00 Contents - Hilti Svenska AB

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Concrete base material 6.2 Factors influencing resistance to pull-out Factors that can affect the pull-out strength of fastenings to concrete include: • Depth of penetration into the concrete • Concrete parameter (compressive strength, grain structure, direction of concrete placement) • Distance to concrete edge and fastener spacing Depth of penetration hET Fasteners that are driven deeper typically have a higher resistance to pullout. This relation is best shown by placing groups of fasteners with different driving energy and comparing the results for each group with the others. The result of such a test is shown in the graph at the right. Note that fastener driving failures were not considered in calculation of the average ultimate load, Nu,m. The value of increasing the depth of penetration in order to increase pull-out strength is limited by the increasing fastener driving failure rate. Provided that the penetration depth is the same, fastenings in concrete with a higher compressive strength hold better than fastenings in lower strength con- Pull-out strength and fastener driving failure rate both increase with increasing penetration depth. The optimum depth of penetration is taken as the depth at which the yield in terms of pull-out strength begins to decrease. It’s within a range of 18–32 mm depending on the grade and age of the concrete as well as the strength of the fastener. yield crete. The ability to exploit this characteristic is also limited by increased fastener driving failure rate with higher strength concrete. As could be expected, the depth of penetration at which the failure rate is at a minimum decreases with increasing concrete strength. 1.58 11 / 2<strong>00</strong>7 Mean ultimate pullout Nu,m [kN] Average ultimate pullout Nu,m [kN] Depth of penetration h ET [mm] Optimal depth 0f penetration Average ultimate pullout N u,m [kN] Failure rate, p (%)
Concrete parameter The concrete parameters such as type and size of concrete aggregates, type of cement and the location on top or bottom surface of a concrete floor do affect the fastener driving failure rate, sometimes significantly. Fastener driving failures are caused by the fastener hitting a hard aggregate, such as granite, located close to the concrete surface. A hard aggregate can deflect the fastener and in a severe case, the fastener may bend excessively, leading to con- Overhead fastening is usually associated with a higher rate of fastener driving failure than floor fastening. This is due to the distribution of the aggregates within the concrete. Large aggregates tend to accumulate at the bottom of a floor slab. At the top, there is a greater concentration of small aggregates and fines. Concrete base material crete fracture in a cone shape and no hold obtained by the fastener. In case of slight fastener bending, concrete spalling may occur at the surface. However, because pull-out strength is obtained mostly in the area of the fastener point, concrete spalling does not affect the permissible load of the DX-/GX-fastening. Softer aggregates such as limestone, sandstone or marble may be completely penetrated when hit by the fastener. Top side Bottom side 11 / 2<strong>00</strong>7 1.59 Concrete placement
Page 1 and 2:
Principles and technique Introducti
Page 3 and 4:
Introduction Introduction 1 1.1 Def
Page 5 and 6:
? + ? + = 2.4 kN + + = 2.4 kN A com
Page 7 and 8: Hilti direct fastening systems are
Page 9 and 10: The direct fastening system Introdu
Page 11 and 12: 2.1 Fasteners The direct fastening
Page 13 and 14: Stainless steel fasteners Hilti int
Page 15 and 16: Hilti Tools All Hilti tools supplie
Page 17 and 18: The direct fastening system DIN 726
Page 19 and 20: Health and safety Introduction 1 Th
Page 21 and 22: Drop-firing safety The drop firing
Page 23 and 24: ystanders. Safety tests with carton
Page 25 and 26: Quality of installation The use of
Page 27 and 28: Corrosion Introduction 1 The direct
Page 29 and 30: 2. Contact corrosion Corrosion is a
Page 31 and 32: Hilti X-CR / X-BT stainless steel f
Page 33 and 34: Steel base material Introduction 1
Page 35 and 36: Fusing (welding) Complete fusing of
Page 37 and 38: Guide values for the depth of penet
Page 39 and 40: Steel base material Surface of the
Page 41 and 42: Steel base material Compressive str
Page 43 and 44: 5.5 Thin steel base material Steel
Page 45 and 46: Failure of the base steel If the th
Page 47 and 48: Pull-over test specimen at test beg
Page 49 and 50: X-CRM8-15-12 (stainless steel faste
Page 51 and 52: Steel base material 5.7 Effect of f
Page 53 and 54: 5.9 Effect on the fatigue strength
Page 55 and 56: Concrete base material Introduction
Page 57: Clamping The compressibility of con
Page 61 and 62: Edge distance and fastener spacing
Page 63 and 64: Masonry base material Introduction
Page 65 and 66: Temperature effects Introduction 1
Page 67 and 68: Base steel: S355K2G3 h = 25 mm fy =
Page 69 and 70: 8.3 Fire rating of fastenings to st
Page 71 and 72: Temperature effects 8.4 Fire rating
Page 73 and 74: Design concepts Introduction 1 The
Page 75 and 76: The characteristic strength is defi
Page 77 and 78: Determination of technical data Int
Page 79 and 80: 10.2 Profile sheet fastenings Deter
Page 81 and 82: Calculation method The calculation
Page 83 and 84: Determination of technical data The
Page 85 and 86: DX fastenings on concrete Fault Fas
Page 87 and 88: DX fastenings on steel Fault Nail d
Page 89 and 90: Approval Listing Summary of approva
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