This study aims to investigate the bending load-bearing capacity of precast hollow composite slabs composed of ultra-high-performance concrete (UHPC) and Normal Concrete (NC). Through finite element numerical analysis and verification, this study analyzes various key factors influencing the performance of the composite slab, including the wall thickness of the square steel tube, the diameter of transverse reinforcing bars, the thickness of the precast bottom slab, and the strength grade of the concrete. The results indicate that the use of UHPC significantly enhances the bending performance of the composite slab. As the wall thickness of the square steel tube and the strength of UHPC increase, both the yield load and ultimate load capacity of the composite slab show considerable improvement. By conducting an in-depth analysis, this study identifies different stages of the composite slab during the loading process, including the cracking stage, yielding stage, and ultimate stage, thereby providing important foundations for optimizing structural design. Furthermore, a set of bending load-bearing capacity calculation formulas applicable to UHPC-NC precast hollow composite slabs is proposed, offering practical tools and theoretical support for engineering design and analysis. The innovation of this study lies not only in providing a profound understanding of the application of composite materials in architectural design but also in offering feasible solutions to the energy efficiency and safety challenges faced by the construction industry in the future. This research demonstrates the tremendous potential of ultra-high-performance concrete and its combinations in modern architecture, contributing to the sustainable development of construction technology.

This paper proposes a method for modifying brick masonry walls using ultra-high-performance concrete (UHPC) to effectively reduce the beam section width in composite members. First, a detailed finite element model of UHPC–brick masonry composite beams was established using the finite element software ABAQUS 2022 and validated through comparison with the existing literature. Then, the effects of factors such as the tensile reinforcement ratio, UHPC layer thickness, and UHPC strength grade on the load–midspan deflection curve of composite members were analyzed, along with a study of the bending performance under vertical loads. Based on the results of the finite element analysis, a calculation formula for the positive section bending capacity of UHPC–brick masonry composite beams was proposed. The study found that longitudinal tensile reinforcement yielded first, followed by the crushing of the compressive region of UHPC and brick masonry, resulting in overall bending failure. With the increase in the tensile reinforcement ratio and UHPC layer thickness, both the yield load and peak load significantly increased, while the UHPC layer thickness had a notable impact on the cracking load of the composite member. When the UHPC strength grade ranged from 150 MPa to 180 MPa, the bearing capacity of the composite member changed little. The proposed calculation method for bearing capacity correlated well with the finite element results, providing a theoretical basis for the design and analysis of UHPC–brick masonry composite beams.