Six Temporary Consolidation Forms of Pier and Beam in Cantilever Casting Continuous Beam
Release Time： 2022-08-18 11:16
There are six common forms of temporary consolidation of cantilevered continuous beams, piers and beams. They are introduced as follows:
The first type: pier beam consolidation consisting of pre-embedded steel bars at the top of the pier and temporary consolidation pads of sulfur mortar. The advantages are that the structure is simple, the construction is more convenient, and the beam body is relatively stable and safe during the construction process. The disadvantage is that the electrolytic resistor is prone to failure, and the temporary support often cannot be completely melted.
The second type: the pier beams composed of pre-embedded steel bars and sand cylinders on the top of the pier are consolidated. The advantage is that the consolidation of the pier beam is relatively stable and the removal is convenient. The disadvantage is that the sand tube has a small settlement when it bears the weight of the beam body and the construction load, the selected sand tube is unevenly stressed, the sand tube production is more complicated, and the material is wasted.
The third type: the concrete-filled steel tubular column and the pier beam composed of the pre-embedded steel bars in the concrete column are consolidated. The embedded steel bar is welded, the concrete is poured in the pipe, and the embedded steel bar on the upper part of the steel pipe is connected with the beam body. The advantage is that it can be suitable for longer 0# blocks and can simplify the erection of 0# block brackets. It can bear unbalanced loads and is easy to dismantle. The disadvantage is that the contact surface between the upper opening of the CFST column and the beam body is inclined, and there is a slight slip between the two when the load is applied.
The fourth type: vertical prestressed steel bars and steel pipes are combined to form a pier beam consolidation. A steel pipe with a diameter of 80cm is used to set it at 20cm from the edge of the platform. There are 4 steel pipes on each side of the pier body, the steel pipes are inclined, and 2 bundles of vertical temporary anchoring prestressed steel bars are installed in each steel pipe. pull. The advantage is that the steel pipe is used as the 0# block support, which simplifies the support and facilitates removal. The disadvantage is that the steel pipes are inclined, and the top surface of the same row of steel pipes is difficult to control in a straight line, resulting in uneven stress on the steel pipes and slightly poor stability.
The fifth type: The piers and beams are connected by concrete piers around them. Reinforcing bars are arranged in the concrete buttresses, and a 5mm-thick layer plate is placed between the concrete buttresses and the top surface of the pier and the bottom surface of the continuous beam to separate the concrete of the buttress from the concrete of the bridge pier, so that the concrete surface of the top of the pier is flat when the buttress is removed. Therefore, the concrete piers play the role of support, while the steel bars or finished threaded steel bars mainly play the role of tension. The continuous beam and the bridge pier are connected as a whole through the buttresses around the pier top, that is, consolidated into a whole, so that the continuous beam is stable during the suspension casting process. After the continuous beams are closed, the temporary buttresses can be removed. The concrete of the temporarily consolidated buttresses is removed by blasting or chiseling, and the steel bars in the buttresses are cut and removed by cutting machines. The Liji Bridge of the 12th bid section of the subgrade project of Liuwu Expressway and the Banzhuyuan Bridge of Hewu Expressway adopt this consolidation form. This consolidation form is the most commonly used temporary consolidation form at present.
The sixth type: set up temporary buttresses (temporary piers) outside the main piers to support and consolidate them to form a whole with the piers. This method can be used when the pier height is low. Few examples are used.
(Note: There are two ways to connect the continuous beam and the pier. One is that the continuous beam transfers the weight of the upper structure of the bridge to the lower structure of the bridge through the bridge bearing; the other is that the continuous beam and the pier are poured as a whole, that is Generally speaking, the rigid connection. For example, the connection between the upper structure and the lower structure of the main pier of the main span of the Baishuihe Bridge on the Liuwu Expressway constructed by our company is a rigid connection. The connection between the auxiliary span and the bridge pier is still connected by the bridge bearing.< /p>