Fields of Application
- SEM/NATM excavation
- Passive support system for the excavated cross section
- Profile template for the excavation geometry
- Bearing for pre-support elements
Basic Concept
Lattice girders have been developed for special demands in the field of Tunneling. The system has been extensively tested and used successfully for numerous tunnel projects throughout the world. Lattice girders ensure an immediate support in the open span area. Contrary to standard solid-web girders, lattice girders are entirely integrated in the shotcrete lining; porous zones and shotcrete spray shadows are avoided. The load-bearing capacity of lattice girders has been investigated in terms of various loading tests and by numerical analysis. Flexibility regarding geometry and bearing capacity characterizes this passive support system for Underground applications.Main Advantages
- Immediate support in the excavation area
- Partial static support action even without shotcrete embedding
- Utilization as a true-to-form template for shotcrete application
- Easy and quick assembly
- Simple handling and installation by a small crew
- Optimum bond and interconnection with the shotcrete lining
- Simple adjustment and shaping to the excavation geometry
- Ideal bearing for spiles and lagging boards
- Spiles may be installed both above or through the lattice girders
- No need for investment in major equipment