Home ⁄ 2022 (page 29)

Historic Alameda High School Retrofit

Part 1: Too Valuable to Demolish, Too Expensive to Retrofit

In 2012, the Alameda Unified School District in Alameda, California, made the difficult decision to fence off and vacate all three historic classroom buildings on the Historic Alameda High School (HAHS) campus due to seismic safety deficiencies. These buildings and the attached auditorium, lobby, gym, and locker room buildings had stood since 1924. However, the classroom buildings lacked approval under California’s Field & Garrison Acts, putting the school district at legal risk (and any building occupants at life safety risk). The long process to rehabilitate and restore these nearly century-old buildings had entered its final chapter.

…

Jan, 2022 By Nik Blanchette, P.E., Steve Heyne, S.E. and Chris Warner, S.E. In Feature Comments 0

Wanted: Public Service

By the time you are reading this, the 2021 election season is behind us. Although the recent elections did not have national office implications, offices for elected officials were likely held where the reader lives. Did you participate in any way? Did you take the opportunity to vote? Have you ever considered running for elected office?

…

Jan, 2022 By Brent White, P.E., S.E. In Editorial Comments 0

Shear Strength Deficiencies in Concrete Columns

Part 1

Concrete buildings with vulnerable columns are some of the most dangerous structures when earthquakes occur. Since the 1970s, building codes have addressed the detailing of columns that are part of moment frames in high-seismic regions. Research for the Portland Cement Association [Blume et al., 1961] and subsequent studies in New Zealand established the need for close spacing of ties and a capacity design of frame members for shear strength sufficient to cause flexural yielding rather than undesirable shear failure.

…

Jan, 2022 By Lawrence Burkett, Joe Maffei, S.E., Ph.D., Abby Enscoe, P.E., Marc Steyer, S.E., Mike Wesson, S.E., Ph.D. and Aniket Borwankar In Structural Performance Comments 0

2021 IBC Significant Structural Changes

Part 3: Special Inspections (Chapter 17)

This five-part series (Part 1, STRUCTURE, November 2021, Part 2, December 2021) includes discussion of significant structural changes to the 2021 International Building Code (IBC) by the International Code Council (ICC). This installment includes an overview of changes to Chapter 17 on special inspections and testing. Only a portion of the total number of code changes to this chapter are discussed in this article. More information on the code changes discussed here can be found in the 2021 Significant Changes to the International Building Code, available from ICC (Figure 1).

…

Jan, 2022 By Sandra Hyde, P.E. and John “Buddy” Showalter, P.E. In Codes and Standards Comments 0

FAQs on ASCE Standards

What You Always Wanted to Ask

Welcome to this new quarterly column for STRUCTURE magazine. These articles will address some of the questions received (along with responses) about structural standards developed by the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE), such as ASCE 7 and ASCE 41. Questions received from engineers, building officials, and other design professionals are often considered for the development of future editions. Following are some questions received by SEI as well as responses to clarify the provisions.

…

Jan, 2022 By Laura Champion, P.E., F.SEI, F.ASCE and Jennifer Goupil, P.E. In Just the FAQs Comments 0

Snow and Rain Loads in ASCE 7-22

Part 1

The American Society of Civil Engineer’s ASCE 7-22 load standard, Minimum Design Loads for Buildings and Other Structures, is now available. Substantive changes have been made to the snow and rain provisions within the standard. In particular, the ground snow loads have been revised to reflect more recent snow load data and reliability-targeted values. In addition, the method for estimating drifts has been revised to include a wind parameter, and the procedure for determining design rain loads has been revised to explicitly consider a ponding head. Some of the more substantive changes are discussed, along with the reasons for these changes. This article is Part 1 of a two-part series and reviews the new ground snow loads and a new winter wind parameter. Part 2 will include the other more substantive changes to the snow load provisions and the new rain load provisions.

…

Jan, 2022 By Michael O’Rourke, Ph.D., P.E. and John F. Duntemann, P.E., S.E. In Structural Loads Comments 0

The Long Road

Advancing First-Generation Performance-Based Seismic Design for Steel Buildings

Part 3: Future Efforts for All Structure Types

Capabilities to conduct a performance-based seismic design (PBSD) of retrofitted existing buildings and new buildings have advanced exponentially over the past 25 years. This progress has augmented our knowledge of building behavior given an earthquake intensity. Still, we must be cautious of considering a PBSD as an exact answer; instead, a PBSD gives us information to support decision-making. There is still much work needed to support PBSD capabilities, and this depends on the type of assessment being conducted. At the same time, a vision for the not-so-distant future must also be established.

…

Jan, 2022 By Matthew S. Speicher, Ph.D. and John Harris, Ph.D. In Structural Design Comments 1

Two-Stage Analysis Loophole

Engineering projects and building code provisions can often seem like Rorschach tests where two people looking at the same thing can draw sharply different conclusions. This article reviews the two-stage analysis procedure in ASCE 7-16, Minimum Design Loads for Buildings and Other Structures, to consider if the provisions are an innocent inkblot or possibly may be interpreted differently by some.

…

Jan, 2022 By Steven Shepherd, S.E. and James McDonald, S.E. In Structural Analysis Comments 0

The Hidden Cost of Copy and Paste

Part 2

In the first installment of this discussion (STRUCTURE, December 2021), I looked at 3 examples of bad habits in contract documents that can cause problems later for fabricators. This month, I offer an additional four examples.

…

Jan, 2022 By Jason McCool, P.E. In Engineer's Notebook Comments 0

Niagara’s Upper Falls Bridge Failure

Leffert Lefferts Buck (STRUCTURE, December 2010) had long experiences with bridges across the Niagara River. First, he replaced wires and added anchorages to Roebling’s 1855 suspension bridge. He followed this with replacing the wooden trussing with iron and, still later, he replaced the stone towers with iron, all of these without stopping traffic for any extended period. These modifications took place between 1877 and 1886. With his associate R. S. Buck, he replaced Edward W. Serrell’s Lewiston/Queenston Suspension Bridge in 1889. He widened and strengthened Samuel Keefer’s 1868 Honeymoon Suspension Bridge in 1888. Unfortunately, the deck collapsed in a fierce windstorm in 1889, shortly after it opened. He rebuilt it within two months. In 1895, the owners wanted to widen the bridge and have it support trolley traffic. Buck was chosen to design and build an arch bridge under and around his bridge in 1897. He chose a braced arch, open-spandrel span of 840 feet that made it the longest arch span in the world when it opened on June 20, 1898.

…

Jan, 2022 By Frank Griggs, Jr., Dist. M. ASCE, D. Eng., P.E., P.L.S. In Historic Structures Comments 0

Current Issue	Resource Guide