Prevention and treatment of ceiling cracks in gyps

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Light steel keel gypsum board ceiling is widely used in various engineering ceilings because of its low cost, easy modeling, good fire resistance and easy construction team. When the gypsum board is fully painted with high-grade emulsion paint, there will be large or small cracks, especially on the large-area gypsum board ceiling. Although this crack does not affect the function, it affects its beauty. It is also listed as non rectification items in the project acceptance. How to prevent and control this crack? Now, from the perspective of construction, we talk about several problems that should be paid attention to and take corresponding technical measures:

first, false stress occurs in the lifting points and pendant nodes

this kind of situation is mainly due to the quality and technical reasons of construction personnel. There are several cases of such problems in the construction of light steel keel ceiling

1. The expansion bolts and nuts on the lifting parts and the screws and nuts that fix the crane are not paid attention to during the screw connection, resulting in the kink of the bolts and nuts and the damage of the screw threads

2. The lower part of the expansion screw is hung with a hanging bar, and the upper opening is not fixed with a fixing nut

3, ¢ 6, ¢ 8 hanging bars are used in many projects, especially at the end of the project, buy some disc reinforcement, and let the workers straighten it on site for hanging bars

4. The crane is connected with the main keel. Due to the deformation or non matching of the crane, the main keel is clamped in the middle of the crane and is not stressed at the bottom of the crane

5. The middle hanging is connected with the main keel, and the lower hanging is connected with the auxiliary keel, which leads to a movable gap between the main keel and the auxiliary keel

in the above cases, the leveled keel ceiling will become uneven under the action of external force, resulting in tension, deformation and cracks in the covered gypsum board. The solution to this problem is to pay attention to the construction of the structure and take some necessary measures. In case of such a situation, it is harmful and difficult to repair, so we must pay attention to it in the construction. The measures to solve such problems are:

(1). When tightening the bolts and nuts, tighten them along the threads, and do not damage the threads with strong force. (2) Before disc reinforcement is used as suspender, it must be qualified new reinforcement and can be used only after cold drawing or straightening. (3) The deformed parts in the main and auxiliary keel hangers and cranes must be processed with steel wire pliers during construction to meet the applicable requirements of the construction. Unsuitable or uncoordinated accessories may be discarded. (4) When hanging the auxiliary keel, be sure to keep the main and auxiliary keels close together. When the hanger is connected with the main keel, clamp it with a wire wrench to ensure that there is no movable gap in the connection.

Second, the selected position of the expansion bolt for fixing the hanging reinforcement is wrong, and the spacing does not match the modulus

this kind of situation mainly occurs on the porous YKB plate floor. When determining the spacing of the hanging reinforcement, the modulus size of the YKB plate, and some fixed points of the expansion screws fall in the YKB plate hole, At this time, the expansion head of the expansion bolt is in the hole and cannot be fixed, resulting in a movable gap between the top, bottom, left and right of the fixed point of the ceiling. This lifting point looks like a stress point. In fact, once it is stressed, it will deform. How to avoid this problem:

1. When snapping the fixed ink bucket line on the top plate, first find the intersection joint of YKB plate. Generally, this is the concrete pouring joint in civil construction, and this intersection joint is selected for the first line

2. The distance between lifting points is required to be 900--1200mm in the construction specification. During the specific construction, the distance between lifting points can be determined according to the width modulus of YKB plate within this range, which can not only avoid the occurrence of movable lifting points, but also avoid the interruption of YKB stress bars during electric hammer drilling, which will affect the stress of YKB plate. In case the fixed point falls into the YKB plate hole, there are two treatment methods: (1) re punch in the appropriate space around. (2) Use 50x50 iron plate with thickness of 3— 4mm nut tightening spot welding




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