**This page includes notes related to the relevant Eurocodes EC5 ( BS EN 1995-1-1 ). On the Roymech website I have also
provided information on timber which relates to BS 5268 Timber Index this is now
superseded by the eurocode. My information on the older standards is generally more detailed and much of the information is still relevant. **

Introduction....
Formwork....
Standards....
Symbols....
Loading on lateral joints ....
Characteristic Embedment strengths....
Edge and distance spacing.....
Screws....
Nails....
Bolts...
Dowels....

Introduction This page includes notes on design of timber connections including nails, screws, dowels and bolts.
The notes are outline in nature suitable for enabling basic calculations. For detailed design
it is necessary to refer to the actual standard and all of the associated standards. Relevant Standards .
symbols
Load Carrying capacity of nails , bolt, screws and dowels t Single Shear :Characteristic load carrying capacity of nails , dowels screws and bolts and staples per shear plane in line with BS EN 1995-1-1 (8,2,2). Use minimum value from above equations. t DoubleShear :Characteristic load carrying capacity of nails , dowels screws and bolts and staples per shear plane in line with BS EN 1995-1-1 (8,2,2). Use minimum value from above equations.
Characteristic Embedment strengths
Nails (not pre-drilled)..f
where Minimum Edge and Spacing distances
Minimum edge and spacing distances for Bolts...Applicable to screws with d over 6 mm
Minimum edge and spacing distances for Dowels...
Minimum edge and spacing distances for Nails......Applicable to screws with d less than 6mm
Screws Laterally loaded screws. When the smooth diameter of the screw
penetrates the point side of a joint by more than 4.d then d When the screw diameter is greater than 6mm the strength /spacing rules applicable to
bolts applies. The embedment strength, connection strength and spacing / distance requirements for screws are shown in the sections above. Characteristic Embedment strengths..... Edge and distance spacing..... Axially loaded screws. withdrawel failure of the threaded portion of the screw minimum edge and end distances and spacings of axially loaded screws are provided in the table below
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where NailsLaterally loaded nails. A nail is either smooth or grooved. The embedment strength, connection strength and spacing / distance requirements for nails are shown in the sections above. Characteristic Embedment strengths..... Edge and distance spacing..... Timber at risk of splitting should be predrilled for nails when As an alternative to this rule the edge distances above may be adjusted such that
for ρ For one row of nails in a row parallel to the grain ,the load carrying capacity parallel to the grain is where For nails the effective number of fasteners = where
Axially Loaded Nails Only nails which are classified as threaded should be used for withstanding axial loads. A threaded nail has its shank profiled or deformed over a minimum of 4,5d and has a characteristic withdrawel parameter
f Only the threaded part of the nail is considered capable of transmittting axial loads. The characteristic withdrawel capacity of nails F where Timbers at risk of splitting include douglas fir and Spruce. BoltsLaterally loaded bolts For one row of n bolts parallel to the grain direction, the load-crrying capacity parallel to the grain, should be calculated using the effective number of bolts n where For loads perpendicular to grain the effective number of bolts = n The embedment strength, connection strength and spacing / distance requirements for bolts are shown in the sections above. Characteristic Embedment strengths..... Edge and distance spacing..... Axially loaded bolts The axial load capacity of a bolt should be taken as the lower value of The bearing capacity of a washer should be calculated assuming a characteristic compressive
strength on the contact area of 3,O f
f The bearing capacity per bolt of a steel plate should not exceed that of a circular washer with a diameter which is the minimum of : 12t or 4d ..(t is thickess of plate and d = diameter of bolt. Dowels The various statements applying to bolts as provided above apply except for the spacing and end
distances. |

- Introduction to Structural Timber design to The Eurocodes..Very important document to latest codes :75 page document
- EN1995-1-1: Section 8 - Connections.. Extremely useful and informative document.