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The load features of ground motion are mainly reflected by three factors: amplitude, frequency, and duration. The combination of these factors determines the response of rock-soil mass and the structure safety under seismic load. By finite element method, this paper analyzes the influence of the three factors of ground motion on the dynamic response of a slope. The analysis shows that the slope displacement increased with the elevation from the bottom. The anti-dip fault puts the slope in an unfavorable deformation state. Due to the large residual deformation in the fault zone, a large displacement occurred on the slope top. It was also learned that the adjustment of amplitude only leads to proportional growth in the absolute value of the acceleration of the slope. Under the same conditions, the dynamic responses in different parts of the target slope are not greatly affected by the changing amplitude, but depend more on the material and spectral features of the rock-soil mass. The research results provide a reference for the evaluation and prediction of slope seismic stability and the evolution of slope damage under earthquakes with different frequencies, amplitudes, and durations. [ABSTRACT FROM AUTHOR]

Resonance avoidance is an important topic in engineering seismic design. However, there is little report on the resonance features of rock slopes with anti-dip weak rock layers under seismic actions. Through finite-element method, this paper carries out modal analysis and harmonic response analysis on a slope, captures the natural frequencies and vibration modes of the slope, and plots the resonance curves about displacement frequency relationships. The results show that slope resonance is greatly affected by damping ratio: the greater the damping ratio, the lower the resonance peak; the inverse is also true. This means that weak and broken rock mass is capable of absorbing shocks, but not necessarily easy to be damaged. On the contrary, broken rock mass has poor mechanical performance and is prone to damage under small vibration. Besides, the resonance effect of the slope is mainly excited by the natural frequencies of the first three orders; the vertical resonance displacement peaked at about 1.1 Hz, while the horizontal resonance displacement peaked at about 1.38 Hz. From the vibration modes and frequency response curves, the resonance peak of the slope is amplified in the vertical direction and on the free face, and the maximum resonance displacement appears on the surface of the slope, indicating that the strongest resonance occurs on slope surface. This research fully clarifies the stability and dynamic response law of rock slopes with anti-dip weak interlayer under seismic actions, laying a solid basis for the mic fortification, landslide prediction, and landslide control of slopes. [ABSTRACT FROM AUTHOR]

Due to the brittle nature of wood material, the dissipation of seismic energy in timber structures is typically ensured through yielding of the mechanical connectors, where plastic deformations are developed in fasteners that have adequate ductility and cycle-fatigue strength. These structural components are denoted dissipative zones, whereas all other structural elements are assumed to behave elastically. Such elements are designated as non-dissipative zones and are designed with sufficient over-strength, to meet the requirements of capacity-based design (CD). Despite the general consensus that using the principle of CD could lead to safe buildings, where brittle failures are avoided, the applicability of such approach to light frame timber (LFT) and cross laminated timber (CLT) buildings has lacked analytical expressions that depend on the structural typology and failure mechanism. The current paper aims to fill this gap in knowledge by proposing an analytical approach that incorporates the CD philosophy to LFT and CLT buildings at the substructure (wall) and super-structure (building) levels. A simplified approach is adopted for structures with a low-to-medium energy dissipation capacity whereas a more rigorous approach is presented for structure with a high energy dissipation capacity. An experimental comparison and design example is included to present the applicability of the proposal. [ABSTRACT FROM AUTHOR]

During seismic events, the gravity loads may cause a reduction of the lateral stiffness of structures; inelastic deformations combined with horizontal loads ( P -Δ effect) can bring to a state of dynamic instability that obviously influences building safety. Especially for flexible structures, the P -Δ effect amplifies structural deformations and resultants stresses, and thus may represent a source of sideway collapse. Since this type of collapse is the result of progressive accumulation of plastic deformation on structural components, the specific objective of this works is to study this effect on a three floor metallic frame (made of aluminium alloy). A non-linear finite element (FE) model of the frame has been developed to study the dynamic non-linear behaviour of the structure, and compare it with the experimental results obtained from a scaled model of the real structure. The FE model, where a simple isotropic hardening behaviour was assumed for the material, was not able to reproduce the real behaviour of the structure. Rather, the correct description of the cyclic plastic behaviour of the material was essential for the numerical analysis of the structure. The characterization of the non-linear behaviour of the material was made by cyclic tension–compression tests on material specimen, from which the coefficients of Chaboche's model were properly calibrated. In this way, the finite element model of the structure provided results in optimum agreement with the experimental ones, and was able to predict the lateral collapse very well. [ABSTRACT FROM AUTHOR]