考虑荷载分布的多跨连续钢-再生混凝土组合板长期性能研究

TIME-DEPENDENT BEHAVIOR OF MULTI-SPAN CONTINUOUS STEEL-RAC COMPOSITE SLABS CONSIDERING THE LOADING DISTRIBUTION EFFECTS

  • 摘要: 为量化再生粗骨料掺入对多跨连续钢-混凝土组合板长期性能的影响,基于ABAQUS软件建立组合板的非线性热力耦合有限元模型,模型考虑非均匀收缩、非均匀徐变以及混凝土开裂的耦合影响;利用18组足尺试验数据验证模型的可靠性,并对现有规范方法的适用性进行评述;在此基础上,研究不同荷载分布下再生粗骨料取代率对五跨连续组合板长期性能(挠度及支座弯矩)的影响。研究结果表明:基于龄期调整的有效模量法,通过设置温度梯度模拟组合板中混凝土的非均匀收缩、非均匀徐变特性,可有效预测钢-再生混凝土组合板的长期性能,试件跨中挠度的有限元与试验结果最大相差20.3%;掺入再生粗骨料对多跨连续组合板长期性能的影响显著,且不同荷载分布下的影响规律相似,取代率为50%和100%时,组合板在均布荷载作用下的跨中挠度分别增加22.1%和45.0%,支座负弯矩分别增大5.3%和10.8%;与均布荷载作用相比,考虑非均布荷载的钢-再生混凝土组合板长期挠度和支座负弯矩均有所增大,幅值在10%以内。

     

    Abstract: To quantify the impact of recycled coarse aggregate (RCA) incorporation on the time-dependent behavior of multi-span continuous steel-RAC composite slabs, nonlinear thermal-mechanical finite element (FE) models were proposed based on ABAQUS, considering the combined effects of non-uniform shrinkage, non-uniform creep and concrete cracking. The proposed models were benchmarked against the long-term data from 18 full-scale composite slabs. The feasibility of current design procedures was also evaluated. Using the verified FE models, the influence of the RCA replacement ratio (r) on the time-dependent distributions was quantified. The results show that by specifying the temperature variation to simulate the non-uniform shrinkage and creep, the proposed FE models could well predict the time-dependent behavior of steel-RAC composite slabs based on the age-adjusted effective modulus method. The maximum error between the measured and calculated mid-span deflections was 20.3%. The time-dependent behavior of the composite slabs was remarkably influenced by the RAC incorporation. The influence magnitudes were similar for the composite slabs under different loading distributions. Under uniformly distributed loading, 22.1% and 45.0% increments in the mid-span deflection and 5.3% and 10.8% increments in the hogging moment were obtained for r ratios of 50% and 100%, respectively. The influence of the loading distribution on the mid-span deflection and hogging moment was within 10%.

     

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