When the author entered the industry 41 years ago, there were no desktop computers. Everything was done by hand calculation, punch cards, and hand drafting. There were “job checkers,” a person in the architect’s office who continuously checked the project team’s drawings for coordination, completeness, and constructability. Projects followed a set schedule. …
Although the ASTM A913 specification has been around for over 20 years, there has recently been a renewed interest in using ASTM A913 Quenched and Self-Tempered Structural Steel Shapes. Weight and cost savings are obtained by using the higher strengths of A913 versus conventional A992. For building structures, the most significant advantage of this specification is for column and truss sections where the designer can realize a 10 to 20% weight saving by using the higher strength available in A913 Grade 65 as compared to the standard 50 ksi yield strength of A992. …
Despite the politicization of the climate change conversation, there is overwhelming scientific evidence that our climate is altering in a way that is placing added stress on communities, infrastructure, and the general health and well-being of society. …
As I write this editorial, many communities and cities in the United States are just starting to “re-open” following the Coronavirus pandemic and shelter-in-place orders. My firm, like most, transitioned into a full work-from-home situation in March with only minor issues and challenges. Our business and employees have adapted remarkably well. We are conducting meetings virtually through video calls, developing and reviewing construction documents by sharing data and models, accessing information through the cloud or virtually from our servers, and participating in new project interviews remotely. Employees are doing their best to remain engaged and connected with one another. …
Recent media coverage has highlighted the devastation associated with tornado outbreaks in many urban and suburban areas. Rapid population growth and urban sprawl in many cities within the central United States have increased the number of structures located within the potential path of these dangerous storms. Tornadoes generate high winds and extreme loads that are significantly higher than typical building design loads. …
Canopies can either be free-standing structures or can be attached as a structural component to a main building structure. They can be situated at an entrance of the building, acting as awnings, or they can be located anywhere along the face of the building up to the roof level. Canopies are not only used for protection of the entrance from dust and rain but also to increase the aesthetic appeal of the overall structure by either becoming integrated into the building or by highlighting it. Hence, there is a need to economically design the size and shape of the canopy and its connections. …
Tall building designers are increasingly facing challenges related to wind and earthquake-induced vibrations, especially as buildings are built taller and more slender. Frequent windstorms can cause lateral accelerations, which can result in occupant discomfort. Rarer, more severe windstorms and service level earthquakes (SLE) produce large loads in the structure that have to be resisted elastically by the structural members. A primary cause of these vibrations is the low levels of inherent damping (the ability of structures to absorb vibrational energy and slow down dynamic vibrations) in taller structures. Furthermore, severe earthquakes can cause distributed damage throughout the entire structure in conventionally designed buildings, putting in question their post-earthquake safety and use. …
The recent publication of the ASCE/SEI Prestandard for Performance-Based Wind Design (Prestandard), and the upcoming publication of a Manual of Practice on Design and Performance of Tall Buildings for Wind prepared by an ASCE/SEI Task Committee, make this an apt time to provide an overview of the intent of these documents, the present state-of-the-art in Performance-Based Wind Design (PBWD), and current efforts to update knowledge. …
When a major tornado happens, it is all over the news. And, every year, the average person may recall hearing about a dozen or so tornado events, if that. So it might be startling to know that, on average, the number of tornadoes that touch down each year in the United States, according to www.ustornadoes.com, is more than 1,200. …
The ASCE 7-16, Minimum Design Loads for Buildings and Other Structures, has been published in accordance with the International Building Code (IBC 2018), incorporating updates regarding wind load calculations from ASCE 7-10. This article relates to wind uplift on flat and gable roofs of major logistic centers with slopes ≤ 7 degrees and buildings ≤60 feet in height. The article focuses on the wind uplift loads on the roof elements of joists and girders. For joist wind uplift loads, the method of Components and Cladding in Chapter 30 of ASCE 7 is adopted. For girders, considering the effective wind area is larger than 700 square feet for typical major logistic centers, the Main Wind Force Resisting System (MWFRS) method in Chapter 27 is adopted. …