Soil-Structure-Interaction (SSI) is a broad and interesting topic. Because of its complexity and unpredictability, engineers often require the use of sophisticated analysis techniques, including specialized software. …
Base plate design” is a frequently misunderstood term, particularly when discussing attachments for post-installed anchoring applications. This article explains how the concept of base plate design, which is typically understood in the context of “column base plate design,” is not necessarily relevant to fixture attachment for post-installed anchoring applications. …
In May 2016, the American Institute of Steel Construction (AISC) published ANSI/AISC 358-16, Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications. It has been a significant influence on the research and development of products by government agencies, universities, and engineering research centers. Much of the research was done soon after the failure of steel moment frames during the 1994 Northridge Earthquake. …
The overall integrity and performance of a special moment frame, which is required in buildings assigned to Seismic Design Category (SDC) D, E, and F, is dependent on the behavior of the beam-column joints in the frames. …
Most designers who engineer reinforced masonry know that code provisions for lap splice lengths have been evolving over the past few code editions. A newer confinement-steel option is available that has the potential to significantly reduce the lap splice lengths, especially for larger diameter bars, through confinement of the structural reinforcement. …
In addition to supporting gravity loads, floor and roof systems in typical reinforced concrete buildings act as diaphragms which transfer the lateral forces to shear walls, frames, or other elements that make up the lateral force resisting system (LFRS). A three-dimensional analysis that considers the relative rigidities of the diaphragm and the elements of the LFRS provides the most accurate distribution of the forces in these components. A more straightforward analysis is possible when assumptions are made concerning the rigidity of a diaphragm. …
This article presents an overview of the design requirements for shallow reinforced concrete foundations (spread footings and mat foundations) supporting buildings assigned to Seismic Design Category (SDC) D, E, or F. Also included is a proposed design method that goes beyond requirements in current codes and standards. Although the following discussion focuses exclusively on spread footings supporting members of the seismic-force-resisting system (SFRS), it is also applicable to mat foundations. …
Today’s design, engineering, and construction professionals face a host of complex construction challenges. Industry initiatives focus on building a safer, more sustainable built environment. Owners seek maximum return on investments. Engineers pursue innovative technologies that maximize asset life and minimize life-cycle costs. …
Throughout the ages, humanity has been warned – do not build on weak foundations. Even the “Good Book” uses a parable of a home built on sand to emphasize the importance of a solid foundation in life.
However, the wise sages of the past did not live in today’s fast-paced world. As hard as most members of today’s society try to be good stewards of the land, some things get pushed to the wayside… literally. …
Recent developments in prescriptive fire resistance design resulted in the introduction and advancement of UL Design D982. A principal advantage of this UL design is that it provides the same fire protection thickness requirements for 2-hour assembly ratings regardless of whether the classification is restrained or unrestrained. …