Producing Armourstone Within Aggregate Quarries
This paper discusses a series of full-scale trial blasts which was conducted in an aggregate producing quarry with the objective of improving yields of armourstone. The quantitative research...
Recent Experience With Armor Stone Cracking in the Buffalo District
Accelerated deterioration of large armor stone on the Cleveland East Breakwater, Cleveland, Ohio has resulted in the need for more intensive monitoring of the entire armor stone production...
Learning to Love NDT
Sometimes overblown claims and the practical limitations of early nondestructive tests for concrete have left many civil engineers leery of NDT methods. While some are aware that NDT has...
Rail Revival
Rail transit appears to be on the upswing. More than 30 cities are building, extending or seriously considering new rail-transit systems, according to a recent report from the Regional...
Staffing Up for a Major Program
A nine-member construction management section must pilot a $335 million, multi-project capital improvement program over the next five years. Should construction management duties automatically...
Making Teamwork Work
From consulting firms to steel workers, most work groups would benefit enormously from developing better teamwork, but making it happen isn't easy. Excerpts from
Frequency Spectrum Analysis of Ultrasonic Testing Signal in Concrete
Description is given on high-speed sample apparatus connected with the CTS-25 low frequency ultrasonoscope and computer, the time domain of ultrasonic testing signal is transformed to...
VOCs: The New Effluent
The Clean Air Act of 1990, in addition to many state and local regulations, has officials of publicly-owned treatment works (POTWs) shifting their focus, and funds, to air toxic emissions...
A New Era In Transportation
Its passage into law was about as smooth as a rush-hour traffic jam, but the surprising thing about the new Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) is that it...
Project Management: Keys to Success
Successful construction projects can be traced to several key factors observed by the owner, the AE and the contractor. They include: 1) Goals and commitment of the managing partners agreed...
Actively Controlled P-F Based Sliding Structures
This study summarizes about three years of research effort related to active control of sliding structures to both harmonic and strong earthquake type motions. This is the first time such...
Bifurcations and Chaos in Structural Control
We study a harmonically forced oscillator with nonlinear soft spring subjected to a linear feedback control with time delay. This system can be written as a three dimensional dynamical...
Routes to Chaos of a Vertically Rotating Pendulum
Each blade of a mechanical shredder may be modeled by a pendulum whose pivot rotates in a vertical circle. The transition to chaos of small periodic motion about radial lines us the driving...
Effect of Active Control on Closely Spaced Natural Frequencies
Current problems in structural control involve structures with closely spaced natural frequencies (M.J. Balas, 1983). The purpose of this paper is to show how control affects a structure...
Full Scale Application of Active Bracing Systems
A full scale active bracing system has been installed in a structure in Tokyo, Japan. The practical problems associated with the implementation of this system, and the corresponding solutions...
Interaction Effects in the Hybrid Control of Euler-Bernoulli Beams
The effect of viscous and Voigt damping upon the open loop response of simple continua such as Euler-Bernoulli beams is well understood. However, when attempting to control a distributed...
Recent Findings in Active Structural Control
Over the past decade, tremendous advancements have been made in the development of structural control paradigms and in the necessary supporting technologies. The fundamental paradigm that...
Structural Control Under Stochastic Seismic Loads
This paper presents a method of controlling nonlinear and hysteretic civil engineering structures subjected to stochastic earthquake ground excitations. Emphasis is placed on control of...
Inflation Concept Development for Inflatable Lunar Structures
Inflatable structures require mechanical equipment to initiate and maintain inflation. Several inflatable structural shapes and forms have been proposed by a number of different authors....
Performance-Based Evaluation of Lunar Base Construction Equipment and Methods
Existing literature regarding the selection of lunar base construction equipment and methods is heavily dependent upon qualitative measures for evaluation of equipment concepts. Selection...
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