Prefabricated concrete structures have already undergone explosive development in China. Due to the rapid development, there are inevitably some problems and hidden dangers in the construction process of prefabricated concrete structures..

(1) Prefabricated balconies are lifted using the four lifting rings reserved on the prefabricated panels;.

(2) During the lifting process of the balcony panel, pause 500mm away from the working surface, adjust the position, and then proceed with installation slowly;.

(3) After aligning the control line and placing the balcony panel, perform position adjustment to ensure horizontal placement, and finally adjust the elevation with a U-shaped bracket;.

(4) After the installation of the balcony hoisting, it is also necessary to calibrate it to ensure installation quality..

(5) When lifting laminated panels, modular lifting beams are used for lifting, and the lifting process is slow to ensure the stability of the laminated panels;.

(6) During the lifting process, pause briefly at a distance of 300mm from the working layer to adjust and position the direction of the laminated board; During the lifting process, avoid collisions, stop steadily and place slowly to ensure the integrity of the laminated board;.

(7) During installation, temporary brackets should be made at the bottom, with a spacing of 150cm between support points. 2-3 rows of brackets should be set for each bay;.

(8) If the construction of the structural layer is carried out, double-layer supports must be set up. After the completion of the construction of the first layer of laminated floor structure, the next support can only be removed when the strength of the cast-in-place concrete is greater than or equal to 70% of the design strength..

(9) In order to ensure that the replacement of suspension points on both sides of the steel wire rope during hoisting between different components consumes a lot of time, the suspension beam is set with two suspension points on one side, and the other side is set with component number suspension points according to the needs of the engineering components..

(10) The lifting of the wall panel adopts a modular lifting beam, and a reasonable lifting point is selected based on the position of the lifting ring of the prefabricated wall panel. The steel wire rope is connected to the reserved lifting ring of the outer wall panel with a shackle, and lifted to a distance of 500mm from the ground. The appearance quality of the components and the connection of the lifting ring are checked before continuing to lift..

(11) Before lifting, the lower side of the prefabricated wall panel needs to be nailed with 500mm wide multi layer panels, and the lifting requires slow and uniform speed to ensure that the edges of the prefabricated wall panel are not damaged..

(12) When lifting prefabricated wall panels, it is required that the tower crane slowly lifts to about 600mm above the working layer. The construction personnel use two sliding ropes to hook the panels with hooks, and use the sliding ropes to pull the panels and slowly lower the wall panels..

(13) The lifting of the bay window is connected by lifting ears, bolts, and reserved nuts on the bay window..

(14) After connecting, slowly move the bay window at a distance of 300mm from the working surface according to the position line. Wait until the bay window bolts are adjusted to the position of the through wall hole. Place the customized U-shaped bay window horizontal bite measure on the bay window, and use a sliding rope to pull the bay window to insert the bolts into the wall plate connection hole..

(15) Prepare prefabricated pedestals as required and pay attention to the reverse arch setting of the pedestals..

(16) Pour concrete normally, pay attention to vibration compaction, and apply isolation agent to the formwork..

(17) Wet curing is carried out when the concrete strength reaches 80%, and prestressed tensioning is carried out..

Rebar Cross Chair

(18) Tensioning should be carried out symmetrically, and stress controlled elongation values should be used for verification..

(19) Tensioning program: 0 → initial stress → over tensioning by 5% with a load of 2 minutes → anchoring..

(20) Timely grouting (usually cement slurry or cement mortar), with grouting pressure generally ranging from 0.5 to 0.7 MPa.