The choice of waterstop type depends on the anticipated joint movement:
Plain Dumb-bell Type: This design is ideal for construction joints where minimal movement is expected. Its simple shape effectively seals the joint against water infiltration while accommodating slight expansion or contraction.
Center-bulb Type: This type is better suited for expansion joints or locations prone to lateral and shear movements caused by settlement or deflection. The center bulb provides additional flexibility, allowing the waterstop to adjust to these movements while maintaining a watertight seal.
As described in W. L. Monks’ 1972 work, understanding the specific requirements of each joint and selecting the appropriate waterstop type is crucial for ensuring the long-term watertightness and durability of concrete structures.