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FEMA P-807 for Soft-Story Retrofits

Technical Considerations for Engineers

Prescriptive Performance-Based Design: An Innovative Approach to Retrofitting Soft/Weak-Story Buildings (STRUCTURE, September 2019) describes the approach contained in the Federal Emergency Management Agency (FEMA) P-807 guideline. P-807 is a method to retrofit a weak first story of wood buildings to mitigate side-sway pancake-type collapse, as depicted in the Figure. The hazard posed by such buildings was underscored by their damage in the 1989 Loma Prieta earthquake affecting the San Francisco Bay area, as well as in the 1994 Northridge earthquake in the Los Angeles region. Some cities in California have enacted ordinances mandating retrofit of soft-story buildings. …

Mar, 2020 By Bruce F. Maison P.E., S.E. In Structural Forum Comments 0

New Vision and Mission Guide NCSEA’s Direction in 2020 and Beyond

It is an honor to address you as the 2020 President of the National Council of Structural Engineers Associations (NCSEA). This is going to be an exhilarating year as we follow through with some significant changes. We are hosting the first-ever SEA Leadership Retreat in May, bringing together the leaders of the organization. We have changed our fiscal year to run from April 1^st to March 31^st. And, the Board of Directors is looking forward to further coordination and cooperation with our counterparts at the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE) and the Council of American Structural Engineers (CASE) of the American Council of Engineering Companies (ACEC). …

Feb, 2020 By Susan Jorgensen, P.E., SECB, F.SEI, F.ASCE In Editorial Comments 0

The 2020 Aluminum Design Manual

Spoiler Alert!

The next edition of the Aluminum Association’s Aluminum Design Manual (ADM) became available in January 2020 (Figure 1). Updated every five years, the Manual includes the Specification for Aluminum Structures which provides for allowable strength and load and resistance factor design of aluminum structures, members, and connections. Because compliance with this Specification is required by the International Building Code (IBC), changes to the Specification directly affect most building applications of aluminum in the United States. Furthermore, the Specification’s provisions are used by other code organizations, such as the American Welding Society (AWS) and the American Association of State Highway and Transportation Officials (AASHTO) in their standards for aluminum structures. This article reviews the significant changes to the Specification as compared to the 2015 edition. …

Feb, 2020 By J. Randolph Kissell, P.E. and Ronald D. Ziemian, Ph.D., P.E. In Structural Specifications Comments 0

Significant Structures

Suggested Language for Partial Practice Restrictions

The Structural Engineering Licensure Coalition (SELC) consists of representatives from the Council of American Structural Engineers (CASE) of the American Council of Engineering Companies (ACEC), the National Council of Structural Engineers Associations (NCSEA), the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE), and the Structural Engineering Certification Board (SECB). SELC has developed a document that provides a model definition for the term “significant structures,” which is used in structural engineering licensure legislation in several states and is being considered by several others to define partial practice restrictions. …

Feb, 2020 By Kristin Killgore, P.E., S.E., LEED AP In Structural Licensure Comments 0

Evaluation of Existing Timber Structures

Man has been building timber structures throughout Europe and Asia for over 4,000 years. In North America, timber structures have been built since the first Europeans arrived 400 years ago. Consequently, there are thousands of old timber structures still in service. …

Feb, 2020 By Jim DeStefano, P.E., AIA, F.SEI In Structural Rehabilitation Comments 0

Norwalk Bridge Disaster

This failure was not a structural failure but a failure of safe operational control of a wood and iron swing bridge built across the Norwalk River for the New York and New Haven Railroad. This line, as the name implies, was built to connect New York City with New Haven, Connecticut. The line was chartered in 1844, but construction did not start until 1847. The first train reached New Haven in January 1849. After leaving the New York and Harlem Extension at Williamsbridge, the line ran along the north shore of Long Island Sound and had to cross many streams and rivers draining from the mainland into the Sound. Some of these waterways were used for shipping, and the railroad had to provide for the boats using them. …

Feb, 2020 By Frank Griggs, Jr., Dist. M. ASCE, D. Eng., P.E., P.L.S. In Historic Structures Comments 0

Design-Build and the Structural Engineer

A Call for Leadership

Design-Build, though not new as a delivery method for building projects, appears to be on the rise. Traditionally known as the Master-Builder method, it is a means of building where one party holds responsibility for both the design and the construction. The Master-Builder method was the only method before the now ubiquitous design-bid-build project structure. The Romans for example, famous for their roads, aqueducts, and amphitheaters, did not design a project, bid it out to subcontractors, and then select the low bidder to build it, but rather designed and built structures in a collaborative, somewhat simultaneous fashion. …

Feb, 2020 By Ciro Cuono, P.E. In InSights Comments 5

Operational, Redundancy, and Ductility Factors for Bridge Structures

The structural design of buildings and bridges is currently based on the Load and Resistance Factor Design (LRFD) method. The main structural design philosophy is to maintain the factored resistance (the strength of the entire structure and all its elements) above the maximum demand from the worst possible combination of loads on the structure. The ratio of the strength to the demand represents the safety of the structure, where the nominal resistance is reduced by multiplying factors < 1.0, while the loads are increased by multiplying factors >1.0. These multipliers are the safety factors prescribed by the design codes and specifications for both building and bridge structures. For simplicity, all strength-reducing or load-demand-increasing factors are called safety factors in this article. …

Feb, 2020 By Roumen V. Mladjov, S.E., P.E. In Structural Forum Comments 0

The Future of Engineering

We are all busy taking care of our clients, delivering structural engineering expertise, and running our businesses; we probably do not take much time to sit back and contemplate the future of engineering and, more specifically, the impacts of future changes on structural engineering. Fortunately for all of us, there are organizations and groups of highly engaged professionals considering these questions and developing some interesting material and ideas. I am one of the professionals who believe the engineering profession is heading into a period of rapid change that will ultimately have an impact on all of us and society at large. …

Jan, 2020 By Stacy Bartoletti, S.E., Chair CASE Executive Committee In Editorial Comments 0

Cutting Prestressed Concrete Framing

Design and Construction Considerations

Existing owners often consider repositioning options for their buildings to serve an ever-evolving tenant market, accommodate new building uses, improve pedestrian circulation and accessibility, increase rentable tenant space, and more. Often, these buildings are served by an abutting above-grade parking structure, which can prevent horizontal expansion unless portions of the garage are removed to accommodate the expansion. …

Jan, 2020 By Michael F. Hughes, P.E., S.E. and Sal A. Capobianco, P.E. In Structural Practices Comments 0

Current Issue	Resource Guide

Review Category : Articles

Technical Considerations for Engineers

Spoiler Alert!

Suggested Language for Partial Practice Restrictions

A Call for Leadership

Design and Construction Considerations