seventeen rivets steel construction: trusses, decks & plate - PowerPoint PPT Presentation

E LEMENTS OF A RCHITECTURAL S TRUCTURES : Iron & Steel Trusses F ORM, B EHAVIOR, AND D ESIGN ARCH 614 • cast iron D R. A NNE N ICHOLS – 18 th century S PRING 2019 – chain links lecture • wrought-iron seventeen • rivets steel construction: trusses, decks & plate girders http:// nisee.berkeley.edu/godden Steel Trusses 1 Elements of Architectural Structures S2009abn Steel Trusses 2 Elements of Architectural Structures S2009abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 Truss Connections Trusses • gusset plates • require lateral bracing • consider buckling • bolts • indeterminate trusses • welds – extra members – solvable with statics • cables can’t hold compression – displacement methods • elastic elongation http://courses.civil.ualberta.ca – too few members, unstable One Maritime Plaza, SOM 1964 (AISC - Steel Structures of the Everyday) Steel Trusses 3 Elements of Architectural Structures S2009abn Steel Trusses 4 Elements of Architectural Structures S2007abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 1

Manufactured Trusses Open Web Joists • open web joists • SJI: www.steeljoist.com • Vulcraft: www.vulcraft.com • parallel chord – K Series (Standard) • 8-30 ” deep, spans 8-50 ft – LH Series (Long span) • 18-48 ” deep, spans 25-96 ft – DLH (Deep Long Spans) • 52-72 ” deep, spans 89-144 ft – SLH (Long spans with high strength steel) • pitched top chord • 80-120 ” deep, spans 111-240 ft Steel Trusses 5 Elements of Architectural Structures S2007abn Steel Trusses 6 Elements of Architectural Structures S2007abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 Decks Plate Girders • welds • sheet steel • web stiffeners • composite http:// nisee.berkeley.edu/godden Steel Trusses 8 Elements of Architectural Structures S2007abn Steel Trusses 7 Elements of Architectural Structures S2007abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 2

Web Bearing Space Trusses • max loads • 3D with 2 force bodies and pins   – pyramid P ( N 2.5 ) k F t  n(max end) yw w – tetrahedron   ( 5 ) P N k F t  • “ frames ” n(max interior) yw w have fixed joints • layers • 40 ’ s Steel Trusses 9 Elements of Architectural Structures S2007abn Steel Trusses 10 Elements of Architectural Structures S2007abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 Space Trusses Space Trusses • supports • connections http:// nisee.berkeley.edu/godden Steel Trusses 12 Elements of Architectural Structures S2007abn Steel Trusses 11 Elements of Architectural Structures S2007abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 3

Space Trusses Tensegrities • 3D frame • discontinuous struts • continuous cables Free Ride Home – Kenneth Snelson http:// nisee.berkeley.edu/godden Steel Trusses 13 Elements of Architectural Structures S2007abn Steel Trusses 14 Elements of Architectural Structures S2007abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 Method of Sections Method of Sections • relies on internal forces being in • joints on or off the section are good to equilibrium on a section sum moments • cut to expose 3 or less members • quick for few members • coplanar forces   M = 0 too • not always obvious where to cut or sum P P P P . C C AC AC D D F F A . A . E B E B B A AB AB A B y B y Steel Trusses 15 Elements of Architectural Structures S2007abn Steel Trusses 16 Elements of Architectural Structures S2007abn Lecture 17 ARCH 614 Lecture 17 ARCH 614 4