This paper describes an experimental investigation into confinement effects provided by circular tubular sections to rubberised concrete materials under combined loading. The tests include specimens with 0%, 30% and 60% rubber replacement of mineral aggregates by volume. After describing the experimental arrangements and specimen details, the results of bending and eccentric compression tests are presented, together with complementary axial compression tests on stub-column samples. Tests on hollow steel specimens are also included for comparison purposes. Particular focus is given to assessing the confinement effects in the infill concrete as well as their influence on the axial–bending cross-section strength interaction. The results show that whilst the capacity is reduced with the increase in the rubber replacement ratio, an enhanced confinement action is obtained for high rubber content concrete compared with conventional materials. Test measurements by means of digital image correlation techniques show that the confinement in axial compression and the neutral axis position under combined loading depend on the rubber content. Analytical procedures for determining the capacity of rubberised concrete infilled cross-sections are also considered based on the test results as well as those from a collated database and then compared with available recommendations. Rubber content-dependent modification factors are proposed to provide more realistic representations of the axial and flexural cross-section capacities. The test results and observations are used, in conjunction with a number of analytical assessments, to highlight the main parameters influencing the behaviour and to propose simplified expressions for determining the cross-section strength under combined compression and bending.

本文描述了在组合载荷作用下，圆形管状截面对橡胶化混凝土材料的约束作用的实验研究。测试包括用0％，30％和60％橡胶代替矿物集料的样品（按体积计）。在描述了实验安排和试样细节之后，介绍了弯曲和偏心压缩试验的结果，以及对短柱样品进行补充轴向压缩试验的结果。为了比较目的，还包括对中空钢试样的测试。特别着重于评估填充混凝土中的约束作用及其对轴向弯曲截面强度相互作用的影响。结果表明，尽管容量随着橡胶替代率的增加而降低，与常规材料相比，对于高橡胶含量的混凝土，其约束作用得到了增强。通过数字图像相关技术进行的测试测量表明，在组合载荷下轴向压缩的限制和中性轴的位置取决于橡胶含量。还应根据测试结果以及整理后的数据库中的分析结果，来确定确定橡胶填充混凝土横截面容量的分析程序，然后将其与可用的建议进行比较。提出了与橡胶含量有关的改性因子，以提供对轴向和挠曲横截面容量的更真实的表示。将测试结果和观察结果与许多分析评估结合起来使用，