| Salt-Fog Accelerated Testing of Glass Fiber Reinforced Polymer Composites |
01 DEC 2002 |
53 pages |
| Authors:
Arsenio Caceres; Robert M. Jamond; Theresa A. Hoffard; L. J. Malvar; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
|
 | The objective of this project was to determine the durability under accelerated salt-fog exposure of six commercially available composites. These composites included glass- reinforced vinylesters, polyesters, phenolics, and an epoxy. Durability was measured mainly in terms of the loss of elastic modulus and flexural strength after exposure. In order to accelerate aging, the specimens were subjected to temperatures of 95F (35C), 120F (49C), and 160F (71C) for one, two and ... |
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| Literature Review of Durability of Composites in Reinforced Concrete |
AUG 96 |
26 pages |
| Authors:
L. J. Malvar; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
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| Many fiber reinforced plastics (FRP's) have excellent corrosion resistance properties and can be engineered to have mechanical properties comparable to steel. These characteristics have promoted their use in many structural applications all over the world. Although the short-term mechanical properties of these materials are usually well documented, long-term durability issues still remain. Some of these issues are hereby summarized, mostly for the case of reinforced concrete applications. Experimental observations indicate ... |
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| Unidirectional Core-Shell Hybrids for Concrete Reinforcement - A preliminary Study |
FEB 94 |
28 pages |
| Authors:
L. J. Malvar; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
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| Fiber-reinforced plastic (FRP) bars are currently being used to replace steel bars as concrete reinforcement. For non-prestressed applications, these FRP bars exhibit a relatively low modulus of elasticity and a lack of ductility. This report shows that two-fiber hybrid composites can be optimized to obtain a rebar with a modulus of elasticity equal to steel, as well as a pseudo-plastic behavior. This pseudo-plastic behavior corresponds to the gradual transfer of ... |
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| Bond Stress-Slip Characteristics of FRP Rebars |
FEB 94 |
51 pages |
| Authors:
L. J. Malvar; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
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| The bond characteristics of four different types of glass fiber- reinforced plastic (GFRP) rebars with different surface deformations were analyzed experimentally. Local bond stress-slip data, as well as bond stress- radial deformation data, needed for constitutive modeling of the interface mechanics, were obtained for varying levels of confining pressure. In addition to bond stress and slip, radial stress and radial deformation were considered fundamental variables needed to provide for configuration-independent ... |
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| Three-Dimensional Finite Element Analysis of Explosive Safety Facilities - A Technology Assessment |
DEC 92 |
152 pages |
| Authors:
T. A. Shugar; T. J. Holland; L. J. Malvar; D. A. Doi; NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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| To establish research requirements for development of modern, specialized software for computational structural dynamics in support of Navy explosive safety facilities, NCEL conducted baseline studies to assess commercial or currently available general purpose computer programs. Two widely available general purpose computer programs for three-dimensional nonlinear dynamic finite element analysis were applied to three types of reinforced concrete structures of interest to Navy explosive safety facility designers: (1) a novel cylindrical ... |
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| Advanced Finite Element Analysis of Drydocks and Waterfront Facilities. A Technology Assessment |
OCT 1991 |
149 pages |
| Authors:
T. A. Shugar; T. J. Holland; L. J. Malvar; NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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| Various models of Navy waterfront structures are presented and employed to assess their effectiveness in predicting the vulnerability of these systems to operational and earthquake loads. The emphasis is on application of three dimensional finite element models to reinforced concrete structural analysis. Results indicate that dynamic analysis is important in the calculation of the structural response of both a drydock and a blocked vessel in drydock. The primary natural frequencies ... |
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| Bond of Reinforcement Under Controlled Confinement |
JUN 91 |
46 pages |
| Authors:
L. J. Malvar; NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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| Twelve specimens were tested to determine the local bond stress-slip characteristics of a No. 6 rebar embedded in a 3-inch diameter concrete cylinder. Radial confining stress around the concrete specimen and radial deformation were assumed to be fundamental variables, together with bond stress and slip, needed to properly describe the interface behavior. Configuration independent bond stress-slip, relationships for a short five-lug embedded length were obtained for various degrees of confining ... |
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| Lateral Load Distribution in One-Way Flat Slabs |
MAY 91 |
65 pages |
| Authors:
G. E. Warren; L. J. Malvar; NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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| Results of laboratory model tests, inservice pier tests, classical plate theory, and finite element analyses provide the basis for changes in Military Handbook 1025/1 addressing flat slab pier dock design to distribute truck crane outrigger loads. The concentrated load distribution efficiency of Navy pier slabs can be doubled over current AASHTO allowables. For pier deck designs where large, truck-mounted cranes dominate load requirements, this will result in higher load capacity, ... |
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| Mixed Mode Crack Propagation in Concrete |
FEB 90 |
43 pages |
| Authors:
L. J. Malvar; G. E. Warren; NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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| Two smeared crack approaches to fracture of concrete in mixed mode are implemented in two-dimensional nonlinear concrete elements: (1) tensile stress transfer across cracks and (2) tensile plus shear stress transfer across cracks. To corroborate the analytical model a notched beam under mixed mode loading is then analyzed. In both cases, the stiffnesses normal and parallel to the crack were modified to insure a positive definite stiffness matrix. Stresses were ... |
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| Analytical Modeling of Reinforced Concrete in Tension |
APR 89 |
51 pages |
| Authors:
L. J. Malvar; G. E. Warren; NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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| A smeared crack approach to fracture of concrete in mode I was implemented in the finite element program ADINA. Nonlinear concrete elements with tensile cracking were modified to include tensile strain softening. When an element at an integration point cracks, the stiffness perpendicular to the crack is reduced to zero and the tensile stress across it is set as a function of the crack opening. Equilibrium iterations were implemented to ... |
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