Selection of the elliptical hole dimensions d and do for strength calculations of pressure boilers and for enhanced verification of manholes.
Thread Content
In the symbol definition, d represents the inner diameter of the insert-type hole ring and the dimension of the elliptical hole in the longitudinal cross-section of the cylinder; do denotes the outer diameter of the welded pipe joint or pipe, with the long axis dimension of the elliptical hole being used. For the manhole device A300×400-1.25, the inner dimensions of its manhole reinforcement ring are 300×400, while the outer dimensions are 340×440. According to the table, d is set to 300; so what about do? 440?
For the strength calculation of oval tubes, it is based on the dimensions of the long axis; as for the reinforcement calculation of manholes, it has nothing to do with 300 – simply use an inner diameter of 400 and an outer diameter of 440 for the calculations.
In the calculations for strengthening manholes, the diameter of the hole is 444, with a gap of 2 mm
The cost for wall reinforcement is calculated at 300, as clearly specified