Effects of solution exposure on the combined axial-shear behaviour of unidirectional CFRP rods

In fibre reinforced polymer (FRP) prestressed concrete applications, an FRP tendon must sustain high axial tensile stresses and, if cracks occur, additional dowel forces. The tendon may also be exposed to solutions and so the combined axial-shear stress performance after long-term environmental exposure is important. Experiments were conducted to investigate the combined axial-shear stress failure envelope for unidirectional carbon FRP tendons which had been exposed to either water, salt water or concrete pore solution at 60 °C for approximately 18 months. The underlying load resisting mechanisms were found to depend on the loading configuration, restraint effects and the initial stress state. When saturated, CFRP tendons are likely to exhibit a reduced shear stiffness. However, the ultimate limit state appeared to be fibre-dominated and was therefore less susceptible to reductions due to solution uptake effects. © 2012 Elsevier Ltd. All rights reserved.

Reliability analysis of deep excavation based on a semi-empirical approach

The design and construction of deep excavations in urban environment is often governed by serviceability limit state related to the risk of damage to adjacent buildings. In current practice, the assessment of excavation-induced building damage has focused on a deterministic approach. This paper presents a component/system reliability analysis framework to assess the probability that specified threshold design criteria for multiple serviceability limit states are exceeded. A recently developed Bayesian probabilistic framework is used to update the predictions of ground movements in the later stages of excavation based on the recorded deformation measurements. An example is presented to show how the serviceability performance for excavation problems can be assessed based on the component/system reliability analysis. © 2011 ASCE.

Lateral and Axial Capacity of Monopiles for Offshore Wind Turbines

Offshore wind has enormous worldwide potential to generate increasing amounts of clean, renewable energy. Monopile foundations are considered to be viable in supporting larger offshore wind turbines in shallow to medium depth waters. In this paper, the lateral and axial response of monopiles installed in undrained clays of varying shear strength and stiffness is investigated using three-dimensional finite element analysis. A combination of axial and lateral loads expected at an offshore wind farm located in a water depth of 30 m has been used in the analysis. Numerically derived monopile axial capacities will be compared to those calculated using an established method in the literature. In addition, the lateral monopile capacity will be determined at ultimate limit state and compared to that at the serviceability limit state. Through a parametric study, it will be shown that with the exception of extremely high axial loads that border on monopile axial capacities, variation in axial loads does not have a significant effect on the ultimate lateral capacity and lateral displacement of monopiles. © 2013 Indian Geotechnical Society.

Defining product-service network configurations and location roles: A current and future state analysis framework for international engineering operations

Many manufacturing firms have developed a service dimension to their product portfolio. In response to this growing trend of servitisation, organisations, often involved in complex, long-lifecycle product-service system (PSS) provision, need to reconfigure their global engineering networks to support integrated PSS offerings. Drawing on parallel concepts in 'production' networks, the idea of 'location role' now becomes increasingly complex, in terms of service delivery. As new markets develop, locations in a specific region may need to grow/adapt engineering service 'competencies' along the value chain, from design and build to support and service, in order to serve future location-specific requirements and, potentially, those requirements of the overall network. The purpose of this paper is to advance understanding of how best to design complex multi-organisational engineering service networks, through extension of the 'production' network location role concept to a PSS context, capturing both traditional engineering 'design and build' and engineering 'service' requirements. Copyright © 2012 Inderscience Enterprises Ltd.