Economic Feasibility of Reusing Structural Components

Abstract

The Netherlands has the vision to be completely circular by 2050 cutting its raw material consumption to half by 2030. To reduce the raw material consumption, materials in use must be reused and nothing should be wasted. However, the construction industry is far from reaching this goal. It is traditional in the EOL treatment of the building. The structure is crushed down into mixed debris and recycling is the highest level of waste management adopted in the sector. 85% of the CDW in The Netherlands is mineral waste which is crushed and typically applied as the foundation in road construction. Reuse, a higher level treatment method, is rarely adopted. Only 3%-4% of the total material demand in the industry is met with secondary materials. It is limited to the reuse of products such as doors, windows and interior installations.
Existing demolition methods do not allow for product recovery as it a costlier and time- consuming process. It requires skilled labour, knowledge and collaboration amongst the stakeholders to deconstruct for reuse. The limited knowledge of the know-how of recovering structural components is found to be prevalent. Furthermore, there is no tool or framework to quantitatively assess the economic feasibility of reusing components well before demolition.
The available methods for assessing reuse feasibility are found to have a futuristic approach and cannot assess the economic feasibility quantitatively. Therefore, the Feasibility Calculation Tool is developed in this research which is a practical framework capable of quantitatively assessing the reuse potential of the components. It provides clear guidance to stakeholders on how to assess if the components from existing buildings can be profitably extracted for reuse. The FCT can be successfully used to determine the economic costs and feasibility conditions quantitatively allowing for a circular EOL treatment. The reuse scenario and the tipping points for the structural floor elements can be evaluated well in advance of demolition guiding the decision of the owners to demolish or deconstruct for reuse. A well-planned deconstruction can further help find buyers in time and deconstruct with higher precision as per the requirements of the buyers increasing the salvage cost and the need to modify components after deconstruction.

The results of FCT show that it is most feasible and economic to reuse components directly on the same site (Reuse Scenario 1) then to transport them to another site for reuse(Reuse Senario 2). However, for the existing building stock, it is more probable to reuse under Reuse Scenario 3 than 2 and 1 as the
existing stock is not designed to be reused. Instead, a buyer should be found who has no or minimum modification requirements. Furthermore, taking the environmental impact of reusing secondary components into account improves the reuse feasibility. The reuse cases which are otherwise not economically feasible turn feasible once the environmental impact costs are considered, in other words, once the polluter is made to pay the price. Furthermore, planning for the EOL of the building should be done well in advance
to allow for sufficient time and efficient recovery. The owner should be motivated for deconstructing circularly, allow sufficient time and if he fails to reuse materials himself, he should allow for collection and sale of secondary products by the demolition companies to a third party. The demolition contractors, on the other hand, are found to depend on the question from the owner to reuse. However, they must make voluntary calls for deconstruction.