Sandberg can carry out laboratory load testing of manhole and gully tops to assess the performance of covers, gratings, frames, and associated support assemblies. Testing can be used for product verification, compliance checks, investigation of defects, or assessment of bespoke fabricated units.
Performance Evaluation Under Applied Loads
Testing is typically undertaken with reference to BS EN 124, which classifies manhole and gully tops by their load-bearing capacity. Sandberg can carry out testing up to E600, equivalent to a 600 kN test load.
The test methodology normally includes two main stages:
Permanent Set Test
Stage 1 is a permanent set test. The test item is subjected to repeated loading cycles up to two-thirds of the required peak test load. After the final unloading cycle, the remaining permanent deformation is measured and checked against the allowable limit for the relevant class and clear opening.
Load-bearing Capacity Test
Stage 2 is a load-bearing capacity test. The cover, grating, frame, or assembly is then loaded up to the required full test load. During the test, deflection, cracking, movement, distortion, or other signs of distress are monitored to assess whether the unit can safely withstand the specified load.
Deflection can be monitored during testing using displacement gauges positioned to suit the loading arrangement and geometry of the test item. This provides recorded load and deflection data, allowing the performance of the manhole or gully top to be assessed under controlled laboratory conditions.
