The ATLAS SemiConductor Tracker (SCT) was built in three sections: a barrel and two end-caps. This paper describes the design, construction and final integration of the barrel section. The barrel is constructed around four nested cylinders that provide a stable and accurate support structure for the 2112 silicon modules and their associated services. The emphasis of this paper is directed at the aspects of engineering design that turned a concept into a fully-functioning detector, as well as the integration and testing of large sub-sections of the final SCT barrel detector. The paper follows the chronology of the construction. The main steps of the assembly are described with the results of intermediate tests. The barrel service components were developed and fabricated in parallel so that a flow of detector modules, cooling loops, opto-harnesses and Frequency-Scanning-Interferometry (FSI) alignment structures could be assembled onto the four cylinders. Once finished, each cylinder was conveyed to the next site for the mounting of modules to form a complete single barrel. Extensive electrical and thermal function tests were carried out on the completed single barrels. In the next stage, the four single barrels and thermal enclosures were combined into the complete SCT barrel detector so that it could be integrated with the Transition Radiation Tracker (TRT) barrel to form the central part of the ATLAS inner detector. Finally, the completed SCT barrel was tested together with the TRT barrel in noise tests and using cosmic rays. KEYWORDS: Particle tracking detectors; Solid state detectors; Detector design and construction technologies and materials; Large detector systems for particle and astroparticle physics.

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The use of bonded fibre-reinforced polymer (FRP) materials for the repair of civil infrastructure is becoming well established. The majority of applications are 'bond critical'; that is, the dominate limit state is affected by the FRP debonding from the substrate. Considerable research has been conducted on the behaviour of FRP bonded to a concrete substrate; however, there is a growing interest in using FRP bonded to a steel substrate. In the former case, bond behaviour is dominated by cohesive failure in the concrete substrate; in the latter, bond is dominated by adhesive behaviour. As a result of not needing to consider substrate failure in the case of FRP-to-steel applications, the FRP may be utilised much more efficiently, provided bond can be maintained. This paper briefly reviews factors affecting bond of FRP-to-steel and presents a relatively simple laboratory test method for assessing bond performance. The method is well suited to comparing performance of different applications, surface preparations, environmental exposures and so on, but also yields quantitative data in the form of the steadystate energy release rate useful for modelling and designing FRP-to-steel bonded interfaces.

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