聚氨酯-钢板夹层正交异性桥面板试验研究

EXPERIMENTAL RESEARCH ON ORTHOTROPIC BRIDGE DECK WITH STEEL PLATE-POLYURETHANE SANDWICH STRUCTURE

通过2个不同纵向加劲肋间距的聚氨酯-钢板夹层结构正交异性三跨连续桥面板的钢箱梁模型试验,结合有限元计算分析方法建立多种加劲肋间距桥面板的钢箱梁计算模型进行计算对比,研究该种桥面板的受力性能,试验模型按实桥同种材料的箱梁缩小1/4制作,按汽车荷载在跨中及支点截面产生最大弯矩时测试截面各关键点的纵向、横向应变和挠度。结果表明:桥面板各点应变试验值与计算值基本吻合;采用聚氨酯-钢板夹层结构正交异性桥面板可大幅削减局部应力集中峰值,从而可大幅减少加劲肋数量,减少程度主要取决于夹层板厚度;板面有些部位要同时承受两个正交方向的反号应力;相应截面中间加劲肋底部纵向应力最大;夹层桥面板的应力和挠度随着芯层厚度减小,增幅加大。

The mechanical properties of a 3-span continuous orthotropic bridge deck with a steel plate-polyurethane sandwich structure were investigated by means of steel box girder model experiments for the bridge decks with two kinds of longitudinal stiffener spacings and by comparing with calculation results of steel box girder finite element models for the bridge deck with various stiffener spacings. The test model was made of the same material as its actual bridge and the geometrical dimensions of the box girder were reduced to 1/4. The strains in the length and transverse ways, and deflections of the cross section at key points were tested, as a truckloading is generating the maximum bending moment at the midspan as well as on the cross section at the supports. The results show that： test strain values of the bridge deck are basically agreed well with the calculated values. Using the orthotropic bridge deck with a steel plate-polyurethane sandwich structure can greatly reduce the peak value of a local stress concentration and thereby greatly reduce the quantity of a stiffening rib, and the decrease mainly depends on the sandwich plate thickness. Some positions of a sandwich bridge deck will bear an opposite stress sign in the two orthogonal directions, the maximum longitudinal stress is at the bottom of a middle stiffener in a corresponding cross-section. The stress and deflection growth of a sandwich bridge deck will increase with the decrease of its sandwich layer thickness.