The distinguished career of Dr. Jon Peterka, Part II

It took about two years for CP/A, as the organization was then called, to get on its feet. Everything was built from scratch. From software and analysis procedures to data collection equipment and the wind tunnels themselves, all aspects of the new business were designed and built from the ground up. In those formative days of what would become CPP, Inc., Cermak and Peterka focused almost exclusively on wind loads on structures. But one kind of load in particular caught the attention of industry professionals.

Wind loads can be divided into straight line loads (forces) and twisting loads (moments). For convenience, engineers break each of these, in turn, into three individual forces or moments that represent the three dimensional world in which we live. When speaking about structures, for example, one might consider a force as having components that act in the east-west direction, in the north-south direction, and in the up-down direction. The real total force is the sum of all three acting together.

Building code procedures at the time offered no way to estimate one of the three components of twisting moments. Torsion, which is the tendency of a building to twist around a vertical axis under certain wind conditions, was not addressed in the code, and industry professionals needed a way to design for these conditions.

Cermak and Peterka were able to deliver torsional loads to clients as part of their wind tunnel testing services. The ability to quantify this load represented an important development in how buildings are designed for wind. Take a look at any modern skyscraper, and you’re unlikely to find simple square or rectangular cross-sections. Today’s tall buildings include structural features that disrupt the wind patterns that cause torsion and other load mechanisms.

In 1984, Ron Petersen joined Drs. Cermak and Peterka, and the company was renamed Cermak Peterka Petersen, or CPP. Dr. Petersen not only brought his detailed understanding of exhaust dispersion with him; he also brought many of the critical components of what is now Wind Tunnel 2 at CPP.

As the work of Cermak, Peterka, and Petersen defined the industry, Dr. Peterka continued serving as a professor at CSU. His passion for teaching had led to his being awarded the prestigious Honors Prof Award in 1977 and two teaching awards in the years since. But after more than two decades with CSU, the challenge of balancing dual full-time jobs led Jon to retire from academia to focus exclusively on the work of CPP.

Dr. Peterka also found himself increasingly involved with the American Society of Civil Engineers, or ASCE. One of ASCE’s many roles is the publication of Minimum Design Loads for Buildings and Other Structures (ASCE 7), which serves as the basis for building codes nationwide. And it is Dr. Peterka’s contributions to standards like ASCE 7 that will prove among his greatest legacies.