TOWARDS BETTER JOINTS: THE PARAPET AND KERB TREATMENT

This article discusses some performance criteria and properties for joint assemblies in bridges, with special reference to the parapet and kerb treatment. The performance of a joint assembly can be affected adversely by several conditions that may be identified through the process of joint rating. This process is based on verifying joint performance against criteria such as general appearance, anchorage condition, debris accumulation, watertightness, surface damage, riding quality, and ease of maintenance. Detailed assessment of these criteria has many aspects and must allow for the results of full-scale testing. Inspections of bridge joints in the Auckland area of New Zealand indicate that engineers are generally aware of the need for special parapet and kerb treatment, and usually rely on manufacturers' specifications. Some older joint systems do not provide for specific kerb details. It is especially important to specify parapet and kerb details in bridge joints. Discontinuity between the trafficked section of a joint and a kerb element is one of the main reasons for leaking joints and subsequent failures. Guidance on the design and selection of bridge joints is urgently needed, as it can substantially improve the durability of bridge joints, thus reduce their maintenance costs.