DBIA IQ Summer 2012 - (Page 17)

prefAB//stAte of the sector By Brian Miller, pE, LEED ap Most DesIgNers, coNtrActors and owners have heard of precast concrete, but not all are familiar with its versatility as a building system or the latest innovations in precast concrete technology. That’s why it is important to involve precasters and other specialty subcontractors as early as possible. Precasters make great design-build partners. They help optimize a project, from design and performance to cost and scheduling. Involving precasters early allows for more interaction with the design-build team, when they can share their experience and expertise to save time and money. Some of the areas that precast concrete can improve upon in a design-build project include construction time, energy performance and functional resilience. Precast concrete is one of the fastest building systems available. Manufactured off-site, it enables other tasks such as excavation and foundation work to move ahead at the project site. Once a foundation is set, precast concrete systems can be delivered and erected quickly by a relatively small crew and crane, speeding enclosure. This requires little space and minimizes negative impact at the site, which has become important for sustainability. When structures are built in half the time, as compared with other construction systems, everyone wins. To meet the high-performance requirements of today’s structures, such as increased energy efficiency and functional resilience, precast concrete is a great option for a building’s envelope and structural systems alike. Precast concrete insulated envelope systems provide high R-values by supplying continuous insulation and thermal mass. Concrete absorbs and releases heat slowly. High heat capacity greatly improves the thermal performance of a building. If the precaster gets involved in the project early and works with the HVAC designer and contractor, the increase in the building’s thermal performance can yield as much as 30 percent more energy efficiency than current codes require. Another consideration is a structure’s functional resilience, or its ability to withstand natural disasters such as tornadoes, hurricanes and earthquakes, as well as man-made incidents such as terrorist attacks. Structures must be designed and built to protect occupants during these events and must be able to return to full functionality quickly in the aftermath. Because precast concrete works well as a structural system, it protects occupants while maintaining a structure’s functional resilience. In most cases, a precast concrete building strategy incorporates the envelope system, reducing the need for additional materials to clad a structure. The inherent strength of precast concrete provides passive fire resistance and excellent resistance to the high winds and flying debris associated with tornadoes and hurricanes. It also suffers no negative effects from long-term moisture exposure. Extensive research on seismic and blast design in recent years has sparked the increased use of precast concrete in seismic zones and military and government structures, which have antiterrorism force protection requirements. Precasters can work with design-build teams to make sure the latest advances in precast concrete are considered and incorporated into design-build projects whenever appropriate. Precast concrete can help deliver efficient, strong and secure buildings on time and within budget. dbia.org / PREFAB REPORT summer//2012 17 precast concrete helps Meet high-performance Demands http://www.dbia.org

Table of Contents for the Digital Edition of DBIA IQ Summer 2012

DBIA IQ Summer 2012