A macro-element based practical model for seismic analysis of steel-concrete composite high-rise buildings

This is the post-print version of the final paper published in Engineering Structures. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.Seismic behaviour of steel–concrete composite high-rise buildings, composed of external steel frames (SFs) and internal concrete tube (CT), with rectangular plan is investigated in this paper. A macro-element based model is established for seismic analysis of composite high-rise buildings aiming at predicting their global responses under earthquakes. By employing this macro-element based model, natural frequencies and vibration modes, storey and inter-storey drifts, overturning moments and storey shear forces of composite structures, induced by earthquakes, are able to be obtained with much less computation time and cost compared with using micro-element based analytical models. To validate its efficiency and reliability, the macro-element based model is employed to analyse a 1/20 scaled-down model of a 25-storey steel–concrete composite high-rise building subjected to simulated earthquakes with various intensities through a shaking table. Natural frequencies and storey drifts of the model structure are obtained from numerical analyses and compared with those from shaking table test results. It has been found that the calculated dynamic responses of the composite model structure subjected to minor, basic, major and super strong earthquakes agree reasonably well with those obtained from experiments, suggesting that the proposed macro-element based model is appropriate for inelastic time-history analyse for global responses of steel–concrete composite high-rise structures subjected to earthquakes with satisfactory precision and reliability. This research thus provides a practical model for elastic and inelastic deformation check of high-rise composite buildings under earthquakes.Ministry of Science and Technology of Chin

Environmental impact assessments of the Three Gorges Project in China: issues and interventions

The paper takes China's authoritative Environmental Impact Statement for the Yangzi (Yangtze) Three Gorges Project (TGP) in 1992 as a benchmark against which to evaluate emerging major environmental outcomes since the initial impoundment of the Three Gorges reservoir in 2003. The paper particularly examines five crucial environmental aspects and associated causal factors. The five domains include human resettlement and the carrying capacity of local environments (especially land), water quality, reservoir sedimentation and downstream riverbed erosion, soil erosion, and seismic activity and geological hazards. Lessons from the environmental impact assessments of the TGP are: (1) hydro project planning needs to take place at a broader scale, and a strategic environmental assessment at a broader scale is necessary in advance of individual environmental impact assessments; (2) national policy and planning adjustments need to react quickly to the impact changes of large projects; (3) long-term environmental monitoring systems and joint operations with other large projects in the upstream areas of a river basin should be established, and the cross-impacts of climate change on projects and possible impacts of projects on regional or local climate considered. © 2013 Elsevier B.V.Xibao Xu, Yan Tan, Guishan Yan

The verticality of policy mixes for sustainability transitions: A case study of solar water heating in China

Climate change and sustainable development are the defining challenges of the modern era. The field of sustainability transitions seeks systematic solutions for fundamental transformations of socio-technical systems towards sustainability, and exploring the role of policy mixes has been a central research agenda within the field. In the extant literature, there exists a lack of both conceptual and empirical research on the vertical dimension of policy mixes for sustainability transitions. This study provides a multilevel and evolutionary interpretation of the vertical interactions of policy mixes in the process of industrial path development towards sustainability transitions. An exemplary case of solar water heating (SWH) technology in Shandong Province in China is presented, capturing both the bottom-up and top-down processes of interactions. On the one hand, urban-level policy initiatives can inform higher-level policymaking; on the other hand, national-level priorities can greatly configure policy strategies for lower-level governments. Moreover, as the industry matures, the interactions of multilevel policy mixes evolve from simpler, unidirectional patterns to more complex, bidirectional ones through a vertical policy-learning feedback mechanism. This study generates two important policy implications that extend beyond the Chinese context: first, dynamic vertical interactions between multilevel governments indicate the need to develop more nuanced perspectives on the design of policy mixes; second, policy makers need to hold a more dynamic view of policy mixes by recognizing their temporal and coevolutionary nature through the policy learning process