Calculation of the weakening coefficient for drum hole bridges
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For cylinders with an actual weakening coefficient ψs ≤ 0.4, the holes that require reinforcement are already self-reinforced and no additional reinforcement is needed. I understand what this sentence means, but in this case, is it still possible to use the coefficient of weakening for arch bridges? Please help, experts!
The cylinder weakening coefficient mentioned here refers to the case of reinforcement with a single hole; the hole-bridge weakening coefficient must certainly be taken into account.
I’m sorry, may I ask again? According to GB/T16508.3-2013, clause 6.6.4, when the pitch between adjacent holes is less than the So value determined by equation (23), and the diameter of both holes does not exceed the maximum allowable diameter for unreinforced holes as specified in 13.3.6, the hole bridge weakening coefficient shall be calculated in accordance with the provisions of 6.6.6 to 6.6.12. I raised this question after seeing this statement, because there should probably also be a rule stating that for cylinders with an actual reduction factor of ψs≤0.4, it is not necessary to calculate the hole-bridge reduction factor when the aperture is smaller than a certain value.
Personal understanding: Any opening in the cylinder reduces its strength, whether it’s a large hole or a small one. For individual openings, those that are small do not require reinforcement, while larger openings do need it. For multiple holes, there should be hole bridges between them to provide weakening, and the extent of this weakening depends on the distance between the holes; of course, such hole bridges do not include reinforcement holes (referring to large holes and small holes, with large holes requiring reinforcement). The situation you described is like having two openings; the weakening of the bridge caused by these openings is minimal when the distance between them is large, and no reinforcement is needed for either opening, so this weakening can be ignored.