Larssen sheet piling
Larssen sheet piling is a kind of sheet piling retaining wall. Segments with indented profiles (troughs) interlock to form a wall with alternating indents and outdents. The troughs increase resistance to bending. The segments are typically made of steel or another metal.{{cite journal |title=Annotated bibliography on steel sheet pile structures |journal=Fritz Laboratory Reports |date=March 1967 |last=Krugmann |first=P. K. |last2=Boschuk |first2=J. Jr. Boschuk |last3=Fang |first3=H. Y. |url=https://preserve.lehigh.edu/cgi/viewcontent.cgi?article=1364&context=engr-civil-environmental-fritz-lab-reports |format=PDF |accessdate=2019-12-19 }}
Larssen sheet piling was developed in 1906 by Tryggve Larssen, engineer from Bremen (Germany).{{cite book | last=Hettler | first=A. | last2=Kurrer | first2=K.E. | title=Earth Pressure | publisher=Wiley | year=2019 | isbn=978-3-433-60898-2 | url=https://books.google.com/books?id=pPm4DwAAQBAJ&pg=PA85 | access-date=2019-12-20 | page=85}}{{cite book | author=American Society of Civil Engineers | title=Transactions of the American Society of Civil Engineers | publisher=The Society | series=Transactions of the American Society of Civil Engineers | issue=v. 64 | year=1909 | url=https://books.google.com/books?id=68zVAAAAMAAJ&pg=PA487 | access-date=2019-12-20 | page=487}}{{cite book | title=Comptes rendus du quatorzième conférence internationale de Mécanique des sols et des travaux de fondation, Hambourg, 6-12 septembre 1997 | publisher=A.A. Balkema | series=Proceedings of the fourteenth International Conference on Soil Mechanics and Foundation Engineering, Hamburg, 6-12 september 1997: volume 4 : post conference proceedings | year=1997 | isbn=978-90-5410-895-5 | url=https://books.google.com/books?id=qyn-fbMnKm4C&pg=PA2084 | language=fr | access-date=2019-12-20 | page=2084}} Its applications include piers, oil terminals, waste storage facilities, shoreline protection,{{cite journal |title=Steel sheet piling in coast-protection works |journal=Shoreline Protection |year=2015 |last=Morley |first= J. |last2=Waite |first2= D. |last3= O'brien |first3=J. E. |volume=24 |doi=10.1680/sp.01732 |isbn=978-0-7277-4933-8 }} bridges, houses, buildings, dry docks, other construction sites, and for the strengthening of pond banks, preventing slumping into a pit, and flooding.{{cite patent|country=US| number=839608A|status=patent|title=Sheet Piling|pubdate=1906-12-25|gdate= 1906-12-25|fdate=1906-03-01|url=https://patentimages.storage.googleapis.com/f1/85/c9/ce796c85a5631a/US839608.pdf|inventor=Tryggve Larssen}}{{cite book | last=Smoltczyk | first=U. | title=Geotechnical Engineering Handbook, Elements and Structures | publisher=John Wiley & Sons | series=Geotechnical Engineering Handbook | year=2003 | isbn=978-3-433-01451-6 | url=https://books.google.com/books?id=O3UQCQWAr7cC&pg=PA451 | access-date=2019-12-19 | page=451}}{{cite conference |last=Zhao |first=Tianchi |last2=Ding |first2=Wenqi |last3=Wei |first3=Lixin |last4=Wu |first4=Weifeng |title=The Behavior Analysis of a Cofferdam Constructed by Double Sheet Pile Wall Above Muck |conference=GeoShanghai International Conference |year=2017 |doi=10.1007/978-981-13-0017-2_3 }}
Construction
Lengths can reach 36 meters.
Each segment is flipped 180° versus the preceding segment. The segments lock together using a variety of interconnections.{{cite book |last=ThyssenKrupp GfT Bautechnik |url=https://www.academia.edu/36962855|format=PDF |title=Sheet Piling Handbook |edition=3 |year=2010 |accessdate=2019-12-19 }}
The fully assembled structure is formed in a linear, circular, or other shape.
To reduce the filtering space, mixed sealant is injected. Additionally, it may be combined with the use of dowels, metal beams and pipes.{{cite book | last=Tsinker | first=G. | title=Handbook of Port and Harbor Engineering: Geotechnical and Structural Aspects | publisher=Springer US | year=2014 | isbn=978-1-4757-0863-9 | url=https://books.google.com/books?id=OCblBwAAQBAJ&pg=PR31 | access-date=2019-12-19 | page=31}}
Metal dowels are hot-rolled steel and cold-rolled.
Design
- Tongue Larssen - Tongue Larssens are up to 34 meters long and 80 centimeters wide. They have locks, which allow people to connect one profile to another vertically to create a sealed metal diaphragm wall. Transverse profiles can be in the shape of letters: S, Z, L or Ω (Omega) where the trough can be of varying depth.{{citation needed|date=December 2019}}
- Special Profile - Special profiles are long and narrow without locks. They usually have a wavy or trough shape to increase the resistance to bending.{{citation needed|date=December 2019}}
- Cantilever - Bending moments and shears are calculated under the assumption that the wall is a cantilever beam fixed at the bottom of the wall.{{citation needed|date=December 2019}}
- Anchored Wall Design- Bending moments, shears, and anchor force are calculated under the assumption that the wall is a beam with simple supports at the anchor elevation and at the bottom of the wall (the place where the wall moves beneath the surface of the ground. With the bottom of the wall at the penetration consistent with a factor of safety of 1, the lateral reaction at the bottom support will be zero and the lateral reaction at the upper support will be the horizontal component of the anchor force.{{citation needed|date=December 2019}}
Applications
Larssens are used in foundation pits, coastline strengthening, bridge construction, piers, tide control, flood protection, agriculture irrigation, water reservoir and other work requiring extremely strong support in a narrow geometry.