Strengthening of Masonry Structures: Current National and International Approaches for Qualification and Design

2019 ◽  
Vol 817 ◽  
pp. 501-506
Author(s):  
Antonio Bonati ◽  
Annalisa Franco ◽  
Orsola Coppola ◽  
Giuseppina de Luca
Keyword(s):  
Composite Materials ◽  
Composite System ◽  
Unreinforced Masonry ◽  
Seismic Events ◽  
Masonry Structures ◽  
International Level ◽  
Public Authorities ◽  
Composite Systems ◽  
The Past ◽  
Inorganic Matrix

The strong seismic events that have occurred in Italy during the past few years have shown the vulnerability of unreinforced masonry structures all over the country. The growing interest in the use of composite materials as a fast and effective way for structural strengthening pushed Italian public authorities to define common rules for qualification and design. Different guidelines are being developed at the national, but also at the international level, considering the different composite systems currently present on the market, generally constituted by continuous fibres in the form of fabrics or meshes embedded in a polymeric or inorganic matrix. The paper will summarize and compare the various assessment and design approaches of the composite system, highlighting the different aspects which characterize national and international procedures of certification.

Development and Calibration of an Earthquake Fatality Function

2003 ◽  
Vol 19 (3) ◽  
pp. 605-633 ◽  
Author(s):  
John M. Nichols ◽  
James E. Beavers
Keyword(s):  
United States ◽  
Twentieth Century ◽  
The United States ◽  
Unreinforced Masonry ◽  
Earthquake Magnitude ◽  
United States Geological Survey ◽  
Seismic Events ◽  
Calibration Data ◽  
Masonry Structures ◽  
Remote Locations

Structures present a risk during seismic events from partial or full collapse that can cause death and injury to the occupants. The United States Geological Survey (USGS) has collated data on deaths from and magnitudes of earthquakes. These data have not previously been analyzed to establish any relationships between fatality tolls or fatality rates in different earthquakes. An investigation of the fatality catalogue establishes a bounding function for the twentieth-century fatality data using the USGS assigned earthquake magnitude as the dependent variable. A simple equation was established and calibrated to relate the fatalities in earthquakes having tolls lower than the bounding function to the bounding function. This equation and the calibration data, essentially for unreinforced masonry and timber-framed buildings, provides a procedure for estimating fatality counts in future theoretical events with a specific combination of circumstances. Potential uses of the fatality function with further refinement are economic analysis of seismic mitigation alternatives for unreinforced masonry structures. Current uses of the fatality function can be for real-time estimating of fatalities in earthquakes in remote locations, and estimating fatality counts in future earthquakes for planning purposes.

Criteria for the Repair of Damage to Masonry Walls of Buildings Affected by Earthquakes Using Composite Materials with Inorganic Matrix

2017 ◽  
Vol 747 ◽  
pp. 670-677 ◽  
Author(s):  
Antonio La Tegola ◽  
Walter Mera
Keyword(s):  
Composite Materials ◽  
Energy Dissipation ◽  
Organic Matrix ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Cementitious Composite ◽  
Brittle Behavior ◽  
Frequent Use ◽  
Metallic Mesh ◽  
Inorganic Matrix

After the inspections to the damage caused by the last earthquake in Ecuador, and considering the construction typologies of reinforced concrete buildings in Guayaquil and Manta (Ecuador), in order to rebuild or repair the masonry walls we must resort to composite materials with inorganic matrix (cementitious). Composite materials in FRP with an organic matrix (epoxy) are not appropriate because, with an increase of strength they have a brittle behavior, therefore without possibility of energy dissipation not having the ductility provided by a metallic mesh or cobalt-metallic mesh, which have the advantage of using it with a cementitious matrix of frequent use in the current technology. Since the photographic records and the design of those masonry structures allow determining in detail the dynamics of the damage, it is possible to add to the theoretical analysis an experimental verification on the behavior of masonry walls with reinforced plastering with FRP or with metallic mesh with inorganic matrix under seismic actions.

Damage to masonry buildings caused by the 1995 Hyogo-ken Nanbu (Kobe, Japan) earthquake

1996 ◽  
Vol 23 (3) ◽  
pp. 797-807 ◽  
Author(s):  
Michel Bruneau ◽  
Koji Yoshimura
Keyword(s):  
Unreinforced Masonry ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Design Codes ◽  
Epicentral Area ◽  
The Past ◽  
Masonry Construction ◽  
Kobe Earthquake ◽  
Reinforced Masonry ◽  
A Minor

The seismic performance of the few masonry structures present in the Kobe area and subjected to the severe Hyogo-ken Nanbu earthquake is a minor concern when compared to the overwhelming damage suffered by other types of structures. However, in order to dispel the myth that masonry structures are nonexistent in Japan as well as a few other misconceptions, and for the sake of completeness within the concerted multipaper reporting effort on the Hyogo-ken Nanbu (Kobe) earthquake by the Canadian reconnaissance team which visited the epicentral area of this earthquake, a brief description of the past and present state of masonry construction in Japan is first presented, followed by a short description of the damage to unreinforced masonry buildings, masonry garden-walls, and nonstructural masonry elements, as observed by the authors during their visits to the Kobe area. Key words: earthquake, seismic, masonry, buildings, bearing walls, unreinforced masonry, reinforced masonry, failures, design codes.

scholarly journals Coseismic fault-slip distribution of the 2019 Ridgecrest Mw6.4 and Mw7.1 earthquakes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yang Gao ◽  
HuRong Duan ◽  
YongZhi Zhang ◽  
JiaYing Chen ◽  
HeTing Jian ◽  
...  
Keyword(s):  
Strike Slip ◽  
Fault Slip ◽  
Slip Distribution ◽  
Synthetic Aperture ◽  
Seismic Events ◽  
Interferometric Synthetic Aperture Radar ◽  
The Past ◽  
Dextral Strike Slip Fault ◽  
Fault Slip Distribution ◽  
Dextral Strike Slip

AbstractThe 2019 Ridgecrest, California seismic sequence, including an Mw6.4 foreshock and Mw7.1 mainshock, represent the largest regional seismic events within the past 20 years. To obtain accurate coseismic fault-slip distribution, we used precise positioning data of small earthquakes from January 2019 to October 2020 to determine the dip parameters of the eight fault geometry, and used the Interferometric Synthetic Aperture Radar (InSAR) data processed by Xu et al. (Seismol Res Lett 91(4):1979–1985, 2020) at UCSD to constrain inversion of the fault-slip distribution of both earthquakes. The results showed that all faults were sinistral strike-slips with minor dip-slip components, exception for dextral strike-slip fault F2. Fault-slip mainly occurred at depths of 0–12 km, with a maximum slip of 3.0 m. The F1 fault contained two slip peaks located at 2 km of fault S4 and 6 km of fault S5 depth, the latter being located directly above the Mw7.1hypocenter. Two slip peaks with maximum slip of 1.5 m located 8 and 20 km from the SW endpoint of the F2 fault were also identified, and the latter corresponds to the Mw6.4 earthquake. We also analyzed the influence of different inversion parameters on the fault slip distribution, and found that the slip momentum smoothing condition was more suitable for the inversion of the earthquakes slip distribution than the stress-drop smoothing condition.

An Introduction to the Impact Behaviour of Polymer Composites Using Simplified Beam Models

1998 ◽  
Vol 26 (2) ◽  
pp. 89-110 ◽  
Author(s):  
R. A. W. Mines
Keyword(s):  
Composite Materials ◽  
Undergraduate Students ◽  
Progressive Collapse ◽  
Structural Response ◽  
Sandwich Beams ◽  
Three Point Bending ◽  
The Past ◽  
Structural Case ◽  
The University ◽  
The Impact

The paper describes a final-year undergraduate course that has been taught at the University of Liverpool for the past three years. The main aims of the course are to introduce the student to the design of structures using multi-component (composite) materials and to the performance of such structures under impact loading. Given the complexity of generalized composite behaviour and of structural crashworthiness, a simple structural case is considered, namely, a beam subject to three-point bending. A feature of the course is that not only is linear structural response considered but also non-linear (progressive) structural collapse is covered. The course is split into four parts, namely: (i) analysis of composite laminae, (ii) analysis of laminated beams, (iii) local and global effects in sandwich beams, and (iv) post-failure and progressive collapse of sandwich beams. Static and impact loadings are considered. Comments are made on how the theories are simplified and communicated to the undergraduate students.

The Design of Composite Materials For Electro-Mechanical and Electro-Thermal Applications.

1983 ◽  
Vol 24 ◽  
Author(s):  
L. E. Cross
Keyword(s):  
Composite Materials ◽  
Figure Of Merit ◽  
Poisson Ratio ◽  
Dielectric Behavior ◽  
Thermal Mass ◽  
Secondary Effects ◽  
Pressure Sensing ◽  
Composite Systems ◽  
Reinforced Composite ◽  
Composite Microstructure

ABSTRACTIn composite materials for electro-mechanical applications, the importance of the mode in which the constituent phases are interconnected (connectivity) was stressed. For the tensor properties of mechanical, piezoelectric, and dielectric behavior, controlling the manner in which fields and fluxes thread through the composite can make orders of magnitude change in the coupled properties.Examples were drawn from piezoelectric ceramic:polymer composites for uniaxial and hydrostatic (hydrophone) pressure sensing where the 1:3 connected transversely reinforced composite can be shown to exhibit a figure of merit more than 103 that of the piezoceramic phase alone. In these systems, the importance of poisson ratio effects in the polymer phase were evident, and some new composite systems where the hydrostatic stiffness of the elastomer phases may be better exploited were considered.In electro-thermal applications such as in pyroelectric composites, the requirements of small-size and low-thermal mass put rigorous limits upon the scale of the composite microstructure. Techniques which achieve the appropriate scaling were described and preliminary data showed strong enhancement of the secondary effects in these composites were presented.

scholarly journals Modelling imperfections in unreinforced masonry structures: Discrete element simulations and scale model experiments of a pavilion vault

2021 ◽  
Vol 228 ◽  
pp. 111499
Author(s):  
Alessandro Dell'Endice ◽  
Antonino Iannuzzo ◽  
Matthew J. DeJong ◽  
Tom Van Mele ◽  
Philippe Block
Keyword(s):  
Discrete Element ◽  
Unreinforced Masonry ◽  
Scale Model ◽  
Masonry Structures ◽  
Model Experiments ◽  
Discrete Element Simulations

The Benefits of a Seismic Retrofit Program for Commercial Unreinforced Masonry Structures: Salt Lake County, Utah

1993 ◽  
Vol 9 (1) ◽  
pp. 1-10
Author(s):  
Philip C. Emmi ◽  
Carl A. Horton
Keyword(s):  
Salt Lake ◽  
Exposure Period ◽  
Seismic Retrofit ◽  
Unreinforced Masonry ◽  
Masonry Structures ◽  
Damage Functions ◽  
Lake County ◽  
Evaluation Time ◽  
Comparative Risk ◽  
Uniform Code

This paper assesses the benefits of a seismic retrofit program for commercial unreinforced masonry structures (CURMs) in Salt Lake County, Utah. A comparative risk assessment embedded in a geographic information systems is the method used. A policy evaluation time horizon of twenty years is set. Future rates of demolition and rehabilitation, with and without a retrofit policy, are assumed. Damage functions for ordinary and retrofitted URMs are used to assess losses having a 10 percent chance of being exceeded over a 50-year exposure period. With a retrofit program, expected losses are reduced by 57 percent or more than a quarter billion dollars when compared to the no-policy scenario. Expected injuries and fatalities are reduced by more than 80 percent. These are minimal benefits expected from enforcement of the seismic provisions of the Uniform Code of Building Conservation.

The Analysis and Synthesis of Vibrating Systems

1954 ◽  
Vol 58 (526) ◽  
pp. 703-719 ◽  
Author(s):  
R. E. D. Bishop
Keyword(s):  
Composite System ◽  
Frequency Equation ◽  
Computational Effort ◽  
Analytical Treatment ◽  
Principal Mode ◽  
Oscillatory Systems ◽  
Composite Systems ◽  
Analysis And Synthesis ◽  
Simple Systems ◽  
Vibrating Systems

SummaryComplicated oscillatory systems may be broken down into component “ sub-systems ” for the purpose of vibration analysis. These will generally submit more readily to analytical treatment. After an introduction to the concept of receptance, the principles underlying this form of analysis are reviewed.The dynamical properties of simple systems (in the form of their receptances) may be tabulated. By this means the properties of a complicated system may be found by first analysing it into convenient sub-systems and then extracting the properties of the latter from a suitable table. A catalogue of this sort is given for the particular case of conservative torsional systems with finite freedom.The properties of the composite system which may be readily found in this way are (i) its receptances and (ii) its frequency equation. Tables are given of expressions for these in terms of the receptances of the component sub-systems. All of the tables may easily be extended. The tabulated receptances may also be used for determining relative displacements during free vibration in any principal mode.A method of presenting information on the vibration characteristics of machinery, which is effectively due to Carter, is illustrated by means of an example. More general adoption by manufacturers of this method (which requires no more computational effort than must normally be made) would lead to enormous savings of labour in calculating natural frequencies of composite systems.

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