SPEC Toolbox carries Simpson Strong-Tie brackets as live design data for Eurocode 5. Angle brackets and shear angles, hold-downs, shear plates and tension straps are integrated, with characteristic capacities from ETA-06/0106. Capacities are given in five load directions with a combined force interaction, stated at 350 kg/m³ and reduced below it. Design values follow EN 1995-1-1 clause 2.4.3, with lateral fastener capacity taken for a thick steel plate under clause 8.2.3.

Simpson Strong-Tie manufactures structural connection systems for timber, concrete and masonry construction. Its steel bracket range for timber is integrated in SPEC Toolbox.

Hold-downs

• HTT4, HTT5, HTT2E and HTT31 in 2.8 mm and 3 mm plate, and HDUE9, HDUE13 and HDUE17 in 2.5 mm and 3.5 mm plate, together spanning 314 mm to 790 mm in length.

Angle brackets and shear angles

• ABR70, ABR7015, ABR7020, ABR90, ABR9015, ABR9020, ABR100, ABR105, ABR10525, ABR170, ABR220, ABR255, ABRL98, AE48, AE76, AE116 and E5/2, in 1.5 mm to 3 mm plate with legs from 40 mm to 120 mm.

Shear plates

• NPB255, NPB255SO, NPB20100200 and NPB200300 in 2 mm and 3 mm plate, 100 mm to 294 mm square, and LDSS48 in 1.5 mm plate.

Tension straps

• MSTC78 and MDCST48 in 2 mm plate.

The HTT and HDUE hold-downs, LDSS48 and both tension straps are supplied by Simpson Strong-Tie in addition to ETA-06/0106.

The assessed brackets are pre-galvanized S250GD + Z275 steel to EN 10346, with S350GD, heavier Z800 and ZM310 coatings and stainless grades to EN 10088-2 as alternatives. They are fixed with CNA connector nails or CSA connector screws to ETA-04/0013, threaded nails to EN 14592, wood or SS-H timber screws, M8 to M12 bolts, or PDPA-75 pins into steel.

The brackets connect two timber members, a beam to a post, or a timber member to concrete, steel or masonry, in beam to beam, beam to column, post to beam and trimmer arrangements, singly or one each side of the member.

Assessed substrates are solid timber and glued members in classes C14 to C40, glued laminated timber GL24c or better, solid wood panels, LVL, laminated strand lumber, plywood, OSB and CLT, at characteristic densities from 290 kg/m³ to 420 kg/m³.

Capacities are carried in five directions, F1 to F5, covering uplift, shear in the purlin direction and lateral force in the beam direction, with a combined force interaction where they act together. Service classes 1 and 2 apply, and service class 3 with corrosion protection or a stainless grade. Reaction to fire is Euroclass A1.

• The five directions carry two interaction rules: quadratic for F1 with F2 or F3, linear for F1 with F4 or F5, and a third expression where shear and lateral force act with uplift together.
• Many tabulated capacities are expressions in the load eccentricities rather than single values, so the distance of the force from the flap and its height above the beam change what the bracket carries.
• Wane is tolerated under the flap towards the purlin on most brackets, provided it does not fall under the fasteners, with separate reduced values tabulated for that case.
• Slip moduli are published for some brackets, among them ABR9020, ABR100 and AE116, so connection slip can be carried into a serviceability check rather than assumed.

Simpson Strong-Tie brackets are selectable in the bracket connection module and CLT Shear Wall calculator, worked to Eurocode 5, by connection function: hold-downs for tension and uplift anchorage; angle brackets and shear angles for shear and combined loading; shear plates; and tension straps. Capacities follow the timber strength class and density, the fastener set and the load direction, with the interaction and the end, edge and spacing rules applied.

Design follows Eurocode 5 (EN 1995-1-1). ETA-06/0106 gives characteristic capacities in F1 for tension and uplift, F2 and F3 for shear and F4 and F5 for lateral force, plus slip moduli for some brackets. Most values already contain kmod for a stated load duration class, so the design value is that value divided by the partial factor; the rest are plain characteristic values to which kmod is applied.

The design capacity is the lesser of the timber connection failure, with kmod and the connection partial factor, and the steel plate failure, with the steel partial factor. The published values assume a ratio of 1.18 between those factors and are scaled down where a lower ratio applies. Capacities are stated at 350 kg/m³ and reduced below it by kdens. Lateral fastener capacities are taken for a thick steel plate. Splitting perpendicular to the grain, and the fixings into concrete or steel, are verified separately to Eurocode 5.