With the continuous improvement of building energy-conservation requirements, both traditional concrete external insulation and internal insulation have been unable to meet energy-saving needs. In order to meet the demands of building energy-saving in the new era, new precast concrete external-wall-insulation technology should be developed. In this study, a bending static test and numerical simulation were carried out to evaluate the influence of the thickness of inner concrete wythe and insulation and the length of plate-type shear connectors on the cracking condition, bearing capacity and composite degree of a precast ceramsite-concrete-insulated sandwich panel (PCCISP) under the outside-plane load. The results show that the failure modes of four precast ceramsite-concrete-insulated sandwich panels were all ductile failure of the concrete flexural members. The ultimate bearing capacity of the PCCISP decreased with the decrease in the thickness of the inner concrete wythe. Reducing the thickness of insulation had no significant influence on the ultimate bearing capacity. When the thickness of insulation was reduced by 30%, the composite degree of rigidity and bearing capacity of the PCCISP were increased by 8.85% and 2.67%, respectively. Increasing the length of the plate-type shear connector slightly increased the ultimate bearing capacity, but it had no obvious influence on the rigidity and bearing capacity composite degree.

To assist in addressing the problem where an aluminum alloy formwork (AAF) deforms more greatly under the action of lateral pressure and therefore does not meet the requirements of plaster-free engineering, we propose a method for determining the geometric parameters of this formwork based on a PSO algorithm and BP neural network with ABAQUS as the platform. The influence of six geometric parameters of the formwork on the maximum deflection value of the panel under the action of lateral pressure is studied using finite element analysis. The maximum deflection value of the panel is used as the index, and the influence of each factor is analyzed with an orthogonal test, and a set of optimal geometric parameters is obtained via extreme difference analysis and analysis of variance. The sample data are obtained via finite element simulation, and the PSO-BP neural network model is established using the six factors of the orthogonal test as input values and the maximum deflection of the panel as the output value, and the optimal geometric parameters are optimized using the PSO algorithm. The results indicate that the maximum deflection for the panel in the orthogonal scheme is 1.446 mm. The PSO-BP neural network prediction model demonstrates greater accuracy and a 31.74% reduction in running time compared to the BP neural network prediction model. The optimized PSO-BP neural network prediction model scheme reveals a maximum panel deflection of 1.296 mm, a 10.37% decrease compared to the orthogonal solution. These findings offer technical guidance and a foundation for optimizing AAF designs, presenting practical applications.

Current research on the evaporation inhibition effect of polyethylene (PE) floats has been relatively comprehensive, and the cost is relatively high when it is arranged in remote mountainous areas. In order to find a more economical anti-evaporation material, five kinds of solid expanded polystyrene (EPS) floating balls with different diameters of 10 mm, 40 mm, 80 mm, 120 mm and 150 mm were selected to study the evaporation suppression efficiency (ESE) of EPS floating balls on the evaporation of reservoir water surfaces in arid areas. The outdoor evaporator test and the wind wave test in the reservoir area were carried out. Combined with various meteorological data, the evaporation inhibition rates of EPS floating balls with different diameters during a non-freezing period were calculated. The durability, seepage prevention, wind resistance, frost resistance, aging resistance and other properties of EPS were observed under different climatic conditions. In the evaporator test, the relationship between the diameter of the floating balls and the ESE was not a single function. The ESE of floating balls with a diameter of 40 mm was the highest, at 76.31%. In the wind wave test in the reservoir area, the ESE of the 10 mm floating balls was the lowest, at 34.79%, and the ESEs of the other four diameters of EPS floating balls were above 85% and positively related to the diameter of the floating balls. The test further improved the selection scheme for the diameter of the anti-evaporation floating balls, provided a reference for the practical application of EPS floating balls in future water-saving projects in the reservoir area, and enriched the content of water-saving projects for plain reservoirs in arid areas.