Traditional cast-in-place construction scheme

2 Calculation of lateral pressure of cast-in-place bent column (1) This project is a cast-in-place C30 bent structure, and the column section size is shown in figure 1. Because the construction joints can only be left on the surface of the support, the height of concrete pouring at one time is 6. 15 m, which will produce greater lateral pressure on the column formwork; (2) Because the load produced by fresh concrete on the column formwork is different from the gravity load of the platform formwork, the effect of fresh concrete pushing the side formwork horizontally outward is the same as that of water pressure pushing the container wall, but unlike water pressure, the concrete pressure is temporary. When the concrete is hard enough to support its own weight, the lateral pressure disappears immediately. Generally, concrete begins to harden after 1 ~ 2 h, and the lateral pressure on the formwork disappears immediately. The lateral pressure of formwork can be reduced by controlling the pouring speed of concrete. If the concrete pouring speed is too fast, the concrete has not yet begun to harden when pouring, and its horizontal pressure is close to the total head; When the concrete pouring speed is slow, before pouring the upper concrete, the concrete at the lower part of the formwork has already hardened, so the pressure will never reach the full head; Vibrating concrete with plug-in vibrator can temporarily liquefy all the concrete within its action radius, and then appropriately increase the horizontal lateral pressure; Adding retarder, fly ash or lowering the temperature can also delay the hardening of concrete, so the lateral pressure is increased.

3 template design

Installation of 4-column bent frame

Treatment of five column feet

6-column concrete pouring

7 effect analysis