By Dave Bourgault, VP Planning and Development, (memo to Stresscon's staff based on interview with Don after his “Titan Award”)

In celebration of its 50th anniversary, the Precast / Prestressed Concrete Institute honored 50 people as “Titans” who, over the past 50 years, made “outstanding contributions to the industry”. The award cited these individuals “for prominence in industry innovations and change; for positive leadership in industry-altering development and expansion; and for advancing the growth of the North American Precast and Prestressed Concrete industry”.

Of the 50 so honored, 20 are deceased, leaving 30 living recipients, many of whom reached prominence in the 50s and 60s during the early stages of the development of the industry. Most of the Titans have been prominent outstanding professional engineers and university researchers. Don Logan is among a few who are founders and CEOs of prestressed concrete producer companies.

Don was present at the birth of this industry while a student at Drexel Institute of Technology in Philadelphia , where he witnessed the construction of the nation's first major prestressed concrete project, the Walnut Lane Bridge . This was followed by 3+ years service in the US Navy Civil Engineer Corps, where he was involved in the Navy's pioneering use of precast concrete construction for naval bases near San Diego , California , and later in Virginia .

Upon his release from the Navy in 1956, Don joined with his friend and Drexel classmate, Joe Schneider, co-founding and, co-managing, for 7 years, one of the first prestressed concrete companies in the USA , Camco Concrete, a division of a concrete block company in New Jersey . During this period, Don conducted full-scale load tests on a variety of products and loading conditions, to better understand their structural behavior. He was also able to fit in night classes at the University of Pennsylvania , earning a Master's Degree in Structural Engineering in 1963.

To expand Camco's product line, Don experimented with a new long line hollow-core slab process. After extensive “proof tests”, he developed it into an operating process and it became a successful product in their market area.

Don's structural tests on this product revealed several newly discovered phenomena:

• The transfer of prestress from the bottom flange through the thin webs of hollow-core slabs caused premature horizontal shear failure, requiring modifications to shear design equations.

•  The post-cracking behavior severely changed the deflection characteristics of hollow- core slabs and led to equations that he proposed to predict such behavior. (Pre-dating current bi-linear deflection equations.)

•  Companion post-cracking load/deflection tests of double tees, led to further modifications to his equations.

•  Don also conducted a full-scale test of a compact prestressed L-beam and was able to demonstrate that torsional twisting could not be induced by application of vertical loading. Instead, the failure mode was lateral bending about the weak principal axis of the L-shaped beam.

•  Don “proved” in a load test, that any prestressed double tee adequately designed for flexure could not fail in shear, and required no shear steel. (He now says, “Can't win them all!”)

Don's structural research and tests, much of it controversial, led to guest lectures at local and national engineering group seminars, and an invitation to lecture at Dartmouth College . In 1963, Norm Scott, of PCI, asked Don to join the newly formed Allowable Stresses Committee to examine partial prestressing and the consequences of Don's post-cracking behavior concept.

One of the highlights of his early career was his service in the mid-60s with Concrete Technology Corporation, Tacoma , Washington , the acknowledged international leader in this industry at that time. There, Don worked closely with Bob Mast on the continuation of Don's partial prestressing concepts and their application to the design of deck products, separating service design from ultimate design, in order to reduce undesirable camber of deck products.

Bob introduced Don to the shear-friction concept, and shear wall design. After Don's trip to Anchorage, Alaska, where he studied damage to buildings from the world's largest recorded earthquake (9+ Richter Magnitude), Don proposed several concepts attempting to explain the superior performance of shearwall structures in this massive seismic event. Although those concepts were never validated, they triggered Don's 40-year quest to find the answer.

Recognizing his broad understanding of the technical and the business sides of the precast concrete industry, the owners of Concrete Tech, Art and Tom Anderson, encouraged Don (and assisted him in obtaining a $46,000 loan from the Small Business Administration) to start Stresscon Corporation in Colorado Springs in late 1967.

In planning this new company, Don conceived, and later implemented, a unique multi-entrepreneurial organizational structure designed to generate negotiated sales, and to develop the total precast structure market.

Eliminating traditional sales and engineering departments, Don visualized a horizontal organizational structure consisting of structural engineers/project managers, each promoting and selling their projects, and then, together with small teams of technically trained project coordinators, managing and engineering their projects through completion.

Plant crews would be composed of small teams performing all functions on each facility, from start to finish, creating their own structural concrete products, every day.

Starting with 13 people in a 3-acre plant, Stresscon, through the efforts of its outstanding people at the operational, technical and administrative levels, gradually grew, acquiring an architectural concrete plant and a hollow-core plant in Colorado , opening plants in Texas and Maryland , and starting a wall panel plant north of Denver . By the year 2000, Stresscon employed over 350 people, with sales exceeding $65 million.

During the 70s and 80s, Don continued with structural testing at Stresscon; worked with Jerry Jacques on structural tests at Stanley Structures; with Jerry and Alan Mattock on a double tee dap testing program at the University of Washington; with Roger Becker on hollow-core tests at the University of Wisconsin through the mid-80s; and, on strand bond tests at the University of Colorado, with Mark Brooks (co-author of their PCI Journal article in 1988).

His more recent research and testing of the bond of steel strand to concrete uncovered the cause and detection of previously unexplained erratic strand bond behavior, and led to his winning the Martin Korn Award, PCI's highest award, and the prestigious T.Y. Lin Award, the American Society of Civil Engineer's highest technical award in the field of prestressed concrete.

At the Titan Award ceremony in Atlanta , Georgia on 19 October 2004, Don was cited by PCI for his “career-long obsession with practical structural research and full scale testing”, trading ideas with the highest level of outstanding practical researchers of the industry, leading to engineering breakthroughs, and co-founding the Colorado Prestressers Association, our technically oriented industry group.

In 1994, Don was “lucky” enough to experience the Northridge earthquake in California . His immediate examination of the comparative behavior of stiff vs. flexible structures appeared to unlock the answer to the shearwall superiority question.

In 1995, Don was invited to be a member of a 3-man team, to examine the behavior of structures in the Kobe , Japan earthquake, joining SK Ghosh and Mark Kluver, both recognized seismic design experts. While SK and Mark studied conventional seismic behavior concepts, Don was able to clearly establish the validity of his emerging soil-structure interaction concept that provided the rationale for the superior performance of shearwall structures in severe seismic events.

Subsequently, in September 1999, Don led a PCI team (including SK Ghosh, Ned Cleland, and Phil Iverson) on a tour to examine the behavior of a variety of structures under different soil conditions during the massive August 1999 earthquake in Turkey . All team members agreed with the validity of his soil-structure interaction concept.

Currently developing a research program to transform this concept into a seismic design procedure, continuing to perform on-going testing of strand bond, structural testing of self- consolidating concrete, and just getting underway with L-spandrel tests to “prove”, again, that torsional distress can not be induced in precast concrete L-beams, Don's “obsession” continues.

Let us congratulate Don for being awarded this industry's highest honor, and don't believe him when he says, “It was no big deal”!