MANAGEMENT
By Michael Walsh
Failing to Plan or Planning to Succeed? Dealing with the physical realities of temporary or partially completed structures
Maintain balance, dynamic stability, and structural integrity of individual building elements.
B
enjamin Franklin famously coined the phrase, “If you fail to plan, you are planning to fail,” which is an adage that is highly applicable in construction, with compressed schedules and strained supply chains. Practical solutions to complex problems demand speed and collaboration, particularly for those like steel erectors, who are at the “tip of the spear” on a project. Timely planning is critical, and erection engineering is critical to planning. Project design teams work in a virtual world where individual building elements are treated and function as completed systems. Steel erectors, however, deal with the physical realities that accompany temporary and partially completed structures, until that completed design stage is achieved. Regardless of the stage of construction, erectors are required to maintain structural stability and integrity, while being resistant to temporary and transient loads that may exceed those of the final design. Permanently Michael Walsh is President of Dearborn Engineers & Constructors, Inc., Bridgeview, Illinois, a leading consultancy specializing in heavy lift, heavy transport and construction-erection engineering on a national basis. Contact him at MWalsh@DearbornCos.com.
installed elements need protection from overstress and potential damage. Beyond simply making sure that the structure stands-up, the construction also needs to move forward safely, efficiently and cost effectively. Key in making all of this happen is the early involvement of an experienced erection engineer (EE) in the planning process.
Codes, Standards, Design Intent At the start, a practiced EE will be able to assist you in utilizing the correct code or industry standard, which can dramatically impact the safe, successful, and timely completion of your project. Nuanced differences in design values and safety factors among AISC 303, ASCE 37, SJI, and/or PCI standards can have significant effects on sequencing and costs of bracing, shoring, and temporary supports. Personal experience has shown ASCE 37 to be a bit more reflective of actual encountered loads, which can offer some benefits in terms of sizing and positioning of bracing and supports, but each project must be evaluated on a case-by-case basis. It is very important to remember that codes and standards provide the minimum criteria to be met and often do not rise to the level of what’s deemed
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“good” (not “best,” but good) engineering or industry practice. Development of a clear understanding of the “Engineer of Record’s” (EOR’s) intended performance of the completed structure is critical, and your EE will provide insights to help avoid the potential for overload conditions. All loads – live, dead, construction (including material staging, tools, and equipment), shoring and bracing, safety related, and even surcharges and earth pressure loads – require consideration. Understanding the completed structure’s performance will identify where temporary erection loads can be dragged and offer you real guidance in where to physically start the erection process.
Sequencing the Work Steel erection is, by its nature, an iterative process. Sequencing of the work requires maintaining a balance between structural stability and the ability to physically access building elements and efficiently perform the work. As an example, the choice between first starting a building with its exterior precast concrete shear walls versus starting with its structural steel frame can have a profound impact on the sequencing and temporary supports for both erection processes.
