In dit artikel trekken wij lessen uit de opzet en contractuele en relationele sturing van een integrale gebiedstransformatie. We onderzochten of en hoe er bij de aanpak van een dergelijke grote maatschappelijke uitdaging (‘grand challenge’) in de gebouwde omgeving rekening gehouden wordt met complexiteit en onzekerheid. Ons onderzoek toont het belang aan van een integrale programmatische aanpak, waarin verschillende beleidsvraagstukken, actoren en middelen worden samengebracht om gemeenschappelijke doelstellingen te behalen. Om meer waardecreatie te realiseren moet de aanpak de complexiteit van de opgave onderkennen. Daarvoor zijn gezamenlijke visievorming tussen partners, aandacht voor verschillende waarden en belangen, en overkoepelende sturing op deelinspanningen noodzakelijk. Onder financiële druk kan gemakkelijk de behoefte ontstaan om complexiteit te reduceren, en meer controle en beheersing te introduceren door te focussen op individuele deelprojecten via strikt contractuele sturing. Dat dient echter het gezamenlijke doel niet. Naast contractuele sturing is voor succes relationele flexibiliteit nodig om onzekere omstandigheden in de toekomst het hoofd te kunnen bieden. Publieke opdrachtgevers moeten meer aandacht hebben voor sturing op samenhang en integraliteit, het onderlinge vertrouwen tussen partners, het gezamenlijk oplossen van problemen en conflictmanagement.@en

Nieuwe maatschappelijke vraagstukken als energie, circulariteit, klimaatadaptatie en hitte, leiden in de bouw tot behoefte aan eenduidige definities en afspraken over criteria en meet- en bepalingsmethoden, en ook prestatieniveaus. Welk niveau is wettelijk voorgeschreven, niet voorgeschreven maar wel haalbaar zonder weinig moeite, en aan welk niveau moeten we denken in de nabije toekomst? Denk bijvoorbeeld aan nul-energiewoningen, circulaire woningen, herbruikbaarheid bouwdelen na demontage, inzet van 100% emissieloos materieel, enz.@en

The implementation of prefabricated housing (PH) has become prevalent in China recently due to its advantages in enhancing production and energy-saving efficiency within the construction system. However, stakeholders may not always fully realize the benefits of adopting PH due to the emergence of transaction costs (TCs) in the development process of such projects. This study investigated the strategies for developers to make rational choices for minimizing the TCs of the PH project considering their own attributes and external constraints. A Bayesian Belief Network model was applied as the analytical method, based on surveys conducted in China. A single sensitivity analysis indicated that developers influence the TCs of PH through the following three most impactful factors: prefabrication rate, PH experience, and contract payment method. Integrated strategies are recommended for developers in various situations based on a multiple sensitivity analysis. Developers facing challenges due to high prefabrication rates are advised to reduce the risks by procuring highly qualified general contractors and adopting unit-price contracts. For developers with limited PH experience, adopting the Engineering–Procurement–Construction procurement method is the most efficient way to reduce their TCs in the context of China’s PH market. This study contributes to the current body of knowledge concerning the effect of traders’ attributes and choices on TCs, expanding the application of TC theory and fulfilling the study on the determinants of TCs in construction management.@en

In North-West European countries, the uptake of reusing construction elements following their first use in a building is still low. Although a large number of elements are technically reusable, they end up being recycled by crushing ormelting, or simply disposed of. This results in a high environmental impact and a net loss of economic value. This study aims to define a framework that can guide project managers, public and local authorities, as well as other organisations in setting, measuring, and reporting rates of material reuse in construction and renovation projects. To support this, a retrospective analysis was conducted on 32 construction and renovation projects that have incorporated reclaimed elements. To quantify the effective reuse rates, the data are categorised according to the types of work, functional layers, and type of projects. In summary, achievable reused targets can be determined for the structural layer (1–5% in mass), skin layer 5–15 % in mass), space plan layer (10–25 % in mass), and for outdoor surfaces (0–50 % in mass). Results confirm the contextual nature of reuse practices, emphasising that the achieved rates of reuse are linked to project types in specific layers, and depend on the overall quantity of materials in a project. It also underscores the importance of integrating reuse rate calculations proactively at the beginning of the project, particularly during the preparation of the bill of quantities. This can be accomplished by utilising appropriate procurement strategies, as-built documentation, monitoring material flows during works, and establishing a detailed record of reclaimed building elements.@en

It is recommended to integrate specific management competencies in academic education to support the transition towards environmentally sustainable practices, particularly in the construction and real estate sector. This paper explores how architectural management education can integrate environmental sustainability within its current university programmes. In recent years TU Delft explored and experimented with various education initiatives to bring forward environmental sustainability knowledge and to connect with policy, societal and industry practices. This paper describes what we learned from both bottom-up and top-down initiatives implementing environmental sustainability in construction and real estate management education. Bottom-up educational initiatives show that knowledge about transition policies, stakeholder experiences, business models and management practices from a European perspective can help students across the globe to apply knowledge into their local context, reflecting on the overarching management principals across stakeholders, institutions, academic disciplines and cultures. Top-down initiatives show that the university has a vision on integrating sustainability in its curriculum, but that integrating environmental sustainability in construction and real estate management education is still challenging. Adapting the academic curriculum to integrate building and portfolio responses to environmental challenges might be a way forward and the experiences from numerous elective courses and educational initiatives can be a basis to identify the development of a future standard curriculum.@en

Vijf woningcorporaties in de regio Haaglanden gaan een langdurig partnerschap aan met enkele vaste aannemers: Vidomes, De Goede Woning, Rondom Wonen, Stedelink en Rijswijk Wonen. Dit initiatief - Bouwstroom verduurzaming genoemd - heeft tot doel om in 8 jaar tijd naar verwachting 9.000 sociale huurwoningen te renoveren en verduurzamen. Eind januari zetten de bestuurders van de betrokken corporaties hun handtekening onder de intentieovereenkomst voor deze intensieve samenwerking, waarbij alle woningen in één keer worden aanbesteed. @en

Passports for circularity, e.g., digital product passports and material passports (MPs), have gained recognition as essential policy instruments for the Circular Economy goals of the European Union. Despite the growing number of approaches, there is a lack of knowledge about the data requirements and availabilities to create MPs for existing buildings. By deploying a mixed-method research design, this study identified the potential users and their data needs within the context of European social housing organisations. Three rounds of validation interviews with a total of 38 participants were conducted to create a data template for an MP covering maintenance, renovation, and demolition stages. This data template was then tested in a case study from the Netherlands to determine critical data gaps in creating MPs, including, but not limited to the composition of materials, presence of toxic or hazardous contents, condition assessment, and reuse and recycling potential of a product. Finally, an MP framework is proposed to address these data gaps by utilising the capabilities of enabling digital technologies (e.g., artificial intelligence and scanning systems) and supportive knowledge of human actors. This framework supports further research and innovation in data provision in creating MPs to narrow, slow, close, and regenerate the loops.

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In activiteit 3 van onderzoek 7.2 is in de vorm van Webinars aandacht gegeven aan de organisatie-overstijgende initiatieven. Deze zijn ook in een bredere context geplaatst van collectief opdrachtgeverschap en inkoopsamenwerking tussen (semi-)publieke opdrachtgevers. Het was de bedoeling om fysieke seminars te organiseren, echter die zijn door de (voortdurende) Covidepidemie allemaal georganiseerd als Webinars. @en

Oorspronkelijk was IEBB project 7.2 bedoeld als ondersteuning en onderbouwing van het programma De Renovatieversneller. Dit programma richt zich op de vraag-aanbodbundeling van minimaal twee corporaties en twee aanbodpartners binnen één project: oftewel een organisatie-overstijgende aanpak van de verduurzamingsopgave. Het was dan ook de bedoeling dat de nadruk in dit onderzoek zou liggen op de analyse van deze organisatie-overstijgende verduurzamingsprojecten. Dit is later door De Renovatieversneller Collectief Professioneel Opdrachtgeverschap (CPO) genoemd. Na een eerste inventarisatie (zie paragraaf 1.2) is eind 2020 besloten om de focus van het project te verleggen. De organisatie-overstijgende aanpak komt (nog) niet of nauwelijks van de grond. De bekende organisatie-overstijgende voorbeelden en initiatieven die er zijn, kregen daarnaast al veel (onderzoeks)aandacht. In de eerste plaats van de partijen die bij De Renovatieversneller betrokken zijn. Daarnaast had RVO/De Renovatieversneller Brink opdracht gegeven om begin 2021 de bestaande initiatieven nader te belichten (zie https://derenovatieversneller.nl/leerplaats). Medio 2021 is overigens besloten om tijdelijk met de Renovatieversneller te stoppen, vanwege een gebrek aan succes. Van de vier initiatieven die begin november 2020 waren ingediend, was er een te laat met de inschrijving en aanmelding. De overige drie initiatieven voldeden niet aan de voorwaarden en werden afgewezen. Wel ondersteunt De Renovatieversneller enkele initiatieven met processubsidies. Het is de bedoeling dat er een doorstart wordt gemaakt met de Renovatieversneller in 2022. De ervaringen met de eerste regeling en de geleerde lessen worden gebruikt om te komen tot een aangepaste regeling. Uit de eerste inventarisatie van voorliggend onderzoek blijkt dat er veel interessante initiatieven zijn van individuele corporaties die samen met één of meer aanbieders (aanbodketens) het onderhoud en de duurzame verbetering van hun bezit project-overstijgend aanpakken. Deze corporaties blijken vooral behoefte te hebben aan een integrale verduurzamingsaanpak van hun bezit en niet zozeer op het in engere zin energetisch verbeteren van bepaalde woningtypologieën (waarop de nadruk ligt in de Renovatieversneller). Dit onderzoek richt zich op deze project-overstijgende ontwikkelingen en initiatieven. Voordat nader ingegaan wordt op de probleemstelling en de aanpak van deze project-overstijgende initiatieven, een kort overzicht van de resultaten van de eerste inventarisatie.@en

In the last decades, considerable work has been done regarding service life prediction of buildings and building components. Academics and members of the CIB W080 commission, as well as of ISO TC 59/SC14, have made several efforts in this area and created a general terminology for the concept of service life, which is extremely relevant for property management, life cycle assessment (LCA) and life cycle costs (LCC) analyses. Various definitions can be found in the literature that share common ideas. In fact, there are different criteria that trigger the end of a building’s service life, but the trap that building practitioners too often fall into and that should be avoided is dividing a problem into separate boxes, labels, and specializations without the mutual cohesion and interaction, and ignoring human behavior. Some definitions of service life are discussed in this review paper, in which the cause-effect processes underlying aging and decay are described. These descriptions highlight the continuous interrelation between different criteria for the end of a building’s service life, considering too often neglected and misunderstood causes of the end of life. @en

Dutch policies to reach a CO2 neutral housing stock in 2050 force housing associations to realise higher renovation rates at lower costs. The potential for standardisation in renovation processes of the housing stock is huge. Practice shows that an increasing number of housing associations bundle their individual maintenance and sustainable renovation projects in renovation programs for two or more years. Programs that are then implemented in strategic partnerships with maintenance contractors. This paper clarifies the rationale behind this development, sketches internal and external factors that encourage and hinder this development and presents the effects of the shift from projects to programs. The paper contributes to the scientific body of knowledge of public clients in construction collaborating with market parties. The research provides housing associations and contractors tools for the implementation of successful partnerships. The paper is based on an explorative literature review and case-studies of strategic partnerships in this field. The findings show that strategic partnering in housing renovation programs increases the renovation rates of individual housing associations. Also the tenants' satisfaction with the renovation process is high. Trust is key in the collaboration between the strategic partners. Hindering factors are the realisation of the necessary culture and organizational changes on both the supply and demand side.

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The world is facing an alarming housing crisis. The challenge for the construction industry is to find sustainable ways to meet this growing housing demand. The concept of Circular Economy could be an alternative approach as it aims to regenerate, narrow, slow, and close resources loops. Digital technologies are seen as enablers to implementing these looping strategies through their capabilities for managing information and supporting collaboration and new business model creation. In the built environment, many digital innovations have emerged that support the circular transition of the industry at various spatial scales. However, these innovations mainly focus on nano, micro, and macro scales and lack perspectives on the meso level (real estate portfolio). This research aims to understand how digital technologies can support circular strategies at the meso level by collecting empirical evidence from the European social housing organizations actively experimenting with circular strategies. We conducted a multiple-case study method and chose two cases from the UK and Belgium. We collected data through desk research and online group interviews. Our results indicate that housing organizations adopt a wide range of circular strategies for managing their housing portfolio. The support of digital technologies to perform the circularity is low. Our findings suggest five potentially enabling digital technologies at the meso level supporting the housing sector towards circularity: circular asset management tools, digital building logbooks, material passports, BIM, and collaboration tools.@en

Digital technologies are considered enablers of circular economy implementation in the built environment. Literature mainly focuses on conceptual or review studies examining the role of digital tools (e.g., material passport and building information modelling) to close the material loops. There is a lack of understanding of how digital technologies are implemented in real-life and whether they offer value to the industry actors. This study conducted a multiple-case study to collect empirical evidence from Dutch social housing organizations actively applying circular principles in new construction, renovation, maintenance, and demolition projects. Our findings suggest that artificial intelligence, digital twins, and scanning technologies support data collection, integration, and analysis for slowing the loops strategies (i.e., maintenance), while digital marketplaces facilitate material reuse, enabling narrowing and closing the loops. This study identified 12 challenges that hinder the broader adoption of digital technologies that are associated with the technological, cultural, market, and regulatory factors.@en

Steeds meer woningcorporaties werken project-overstijgend samen met marktpartijen bij de verduurzaming van hun woningen. Onderzoek van de Tu Delft laat zien dat deze samenwerking voor de corporaties, hun bewoners en de ketenpartners voordelig is. Het samenwerken stelt wel forse eisen aan de organisatie, het beleid en de taken en rollen van corporaties en partners. Dit artikel geeft een beeld van de algemene ervaringen bij "koplopers". Om te illustreren dat er geen blauwdruk is voor project-overstijgend samenwerken, belichten we twee voorbeelden uitgebreider: de Alliantie en ZOwonen.@en

Purpose: The recent promotion of prefabricated housing (PH) in China has resulted in a prosperous period for its implementation. However, transaction costs (TCs) cause low economic efficiency to stakeholders and hinder the further promotion of PH. No relevant study has yet been made to investigate the TCs and their causes in the PH field. This paper identifies critical TCs and explores the influencing factors from the developers' perspective. Design/methodology/approach: Semi-structured interviews and a questionnaire survey were used to collect data about TCs and influencing factors. The most influential factors are identified with their impacts on particular TCs, yielded from correlation analysis and logistic regression. Findings: From the developers' perspective in China's PH market, this study identified that the most concerning sources of TCs are: hidden costs arising from disputes, extra workloads from design changes, learning costs, intensive communication and coordination in assembly and unexpected information costs in decision-making. The use of an ordered logistic regression approach indicates that the four most influential factors are: qualification of the general contractor, mandatory local policies, owner type and competitiveness of the developer. Practical implications: To reduce the TCs, experiencing learning and ensuring the design scheme's complicity are recommended to save information searching and exchanging costs. The implications for the PH developers are for them to: (1) professionalize their own organization and (2) procure high-qualified general contractors. For the policymakers, this means they should improve the clarity of the mandatory local policies for PH step-by-step. Originality/value: By applying the TCs economic theory, this study explores factors that influence TCs in the PH industry. It sheds light on the influencing mechanism behind the TCs in the context of prefabricated housing.

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