This paper presents an investigation into the influence of slope height on the role of vegetation to improve seismic slope stability. Dynamic centrifuge modelling was used to test six slope models with identical soil properties and model slope geometry within different centrifugal acceleration fields (10g and 30g, respectively) representing 1:10 and 1:30 scale slopes, that is, slopes of different height at prototype scale. A three-dimensional (3D) root cluster analogue representing a tap-root system, with root area ratio, root distribution and root length representative of a 1:10 and 1:30 scale tree root cluster (of rooting depth 1·5 m at prototype scale) was modelled using 3D printing techniques. A sequence of earthquake ground motions was applied to each model. The influences of filtering out low-frequency components of the earthquake motion, such as was necessitated at the lowest scaling factor owing to the practical limitations of the earthquake simulator, on dynamic amplification of motions within th...

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Centrifuge modelling of the influence of slope height on the seismic performance of rooted slopes

Abstract A framework for the validation of computational models used to predict seismic response based on observations from seismometer arrays is presented. The framework explicitly accounts for the epistemic uncertainty related to the unknown characteristics of the ‘site’ (i.e. the problem under consideration) and constitutive model parameters. A mathematical framework which makes use of multiple prediction–observation pairs is used to improve the statistical significance of inferences regarding the accuracy and precision of the computational methodology and constitutive model. The benefits of such a formal validation framework include: (i) development of consistent methods for determination of constitutive model parameters; (ii) rigorous, objective, and unbiased assessment of the validity of various constitutive models and computational methodologies for various problem types and ground motion intensities; and (iii) an improved understanding of the uncertainties in computational model assumptions, constitutive models and their parameters, relative to other seismic response uncertainties such as ground motion variability. Details regarding the implementation of such a framework to achieve the aforementioned benefits are also addressed.

Validation of seismic response analyses using seismometer array recordings

The construction of reinforced concrete buildings with unreinforced infill is common practice even in seismically active country such as Bhutan, which is located in high seismic region of Eastern Himalaya. All buildings constructed prior 1998 were constructed without seismic provisions while those constructed after this period adopted seismic codes of neighbouring country, India. However, the codes have limited information on the design of infilled structures besides having differences in architectural requirements which may compound the structural problems. Although the influence of infill on the reinforced concrete framed structures is known, the present seismic codes do not consider it due to the lack of sufficient information. Time history analyses were performed to study the influence of infill on the performance of concrete framed structures. Important parameters were considered and the results presented in a manner that can be used by practitioners. The results show that the influence of infill on the structural performance is significant. The structural responses such as fundamental period, roof displacement, inter-storey drift ratio, stresses in infill wall and structural member forces of beams and column generally reduce, with incorporation of infill wall. The structures designed and constructed with or without seismic provision perform in a similar manner if the infills of high strength are used.

Seismic performance of brick infilled RC frame structures in low and medium rise buildings in Bhutan

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M. Huang

Papers

Soil dynamics and earthquake engineering. Proceedings of sessions of GeoShanghai 2010, Shanghai, China, 3-5 June, 2010.