Dynamic Effect of Sediment on Dam Hydrodynamics
The dynamic behavior of reservoir sediment during earthquakes is important to an analysis of dam safety when the depth of the water is seriously reduced by the sediment. While the dynamic...
Softening Models for Concrete: Stability and Uniqueness
A microstructurally-based, numerically oriented, fracture-induced softening model for concrete is presented. Rate-dependent evolution equations for microcrack nucleation, growth, and coalescence...
Damage Mechanics Modeling of the Cyclic Behavior of Plain Concrete
The sudden stiffening behavior of concrete under cyclic loading is discussed and the available experimental investigations to delocalize damage is reviewed. A discussion on the applicability...
Determination of In-Situ Stresses From Acoustic Emissions
Acoustic emissions (AE) are microseismic activities that are generated in concrete by cracking and damage. The rate of Acoustic Emissions, called the 'Event Rate', can provide indication...
Evaluating Polymer Concrete Bridge Expansion Joints Using Acoustic Emission
This study is to simulate the acoustic emission (A/E) of polymer concrete bridge expansion joints subjected to controlled representative loads by a rotating test apparatus on a circular...
Detection of Cracks in Reinforced Concrete Cans
The Acoustic Emission Technique (AET) is known as a good possibility for non destructive detection of cracks in metal down to very small dimensions. To use AET for concrete, an efficient...
On the Modelling of Damage Due to Volumic Variations in Cementitious Composites
Two kinds of volumic variations are considered. Those due to thermal gradients on hardened concrete and those due to hydration processes at early ages. Models based on damage mechanics...
Strain-Based Damage Deactivation in Concrete
Motivated by the 'mode I' microcrack opening and closing mechanism, a procedure for the deactivation of the damage is developed. Strain based projection operators are used to negate the...
Anatomy of the Loma Prieta Earthquake Records of Two Steel Buildings Using MIMO System Identification
The Loma Prieta strong-motion records of a 4-story and a 47-story steel building are analyzed using system identification. A time variation study from the 4-story building records reveals...
The Microstructure of Hardened Cement Paste and Concrete
Concrete is a composite material created from a mixture of a binder (hardened portland cement paste) and a filler (fine and coarse aggregates). Like any other composite material the physical...
Computational Framework for 3D Nonlinear Discrete Crack Analysis
Under contract from the Electric Power Research Institute (EPRI) to investigate the applicability of fracture mechanics to concrete dams, the authors are involved in the development of...
Shear Resistance Models for Concrete Bridges
Statistical models are developed for the shear resistance of concrete bridge girders. Two structural types are considered: reinforced concrete T-beams and prestressed concrete AASHTO girders....
An Elastoviscoplastic Model for High Strength Concrete
An elastoviscoplastic model of overstress type is proposed for high-strength concrete in this study. With its viscosity parameters determined with experimental data from the split-Hopkinson-pressure-bar...
Mechanical Properties of High Performance Concretes
This paper presents some of the initial results of a 4-year research project on mechanical properties of high performance concretes with particular reference to highway applications. High...
Scattering of Waves by Steel Reinforcement in Concrete
The application of wave-sensing methods to the non-destructive evaluation of concrete structures requires often the use of simple (or at least tractable) models for the solution of the...
Constitutive Modeling of Slurry Infiltrated Fiber Concrete (SIFCON)
Slurry Infiltrated Fiber CONcrete (SIFCON) is a unique material, containing 5 to 18 percent, by volume, of steel fibers; in contrast, standard Fiber Reinforced Concrete (FRC) usually contains...
Modeling Bond Stress-Slip of Reinforcing Bars Embedded in SIFCON
A brief description is given of the mechanisms associated with the bond shear stress versus slip response of deformed reinforcing bars embedded in slurry infiltrated fiber concrete (SIFCON)....
Investigation of Parametrically-Induced Excitation in Concrete Columns
A mathematical model is developed which accounts for the non-linear material characteristic of concrete members. The axial and transverse motions of concrete columns, are found to be second-order...
Design Codes for Lunar Structures
The American Institute of Steel Construction (AISC) Manual of Steel Construction is a codification for the design and construction of steel structures. It includes information, some tabular...
Genesis: The Creation of a Lunar Base
A lunar basing scenario that utilizes lunar resources to manufacture lunar concrete modules is considered. An eleven year basing program, starting with initial robotic exploration and...
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