Design Pitzl Brackets to Eurocode 5

Pitzl Metallbau GmbH & Co. KG (Essenbach, Germany) manufactures the GePi range of one-piece, non-welded, face-fixed steel angle brackets for timber structures. The brackets are recognised under ETA-21/0750. SPEC Toolbox designs them to Eurocode 5 on the characteristic capacities of that assessment.

The integration follows the GePi range as assessed in ETA-21/0750, grouped by bracket type. The brackets are steel grade S250GD with a Z275 zinc coating, fixed to the timber with 8 mm self-tapping screws and to concrete or steel with metal anchors or concrete screws. Screw supporting plates are aluminium EN AW-6082 T6 or steel S235, as are the optional tension and shear plates.

Angle brackets

• GePi 80, GePi 100 and GePi 240, each integrated with the Sylodyn NC elastic interlayer and without it. Each configuration carries its own capacities and slip moduli.

Flat plate connector

• GePi PLANE, a flat connector plate assessed with the elastic interlayer, in the two shear directions only.

Supporting plates and accessories

• Screw supporting plates sized to each bracket, Sylodyn NC interlayers at 4 mm and 8 mm, and tension plates for adjustment to the timber part.

At a glance, the Pitzl GePi brackets support:

• Timber-to-timber, timber-to-concrete and timber-to-steel connections, including wall-to-slab, wall-to-wall and beam-to-purlin nodes.
• A single bracket, or a bracket on each side of the fastened timber member.
• Solid timber, glulam, CLT, plywood and wood-based structural panels from 290 to 420 kg/m3, and LVL, PSL and LSL to 500 kg/m3 with the screws in the wide face.
• Tension and uplift (F1) and the two orthogonal shear directions (F2/F3 and F4/F5), with a combined-force interaction check.
• Configurations with and without the Sylodyn NC acoustic interlayer.
• Service classes 1 and 2, and service class 3 where corrosion protection to Eurocode 5 is applied or stainless steel of equivalent strength is used.

• The acoustic interlayer sits inside the assessment. Each GePi bracket is assessed both with and without a Sylodyn NC elastomer interlayer, so a vibration-isolated wall-to-slab connection is designed on assessed values rather than on a derated bare-steel bracket.
• Density conversion differs by load direction. Capacities are tabulated at 385 kg/m3 and converted by k_dens, with an exponent of 0.5 in the F1 direction and 0.8 in the shear directions. The conversion is given only for brackets without the interlayer.
• Three orthogonal directions with an interaction rule. F2 and F3 act in opposite directions, as do F4 and F5, so only one of each pair is taken with F1 in the quadratic combined-force check.
• Slip moduli per direction and per configuration. Mean slip moduli are given for each bracket, load direction and build-up, with the ultimate limit state value taken as two thirds of the serviceability value.
• The anchorage step is tabulated. Uplift on the bracket is converted into a design tensile force on the anchors through a tabulated foundation factor, given per bracket and supporting member.

The Pitzl GePi brackets are available in the bracket connection module and CLT Shear Wall calculator, worked to Eurocode 5:

• angle bracket connections carrying uplift, shear and combined loading;
• flat plate connections carrying shear.

Capacities are selected for the assigned strength class and density, the bracket configuration and the load direction, with the combined-force interaction applied where directions act together.

Design follows Eurocode 5 (EN 1995-1-1). ETA-21/0750 gives characteristic load-carrying capacities in the F1 (tension and uplift) direction and in the two orthogonal shear directions F2/F3 and F4/F5, together with mean connection slip moduli. The design capacity is the lesser of the timber-connection failure (screw withdrawal and embedment, with k_mod and the connection partial factor), the steel-plate failure with the steel partial factor, and, where the bracket is anchored to concrete, the anchor failure with its own partial factor. The tabulated values are tested capacities for the complete connection; the net cross-section at the screw holes, the minimum end and edge distances, the effect of a panel interlayer on the screw lateral capacity, and the anchor design are verified separately to Eurocode 5 and EN 1992-4.