Resilience and the National Model Building Codes
Resilient building design is increasingly being considered by owners and builders in communities and cities across the nation. National model building codes set the baseline for the safe design and construction of homes, schools and workplaces, providing minimum requirements to adequately safeguard the health, safety and welfare of building occupants. Resilient building design goes beyond the code minimum requirements and considers the financial and societal costs of operational disruption in the wake of disasters.
Designing and upgrading buildings with the ability to maintain operations or quickly bounce back after disasters, whether natural or man-made, is becoming increasingly important. It is not enough to have a building simply withstand an unexpected event; whether it’s a hurricane, earthquake or blast, if that building is not safe for immediate occupancy, is not functional, or is not quickly repairable and able to be put back into service. The industry is looking to construct buildings and other critical infrastructure that can sustain minimal damage and suffer little-to-no disruption following a disaster.
The predictable performance of steel when subjected to the structural loads and movements imposed by natural hazards and man-made events, due to its homogenous and isotropic properties, provides the design professional with the necessary information and ability to design. Steel is an inherently stable, manufactured material with consistent chemical and mechanical properties. Once a steel member has been formed, it will remain stable with virtually no change to the thickness, width or other dimensions, as well as strength and stiffness. Likewise, fasteners, connectors and welds used to join steel framing members retain their strength and reliability over time.
The strength, ductility and durability of steel construction products allow buildings to withstand high forces and deformations that accompany events like earthquakes or blasts. In addition, steel is noncombustible. Fires can follow disasters and since steel products will not contribute to the spread (e.g. fuel load) of a fire, steel-intensive buildings are less likely to sustain devastating fire-related damage.
Steel also provides opportunities for easy repair and/or replacement after a natural hazard or man-made event. Steel's inherent resilience as a material, coupled with purposeful design decisions addressing resilient requirements, can address the owner's desire to maintain select building functions after a disaster.
Resilient building design begins with adoption and enforcement of up-to-date national model building codes. Adoption of modern national model building codes and adequate enforcement of those codes play a vital role in public safety and loss prevention. In addition to saving lives and reducing property loss, state and local building codes based on national model building codes provide consistent requirements for design professionals, suppliers and builders, creating a minimum standard upon which consumers can rely.
Resilient building design does not merely use existing methods with higher loads. Resilient building design requires consideration of new performance objectives. Reacting to demand from both the public and private sectors, performance-based design codes and standards are being developed to provide methods for achieving resilient building design.
The steel industry is taking a leading role in the national trend towards resilience by supporting the adoption of the most recent editions of national model codes and providing guidance to ensure building owners are aware of the steel building systems available for improved resilience so they can make informed decisions. Steel standards are updated regularly, giving design professionals and builders the information needed to ensure resilience is built into their building or rehabilitation projects. Steel’s durability, strength and ductility help steel-intensive buildings remain standing during catastrophic events and allow for continuous performance following disasters.
As the impacts of natural and man-made disasters increase, the industry needs to rapidly address and integrate the economic benefits of building resiliently and sustainably, both in the public and private sectors. While they are separate considerations, resilience and sustainability do have some connections, such as the reduced need for demolition and landfilling building products when structures can be occupied or immediately repaired in the wake of potentially catastrophic events.
Today many resilient codes and standards are developed as alternative methods, for selection by building owners depending on their risk tolerance and the critical nature of their buildings. However, building resilience is increasingly being mandated through regulation and legislation at the federal, state and local levels. This is happening at the national level for federally-owned buildings, and with cities such as New York City, San Francisco and Los Angeles. The impact of non-operational structures after extreme events may force a building owner or tenant to cease operations, but it also represents a significant financial loss to jurisdictions that can experience a reduction in the tax base as well as a general loss of economic vitality.
One example of this trend is the American Society of Civil Engineers’ (ASCE) standard for Seismic Evaluation and Retrofit of Existing Buildings. This standard, ASCE 41-17, is taking steps to address regional resilience concerns by giving builders and engineers a tool to evaluate buildings and look for potential issues within existing buildings.