The Netherlands is currently in the process of transitioning from a linear economy to a circular economy, in accordance with the ”Nederland Circulair 2050” policy. To increase the circularity of buildings, several approaches can be integrated. In this research, the so-called Design for Deconstruction and Donor Structural Framework concepts are elaborated as possible approaches. The first concept focuses on taking the future de- and remountability of a building into consideration during the design process. This concept allows buildings that approach their end-of-life phase to be (partially) reused as structural components, on a new location. The second concept can be applied during the construction phase of a building, where structural components of an old building are dismantled and reused in the to be constructed building. The difference between the two concepts thus being the life cycle in which they are applied. Therefore, the resulting benefit of using a Donor Framework can be seen immediately, whereas the benefit of applying the Design for Deconstruction concept can only be stated in the future. Unfortunately, the current procedure to measure the sustainability score of a building, the Life Cycle Assessment methodology, does not take these concepts into account. This makes determining their impact on the environment hardly possible. Also, due to the fact that detailed information about a design is required, a Life Cycle Assessment is made only once the design is final. In this order, all design variables are set such that designing towards sustainability is not an option. This research focuses on solving the introductory problems and aims to enable sustainable material choices for a structural design possible in the early design phase. Both the Donor Structural Framework and the Design for Deconstruction concepts were taken into consideration. This main goal has been split into two sub–questions:- How to assess the environmental impact of a steel, concrete and timber load bearing structure in the early design phase? -How to implement the Donor Structural Framework and the Design for Deconstruction concept into the existing Life Cycle Assessment methodology? The research questions have been answered by executing the following approach: 1.A parametric model is used in which not only the geometry and structural calculations are included, but the Environmental Impact Calculation as well. In the event of a design change, the Environmental Impact Calculation is automatically reiterated, which means different designs can be compared quickly based on their environmental impact. The model constructed for this study is suitable for designs in steel, concrete and timber. For each material a reference design is created. The Bill of Materials of these designs serves as input for the Environmental Impact Calculation on which the materials were compared in a later research phase.2.First, an existing end-of-life allocation method has been adjusted to include reuse during both the construction phase (Donor Structural Framework) as the end-of-life phase (Design for Deconstruction). Secondly, the Building Circularity Index, which recognizes a ”circularity score”, has been implemented in this method. In this study the Building Circularity Index is assumed as the ”probability of future reuse of the building”. The modified method was implemented in the parametric model to enable a real-time Environmental Impact Calculation. This approach has been fully implemented into a parametric visual script, executed in the Grasshopper, a parametric environment plugin of Rhino which enables visual scripting. Input parameters are imported from Excel, the Grasshopper script calculates the environmental impact and exports the results to Excel where they are visualized in a dashboard. Ultimately, the developed parametric model has been divided into a part containing the geometry and structural calculations of the reference designs and a part where the newly developed Environmental Impact Calculation method is implemented. Combining the results of both parts in the total model, it becomes possible to assess whether a design is best built in a certain material in the early design phase. The final model can provide results with or without the use of a Donor Structural Framework and with or without application of the Design for Deconstruction concept. For the purpose of demonstrating the functioning of the model, a reference design in steel, concrete and timber was implemented as a basic geometry. This geometry was assumed equal across all designs and for comparability purposes, dimensions were fixed. Consequently, it can be concluded from the results of these reference designs that using a Donor Structural Framework results in a lower environmental impact than applying the Design for Deconstruction concept by maximizing the remountability of a structure. Until a lifespan of 75 years, using a timber donor framework is the most sustainable solution for the reference design. From 75 until 100 years this is the case for steel and from 100 years onward, a concrete design, whether or not using a donor framework, results in the lowest environmental impact. In the current design practice of a building, the default lifespan has been determined by the function of the building (Functional Service Life). By using the model developed here, this lifespan can be determined on the basis of sustainability requirements instead of functional requirements. The differences in environmental impact for different lifespans can easily be compared. Therefore, it is made possible to steer towards a certain lifespan, in order to determine the most sustainable construction based on the clients requirements. This is currently not possible in the Dutch construction industry. However, these results do have their limitations, as they should not be interpreted as general but rather specific conclusions. The following points of attention apply: -Results should not be interpreted as general results, but these results only apply on the three reference designs as elaborated further in the research. These reference designs are not optimized for every material used. -Changing input parameters can have a significant impact on the results. In addition, a number of important parameters (reuse percentage, material lifespan etc.) have been assumed due to insufficient existing research. -The developed allocation equations include the incineration of timber too favorably. This results in a significant deviation in timber environmental impact for lifespans much shorter than 75 years. This flaw can be either due to the model, or the impact parameters as stated in the NIBE EPD app. Lastly, it is recommended to further research the assumed parameters in this research, especially the material lifespan and the incineration impact parameters. As these parameters can have a major impact on the environmental impact of a specific design. ... Read more

After the earthquake in 2015 that struck Nepal, students of the Delft University of Technology commenced the multidisciplinary project program “Shock Safe Nepal”. This report describes the effort of the sixth group of students who travelled to Nepal. Following conclusions and specific recommendations of Team 5, the present research has one main goal. This research focuses on improving the overall quality of CSEB and making sure that the final strength of the bricks is constant. This is done by predicting the final strength of CSEB during the early curing stage and using this knowledge to develop a testing method, so the Nepali can monitor the CSEB quality easily and accurately on site in an early production stage. The secondary goal was to perform a dynamic seismic analysis of the pilot house in Ratankot and to get a better understanding of earthquake engineering in Nepal.

To predict the final strength of CSEB, a research into the existence of a drying/hardening curve was performed. Different regions in Nepal ask for different CSEB mixtures because of differences in humidity, temperature, altitude and soil consistency. The biggest influence of the change in hardening process is presumably the cement percentage and therefore also the water/cement ratio. In the Nepali practice this percentage is between 5 and 15 percent, depending on local soil type. Therefore, in this research all soil parameters were kept constant except cement percentages, they range from 5 till 15 percent. To develop a hardening curve, bricks were tested after 5, 8, 14, 21 and 28 days. This was done using a (calibrated) compression machine. Results of these tests showed wide spread. The tested bricks were still moist and it was decided to test the CSEB after 38 days as well. This resulted in an even bigger gain in strength such that the bricks after 38 days were twice the strength of the bricks after 28 days.
General conclusion can be drawn that the time period between the curing and testing of the brick makes a significant difference in the results, so this has to be monitored accurately. Furthermore continued curing does not necessarily contribute to the strength of the bricks or might even have a negative effect.

Results from the compression test showed that the general quality, and thus compression strength, of the bricks was lacking. Only bricks with 15% cement surpass the minimum strength of 3.50 MPa after 38 days. This showed that production site was not working properly, therefor Build Up Nepal was informed. This lack of strength is probably caused by a change in variables. The weather in the winter is very different than in summer, but the curing process wasn’t modified. Also the soil composition differs every time new soil is brought to the site, which can change the strength drastically.

While researching the hardening curves for CSEB, an alternative testing method was developed. Multiple ideas have been tested, such as a torque wrench with vice, a drop test and finally a lever arm test. The first two methods were deemed unusable as they broke down or were not able to produce reliable results. The lever arm test was most promising as this method produced constant results. Against expectations, the strength of the bricks tested by the lever arm tested was much higher than the strength of the bricks tested with the compression tester. This indicated that not exactly the same properties were measured. The results cannot be directly compared to each other. Before the method can be implemented there is more research necessary about which property is tested with the lever arm and the converting factor.
... Read more