Integrated InSAR monitoring and structural assessment of tunnelling-induced building deformations

Structural deformation monitoring is crucial for the identification of early signs of tunnelling-induced damage to adjacent structures and for the improvement of current damage assessment procedures. Satellite multi-temporal interferometric synthetic aperture radar (MT-InSAR) techniques enable measurement of building displacements over time...

Building response to tunnelling- and excavation-induced ground movements: using transfer functions to review the limiting tensile strain method

In this paper, limiting tensile strain method (LTSM) is reviewed, and advantages and disadvantages resulted from the simplicity of this method are examined in the light of the findings of the existing experimental and numerical studies. Using the viewpoint of the transfer functions for the LTSM, a more independent sight for the interpretation of...

Ageing effects of alkali-silica reaction in concrete structures

The alkali-silica reaction (ASR) is a long-term deterioration process, which produces a hydrophilic and expansive gel causing damage. The ASR acts on concrete as an ageing phenomenon, modifying the material on the basis of its stress state. Focussing on the mechanical degradation of concrete, estimated trends for the mechanical properties in...

In-situ fatigue damage assessment of carbon-fibre reinforced polymer structures using advanced experimental techniques

This study focused on the in-situ fatigue damage assessment of open-hole carbon/epoxy coupons using Acoustic Emission (AE) and Digital Image Correlation (DIC) techniques. Constant amplitude fatigue tests were performed and the main objective was to investigate the damage process, the degradation process of the fatigue modules and to identify...

Damage functions for the vulnerability assessment of masonry buildings subjected to tunneling

This paper describes a new framework for the assessment of potential damage caused by tunneling-induced settlement to surface masonry buildings. Finite element models in two and three dimensions, validated through comparison with experimental results and field observations, are used to investigate the main factors governing the structural...

3D numerical analysis of tunnelling induced damage: The influence of the alignment of a masonry building with the tunnel axis

The development of infrastructure in major cities often involves tunnelling, which can cause damage to existing structures. Therefore, these projects require a careful prediction of the risk of settlement induced damage. The simplified approach of current methods cannot account for three-dimensional structural aspects of buildings, which can...

Coupled analysis of building damage due to tunneling

Excavation works in urban areas require a preliminary risk damage assessment. In historical cities, the prediction of building response to settlements is necessary to reduce the risk of damage of the architectural heritage. The current method used to predict the building damage due to ground deformations is the Limiting Tensile Strain Method ...

Variation in load experience: A re-analysis of Fokker F27 and Foker F28 operational acceleration data

Fatigue meter data obtained during operational flights of Fokker F27 and Fokker F28 aircraft were re-processed and analyzed to study the variation in load experience between different aircraft of the same type. The Data covered about 470000 flights, made by 101 aircraft of 51 different operators. A simple algorithm was developed to quantify the...

Variability of fatigue crack growth properties for 2024-T3 aluminium alloy

Discussions between D-BAA and the NLR have shown that significant variability in fatigue crack growth properties is possible for the industry standard damage tolerant aluminium alloy, 2024-T3 sheet. This is important for two reasons: (1) design assumptions and (2) comparisons of different candidate materials, such as 6013-T6, with 2024-T3....

Damage assessment and preservation of an Egyptian silver vase (300 - 200 B.C.)

An Egyptian metal vase from the Ptolemaic period was investigated metallurgically and fractographically. The metal is nearly pure silver, and chemical analysis indicates it was obtained from the cupellation of lead. Despite its high purity (in archaeological terms) the metal is severely cracked and embrittled, with fractures mainly along grain...

Aircraft corrosion and fatigue damage assessment (USAF ASIP Publication)

This paper reviews currently available information on corrosion and fatigue in aircraft as a background to discussing the assessment of corrosion and fatigue damage. The main topics are: - aircraft operating environments and loads - corrosion - fatigue - corrosion and fatigue - corrosion and fatigue damage assessment. Aircraft structures are...

A damage tolerance study conducted with structure relevant specimens

A preliminary investigation is reported of the development of a Structure Relevant (SR-) specimen, which maintains the essential features of a stiffened panel configuration, in order to study damage growth behavior at limited cost. Several SR-specimens were fabricated, damage was applied, either through impacts or by the insertion of artificial...

Monitoring load experience of individual aircraft

Paper presented at the 17th ICAS Congress, Stockholm, September 1990. The actual service load experience of aircraft may differ appreciably from design assumptions. The necessity to monitor service loads is generally recognized now for military aircraft. This paper starts with a general review of the overall life management procedure commonly...

Delamination growth in improved carbon composites under constant amplitude fatigue loading

Constant amplitude tension-compression fatigue tests were performed on notched (± 45, 02, 90, 02)s coupon specimens of the composite systems T300/F593, T400H/6376, T800H//5245C and IM6/APC-2. Delamination damage growth as a function of the number of fatigue cycles was determined using the ultrasonic C-scan technique. Considering the resistance...

Prediction of fatigue crack growth

As an introduction the practical significance of fatigue crack growth life prediction is related to the service life, the inspection period and the fracture control requirements. Then different aspects of fatigue crack growth in metallic materials are discussed in more detail. Important effects such as chemical environment, short cracks, crack...