News

January 31, 2024
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Toni Tuomola, District Manager, Skanska (Finland)

Skanska’s role in ReCreate is strongly linked to its goal of building a better society. Being climate-smart – one of our sustainability themes – supports the achievement of this goal. Within the ReCreate project, we are studying how to produce low-carbon solutions through our business operations. ReCreate will provide us with information on how the circular economy of building elements could be promoted in the future – for example, in the planning phases of construction projects. We can have a major influence over the carbon footprint of a project’s outcome, especially in in-house development projects and, above all, in projects where we are responsible for the design.

ReCreate’s Finnish deconstruction pilot site is a 1980s office building in the city of Tampere. The precast concrete frame has been dismantled using a new technique developed and studied as part of the project. Construction projects are complex entities that demand close cooperation to meet targets. We have already worked with the ReCreate project partners for a couple of years on studies and advance preparations to facilitate the practical deconstruction work. Thanks to the studies, we were capable of dismantling the precast concrete elements intact for reuse. We also know how to verify the properties of reusable elements reliably and cost-effectively.

The possibility of technical implementation alone is not enough

 

Creating a business ecosystem for reusing building elements is an important part of the project. Reuse requires off-site production plants for factory refurbishment and the creation of an entire logistics chain and information management process to put the elements to use again. A marketplace is also needed to bring product providers and users together. Barriers must be lowered in building regulations and practices, and operating models must be harmonized.

What are the implications if reuse is successful? Firstly, the environmental benefits will be significant because the carbon footprint of reused concrete elements is about 95% smaller than that of corresponding new elements. Therefore, it will be possible to realize a substantial decrease in the carbon footprint of new buildings. Reused elements may not necessarily be used to construct entire buildings, but they would be utilized in the most suitable places. This would ensure that the dimensional and strength properties of reused elements can be used to the best effect.

The reduction in the carbon footprint helps us to meet the low-carbon requirements that will be introduced through regulation in the future. Environmental certification programs such as LEED and BREEAM also award extra points for reusing building materials.

Decommissioning a building by deconstructing elements is slower and more expensive than conventional destructive demolition. However, prior international research has found that a reused element can be as little as 30% of the price of a new element. This is an important perspective for projects researching business opportunities based on the circular economy.

A climate-neutral society is the sum of many parts, large and small. The circular economy of precast concrete elements is one factor among many. We need all the parts to work together to reach this goal.


December 13, 2023
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Christoph Henschel, BTU

In conventional architectural projects, the use of the building and the design concept typically determine the dimensions of the structure. This means that the height of spaces, as well as the width and length of rooms, are defined by what will happen in them once they are built. Constraints on the size of a building are usually only imposed by limited budgets, the site and its context, or zoning laws. All of this changes drastically when reused precast concrete comes into play. Suddenly, the structure dictates the spatial dimensions, the grid size or the floor heights of the building design. This changes the design task for the architect and presents new challenges. In order to show that these challenges are also full of opportunities, the following text describes the design process for the German pilot project within the ReCreate project, a youth center for the town of Hohenmölsen.

The design task began with a detailed analysis of the elements that could be salvaged from the donor building. Specific types, dimensions and available quantities of exterior and interior walls and ceiling slabs were determined. Preliminary tests of the concrete strength and examination of the reinforcement properties ensured the suitability for reuse in advance. With this catalogue of elements as a starting point, the design process for the new building could begin – always with the goal of using as many reused elements and as little new material as possible.

Resource: BTU Cottbus Senftenberg

The mayor of Hohenmölsen drew up a rough room plan that served as the basis for the initial design. It included a multi-purpose room, a kitchen and dining hall, several smaller rooms for offices or after-school use, and some additional rooms such as restrooms, storage, and a technical room. With these requirements in mind, an initial building layout sketch was created with the goal of locating the various uses in customizable areas of the future building. Conditions such as the distance from the entrance, the proximity of certain rooms to each other, or the orientation to the east, west, or south to ensure the best lighting were taken into account.

This initial sketch was then superimposed on a grid of 2.4m by 3.6m – the maximum length of the ceiling slabs in the donor building. After a few attempts and several iterations of rotating certain rows in the grid by 90°, two initial building designs were created and presented to the town of Hohenmölsen.

Resource: BTU Cottbus Senftenberg

A special design decision was to use the former exterior walls not only as exterior walls but also as interior walls in the new building to show that the building was created from reused elements. This also allowed for interior windows between two rooms, which was an interesting way to visually connect separate rooms.

Resource: BTU Cottbus Senftenberg

The two initial building designs were presented by BTU at the town hall of Hohenmölsen and then discussed by the mayor with the town representatives. As a result of this discussion, BTU was asked to make a number of changes to the design in terms of size and use. This second design phase resulted in a combination of the two previous designs into one more detailed approach. In this design, it was already apparent that for the larger spaces, such as the dining room and multi-purpose room, the 3.6m ceiling spans were not sufficient, so new beams and columns were introduced to create wider spaces with double the span, resulting in a width of 7.2m. At this point, the method of showing reused elements in black lines and new material in red on the drawings was established. This allowed for a quicker overview of where reused elements would be located.

Resource: BTU Cottbus Senftenberg

During this design phase, the concept of multiple entrances to the building was developed, so that there is not just one main entrance, but several ways to approach the building, which can activate the building’s surroundings much better.

After another round of feedback from the town of Hohenmölsen, some minor changes were made and terrace roofs were added to the design. In this design, it is now possible to enter and exit the building from all four sides. This allows users to access the site from all sides. In this design, 47 used exterior walls, 7 used interior walls and 56 ceiling slabs are used.

Resource: BTU Cottbus Senftenberg

Some time passed and the town of Hohenmölsen contacted BTU again, stating that the original space plan was not sufficient and that more space was needed. With the experience from the previous designs, a new layout was developed. The new design introduced the idea of a functional block with all building services such as kitchen, toilets, storage, etc., to be placed in the center of the building. This allows all the other rooms where youth activities or office work will take place to receive natural light.

Resource: BTU Cottbus Senftenberg

The downside of this design was that it had a huge footprint of almost 700 m2 due to the increased space requirements. This led to the idea of arranging the spaces on two levels, creating a two-story building. The previous spatial configuration of a service core with a surrounding corridor and entrances on all four sides of the site was retained. Due to the peculiarities of the reused concrete elements and the limited grid size, it was decided that the upper floor would be accessed only by an exterior staircase to simplify the construction and avoid potential fire safety concerns.

Resource: BTU Cottbus Senftenberg

In this final design, 35 exterior walls, 25 interior walls and 103 floor slabs from the donor building will be reused, resulting in a net floor area of 505 m2 on the ground floor and 263 m2 on the upper floor. The new structural elements are initially planned to be new precast concrete elements such as columns and beams. New exterior and interior walls will be made of wood stud walls and ecological insulation such as wood fiber boards. For the facade, the reused exterior walls can be insulated with only 6 cm of wood fiber boards due to the low density concrete they are made of, while the reused interior walls, which will be positioned as new exterior walls, will require 14 cm of insulation. The façade will be a ventilated cladding of reused wood panels and reused corrugated metal, installed as available.

All in all, the design process was challenging, but also interestingly unusual, because the building elements determined many decisions that would otherwise have to be made by the architect or the client. Introducing new elements and rotating the grid in certain places allowed for some flexibility and gave just enough freedom to realize all the required uses in the building. The German ReCreate country cluster hopes to start construction of the youth center in late 2024 or early 2025.

Resource: BTU Cottbus Senftenberg


December 8, 2023
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Ahmad Alnajjar, PhD student at KTH

ReCreate project is a forward-thinking initiative that explores the reuse of precast concrete elements from various angles. A key aspect of this project is evaluating the climate benefits from a life cycle perspective. Our recent work, particularly in the Swedish pilot construction, has shown promising results in reducing embodied carbon – a crucial step in sustainable and circular building practices. About 92% of embodied carbon was avoided at the building level which is largely attributed to the reuse of concrete elements, including precast concrete elements. This achievement aligns with previous research highlighting the benefits of reusing precast concrete and further emphasizes the reuse’s effectiveness in mitigating the environmental impact of construction. Unlike most previous studies, the embodied carbon evaluation of the Swedish ReCreate pilot project stands closer to real-world applicability. It is based on field experiments conducted by seasoned professionals in the building sector, adding practical validity and depth to our findings.

An important facet of our findings in the ReCreate project underscores a significant advantage in the reuse of whole precast concrete elements over traditional recycling methods. Through our comprehensive analysis, it has become evident that the embodied carbon savings achieved by reusing entire elements are considerably greater than those realized by merely crushing to recycled concrete aggregate and shredding the rebar to steel scrap. This distinction is crucial, as it highlights the substantial environmental benefits of reusing structures in their complete form. By opting for reuse over recycling, we not only retain the material’s inherent value but also significantly reduce the carbon footprint associated with the production of new building materials.

Our assessment has also brought to light interesting insights. Contrary to common concerns, we found for example that the transportation of reused elements does not significantly add to the project’s carbon footprint, as it is comparable to the transport distances of new building materials. We hope that this finding will encourage building industry actors to reconsider their material sourcing strategies, recognizing that incorporating reused elements can be both environmentally beneficial and logistically viable.

Currently, our team is focused on comprehensively understanding the future availability and demand for pre-used precast concrete elements. We are assessing both the timing of their availability and the quantities that can be effectively reused in new construction projects. By addressing these critical aspects, we aim to elucidate the role that reusing precast concrete elements can play in meeting Sweden’s and the EU’s ambitious climate goals.

Through the ReCreate project, we are exploring new avenues in construction, aiming to make a meaningful contribution to sustainable building practices. Our team is dedicated to not only implementing these innovative practices but also to rigorously documenting and analyzing our findings. Our research will soon be available in various scientific journals, providing a detailed and scholarly overview of our work and its implications for sustainable construction. Keep an eye on our progress as we delve further to uncover the potential and challenges of this innovative approach and look out for our publications to gain a deeper understanding of the impact and scope of our project.


November 13, 2023
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Matias Rokio, Tampere University – 13 November 2023

My name is Matias Rokio, and for the year 2023, I’ve been doing research in ReCreate. My background is in industrial engineering and management, and I have been studying since 2017 at Tampere University. I graduated with an M.Sc in June 2023 and wrote my Master’s thesis on resilience in Finnish health care with an emphasis on information asymmetries. My minor in sustainable production steered me towards the areas of sustainability and circular economy, which I feel should receive a lot of attention in research in varied fields. Currently, I am in the process of applying for a doctoral position at Tampere University, which I will hopefully receive sometime during this year. In my personal life, along with my work as a researcher, I am a semi-professional drummer in a few different groups and doing all kinds of session work for different artists.

Currently, I am working at Tampere University in a CROPS research group, which collaborates with ReCreate’s WP7 through my research. According to WP7 objectives, the work package aims to accelerate the development of a scalable and profitable business model for reused precast concrete components in different environments. Especially within the construction industry, the circular economy has tremendous potential in driving a transition towards more sustainable practises, as concrete manufacturing alone generates around 4-8% of the world’s CO2 emissions.

My research article on ReCreate approaches the concrete element reuse from project management’s perspective, with an aim to unveil how applying circular economy principles in projects affects the inter-organisational collaboration and value creation in the project front-end. In my research, the front-end spans the planning phase of the Finnish country pilot, where the deconstruction of an office building in Tampere city centre and the subsequent phases to it were planned in detail. The purpose of the research is to enrich the discussion around sustainable project management and showcase a project where sustainability is promoted through circular economy practises. Also, the circular economy discussion, despite its trending and important nature, is currently still lacking in the project management context, which makes the research interesting for project management scholars.

In the research, we found out that when a construction project is based on the reuse principle, the front-end phase requires more actors to collaborate in the project planning and some actors are required to take on new tasks in the project. For example, a structural engineering company was an integral part of the deconstruction planning of the building, whereas, in a conventional demolition project, the demolition company does the planning by themselves. It is also evident that there are several new business opportunities for the actors involved that could build new services and marketplaces around the reusable concrete elements and reach new customers through collaboration in the project. Currently, several barriers to the wider adoption of concrete elements reuse still remain, as manufacturing new concrete elements is relatively cheap whilst detaching, and refurbishing the old elements is somewhat time-consuming, and a regulative incentive for adopting the reuse principle is lacking.


November 10, 2023
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Viktoria Arnold, researcher at BTU Cottbus – Senftenberg, Germany

The assessment of the sustainability of buildings has been increasing rapidly in recent years. This is not only related to the international goals of the United Nations, which are set out in Agenda 2030[1] and include global ecological, economic and socio-cultural aspects in the building sector (SDG 11[2], 12[3] and 13[4]). It is also linked not only, but in large part, to the national goals of the United Nations, which each country has set for itself. Germany, for example, has set a goal of achieving greenhouse gas neutrality in its building stock by 2050[5]. Different countries have different requirement methods. Some countries have made it mandatory to submit a so-called Climate Declaration for future building during the approval phase and to comply with certain limits for greenhouse gas emissions, such as the Netherlands, Sweden and Finland. Other countries, such as Germany, subsidise climate-friendly construction and renovation measures. Some builder-owners are just interested in building sustainably and climate-friendly and want to know what design decisions, building products and materials have what impact on the environment. And what contribution the building as a whole makes to resource and climate protection during its entire life cycle. To find this out, many sustainability assessment systems for buildings are used, which have LCA (Life Cycle Assessment) as one of the most important criteria. The basis for LCA is the EPDs (Environmental Product Declarations) based on ISO 14025 and EN 15804 for the different building products and materials. The more building products and materials have an EPD, the more accurate the calculation of the environmental impact of a building. This will greatly assist the builder-owner when deciding on certain construction and architectural solutions, and what contribution the building as a whole makes to resource and climate protection throughout its complete life cycle.

I am doing my doctorate at BTU on sustainability assessment of single-family houses. For such buildings, which are nowadays a luxury from a climatic point of view, such an assessment is particularly important.

In the ReCreate project, our German Cluster is particularly responsible for work package 6 “Energy and Climate”, which aims to evaluate the environmental and economic impacts (LCA and LCC (Life Cycle Costing)) of the reuse of precast concrete elements. Our major objective is to produce one or more EPDs for the precast concrete elements (ceiling, exterior and interior wall) suitable for reuse. This will enable LCA for new buildings with the reused elements and distinguish such resource and climate-friendly projects from others. Several previous research projects led by Prof. Angelika Mettke[6] have shown that the reuse of concrete building elements can significantly reduce the carbon footprint and energy consumption in the product phase by up to 93-98% compared to new production[7].

We notice again and again in our research that reuse can only be possible if the parts are still considered in the installed condition and the careful disassembly is carried out by an experienced company in the best case. Recently, the new DIN SPEC 91484[8] has been published, which is the basis for evaluating the high-quality connection potential for building products before demolition and renovation works where Prof. Mettke has been involved. Another prerequisite for successful reuse is that the building documents are available and, if possible, up to date. This is rarely the case with existing industrially constructed buildings that are up for deconstruction. That is why today’s initiative on the building resource passport is very important, where all building materials and products used, as well as their quality and recyclability, are recorded and kept up to date. It is also important to look now at what can be used to build more sustainable buildings so that the new building can be reused later at the end of its life cycle.

I am asking all these research questions in my doctoral thesis because it is still not so far that one comes to the idea of building a single-family house from used precast concrete elements.

[1] Sustainable Development Goals

[2] SDG 11 Make cities inclusive, safe, resilient and sustainable

[3] SDG 12 Ensure sustainable consumption and production patterns

[4] SDG 13 Take urgent action to combat climate change and its impacts

[5] Deutsche Nachhaltigkeitsstrategie Weiterentwicklung 2021, p. 103

[6] Structural Recycling Unit, Faculty 2 of Environment and Natural Sciences, BTU Cottbus – Senftenberg

[7] Mettke, A. (2010). Material- und Produktrecycling – am Beispiel von Plattenbauten. Zusammenfassende Arbeit von 66 eigenen Veröffentlichungen, Cottbus, Techn. Univ., Habil.-Schr. p. 235–243

[8] DIN SPEC 91484:2023-09 “Procedures for recording building products as a basis for evaluations of connection use potential prior to demolition and renovation work.”


September 29, 2023
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In the heart of Tampere, Finland, the ReCreate project’s core group recently convened for a two-day program that combined insightful discussions, presentations, and an eye-opening site visit. Hosted by the project coordinators at Tampere University, this gathering showcased the collaborative spirit and dedication of the ReCreate consortium.

Day 1: Core Group Meeting

The first day of the event was dedicated to the ReCreate project’s core group meeting. This session served as a platform for project partners to exchange ideas, review ongoing activities, assess the status of deliverables, and chart a course for future actions within the project.

Participants came together to discuss their respective areas of work, share valuable insights, and align their efforts towards the project’s overarching goal of revolutionizing construction and deconstruction practices to achieve sustainability.

Day 2: Site Visit and Presentations

On the second day, just before embarking on a site visit, ReCreate partners held a series of brief presentations. Each presentation provided a perspective on the ongoing work in Tampere:

  1. Mr. Tero Niemelä, Skanska: Skanska, specializing in construction and project development, shared their contributions to the project, shedding light on their areas of expertise and the challenges they are tackling.
  2. Ms. Inari Weijo, Ramboll: Ramboll, engaged in technical research, and delved into their work related to structural condition surveys, deconstruction techniques, quality assurance, structural design, joint techniques, and reinstallation.
  3. Mr. Antti Lanta, Umacon: Umacon, with its role in checking elements for damage and transportation logistics, provided insight into their efforts in ensuring the efficient reuse of construction elements.

Following these presentations, participants eagerly set out on a site visit to witness the ongoing deconstruction work in a donor building. The building’s skeleton frame, consisting of columns and beams, as well as hollow core slabs as intermediate floors, is being carefully disassembled. The reclaimed elements from this building will find new life in future construction projects, aligning with ReCreate’s core mission of promoting circular construction.

The ReCreate core group meeting and site visit in Tampere showcased the power of collaboration, innovation, and sustainability in the construction industry. It’s a testament to the dedication of project partners and their commitment to shaping a more sustainable future for the industry.

Stay tuned for more updates on the ReCreate project’s journey as it continues to make waves in the world of construction and deconstruction.


September 27, 2023
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We are thrilled to announce that the ReCreate project will be featured among other EU-funded initiatives at EU Industry Days 2023, set to take place from October 4th to 6th at the FYCMA (Trade Fairs and Congress Center of Málaga) in Spain. This event promises to be a melting pot of innovation, where industry leaders, policymakers, and experts will converge to accelerate the digitalization, sustainability, and efficiency of production models in Europe.

EU Industry Days, the European Union’s flagship annual event dedicated to industry, is making its way to Málaga. It serves as a vital platform for forging connections, fostering collaborations, and driving innovation across various industrial sectors. At the heart of this event is the mission to facilitate Europe’s transition towards a more sustainable and digitally advanced industrial ecosystem.

ReCreate is an EU-funded project committed to redefining construction through the reassembly of precast concrete elements, thus contributing to circular construction practices. By examining the entire construction and demolition ecosystem, ReCreate explores systemic changes needed to maximize the reuse of precast structural components, preserving their secondary materials at their highest value.

We invite you to visit our exhibition at EU Industry Days 2023 to learn more about the ReCreate project and witness firsthand how circular construction and sustainable practices can shape the future of our industry. Join us in Málaga as we collectively work towards a more innovative, collaborative, and sustainable industrial landscape.

Don’t miss this opportunity to be part of the transformative journey in the European industrial sector. See you at FYCMA in Málaga from October 4th to 6th!


September 27, 2023
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Arlind Dervishaj, architect and doctoral researcher at KTH Royal Institute of Technology

The use of digital tools for the design of buildings has become a common practice for architects and engineers alike, commonly referred under the umbrella term digital design. The range of digital tools at our disposal and their utilization has been growing, with reference to Building Information Modelling (BIM), environmental design tools, computational design plugins, and optimization algorithms. Additionally, 3D printing, robotic fabrication, virtual reality, and Artificial Intelligence (AI) are becoming more commonplace not only in research environments but also with practical applications within the architecture and engineering fields. Despite these advancements that have made it easier to design and assess the sustainability of projects, buildings remain a major contributor to climate change, responsible for 37% of global carbon emissions, half of all extracted raw materials, and waste generation due to construction and demolition activities. In light of these challenges, the circular economy concept presents a promising solution, with digital technologies playing a crucial role as enablers.  The importance of reevaluating the relationship between design and the digital became the focus of the 41st eCAADe (Education and Research in Computer-Aided Architectural Design in Europe) conference hosted at TU Graz under the theme Digital Design Reconsidered.

At eCAADe 2023, I presented a refereed paper, with co-authors Arianna Fonsati, José Hernández Vargas, and prof. Kjartan Gudmundsson [1]. The paper is titled Modelling Precast Concrete for a Circular Economy in the Built Environment with subtitle Level of Information Need guidelines for digital design and collaboration. This was also the first presentation in the eCAADe session on BIM & Sustainability. I kicked off my presentation by captivating the audience with striking examples of AI-generated buildings crafted from reclaimed concrete elements, setting the stage for an important question to follow.

Can we design buildings with reused elements simply with a text prompt and AI or is there more to consider?

Before the design process, the practice of reuse involves a series of essential steps, which encompass, among other things, the identification of suitable buildings and components for reuse, the process of deconstruction, the management of storage, and the implementation of quality assurance measures. Reliable and up-to-date information is crucial in supporting designers and stakeholders in making decisions for circular construction. Various data capture methods for buildings exist to facilitate their identification and potential reuse. These methods encompass technologies such as laser scanning, photogrammetry, scan-to-BIM workflows, and machine learning algorithms. Examples of the latter include identifying materials and components at urban and building scales, and some even automate the creation of 3D models from point clouds.

Nevertheless, a substantial gap remains within the literature with relevance for practice concerning the specifics of required data and the process of sharing and requesting information to enable reuse and collaboration of different parties. To address this challenge, we developed a set of digital reuse guidelines tailored specifically for precast concrete. These guidelines are based on the Level of Information Need (LOIN) standard EN 17412-1:2020 [2], and are informed by our experience in the ReCreate project, which includes construction pilots conducted in Sweden (Swedish pilot at the H22 City Expo) and in partner countries. Our study not only embraces the EN 17412 standard but also takes it a step further by extending its applicability for digital reuse in circular construction. These guidelines are designed to enhance the reliability of information across the reuse process and construction cycles. They introduce innovative concepts, such as the creation of digital templates that evolve into digital twins of reused precast elements. Furthermore, they can be used for specifying information requirements for reused as well as for newly produced elements. Additionally, as part of our comprehensive approach, we have included a comparison of the geometrical modelling aspects of LOIN in two widely used CAD and BIM software platforms, Rhino and Revit.

Currently, our ongoing research within the ReCreate project continues to explore and expand upon various aspects that can relate to the LOIN framework. As an example, another recent paper authored by me, José, and Kjartan was presented at the 2023 EC3 & 40th CIB W78 conference in Crete, Greece [3]. This paper explores the timely theme of tracking and tracing building elements, where more background information can be found in the literature [4], [5]. We present a novel digital workflow for modelling various tracking tags in the BIM model such as QR codes, Radio Frequency Identification (RFID), and Bluetooth. Moreover, we present promising results from laboratory tests that, arguably for the first time, explore the utilization of Near Field Communication (NFC), which is a subset of RFID, and its integration with Bluetooth technology.

More facets on the topic of reuse are being investigated within ReCreate that will further demonstrate the applicability and potential of digital reuse in creating a circular built environment. Our research encompasses a wide spectrum of considerations, including data capture and sharing methods, material passports, destructive and non-destructive testing of concrete structures, and innovations in the design processes. These ongoing efforts aim to advance sustainability and circularity in the built environment through the integration of digital technologies.

References:

[1] A. Dervishaj, A. Fonsati, J. Hernández Vargas, and K. Gudmundsson, “Modelling Precast Concrete for a Circular Economy in the Built Environment,” in Digital Design Reconsidered – Proceedings of the 41st Conference on Education and Research in Computer Aided Architectural Design in Europe (eCAADe 2023), W. Dokonal, Hirschberg Urs, and G. Wurzer, Eds., Graz: eCAADe, TU Graz, Sep. 2023, pp. 177–186. doi: 10.52842/conf.ecaade.2023.2.177.

[2] European Committee for Standardization (CEN), “Building Information Modelling – Level of Information Need – Part 1: Concepts and principles (EN 17412-1:2020),” 2020 Accessed: May 18, 2022. [Online]. Available: https://www.sis.se/en/produkter/standardization/technical-drawings/construction-drawings/ss-en-17412-12020/

[3] A. Dervishaj, J. Hernández Vargas, and K. Gudmundsson, “Enabling reuse of prefabricated concrete components through multiple tracking technologies and digital twins,” in European Conference on Computing in Construction and the 40th International CIB W78 Conference, Heraklion: European Council on Computing in Construction, Jul. 2023, pp. 1–8. doi: 10.35490/EC3.2023.220.

[4] M. Jansen et al., “Current approaches to the digital product passport for a circular economy: an overview of projects and initiatives,” vol. 198, 2022, doi: 10.48506/OPUS-8042.

[5] European Commission, “Transition pathway for Construction.” Accessed: Mar. 17, 2023. [Online]. Available: https://ec.europa.eu/docsroom/documents/53854


September 14, 2023
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Using object-oriented programming to bridge the gap between architecture and structural engineering in a circular design.

Fred Mudge, Eindhoven University of Technology – 14 September 2023

Over the past several decades, the construction industry has been responsible for large portions of annual global CO2 emissions and overall material usage. To counteract this, the ReCreate project aims to establish a circular value chain for precast concrete buildings – a switch which could offer massive improvements to the industry’s sustainability by keeping materials in use for longer, thereby preserving the value contained in the existing building stock and reducing the need for new materials. This requires research and development across the entire reuse process, from deconstruction, transport and logistics, quality control, design and planning of new buildings up to reassembly in a new location and for a new purpose.

As a doctoral researcher at TU Eindhoven, my work focuses on the topic of design within the above context and aims to assist architects and engineers to design circular buildings, by developing a software application which provides functionality specifically for this task.

In a traditional building design workflow, the architect normally produces a design based on relatively few constraints. A structural engineer reviews the design and presents reinforcements to ensure that the structure is sufficiently robust and stable. After all designs have been finalized, construction can commence and (for precast systems) elements are manufactured that match the designs. The design process for reused elements is fundamentally different because the geometric and structural attributes of the elements are already fixed at the start of the design process. The challenge for a designer is therefore to select and arrange elements into a spatially effective building structure considering their respective geometries. Each addition or change to this arrangement affects the distribution of forces through the structure. The forces exerted on each element should therefore be calculated continuously and compared to its relevant structural capacities (axial force, bending moment etc.) to ensure no element is loaded past a safe limit.

The design application addresses both challenges mentioned above. It includes a feature for browsing through a library (database) of previously used building components that are available for reuse. A user can then select and import desired elements directly into a 3D building information modelling (BIM) environment and place them in a new design assembly. Furthermore, automatic structural load calculation methods using finite element methods (FEM) are built into the application and can be performed on-demand, to identify any elements exerted past their capacities. Lastly, environmental benefit is quantified and enhanced by automatic embodied carbon calculation, considering factors such as the distance of an element from the construction site and the amount of CO2 required to get it into its new position.

Considering the novelty of reusing concrete building components, the first step to developing the application was to create a so-called “object model” for creating and storing digital representations of physical building elements. This requires a sound understanding of the parameters that describe all relevant aspects (geometric, structural etc.) of the various types of elements (beams, columns, wall panels, slabs etc.). These parameters, element types and how they interact and relate to each other also help define the database schema for storing element information (i.e., the element library). A trial database was created and populated with element data from a recently completed deconstruction project – Prinsenhof A in Arnhem, the Netherlands.

A user can browse through a library of elements, import and position them in a Revit model to make up a new building design.

Subsequently, the focus shifted to developing algorithms for automatically connecting elements within the model, based on their relative locations, and for calculating structural forces and moments within all elements, based on expected floor loadings and the anticipated “load paths” that eventually take all forces down to the building’s foundations. Lastly, a framework for calculating the environmental impact resulting from using new and reused precast concrete building components will be developed and added to the application, to ensure that an environmental benefit is achieved for each reuse design, compared to a design consisting of newly manufactured elements.

Currently, the design application is developed as an add-on for Autodesk Revit. New building designs are therefore in the form of a Revit (.rvt) model, which can be easily converted to a more universal format such as Industry Foundation Class (.ifc). The design application is currently still under development, with a “proof of concept” prototype planned for the end of 2023.


June 19, 2023
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As part of the activities under Work Package 2 of the ReCreate project, our project partners developed a BIM-based pre-deconstruction audit. We sat down with Marcel Vullings from TNO to gain more insight into the audit and to get more details. Here’s our full interview with him:

 

I: What is the main focus of the pre-deconstruction audit in the ReCreate project?

M: The main focus of the pre-deconstruction audit in the ReCreate project is to gather and validate the information that is crucial for the deconstruction process. This involves putting significant effort into tasks such as inspecting archives, conducting inspections and testing, and ensuring the traceability of information. The goal is to establish a comprehensive understanding of the structure and elements involved, making connections between the gathered information and the actual components. By undertaking these steps, the pre-deconstruction audit aims to provide a solid foundation for the subsequent deconstruction activities.

 

I: What type of data is gathered during the survey of the existing building in ReCreate?

M: The pre-deconstruction audit process begins with gathering information from the archives to prepare for the building inspection. Once the necessary preparations are made, the next step is to inspect the building itself. Before conducting the inspection, it is important to strip the building of loose items such as carpets and wallpaper to ensure clear visibility of the structural elements. This provides an opportunity to thoroughly examine the structure.

During the inspection, several factors are considered. The overall state of the structure and its elements is assessed, looking for any signs of damage, cracking, or corrosion. Deviations from the norm are noted, such as brown spots that may indicate possible corrosion. Detailed documentation is crucial, including taking pictures and measurements of cracks and other issues. Videos are recorded to allow for a review of the inspection back at the office. Both overall views and close-ups of specific details are captured.

To ensure accurate understanding, it is important to make sense of the gathered information and create a cohesive narrative. Measurements of various dimensions are taken, and a comparison is made between the building’s drawings and its actual construction. Changes may have been made over time or during the building process. Digitalizing the building, its structure, and its elements is also part of the process, utilizing different types of measuring devices.

Finally, both the interior and exterior of the building are inspected to ensure a comprehensive assessment.

 

I: How is the identification system in ReCreate utilized to trace and couple physical elements with data?

M: Tracking and tracing each separate element is of utmost importance throughout the entire process. This is essential because when designing a new structure, structural engineers need to provide calculations, reports, and drawings to demonstrate that the structure is safe and compliant with regulations. Various checks, including those by municipalities, are conducted to ensure that each part of the structure performs as specified in the documentation.

For reused elements, the information associated with each element is crucial. Any mix-up or uncertainty regarding the information of a particular element can have severe consequences. Therefore, if there is any doubt about the information of an element at any point in the process, it cannot be reused and becomes useless. The objective, however, is to reuse elements whenever possible.

To achieve effective tracking and tracing, it is essential to connect the information to the corresponding elements such as columns, beams, walls, slabs, etc. This can be accomplished by attaching tags to the elements during the initial phases of deconstruction or up until the moment an element is deconstructed. It is crucial not to delay this process. The location of an element in the old structure serves as the only clue to establish the connection between the physical element and the associated information.

Tags can take the form of marks, such as barcodes, QR codes, or plastic tags placed on the elements. Alternatively, electronic tags can be used. These marks and tags need to be secure and durable enough to withstand deconstruction, transportation, storage, handling, reconstruction, as well as exposure to various weather conditions, heat, and sunlight. They must be foolproof.

In addition to secure marking, establishing and maintaining a robust connection with a database or information system is essential. Building Information Modeling (BIM) models of the elements can also be utilized to ensure a continuous and reliable link between the physical elements and their corresponding information.

 

I: Why is it important to identify hazardous and/or toxic materials before dismantling a building in the ReCreate project?

M: Strict regulations are in place to address hazardous and toxic materials, aiming to establish and uphold a healthy work environment for workers, ensure the well-being of the surrounding area, and contribute to a healthy overall environment. It is crucial to adhere to these regulations to create a safe and sustainable space. Materials falling under this category cannot be reused and must be handled separately and disposed of in a safe and environmentally friendly manner.

To effectively manage these materials, it is essential to determine their presence within the building. For instance, in the case of asbestos, special suits are required for safe removal. The process of identifying and dealing with hazardous materials is subject to scrutiny by the department of health. Mistakes in handling these materials can have severe consequences, including loss of life or significant fines.

Compliance with the regulations ensures the protection of both workers and the environment, emphasizing the importance of following proper protocols for the safe removal and disposal of hazardous and toxic materials.

 

I: What methods are used to record visual or detectable damage to elements in the pre-deconstruction audit?

M: At various stages throughout the process, the structure and elements undergo inspections to assess any damages, degradation, or cracking. These inspections occur from the initial assessment until the element is reassembled in a new building. The goal is to determine whether an element can be reused and ensure its proper performance throughout its new lifespan, which could extend for several decades or even longer.

Inspections rely on a combination of visual examination by experts, along with the use of pictures, videos, and electronic measuring devices such as point cloud measurements. Additionally, simple tapping on the surface of the concrete can provide valuable information. Specialized equipment like the Schmidt hammer and ferro scanners may also be employed for more detailed analysis.

However, it is crucial that these inspections are carried out by specialists, as not every crack or damage is necessarily catastrophic. Concrete structures commonly exhibit cracks, which are even accounted for and described in the eurocodes—design standards for concrete structures. The size and location of cracks play a significant role in assessing their impact and determining whether they conform to acceptable limits. Therefore, the expertise of specialists is vital in accurately interpreting the findings of these inspections.

 

I: How does the surveying process in ReCreate address stability issues during deconstruction?

M: Before carrying out the deconstruction itself, a structural engineer investigates the precast concrete structure to determine the optimal approach for dismantling the building, including the sequence of removing each element. This process must prioritize safety and ensure the stability of the remaining structure throughout the deconstruction process. To achieve this, a comprehensive deconstruction plan is created, which may involve implementing measures such as temporary scaffolding to stabilize the structure during the deconstruction phase.

 

I: What information does the survey aim to gather regarding the construction methods and structural systems of load-bearing elements?

M: This process can involve a considerable amount of technicality, but it can also be straightforward. Take, for instance, the location of a building, which provides valuable insights into its wind loading. Various factors differentiate a building situated at sea, inland, on an open plain, or within a city. Additionally, the dimensions of the building are crucial. Larger buildings must withstand greater and higher wind loads compared to smaller ones. However, for a structural engineer to accurately assess the load-bearing capacity of each precast concrete element, precise knowledge of the element’s location, layout, and dimensions is required. It is also essential to have information about the material properties of the steel and concrete, as well as how they are interconnected within the structure.

Furthermore, even the positioning of an element within the building, such as a column, provides relevant information. A ground-floor column typically exhibits greater load-bearing capacity than a column located at the top of a building. All of this information serves as valuable clues to determine the load-bearing capacity of each precast concrete element. The more comprehensive the available information, the more accurate the assessment becomes. In essence, if the dimensions of an element, a detailed description of the reinforcement, and the correct material properties are known, a structural engineer can reverse engineer the load-bearing capacity of that element. This process can be complex, but having additional information significantly simplifies it.

 

I: How does the acquired knowledge during the survey stage contribute to deconstruction planning in ReCreate?

M: Yes, this information is crucial for creating a deconstruction plan and ensuring the feasibility of the deconstruction process. Without it, the undertaking becomes unsafe and hazardous. A comprehensive deconstruction plan is essential, requiring detailed information about the building, structure, materials, connections, and the shape of the elements, among other factors. For instance, if the method of connection between elements is unknown, it becomes challenging to determine the appropriate cutting approach to separate the elements from the structure effectively. Consequently, incorrect cutting can lead to damage and render the elements unusable.

 

I: How does the pre-deconstruction audit combine modern survey technologies with traditional building surveying techniques?

M: During the audit, a wide range of methods are employed, with each task requiring its own specific technique. Various techniques and tools are utilized to simplify the process and gather accurate information quickly and reliably. These techniques and tools can be quite straightforward, such as visual observation, using a simple ruler for measurements, or employing a laser scanner to measure distances. Drones may also be employed to access challenging locations, such as high facades of buildings. Ferro scanners play a crucial role in detecting reinforcement within the concrete elements, while even a loupe can be utilized to measure the width of cracks in concrete. Additionally, pictures and videos are used to digitally measure elements. The available range of techniques and tools is extensive, offering a diverse array of options for conducting the audit.

 

I: What role does non-destructive electromagnetic and radar identification play in the ReCreate project, specifically during the survey of the donor building?

M: The non-destructive nature of obtaining information from precast concrete elements is evident, as the goal is to avoid damaging or destroying the elements in the process. Therefore, techniques employed to gather information must be non-destructive. In concrete, one critical aspect of obtaining information pertains to the location and dimensions of the reinforcement within the precast concrete element. These factors determine the element’s load-bearing capacity. Concrete elements require steel reinforcement, with concrete handling compression and steel managing tension—an ideal combination.

Steel can be detected using magnets, whether traditional or electronic magnets utilizing electromagnetics. A scanner is used to glide over the surface of the concrete, while the magnets detect variations and discrepancies. The scanner’s software interprets this information, providing readable details about the reinforcement within the concrete element. However, it is important to acknowledge the limitations of this technique. In certain situations, these methods may not be entirely reliable. To ensure accurate findings, it is essential to gather collaborating information from various sources, such as drawings, old calculations, and even resorting to destructive testing if necessary. Destructive testing involves breaking a portion of the element to visually examine it. Although this may result in sacrificing some elements, it becomes a last resort when other methods fail to provide satisfactory information.

 

I: How does ReCreate plan to bridge the gap from deconstruction to controlled disassembly for future buildings?

M: ReCreate plans to bridge the gap from deconstruction to controlled disassembly for future buildings through extensive data gathering and knowledge sharing. The project aims to learn from real-life pilot projects, examining what works, what doesn’t, and identifying areas for improvement. One important observation made during these pilots is that plastic tags are not suitable due to the fading of text under sunlight, rendering them unreadable. This highlights the need to explore alternative tagging methods.

Various methods of cutting through elements were explored, including sawing (using blades and cables), drilling, and high-pressure water jets. Each method has its pros and cons, and it is essential to understand and utilize them appropriately. There is no one-size-fits-all approach or tool for deconstruction. Efficiency and safety must be combined, taking into account the specific requirements of each project.

The ReCreate project, with its pilot projects conducted in different countries, aims to collect valuable data, information, and experiences. This wealth of knowledge is expected to have a significant impact, benefiting numerous projects in the future. TNO, as part of the project, plans to apply this new knowledge to other projects, including different types of deconstruction projects such as infrastructure, as well as exploring other materials like steel and wood structures. The research conducted within ReCreate has the potential for widespread application across various domains.

 

I: What role does cost-efficiency play in the development of the pre-deconstruction audit process in ReCreate?

M: Cost-efficiency plays a significant role in the development of the pre-deconstruction audit process in ReCreate. Currently, cost remains the primary factor driving the choice of methods for recycling concrete structures. Traditional demolition is often perceived as the cheapest option and, consequently, the most widely employed approach, despite its limited environmental friendliness. However, there is a need for a shift in societal mindset towards normalizing the reuse of materials and products as the first and natural step, rather than defaulting to purchasing new ones.

Lowering the costs associated with deconstruction and the reuse of precast concrete elements is a crucial objective. In this regard, ReCreate’s efforts are commendable, as the project strives to provide valuable services in enhancing efficiency within the field. Furthermore, implementing regulations and other measures can contribute to achieving cost efficiency and promoting sustainable practices in the industry. By addressing cost barriers and highlighting the economic benefits of deconstruction and material reuse, ReCreate aims to drive the adoption of more environmentally friendly practices in the construction sector.

 

I: How does ReCreate aim to optimize the detection methods in relation to the prefab systems and decoupling methods?

M: ReCreate aims to optimize the detection methods in relation to prefab systems and decoupling methods by considering them as additional tools rather than the sole approach. While detection plays a role, it is not the sole method employed. The study of original design drawings and calculations serves as the primary source of information for decoupling. Additionally, inspections and a comprehensive understanding of precast concrete structures provide a complete picture of the building. Detection techniques can be utilized to identify reinforcement in connections and other anchor systems where applicable. By integrating various approaches, ReCreate seeks to enhance the overall effectiveness of detection methods in relation to prefab systems and decoupling processes.

 

I: What is the significance of testing and validating the generic approach developed in ReCreate’s real-life pilot projects?

M: Testing and validating the generic approach developed in ReCreate’s real-life pilot projects holds great significance. It offers a comprehensive understanding of the entire deconstruction and reassembly process involving reused precast concrete elements. This includes all the associated aspects such as life cycle assessment (LCA), life cycle costing (LCC), compliance with regulations, development of business models, effective planning, information management, data gathering, innovative design approaches for structures using reused elements, creation of new connections, and the integration of old and new components through demountable connections.

The ability to observe these processes in real-life scenarios through four distinct pilot projects in different countries, involving diverse organizations and companies, provides invaluable insights. It allows for a thorough examination of the practical implementation of the generic approach, assessing its feasibility, effectiveness, and potential for scalability. These pilot projects serve as a robust testing ground, offering the opportunity to refine and validate the developed approach based on real-world challenges and outcomes. Ultimately, the knowledge gained from these pilot projects will contribute to advancing sustainable practices in the construction industry and facilitating the widespread adoption of the ReCreate project’s principles and methodologies.





EU FUNDING

“This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 958200”.

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