By employing the frequency-wavenumber (FK) method to simulate the propagation of seismic wavefield in the crustal layer, using the spectral element method (SEM) to simulate the propagation of wavefield in the near-surface soil, and using the multi-degree-of-freedom (MDOF) model to simulate the seismic response of building clusters in city, this paper establishes the FK-SE-MDOF approach (a two-step method) for urban earthquake disaster analysis of fault-to-city based on the concept of domain reduction. The approach can simultaneously consider factors such as earthquake source parameters, propagation paths, local site effects, site-city interaction (SCI) effects, and the dynamic nonlinear responses of buildings (hereafter referred to as source-to-city factors) in a physics-based model. Firstly, the theories of the approach were introduced, and the correctness of the approach was verified. Furthermore, the applicability and the necessity of considering source-to-city factors were examined using a building cluster on an ideal sedimentary basin under the action of a point dislocation source. Finally, the seismic response of buildings in a region was simulated using buildings in the Nankai District of Tianjin as examples. This approach avoids the influences caused by expert experience differences in empirical and hybrid methods, establishes a connection between fault rupture and buildings dynamic response, and can more realistically reflect the distribution of seismic wavefields, building seismic responses, and damage state distribution under the earthquake scenario. It can be applied to earthquake disaster simulation for urban buildings at the scale of tens of thousands of buildings, and the simulation results can provide quantitative guidance for urban planning, earthquake-resistant design, risk assessment, post-earthquake rescue, etc.

Advances in the design process and understanding of the structural behaviour of jacket -type foundations for offshore wind turbines are fundamental to the expansion of these devices in medium -depth waters. The structural evaluation of jacket foundations is a complex and computationally expensive task because of the large number of structural elements and numerous load scenarios and requirements imposed by international standards. In this context, the soil-structure interaction is not usually incorporated into the optimisation process of these devices, assuming that the foundation flexibility does not significantly affect the supporting structure. This study investigated an approach for analysing the influence of the soil-structure interaction on the structural design. To perform a relevant analysis, an optimisation process was used to obtain feasible designs for a 10 -MW wind turbine in a specific location. To optimise and evaluate the jackets, a structural model based on static equivalent analysis of the most representative load scenarios for environmental loads was used. The obtained designs highlight the importance of considering the soil-structure interaction for evaluating the technical requirements imposed on these structures, especially in the ultimate limit states.

The increasing impact of global climate change has resulted in adversity stresses, like salt and drought, gradually becoming the main factors that limit crop growth. Hemp, which contains numerous medicinal active components and multiple bioactive functions, is widely used in the agricultural, industrial, and medical fields, hence promoting the rapid development of related industries. Arbuscular mycorrhizal fungi (AMF) can establish a symbiotic relationship with 80% of vascular plants. This symbiosis promotes host plant growth, regulates plant physiology and biochemistry, facilitates secondary metabolite synthesis, and enhances resistance to abiotic stresses. However, the effects of salt stress, drought stress, and AMF interaction in hemp are not well understood. In this study, to investigate this, we performed a study where we cultured hemp that was either inoculated or uninoculated with Funneliformis mosseae and determined changes in effective colonization rate, growth, soluble substances, photosynthesis, fluorescence, ions, and secondary metabolites by cultivating hemp under different concentrations of NaCl (0 mM, 100 mM, and 200 mM) and different soil moisture content (45%, 25%, and 15%). The results showed that salt, drought stress, or salt-drought interaction stress all inhibited colonization rate after stress, plant growth, mainly due to ion toxicity and oxidative damage. Inoculation with F. mosseae effectively alleviated plant growth inhibition under 100 mM NaCl salt stress, drought stress, and salt-drought interaction stress conditions. It also improved osmoregulation, photosynthetic properties, fluorescence properties, and ion homeostasis, and promoted the accumulation of secondary metabolites. However, under 200 mM NaCl salt stress conditions, inoculation with F. mosseae negatively affected plant physiology, biochemistry, and secondary metabolite synthesis, although it did alleviate growth inhibition. The results demonstrate that there are different effects of salt-drought interaction stress versus single stress (salt or drought stress) on plant growth physiology. In addition, we provide new insights about the positive effects of AMF on host plants under such stress conditions and the effects of AMF on plants under high salt stress.

In recent years, strong earthquakes have caused a lot of damage around the world. In order to prevent such damage, proper evaluation of the seismic performance of buildings is absolutely necessary. However, the current analysis procedure in seismic design assumes fixed boundary conditions for the foundation and neglects the influence of the substructure on the superstructure. Previous studies have shown that the type of foundation affects structural responses during earthquakes. However, most of these studies have focused on single-degree-of-freedom (SDOF) structures and have not considered variations in response according to different substructure types. This study aims to investigate the effects of different substructures on ground motion and corresponding responses of the superstructure. Centrifugal simulations were conducted on a multi-degree-of-freedom (MDOF) superstructure, including a Half-embedded with Pile foundation, a fixed deep basement, and a Shallow foundation. The experimental results indicate that in the case of a half-substructure with a pile foundation, there was no significant difference between free field motion and foundation motion due to the pile foundation. However, in the case of a fixed deep basement, the embedment effect was most pronounced, especially in the short period range of 0.1 s to 0.5 s in the response spectrum. This resulted in a notable reduction in the spectrum. The analysis of the response spectra of foundation motion and free field motion revealed that the reduction effect was absent in the half-embedded with a pile foundation, but it was prominent in the fixed deep basement. Notably, the ratio of response spectrum increased in the fundamental period of the substructure. In the case of a shallow foundation, it was observed that foundation motion experienced larger amplification compared to free field motion. Shallow foundations have a relatively low stiffness of the substructure and are influenced by the inertial forces of the superstructure. Additionally, this tendency is believed to be more prominent due to the imperfectly fixed boundary conditions of shallow foundations to the ground. However, apart from the increase in foundation motion, the response of the superstructure was not proportional to it. These results contribute to a better understanding of the changes in seismic load and the response of multi-degree-of-freedom superstructures according to the type of substructure. The seismic design of the superstructure is safer and more reasonable when considering the effects of the type of substructure.