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

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。

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,nonuniform 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%.