Influence of Operating Conditions on a Cast-Iron Manhole Cover

Abstract

Manhole covers must provide adequate strength and durability over the intended service life. In addition to operating loads, the lifespan of cast-iron manhole covers is strongly influenced by the conditions of installation and cover placement after opening or closing. These can include a vertical displacement from the plane of the carriageway during installation or the settlement of the terrain around the cover afterwards. After opening and closing the cover, the lid often only partially touches the support surface due to stones or other impurities caught on the surface or under the cover. These events can significantly affect the lifespan of the cover. In this study, an improved geometry of the cast-iron cover is proposed and analysed from an operational strength point of view. Initially, the geometry and potential critical points were scrutinized, and typical loads on the cover were determined. A numerical model was then set to simulate the behaviour during typical operation. In the simulations, the impact of the critical scenarios was analysed by dividing the impact parameters into individual levels. The simulation results reveal the suitability of the improved cover geometry.

Keywords

• manhole cover
• design
• operating conditions
• durability
• cast iron