中文摘要：

利用自制的内埋式混凝土应变计和通用有限元软件，对钢管混凝土桁梁试件受压弦杆管内填充混凝土的应变状态进行研究．试验研究结果表明，在单调加载条件下，自埋式混凝土应变计能准确测读受压弦杆管内混凝土的应变状态；混凝土应变随荷载增大呈双折线增长模式，桁梁试件破坏时混凝土受压应变达到5000με．当采用平面塑性梁单元对钢管混凝土桁梁进行整体分析时，不管弦杆受压还是受拉，管内混凝土均应考虑套箍效应；桁梁受压弦杆管内混凝土纵向应变有限元计算值与实测值吻合良好，桁梁试件破坏时混凝土应变处于高套箍状态．

英文摘要：

The strain state of concrete filled in compressive chord tube of concrete filled steel tubular （CFST） truss girder was investigated with self-prefabricated embedded strain gauges and test-verified finite element （FE） model. Experimental investigation reveals that the embedded strain gauges predict accurately the strain change of infilled concrete under monotonic loading, and that a bilinear increment curve with a maximum value of 5 000 με is measured for the concrete in compression. When plane plastic beam element model is used for FE analysis of CFST taken into account for concrete filled in both chords in infilled concrete along chord tube calculated by FE mod under highly confined state when truss girder specimen truss girder, the confinement effect should be compression and tension. Longitudinal strain of el agrees well with test value; concrete strain is fails.