This book includes a plain text version that is designed for high accessibility. To use this version please follow this link.
CONSTRUCTION FIXINGS


Anchoring in cellular concrete blocks


Doctors A.V. Granovsky PhD and D. A. Kiselev, from the TSNIISK Central Research Institute for Building Structures submitted this report on “Experimental investigation on bearing capacity of anchor fasteners installed into walls made from cellular concrete blocks”. It presents an interesting insight to some of the issues in the Russian Federation construction fixings market.


A


s of today, there is a heavy deficit of cellular concrete of good quality in the Russian Federation. Because of a shortage of quality products, consumers have to purchase concrete manufactured by makeshift working


methods, namely non-autoclave cellular concrete and aerated concrete. Considering the application of cellular concrete variants in the form of small-sized blocks in self-supporting walls, with separations by floors, for residential and public building, the absence of proper control of their strength and density leads to wide-scale usage of aerated concrete block - for example: with strength between 0.8MPa and 2.5MPa and density below 500kg/m3


. The aforementioned problem has


become the most challenging one in relation to the attachment of bearing substructures of façade systems to walls made of such materials, and with installation of metal reinforcing bonds in two- or three-layer walls. We would like to note that in 1982 experts from several


research institutes issued the State Standard GOST 25485-82 that clearly divides cellular concretes, depending on class of concrete and its density, into the following types: structural, structural and heat-insulating, and heat-insulating concrete. “Recommendations for application of small-sized wall blocks from cellular concretes”, issued in 1992 by experts from TSNIISK, NIIZhB (Research Institute of Reinforced Concrete) and LenZXIIEP (Leningrad Zonal Research Institute c Experimental Design), prohibited the use of cellular concrete blocks of the grade below 2.5MPa and with density lower than 500kg/m3


for


self-supporting walls. Unfortunately, these requirements are nearly forgotten today. At the same time, wide-scale usage of cellular concrete blocks, classified as belonging to structural and heat-insulating types, leads to a sharp reduction of service reliability of both walls and façade structures (including hinged ventilated façades) that are attached to the walls. Because of immensely increased volume of works for building hinged ventilated façades, the question of the reliability of fastening façade structures to the walls made of cellular concrete blocks becomes especially vital.


Selection of the most efficient types of anchorage used for fastening facade structures to walls made of cellular concrete blocks.


Experimental investigations for determining pull-out strength


of various types of anchors installed into walls made of cellular concrete blocks have been carried out at the TSNIISK. The objective of these investigations was to select the most effective types of anchors used for fastening façade structures to the walls made from cellular concrete blocks. Anchors from the companies fischer, Sormat, Mungo and Hilti, which are available in the Russian Federation market,


were chosen for testing. Tests of anchors with the objective of determining their pull-out strength were carried out in accordance with a technique developed by the TSNIISK. The compression strength class of concrete was B 1.2. Depending on their design the anchors were divided


into 3 sub-groups.


1) Anchors consisting of a working body in the form of screw (7mm diameter, length 105mm) and an insert – a polyamide plug (10mm diameter, length 100mm). Examples of this group of anchors include fischer SXR, Mungo MB-S, Sormat KAT N, Hilti HRD-UGS. Generally speaking these anchors differ one from another only by the profile of the polyamide plug and are recommended by their producers for installation into cellular concrete blocks. An example is shown in Figure 1.


Figure 1


2) Thread design anchors. These anchors have a polyamide spiral external thread that, using a setting tool, is designed to cut another thread into the base material. Examples of these anchors were only found from the companies fischer (FTP K10) and Sormat (KBT 10). An example is shown in Figure 2.


Figure 2


3) Chemical anchors consisting of the following elements: • Working body - thread stud 10mm diameter. • Injection resin. • Polyamide or metallic net-shaped sleeve.


This group includes anchors from fischer, (FIS V360 S),


Sormat (ITH 380) and Mungo (MIT-P). Example of a typical system shown in Figure 3.


80 Fastener + Fixing Magazine • Issue 68 March 2011


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164