What information is necessary to assess the environmental impacts of deconstruction?

4D modeling - the simulation and visualisation of the construction process - is now a common method used during the building construction process with reasonable support from existing software. The goal of this paper is to examine the information needs required to model the deconstruction/demolition process of a building. The motivation is the need to reduce the impacts on the local environment during the deconstruction process. The focus is on the definition and description of the activities to remove building components and on the assessment of the noise, dust and vibration implications of these activities on the surrounding environment. The outcomes of the research are: i. requirements specification for BIM models to support operational deconstruction process planning, ii. algorithms for augmenting the BIM with the derived information necessary to automate planning of the deconstruction process with respect to impacts on the surrounding environment, iii. algorithms to build naive deconstruction activity schedules

Secondary raw material markets in the C&D sector: Study on user acceptance in southwest Germany

In industrialized countries, regulations demand increasingly higher recycling (RC) rates and many efforts are undertaken to recycle construction and demolition (C&D) waste fractions. The C&D sector has indisputable relevance due to the highest mineral waste fraction, high numbers of employees and turnovers. High-quality RC construction products can be produced to substitute primary resources and reduce land use. This empirical study analyses the acceptance of RC materials in Germany particularly of private awarding authorities in their private construction project(s). In 41 structured interviews, data is collected and evaluated based on hypotheses. Qualitative and quantitative analyses show that acceptance problems cannot be stated. How-ever, medium knowledge and low experience with RC construction materials as well as communication problems are identified. The respondents have no concerns and tend to trust in RC construction materials, but this is decreasing with the increased structural importance of the materials. Surprisingly, quality is the most frequently mentioned decision criteria in private construction projects, followed by cost. Private awarding authorities see no increase of their property value by using RC construction materials. And, the majority is unwilling to pay a premium for RC construction materials. Higher material quality standards, regular government reviews and financial support are seen conducive

On the integration of diverging material flows into resource‐constrained project scheduling

This study deals with an extension of the resource-constrained project scheduling problem (RCPSP) by constraints on material flows released during the execution of project activities. These constraints arise from limited processing capacities for materials and maximum inventories of intermediate storage facilities. Production scheduling problems with converging material flows have been studied extensively. However, this is the first project scheduling problem integrating diverging material flows typically observed in dismantling projects, e.g., building deconstruction, power plant decommissioning, or battery/car decommissioning. Diverging material flows do not directly impact the project planning but only impose delays in the case of congestion. We model material flows by using operations that represent the processing of materials, and cumulative resources that represent storage facilities. As a method for efficiently generating starting solutions, we propose a schedule generation scheme tailored to the particular precedence structure of such problems. Furthermore, we extensively study the schedule generation scheme’s performance on generated test instances and compare it to the constraint programming solver IBM ILOG CP Optimizer. It turns out that the solution quality strongly depends on the employed model and that neither of the two solution methods is generally superior

Instance dataset for resource-constrained project scheduling with diverging material flows

This data article describes an instance dataset motivated by the problem of scheduling a project with diverging material flows. Such material flows are released during the execution of the project and are subject to limited processing and storage capacities. Typical examples are nuclear dismantling or other deconstruction/demolition projects, where large amounts of material must be classified, scanned for hazardousness, and processed accordingly. The problem setting is mathematically described as a resource-constrained project scheduling problem with cumulative resources (RCPSP/c). The RCPSP/c deals with finding a project schedule with minimal makespan that satisfies temporal, renewable resource, and cumulative resource constraints. In total, the dataset comprises 192 artificially generated instances that are suitable for testing models and solution methods. In addition, we provide our best found solution for each instance and different modeling variants (e.g., for two types of objective functions). These solutions were computed by heuristic solution methods. The dataset serves as a benchmark for researchers evaluating the performance of solution methods for the RCPSP/c or the more general problem class with resources that can be produced and consumed

Risk Differentiation for Critical Infrastructure Protection

Critical infrastructures, e.g., electricity transmission / distribution, public transport and health care systems, need to be protected against various internal and external risks which can be safety- and / or security-relevant. Predominately probability-based methods are hitherto used for analysing the whole spectrum of risks. We think this is an insufficient approach, presumably leading to inefficient resource allocation and biased risk perception, as it does not consider the different natures of risk. This paper looks at the key difference between safety- and security-relevant risks, highlights resulting implications for critical infrastructure protection and describes a possible approach for handling these different types of risk