By Rear Adm. Maria Aguayo, P.E., CEC, M.SAME, USN, and Kristin Brennan, P.E., M.SAME
The U.S. Navy takes an all-hazard approach when it comes to resiliency in criteria, climate change, natural disasters, new weapons and platforms, adapting to changes in building code, and new threats from adversaries. The overarching goal is to build and maintain resilient installations that support the warfighter and ensure the capability to prepare, protect, and, when necessary, recover from extreme weather events.
Recently, the Eastern Seaboard of the United States has endured an increase in severe storms, hurricanes, and tornadoes. In 2018, Hurricane Florence made landfall in North Carolina near Marine Corps Base Camp Lejeune and Marine Corps Air Station Cherry Point, bringing damaging winds and devastating floods that measured 36-in of rainfall. The storm caused catastrophic damage to more than 800 facilities and over $2 billion in unbudgeted repairs.
In the aftermath of Hurricane Florence, Naval Facilities Engineering Systems Command (NAVFAC) has continued to apply lessons learned by institutionalizing modifications to current design standards or construction practices through updates to Unified Facilities Criteria (UFC).
PROTECTING AGAINST EXTREME WEATHER
When planning for new facilities on naval installations, NAVFAC is challenged with locations that are mostly in areas close to the ocean, around the Pacific Ring of Fire, or remote sites distanced from redundant resources. Occasionally the fleet’s mission restricts siting in desirable areas, so designers and planners instead mitigate risk by increasing design standards where applicable.
In some ways, UFCs are more stringent than model code provisions. This is evident in how wind loads are calculated on aircraft hangars, restrictions on the use of vertical lift fabric hangar doors, and testing requirements on roll-up doors and sectional doors in hurricane-prone regions. The goal is to provide better protection of high value assets and mission-critical facilities. NAVFAC also has expanded criteria associated with windborne debris regions to cover high-value assets at various defense installations, specifically requiring protection above industry standards.
Following analysis of the damage from Hurricane Florence, UFC 3-301-01, “Structural Engineering,” now contains additional protection against wind and windborne debris—identifying facility risk categories based on mission criticality and protection of high value assets. These design requirements provide appropriate risk levels as well as resilience from extreme weather events and impacts.
Additionally, NAVFAC has imposed the State of Florida’s testing and certification requirements on all roll-up doors in hurricane-prone regions. Doors now must be tested to ANSI/DASMA 108. Most importantly, NAVFAC has eliminated outsourced design of specific structural elements and instead requires them to be designed by the engineer-of-record for greater accountability.
Hurricane Florence resulted in many high value assets being condemned, including mission-critical aircraft hangars. The rebuild program includes 200 facilities that all observe the new codes and standards. The new CH53K hangar at Marine Corps Air Station New River, currently under construction, features almost 300,000-ft² of maintenance spaces, 600 aircraft parking spaces, and a 527,000-ft² aircraft apron.
PLANNING & DESIGN CRITERIA
True facility resiliency is only achieved when design and construction is married with planning, sustainment, and response. UFC 2-000-05N, “Facility Planning Criteria for Navy/ Marine Corps Shore Installations,” identifies facility planning criteria in order to ensure proper planning, space allocation, and basic facility requirements intended to meet mission assurance and mission-essential functions. These efforts aid in the accuracy and timing of programming and budgeting for the military construction program and align planning with design requirements addressing resiliency.
Geotechnical considerations are currently under review as well for utilities and facility infrastructure due to an increase in seismic activity and the structural failure of mission-critical facilities on Naval Air Weapons Station China Lake, Calif. In 2019, China Lake was the epicenter of two earthquakes measuring 6.4- and 7.1-magnitude that caused up to 15-ft ground displacements and $1.5 billion worth of damage to facilities and infrastructure.
Of note, the resilient performance of newly constructed buildings during the China Lake earthquake events were comparatively more successful in resisting structural damage due to the adoption of more stringent building codes. Older facilities and utilities on the base were significantly more likely to be condemned or found structurally unsound.
NAVFAC recently updated Facility Criteria 3-220-01N, “Soil Mechanics (NAVFAC DM 7.1),” which will be published as UFC 3-220-01, and is in the process of updating DM 7.2, “Foundations and Earth Structures,” as a companion document. These are valuable legacy documents in the geotechnical engineering community and are used widely inside and outside of the Department of Defense as references. These manuals contain correlations to estimate engineering properties of soil, rock, and deep and shallow foundation design that have widespread use in the civil, geotechnical, and structural communities. New content in these documents will include a focus on engineering correlations, numerical modeling, problem soils, and reliability.
ADDRESSING SEA LEVEL RISE
Climate change constitutes more than natural disasters. At Naval Air Station Sigonella, Italy, for instance, what would have been identified 15 years ago as an isolated storm is now a more frequent occurrence as rising sea levels have increasingly contributed to flooding events in coastal regions. UFC 3-201-01, “Civil Engineering with Change 5,” incorporates sea level change to increase accuracy in flood projections used in the planning and design phases. Current guidance aligns with recent National Defense Authorization Act stipulations for establishing Design Flood Elevations for facilities by using a comparison approach of freeboard instead of DOD Regional Sea Level requirements coupled with facility mission criticality.
Changes to UFC 2-100-01, “Installation Master Planning,” address climate change and sea level rise. Specific updates instituted the use of the DOD Regional Sea Level database for sea level change and include the use of the DOD Climate Vulnerability Assessment Tool. Additionally, the NAVFAC Climate Change Planning Handbook – Installation Adaptation and Resilience provides the analytical framework and methodology to help Navy master development planners consider climate change in their plans and projects. The handbook is a desktop reference and serves as a companion tool throughout planning, especially the analysis phase of the Navy Installation Development Plan process.
Energy resiliency is critical to effective planning and design. The NAVFAC Public Works Team is working to establish guidance on energy best practices and microgrids and is leaning forward in preparing infrastructure for electric vehicles. The path to greater resiliency includes improved energy security. Our Public Works enterprise is credited with the development of NAVFAC P602, a document geared to standardize energy security performance benchmarks across the Navy. Its planning methodologies provide consideration for system reliability, resiliency, and efficiency. Converting this document to a facility criteria will help ensure the incorporation of its core values into all Navy energy projects.
Furthermore, NAVFAC is incorporating the NAVFAC P601, Microgrid Design Guide, into the “Microgrid Design” UFC, initiated by the U.S. Army Corps of Engineers. This design guide establishes a microgrid tool for planning and design, and provides installations with a basic understanding of microgrid technology and a common methodology to identify requirements and develop conceptual designs.
Meanwhile, the NAVFAC Environmental Team has had success with nature-based solutions to aid in the reinforcement of its extensive shorelines. NAVFAC continues to expand this effort by partnering with the tri-service community to share ideas, research, and work on advancing criteria and resiliency in these areas. NAVFAC and its subject matter experts are working collaboratively with the Army Corps of Engineers and the Air Force Civil Engineer Center on the development of a “Natural and Nature-Based Features” UFC. This document would assist planners and designers to scope out and develop nature-based solutions to add resiliency to the overall utility structure installation of individual projects. While environmental specialists have successfully implemented natural and nature-based features, this UFC intends to help planners and designers incorporate its principles on all future projects when applicable, with a particular focus on mitigating flooding and storm damage.
While all these lessons learned are applicable to new design and construction and have met desired outcomes for resilient infrastructure, aging facilities present challenges, as they statistically fare the worst under climate change stressors. NAVFAC is currently investigating industry standards on inspection of high occupancy and mission-critical facilities to re-evaluate existing building repair over replacement triggers, as well as methods to enhance facility inspections. With limited funds, decisions to repair or replace an older structure should balance total lifecycle costs, resiliency, life safety, and mission assurance concerns.
By leading from the front in implementing new planning, design, construction, and energy criteria, NAVFAC is swiftly adapting and adjusting with increased trust in the lifespan of facility construction in this increasingly changing environment.
Rear Adm. Maria Aguayo, P.E., CEC, M.SAME, USN, is Commander, NAVFAC Atlantic and U.S. Fleet Forces Civil Engineer, and Kristin Brennan, P.E., M.SAME, is Geotechnical Engineer, NAVFAC Atlantic. They can be reached at firstname.lastname@example.org; and email@example.com.
[This article first published in the November-December 2021 issue of The Military Engineer.]