Cold-Formed Steel Truss Roof Structure Failure Considering Seismic Load and Buckling Analysis

Muslikh, Miftahul Iman — Fri, 29 Aug 2025 17:06:19 +0700

There were many incidents of cold-formed steel roof truss structures in the last 5 years in Indonesia. Various kinds of allegations have been addressed to cold-formed steel material applications especially in the case of seismic resistance. Some of them concern the authenticity of the steel material itself and the selection of cold formed steel material. On the other hand, recently, people have installed (assembled) cold-formed steel trusses without involving a certified cold-formed steel applicator. This research is based on a numerical study that modeled the collapse pattern of cold-formed steel truss roof structures by considering buckling failure and the seismic load capacity. The cold-formed steel roof truss structure was modeled with 3D-truss elements in two model types: the overall structure and a single compression member element in 3D solid idealization. Buckling analysis with eigenvalue and nonlinear static analysis was performed to evaluate the critical load (Pcr). The buckling mode shape also was also compared with the mode shape of modal analysis. This research also evaluated the effect of seismic load on the overall cold-formed steel truss structure and the slenderness of the compression member. The numerical simulation of cyclic loading on the single compression member was conducted in this research. The numerical analysis results showed that cold-formed steel roof truss structure have high vulnerability to seismic hazard effect. The cold-formed steel material has lower ductility than hot rolled steel material. This causes the lateral displacement that occurs to be lower than the displacement produced by the hysteretic curve of numerical cyclic simulation. This research also evaluated the dynamic properties, such as frequency, periods, and mode shapes, of some typical cold-formed steel for roof truss structure.

Evaluating the Role of Mechanical Connections and Reinforcements in Modular Timber Beam Behaviour

Mohd Rizuwan Mamat, Mohd Hisbany Mohd Hashim, Noorsuhada Md Nor — Tue, 16 Sep 2025 00:00:00 +0700

Modular timber construction faces critical challenges in connection performance, with mechanical joints representing the weakest structural elements in segmented systems, particularly for rapid-deployment infrastructure applications such as temporary forest bridges. This research addresses the fundamental knowledge gap regarding the combined effects of mechanical connections and reinforcement strategies on modular timber beam structural behavior. The study investigates modular timber beam flexural performance through experimental evaluation of steel U-shaped connectors and Chopped Strand Mat (CSM) reinforcement applied to the tension zones, examining how beam segmentation affects structural integrity. Ten I-section modular timber beams with lattice-web configuration underwent three-point bending tests using a Shimadzu AG-IS 100 kN Universal Testing Machine at 6.6 mm/min loading rate, with specimens spanning 3.0 meters supported at 2.7-meter intervals. Test specimens featured varying segmentation patterns (0.6m, 0.75m, 1.0m, and 1.5m segment lengths) connected via U-shaped steel connectors and bolts, with selected beams receiving 5mm thick CSM reinforcement at the bottom flanges. Mechanical properties including modulus of elasticity (MOE), modulus of rupture (MOR), and flexural stiffness were systematically measured to quantify reinforcement and segmentation effects on joint behavior and structural continuity. Results demonstrate that CSM reinforcement provides substantial performance improvements, with ETR136 achieving a 49% increase in ultimate load capacity (29,397 N vs 19,709 N for ETN131) and superior ductility characteristics. However, segmentation introduces significant structural vulnerabilities, with five-segment beams (ETN50.65) showing a 49.5% capacity reduction compared to continuous specimens. The research reveals that while CSM reinforcement effectively delays crack initiation and reduces peak tensile strain by an average of 31%, mechanical joints remain critical failure points due to stress concentrations at the timber-bolt interfaces. The three-segment configuration emerges as optimal for balancing structural performance with practical modularity requirements. These findings provide essential design guidance for modular timber systems in rapid-deployment applications, emphasizing the need for optimized connection strategies and hybrid reinforcement techniques to enhance the structural integrity and durability of segmented timber infrastructure.

Journal of the Civil Engineering Forum

Cold-Formed Steel Truss Roof Structure Failure Considering Seismic Load and Buckling Analysis

Evaluating the Role of Mechanical Connections and Reinforcements in Modular Timber Beam Behaviour