# Ecological and Economic Assessment of the Reuse of Steel Halls in Terms of LCA
## 3 Subject of the Research, Basic Assumptions  
### Stage I (Defining the Purpose and Scope)  
The design and material assumptions in Sections 2.1 and 2.2 apply to selected model steel structures to test the EET method. Four static schemes of typical halls found in the investment market were adopted. The LCA path was analyzed on single-span structures in modular span variants ranging from 12.0 m to 48.0 m.  
Stage II (LCIA-Life Cycle Inventory Analysis): Determination, Collection and Analysis of the Required Data  
Physical and computational data (Materials and geometry). The selection of the shape and dimensions of the halls adopted for the analysis was determined, assuming the typical solutions encountered in practice and the optimization work of steel frames [12, 54]. The considered structural systems of halls consist of transverse flat frame structures connected with each other by bracing systems. In the analysis below, the transverse structural systems were examined, adopting, for their general stability, the buckling lengths that correspond to the node spacing of the longitudinal and transverse bracings of the halls [55]. This study did not analyze halls with a cooperating roofing made of a corrugated sheet (with the so-called diaphragm) as systems with an increased degree of difficulty in disassembly, which makes them less useful for the needs of multiple assembly. However, this does not prejudge the use of such solutions. The following geometrical parameters of the bars and the design parameters of the hall nodes were adopted, which created the following flat static diagrams (Figure 2):  
- \"A\" scheme--rigid frame;  
- \"B\" scheme--frame with rigid columns on the support and articulation at the transom;  
- \"C\" scheme--triple-joint frame;  
- \"D\" scheme--rigid frame at the transom column nodes and articulated on the support. Material data:
* Steel profiles of the hall cross system: HEA prismatic profiles,
* Type of structural steel: St3S (mullions, transoms, gusset plates, welds),
* Foundations: Concrete C16/20 (B-20), structural steel A-II. Technical parameters for the adopted research models:
* height H = H1 + H2 [m], (H1 = 4.5 m, H2 = 1.5 m). - frame spacing S = 5.0 m.
- variable span, the same for each scheme, from L = 12.0 m to 48.0 m.
* Loads--equal for each scheme, i.e., wind, snow, roof loads, including purlins and bracings. * Own weights--suitable for the structural scheme. * Support compliance was presented as the intended relative displacement of support A with permissible values dx = \(-\)2 cm and dy = 2 cm (due to the disassembly conditions and the changeability of settlement during re-foundation). * foundation level hp = 0.80 m. p.p.t.,
- soils with low bearing capacity (Pd--Id = 0.3, \(\varphi\) = 15\({}^{\circ}\), \(\rho\) = 1.65 t/m\({}^{3}\)),
- strong soils (Pav--Id = 0.60, \(\varphi\) = 31\({}^{\circ}\), \(\rho\) = 2.00 t/m\({}^{3}\)). 1. Static calculations were made with the use of the ROBOT computer program. Dimensioning of the steel structure of the halls is based on [40,41]. 2. Design of foundations according to [41,42],
3. The price of construction and assembly works--as the average values from I quarter 22\({}^{\prime}\), the following were adopted: - data for the steel skeleton (as of 03.2022) [43] (initially adopted to be produced with the material 12.76 euro/kg, assembly 1.5-3.5 euro/kg, material 8.50 euro/kg); - for reinforced concrete foundations (workmanship, material)--100.00 euro/m\({}^{3}\), the execution with the material was initially adopted. 4. Other data according to technical standards and norms. In the present study, it was assumed that the welds maintained the boundary conditions for individual frame nodes [56]. The welds were dimensioned for extreme cross-sectional forces at individual stages of structure operation, in accordance with [57,58], assuming the minimum weld mass [58,59,60,61,62] as the main optimization criterion. The index-formability of the substrate was assumed in the calculations.