HOW TO ANCHOR A BASE PLATE IN SEISMIC AREAS

Fastening systems for earthquake zones

Structural and non-structural earthquake damage

Earthquakes are much more common than we realise. They happen every day all over the world.

Not only do they cause loss of life and serious injury, but they can also do great damage to buildings and the economy.

All this can be limited by good seismic construction design and specification.

It’s important to include seismic design for both non-structural and structural elements of a build, as research shows that non-structural systems suffer the largest damage in commercial buildings during an earthquake.

HOW ANCHORS BEHAVE IN AN EARTHQUAKE

Seismic conditions significantly change the behaviour of anchors, compared to static conditions.

HOW HILTI ANCHORS COMPLY WITH SEISMIC CODES

Seismic design requires designing for seismic categories C1 or C2.

The European Organisation for Technical Approvals (EOTA) TR045 states most of the applications only allow the use of category C2 anchor systems for seismic areas.

At Hilti we produce a range of anchors, which are code compliant and fit seismic performance category C2.

Relevance in Australia

The earthquake hazard map in AS1170-4:2018 shows the acceleration coefficient for different locations across Australia. Seismic design is relevant in large parts of the country, represented on the map.

SEISMIC PERFORMANCE RELEVANCE TO ANCHOR CONNECTIONS

In Australia seismic category C2 is required in most cases for structural elements due to the ground acceleration zones mentioned earlier. Seismic category C2 is also required for non-structural elements for high importance buildings and high ground acceleration zones.

Whereas for buildings with a low importance class in low ground acceleration zones seismic category C1 is required.

HILTI ANCHORING RANGE WITH SEISMIC APPROVALS

HOW DO I DESIGN ANCHORS FOR SEISMIC AREAS

At Hilti our engineering team can help you design your anchor systems – just contact your local office for more details.

Or, you can use our Hilti PROFIS Engineering software. This includes code compliant Hilti products in 2D and 3D with relevant documentation and specifications.

Our PROFIS Engineering software performs seismic calculations according to EOTA TR 045. This gives three solutions for anchoring base plates in seismic areas:

Capacity design

The anchorage is designed for the force corresponding to the yield of a ductile component, or if lower, the maximum force that can be transferred by the fixture or the attached element.

Elastic design

The fastening is designed for the maximum load assuming an elastic behaviour of the fastening and of the structure.

Design with requirements for anchor ductility

This design for ductile steel failure requires an anchor classified as ductile. This approach is also applicable only for the tension component and some provisions need to be observed to ensure that the cause of failure is steel failure.

We’ve also added our own Hilti research results into PROFIS Engineering software, so that you can find solutions, which go beyond EOTA TR 045.