A manhole position identification method of the present invention includes: measuring, from an end of an optical fiber, a temporal variation in scattering light from the optical fiber when an impact blow is applied to a cover of a manhole located on a path of the optical fiber, so as to obtain temporal variations in a scattering light intensity distribution in a longitudinal direction of the optical fiber; determining an occurrence of vibration due to the impact blow based on the temporal variations at positions in the scattering light intensity distribution, so as to identify an impact blow position on the optical fiber; and associating the impact blow position on the optical fiber with a map position of the manhole whose cover has received the impact blow, so as to identify a position of the manhole expressed in terms of optical fiber length from the end.

A manhole position identification method of the present invention includes: measuring, from an end of an optical fiber, a temporal variation in scattering light from the optical fiber when an impact blow is applied to a cover of a manhole located on a path of the optical fiber, so as to obtain temporal variations in a scattering light intensity distribution in a longitudinal direction of the optical fiber; determining an occurrence of vibration due to the impact blow based on the temporal variations at positions in the scattering light intensity distribution, so as to identify an impact blow position on the optical fiber; and associating the impact blow position on the optical fiber with a map position of the manhole whose cover has received the impact blow, so as to identify a position of the manhole expressed in terms of optical fiber length from the end.

A manhole frame includes one or more handholds near the entrance to the manhole so that the ladder rungs can be made lower and the access space at the entrance to the manhole thereby increased. The handhold can be cast into the cover-supporting lip, or can be a movable handle which is below the level of the manhole when not in use or extended above ground level when in use.

A manhole frame includes one or more handholds near the entrance to the manhole so that the ladder rungs can be made lower and the access space at the entrance to the manhole thereby increased. The handhold can be cast into the cover-supporting lip, or can be a movable handle which is below the level of the manhole when not in use or extended above ground level when in use.

The present invention relates to a wireless communication device inside a manhole, comprising: a communication terminal installed inside a manhole; and an antenna extension cable connected to the communication terminal, wherein the antenna extension cable is electrically connected to a manhole cover of a conductive material which acts as an antenna so as to deliver a signal received from the manhole cover of a conductive material to the communication terminal. The wireless communication device inside a manhole is capable of delivering information regarding the inside of the manhole (equipment inspection, leakage check, etc.) to the outside without the manhole cover being opened. As such, it is possible to resolve traffic congestion caused by manhole check; control facilities inside the manhole without opening the manhole cover; by delivering opening and closing information of the manhole cover, prevent theft of the manhole and obviate safety accidents caused by the opening of the manhole cover; and prevent manhole worker safety accidents by monitoring the working environment during manhole work.

The present invention relates to a wireless communication device inside a manhole, comprising: a communication terminal installed inside a manhole; and an antenna extension cable connected to the communication terminal, wherein the antenna extension cable is electrically connected to a manhole cover of a conductive material which acts as an antenna so as to deliver a signal received from the manhole cover of a conductive material to the communication terminal. The wireless communication device inside a manhole is capable of delivering information regarding the inside of the manhole (equipment inspection, leakage check, etc.) to the outside without the manhole cover being opened. As such, it is possible to resolve traffic congestion caused by manhole check; control facilities inside the manhole without opening the manhole cover; by delivering opening and closing information of the manhole cover, prevent theft of the manhole and obviate safety accidents caused by the opening of the manhole cover; and prevent manhole worker safety accidents by monitoring the working environment during manhole work.

A manhole cover assembly for a sewer, the manhole cover assembly including a manhole cover having a top surface and a bottom surface. An opening extends through the manhole cover between the top surface and the bottom surface. The assembly further includes an extension pipe coaxially aligned with the opening of the manhole cover and extending from the top surface of the manhole cover, wherein the extension pipe is coupled to the manhole cover with a locking mechanism.

A manhole cover assembly for a sewer, the manhole cover assembly including a manhole cover having a top surface and a bottom surface. An opening extends through the manhole cover between the top surface and the bottom surface. The assembly further includes an extension pipe coaxially aligned with the opening of the manhole cover and extending from the top surface of the manhole cover, wherein the extension pipe is coupled to the manhole cover with a locking mechanism.

Manhole inserts suitable for deployment in a manhole opening of a manhole structure may include a manhole insert bottom. A manhole insert sidewall may extend from the manhole insert bottom. A manhole insert flange may extend from the manhole insert sidewall. A manhole insert gasket may be on the manhole insert flange, The manhole insert gasket may include a solidified, hardened, and cured gasket material having a synthetic silicone elastomer. The manhole insert gasket may be configured to remain exposed on the manhole insert flange prior to deployment of the manhole insert in the manhole opening of the manhole structure.

Manhole inserts suitable for deployment in a manhole opening of a manhole structure may include a manhole insert bottom. A manhole insert sidewall may extend from the manhole insert bottom. A manhole insert flange may extend from the manhole insert sidewall. A manhole insert gasket may be on the manhole insert flange, The manhole insert gasket may include a solidified, hardened, and cured gasket material having a synthetic silicone elastomer. The manhole insert gasket may be configured to remain exposed on the manhole insert flange prior to deployment of the manhole insert in the manhole opening of the manhole structure.