Development and application of H-joint steel pipe sheet piles in construction of foundations for structures

This paper shows development and application potential of newly developed H-joint steel pipe sheet piles (SPSPs) in SPSP structures. The authors have developed a new H-joint SPSPs technology from a simple idea in which two steel pipes are connected by H-steel section welded on them in order to improve the performance and widen application areas of SPSP technology. The H-joint SPSP is expected to remediate problems of traditional joints in SPSPs. Installation accuracy, proposed field segment joint using a fillet welded splice plate and lateral bearing capacity for H-joint SPSPs were examined by field construction tests, full-scale bending tests and centrifuge model tests, respectively. Parametric studies using beam analysis were conducted to show that the cross sectional dimensions of SPSP foundations can be reduced by using H-joint SPSPs and to estimate a joint efficiency (μ) for design of H-joint SPSP foundation structures. The following observations were made from the studies: (1) H-joint SPSP can be installed with high driving accuracy due to rigidly welding 2 steel pipes and H-steel in a factory, (2) The proposed field segment joint for H-joint SPSP using a splice plate is strong and effective in bending, (3) H-joint SPSPs have high rigidity hence large lateral bearing capacity making them suitable in ensuring the stability of SPSP foundation structures, (4) A joint efficiency of H-joint SPSP foundation is larger than that of SPSP foundation with traditional joints, and (5) H-joint SPSP contributes to reducing the number of piles based on the reduction of the size dimension of the SPSP foundation.