scholarly journals Sensitivity analysis of the influences of mortar aging and loss on the structural performance of masonry arch aqueducts

2021 ◽  
Vol 300 ◽  
pp. 01022
Author(s):  
Jiang Hu ◽  
Fuheng Ma
Keyword(s):  
Structural Integrity ◽  
Significant Proportion ◽  
Deep Understanding ◽  
Sensitivity Analyses ◽  
Structural Safety ◽  
Stone Masonry ◽  
Structural Performance ◽  
Structural Behaviour ◽  
Masonry Arch ◽  
And Performance

As commonly used canal system structures, masonry arch aqueducts constitute a significant proportion of Chinese old irrigation infrastructures. Most of these existing aqueducts are well over 50 years old, the deterioration of their constituent materials over time, as well as the development of other defects, significantly affects the mechanical responses of these structures. A deep understanding on the dominant factors that influence the structural safety behaviour of masonry arch aqueducts is essential for determining maintenance and strengthening strategies. Taken the Zhaimen masonry aqueduct in the famous Red Flag Canal as a case study, sensitivity analyses of the influences of mortar aging and loss on the structural performance were carried out. The aqueduct, with unknown geometric dimensions and uncertain physical and mechanical parameters, has defects such as the arch ring detaching from the upper structure and the continuous loss and falling of mortar. The discrete element method (DEM) was employed to analyse the structural behaviour. The results show that the upper structure and the supporting structure are stable under the no bond strength condition. When the mortar is lost locally, the vault position is the most dangerous, followed by the arch shoulder, and then the arch foot part. The mortar loss, manifested as denseness reduction, greatly affects the aqueduct stability. Conversely, the deterioration of the mechanical properties of the mortar, caused by weathering and Calcium ion dissolution due to ambient environment and aqueduct leakage, has relatively little impact on the structural safety. Supplementary grouting of the mortar between the stone masonry should be timely carried out to maintain the structural integrity to ensure the overall stability of the structure. The proposed approach can provide a reference to structural diagnosis and performance assessment for similar structures.

scholarly journals Static and Impact Response of a Single-Span Stone Masonry Arch

2021 ◽  
Vol 6 (12) ◽  
pp. 178
Author(s):  
Bora Pulatsu ◽  
Semih Gonen ◽  
Paulo B. Lourenço
Keyword(s):  
High Strain ◽  
Numerical Models ◽  
Contact Stiffness ◽  
Friction Angle ◽  
Masonry Wall ◽  
Impact Response ◽  
Sensitivity Analyses ◽  
Stone Masonry ◽  
Masonry Structures ◽  
Masonry Arch

Unreinforced masonry structures are susceptible to man-made hazards such as impact and blast loading. However, the literature on this subject mainly focuses on masonry wall behavior, and there is a knowledge gap about the behavior of masonry arches under high-strain loading. In this context, this research aims to investigate both quasistatic and impact response of a dry-joint stone masonry arch using the discrete element method. Rigid blocks with noncohesive joint models are adopted to simulate dry-joint assemblages. First, the employed modeling strategy is validated utilizing the available experimental findings, and then sensitivity analyses are performed for both static and impact loading, considering the effect of joint friction angle, contact stiffness, and damping parameters. The outcomes of this research strengthen the existing knowledge in the literature regarding the computational modeling of masonry structures that are subjected to usual and extreme loading conditions. The results highlight that applied discontinuum-based numerical models are more sensitive to stiffness parameters in high-strain loading than static analysis.

scholarly journals A Review of Influence of Various Types of Structural Bracing to the Structural Performance of Buildings

2018 ◽  
Vol 34 ◽  
pp. 01010
Author(s):  
S.M. Razak ◽  
T.C. Kong ◽  
N.Z. Zainol ◽  
A. Adnan ◽  
M. Azimi
Keyword(s):  
Structural Damage ◽  
Structural Performance ◽  
Structural Behaviour ◽  
Lateral Drift ◽  
High Rise ◽  
Different Types ◽  
History Of ◽  
Technical Details ◽  
And Performance ◽  
Stability Of Structure

Excessive lateral drift can contribute significantly towards crack formation, leading to structural damage. The structural damage will in turn reduce the capacity of the structure and weaken it from the intended design capacity. Generally, lateral drift is more pronounced in higher and longer structure, such as high rise buildings and bridges. A typical method employed to control lateral drift is structural bracing, which works by increasing stiffness and stability of structure. This paper reviews the influence of various types of structural bracing to structural performance of buildings. The history of structural bracing is visited and the differences between numerous structural bracing in term of suitability to different types of buildings and loading, mechanisms, technical details, advantages and limitations, and the overall effect on the structural behaviour and performance are dissected. Proper and efficient structural bracing is pertinent for each high rise building as this will lead towards safer, sustainable and more economical buildings, which are cheaper to maintain throughout the life of the buildings in the future.

scholarly journals Structural Diagnosis and Performance Assessment of Existing Masonry Aqueducts with Unknown Geometry

2021 ◽  
Author(s):  
Jiang Hu ◽  
Fuheng Ma
Keyword(s):  
Performance Assessment ◽  
Laser Scanning ◽  
Mechanical Performance ◽  
Structural Safety ◽  
Measurement Information ◽  
Masonry Arch ◽  
Weathering Processes ◽  
Assessment Approach ◽  
And Performance ◽  
Structural Diagnosis

Masonry arch aqueducts, as important hydraulic structures, constitute an meaningful part of old irrigation infrastructures in China. The constituent materials deteriorate over time, caused by weathering processes and the defect development, influences the mechanical performance of these structures. The paper presents a comprehensive approach to evaluate the structural safety of an old masonry aqueduct with uncertain mechanical parameters and unknown geometric dimensions. This approach employed the 3D terrestrial laser scanning (TLS) to measure the geometric dimensions, and the discrete element analysis (DEM) to analyze the current operational behaviour state of the masonry aqueduct. As a case study, the Zhaimen masonry arch aqueduct in the famous Red Flag Canal, operating for more than 50 years, was investigated in this study. Obvious defects, such as the continuous loss and falling of mortar and the arch ring detaching, appeared in this old aqueduct. The TLS measurement information was used to construct a DEM model. Then this numerical model was applied to analyze the current performance of the exiting masonry arch aqueduct. The results show that the upper structure and the supporting structure can still be stable assuming that the mortar with no bond strength. In other words, the deterioration of the mortar, due to natural weathering and Calcium ion dissolution caused by natural environment and leakage, would not have a fatal impact on the structural safety. The proposed structural diagnosis and performance assessment approach can provide a reference to safety evaluation for similar masonry arch aqueducts.

scholarly journals Suggestion of Safety Certification Standards and Performance Evaluation Methods for Fabricated Mobile Scaffold in South Korea

2021 ◽  
Vol 19 (1) ◽  
pp. 133
Author(s):  
Heesoo Kim ◽  
Jeonghyeon Lim ◽  
Jeong-Hun Won ◽  
Jun-Hyuk Kwon ◽  
Seungjun Kim
Keyword(s):  
Performance Evaluation ◽  
Carrying Capacity ◽  
Evaluation Methods ◽  
Structural Safety ◽  
Structural Performance ◽  
Load Carrying Capacity ◽  
Safety Certification ◽  
Load Carrying ◽  
Certification Standards ◽  
And Performance

At construction sites, various types of temporary equipment and structures are used for safety and work efficiency. However, various temporary equipment-related accidents frequently occur for many reasons, including inappropriate installation, usage, and material and structural imperfections. A mobile scaffold is one of the most commonly used indoor temporary equipment for work in high places. In general, the main structural members of the mobile scaffold, such as the mainframes, horizontal members, braces, caster wheels, outriggers, and handrails, are installed on the construction site for this purpose. This means that the load-carrying capacity of the equipment can vary depending on the assembly details. In Korea, there are safety certification standards applied for frequently used temporary equipment, such as scaffolds and shoring. However, the standards concern the strength criteria for the member itself, rather than the global load-carrying capacity. Therefore, it is difficult to review whether the fabricated mobile scaffold has sufficient load-carrying capacity, or to confirm the structural safety considering the various uncertainties affecting the structural performance. In this study, rational safety certification standards and evaluation methods are suggested for fabricated mobile scaffolds. The suggested safety certification standards present structure-level criteria for checking the load-carrying capacity, horizontal stiffness of the structure, and overturning risk. It is expected that the structural performance for safety can be directly checked based on the suggested safety certification standards and performance evaluation methods during the safety certification stage.

THE USE OF HISTORICAL DATA IN ACCOUNTING RESEARCH: THE CASE OF THE AMERICAN SUGAR REFINING COMPANY

1997 ◽  
Vol 24 (2) ◽  
pp. 1-24 ◽  
Author(s):  
Robert Bricker ◽  
Kevin Brown
Keyword(s):  
Capital Market ◽  
Historical Data ◽  
Abnormal Returns ◽  
Deep Understanding ◽  
Historical Record ◽  
Historical Period ◽  
Financial Condition ◽  
A Value ◽  
Time Period ◽  
And Performance

In 1908, the American Sugar Refining Company (ASR) reversed its long-held policy of secrecy as to its financial condition and performance. Prior work, applying contemporary capital market methods to ASR security price data of that period, has suggested a value to ASR shareholders of this policy reversal. This paper examines the historical record of that time and presents additional evidence on this matter, particularly in terms of identifying potentially confounding events occurring during the period under study. The results of this analysis suggest a difficulty in attributing observed abnormal returns to ASR's secrecy policy reversal on the basis of the results obtained from applying capital markets methods. This analysis is useful for scholars interested in applying modern capital market methods to historical data. It highlights the significance of the possible effects of contemporaneous historical events, focuses attention on the importance of a deep understanding of the historical period studied, and suggests a value in combining historical and empirical-markets methods to gain a richer understanding of the events and conditions in the time period under study.

Debonding Behaviors of CFRP Strengthened RC Beams with Weak Interfaces

2013 ◽  
Vol 351-352 ◽  
pp. 587-591
Author(s):  
Sen Li ◽  
Xiao Gang Wang ◽  
Xin Gang Zhou
Keyword(s):  
Tensile Strain ◽  
Structural Integrity ◽  
Structural Performance ◽  
Rc Beams ◽  
Test Results ◽  
Weak Interface ◽  
Premature Rupture ◽  
Loading Process ◽  
Interface Effects

Debonding behaviors of CFRP strengthened RC beams were experimentally investigated under the influence of weak interfaces, which are induced either by defective bonding of replaced cover or expansive cracks. Shown by test results, weak interfaces impaired considerably the structural integrity of strengthening systems during loading, and easily led to CFRP debonding failure. U-strips worked effectively in preventing the integral debonding and guarantee the structural performance of flexural sheets. However, local cover delamination in the loading process and premature rupture of flexural CFRP could still take place due to the weak interface effects. Therefore, allowable tensile strain of flexural CFRP should be reduced, and more strict confinement and anchorage measures should be taken in this case.

scholarly journals Experimental Investigations on Ultimate Behavior of Fabricated Mobile Scaffolds

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 851
Author(s):  
Heesoo Kim ◽  
Jeonghyeon Lim ◽  
Jeonghwa Lee ◽  
Young Jong Kang ◽  
Seungjun Kim
Keyword(s):  
Evaluation Methods ◽  
System Level ◽  
Structural Safety ◽  
Structural Performance ◽  
Experimental Investigations ◽  
Rigorous Evaluation ◽  
Effective Evaluation ◽  
Test Models ◽  
Behavior Characteristics ◽  
Structural Behaviors

A fabricated mobile scaffold has various components, including vertical members, horizontal members, braces, work plates, and castor wheels. In Korea, the structural performance of each member must be validated based on member-level structural safety criteria; this means that rigorous evaluation methods are required to secure the system-level structural safety of the fabricated mobile scaffold. To suggest rational system-level structural safety criteria and effective evaluation methods, the characteristics of the structural behaviors of the assembled structure must be investigated first. Unlike other temporary equipment, it is a product that requires convenience of use and ease of movement. Therefore, to secure the safety and usability of the structure, it is necessary to evaluate the ultimate behavior of a mobile scaffold fabricated with various material and structural types. In an experimental study, the ultimate mode and load-bearing capacity were investigated, and the appropriateness of the required performance of the mobile scaffold was reviewed. Three types of experimental test models with different materials (steel and aluminum) and stories (single-story and three-story erection) were selected and examined for vertical loads. Based on the experimental results, the ultimate behavior characteristics of the fabricated mobile scaffold were analyzed, and the ultimate load was identified.

Structural Integrity System Based on an Object-Oriented Activity- and Product Model

1993 ◽  
Author(s):  
Morten Lovstad ◽  
Tor G. Syvertsen
Keyword(s):  
Computational Models ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Physical Structure ◽  
Gas Production ◽  
Structural Safety ◽  
Actual State ◽  
Product Model ◽  
The North ◽  
Analysis Models

Abstract Huge steel or reinforced concrete structures in deep waters support the installations for oil and gas production in the North Sea. Steady operations in a hostile environment require that structural safety and integrity is maintained. For rapid evaluation and assessment of structural integrity in case of modifications or urgency situations, Structural Integrity Systems are established, comprising computational models and structural analysis programs. A major problem for structural assessment at short notice is to keep the analysis models updated and consistent with the actual state of the physical structure and the loadings. This paper proposes a layered approach for model integration, which enable maintenance of the models at a high level, from which detailed analysis models are derived in a consistent manner.

Dance Imagery for Technique and Performance

2014 ◽  
Author(s):  
Eric Franklin
Keyword(s):  
Deep Understanding ◽  
The Body ◽  
Artistic Expression ◽  
Contemporary Dance ◽  
Improve Technique ◽  
Dance Class ◽  
Dance Improvisation ◽  
Dance Imagery ◽  
And Performance ◽  
Dance Educators

Renowned master teacher Eric Franklin has thoroughly updated his classic text, Dance Imagery for Technique and Performance, providing dancers and dance educators with a deep understanding of how they can use imagery to improve their dancing and artistic expression in class and in performance. These features are new to this edition: • Two chapters include background, history, theory, and uses of imagery. • 294 exercises offer dancers and dance educators greater opportunities to experience how imagery can enhance technique and performance. • 133 illustrations facilitate the use of imagery to improve technique, artistic expression, and performance. Franklin provides hundreds of imagery exercises to refine improvisation, technique, and choreography. The 295 illustrations cover the major topics in the book, showing exercises to use in technique, artistic expression, and performance. In addition, Franklin supplies imagery exercises that can restore and regenerate the body through massage, touch, and stretching. And he offers guidance in using imagery to convey information about a dancer’s steps and to clarify the intent and content of movement. This new edition of Dance Imagery for Technique and Performance can be used with Franklin’s Dynamic Alignment Through Imagery, Second Edition, or on its own. Either way, readers will learn how to combine technical expertise with imagery skills to enrich their performance, and they will discover methods they can use to explore how imagery connects with dance improvisation and technique. Dance Imagery for Technique and Performance uses improvisation exercises to help readers investigate new inner landscapes to create and communicate various movement qualities, provides guidelines for applying imagery in the dance class, and helps dancers expand their repertoire of expressiveness in technique and performance across ballet, modern, and contemporary dance. This expanded edition of Dance Imagery for Technique and Performance supplies imagery tools for enhancing or preparing for performance, and it introduces the importance of imagery in dancing and teaching dance. Franklin’s method of using imagery in dance is displayed throughout this lavishly illustrated book, and the research from scientific and dance literature that supports Franklin’s method is detailed. The text, exercises, and illustrations make this book a practical resource for dancers and dance educators alike.

scholarly journals Implementation of the structural performance factor (Sp) within a displacement-based design framework

2018 ◽  
Vol 51 (3) ◽  
pp. 159-165 ◽  
Author(s):  
Dion Marriott
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Structural Performance ◽  
Integration Time ◽  
Design Framework ◽  
Base Shear ◽  
Structural Behaviour ◽  
Performance Factor ◽  
Design Response Spectrum ◽  
Displacement Based

This paper discusses the application of the Structural Performance factor (SP) within a Direct Displacement-Based Design framework (Direct-DBD). As stated within the New Zealand loadings standard, NZS1170.5:2004 [1], the SP factor is a base shear multiplier (reduction factor) for ductile structures, i.e. as the design ductility increases, the SP factor reduces. The SP factor is intended to acknowledge the better-than-expected structural behaviour of ductile systems (both strength, and ductility capacity) by accounting for attributes of response that designers are unable to reliably estimate. The SP factor also recognizes the less dependable seismic performance of non-ductile structures, by permitting less of a reduction (a larger SP factor) for non-ductile structures. Within a traditional force-based design framework the SP factor can be applied to either the design response spectrum (a seismic hazard/demand multiplier), or as a base shear multiplier at the end of design (structural capacity multiplier) – either of these two approaches will yield an identical design in terms of the required design base shear and computed ULS displacement/drift demands. However, these two approaches yield very different outcomes within a Direct-DBD framework – in particular, if SP is applied to the seismic demand, the design base shear is effectively multiplied by (SP)2 (i.e. a two-fold reduction). This paper presents a “DBD-corrected” SP factor to be applied to the design response spectrum in Direct-DBD in order to achieve the intent of the SP factor as it applies to force-based design. The proposed DBD-corrected SP factor is attractive in that it is identical to the SP relationship applied to the elastic site hazard spectrum C(T) for numerical integration time history method of analysis within NZS 1170.5:2004 [1], SP,DDBD = (1+SP)/2.

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