Wall Tie Testing and Spacing
Remedial tie testing
Testing may be included as a routine part of the process of specifying and installing Helifix remedial wall ties.
During installation, a random number of ties may be tested at different levels and elevations to determine the pull-out load from the substrate materials. Pre-specifiction testing may also be included as a part of the survey of the building, with the identified pull out loads used to determine the density of ties to be fitted.
Pull-out tests on Helifix ties can be easily and accurately conducted on site using the Helifix Load Test Unit.
Load requirements will typically vary from one site to the next. However, as a general guide, it should be noted that wall ties are load sharing devices and that specifictions demanding high point loads are to be avoided as these can lead to sudden failure.
The current Australian Standard for masonry structures (AS3700—2001) generally recommends that cavity and masonry veneer wall ties be spaced at not more than 600mm centres (vertical and horizontal) in unbroken masonry faces and not more than 300mm centres around openings.
Geography, building type and wind exposure classification can all influence spacing requirements, however, and in some situations, a full site survey conducted by an engineer may be required to produce an accurate specification.