Hubei Wuhan Observation Pole Observation Pile Bridge Pier Body Settlement Observation Pole Sign Directly Buried Type

Description :

　　Bridges are composed of many structures, and the settlement observation methods, sign selection, and layout principles for each part are different after bridge construction. Therefore, when conducting bridge settlement observation, it is necessary to be familiar with the observation methods and key points of each part of the structure. Tiantong Pipe Industry will introduce the layout points of settlement observation targets for beams and culverts.

　　The methods of on-site pouring and prefabricated beams can be used for the beam body of the bridge, so the layout of settlement observation markers for the beam body is different:

　　1. For cast-in-place beams, settlement observation markers should be set up hole by hole for observation.

　　2. For prefabricated beams, generally only one observation mark needs to be set every 30 holes.

　　3. For beams constructed with mobile formwork, it is necessary to focus on observing the first 6 holes. After verifying the accuracy of the bracket arch, an observation mark can be set every 10 holes.

　　When observing the beam body, for beams with elastic camber greater than the design value, if there are beams that have not been observed before and after, settlement observation markers should be reset to observe the settlement of each hole, ensuring the stability and safety of the beam body.

　　For the settlement observation of culverts, observation markers should be set up for measurement. The settlement observation markers of culverts should be set on the side walls on both sides of the culvert, and signs should be set up at the entrance and exit of the culvert and the center of the culvert, with 6 signs set up for each. During the construction of the culvert and the filling stage, the measurement markers on the side walls can be moved to the cap stones.

　　Strengthening the construction process control of settlement observation markers

　　(1) Determination of cooling curve for settlement observation markers. The heating time of concrete hydration heat is very short, about 2-5 days after pouring. The elastic modulus of concrete is very low, basically in a plastic and elastoplastic state, and the constraint stress is very low. During the cooling stage, the elastic modulus rapidly increases, and the restrained tensile stress also increases over time. At a certain point, when the tensile strength is exceeded, a penetrating crack appears. In practice, it is safer to use the high temperature cooling curve in the middle of the section instead of the average cooling curve, and use the values in Table 1 to obtain an approximate solution. The basic conditions of Table 1 are: the cement type is slag cement; The cement grade is 425; The cement dosage is 275kg/m3; Steel formwork. When using other types of cement, with changes in grade, template, and cement dosage, multiply the above values by the following correction factor: tmax=t ×=k1 × k2 × k3 × k4. In the equation, k1, k2, k3, k4 are the correction factors.

　　(2) The settlement observation standard strictly controls the molding temperature on the concrete to be below 30 ℃.

　　(3) The settlement observation mark is embedded with cooling pipes, and a dedicated person is responsible for injecting cooling water into the cooling pipes during the initial setting of the concrete in batch * *. Through cooling and drainage, the heat inside the concrete is removed.

　　(4) When pouring concrete, the settlement observation mark is poured in a thin layer to control the uniform rise of the concrete during the pouring process and avoid excessive height differences caused by the accumulation of concrete mixtures. The layer thickness of the concrete is controlled at 20-30cm

　　(5) When the settlement observation target has a thick structure and a large amount of concrete is poured at once, layered pouring is used to increase the surface coefficient and facilitate internal heat dissipation of the concrete. The layer thickness is about 1.5m, and the interval between layers is between 5-14d.

　　(6) Strengthen the vibration of settlement observation markers in order to obtain dense concrete, improve compactness and tensile strength. After pouring, promptly remove surface water accumulation and conduct a plastering to prevent the occurrence of early shrinkage cracks.

　　(7) After pouring the settlement observation target concrete, a sunshade canopy should be erected to prevent the surface of the bearing platform from being exposed to sunlight.

　　(8) After pouring the settlement observation target concrete, the concrete surface is covered with a work cloth for insulation, and the settlement observation target is watered for curing to slowly cool and dry the silicon, reducing the temperature difference between the inside and outside of the concrete.

AfterSalesService :

• Hubei Wuhan Observation Standard