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TW Catalogue EN Int. 03-2015

30 03/2015 11 WT / WR Connection of purlins to main trusses 2/5 Proposal of designProposed dimensions Tensile force 1 Types of arrangement Dimensions For calculating the rafter-supporting purlins, the loads must first be converted into components FII and F respectively FZD parallel and perpendicular to the roof surface. Calculation of the purlins consists of two parts. 1) Stress parallel to roof surface (FII) In the first part, shearing is demonstrated as a function of the arrangement of the WT fastener. 2) Stress perpendicular to roof surface ( FD / FZ ) In the second part, the most unfavourable loading of the WT fastener inserted straight must be calculated irrespective of fastener arrangement 1 to 3. brs-a brs-a cleat hrs hrs hrs a 45° a a45 brs-a a FD Z 1 FII FZ FZ Z 2 FII Z 3 FII brs-a hrs hrs hrs a brs-a a brs-a a Z1 = · FII · hrs – FD · + 3 2 · (brs – a) brs 6 a 3 Tensile force 2 Z2 = · FII · hrs – FZ · – a + FZ 3 2 · (brs – a) brs 2 Tensile force 3 Z3 = · – FII · hrs + FZ · – a + FZ 3 2 · a brs 2 Fastener arrangement 1 Suitable for shallow pitched roofs (P ≈ 0° to 5°), depending on load- ing. In the absence of upward loads, the WT fastener can also be inserted eccentrically to improve load-bearing capacity against tilting. V = FII Calculation of the cleat attachment for shearing force V according to WT Data sheet No. 01 V = FII Z45 = FII · 2 Fastener arrangement 3 Suitable for steeply pitched roofs (P ≈ 10°), depending on loading. In the absence of upward loads, the WT fastener can also be inserted eccentrically to improve load-bear- ing capacity against tilting. Fastener arrangement 2 Suitable for moderately pitched roofs (P ≈ 5° to 15°), depending on loading. In the absence of upward loads, the WT fastener inserted straight can also be inserted eccen- trically to improve load-bearing capacity against tilting. P cleat P The highest of these 3 tensile forces is relevant for the loading of the WT fastener: Max. tensile force: Z = max (Z1, Z2, Z3) P Suitable for shallow pitched roofs (P 0°to 5°), depending on loading. In the absence of upwardloads, the WT/WR fastener can also be inserted eccentrically to improve load-bearing capacity against tilting. Suitable for moderately pitchedroofs (P 5°to 15°), depending onloading. In the absence of upwardloads, the WT/WR fastener insertedstraight can also be inserted eccen-trically to improve load-bearing capacity against tilting. Suitable for steeply pitched roofs (P 10°), depending on loading. Inthe absence of upward loads, the WT/WR fastener can also be inserted eccentri- cally to improve load-bearing capacity against tilting. In the first part, shearing is demonstrated as a function of the arrangement of the WT/WR fastener. Calculation of the cleat attachment for shearing force V according to WT/WR Data sheet No. 01 In the second part, the most unfavourable loading of the WT/WR fastener inserted straight must be calculated irrespective of fastener arrangement 1 to 3. The highest of these 3 tensile forces is relevant for the loading of the WT/WR fastener: Max. tensile force: Z= max (Z1, Z2, Z3) Technical documentation and data sheets 11. 3003/2015

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