# Innovative Suspension Structures: The Role of Straight Elements Under Asymmetric Loads
## 4 Conclusions  
This article examines the design and analysis of rigid element suspension structures, with a particular focus on an innovative two-level cable-strut suspension system composed of straight, stiff bending elements subjected to asymmetric loads. Based on the analysis of these structural systems, the following conclusions can be drawn:  
1. A novel two-level suspension system has been developed, integrating straight, \"rigid\" elements in the upper chord and a specially shaped lower chord. This configuration stabilizes the initial geometry of the flat roof under both symmetrical and asymmetrical loads, while simultaneously enhancing operational performance.
2. The behavior of the lower chord under asymmetric loading was analyzed, leading to a revised calculation method for structural forces and displacements by dividing the displacements into kinematic and elastic. This approach minimizes the volume of iterative calculations required under asymmetric loading conditions. The axial force in the struts of the suspension system was found to be variable, depending on the bending stiffness of the upper chord, and the axial stiffness of the lower chord.
3. The Finite Element Method (FEM) analysis demonstrated that increasing the bending stiffness of the upper chord significantly decreases both the total displacements and internal stresses in the asymmetrically loaded system. Increasing the stiffness from P1 to I1 not only reduces deflections of the upper chord elements but also minimizes displacements at the nodes throughout the entire suspension structure. Notably, by selecting an appropriate bending stiffness for the upper chord, it is possible to prevent upward displacements or negative values of displacements in the central node and the unloaded part of the system even at high load ratios \(\gamma\).
4. Under asymmetric loading, the suspended strut system redistributes stresses between the upper and lower chords, effectively stabilizing displacements. The stresses in the loaded and unloaded parts of the upper and lower chords differ significantly. For a load ratio of \(\gamma=1.5\), the axial forces in the loaded part of the upper chord are approximately 2.17 times smaller than those in the unloaded part. Conversely, the axial forces in the loaded part of the lower chord are about 2.66 times greater than in the unloaded part. The bending moments in the upper chord also vary substantially: those in the loaded part are approximately 2.5 times greater than in the unloaded part. At maximum stiffness (I1), the total stresses in the loaded upper chord approach those in the unloaded part. Furthermore, the stresses in the most rigid element (I1) are approximately 3.67 times lower than in the least rigid element (P1), confirming the efficiency and rationale of employing rigid elements in this suspension system.  
Figure 16: Displacements of the conventional cable suspension structure (SK-4) under symmetric loading (solid line) and asymmetric loading (dashed line), with \(\gamma=1.5\).  
**Author Contributions:** Conceptualization, A.J.; Methodology, A.J. and A.D.; Software, A.D.; Validation, A.J. and A.D.; Formal analysis, A.J. and A.D.; Investigation, A.J. and A.D.; Resources, A.J. and A.D.; Data curation, A.J. and A.D.; Writing--original draft, A.J. and A.D.; Writing--review & editing, A.J. and A.D.; Visualization, A.J. and A.D.; Supervision, A.J. and A.D.; Project administration, A.J. and A.D.; Funding acquisition, A.J. and A.D. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Data Availability Statement:** The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflict of interest.