Calculation for strengthening the opening of manholes
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There is now a Class III container that requires an access hatch to be installed on it; how should the reinforcement for this opening be calculated? Should reinforcement be added for the flat cover openings? I hope the experts here can give me some advice
I currently have a DN500 manhole cover on which I need to install fittings of DN15 and DN150. For the DN15 fitting, since it corresponds to a size of 150, there is no need to calculate any reinforcement for the opening; however, this calculation is necessary for the DN150 fitting. I’m not sure how to carry out this calculation – should it be done using the methods applicable to reinforcing openings in flat covers?
Treat the DN500 manhole as a container (without considering the lower cover) and then perform reinforcement calculations based on the openings in the flat cover. Also, I think in the calculations for flat-panel openings, there is a maximum value for openings of any cross-section; you should still use the opening size of DN150 + DN15 for input.
The flat cover opening reinforcement involves calculating the total maximum diameter of openings in the same diameter direction; the conditions for exemption from reinforcement mentioned by the original poster do not apply here.