The impermeability of concrete is very important to its durability and service life, which could be affected by nanomaterial and mineral admixture additions. This paper tends to enhance the impermeability, strength, and microstructure of concrete using nano-silica (NS) and U-type expansive agent (UEA). The slump flow, compressive strength, chloride ion resistance, water penetration and absorption, hydration, and microstructure of concrete are investigated under different NS and UEA contents. The results indicate that an appropriate NS content of 2% contributes to dense pore structure and the generation of more hydration product for impermeability-enhanced concrete, which results in a compressive strength of 43.53 MPa and chloride ion and water penetration resistance improvements of 21% and 35%, respectively. The slump flow and compressive strength of concrete decrease slightly in the presence of UEA utilization, while the chloride ion and water penetration resistances are firstly enhanced and then weakened with the increase in UEA contents. In the case of 9% UEA, the concrete achieves a compressive strength of 31.54 MPa, a chloride ion penetration coefficient of 9.34 × 10⁻¹² m²/s, and a relative permeability coefficient of 2.56 cm/s.

The application of round-ended rectangular concrete-filled steel tubes (RRCFSTs) in high-rise buildings or bridge structures is increasing, improving structural performance and meeting aesthetic requirements. Researching this novel steel–concrete composite helps to fully utilize the properties of the materials. In this study, 15 specimens were tested for analysis of the behaviors of RRCFSTs with different central angles under eccentric compression. Influences of central angles of round ends (θ), aspect ratios of rectangular parts (κ), steel strength and the eccentric ratio on failure modes, material utilization, confinement effect and eccentric bearing capacity are studied. Besides, the mechanism of confinement effects of steel tubes with different θ values was evaluated with the finite element method (FEM). The results show that local buckling usually occurs at the compression zone. When θ gradually changes from 0° to 180°, the local buckling position of straight steel plate changes from mid-length to both ends of the columns. Additionally, the interfacial stress between steel tube and concrete at round ends rises, but that at the corner, it decreases continuously, which results in an improved overall confinement effect and increased material utilization. In contrast, a larger κ leads to lower material efficiency because of the reduced overall confinement effect. The increases in both θ and κ enlarge the cross-sectional area and the eccentric ultimate bearing capacity, whereas θ has a better influence on the ductility than κ. A feasible simplified calculating approach for the eccentric ultimate bearing capacity of RRCFSTs is presented and validated.

The carbon-neutral transition and the digital transformation of the construction sector are increasing the demand for low-carbon, high-efficiency equipment systems for super-high-rise building construction. Conventional heavy-duty integrated platforms often rely on massive support systems, extensive steel consumption, manual inspection, and limited closed-loop digital feedback, which restrict their adaptability to irregular core-tube layouts and variable construction conditions. This study develops and validates a lightweight intelligent aerial construction machine for super-high-rise building construction. The proposed system integrates a multi-point small-stroke electro-hydraulic synchronous lifting system, a detachable “Bailey frame + steel truss” steel platform, modular prefabricated installation, and a digital-twin-based operation and maintenance platform. Engineering validation was conducted using representative floor-cycle data and real project applications at the Meituan Shanghai Technology Center and Wuhan Taikang Financial Center. Compared with a conventional heavy-duty integrated platform, the weight of a single support column was reduced from 30 t to 5 t, steel platform consumption decreased from 0.5 t/m² to 0.2 t/m², and total equipment weight decreased from approximately 900 t to 230 t. Representative floor-cycle records show that jacking duration was reduced by more than 50%, while modular installation shortened the installation period from 45 days to 25 days and increased the component turnover rate from about 30% to over 80%. These results indicate that lightweight structural design, intelligent synchronous lifting, and modular assembly can jointly improve safety, adaptability, and resource efficiency in super-high-rise building construction.

Efficient reuse of Building Information Modeling (BIM) components is essential for construction detailing. However, reusable resources are frequently dispersed across project files and conventional folder-based repositories. This fragmentation increases retrieval effort and repetitive modeling. This study develops a Revit-based platform that transforms dispersed component resources into a structured and reusable component library within the native Revit environment. The platform integrates component archiving, hierarchical classification, metadata-indexed retrieval, and rapid loading and placement. It also supports offline library sharing and synchronization, quantity statistics, and completeness verification. A unified component data model supports both individual Revit families and multi-element assemblies and connects resource archiving, retrieval, reuse, sharing, and post-use verification into a continuous management–reuse–verification workflow. The platform was evaluated using Bailey trusses and other construction components from a building construction-machine project. A randomized, counterbalanced within-participant experiment involving 12 engineering technicians showed that the platform reduced mean task-completion time from 299.5 s to 87.3 s, representing a 70.9% reduction and an approximately 3.43-fold increase in modeling efficiency. A paired-samples t-test confirmed a statistically significant difference between the two workflows (t(11) = 71.03, p < 0.001). Retrieval tests further demonstrated strong scalability: as the library size increased twentyfold from 50 to 1000 components, platform retrieval time increased from 5 s to 19 s, whereas conventional folder-based retrieval increased from 35 s to 769 s. At 1000 components, the proposed platform was approximately 40.5 times faster. Within the evaluated Revit 2020 tasks and library sizes, these findings support an integrated approach to improving component retrieval and repetitive modeling efficiency; broader validation remains necessary.