December 1999: Monitoring of H-3 Viaducts
By: C. S. Papacostas
An impressive viaduct winds its way in North Halawa Valley to and from the portals of the H-3 tunnels. Worthy of special mention is the instrumentation installed on this viaduct to monitor long-term performance. Ian Robertson of the Department of Civil Engineering at the University of Hawaii was intimately involved in the task which he describes as follows:
In 1994, during construction of the H-3 Freeway, we, T.Y. Lin International and Construction Technologies Laboratory installed an extensive instrumentation system in the North Halawa Valley Viaduct. This structure is a 1-mile long box-girder viaduct with span lengths up to 360 ft. The viaduct was built by means of post-tensioned in-situ balanced cantilever construction.
The objective of the instrumentation program is to monitor the long-term behavior of the Viaduct, with particular attention to prestress losses and deflection. The instrumentation program was designed for an initial five-year monitoring period. Based on the excellent performance of the instrumentation, funding is being requested to extend the monitoring for an additional 5 years.
Four spans of the box-girder Viaduct were selected for instrumentation to provide an adequate representation of the Viaduct behavior. The instrumentation measures concrete strains, concrete temperatures, tendon forces, span shortening, span deflections, support rotations, and ambient temperature and humidity.
Field observations collected to date have been compared with analytical predictions obtained from the computer analysis programs used in the design of the structure. Computer prediction of short-term elastic events has proved extremely accurate, whereas long-term behavior is less predictable.
Researchers at UH are developing a procedure that will assist designers of future long-span bridges in generating realistic long-term predictions.
November 1999: Tunneling in Saprolite
By: C. S. Papacostas
Bill Hansmire, past president of ASCE-Hawaii and now Principal and VP at Jacobs Associates in San Francisco, was the project manager for the design and construction of the tunnels.
A couple of weeks ago, Bill sent me a copy of a paper he led in writing entitled "Design and Performance of Large Tunnel Constructed in Saprolite," a fascinating, in my view, account of the importance of sound engineering judgement in the analysis and design stages, as well as in the reanalysis and redesign activities that, more often than not, come up during the construction process.
Extreme care was taken to characterize the poor gound conditions at the Halawa side of the Koolaus due to the presence of saprolite, a highly to extremely weathered volcanic rock. To this end, an exploratory tunnel was built below the elevation of the main tunnels and special techniques (such as the introduction of foam and polymers in the drilling fluid) were applied to retrieve "undisturbed" samples for laboratory testing.
Advanced boundary element analyses predicted the stress distributions around the tunnel and showed that, with an appropriately designed ground support system, a "top-to-bottom" sequence of excavation drifts could work in this case despite the prevailing poor ground conditions.
The initial analysis stage used a range of strength parameters that were based on the test regime results and, of course, on engineering judgement.
During construction in the saprolitic region, instrumentation was installed for in situ testing. Convergence (that is, the shortening of the distance between selected points inside the tunnel) was also continuously monitored.
The tunnel which now carries Honolulu outbound traffic was started first but was completed last: Tunneling operations had to be stopped and remedial treatments had to be devised when the top heading advanced a little more than 200 feet from the portal. Convergence was reaching 0.9% of the tunnel's diameter and this could stress the saprolite beyond its elastic range, with possibly disastrous results.
The project's design review panel was convened to resolve conflicting interpretations of the situation and boundary element modeling was again applied, this time using revised parameters obtained from the in situ testing. A revised ground support design and construction sequence that ensured the safe completion of the project was the result.
In my view, this case study also illustrates that qualifications-based (rather than low-bid) procurement ensures that the necessary expertise is present to deal with the problems that inevitably arise during the construction of complex projects.
October 1999: H-3 Highway Tunnels
By: C. S. Papacostas
During the TRB meeting in Washington, D.C. last January, I had a pleasant lunch with William (Bill) Hansmire, past president of the Hawaii section of ASCE.
Bill was the project manager for the design and construction of the H-3 tunnels. He is now Principal and VP at Jacobs Associates in San Francisco, specializing in design and construction services for large underground projects throughout the world.
During lunch, Bill mentioned that he was working on a paper that documented the history of the H-3 tunnels and I jumped at the opportunity of helping to share his first-hand knowledge of the project with the engineering community in Hawaii. He promised to send me a short write-up.
True to his word, while on a job in Singapore, he found the time to e-mail a summary of a paper he co-authored and published with three colleagues, including Hawaii section member Clayton Mimura, President of Geolabs Hawaii.
Bill's summary concludes that, "In retrospect, the Trans-Koolau tunnel benefited from the long delay from its inception in the 1960's to its completion in the 1990's. During this delay ..., the experience and lessons learned on other tunnels, from technology and materials improvements, to changes in design practices, were usefully employed on this project."
The summary also points out that some of the notable engineers involved in major technological breakthroughs were also part of the Trans-Koolau team.
Memory of a catastrophic collapse during the construction of the Wilson Tunnel in 1954 (March 1996 article ) was a real public concern that had to be overcome by the H-3 engineers. Ralph B. Peck, who had devised a hand-mining technique to complete the Wilson Tunnel project in soft ground and had later written a definitive account of the experience, became a key consultant for the design of the Trans-Koolau Tunnel.
Another consultant, A. A. Mathews, brought to Oahu his direct knowledge of "risk-sharing practices of Disputes Review Boards and Escrow Bid Documents," pioneered during the 1970's on the construction of Colorado's Eisenhower (originally Straight Creek) Tunnel.
The 1984 documentation by Ed Cording of advances made on the Washington, D. C. Metro also enhanced the H-3 project. These included "ground reinforcement by rock bolts, dowels, and shotcrete [that] replaced ground support by structural steel" and the large-scale implementation of "risk-sharing and disputes resolution contracting practices."
September 1999: Code of Ethics
By: C. S. Papacostas
According to the official history of ASCE, the Society's Board of Direction initially resisted the adoption of a written Code of Ethics, believing that ethics was a matter of personal responsibility on the part of the engineer. In 1877 for example, the Board resolved that it is inexpedient for the Society to instruct its members as to their duties in private professional matters. This position, however, changed in 1914 when a special committee was given the task of developing a formal Code which was approved by the membership and adopted on September 2, 1914. The original Code emphasized the relationships between engineers with their clients and with other engineers, rather than their responsibilities to the public.
In 1961, the Board adopted the Guidelines to Practice and, in May 1964, it endorsed its Fundamental Principles. These were amended in April 1975.
Before 1971, the Code considered unethical to invite or submit priced proposals under conditions that constitute price competition for professional services. This provision was challenged by the U.S. Department of Justice as constituting a violation of the Sherman Antitrust Act.
In October 1971, ASCE voluntarily removed the provision from its Code of Ethics. The American Institute of Architects took the same action with a similar provision in its Standards of Ethical Practice. The National Society of Professional Engineers, however, resisted the change and subsequently lost a U.S. Supreme Court case on the matter.
The most recent revision of the ASCE Code occurred on November 10, 1996. This amendment addressed the issue of sustainable development. According to the Board, Sustainable Development is the challenge of meeting human needs for natural resources, industrial products, energy, food, transportation, shelter, and effective waste management while conserving and protecting environmental quality and the natural resource base essential for future development.
August 1999: Long-term Pavement Preservation
By: C. S. Papacostas
Last month I talked about the background and design philosophy that motivated a multi-year (and continuing) effort to develop Superior Performing Asphalt Pavements or "superpave."
A 1984 special report by the Transportation Research Board of the National Research Council entitled "America's Highways: Accelerating the Search for Innovation" provided a major thrust to the program. This report advocated the following broad objective:
Increase pavement life by the investigation of the long-term performance of various designs of pavement structures and rehabilitated pavement structures, using different materials and under different loads, environments, subgrade soils, and maintenance practices.
The new design approach on which superpave was based has received considerable exposure. Other aspects of the program have not.
For example, the Long Term Pavement Performance Information Management System (LTPP IMS) is not as well known.
LTPP IMS is a data base intended to support the overall program. Statistical sampling techniques were employed to identify approximately 1,100 roadway test setions throughout the U. S. and Canada to be monitored over a 20-year period. The sample was designed in such a way as to capture the effects of pavement structure, materials, traffic, subgrade, environmental conditions and their interactions.
The selected test sections fall into two categories referred to as General Pavement Studies (GPS) sections and Specific Pavement Studies (SPS) sections. The former consisted of existing pavements as originally constructed or after the first overlay. The latter included the construction of new sections in a manner that would allow experiments not possible with GPS sections. Four GPS sections are located in Hawaii.
The LTPP IMS data base development and maintenance procedures pay special attention to consistency and quality control. The current data base, along with special-purpose data extraction software, is available on CD-ROM.
July 1999: Superpave
By: C. S. Papacostas
Not long ago, the Hawaii Department of Transportation placed its first pavement section designed in accordance with the level 1 "superpave" mix design. The test section is being closely monitored and evaluated against traditional mix designs as part of a national program.
Nearly one-third of the $150-million funding for the Strategic Highway Research Program (SHRP, 1987-1993) was spent toward the development of what the Office of Technology Applications of the Federal Highway Administration (FHWA) calls the Superior Performing Asphalt Pavements, "superpave" for short. SHRP itself was authorized by the Surface Transportation and Uniform Relocation Act of 1987.
Thereafter, continued development of Superpave has been supported through partnerships between FHWA, AASHTO, the Asphalt Institute, six "lead" states and selected universities. As part of the initial program, a test facility, Westrack, was constructed in Nevada. It consists of an oval track containing 26 sections intended to test combinations of 21 different variables affecting pavement performance. By 1996, the track saw an equivalent of one million ESALs.
Superpave mix design comes in three levels and special testing equipment have been devised: the Superpave Gyratory Compactor that simulates how the pavement would perform under expected traffic loads, the Superpave Shear Tester and the Indirect Tensile Creep Tester. The first (which can be replaced by other gyratory compactors meeting certain criteria) is used by all three design levels, whereas the other two are required by the increasingly sophisticated levels 2 and 3.
The basic idea behind superpave is to effect a paradigm shift from using traditional empirical properties that are CORRELATED with pavement performance to performance-based engineering properties that can be used to PREDICT pavement performance.
Level 1 design is strictly volumetric and represents a natural evolution from the work of Richardson (1905), Marshall (1940s) and McLeod (1950s) that established the parameters used by the Marshall design method. Superpave, however, introduced binder specifications (known as Performance Grades, PG) that are sensitive to climatic conditions (high and low temperatures) adjusted by traffic loading (ESALs and traffic flow characteristics).
Five mix types are defined based on the nominal maximum aggregate size with broad gradation control points and a "restricted" zone. Aggregate specifications, which also include coarse and fine aggregate angularity criteria, have been established by concensus rather than research. The "restricted" zone represents a portion of fines that the experts thought to result in "tender mixes" that encourage rutting. Subsequent field experience has challenged (but has not resolved) this assumption.
Levels 2 and 3 involve more advanced testing that produce inputs to special software aimed at predicting pavement performance. Unfortunately, recently discovered flaws in both the testing procedures and the software have delayed release of these specifications.
June 1999: No Article
May 1999: Regional Transportation Plan
By: C. S. Papacostas
In my November 1998 article I described the confluence of historical events that led to the federal requirement to designate a Metropolitan Planning Organization for every major urban area in the country.
Ours is called the Oahu Metropolitan Planning Organization (OMPO). It was created back in 1975 and, as the name implies, its area of influence covers the island of Oahu in its entirety.
But what is it that these MPOs are expected to do?
In essence, they are required to coordinate multimodal transportation planning within their area of influence and to involve all stakeholders in the process. They are also required to produce long-range plans and short-range implementation programs that are consistent with them.
Beginning with the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991, MPO plans must also be "financially contrained." The Transportation Efficiency Act for the 21st Century (TEA-21) retained this requirement.
The long-range plan for Oahu is known as the Oahu Regional Transportation Plan (ORTP). It is required to have a time horizon of at least 20 years and to be updated every five or so years.
The first such plan, entitled the Oahu Transportation Study (OTS), was issued in 1967. The latest ORTP was published in November 1995 and carries a target year of 2020.
As the year 2000 approaches, OMPO is preparing to embark on a plan update.
It behooves ASCE and other groups concerned with transportation to participate in this most important process.
April 1999: The Father of the Stop Sign
By: C. S. Papacostas
According to his own writings, William Phelps Eno experienced his first traffic jam at the age of 9 on Broadway. His family's carriage was stuck in the jam for half an hour and nobody knew what to do about it. That incident happened in 1867.
According to the Eno Transportation Foundation, which he founded and endowed in 1921, at age 41 he issued a treatise on the "necessity for rational management and observance of the rules of the road and their enforcement." His "Rules of the Road" became law in New York City in 1909. His ideas were accepted in major European cities and he was awarded France's Legion of Honor for a traffic plan the French call "Le Systeme Eno."
Among his proposals in this country were traffic circles, pedestrian crosswalks, right-side driving, pavement markings, traffic signs, drivers' licences, vehicle registration and citations for traffic violations.
The "father of the stop sign" left his family's real estate business in 1899 and made traffic safety and regulation his main avocation.
The Eno Foundation's headquarters remained in Wesport, Connecticut until 1992 and is now located in Landsdowne, Virginia. The Foundation's seal, which he designed, bears the logo "Ex Chao Ordo" which means "Order out of Chaos." It also carries three dates: 1887 when he became convinced that traffic regulation was necessary, 1899 when he decided to devote himself to the crusade of transportation reform, and 1921 when he established the foundation.
In addition to roadway traffic safety and control, he produced the concept for a subway in New York City, supported maritime and railroad activities and, in the 1920s, began researching the future impacts of aviation. William Phelps Eno, one of the founders of the Institution of Transportation Engineers, died in 1945.
March 1999: First Civil Engineering Textbook
By: C. S. Papacostas
1838: Mahan publishes his text, Civil Engineering, West Point, NY.
This entry in the 1998 edition of ASCE's History and Heritage of Civil Engineering intrigued me. We are all familiar with engineering texts, particularly those we used in school, but was this the first one?
And who was Mahan?
In search of an answer, I connected to my favorite search engine on the internet. I entered the keywords Mahan and civil engineering and checked the return results. The first one started out: "Rear Admiral Alfred Thayer Mahan was born ... at West Point, New York, where his father Dennis Hart Mahan, was a distinguished professor of civil and military engineering at the U.S. Military Academy."
Naturally, I revised my search to look for Dennis Hart Mahan. A page at the web site of the Arlington Cemetery popped up:
Dennis Hart Mahan, Commodore, United States Navy. Born at West Point, New York ..., the son of Professor Dennis Hart Mahan ...
The next web site on the list was that of the City of Alexandria, Virginia. Fort Ward, the best preserved of those built during the Civil War to protect Washington, D.C., was listed as one of the important visitor attractions in the area. In the accompanying description, I read:
"Dennis Hart Mahan ... was primarily, if not solely, responsible for the theories of defensive warfare used by the Union and Confederacy ..."
Two books by Mahan on Field Fortifications were cited but not the elusive civil engineering text.
On to the next web site (www.virtualtexan.com) and a short history of Fort Worth, a fort that became a town. Here I found an explanation of the similarity of most frontier posts. It was because the officers who built them came from a common background. Every graduate of West Point after 1830 had studied civil and military engineering under the brilliant Dennis Hart Mahan.
The web site of Jeffrey Thomas Fine and Rare Books in San Francisco offered for sale a copy of Mahan's 1836 Treatise on Field Fortifications (268 pp. Twelve folding plans) and a short biography of the author: "Dennis Hart Mahan (1802-1871) abandoned medical school in 1820 to attend West Point where he graduated at the head of his class in 1824. He earned a commission as 2nd Lieutenant in the Corps of Engineers and taught mathematics and engineering at the Academy. The War Department sent him to study under Napoleon's officers at the School of Engineering and Artillery at Metz, France. He returned to West Point in 1830 and taught until his death in 1871."
Finally, at the web site of the Department of American Studies at the University of Virginia, a paper by Edwin Layton informed me that Mahan also produced the first American textbook based on French engineering practice. An Elementary Course of Civil Engineering sold 15,000 copies and fundamendally influenced the teaching and practice of engineering in this country.
February 1999: Notable Civil Engineers
By: C. S. Papacostas
The recently issued 1998 edition of the "History and Heritage of Civil Engineering" contains a section entitled Special ASCE Recognition of five notable civil engineers. They are:
January 1999: Early U.S. Bridges
By: C. S. Papacostas
Last month I mentioned the publication of the 1998 edition of ASCE's "History and Heritage of Civil Engineering."
This month we present a short list of "firsts" in American bridge building from that publication:
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