Low Impact Buildings Research Articles

3D FRP Reinforcement Systems for Concrete Beams: Innovation towards High Performance Concrete Structures.

Despite the advantages of using lightweight and non-corrosive carbon fiber reinforced polymer (CFRP) reinforcements in concrete structures, their widespread adoption has been limited due to concerns regarding the brittle failure of CFRP rupture and its relatively softer load-deflection stiffness. This work offers logical solutions to these two crucial problems: using aggregate coating to strengthen the CFRP-concrete bond and ultimately the load-deflection stiffness, and using CFRP-concrete debonding propagation to create pseudo-ductile behavior. Subsequently, the concrete cracking behavior, the apparent CFRP modulus with aggregates, and the post-peak capacity and deflection of three-dimensional (3D) CFRP-reinforced concrete are all described by equations derived from experiments. These formulas will be helpful in the future design of non-prismatic concrete components for low-impact building projects. The potential of this innovative design scheme in terms of increased capacity and deflections with less concrete material is demonstrated through comparisons between non-prismatic CFRP-reinforced concrete and measured steel reinforced equivalency.

Potential of contemporary earth architecture for low impact building in Belgium

Earth architecture during the 21st century has resurfaced worldwide as a sustainable, low environmental impact material with expressive aesthetics and textures. Contemporary projects attempt to modernize the traditional techniques of building with earth in order to adapt them to today’s projecting needs. Examples of such techniques are unfired earth bricks and rammed earth. In order to disclosure and highlight future possibilities of earth construction, advantages and limitations of earth construction in a contemporary Western-European context are reviewed, based on a literature study. Because it is hard to generalise due to the case-specific context and constraints, a case study analysis of earth utilization in two contemporary architectural projects is presented. To assess if these contemporary projects meet the environmental benefits associated with traditional earth construction, several environmental aspects are taken into account, such as material sourcing proximity, production process, reuse potential, etc. Based on the literature study, case study analysis and current evolutions in neighbouring countries, promising applications for future development of earth construction for low impact building in Belgium are highlighted.

Whole timber construction: A state of the art review

Abstract Forests worldwide are overstocked with small-diameter trees, putting them at increased risk of disease, insect attack, and destructive high-intensity wildfires. This overstocking is caused primarily by the low market value of these small-diameter trees, which are generally unsuitable for sawn timber production and yield low prices when sold for biomass fuel, paper, or fibre-based engineered timber products. Considerable research in recent decades has demonstrated the potential for these small-diameter trees to be used in minimally processed round segments as structural elements in buildings, bridges, towers, and other infrastructure. Recent structures have also demonstrated the use of trees with major curvature and branching, which are also of low market value, in their round form as primary structural elements. Such “whole timber” construction serves as a low-cost, low-impact building system while providing revenue to forest owners to conduct harvests of low-value trees as required for sustainable forest management. This paper reviews developments in whole timber construction, presenting new non-destructive evaluation techniques, digital survey, design and fabrication methods, new processing technologies, and a diverse range of novel connection types and structural systems. It is shown that the key materials characterisation, processing, and design challenges for whole timber construction have been largely addressed, and that whole timber has the potential to be an important complement to other timber products in construction globally in the coming decades. It is recommended that future work focus on exploiting new digital technologies and scaling whole timber structural applications through increased prefabrication.

WiFi‐based passive sensing system for human presence and activity event classification

Detection of human presence and activity event classification are of importance to a variety of context-awareness applications such as e-Healthcare, security, and low impact building. However, existing radio frequency identification tags, wearables, and passive infrared approaches require the user to carry dedicated electronic devices that suffer from problems of low detection accuracy and false alarms. This study proposes a novel system for non-invasive human sensing by analysing the Doppler information contained in the human reflections of WiFi signal. Doppler information is insensitive to stationary objects, thus there is no need for any scenario-specific calibration which makes it ideal for human sensing. We also introduce the time-frequency domain feature vectors of WiFi Doppler information for the support vector machine classifier towards activity event recognition. The proposed methodology is evaluated on a software defined radio system together with the experiment of five different events. The results indicate that the proposed system is sufficient for indoor context awareness, with 95.3% overall accuracy for event classification and 93.3% accuracy for human presence detection, which outperforms the traditional received signal strength approach where accuracy is 69.3% for event classification and 83.3% for human presence detection.

A new methodology to identify and quantify material resource at a large scale for earth construction – Application to cob in Brittany

A new methodology based on the cross-referencing of spatialized pedological and heritage data is proposed to identify and quantify soil resources available for earth construction. The paper underlines the pedological particularities of areas containing earth heritage and uses these particularities to propose criteria to assess the suitability of soils for modern earth construction. The methodology applied at the regional scale in France (for a given area of 27,200 km2 in Brittany) enabled to specify five new texture classes (balance between clay, silt, sand and gravel content) of suitability for cob soils. This result calls into question recommendations available in the literature.The methodology also provides data on the scale of availability of the resource to repair earth built heritage (cob) or to build new low impact buildings with integrated modern cob walls. In the studied area the potential waste recovery of 2.8 Mt per year is measured, highlighting the large availability of materials for earth construction. At least 23% of earthwork wastes of Brittany are suitable for earth construction (0.7 Mt). However, earth remains a non-renewable material and this resource has to be properly managed, requiring an appropriate building design and maintenance in order to increase longevity and to avoid the use of admixture, preventing earth reversibility at end of life.

Construction Time of Three Wall Types Made of Locally Sourced Materials: A Comparative Study

Similarly to any other industry, the construction sector puts emphasis on innovativeness, unconventional thinking, and alternative ideas. At present, when sustainable development, ecology, and awareness of people’s impact on the environment grow in importance, low impact buildings can become an innovative alternative construction technology for the highly industrialized construction sector. The paper presents a comparative study of three walls made of available materials used locally, which can be classified as biosourced materials, in terms of construction time. The comparison of times necessary to make 1 m2 of the wall allows us to decide which building technology is more advantageous in terms of the construction duration. A shorter construction time means lower labour costs and lower expenses for construction machines. In order to obtain answers to the questions posed, the authors made extensive searches of source data on the time‐consuming building works which used locally sourced materials. Reference is made to “Temporary principles of erecting clay buildings” issued by the Institute of Housing Construction in Warsaw (Poland). Three types of walls made of locally sourced materials were studied: a wall made of clay blocks insulated with mineral wool boards, a wall made of clay compacted in formwork, and one insulated with mineral wool boards and wooden frame structure filled with straw bales and cladded with fibreboards. The layers have been chosen in such a manner that heat transfer coefficient values for the studied variants are as equal as possible (0.2 W/m2 K), thus allowing a reliable comparative study.

How the Starting Precursor Influences the Properties of Polycrystalline CuInGaSe2 Thin Films Prepared by Sputtering and Selenization

Cu(In,Ga)Se2 (CIGS)/CdS thin-film solar cells have reached, at laboratory scale, an efficiency higher than 22.3%, which is one of the highest efficiencies ever obtained for thin-film solar cells. The research focus has now shifted onto fabrication processes, which have to be easily scalable at an industrial level. For this reason, a process is highlighted here which uses only the sputtering technique for both the absorber preparation and the deposition of all the other materials that make up the cell. Particular emphasis is placed on the comparison between different precursors obtained with either In2Se3 and Ga2Se3 or InSe and GaSe as starting materials. In both cases, the precursor does not require any heat treatment, and it is immediately ready to be selenized. The selenization is performed in a pure-selenium atmosphere and only lasts a few minutes at a temperature of about 803 K. Energy conversion efficiencies in the range of 15%–16% are reproducibly obtained on soda-lime glass (SLG) substrates. Similar results are achieved if commercial ceramic tiles are used as a substrate instead of glass. This result is especially useful for the so-called building integrated photovoltaic. Cu(In,Ga)Se2-based solar cells grown directly on ceramic tiles are ideal for the fabrication of ventilated façades in low impact buildings.

Eutopia urbana vs Smart City

La rigenerazione urbana va affrontata attraverso un approccio metodologico, interdisciplinare e radicato nei territori. Si propongono pertanto azioni progettuali mirate, basate sull'uso di sistemi costruttivi reversibili, low tech, a basso impatto. Le procedure "integrate" mirano a una "manutenzione adattiva" (a carattere: "preventivo", e "correttivo") capace di "aggiornare" i manufatti architettonici per ripristinare uno standard tipologico e prestazionale elevato, qualitativamente superiore.

Exploration of building adaptations and retrofitting challenges in Ghana

Purpose – The Ghanaian banking industry has over the last 20 years witnessed tremendous growth to the extent that rural banks are now expanding their activities into urban centres. Hitherto, rural banks operated in rural and peri-urban areas in Ghana, but nowadays, there is an upsurge of rural banks activities in the urban centres of Ghana; and, they operate from rented premises, most of which are existing buildings in the urban areas. To meet the banking demands and the urban banking competitions such as the introduction of new technologies and regulations, the rural banks endeavour to expand (refurbish) the old/existing buildings with inherent adaptation and retrofitting challenges. Even though, adaptation and retrofit projects may not be popular in Ghana at large scales, this paper through combined methodology of constructive dialogue, case studies and condition survey approaches presents rural banks projects in Ghana as case studies of refurbishment and maintenance to “unearth” and resonate some key challenges of managing adaptation and retrofits in Ghana for future effective projects management solutions during their conception and execution. The paper aims to discuss these issues. Design/methodology/approach – Through combined methodology of constructive dialogue, case studies and condition survey approaches this paper presents rural banks projects in Ghana as case studies of refurbishment and maintenance to “unearth” and resonate some key challenges of adaptation and retrofit projects. Findings – The condition survey revealed unprecedented infrastructural drive by rural banks throughout Ghana and their desire to penetrate the urban areas as well. However, this drive unfortunately as it appeared, is not informed and carried out within the confines and dictates of existing legislations in Ghana. Again, it was found that adaptations and retrofitting will improve and integrate the rural banks in the urban economy through prudent project management practices. Research limitations/implications – Availability of local researches and literature on adaptations and retrofitting as project management practices in Ghana. Practical implications – Retrofitting and adaptation projects in Ghana is crucial for project management practices on low-impact building as Ghana faces energy challenges. Social implications – This research brings to bear realistic programme to build capacity of personnel to strategically integrate the rural banks into the central banking system of Ghana as well as project management practices through better and effective monitoring for social, ethical and equity impacts of their project managers. Originality/value – Apparently, adaptation and retrofit projects are not be popular in Ghana at large scales and this is the first time an academic paper of a kind has been written to guide and manage future adaptation and retrofit projects during their conception and execution as well as project management practices in general.

Wall house

Wall House is situated outside the planned city limits of Auroville, in Auromodele, an area designated for research and experimentation. The architect’s residence, it compactly accommodated everyday needs whilst effortlessly expanding to absorb guests. It attempted to not only redefine the building program for a private-residence; it tested various spatial and technological innovations to inform other projects.
 Wall House was the culmination of an ongoing extensive research and experimentation in low-impact building technologies that are environmentally and socio-economically beneficial, bynegotiating the balance between hi-tech and low-tech and incorporating everyday materials through techniques that include the participation of those with lower skills and education with few skilled craftsmen.

Riqualificazione energetica e bioedilizia in Italia: lo stato dell'arte

Building sustainability, in term of energy efficiency, low-impact building materials, renewable energy, has experienced significant growth during the past years. In response to the growing dependence on fossil fuels and importations, due in part to the increase of energy consumption in the residential sector (in 2009 46,9 Mtep, 3% more than 2008) and the recent European directives (i.e. EU 2009/28/CE) requiring CO2 emissions cut of up to 13% in 2020, there is interest in promoting energy efficiency and renewable energy technologies, which are suitable for residential applications. In this paper we present an overview on actions related to minimization of buildings energy consumption in Italy. Prevalent line of action is to improve the energy performances of building envelope (Dlgs 192/05) using insulated frames, walls and roofs and replacing heat generators with condensing boilers. In addition to national directives, ONRE Report 2011 (National Observatory on building regulations) shows that 831 Municipalities (10% more than 2010) establish mandatory targets for insulation, photovoltaic solar panels, solar water heaters, heat pumps use, correct buildings orientation, saving of water resource and local materials use. In addiction an efficient energy rating of the buildings could promote the spread of energy efficiency measurement and consequently facilitate their implementation. The new energy rating system should meet international standards, regarding environment and energy aspects, and respect territorial needs.

Breathable Walls — Sustainable Innovation for Future Built Environment

I won a major project just before I left BRE (Building Research Establishment, UK) in November 2008. The project was accepted for funding by the Technology Strategy Board (TSB) in the UK. The Technology Strategy Board is an executive non-departmental public body, established by the UK Government in 2007 and sponsored by the Department for Business, Innovation and Skills (formerly Department of Trade and Industry, DTI). The Technology Strategy Board is about supporting innovation, to stimulate technology-enabled innovation to help stimulate UK growth and productivity by removing barriers to innovation and accelerate the exploitation of new technologies. The project was to be funded under the technology priority: Components and Materials for Low Impact Buildings, which was intended to help development of innovative materials and components to be integrated into buildings to achieve the government’s target for zero carbon housing for new build by 2016. The proposed project would involve a development of a range of novel walling products manufactured using bioresin made from waste vegetable oils and natural fibres such as hemp and flax. Gypsum plasterboard was also included in the project proposal. The innovative biocomposite products would be ‘‘breathable’’ and have high thermal and acoustic properties. The materials should remove pollutants and moderate the humidity in the infiltrating air. These pollutants could be generated outdoors e.g. nitrogen dioxide, polyaromatics and particulates from traffic or be released indoors (e.g. VOCs and formaldehyde from building products). The products would be prefabricated to allow a high degree of airtightness in the construction of homes, but the breathable walls would allow sufficient air permeation and pollutants removal to ensure a low impact on the health and wellbeing of occupants. The products should contribute to a high rating required by the Code for Sustainable Homes [1]. The project required a participation of industrial partners, who are world leaders in design, production and distribution of construction products for the building industry. The production of the innovative product would fit well with the industrial partners’ business strategy for product development that would contribute to low impact, low carbon emission and energy efficient buildings. However, due to the novelty of the products, this would represent a considerable risk to the industrial company but the funding by TSB would alleviate this risk to make the project worthwhile and would contribute to the design of buildings that have ‘‘health and wellbeing’’ as the central core of consideration. Also considering the downturn situation being experienced by the construction industry, the knowledge transfer and spill-over would be an important add-on value to the project had it been funded by TSB. Indoor Air Quality and health and wellbeing were not part of the central business objectives of BRE; therefore the Environmental Consultancy and Indoor Air Quality Team was disbanded and I left BRE, the day before the announcement of funding by TSB. The project was abandoned. As there will not be future opportunity for me to work on this project, I would like to share the idea with you, maybe one day we can have innovative breathable walling products developed and incorporated into housings to contribute to the sustainable development