| 摘要 |
PROBLEM TO BE SOLVED: To prevent the strain of a cylindrical body, and further prevent deformation and breakage due to fatigue by continuously connecting the cylindrical body communicating with an underground pipe passage from a road surface to an earth pressure resistant auxiliary cylinder on the upper end edge of a resin-made base cylinder. SOLUTION: A frame body 51 is installed on the circumferential edge of the upper end of the cylindrical body 10 such as a cylinder for a manhole communicating with underground pipe passages 12, 13 from a road surface, and a road surface cover 52 is installed on the upper part thereof. The cylindrical body 10 is continuously connected to an earth pressure resistant auxiliary cylinder 30 on the upper end edge of a resin-made base cylinder 20, and the frame body 51 is installed on the upper end circumferential edge of an earth pressure resistant auxiliary cylinder 30. Thus, earth pressure changed when vehicles and persons come and go around the circumference of the frame body 51 is applied on the earth pressure auxiliary cylinder 30, the resin-made base cylinder 30 is prevented from being strained, in addition, deformed by fatigue and further broken.
|
