S2014abn Wood Connections 1

Lecture 15

Elements of Architectural Structures

ARCH 614

fifteen

wood construction:

connections

lecture

ELEMENTS OF ARCHITECTURAL STRUCTURES:

FORM, BEHAVIOR, AND DESIGN

ARCH 614

DR. ANNE NICHOLS

SPRING 2014

S2014abn Wood Connections 2

Lecture 15

Elements of Architectural Structures

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

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Lecture 15

Elements of Architectural Structures

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

S2014abn

• mechanical

Wood Connections 4

Lecture 15

Elements of Architectural Structures

ARCH 614

Wood Connections

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Lecture 15

Elements of Architectural Structures

ARCH 614

• connected members in tension cause

shear stress

• connected members in

compression cause

bearing stress

Bolted Joints

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Lecture 15

Elements of Architectural Structures

ARCH 614

Tension Members

• members with holes have reduced area

• increased tension stress

• Ae is effective net area

ee

tA

Tor

A

Pf

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Lecture 15

Elements of Architectural Structures

ARCH 614

Effective Net Area

• likely path to “rip” across

• bolts divide transferred force too

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Lecture 15

Elements of Architectural Structures

ARCH 614

• seen when 2 members are connected

Single Shear

4

2dv

P

A

Pf

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Lecture 15

Elements of Architectural Structures

ARCH 614

• seen when 3 members are connected

Double Shear

4

2

22

2 dv

P

A

P

A

Pf

)2

(20 PPF

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Lecture 15

Elements of Architectural Structures

ARCH 614

• compression & contact

• stress limited

by species &

grain direction

to load

• projected area

Bearing Stress

td

P

A

Pf

projected

p

F=

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Lecture 15

Elements of Architectural Structures

ARCH 614

Bolted Joints

• twisting

• tear out

– shear strength

– end distance & spacing Taylor & Line 2002

www.timber.org.au

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Lecture 15

Elements of Architectural Structures

ARCH 614

Nailed Joints

• tension stress (pullout)

• shear stress nails presumed to share

load by distance from centroid of nail

pattern

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Lecture 15

Elements of Architectural Structures

ARCH 614

Nailed Joints

• sized by pennyweight units / length

• embedment length

• dense wood, more capacity

*NDS

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Lecture 15

Elements of Architectural Structures

ARCH 614

• plates with

– nails

– rivets

– bolts

• splices

• V from beam load

related to Vlongitudinal

Connectors Resisting Beam Shear

x

y

ya

4”

2”

2”

12”

8” p

p p

4.43”

I

VQ

p

V allongitudin

pI

VQnF

areaconnected

connector

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Lecture 15

Elements of Architectural Structures

ARCH 614

Vertical Connectors

• isolate an area with vertical interfaces

pI

VQnF

areaconnected

connector

p p

p