Formwork for bridge pier column
Nowadays, Obround, elongated hexagonal shapes are preferred over conventional pier columns shapes for aesthetic reasons. Therefore, the fabrication of formwork become a bit harder and required excellent workmanship. Different types of formwork available at the market. Steel formwork and wood formwork are used extensively.
Steel formwork: steel formwork is made of small pieces of steel formwork. These pieces are connected using bolts to form the shape of the pier column. Therefore, it is easy to lift and install. Furthermore using well-fabricated steel formwork will produce concrete with a smooth surface.
The main component of the steel shutter
1. Mold: in steel shutter mold are made from small pieces. These pieces are connected through bolts to form the required shape.
2. Tie road: Tie road will be fixed in both directions. Tie rods will resist concrete pressure and prevent the shutter from opening. Spacing and numbers of tie road will be determined by the designer depends on loads from concrete and strength of tie road.
3. Wingnuts: used to retrain and secure tie road against any movement. It should be adequately fastened before concreting.
4. Soldier: in some steel formwork soldiers are used. Tie roads are anchored to the soldier so the load will be distributed evenly and to avoid concentration of pressure at anchorage area of tie road. Figure no:2 showing a soldier.
5. Jacks: The main function of jacks is to support the formwork against any movement. Also, it will be used to align the formwork.
Wood formwork: wood formwork usually fabricated at construction field. The fabrication is easy but required competent persons. Also, it is time-consuming. Wood formwork is made using timer and layers of plywood. As a result, the thickness and weight of wood formwork are more than steel shutter. Therefore, handling of wood formwork is a bit harder than a steel shutter. The inner surface of formwork can be textured with GRP to ensure smooth concrete finishing. The supporting system is similar to steel formwork.