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Design Method
The design of joints using Mitek nailplate connectors is governed by the British Board of Agrement Certificate 90/2386 and WIMLAS Certificate 038/96.
Within the approval certificates the conditions of use, assessment of fitness for purpose, sizes of available nailplates, methods of joint assembly, relevant
loadings etc are specified. It is not intended in this document to reproduce in part or in whole the contents of the Certificates; copies of these are available on request from MiTek.
However, to give an insight into the method of joint design using the nailplates, the Designer should note that each nailplate joint  must be assessed for shear strength and lateral resistance to the forces placed upon its integral teeth.
The values for shear and tensile strength are given in the relevant Certificate, as are the values for the nail anchorage loads. It should be noted that the lateral resistance of a nailplate joint depends upon:

1.The number of effective nails in the joint.
2.The species of timber used and its condition (moisture content).
3.The duration of the loading applied.
4.The direction of bearing of the nails in relation to the grain of the timber (load to grain).
5.The direction of the loading in relation to the connector plate (load to nail).
It should be noted that, when designing a nailplate joint, the approval Certificates define certain ineffective areas at the ends and edges of the timber in which the nails are to be ignored for the design.
Further, the species of timber used and the duration of loading causing the forces must be taken into account.

Finally, the actual position of the nailplate on the joint will affect the permitted values for each nail.
It can be seen that this leads to a highly complex interaction, as several different load durations, combined with a number of possible nailplate orientations and a large number of available sizes of nailplate makes the most economical choice of any particular nailplate a difficult decision.

By its nature, the solution of this interaction is now largely handled by MiTek's sophisticated computer programs although manual design is still necessary for very special applications.