CIRCULAR & ELLIPTICAL SHAFTS: FUNDAMENTAL DESIGN AND TUNNELING APPLICATION USING STEEL RIBS & LINER PLATE-PPT Presentation

PPT Presentation

Pdf Summary

The presentation outlines the use of steel ribs and liner plate for circular and elliptical shaft support. Its goals are to explain the design methodology and demonstrate ribs and liner plate as a viable shaft-support option.<br /><br />Four-flange liner plates are segmental steel components used in shafts, tunnels, mining, sewer lining, and as lagging between standing supports. Made from A1011 steel, they are available in several thicknesses, widths, shapes, and finishes, including corrugated or smooth plates and site-specific coatings. Tapered plates can accommodate horizontal and vertical curvature.<br /><br />The presentation highlights the advantages of circular geometry. Cold-formed ribs create arching action, converting ground pressure into compressive thrust and generally reducing bending. This can allow smaller, lighter beams and reduce labor, installation time, and cost.<br /><br />Rib design uses an allowable-stress approach informed by established engineering methods. It evaluates arching-related thrust and flexure, as well as buckling caused by compressive forces; rib stiffness and the spacing of blocking points are important considerations. Liner plate serves as lagging within the support system.<br /><br />The presenter notes that the opinions and recommendations are his own and are not endorsed or guaranteed by the Deep Foundations Institute.

Keywords

steel ribs

liner plate

circular shaft support

elliptical shaft support

segmental steel components

arching action

allowable-stress design

buckling analysis

shaft lining

cold-formed ribs