EN 846-5-2012 pdf download.Methods of test for ancillary components for masonry – Part 5:Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (couplet test).
5.4 A test machine capable of applying the load without distortion such that the maximum load reading occurs above 20 % of the full scale reading.
The load shall be measured using a load cell device having a digital or analogue readout with a maximum error of 2 % of the full scale reading. The system shall apply an axial force to the specimen. The system or universal test machine shall be fitted with a rigid connection between the clamp which is used to apply tension or compression loads and the machine cross-head or loading device, i.e. any pivot ball joint or universal joint connections to the load cells shall be locked.
5.5 A means of measuring displacement of the couplet in relation to the clamp using at least two symmetrically placed dial gauges or electrical linear displacement transducers as shown In Figure 1.
Displacement shall be measured to the nearest 0,01 mm.
Displacement shall not be measured by recording the cross-head travel of the test machine.
5.6 For polymer-based (plastics) products only, a controlled temperature and humidity
chamber or room which may be a chamber which fits over the specimen. 6 Preparation and storage of test specimens
6.1 General
Ten couplet specimens each for compression and tensile testing shall be prepared with the ties embedded to the declared minimum embedment length. The number of specimens for each shall be doubled where both ends of asymmetrical ties are tested separately.
6.2 Preparation
Build the specimens on a flat horizontal surface, and lay the ties in the bed joints between two masonry units by normal bricklaying techniques, using a jig to ensure axial alignment of each tie. A typical jig is shown in Figure 4. Align the two stretcher faces to be used for reaction to give a plane surface. Strike off the mortar flush with the faces of the specimen.
General purpose and lightweight masonry mortar joints shall be between 8mm and 15mm thick. Thin layer mortar joints shall be between 1 mm and 3 mm thick.
Record the position of the ties in relation to any perforations, frogs or other depressions of the bed face of the units.
Deviations from axiallity of the tie in a couplet is liable to reduce its measured strength. This effect may be assessed by measuring the compressive strength of offset ties in a suitable test machine.
6.3 Length of embedment of ties in mortar beds
For symmetrical ties, physically identical at each end and designed or intended to be used in mortar at each end, the length of embedment shall be the declared minimum embedment length.
For asymmetrical ties either of a different physical design at each end or designed or used in different materials at each end, the length of embedment shall be the declared minimum embedment length for each end.
In each case, record the length of mortar beyond the embedment length.
6.4 Storage
Take appropriate steps to prevent the test specimen from drying out during the first three days after construction, e.g. by covering with polyethylene sheets, and then leave uncovered in a laboratory environment until tested. Use a curing period of 7 days for thin layer mortars and 28 days for general purpose mortars
7 Procedure
7.1 SettIng specimen In test machine
At the end of the curing period:
a) Load the specimens into the test system or test machine such that the tie body is axial and aligned at the centre of the test machine where no movement tolerance or slope tolerance Is specified for the particular tie system;
or
b) In cases where slope tolerant or movement tolerant ties are required to be tested offset one end of the specimen over a distance which gives the maximum slope or half the maximum movement specified by the manufacturer and repeat this in both directions fifty times. After this offset one end of the specimen from the centre of action of the test machine or test system by a distance which gives the maximum slope or half the maximum movement specified by the manufacturer.
When testing in tension the clamp may be applied to the tie at a distance from the couplet equal to the cavity width at which the tie is intended to be used. When testing in compression the clamp should be applied at a distance from the couplet equal to the cavity width at which the tie is intended to be used pIus 15 mm. Alternatively where the resistance of the anchorage is to be determined separately from the section which bridges the cavity the damp should be placed close to the face of the couplet. In the case of compression testing a gap of approximately 5 mm is required. The distance from the damp to the face of the couplet should be measured and recorded.EN 846-5-2012 pdf download.