Experimental Investigation and Numerical Simulation of a Levy Hinged-Beam Cable Dome

According to existing rigid roofing projects, a new structure called the Levy hinged-beam cable dome is proposed. By replacing the upper flexible cables with hinged beams, rigid plates can be installed overhead. To fulfill the requirements of integral tow-lifting construction, the setting criteria for the temporary hinged joints on ridge beams were presented. An 8-m diameter specimen was manufactured and monitored to investigate the structural configurations during the accumulative traction-hoisting construction process. Finally, the specimen was tested under full-span and half-span loading conditions, while a numerical model was built to verify the experimental values. The results show that in the early stages of traction-hoisting, the structure establishes the overall prestress and finds its internal force balance, while the entire structure is in a shape of “ω”. As the component’s internal force increases during the construction steps, and the local deformations of the hinged beams gradually decrease, with the entire structure changing from “ω” to “m”, and finally reach their designed states. Under full-span loads, large local deformations occurred at the HB-3 hinges, while the bending stresses of these hinged beams were relatively small. Under half-span loads, the loading part exhibits a downward appearance, while the unloading part exhibits upward deflection.

Influence of Bimoment Restraints on the Load-Bearing Capacity of a Steel I-Beam

The study presents an analysis of steel I-beam warping. The calculations were made for hot-rolled IPE200 hinged beams with different lengths. After determining load-bearing capacity using the GMNIA method, the beams were strengthened with bimoment restraints at each end. The changes in critical moment and load-bearing capacity were then evaluated. The study presents the manner in which the material and geometric imperfections have been determined. The GMNIA calculations were conducted using the Finite Element Method in Abaqus software. The results were then compared to results obtained with traditional methods and acquired from LT Beam software.

Linear theory for beams with intermediate piers

The full linear theory for hinged beams with intermediate piers is developed. The analysis starts with the variational setting and the study of the linear stationary problem. Well-posedness results are provided and the possible loss of regularity, due to the presence of the piers, is analyzed. A complete spectral theorem is then proved, explicitly determining the eigenvalues according to the position of the piers and exhibiting the fundamental modes of oscillation. A related second-order eigenvalue problem is also studied, showing that it may display nonsmooth eigenfunctions and that the fourth-order problem cannot be seen as the square of a second-order problem.

Moving-Inertial-Loads-Induced Dynamic Instability for Slender Beams Considering Parametric Resonances

This paper investigates the moving-inertial-loads-induced dynamic instability limit for transverse bending vibration of slender beams considering both simple and combination parametric resonances under disturbances on multiple modal coordinates. The vibration system is described in the modal domain using ordinary differential equations with periodic parameters. Straightforward expansion is conducted to analyze the possible resonance regions. The impulsive parametric excitation method is employed to compute the monodromy matrices. System dynamic stability is evaluated and the transition curves are computed. Numerical studies on single-span clamped–clamped and clamped–hinged beams considering the first two modes are conducted. The computed dynamic instability maps verify the analytically derived resonance occurrence conditions and present the following observations. The initial disturbances on multiple modes will induce variation of the parametric resonance instability region and create new resonance tongues. Among all resonance tongues, principal simple and sum combination resonance tongues are the most important. For the mitigation of combination resonances, damping measures are required to be applied on all related modes.