Honghao Li

Large-scale mining of graphite, a crucial strategic mineral, generates substantial amounts of graphite tailings (GT). The stockpiling of this solid waste occupies vast land resources and poses persistent environmental risks due to potential heavy metal leaching. Repurposing GT into construction materials presents a promising solution, with its use as a partial replacement for fine aggregates in cementitious composites being one of the most effective methods. This review systematically consolidates current research on graphite tailings cement mortar (GTCM) and graphite tailings concrete (GTC). Due to its physicochemical properties comparable to natural sand, GT is suitable for producing building materials. Studies consistently demonstrate that a substitution level of 10% to 20% optimizes overall performance. This optimal range enhances particle packing, promotes cement hydration via pozzolanic activity, and refines the microstructure, leading to improved workability, superior mechanical strength, and enhanced durability, including resistance to permeability, freeze–thaw cycles, and chemical attacks. Moreover, the inherent carbon content imparts electrical conductivity to GTC, enabling functional applications like de-icing and structural health monitoring. The successful utilization of GT also extends to lightweight foamed and autoclaved aerated concrete. However, research on the structural behavior of GTC components remains limited. Preliminary findings on beams and columns are encouraging, but comprehensive studies on their seismic performance and design methodologies are urgently needed to facilitate the widespread engineering application of this sustainable material and mitigate the environmental impact of tailings accumulation.

Traditional villages are important parts of architectural and material cultural heritage in China. This study focuses on 710 national-level traditional villages in the Lingnan Region, which are analyzed with ArcGIS 10.8 and spatial analysis methods on the basis of the proximity index, geographic concentration index, kernel density estimation, and Geodetector. The aim is to reveal the spatial distribution patterns of traditional villages in the Lingnan Region and explore the mechanisms through which natural and socioeconomic factors affect their distribution. The results show that the spatial distribution of traditional villages in Lingnan is heterogeneous, with a certain degree of cohesion, and forms one high-density cluster and four secondary high-density clusters. The distribution is influenced by natural factors, such as climate, terrain, and river systems, as well as socioeconomic factors, such as intangible cultural heritage, population, and gross domestic product. However, the direction and magnitude of these influences vary. Among all the factors, temperature and intangible cultural heritage have the strongest explanatory power for the spatial distribution of traditional Lingnan villages. The combined influence of each factor with the other factors is greater than that of each factor alone. This research provides a scientific basis for the protection and development of traditional Lingnan villages.

Two retrofit strategies, aiming at increasing the collapse resistance of simple connections by adding seat angles and steel plates with long-slotted holes, are proposed in order to address the vulnerability of steel gravity frames under column loss scenarios. A high-fidelity, detailed, finite element model for a planar composite frame is developed and calibrated against experimental data and is used to conduct numerical analysis to explore the effectiveness of the proposed retrofit strategies. The simulation results show that the planar composite frame with enhanced connections exhibits significantly higher collapse resistance and better ductility under column loss scenarios compared with the one with conventional connections. Meanwhile, it is also revealed that the proposed retrofit strategies have an insignificant impact on the behavior of the structural system under earthquakes. These two retrofit strategies are then implemented to retrofit the gravity system of a 10-story, seismically designed steel frame structure, which has been shown to be vulnerable to progressive collapse after an interior gravity column is forcibly removed or impacted by a heavy vehicle with high speed. Numerical simulations were performed using a 3-D micro-based model and the simulation results illustrate that progressive collapse of the structure with enhanced gravity systems is prevented under both scenarios. Therefore, the proposed retrofit strategies are effective in preventing the progressive collapse of existing steel structures employing simple connections.

This paper investigates the collapse resistance of three-dimensional steel moment-resisting frame structures. Two static push-down analysis are conducted experimentally using 1/3 scale one-story steel frame structures. A bare steel frame structure without slab system is firstly tested to study its behavior subjected to loss of the interior column, following by a second experimental test on an identical frame with reinforced-concrete slab system under the same column loss scenario. The overall behavior and the failure modes of the two structures are recorded and compared. The contribution of the RC slab to the collapse resistance of the system is also explored. The test results show that both substructures exhibit remarkable robustness to prevent the occurrence of progressive collapse under column loss scenarios. The presence of the RC slab system can increase the initial stiffness and load carrying capacity of the structural system substantially.

Considering the disastrous consequences of the oil tank failure, it is of great importance to ensure the safety of the large‐scale oil tank under earthquakes. This study sheds light on investigating the dynamic response of a prototype 100,000 m³ cylindrical oil‐storage tank under various seismic excitations. The foundation of the tank is also considered in this study so that the obtained results are closer to the reality. Shaking table tests are conducted using a 1/20 scale liquid‐tank‐foundation system under various seismic excitations. The test results reveal that the dynamic responses such as accelerations and the deformation of the test specimen in the major and minor vibration directions do not differ significantly. Finite element models are constructed for the test specimen and the prototype tank and are validated through comparing the simulation results with the test data. The simulation results suggest that it might be necessary to stiffen the locations on the tank wall where the thickness of the tank wall changes because the stresses at such locations may be close or even exceed the yield strength of the structural steel under severe earthquakes.