The response of buildings to tunnelling: A case study

A case study of the response of two buildings to the construction of a 12 m diameter tunnel excavated by conventional method, in Italy, is studied. The 12 m diameter tunnel was constructed carrying out reinforcement of the tunnel face and around the crown prior to excavation and installation of the temporary sprayed concrete lining and the permanent reinforced concrete lining. Reflective prisms, placed at first floor level around the perimeter of the building facades, allowed building settlements to be measured. Ground settlements between the two buildings were measured using BRE type settlement studs. Extensive protective measures were adopted to maintain stability of the tunnel excavation and to reduce ground movements. The number of horizontal jet grout columns installed into the tunnel face was reduced over the course of the project. Results from CPT tests indicate that the undrained shear strength at the tunnel axis is around 120 kPa. SPT and undrained unconsolidated (UU) triaxial tests indicate lower strengths of around 80 kPa, although this may be due to sample disturbance.

Designing better buildings

Chapter 1 Design as a value generator Sebastian Macmillan ... has never been a better time to address the issue of design quality and the value of design. ...

A Comparative Review of Existing Data and Methodologies for Calculating Embodied Energy and Carbon of Buildings

In the Climate Change Act of 2008 the UK Government pledged to reduce carbon emissions by 80% by 2050. As one step towards this, regulations are being introduced requiring all new buildings to be ‘zero carbon’ by 2019. These are defined as buildings which emit net zero carbon during their operational lifetime. However, in order to meet the 80% target it is necessary to reduce the carbon emitted during the whole life-cycle of buildings, including that emitted during the processes of construction. These elements make up the ‘embodied carbon’ of the building. While there are no regulations yet in place to restrict embodied carbon, a number of different approaches have been made. There are several existing databases of embodied carbon and embodied energy. Most provide data for the material extraction and manufacturing only, the ‘cradle to factory gate’ phase. In addition to the databases, various software tools have been developed to calculate embodied energy and carbon of individual buildings. A third source of data comes from the research literature, in which individual life cycle analyses of buildings are reported. This paper provides a comprehensive review, comparing and assessing data sources, boundaries and methodologies. The paper concludes that the wide variations in these aspects produce incomparable results. It highlights the areas where existing data is reliable, and where new data and more precise methods are needed. This comprehensive review will guide the future development of a consistent and transparent database and software tool to calculate the embodied energy and carbon of buildings.

Sustainable buildings need integrated teams

This report is intended to contribute to strengthening the work of the Government, the Strategic Forum and the Specialist Engineering Alliance in bringing about a more integrated and a more sustainable industry. Its aim is to examine the potential for improving the sustainability of the built environment through an integrated approach to procurement and delivery, in which the role of the specialist engineering sector is recognised for its vital ability to improve building performance. Based on wide ranging knowledge and expertise across the construction sector, it puts forward a vision for sustainable buildings and sets out the actions needed from Government, clients, consultants, contractors and manufacturers to ensure the vision is realised. The report complements the Strategy for Sustainable Construction published by the Department for Business, Enterprise and Regulatory Reform (June 2008).

Centrifuge modelling of the response of buildings to tunnelling

The response of surface structures to tunnelling induced ground movements is an area of great importance for any urban tunnelling project. Testing described in this paper aims to investigate soil structure interaction effects by observing the response of aluminium beams of varying stiffness to tunnelling, using the 8 m diameter beam centrifuge at Cambridge University. Soil and structure displacements are extensively monitored through a photo imaging technique which enables a detailed analysis of the interaction behaviour. Results to date indicate that the relative structure-soil stiffness is the governing factor in determining how a structure will respond to tunnelling. This parameter is highly dependent on both the structure and soil stiffness. It is also shown that contrary to common assumptions in the literature, negligible axial strains are transferred into the structure. This paper outlines the results of the research to date. © 2010 Taylor & Francis Group, London.

Management of thermal performance risks in buildings subject to climate change

This article reports on the use of building performance simulation to quantify the risks that climate change poses to the thermal performance of buildings, and to their critical functions. Through a number of case studies the article demonstrates that any prediction of the probable thermal building performance on the long timeframes inherent in climate change comes with very large uncertainties. The same cases are used to illustrate that assessing the consequences of predicted change is problematic, since the functions that the building provides in themselves often are a moving target. The article concludes that quantification of the risks posed by climate change is possible, but only with many restrictions. Further research that is needed to move to more effective discussion about risk acceptance and risk abatement for specific buildings is identified. © 2012 Elsevier Ltd.

A validation of commercial flow solver performance on hybridised octree meshes

In recent years we have been developing a meshing system which is aimed at eliminating the bottleneck represented by building meshes for real-world, complex turbomachinery configurations. This system is based on a rapid octree meshing technology which is then made conformal to the bodies present. The objective of this paper is to demonstrate that this class of mesh is not only very fast to produce but also fit-for-purpose in the sense that simulations generated with third-party commercial flow solvers like Fluent have the same accuracy as those performed on more conventional meshes. A range of standard examples and test cases will be presented. Copyright © 2011 by ASME.

A probabilistic energy model for non-domestic building sectors applied to analysis of school buildings in greater London

The diversity of non-domestic buildings at urban scale poses a number of difficulties to develop models for large scale analysis of the stock. This research proposes a probabilistic, engineering-based, bottom-up model to address these issues. In a recent study we classified London's non-domestic buildings based on the service they provide, such as offices, retail premise, and schools, and proposed the creation of one probabilistic representational model per building type. This paper investigates techniques for the development of such models. The representational model is a statistical surrogate of a dynamic energy simulation (ES) model. We first identify the main parameters affecting energy consumption in a particular building sector/type by using sampling-based global sensitivity analysis methods, and then generate statistical surrogate models of the dynamic ES model within the dominant model parameters. Given a sample of actual energy consumption for that sector, we use the surrogate model to infer the distribution of model parameters by inverse analysis. The inferred distributions of input parameters are able to quantify the relative benefits of alternative energy saving measures on an entire building sector with requisite quantification of uncertainties. Secondary school buildings are used for illustrating the application of this probabilistic method. © 2012 Elsevier B.V. All rights reserved.