Assembled reinforced concrete floor refers to the prefabricated components in the factory or the construction site pre-made, and then transported to the site for installation of reinforced concrete floor. The length of the prefabricated panel is generally the same as the open space or depth of the room and is a multiple of 3M; the width of the panel is generally a multiple of 1 M; the cross-sectional dimensions of the panel shall be determined by structural calculation.
First, the type of board
Precast reinforced concrete floors are prestressed and non-prestressed two.
Precast reinforced concrete floor commonly used types are: solid plate, trough plate, hollow plate three.
1, solid plate
Features: simple production, construction convenience.
Disadvantages: poor sound insulation, poor water resistance.
Structural features: solid slab smaller specifications, the span is generally about 1.5m, not more than 2.5m, the thickness is generally 60mm-80mm or 1/30 of its span.
Support length: beam is not less than 80mm, the wall is not less than 100mm, the wall is not less than 120mm.
Use: Precast solid slab because of its small span, commonly used in aisle and small room, bathroom, kitchen floor.
2, trough board
Features: small weight, low cost, high carrying capacity, convenient hole, good thermal insulation.
Disadvantages: poor sound insulation.
Structural features: Grooved plate is a kind of prefabricated element combined with ribs, that is, there are side ribs on both sides of the solid plate, the load on the plate is borne by the side ribs, the plate width is 500 ~ 1200mm, Strain channel board length is usually 3 ~ 6m. Plate rib height of 120 ~ 240mm, thickness of only 30mm.
Shelving methods: is set (plate rib downward) more reasonable stress, the bottom of the ceiling to do long.
Inverted (rib upward) to solve the sound insulation, thermal insulation problems, roof flat, suitable for more rooms in the pipeline.
3, hollow board
Features: Up and down flat, the middle of the hollow, save material, sound insulation performance is good.
Disadvantages: the board can not easily hole.
Construction features: holes are round, oval, square, rectangular, board width of 400,500,600,800mm and other dimensions, board span can reach 6.0,6.6.7.2m, the thickness of the board is 120 ~ 300mm
Use: The previous project is widely used.
Second, the structure of the plate layout
1, the layout of the board when the type of type the less the better;
2, to avoid the phenomenon of trilateral support;
3, the heart board before installation, should be in the board side of the hole filled with C15 concrete short column (ie plug) to avoid crushed board end.
Third, the board's shelving requirements
When it is supported on the beam, its resting length shall not be less than 80mm;
When it is supported on the inner wall, its resting length shall not be less than l00mm;
When it is supported on the external wall, its resting length should not be less than 120mm.
Before decking, first leveled the wall or beam with M10 cement mortar 10 ~ 20mm thick (ie, sit), and then plank to make the board and the wall or beam have a better connection, but also to force the wall evenly.
When using the beam plate structure, the plate on the beam shelves in general there are two ways, one is the board directly resting on the top of the beam; the other is the board resting on the basket beam or cross beam [board in the beam on the shelving the way].
Fourth, the slab processing (60mm-200mm)
Prefabricated slats play the role of connecting two adjacent panels to work together to make the floor as a whole. In the specific layout of the floor, often appear gap.
① When the gap is less than 60mm, the adjustable plate joints (to ≤ 30, filling C20 fine stone concrete);
② When the gap between 60 ~ 120mm, can be poured in the concrete joints with 2φ6 long steel reinforcement;
③ When the gap between 120 ~ 200mm, set the cast-in-place reinforced concrete slab, and the plate is located in the wall or have wear tube parts;
④ When the gap is greater than 200mm, can be adjusted directly, but also adjust the size of the board [such as the plate seam].
Fifth, anti-seismic assembly of reinforced concrete floor structure
Ring beam should be close to the bottom of the prefabricated floor plate set, the outer wall should be set up Notched ring beam (L-beam), the prefabricated plate hoop in the ring beam. When the span of the plate is more than 4.8m and parallel with the external wall, the prefabricated plate edge of the external wall should be provided with tension bars and ring beams.