New construction for resilient cities: The argument forsustainable low damage precast/prestressed concrete building structures in the 21st century

Abstract. Thoughtfully chosen, properly designed new construction can signicantly improve both the resilience to natural and man-induced disasters and the long-term sustainability of modern urban environments in the 21st century. In particular, precast/prestressed concrete construction has the ability to provide low-damage buildings at similar costs to traditional construction while also providing a more sustainable construction form, in terms of higher energy eciency and lower embodied energy. In this paper, low-damage sustainable precast concrete seismic systems are described. Prestressing leads to less material required and hence less embodied energy; piece erection leads to cleaner, quieter construction sites; and insulation and architectural nish can be integrated directly into the precast unit, increasing energy eciency, and consolidating construction operations. With respect to resilience, earthquake damage is avoided by taking advantage of the inherent jointed nature of precast concrete construction, thereby promoting opening of gaps between precast units rather than cracking of the concrete itself, and using unbonded post-tensioning concepts to restore the structure to its original position. The potential use of precast concrete in developing countries, where no precast industry exists, is considered in the context of global sustainability. The performance of precast concrete in recent earthquakes is presented as an example of a resilient construction.