We have already known about different forms of vibration techniques for concrete. In this post we will discuss about a special type of vibrator that is applied externally to concrete i.e. not applied directly to concrete.
First we will learn where it is used. This type of vibrator is suitable for casting concrete in thin walls, columns and in construction of precast units. Clamps are used to attach the machine to the formwork externally. The aim is to provide vibration to concrete near shutters. The congestion in penetrating vibrator head require such machine and in thin sections where only surface vibration provides full vibration to concrete.
The congestion situations includes where lateral ties, spacers and regular longitudinal reinforcement produce a impossible condition to provide usual internal vibration to concrete. This formwork vibration produce a excellent finishing surface of concrete. But it is not economical and efficient. The vibration is provided indirectly to concrete consuming more power as compared to internal vibrator. Thus efficiency of formwork vibrator is considerably less than usual internal vibrator.