Many GRP pipes are used in underground pipelines. Of course, some span problems of the underground pipelines need to be calculated relatively.

The connection methods for GRP construction generally include flange connection, sleeve bonding connection, socket bonding connection, flat end bonding connection and thread connection. Before the installation of GRP pipes, all connecting materials such as GRP pipes and their accessories shall be inspected to confirm that the materials meet the design requirements and the quality is qualified before installation. The surface of the glass fiber reinforced plastic pipe shall be smooth and flat, and it is not allowed to , but it is allowed to have different colors, bubbles and wrinkles due to the dewaxing of the glass cloth.

The underground pipeline is supported by pipe supports, hangers and brackets. The distance between the two supporting points is the so-called pipeline span. Of course, the span cannot be too large, which will affect the normal operation of the pipeline. In order to ensure the safety and normal operation of the pipeline, of course, the span of the pipeline should be expanded as much as possible. Under the action of external load, the large stress generated at the pipe interface shall not exceed the allowable stress of GRP.