The hysteretic working capacity of reinforced masonry shear (RMS) walls has been estimated empirically and statistically referring to the structural ultimate state with considerable uncertainty. This investigation is to try to break this puzzlement of the uncertainty by revealing the hysteretic working features of RMS walls applying structural state-of-stress theory. The experimental residual strains are firstly modeled as generalized strain energy density (GSED) values (state variables) to describe structural state-of-stress mode and its characteristic parameter (GSED sum). Then, the slope increment criterion is proposed to detect the state-of-stress mutation point in the GSED sum-load curve. Accordingly, it is verified that the evolution of the state-of-stress mode presents the mutation feature. Thus, the starting point of the RMS wall’s failure process is revealed as the embodiment of the natural law from quantitative change to qualitative change of a system. And the hysteretic failure load of the RMS wall is defined at the state-of-stress mutation point with the attribute of certainty and generality. Furthermore, the GSED-based analysis reveals the working features between the state-of-stress submodes of structural components. This investigation explores a new way to analyze the hysteretic working behavior of RMS walls, which provides the rational reference to the accurate estimation of the failure loads of RMS walls for designs.

Nanoparticles leverage their unique nanoscale effects to optimize concrete performance through synergistic multi-mechanism interactions. Core mechanisms include micro-filling effects (graded pore filling, optimized pore structure), nucleation (promoting crystallization of hydration products, refining microstructure), chemical reactivity (e.g., pozzolanic reaction of nano-SiO₂, enhancing interfacial transition zones), and interfacial strengthening (improving ITZ structure and stress transfer). Common nanomaterials (e.g., nano-SiO₂, Al₂O₃, carbon nanotubes) significantly enhance concrete’s mechanical properties, durability, and functionalities (e.g., self-sensing, electromagnetic shielding). However, nano-modified concrete still faces challenges such as poor dispersion, high cost, and environmental/health risks. Future efforts should focus on multi-scale mechanism research, green low-cost synthesis processes, and intelligent composite systems development to advance the engineering applications pf nano-modified concrete.

To investigate the mechanical properties of graphene (G) and calcium silicate hydrate (C-S-H) composites in different directions, molecular dynamics (MD) simulations and experiments were used, and the effects of temperature, loading rate, and graphene defects were also investigated. The experimental results show that the addition of graphene can improve the flexural, compressive, and tensile strength of the composite. The results of molecular dynamics simulation show that the addition of graphene in x and z directions can enhance the tensile strength of G/C-S-H in three directions, while the addition of graphene in y direction can reduce the tensile strength of G/C-S-H. At the same time, the tensile strength of G/C-S-H decreases with the increase in temperature and increases with the increase in loading rate. Meanwhile, the mechanical properties of G/C-S-H can be improved using a certain concentration of monatomic vacancy defects, diatomic vacancy defects, and S-W defects.

The study of the long-term behavior of the prestressed continuous beam is vital for the design and the appliance of wood structures in engineering. In this study, long-term experiments were first conducted to determine the long-term creep behavior. Afterward, the prestress of the long-term beam was regulated to the initial state, and we carried out short-term flexural experiments to explore the effect of prestressing regulation. The influences of prestressed value and the number of prestressed steel wires on the mechanical properties of the continuous beam were investigated and discussed. The experimental results demonstrate that the creep reduced the stress in the steel wires, weakened the effect of prestressing, and increased the tensile stress at the bottom of the beam, which led to a reduction in the bearing capacity of the beam. The prestressing regulation could increase the moment arm, so the bearing capacity of the beam was improved.

An anchorage device is an integral part of the prestressed Glulam beams. Therefore, its rationality and practicability have significant effects on the mechanical performance of the prestressed beams. To investigate the impact of the anchorage devices on the bearing capacity and stiffness of the prestressed beams, this paper compared and analyzed four kinds of anchors in detail through the finite element software. The results showed that when the initial mid-span deflection was 5 mm, 10 mm, and 15 mm, the bearing capacity of prestressed beams with four anchorage devices was 80.37–177.24%, 93.56–182.51%, and 95.62–194.60% higher than that of ordinary Glulam beam, respectively. When the initial mid-span top prestresses were 1 MPa, 1.5 MPa, and 2 MPa, the bearing capacity of prestressed beams with four anchorage devices was 101.71–172.57%, 105.85–175.88%, and 109.64–180.87% higher than that of ordinary Glulam beam, respectively. In addition, based on the simulation results, the prestressed beam with the external anchorage had the highest bearing capacity and stiffness. The deformation capacity of the beam with boot anchorage was the largest. The stress distribution of the beam installed under beam anchorage was the most uniform, and the beam with slotted anchorage was easy to cause stress concentration at the notch. Finally, based on the outstanding performance of the external anchorage, it was selected to carry out one experiment, and the experimental result showed that the simulation could predict the damage model and load–deflection relationship of the prestressed beams well.

To study the effect of wood creep on the long-term performance of prestressed glulam continuous beams, a 180-day test was carried out on beams configured with different numbers of steel wires (2, 4, 6) and with different prestress values (0, 7, 14 kN). By investigating the stress loss of the steel wires in the beam and the change in the mid-span deflection over time, the factors influencing the creep of the continuous beam were analyzed. Three models were selected to fit the creep process of the test beams. Moreover, the creep deformation coefficient θ was introduced to reflect the influence of glulam creep on the deflection change in the test beams and to predict the total deflection of the beam within 50 years. The results showed that with increasing the number of steel wires and the prestress value on the beams, the total stress of the steel wires declined more and faster. Increasing the number of steel wires or decreasing the prestress force value could effectively restrain the change speed of the mid-span long-term deflection of the beam. Three models were compared, and the power-law equation was the most accurate. At familiar steel wire quantities and force levels, the θ value of the test beams within the design service life of 50 years was determined to be 1.28–2.29.