fifteen wood construction: connections Wood Connections 1 - PowerPoint PPT Presentation

E LEMENTS OF A RCHITECTURAL S TRUCTURES : F ORM, B EHAVIOR, AND D ESIGN ARCH 614 D R. A NNE N ICHOLS S PRING 2019 lecture fifteen wood construction: connections Wood Connections 1 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Connectors • joining – lapping – interlocking – butting • mechanical – “third - elements” • transfer load at a point, line or surface – generally more than a point due to stresses Wood Connections 2 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Wood Connectors • adhesives – used in a controlled environment – can be used with nails • mechanical – bolts – lag bolts or lag screws – nails – split ring and shear plate connectors – timber rivets Wood Connections 3 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Wood Connections • mechanical Wood Connections 4 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Bolted Joints • connected members in tension cause shear stress • connected members in compression cause bearing stress Wood Connections 5 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Tension Members • members with holes have reduced area   • increased tension stress P T    f or   • A e is effective net area t   A A e e Wood Connections 6 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Effective Net Area • likely path to “rip” across • bolts divide transferred force too Wood Connections 7 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Single Shear • seen when 2 members are connected P P   f  v 2 A d 4 Wood Connections 8 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Double Shear • seen when 3 members are connected      P F 0 P 2 ( ) 2 P P P 2 2    f  v 2 A A 2 d 4 Wood Connections 9 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Bearing Stress • compression & contact • stress limited F= by species & grain direction to load • projected area P P   f p A td projected Wood Connections 10 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Bolted Joints • twisting www.timber.org.au • tear out – shear strength – end distance & spacing Taylor & Line 2002 Wood Connections 11 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Nailed Joints • tension stress (pullout) • shear stress nails presumed to share load by distance from centroid of nail pattern Wood Connections 12 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Nailed Joints • sized by pennyweight units / length • embedment length • dense wood, more capacity *NDS Wood Connections 13 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Connectors Resisting Beam Shear • plates with p – nails p y p 8” – rivets 2” 4.43” 4” x – bolts y a 2” 12” • splices longitudin  V VQ al • V from beam load p I related to V longitudinal VQ   connected area nF p connector I Wood Connections 14 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614

Vertical Connectors • isolate an area with vertical interfaces VQ p   connected area nF p p connector I p Wood Connections 15 Elements of Architectural Structures S2019abn Lecture 15 ARCH 614