sleepers shall also be placed at the location where the PC structure is stacked to keep the lower part of the PC structure flexible; Stairs, balconies and other PC structures must be stacked in single pieces.
When stacking, four wood blocks with uniform size shall be used for padding.
The height of the wood blocks must be greater than the height of the exposed stirrup bars and corners of the laminated plate to avoid damage to the PC structure.
At the same time, cotton yarn or rubber blocks shall be properly placed on the padding to keep the lower part of the PC structure as a flexible structure.
In the process of hoisting construction, pay more attention to the method of finished product protection.
On the premise of ensuring safety, the PC structure should be lifted and placed gently.
At the same time, before installation, the plastic gasket should be placed at the fine adjustment position of the PC structure.
The plastic gasket is a flexible structure, which can effectively reduce the damage of the PC structure.
During construction, PC structures such as stairs and balconies shall be covered with wooden boards for protection.
Before pouring, the sleeve connecting anchor rebar is protected by finished PVC pipe to prevent contamination of the connecting rebar during concrete pouring and tamping, which will affect the later PC hoisting construction.
3.
On site construction of PC structure 4.
Hoisting scheme of prefabricated components 4.2.1 Hoisting process of prefabricated walls 4.2.2 Preparations before hoisting prefabricated external walls 4.2.3 Before hoisting prefabricated external walls, the quality director shall check the model and size of wallboards, and after checking the quality, a specially assigned person shall be responsible for the hook.
When the hook hanging personnel evacuate to a safe area, the following signalman shall confirm the safety around the components, and after confirming the correctness, carry out trial hoisting, and command the slow hoisting, When the crane is lifted to about 0.5m above the ground, the tower crane lifting device shall continue to lift after confirming the safety.
When the wall is lowered to 0.5m from the floor, fine tune it according to the pre positioned guide frame and control line, and then slow down the lowering.
Two professional operators will guide the landing with their hands.
When the landing reaches 100mm, one worker will use a special visual lens to observe whether the connecting reinforcement is aligned with the hole.
4.2.5 Installation of prefabricated exterior wall (the lifting personnel on the working face shall adjust the location line and elevation control line of the component and the position of the embedded reinforcement in advance, prepare the sizing block, place the component in the control line, and place the sizing block) Method 2: Record the elevation a value and the average elevation b value of each point clearly.
After the corresponding prefabricated exterior wall enters the site, the height c value of the inner leaf wall at the corresponding gasket position can be obtained after acceptance, Then, according to the equation calculation based on the storey height of 2900mm, the height d of the spacer can be obtained..
