Hot-rolled steel sheet piling is more extensively used nowadays in permanent as well as temporary retaining walls. Applications are not only above-ground earth-retaining structures but also composite basement wall construction, urban railway and road cuttings, bridge abutments, river bridge pier caissons, as well as the traditional river and coastal protection works. Economic design is enabled by better knowledge of soil–structure interaction and highly developed design and analysis programmes.
Box piles are particularly suitable for marine structures, such as jetties and dolphins, where part of the pile shaft is exposed above seabed level and the pile functions as a free-standing column or is connected at the head in clusters of columns.
Box piles are formed by welding two or more sheet pile sections together. Both Larssen and Frodingham steel sheet piles (see section 29.2.3) can be used.They can be introduced into a line of sheet piling at any point where local heavy loads are to be applied, for instance beneath bridge beams, or used separately.They are clutched together with adjacent sheet piles and can be positioned in a sheet pile abutment so that its appearance is unaffected.
Larssen box piles are formed by welding together two sheet pile sections with continuous welds, and Frodingham plated box piles are formed by continuously welding a plate to a pair of interlocked and intermittently welded sheet piles (see Fig. 29.2).
Special box piles can be formed using other combinations of sheet piles.
(This article comes from thecivilbuilders.com editor released)