The temperature shrinkage effect is a very important factor causing the cracking of super-long frame structures. Current design codes and recommendations for reinforced concrete (RC) structures consider the influence of the construction process on the temperature shrinkage effect by adopting a uniform reduction coefficient and neglect the influence of the construction method. However, different construction processes can vary the temperature stress of the structure. In this paper, under cooling action, the temperature stress of a one-layer, super-long frame structure with different quantities and indwelling times of post-cast strips is calculated with a spatial nonlinear simulation analysis program by adopting the degenerated spatial solid virtual laminated element method. With this approach, the internal force state of each construction stage during the construction process is accounted for in a nonlinear mechanical model of the structure. The results show that the quantity and the indwelling time of post-cast strips can effectively vary the temperature stress of the structure. Meanwhile, the quantity of the post-cast strips can have a more obvious effect than the indwelling time. Therefore, the construction process is an important factor affecting the temperature shrinkage effect of the structures. The research results can provide a valid reference for the design and construction of super-long frame structures.

The region of the RC slab–column connection is subject to complex forces and is susceptible to localized damage, leading to progressive collapse incidents, which has raised considerable concern among the engineering community. At present, the research on slab–column connections exhibits several shortcomings, including a limited number of specimens, incomplete consideration of various factors, and unclear boundaries in defining failure modes. A comprehensive consideration of the punch–span ratio (a/h₀) and longitudinal reinforcement eigenvalues (ρƒ_y/ƒ_c) is lacking, and the calculation formula for load bearing is not subdivided based on distinct failure modes. In this study, finite element software is utilized to construct 42 models of slab–column connections. The variables considered encompass three factors: the punch–span ratio, the longitudinal reinforcement ratio, and concrete strength. The examination and evaluation encompass the analysis of the load–displacement curve, reinforcement stress change curve, section crack distribution pattern, and stress contour map obtained through model loading. The primary parameters defining the boundaries of the three failure modes in the slab–column connection are the punch–span ratio and longitudinal reinforcement eigenvalues. Utilizing the punch–span ratio and longitudinal reinforcement eigenvalues as key parameters, a punching and flexural failure model for slab–column connections without abdominal bars is formulated. The calculation formula for bearing capacity, encompassing flexural, flexural and punching, and punching shear failure, is derived. A comparison between the revised formula and the standard formulas from major countries indicates that the revised formula is more comprehensive, providing a more accurate and secure prediction within the scope of this study.

In this paper, a novel T-shaped steel–concrete composite shear wall (TSCCW) is proposed. Low-cycle reciprocating tests were carried out on the TSCCW to investigate its performance in terms of its damage characteristics, hysteretic properties, energy dissipation capacity, stiffness degradation and ductility. A numerical model was established on the basis of the tests, and the correctness of the numerical model was verified. Afterwards, parameters such as shear span ratio, axial load ratio, rebar diameter, steel thickness, concrete strength grade and axial compression position were analyzed. The results show that the shear span ratio has a great influence on the performance of the TSCCW. A reduction in the shear span ratio from 2.1 to 1 reduces its stiffness by 333%. An increase in the axial load ratio will increase the load carrying capacity and stiffness of the TSCCW, and the deformation capacity will first increase and then decrease; it is recommended that the axial load ratio should be taken as 0.4. Increasing the steel thickness will improve the load carrying capacity, stiffness, deformation capacity and energy dissipation capacity of the TSCCW to a certain extent. Increasing the reinforcement diameter has less effect on the seismic performance of the TSCCW.

Temperature stress analysis is of prime importance to ensure the adequate servicing of super-long frame structures during their service life. The existing design codes and recommendations for reinforced concrete (RC) structures provide methodologies for the reinforcement of design elements that neglect differences in the linear expansion coefficients of steel and concrete. In this paper, we present a numerical method based on a degenerated three-dimensional solid virtual laminated element for simulating and analyzing the temperature stress of a two-layer super-long frame reinforced concrete structure subjected to allover cooling action, whereby the difference in the linear expansion coefficients of steel and concrete are taken into consideration. The results show that the difference in the linear expansion coefficients of steel and concrete, with different constraints, affects the temperature stress experienced by each material in the structure, and this difference adversely affects attempts to avoid structure cracking.