Rigorous testing is the foundation of the GMI composite manhole cover and frame system. The GMI load testing regimen demands ultimate performance in cyclical fatigue, proof-load, & destructive testing.
GMI composite manhole covers have a proven field history and have stood up to the most severe environments in the world. Environmental exposure tests are conducted in a laboratory setting, and are further reinforced with successful field testing and extended service life.
GMI composite manhole cover and frames have an average proof load in excess of 100,000 lbs - more than five times the H-20 loading standard as called out in AASHTO (American Association of State Highway and Transportation Officials) Standard Specifications for Highway Bridges.
GMI maintains world class testing equipment on premises - production is randomly sampled and tested during the manufacturing process. Independent certification and test witnessing is available for the following internationally accepted test standards:
United States Standard - AASHTO M 306 Standard Specification for Drainage, Sewer, Utility, and Related Castings, described as:
H-20 & HS-20: A 40,000 pound proof load concentrated on a nine inch by nine inch square area and held for one minute. The 40,000 lbs. proof load represents a safety factor of 2.5 for H-20 & HS-20 loading.
H-25 & HS-25: A 50,000 pound proof load concentrated on a nine inch by 22nine inch square area and held for one minute. The 50,000 lbs. proof load represents a safety factor of 2.5 for H-25 & HS-25 loading.
European Standard: EN-124 for Gully Tops and Manhole Tops for Vehicular and Pedestrian Areas. Proof load & permanent set testing for classes:
A - 15 kN: Areas which can only be used by pedestrians and pedal cyclists.
B - 125 kN: Footways, pedestrian areas and comparable areas, car parks or car parking decks.
C - 250 kN: For gully tops installed in the area of kerbside channels of roads.
D - 400 kN: Carraigeways of roads (including pedestrian streets), hard shoulders and parking areas, for all types of road vehicles.
E - 600 kN: Areas imposing high wheel loads, e.g. docks and aircraft pavements.
GMI composite manhole cover systems withstand the harshest corrosive environments, including exposure to:
GMI products have been tested to destruction at temperature extremes of -60 degrees Fahrenheit and 160 degrees Fahrenheit. There was no loss in performance when tested at both extreme heat and extreme cold.
Ultraviolet radiation will not affect the long term performance of GMI composite manhole cover systems.
Test results and referrals can be furnished upon request.