Tunnel for vehicle passage, has work window defined by extreme surfaces of inverted lower arch and upper vault in each segment ring of reinforced concrete tubular covering and by intersecting arched and longitudinal reinforcing bars

摘要

A tunnel has a reinforced concrete tubular covering constructed of segment rings. Each segment ring is divided into two units defining an inverted lower arch and an upper vault supported by welded three-dimensional reinforcing structures. Each reinforcing structure consists of arched and longitudinal reinforcing bars intersecting together. The intersecting bars and the extreme surfaces of the upper vault and lower arch of each segment ring define a work window. The reinforcing bars support the work window from inner and outer sides when applied with concrete.