Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
Most of the steel structure roofs use profiled color steel plates, so I mainly take profiled color steel plates as the research object.
Steel structure roofs, walls and other enclosure structures generally use profiled color steel plates. The advantages of single-layer color steel plates are light weight, high strength, easy production and installation, large plant space and low price; the disadvantage is the thermal conductivity and thermal conductivity of steel plates. The coefficient of expansion and contraction is large, and the sound insulation effect is poor, so that the steel plate is corroded and rusted by rainwater, resulting in water leakage. For buildings that require thermal insulation, heat insulation and sound insulation, double-layered color steel plates can be filled with thermal insulation materials (such as glass wool, rock wool, polystyrene foam, etc.); The pre-composite forming of color steel plate factory (called color steel sandwich panel).
At present, the lap joints of profiled color steel plates basically include long lap joints, lateral lap joints, roof ridge joints, gutter joints, and wall joints and other special skylights, exhaust holes, drains, and anchor joints. There is generally no possibility of water leakage in the profiled color steel plate itself. Therefore, the main reasons for water leakage of color steel profiled plates are lap joints, joints, rust, etc.
The project of Area B of the Second Teaching Building of the South Campus of Civil Aviation College is a teaching and experimental office building with a total construction area of 10961m2. The main body of the project has five floors and a building height of 22.36m. The main body is a cast-in-place reinforced concrete frame structure, and the frame filling wall is generally made of slag concrete blocks. Part of the outer eaves of this project is a glass curtain wall, and the awning is covered with aluminum-plastic panels. The roof is a colored metal composite thermal insulation board roof, and part of it is a shangren roof. The roof area of this project is about 2500m2, the steel beams are welded H-shaped steel beams, and the roof is double-layered color steel plate filled with glass wool. The material of the main steel components is Q235. The purlins are made of Q235 C-type thin-walled steel.
The first is the lap joint. The reason for the water leakage here is that the key to solving the water leakage is that the construction is not in accordance with the specifications. Therefore, in order to prevent the occurrence of the above problems, we have made a complete construction plan before construction. When installing each steel plate, the edge should be lapped accurately on the previous steel plate, and clamped with the previous steel plate until the steel plate is installed. both ends are fixed. A simple and effective method is to use a pair of vices to clamp the overlapped steel plates separately. The step of installing the steel plate in place and lapped with the previous steel plate.
The steel plate is in place along the longitudinal direction, and its ends, especially the upper end, need to be clamped with pliers to clamp the lap portion, so as to ensure that one end of the steel plate is in place, and the lap joint at one end is also in the correct position, thereby fixing the steel plate. During the process, the splint pliers should always clamp the steel plate longitudinally. After the two plates are overlapped, a penetrating fixation can be used, that is, a self-tapping self-drilling screw is driven into the overlap. The self-tapping and self-drilling screws should also be waterproofed with waterproof caps and waterproof rubber pads.
This is done so that the important work procedure of color board lap during construction can be completed well. Strictly following this requirement in the construction can not only prevent rain leakage at the lap joint, but also solve the rain leakage caused by the rust and corrosion of the color plate.
The second is that the color plate roof at the node has many styles according to the different nodes of the structure, but it can be generally summarized as follows: gutter, roof ridge, cornice, gable and the node out of the roof.
The nodes that are prone to rain leakage in our projects are: ① gutter node, ② cornice height span node, ③ gable node. In order to solve the waterproof treatment at the above-mentioned nodes, we design and construct the above-mentioned nodes based on the general joint practice and combined with the design requirements of this project.
1.Gutter node. The reasons for the rain leakage here are: ①The design is unreasonable, which causes the water to reverse. ②The construction was not done in accordance with the specifications, resulting in rain leakage.
There are two general forms of gutters:
One is the outer gutter, and the other is the inner gutter. The reason for the leakage of rain in the gutter is that there are defects in the welds in the gutter and holes, which cause rain leakage, or the anti-corrosion in the gutter is not done well, causing the steel plate to corrode and leak. Therefore, in the construction of the gutter, the welding seam must meet the requirements of the specification. After checking the welding seam grid, apply two layers of red dan and then add two layers of anti-corrosion paint. Only in this way can the gutter be leak-proof.
The gutter of this structure is made of 3mm steel plate rolled in sections, each section is 2m, and the two ends are welded with welding rods. After welding, the inside and outside of the gutter should be painted with anti-rust paint, and then the insulating grease should be applied twice for waterproofing in it, and then the closed water test should be done. After the verification is qualified, the aluminum composite panel is installed.
2.High and low span cornice nodes. The reasons for the rain leakage here are: ① The design is unreasonable and the slope is too small. ②The corners are not tightly sealed or glued. The most likely place for rain leakage at this node is the intersection of the rock wool sandwich panel and the low span. Here, attention should be paid to the slope of the low span so that no water can accumulate here. The connection between the rock wool sandwich panel and the inner side of the wall panel is covered with water. The upper and lower parts of the angle aluminum should be covered with sealant. This can not only prevent the infiltration of rainwater from the rock wool sandwich panel, but also prevent the infiltration of water from the low-span color plate into the angle aluminum when the rain is heavy.
3.Gable nodes. The main reason for the rain leakage in this place is that the place where the roof color board contacts the gable wall is not handled properly, causing water to flow into the house along the gable wall. This node is the intersection of the roof of Zone II and the gable of Zone I (III), and there are expansion joints here, which caused a lot of trouble for our construction. To this end, we set up a special research group and after studying a lot of data, we finally decided to open a 60×40 arc groove at the gable 240mm above the roof of Zone II, and then embed the top of the color steel water-covered arc cover into the groove. The rivets are fastened and the ointment is applied. In this way, rainwater will not infiltrate from the gable, and even if the expansion joint has a certain expansion color steel flashing arc cover in the future, it can withstand it.
The roofing project has been constructed in accordance with the above design, and has experienced three heavy rains so far. So far, the roof drainage has been smooth and there is no rain leakage, which has initially achieved the expected goal. My theoretical knowledge and practical experience have been greatly improved through the research, design and practice of the waterproofing of roof color panels in this project. The roof waterproofing of steel structures is a worldwide problem. I only start from this project, and both theoretical research and practice have certain limitations. In the future, there will be more and more steel structure building styles, and the joint forms will become more and more complex, which brings greater challenges to our design and construction. For this reason, we will not be limited to this, and should conduct more in-depth research on the roof waterproofing of steel structures in the future.
