Anchors masonry

Anchoring systems are materials used mainly for securing bolts, bars, tendons or dowels in drilled or formed holes in concrete, masonry or natural rock. Polyester anchors are widely used because of their fast curing property and high early strength (Fosroc International, undated a). Epoxy anchors are applied in areas where there is a risk of alkaline hydrolysis. 

Anchoring grout controllable setting time rapid strength gain corrosion resistance Securing bolts, bars, tendons or dowels in drilled or formed holes in concrete masonry or natural rock... 

Anchor bolts- Bolts to secure a wooden sill plate to concrete, or masonry floor or wall. 

Sill plate- A horizontal member anchored to a concrete or masonry wall. 

Figure 4.28 shows the seismic upgrading of the masonry shear walls of a school building in Bern, Switzerland. GFRP fabrics were glued to the surface of the walls followed by CFRP strips, which were applied crosswise on the GFRP fabric layer. The strip ends were anchored in the RC decks... 

Seismic retrofitting of a masonry shear wall using GFRP fabric and additional CFRP strips, which are anchored in concrete using end plates school building at Zollikofen in Bern, Switzerland (from Motavalli and Czaderski 2007). 

Fig. 6.27. Fixing of resin bonded anchors to masonry (courtesy of Hilti Ltd).

There are two basic methods by which steel bolts and bars may be anchored into concrete, masonry or brickwork utilising epoxy or polyester resin grouts(5). The first involves inserting a deformed bar or bolt into a preformed or drilled hole into which the resin grout has been poured (Fig. 7.3). 

Resin anchors are quite widely used already for fixing steel bars and ties in concrete and masonry structures. A concept marketed... 

Fig. 9.11 (a) Borehole drilling for steel anchor connection betwetai masonry and roof (b) application of textile layers in vertical oii tation... 

In the case of a debonding involving the first layers of the masonry and with anchor lengths equal to or larger than the optimum length, the factored tensile stress within the reinforcement, that is, the value of the maximum tensile stress at which the reinforcement can work on the ends of the anchor section, once the transfer of stresses from the masonry to the FRP reinforcement has taken place, is as follows ... 

In the case of masonry panels undergoing stresses over the panel plane, resistance to combined compressive and bending stress over the panel plane can be enhanced by vertically and synunetrically laying np reinforcanents with composite materials over the two faces of the masonry panel and by anchoring them to the end sections of the panel. 

The structural masonry member confinement should be carried out with the help of fabrics, sheets, and bars (otherwise called ground anchors) of composite material. Fabrics are applied on the contour as external continuous wrapping or discontinuous wrapping the bars are arranged inside the column, in order to realize suitably widespread reinforced stitches. 

With regards to the connection of wallboards to masonries, a number of studies have experimentally shown that, besides the adhesion by resin, a further mechanical anchoring is recommended, which can be obtained with composite or metal material. 

A Vs-in. thick preformed plain elastomeric pad or fabric pad placed atop the concrete bearing surface or grout pad most economically compensates for any minor surface irregularities. Fully threaded anchor rods can be either cast into the concrete or drilled and grouted into place. An anchor plate can be either bolted or welded to the bottom of the anchor rod to augment uplift capacity in the concrete. If no uplift capacity is required, a swedged rod may be substituted for a threaded one. The swedged rod may be terminated just below the top of the masonry plate and the void filled with a flexible sealant. 

Currently, qualification methods based on experience are available primarily for seismic design and seismic re-evaluation of equipment [37-39]. Earthquake experience methods are simple and efficient tools to verify the seismic adequacy of selected mechanical, electrical and instriunentation and control equipment classes. Earthquake experience methods are also used to verify the seismic adequacy of piping, anchoring of piping supports and masonry walls, and to check potential seismic interactions. These methods are primarily screening and waUcdown procedures and are summarized in Appendix III. Some of them involve establishing the similarity of candidate items to reference items. Similarity requires both the following basic conditions ... 

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