New Zealand Commercial Design Trends Series NZ Commercial Design Trends Vol. 30/9 - Page 35

Where conventional analysis fails New buildings are designed to the Building Code to ensure they behave – and even fail – in a predictable fashion. But existing buildings may behave unpredictably according to both stiffness and the strength of their elements, many of which were never designed to resist seismic loads. Building analysis tools used on new structures are seldom sophisticated enough to be able to predict what happens when parts of the building are overloaded. But stopping the analysis at that point will often not detect issues which may be more critical to the survival of the building and its occupants. That can lead to very conservative strengthening solutions, or even unsafe systems if the resulting strengthening isn’t compatible with the building’s natural behaviour. Interim securing – a short-term solution Typically, one of the main vulnerabilities of heritage buildings is their lack of structural connectivity – all that holds them together is often just gravity and friction between the elements. Earthquakes have a way of finding these weaknesses and shaking the building apart. In cases where a suitable strengthening solution cannot be SEARCH | SAVE | SHARE AT 33