About the author ⁄ Scott Russell, S.E., P.E.

Scott Russell is the Manager of the Innovation Services Group, Nucor, Norfolk, Nebraska (scott.russell@nucor.com).

Sustainability and Beyond

The Untold Life Cycle of a Steel Joist

The attributes of open web steel joists are well known to the structural engineering and construction community. Their efficiency, high strength-to-weight ratio, versatility, ease of erection, high durability, and cost-effectiveness make steel joists and joist girders a common consideration for today’s roofing and flooring systems. However, the manufacturing of open web steel joists and joist girders is often left out of the discussion, leaving engineers and decision-makers wondering what kind of processes occur behind the curtains of the manufacturing plant. This article aims to shed light on the typical life-cycle stages of steel joists, from steel production to building decommissioning, leading the readers into the realm of open web steel joist and joist girder manufacturing and sustainability.

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Jun, 2022 By Laura Micheli, Ph.D., Bruce F. Brothersen, P.E. and Scott Russell, S.E., P.E. In Building Blocks Comments 0

Ground Snow Loads for ASCE 7-22

What Has Changed and Why?

The new ASCE 7-22, Minimum Design Loads for Buildings and Other Structures, ground snow load maps target uniform reliability rather than a uniform hazard (Bean et al., 2021). Previously, the ASCE 7 snow loads used a uniform-hazard 50-year mean recurrence interval (MRI) with a 1.6 load factor. These loads resulted in non-uniform reliability for structures across the country. The site-specific ground snow load determination is no longer tied to a uniform hazard (i.e., X-year recurrence interval) but to the safety or reliability levels stipulated in Chapter 1 of ASCE 7. The new strength level loads are used with a load factor of 1.0, as shown in Equation 1, and were selected to create uniform reliability across the country. These loads are mapped in the new ASCE 7-22 Chapter 7 in the online Hazard Tool and additionally reduced the number of case study regions by 90%.

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Feb, 2022 By Marc Maguire, Ph.D., Brennan Bean, Ph.D., James Robert Harris, P.E., Ph.D.,, Abbie Liel and Scott Russell, S.E., P.E. In Structural Design Comments 4

Snow Thermal Factors for Structural Renovations

The thermal factor, C_t, in the American Society of Civil Engineers’ Minimum Design Loads for Buildings and Other Structures, ASCE 7-16, is intended to account for expected changes in roof snow loads due to heat flow through the roof. As one might expect, for poorly insulated structures with large amounts of thermal energy available to melt roof snow, the C_t factor is low (C_t = 0.85 for certain greenhouses) while, for very well insulated structures, the C_t factor is high (C_t = 1.30 for freezer buildings). …

Jun, 2019 By Michael O’Rourke, Ph.D., P.E. and Scott Russell, S.E., P.E. In Structural Rehabilitation Comments 0

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