综合管廊新型带肋超高性能混凝土板的抗弯性能

Flexural Performance of UHPC Plate with Ribs in Comprehensive Utility Tunnel

摘要:

针对预制拼装钢筋混凝土箱型管廊存在多舱化、自重大及易开裂渗水等问题，提出了一种带肋超高性能混凝 土（UHPC）管廊结构。通过矩形、梯形和平板3种截面形式及不同肋高的UHPC板静载试验，分析了配筋率、肋高宽比、钢筋与UHPC强度等参数对构件抗弯性能的影响。结果表明，构件均为少筋破坏，钢筋已屈服而UHPC抗压性能未充分发挥；等材料用量下，矩形肋板承载力和刚度显著高于梯形肋板和平板，肋高增加50 mm可提升承载力约20%；提高配筋率、肋高、钢筋强度和UHPC抗拉强度均可有效提升带肋UHPC板的承载性能，其中使用屈服强度超过785 MPa的受力钢筋或超过2.5%的配筋率可使带肋板破坏模式转为适筋破坏。

Abstract:

To address issues such as multi-compartment design， heavy self-weight， and susceptibility to cracking and water leakage in prefabricated assembled reinforced concrete （RC） box utility tunnels， this paper proposes a ribbed ultra-high performance concrete （UHPC） utility tunnel structure. Static loading tests were conducted on UHPC plates with three different cross-sectional shapes， rectangular， trapezoidal， and flat， with varying rib heights， to analyze the effects of parameters such as reinforcement ratio， rib height-to-width ratio， steel strength， and UHPC compressive and tensile strengths on the flexural behavior of the components. The results indicate that all specimens exhibit under-reinforced failure， with the steel reinforcement yielding while the compressive capacity of the UHPC is fully utilized. Under the same material usage， the rectangular ribbed plate demonstrates significantly higher load-bearing capacity and stiffness than the trapezoidal ribbed and flat plates. A 50 mm increase in rib height improved the load-bearing capacity by approximately 20%. Increasing the reinforcement ratio， rib height， steel strength， and UHPC tensile strength effectively enhances the load-bearing performance of the ribbed UHPC plates. In particular， using steel reinforcement with a yield strength exceeding 785 MPa or a reinforcement ratio above 2.5% cause the failure mode to shift from under-reinforced to an appropriately reinforced mode.