Search

The AIAG established the MSA, 4th Edition, as an international guideline to determine if the selected measurement system is capable and can be used for the intended purpose. The MSA guideline provides a practical basis for decision-making and is applied in both scientific and industrial contexts. In addition to the MSA, the Guide to the Expression of Uncertainty in Measurement (GUM) has standardized the determination of measurement uncertainties at an international level. This paper provides a practical example of using a surface comparator to demonstrate the limitations of the MSA for roughness parameters. Additionally, it presents a new method for assessing the capability of a measuring system for roughness measurements by considering the aspects from MSA and GUM. This work considers all information, distinguishing between existing and experimentally generated data. The experimental investigations for the application of the new method were carried out using a confocal laser scanning measuring microscope. The approach presents a new practical opportunity for both science and industry.

Full-scale axial load tests were performed on five screw injection piles founded in medium-dense to dense sand at a site in Delft, the Netherlands. Each pile was instrumented with distributed fiber-optic sensors along its full length, giving detailed insights into the shaft and base response under compression loading. The paper focuses on the pile base response and combines the test results with a newly compiled database of instrumented load tests on screw displacement piles in sand. Given the range of screw displacement piles on the market, the influence of different installation methods and pile geometries on the base resistance can be assessed through the database. In summary, the analysis showed that all screw displacement pile types tended to mobilize base capacities similar to bored or nondisplacement piles. Despite high variability in the database, no significant trend with pile geometry, such as length or diameter, was evident. [ABSTRACT FROM AUTHOR]

Three driven precast, four driven cast-in-situ, and four screw injection piles were installed and tested in dense to very dense sand at a site in the Netherlands. Each pile was instrumented with two types of fiber optic sensors and tested under axial compression. Through these tests, a comparison could be made of how different installation methods influence the pile base and shaft response. For example, large residual base stresses were measured in the driven precast piles after installation. Of the three pile types tested, the driven precast piles also reached the highest base stresses, mobilizing their full base resistance at comparatively low displacements. The base response of the driven cast-in-situ piles was also like that of a driven precast pile with residual stresses excluded. In contrast, the screw injection piles mobilized much lower ultimate base resistances and with a much lower stiffness. In terms of shaft resistance, the precast piles showed friction fatigue effects in line with existing models, but this effect was not evident for the driven cast-in-situ or screw injection piles. Finally, shaft and base resistances measured in the dense to very dense sand layers were greater than limiting resistances prescribed in several design standards. By taking this into consideration in design standards, the results would help reduce some of the overconservatism present in design and consequently reduce the financial and environmental cost of pile manufacturing and installation. [ABSTRACT FROM AUTHOR]