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| 大跨度预应力混凝土钢管桁架预制底板模拟施工荷载下力学性能研究 |
| Research on the Mechanical Behavior of Large-span Prestressed Concrete Steel-tube Truss Precast Slabs Under Simulated Construction Loads |
| 投稿时间：2025-12-26 修订日期：2026-02-04 |
| DOI： |
| 中文关键词: 钢管桁架 预制底板 力学性能 参数化分析 开裂荷载计算 |
| 英文关键词: steel-tube truss precast slab mechanical property parameter analysis cracking load calculation |
| 基金项目:高校学科(专业)带头人培育项目(DTR2023028)；中国建筑国际科技研发项目(CSCI-2023-Z-11-2)；安徽省自然科学基金(19080885ME173) |
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| 中文摘要: |
| 大跨度预应力混凝土钢管桁架预制底板是一种新型混凝土叠合板中的底板形式。为研究不同尺寸预应力混凝土钢管桁架预制底板在浇筑过程中的力学性能，制作4块预制底板试件。同时为简化试验设计，采用多点分级静力加载模拟施工荷载，通过试验分析不同预制底板的开裂荷载、跨中挠度、裂缝分布、混凝土及钢管应变等结构性能的变化规律。结果表明:所有试件腹筋均未屈服，钢管桁架未脱出预应力混凝土底板，两者协同工作性能良好；预制底板底部跨中处首先开裂，裂缝沿跨中两侧均匀分布；开裂荷载对应的挠度均小于规范限值1/200l，满足混凝土浇筑时不设置临时支撑的要求。数值模拟极限承载力与试验值的误差均小于10%，受力变形特征和应力分布与试验吻合。关键参数化分析得出，桁架与灌浆料的存在能够大幅提升预制底板的承载能力，同直径下钢筋桁架比钢管桁架预制底板承载力高，但板底开裂损伤更严重；增加钢管数量与桁架高度可显著提升试件整体刚度与承载力。此外，以试验数据为基础，进行了钢管桁架预应力混凝土预制底板的开裂荷载计算，最终误差为3%~6%，验算结果良好。以上为预应力混凝土钢管桁架预制底板实际工程设计提供了普适性参考，同时为进一步研究更为复杂的荷载施加过程奠定基础。 |
| 英文摘要: |
| The large-span prestressed concrete steel-tube truss precast slab is a new type of slab form in the concrete composite precast slabs. To study the mechanical behavior of prestressed concrete steel-tube truss precast slabs during concrete pouring, four specimens of different dimensions were tested under multi-point staged static loading to simulate uniformly distributed loads. The cracking load, mid-span deflection, crack distribution, and strain in concrete and steel tubes were analyzed. The results indicate that none of the web reinforcement yielded, and the steel-tube trusses remained well bonded to the prestressed concrete slabs, exhibiting good composite action. Initial cracking occurred at the mid-span bottom of each slab, with cracks uniformly distributed along both sides of the span. The deflection corresponding to the cracking load in all specimens was below the code-specified limit of 1/200l, meeting the requirement for construction without temporary supports during concrete pouring. Numerical simulations showed good agreement with experimental results, with ultimate load prediction errors within 10%, and consistent deformation and stress distribution patterns. Parametric analysis revealed that the inclusion of steel-tube trusses and grouting significantly enhanced the load-bearing capacity of the slabs. Compared to steel-tube trusses, steel bar trusses provided higher capacity under the same diameter, but exhibited more severe cracking at the slab bottom. Increasing the number of steel tubes and the truss height markedly improved both stiffness and load capacity. Additionally, the cracking load of prestressed concrete steel-tube truss precast slabs was calculated based on test data, with prediction errors ranging from 3% to 6%, yielding satisfactory results. These findings provide a foundation for the application and development of such slabs in construction-stage performance evaluation. |
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