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Page 26 — Multifamily Properties Quarterly — May 2022 www.crej.com Construction A ll buildings, no matter what their purpose, design or intention, have one top pri- ority: protecting the lives and health of the occu- pants. Smart design and the selec- tion of durable, high-performance materials go a long way toward cre- ating safe spaces. The past several years have seen a huge increase of severe weather events, fires and floods. Owners, designers and communities must design for and expect more from their buildings. When thinking about skyrocketing housing demand and multifamily construction, we need to consider not just the physical life of those inside, but also the daily lives, liveli- hoods and lifestyles of those who inhabit that building, as well as the community around it. The resilience of buildings and their surrounding infrastructure has become increas- ingly central to the conversation in design and construction. To prop- erly serve the owner, occupants and community, a building must do more than just withstand a fire, flood or storm. It must be able to return to usable function soon afterward. To meet these require- ments, more designers and builders are opting to use precast concrete. Precast components provide cost- effective solutions, along with the standard benefits of durability, ver- satility and resiliency. These struc- tures offer unsurpassed benefits for meeting the growing multifamily market segment by fortifying the demand for high-quality products with built-in safety features and quick build schedules. Precast concrete is specified for multifamily proj- ects for several other reasons as well. Multifamily precast compo- nents generally require elevated floors, high load capacities, open spans and large bays in the park- ing facilities. Precast components, including podium slabs, double tees, columns, beams, stair and elevator cores, walls and hollow core are used to construct parking levels, providing structural support as a base for upper-level residences. Using precast products creates long spans that open space and create design efficiency. Precast products are capable of acting as both struc- tural and architectural elements, meet demands as load-bearing ele- ments, provide high load capacities, and enable integration of structural, architectural and insulated precast products into one cohesive building system. With fires becoming more preva- lent than ever before, and creating huge dangers to the safety of occu- pants, buildings and communities, designers choose precast for inher- ent fire safety benefits. A nonflam- mable, noncombustible material, precast concrete is a natural fire inhibitor. Its use in structural and architectural design can be a real benefit to compartmentalization efforts that help contain fires and allow occupants to exit safely. A design approach stressing compart- mentalization offers a more funda- mental method to protect lives and property since compartmentaliza- tion uses passive, noncombustible floors and walls to construct sec- tions of the building as separate modules that confine fire to a spe- cific area. Once constructed into the building, these passive protectors will protect the building throughout its life. When dealing with fire resistance/ endurance, it’s necessary to under- stand the benefits of materials incorporated into the project. There are several codes that must be met, and designers should understand which materials meet the regula- tions for the structure while provid- ing economic benefits at the same time. Using precast can include the benefits of needing no special coat- ing or treating for fire resistance, lower insurance rates, larger allow- able gross project area and the important factor of occupant life safety. Wind force from tornadoes and hurricanes also can challenge the integrity of buildings. Precast con- crete has proven effectiveness and resilience against windborne debris that is hurled by direct wind speeds of up to 250 mph, equaling an EF5 rating. Precast designs can meet Federal Emergency Management Agency requirements for occupancy density, debris missile impact and suction, so it often is selected for use in community safe rooms. A precast safe room system can be added to many multifamily/park- ing plans as it is composed of struc- tural concrete walls. Wall panels are designed for high lateral loads, with a lateral load system consisting of floor and roof diaphragms transfer- ring lateral forces to precast con- crete shear walls, and down to the foundations. Community safe room systems designed to specific FEMA 361 standards create stability and safety with precast shear wall pan- els. In addition to the primary wind resistance they provide, the safe room walls also act as exterior load- bearing walls in some locations. The safe rooms should be built as indi- vidual units to exist without struc- tural support from the surrounding building for easy access for these climactic events. In these projects, special consid- eration is given to the connection requirement for the primary roof members, metal decking and struc- tural topping. Embed plates can be designed for gravity and uplift, with specific size to accommodate field tolerances, wall panel base connec- tions transfer uplift, overturning and shear requirements into the foundation. Specific considerations for topping and uplift of roof mem- bers are also implemented into the design of the precast panels for Precast offers life safety and resilience features Jim Schneider, LEED AP Executive director, PCI Mountain States Please see Schneider, Page 30