Influence of Masonry Properties on Confinement: A Mechanical Model

2014 ◽  
Vol 624 ◽  
pp. 299-306 ◽  
Author(s):  
Gian Piero Lignola ◽  
Andrea Prota ◽  
Gaetano Manfredi
Keyword(s):  
Mechanical Model ◽  
Research Effort ◽  
Theoretical Work ◽  
Design Guidelines ◽  
Masonry Structures ◽  
Solid Mechanic ◽  
Large Variability ◽  
General Validity ◽  
Confined Masonry ◽  
Confinement Model

Design provisions for the repair, retrofitting, and rehabilitation of existing masonry structures are not always available and included in International and National Building Codes. Due to the extremely large variability in masonry performances, equations of general validity cannot be provided, namely relationships suitable for confinement of every masonry type, as it is done for concrete. Large amount of results obtained for concrete led to consolidated design guidelines. Despite the great research effort in the experimental field on masonry, considerable theoretical work is still needed to fully outline a definitive analytical model to predict the behavior of FRP confined masonry. In this study, a mechanically based confinement model is proposed based on mechanical parameters able to differentiate similar masonry types and to highlight that they present different confinement performance. The most relevant parameters are the compressive and tensile strength of unconfined masonry and they are discussed in the framework of solid mechanic based models based on triaxial plasticity and calibrated experimentally. The proposed approach can then be extended to other masonry types.

Strength of Minimum Structure Platforms Under Ship Impact

2004 ◽  
Vol 126 (4) ◽  
pp. 368-375 ◽  
Author(s):  
Gage S. Grewal ◽  
Marcus M. K. Lee
Keyword(s):  
Numerical Investigation ◽  
Ultimate Strength ◽  
Energy Absorption ◽  
Structural Integrity ◽  
Research Effort ◽  
Design Guidelines ◽  
Design Issues ◽  
Plastic Energy ◽  
Ship Collision ◽  
Important Design

This paper presents the findings of a numerical investigation into the strength of minimum structure platforms subject to a ship impact. The study has identified important design issues that should be addressed in order to improve the survivability and continued serviceability of minimum structures after a ship impact. It was found that, due to a lack of research effort, design guidelines governing ship impact on minimum structures are lacking in comparison with conventional jacket platforms. In particular, requirements governing the minimum amount of plastic energy absorption in minimum structures are not clearly defined. Ship impact analyses were therefore carried out in order to compare their structural integrity with that for a jacket under ship collision conditions and to evaluate the effects on their ultimate strength. The study not only established any degradation of system strength, but has also determined the amount of plastic energy absorption under various impact scenarios.

scholarly journals Analysis of confined masonry with Strut and Tie models

2020 ◽  
Vol 323 ◽  
pp. 02002
Author(s):  
Łukasz Drobiec ◽  
Wojciech Mazur ◽  
Tomasz Rybarczyk
Keyword(s):  
Reinforced Concrete ◽  
Full Scale ◽  
Masonry Walls ◽  
Reinforced Concrete Structures ◽  
Masonry Structures ◽  
Test Results ◽  
Confined Masonry ◽  
Good Compliance ◽  
Strut And Tie ◽  
Calculation Results

Strut & Tie (S-T) models are used quite commonly for the analysis of reinforced concrete structures and in the calculation of masonry structures. Creating the S-T model of the confined masonry is slightly different from models of reinforced concrete or models of classic masonry structures. These models should take into account different stiffness of concrete and masonry. This article proposes a Strut & Tie model for the analysis of confined masonry. The results of calculations were compared with the results of tests of full scale masonry walls with and without opening. Good compliance of the calculation results of S-T models with the test results was obtained.

Nonlinear seismic evaluation of confined masonry structures using equivalent truss model

2021 ◽  
Vol 248 ◽  
pp. 113114
Author(s):  
Nikita Rankawat ◽  
Svetlana Brzev ◽  
Sudhir K. Jain ◽  
Juan José Pérez Gavilán
Keyword(s):  
Masonry Structures ◽  
Seismic Evaluation ◽  
Confined Masonry ◽  
Truss Model

Statistical analysis of the bonding properties of the fabric-reinforced cementitious matrix for strengthening masonry structures

2021 ◽  
pp. 136943322110179
Author(s):  
Lei Jing ◽  
Shiping Yin ◽  
Farhad Aslani ◽  
Shuang Liu
Keyword(s):  
Regression Analysis ◽  
Statistical Analysis ◽  
Masonry Structures ◽  
Test Results ◽  
Prediction Formula ◽  
Large Variability ◽  
Testing Procedures ◽  
Cementitious Matrix ◽  
Bonding Properties ◽  
Fabric Reinforced Cementitious Matrix

The fabric-reinforced cementitious matrix (FRCM) has been extensively studied and applied for the strengthening of masonry structures. Special attention needs to be given to the bonding properties between the FRCM and masonry substrate for strengthening applications. This paper presents a statistical analysis of the bonding properties based on the available literature. First, the collected test results were discussed in terms of the interfacial failure mode. Second, the factors influencing the ultimate bond load were analysed based on the different failure modes, and a corresponding prediction formula was further determined via regression analysis for interfacial debonding and slippage failures. Then, the characteristic values of the ultimate bond load were determined via a probabilistic method. Finally, the fracture energy for the slippage failure at the fabric-matrix interface was analysed, and a corresponding prediction formula was obtained via regression analysis. Additionally, some of the collected test results present higher dispersion due to the large variability of the FRCM material properties and the differences in the testing procedures used by different institutions. More studies are needed to improve the reliability of the proposed procedure.

Nonlinear Analysis for Masonry under Monotonic and Low Cyclic Loading

2011 ◽  
Vol 94-96 ◽  
pp. 406-415 ◽  
Author(s):  
Yan Huang ◽  
Ming Hui Kan ◽  
Zi Fa Wang
Keyword(s):  
Cyclic Loading ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Vertical Load ◽  
Closed Crack ◽  
Transfer Coefficients ◽  
Confined Masonry ◽  
2008 Wenchuan Earthquake ◽  
Shear Property ◽  
Low Cyclic Loading

Abstract: Confined masonry with tie columns and ring-beams was adopted during the reconstruction in the rural and suburban areas in Sichuan Province after the 2008 Wenchuan Earthquake. Based on the results of the sample tests of building material such as clay brick, cement mortar, steel and concrete in reconstruction and the analysis on the characteristics and features using Solid65 elements in ANSYS, the shear property of joints in masonry structures under different vertical load (σ∕fm) is numerically simulated. Comparing the experimental results with the numerical ones, the proposed values for the shear transfer coefficients for open and closed crack of Solid65 elements for simulating masonry structures are given. The seismic performance of confined masonry walls (strengthened by tie column and ring-beam, etc.) and unconfined masonry walls with different stress condition (σ∕fm) under low cyclic load are discussed. Results show that, under monotonic loading, confined masonry walls have better performance for displacement and load corresponding to the occurrence of the first crack as well as for the ultimate load and ductility, although the energy dissipating ability of unconfined walls under low cyclic loading increases with vertical load (σ∕fm) at low stress level. The results demonstrate that confined walls are greatly enhanced by strengthening measures such as tie column and ring-beams.

Experimental Study on Seismic Failure Modes of Confined Masonry Structures with Different Enhancements

2017 ◽  
Vol 747 ◽  
pp. 594-603 ◽  
Author(s):  
Hu Xu ◽  
Hao Wu ◽  
Cristina Gentilini ◽  
Qi Wang Su ◽  
Shi Chun Zhao
Keyword(s):  
Experimental Study ◽  
Failure Mode ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Experimental Results ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Structural Collapse ◽  
Static Loads ◽  
Confined Masonry

In this study, confined masonry specimens with regular arranged openings are tested in order to study the influence of different enhancements of the columns on seismic failure modes. In particular, five brick masonry walls and three half-scale two-storey masonry structures are tested under quasi-static loads. The experimental results show that increasing column ratio improves the seismic behavior of the wall specimens to some extent, but an excessive reinforcement ratio of the columns decreases the ductility. The global failure mode of the two-storey masonry structures is modified by inserting iron wires in the mortar bed joints, improving the structural collapse resistant capacity effectively.

scholarly journals QUANTUM MATTERS: PHYSICS BEYOND LANDAU'S PARADIGMS

2006 ◽  
Vol 20 (19) ◽  
pp. 2603-2611 ◽  
Author(s):  
T. SENTHIL
Keyword(s):  
Particle Physics ◽  
Order Parameter ◽  
Theoretical Work ◽  
Many Body ◽  
General Validity ◽  
Quasiparticle Excitation ◽  
Body State ◽  
Growing Body ◽  
The Many ◽  
Theoretical Developments

Central to our understanding of quantum many particle physics are two ideas due to Landau. The first is the notion of the electron as a well-defined quasiparticle excitation in the many body state. The second is that of the order parameter to distinguish different states of matter. Experiments in a number of correlated materials raise serious suspicions about the general validity of either notion. A growing body of theoretical work has confirmed these suspicions, and explored physics beyond Landau's paradigms. This article provides an overview of some of these theoretical developments.

Simplified Methods for Improving the Blast Resistance of Cold-Formed Steel Walls

2011 ◽  
Vol 82 ◽  
pp. 515-520 ◽  
Author(s):  
Bryan Bewick ◽  
Casey O'Laughlin ◽  
Eric Williamson
Keyword(s):  
Blast Resistance ◽  
Research Effort ◽  
Design Guidelines ◽  
Attractive Alternative ◽  
Testing Program ◽  
Large Blast ◽  
Construction Methods ◽  
Cold Formed Steel ◽  
Steel Stud ◽  
Wall System

In recent years, cold-formed steel stud walls have become an attractive alternative to wood stud walls. Relative to wood, cold-formed steel is highly ductile, sustainable, and unaffected by insects, mold or rot. Research has demonstrated that cold-formed steel stud walls can perform well when subjected to large blast threats, but such performance has depended upon specially designed fasteners that are expensive to manufacture and require experienced workers to install properly. Despite the potential performance of these types of wall systems when specialized fasteners are used, current U.S. Department of Defense design guidelines for conventionally constructed steel stud walls use acceptability criteria that are much more conservative than wood stud walls due to the lack of data available. Thus, the goal of the current research effort is to develop techniques for mitigating large blast threats acting against steel stud walls using conventional construction methods and materials. The research includes controlled laboratory tests that are intended to identify the various failure mechanisms that can occur for different combinations of wall system parameters. Variables considered in the testing program include stud and track section properties, stud-to-track connection details, stud orientation and wall layout, and sheathing system properties. Based on the results obtained from the testing program and supporting analyses, the most promising wall system designs will be identified, and design guidance will be developed. Final designs will be tested under actual blast loads to verify performance and to ensure that wall systems behave as desired.

Behaviour of Minimum Structure Platforms Under Ship Impact

2004 ◽  
Author(s):  
M. M. K. Lee ◽  
G. S. Grewal
Keyword(s):  
Numerical Investigation ◽  
Ultimate Strength ◽  
Energy Absorption ◽  
Structural Integrity ◽  
Research Effort ◽  
Design Guidelines ◽  
Design Issues ◽  
Plastic Energy ◽  
Ship Collision ◽  
Important Design

This paper presents the findings of a numerical investigation into the strength of minimum structure platforms subject to a ship impact. The study has identified important design issues that should be addressed in order to improve the survivability and continued serviceability of minimum structures after a ship impact. It was found that, due to a lack of research effort, design guidelines governing ship impact on minimum structures are lacking in comparison with conventional jacket platforms. In particular, requirements governing the minimum amount of plastic energy absorption in minimum structures are not clearly defined. Ship impact analyses were therefore carried out in order to compare their structural integrity with that for a jacket under ship collision conditions and to evaluate the effects on their ultimate strength. The study not only established any degradation of system strength, but has also determined the amount of plastic energy absorption under various impact scenarios.

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