Towards productivity indicators for performance-based façade design in commercial buildings

Decision-making in the façade design process has a significant influence on several aspects of indoor environment, thereby making it a complex and multi-objective optimisation process. There are two principal barriers in the process of indentifying an optimal façade solution. Firstly, most existing indoor environmental evaluation methods do not account for all the indoor environmental quality (IEQ) aspects relevant to façade design. Secondly, the relationship between the physical properties of a particular façade design option and the resulting economic benefits accrued during its service-life is unknown. In this paper, we introduce the bases for establishing relationships between occupant productivity and the combinatorial effects of four key façade-related IEQ aspects, namely, thermal comfort, aural comfort, visual comfort and air quality, on occupant productivity. The proposed framework's potential is tested against seven existing experimental investigations and its applicability is illustrated by a simple façade design example. The proposed approach ultimately aims to provide a quantitative economic measure of alternative façade design options that would be applicable to early design stage. Aspects of the work that require further experimental validation are identified. © 2012 Elsevier Ltd.

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.

The response of piled buildings to deep excavations

This paper explores the influence of the piled foundation on the building response to excavation-induced deformations. The influence of the type of foundation, the position of positive and negative skin friction zones, and the flexibility of the piles is evaluated with respect to both horizontal and vertical soil deformations. Case histories from the Netherlands are included from Amsterdam (North South Line) and Rotterdam (a building adjacent to the Willemspoortunnel). Most of the buildings are founded on timber piles ranging in length from 12-17 m. Conclusions are drawn about the interaction between the piled building and the soil deformation. © 2012 Taylor & Francis Group.

The response of buildings to movements induced by deep excavations

Deep excavations and tunnelling can cause ground movements that affect buildings within their influence zone. The current approach for building damage assessment is based on tensile strains estimated from the deflection ratio and the horizontal strains at the building foundation. For tunnelling-induced deformations, Potts & Addenbrooke (1997) suggested a method to estimate the building response from greenfield conditions using the relative building stiffness. However, there is not much guidance for building response to excavation-induced movements. This paper presents a numerical study on the response of buildings to movements caused by deep excavations in soft clays, and proposes design guidance to estimate the deflection ratio and the horizontal strains of the building from the building stiffness. © 2012 Taylor & Francis Group.

The response of buildings to tunnelling: A case study

The response of buildings to tunnelling induced ground movements is an area of great importance for many urban tunnelling projects. This paper presents the response of two buildings to the construction of a 12 m diameter sprayed concrete lining (SCL) tunnel with face reinforcement, in Italy. Soil and structure displacements were monitored through extensive instrumentation. The settlement response of the two buildings was found to differ significantly, demonstrating both flexible and rigid response mechanisms. Comparison of the building settlement profiles with greenfield settlements enables the soil structure interaction to be quantified. Encouraging agreement between the modification to the greenfield settlement profile displayed by buildings and estimates made from existing predictive tools is observed. Potential issues for infrastructure connected to buildings, arising from the embedment of rigid buildings into the soil, are also highlighted. © 2012 Taylor & Francis Group.

Centrifuge modelling of the response of buildings to tunnelling

Understanding how buildings respond to tunnelling induced ground movements is an area of great importance for many urban tunnelling projects. Testing described in this paper aims to investigate soil structure interaction effects by observing the response of elastic and non elastic beams of varying stiffness and geometry 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 mechanisms. Results demonstrate that buildings can significantly modify greenfield ground movements in both the vertical and horizontal planes. The magnitude of the modification is shown to be strongly dependent on the relative building stiffness. It is also shown that negligible horizontal strains are transferred into the model buildings. This can have significant implications for commonly adopted damage assessment methods. © 2012 Taylor & Francis Group.

The horizontal response of framed buildings on individual footings to excavation-induced movements

Deep excavations and tunnelling can cause ground movements that affect buildings within their influence zone. The current approach for building damage assessment is based on tensile strains estimated from the deflection ratio and the horizontal strains at the building foundation. This paper examines the significance of horizontal strains in buildings on individual footings. The first part of the paper presents a case study of a framed building in Singapore which was subjected to the effects of bored tunnelling, where significant horizontal strains were observed. The second part of the paper suggests a method to relate the horizontal strains induced in a building to the stiffness of the frame structure. Using a combination of simplified structural analysis and finite element models, design guidance is proposed to estimate excavation-induced horizontal strains in frame buildings on individual footings. © 2012 Taylor & Francis Group.

Energy use of buildings at urban scale: A case study of london school buildings

The diversity of non-domestic buildings at urban scale poses a number of difficulties to develop building stock models. This research proposes an engineering-based bottom-up stock model in a probabilistic manner to address these issues. School buildings are used for illustrating the application of this probabilistic method. Two sampling-based global sensitivity methods are used to identify key factors affecting building energy performance. The sensitivity analysis methods can also create statistical regression models for inverse analysis, which are used to estimate input information for building stock energy models. The effects of different energy saving measures are analysed by changing these building stock input distributions.

Building performance simulation for the management of thermal performance risks in buildings subject to climate change

This paper reports on research that uses building performance simulation and uncertainty analysis to assess the risks that projected climate change poses to the thermal performance of buildings, and to their critical functions. The work takes meteorological climate change predictions as a starting point, but also takes into account developments and uncertainties in technology, occupancy, intervention and renovation, and others. Four cases are studied in depth to explore the prospects of the quantification of said climate change risks. The research concludes that quantification of the risks posed by climate change is possible, but only with many restrictive assumptions on the input side.

Modelling and Fragility Analysis of Non-Ductile Reinforced Concrete Buildings in Low-to-Moderate Seismic Zones

Reinforced concrete buildings in low-to-moderate seismic zones are often designed only for gravity loads in accordance with the non-seismic detailing provisions. Deficient detailing of columns and beam-column joints can lead to unpredictable brittle failures even under moderate earthquakes. Therefore, a reliable estimate of structural response is required for the seismic evaluation of these structures. For this purpose, analytical models for both interior and exterior slab-beam-column subassemblages and for a 1/3 scale model frame were implemented into the nonlinear finite element platform OpenSees. Comparison between the analytical results and experimental data available in the literature is carried out using nonlinear pushover analyses and nonlinear time history analysis for the subassemblages and the model frame, respectively. Furthermore, the seismic fragility assessment of reinforced concrete buildings is performed on a set of non-ductile frames using nonlinear time history analyses. The fragility curves, which are developed for various damage states for the maximum interstory drift ratio are characterized in terms of peak ground acceleration and spectral acceleration using a suite of ground motions representative of the seismic hazard in the region.

A conceptual framework for future-proofing the energy performance of buildings

This paper presents a review undertaken to understand the concept of 'future-proofing' the energy performance of buildings. The long lifecycles of the building stock, the impacts of climate change and the requirements for low carbon development underline the need for long-term thinking from the early design stages. 'Future-proofing' is an emerging research agenda with currently no widely accepted definition amongst scholars and building professionals. In this paper, it refers to design processes that accommodate explicitly full lifecycle perspectives and energy trends and drivers by at least 2050, when selecting energy efficient measures and low carbon technologies. A knowledge map is introduced, which explores the key axes (or attributes) for achieving a 'future-proofed' energy design; namely, coverage of sustainability issues, lifecycle thinking, and accommodating risks and uncertainties that affect the energy consumption. It is concluded that further research is needed so that established building energy assessment methods are refined to better incorporate future-proofing. The study follows an interdisciplinary approach and is targeted at design teams with aspirations to achieve resilient and flexible low-energy buildings over the long-term. © 2012 Elsevier Ltd.

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 buildingswhichemitnetzerocarbonduringtheiroperationallifetime.However,inordertomeetthe80%targetitisnecessary 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 restrictembodiedcarbon,anumberofdifferentapproacheshavebeenmade.Thereareseveralexistingdatabasesofembodied carbonandembodiedenergy.Mostprovidedataforthematerialextractionandmanufacturingonly,the‘cradletofactorygate’ 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.