Structural Durability: Steel Framework vs. Other Materials
Load Bearing and Industrial Stress Handling Capacity of Steel Prefabricated Warehouse Systems
With regard to handling weight and managing space within a warehouse, steel framing systems are superior to older materials. Steel outperforms reinforced concrete in weight to strength ratio by \~5 ipfm according to FEMA studies dated 2023. Steel constructions can provide column free spans of over 300 feet, increasing available space for warehouse managers. Moreover, steel constructions provide ~40% less locations of stress and traffic related failure points. In steel constructions, one of the most important factors is the behavior of steel in a seismic event. Steel's yield strength is typically between 50 - 65 ksi, and therefore, steel constructions are less susceptible to collapse in a seismic event, unlike wooden or brick constructions. According to NCSEA, traditional materials flex dangerously at ~30% of the load they are designed to carry. This fundamental difference justifies the use of steel constructions in seismic and earthquake risk zones.
Comparative analysis of the resilience of galvanized steel, reinforced concrete, timber, and masonry in the context of warehousing
The longevity of a warehouse dependent on the choice of material in regard to the three resilience metrics below.
In contrast to the concrete, which is prone to chloride-induced corrosion, timber, which is prone to the corrosion, timber’s vulnerability to moisture, rot, and pest damage also requires three times as many structural inspections as in steel-framed warehouses in accordance with the maintenance guidelines of IS0 15686.
Environmental and Hazard Resilience of Modern Prefab Warehouse Structures
Steel warehouses constructed on-site provide excellent structural protection and functionality in any environment due to their excellent engineering design.
A steel warehouse that has been prefabricated on-site with off-site construction can be engineered to provide protection from corrosion due to thermal cycling and weatherproofing in a high-humidity environment. The galvanized steel framework of the warehouse withstands corrosive damage from sea salt sprays for 50+ years. Custom weather seals prevent rain from penetrating the steel fabric of the building. As humidity increases, thermal breaks due to condensation from moisture are prevented. Steel has a low rate of thermal expansion (7 millionths per ˚F). This provides the structure with stable dimensions in a temperature range of -40˚F to 120˚F. The stable dimensions reduce the wear on joints and prolong the life of the building less maintenance on the building. Real-life evidence supports the warehouse managers in coastal locations and independent test reports that maintenance costs are approximately 40% lower than for traditional building constructed warehouses.
Fire Rating Compliance, Pest Control, and Seismic
Wind Load Design Considerations for Prefabricated Steel Warehouses
Modern prefabricated steel warehouses offer high degrees of fire resistance that far exceed standard building code requirements. Because the steel used to create the warehouses does not burn, the warehouses receive the highest fire rating available without the need for chemical treatments. Additionally, the steel panels used to construct the buildings are tightly interlocked, leaving no entry points for pests. Steel warehouses are built with frames that are engineered to meet the latest ASCE 7-22 requirements, making them capable of withstanding seismic acceleration up to 0.3g and wind speeds exceeding 150 mph. The design of the warehouses also reduces the upper lifting forces by about 25%, improving performance in storms based on wind tunnel testing. These increased performance ratings result in lower operating costs for property owners. Insured claims data indicates that prefabricated warehouses are 30% less likely to result in an insured damage claim compared to other types of warehouses built in the same geographical area.
Long Term Lifecycle Value: Maintenance Flexibility, and Total Cost of Ownership
30-Year TCO Perspective: NIST and NCSEA Data on the Durability of Prefab vs. Conventional Warehouses
Recent studies from NIST and NCSEA illustrate that for the first three decades of operation, maintenance and adaptability costs of newly constructed warehouses using conventional building methods versus those employing prefabricated steel (PS) construction methods are approximately 20 to 30 percent less than those using conventional building methods. Why is this the case? The primary reason is that galvanized steel, the primary construction material in PS warehouses, does not rust and therefore eliminates the need for the expensive chemical treatments that are required for the wood and steel (and steel-composite) components of conventional warehouses. Moreover, the modular and flexible design of PS warehouses allows for easy expansion, avoiding expensive retrofitting for tenant changes or expansions, compared to conventional warehouses constructed of wood and brick which require continuous maintenance and repairs from the damaging effects of pests, water and fire, leading to increased expenditures of 15 to 25 percent in contrast to PS warehouses. After standing for 30 years, the majority of the structural framing of steel (the most recycled material) in PS Warehouses will still be capable of supporting 95% of its original design load, in stark contrast to the classical compositions of open web metal joists which can be less than 70% and in many cases no more than 50% of their original load. Lastly, the energy efficient insulation and the efficient heating system used in PS warehouses provides a 18 to 22 percent reduction in heating costs compared to conventional construction (using wood) insulation and heating system. When considering all of these, the retrofitting of existing buildings and the construction of new conventional warehouses are ultimately a poor choice compared to the purchasing of prefabricated steel warehouses.
What advantages do steel frames have for warehouse construction compared to more conventional methods?
When compared to more conventional methods like wood and masonry, steel frames are less expensive to maintain because steel is also more economical in span situations where less support is needed, and in situations where seismic movement is present, steel possesses a greater strength, ductility, and overall performance.
Why is galvanized steel more advantageous in a warehouse setting that is humid or near the coast?
Galvanized steel has a long service life in steel and moisture conditions because the zinc coating, known as galvanized steel, is sacrificial and defensive corrosion generally starts with the exposure to moisture and salt.
What about prefabricated steel construction as it relates to fire and pests?
Steel as a construction material has a high rating for fire and pest resistance, and as steel construction is now treated with fire retardant chemicals, this is the case because the material does burn, and because pests cannot eat metal, steel construction has a high rating because the panel and frames can be pest resistant.
From an investment standpoint, is using prefabricated steel construction a good idea?
Prefabricated steel construction provides less investment risk over time due to less maintenance required as steel retains its integrity, and as compared to traditional construction, metal with a traditional construction means that steel construction provides less risk as it is adaptable as business needs change requiring fewer costs for retrofitting.