The steel tube slab (STS) structure is a novel pipe-roofing structure, which is used as the support system for underground stations. The pipe-roofing structure is generally assumed as a beam structure in previous research, which is questionable, because the transverse and longitudinal coupling force mechanism is ignored. Hence, this work aims to investigate the flexural performance of STS composite slab through experimental test and establish a design approach for STS structure. Firstly, based on six tests on flexural performance of the STS composite slabs, the crack development, failure mode and deformation mechanism were analysed. Each of the specimens demonstrated a high bearing capacity that exceeded 3000 kN. Furthermore, the specimens exhibited ductility during testing with the failure occurring at either the flange or concrete between the steel tubes. Subsequently, the effect of the length–width ratio and spacing between the tubes on the flexural performance of the tested specimens were examined. The result indicated that the length–width ratio and the spacing between the tubes significantly affected the flexural stiffness, but had limited effects on the flexural capacity. Finally, a design approach was proposed to estimate the elastic capacity of STS composite slabs, and finite element (FE) models validated by the test results were established to increase the general applicability of the theoretical model. The predicted outcomes demonstrated a satisfactory correlation with both the test and FE results, with an average relative error of 9.8%. The study's findings are anticipated to serve as a dependable resource for the design and application of STS structures.

钢管板（STS）结构是一种新型管屋盖结构，用于地下车站的支撑体系。以往的研究普遍将管屋结构假设为梁结构，这是有问题的，因为忽略了横向和纵向的耦合力机制。因此，本工作旨在通过实验测试研究STS复合板的弯曲性能，并建立STS结构的设计方法。首先，通过对STS复合板的六次弯曲性能试验，分析了裂纹的发展、破坏模式和变形机制。每个样本均表现出超过 3000 kN 的高承载能力。此外，测试期间，样本表现出延展性，失效发生在钢管之间的法兰或混凝土处。随后，研究了长宽比和管间距对测试样本弯曲性能的影响。结果表明，长宽比和管间距对弯曲刚度影响显着，但对弯曲承载力影响有限。最后，提出了一种估计STS复合板弹性能力的设计方法，并建立了经试验结果验证的有限元（FE）模型，以提高理论模型的普遍适用性。预测结果与测试和有限元结果具有令人满意的相关性，平均相对误差为 9.8%。