Structural Performance of Clay pipes

Although clay pipes are rigid and do not distort under load, the structural performance of modern clay drainage systems ensure a rigid pipeline with flexible joints capable of compensating for settlement after laying.

In open cut installations, clay pipes’ high structural performance, strength and rigidity mean that they can often be laid directly on a trimmed trench bottom, with zero or minimal bedding or with recycled aggregates (e.g. crushed demolition waste): for further information, see the publication “Bedding Construction and flow capacity of Vitrified Clay Pipes”.

In contrast, the backfill forms an integral part of the structural integrity of a flexible pipeline which otherwise has little inherent strength and will flatten under relatively light loads. This typically necessitates carefully surrounding plastic pipes with a bed of limited resource natural aggregate-single-sized pea gravel or similar material.

The implications are that rigid pipelines such as clay drainage have limited vulnerability to poor site practice whereas flexible pipelines have greater dependency on good site practice, with e.g. inadequate bedding or compaction potentially compromising the pipeline’s structural integrity.