| 摘要 |
The present invention relates to a lattice girder with enhanced strength and improved bonding force between the lattice girder and shotcrete. The lattice girder comprises: an upper steel bar extending along a tunnel; a lower steel bar extending along the upper steel bar with a predetermined space therebetween; and a fixing member for connecting and fixing the upper steel bar and the lower steel bar, wherein the upper and lower steel bars have a polygonal cross-section, and the fixing member includes: an upper contact portion making surface contact with one side of the upper steel bar that has the polygonal cross-section; connecting portions bent on both ends of the upper steel bar, extending towards the lower steel bar; and a lower contact portion bent on the end of the connecting portion and making surface contact with one side of the lower steel bar that has the polygonal cross-section. In this manner, the bonding force between the upper steel bar and the lower steel bar can be improved and the strength of the lattice girder may be enhanced. |
