The role of stress transfer in earthquake occurrence

Nature ◽  
10.1038/45144 ◽  
1999 ◽  
Vol 402 (6762) ◽  
pp. 605-609 ◽  
Author(s):  
Ross S. Stein
Keyword(s):  
Stress Transfer ◽  
Earthquake Occurrence

scholarly journals Some Key Aspects in the Mechanics of Stress Transfer Between SRG and Masonry

2020 ◽  
Vol 10 (20) ◽  
pp. 7303
Author(s):  
Giulia Baietti ◽  
Tommaso D’Antino ◽  
Christian Carloni
Keyword(s):  
Stress Transfer ◽  
High Strength ◽  
Active Role ◽  
Fiber Reinforced ◽  
Suitable Alternative ◽  
Existing Structures ◽  
Direct Shear Tests ◽  
Frp Composites ◽  
Mortar Matrix

The use of composite materials to strengthen masonry structures has become common practice within the civil engineering community. Steel-reinforced grout (SRG), which comprises high-strength steel fibers embedded in a mortar matrix, is part of the family of the fiber-reinforced cementitious matrix (FRCM) composites that represent a suitable alternative to fiber-reinforced polymer (FRP) composites for strengthening existing structures. Although studies on FRCMs have already reached a certain level of maturity, some key issues remain open, such as the role of matrix type and layout, substrate properties, and test rate. This paper focuses on some of these issues. The results of single-lap direct shear tests on masonry blocks strengthened with SRGs are presented to analyze the bond behavior between the composite material and the substrate. Four aspects are considered: (1) the change in the width of the SRG mortar matrix while keeping the width of the fiber sheet fixed; (2) the type of mortar used for the SRG; (3) the influence of the test rate, and (4) the type of substrate (i.e., concrete vs. masonry). The results obtained indicate the active role of the matrix layout and the importance of the test rate, encouraging further investigations to clarify these aspects.

scholarly journals Assessing the role of stress transfer on aftershock locations

2009 ◽  
Vol 114 (B11) ◽  
Author(s):  
Stanislaw Lasocki ◽  
Vassilis G. Karakostas ◽  
Eleftheria E. Papadimitriou
Keyword(s):  
Stress Transfer

A Study of the Fracture Process at the FRP-Masonry Interface: The Role of the Periodic Pattern of Bricks and Mortar Joints

2014 ◽  
Vol 624 ◽  
pp. 611-618 ◽  
Author(s):  
Francesco Focacci ◽  
Christian Carloni
Keyword(s):  
Axial Strain ◽  
Interfacial Shear Stress ◽  
Stress Transfer ◽  
Effective Length ◽  
Periodic Pattern ◽  
Frp Composites ◽  
Load Response ◽  
Reinforced Polymer ◽  
Load Carrying

This paper sheds light into the effect of the periodic pattern of bricks and mortar joints on the load-carrying capacity of the interface between fiber-reinforced polymer (FRP) composites and masonry. Two simplified cohesive material laws are proposed for the FRP-mortar and FRP-brick interfaces, which allow for the computation in closed form of a finite effective bond length Leff of the interfaces. The aforementioned simplified interfacial laws are employed to compute the load response of the FRP-masonry interface, and to obtain the interfacial shear stress, the FRP axial strain, and the slip profiles along the bonded length. The results indicate that length of the stress-transfer zone (LSTZ) of the FRP-masonry interface varies periodically as its location shifts with respect to the position of the mortar joints. Furthermore LSTZ can be different from the effective length of the FRP-brick interface and is influenced by the size of the bricks and mortar joints.

Filament Fragmentation Phenomena

1989 ◽  
Vol 170 ◽  
Author(s):  
Juan C. Figueroa ◽  
Linda S. Schadler ◽  
Campbell Laird
Keyword(s):  
Strain Energy ◽  
Stress Transfer ◽  
Fiber Surface ◽  
Yield Information ◽  
The Matrix ◽  
Two Parameters ◽  
The Relationship

AbstractThe effect of fiber surface treatments on the relationship between the tensile strength of a filament and the shear strength of its interphase is one of the central issues facing composite materials technologists today. We demonstrate here that analysis of fragmentation phenomena in monofilament composites can simultaneously yield information about these two parameters. Characterization of shear stress transfer zones in non-critical fragments has led us to the determination of interphase strength.A phenomenological treatment that highlights the role of the matrix in the fragmentation process is presented here. This analysis considers issues such as the strain energy exchange between a failing fiber and the matrix, as well as interphase relaxation due to the viscoelastic nature of the matrix. Our observations of the fragmentation phenomena in AU4/polycarbonate monofilament composites indicate that the fiber/matrix interaction in this system is governed by micromechanical locking.

scholarly journals Mechanical Stresses Induced by Compression in Castings of the Load-carrying Grate

2016 ◽  
Vol 16 (2) ◽  
pp. 51-54
Author(s):  
J. Słowik ◽  
A. Drotlew ◽  
B. Piekarski
Keyword(s):  
Heat Treatment ◽  
Stress Distribution ◽  
Stress Level ◽  
Stress Transfer ◽  
State Of Stress ◽  
Structure Changes ◽  
Load Carrying ◽  
The Relationship ◽  
Forced Movement

Abstract The main aim of this study was to examine the compression-induced state of stress arising in castings of the guide grates during operation in pusher-type furnaces for heat treatment. The effect of grate compression is caused by its forced movement in the furnace. The introduction of flexible segments to the grate structure changes in a significant way the stress distribution, mainly by decreasing its value, and consequently considerably extends the lifetime of the grates. The stress distribution was examined in the grates with flexible segments arranged crosswise (normal to the direction of the grate compression) and lengthwise (following the direction of force). A regression equation was derived to describe the relationship between the stress level in a row of ribs in the grate and the number of flexible segments of a lengthwise orientation placed in this row. It was found that, regardless of the distribution of the flexible segments in a row, the stress values were similar in all the ribs included in this row, and in a given row of the ribs/flexible segments a similar state of stress prevailed, irrespective of the position of this row in the whole structure of the grate and of the number of the ribs/flexible segments introduced therein. Parts of the grate responsible for the stress transfer were indicated and also parts which play the role of an element bonding the structure.

scholarly journals Decrease of VLF transmitter signal and Chorus-whistler waves before l'Aquila earthquake occurrence

2010 ◽  
Vol 10 (7) ◽  
pp. 1487-1494 ◽  
Author(s):  
M. Y. Boudjada ◽  
K. Schwingenschuh ◽  
R. Döller ◽  
A. Rohznoi ◽  
M. Parrot ◽  
...  
Keyword(s):  
Seismic Event ◽  
Intensity Level ◽  
L’Aquila Earthquake ◽  
Earthquake Occurrence ◽  
The Earth ◽  
Power Spectral ◽  
Before And After ◽  
Vlf Emissions ◽  
The Magnetic Field

Abstract. We investigate the VLF emissions observed by the Instrument Champ Electrique (ICE) experiment onboard the DEMETER micro-satellite. We analyze intensity level variation 10 days before and after the occurrence of l'Aquila earthquake (EQ). We found a clear decrease of the VLF received signal related to ionospheric whistler mode (mainly Chorus emission) and to signal transmitted by the DFY VLF station in Germany, few days (more than one week) before the earthquake. The VLF power spectral density decreases of more than two orders of magnitude until the EQ, and it recovers to normal levels just after the EQ occurrence. The geomagnetic activity is principally weak four days before EQ and increases again one day before l'Aquila seismic event. Our results are discussed in the frame of short- and long-terms earthquakes prediction focusing on the crucial role of the magnetic field of the Earth.

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