CFRP-圆钢管混凝土柱偏压试验研究

通过对16根CFRP-圆钢管混凝土偏压柱试验为基础,研究CFRP-圆钢管混凝土偏压柱的受力性能,分析了偏压柱承载力的主要影响因素长细比和偏心率对CFRP-圆钢管混凝土偏压柱承载力的影响.钢管和CFRP可以保持协同工作.     

服役斜拉索疲劳状态的全场域在线实时监测与智慧感知

为了能对斜拉桥拉索的服役性能进行更为准确和及时的评估,提出了一套服役期拉索疲劳状态评估的全场域实时监测与智慧感知技术方案。该方案首先给出了基于拉索横向动刚度分析理论的拉索全场域、全应力时程的实时感知方法,其次利用Miner线性疲劳累计损伤理论评估拉索全场域的疲劳损伤状态;最后,将其应用于一座斜拉桥的拉索的振动监测信息处理上,证明了所建议的技术和方案可实现服役拉索疲劳状态的全场域实时监测和智慧感知。具体结论如下:在拉索疲劳应力幅的组成中,由外荷载引起的索端位移产生的索力变化所产生的应力占比最大,当拉索发生较大幅度振动时,振动附加索力变化产生的应力也不可忽略;通过对拉索疲劳应力幅的统计分析发现,与长索相比,短索对外荷载更加敏感,通常会引起更大和更频繁的索力变化,故在斜拉桥拉索疲劳分析中,应对短索给予更多的关注;在拉索疲劳损伤分析时,弯曲应力和腐蚀的影响非常显著,若要使拉索疲劳寿命的预测更接近实际工程情况,需要考虑弯曲应力和腐蚀的影响;在应力幅较大的区域,对应循环次数较少,但拉索疲劳损伤度较大,在应力幅较小的区域,虽然循环次数较多,但拉索的疲劳损伤度较小,所以,在疲劳分析中,拉索应力幅比循环次数更值得关注。     

局部锈蚀下Q550E钢梁抗弯性能试验研究

侵蚀环境下高性能钢结构普遍存在局部锈蚀病害，这将削弱结构的整体承载能力。为了研究局部锈蚀对钢结构承载力的影响程度，设计制作了7片H形Q550E高性能钢梁，研究不同局部锈蚀对高性能钢梁抗弯性能的影响。首先对其中6片试验梁的弯剪段和纯弯段开展了不同锈蚀率的加速锈蚀，另1片为未锈蚀对比梁。接着，对试验梁开展四点弯曲分级加载试验，采集并对比分析了试验梁关键截面的应变和挠度数据。结果表明：锈蚀导致试验梁的承载力、屈服挠度、极限挠度和延性降低，相同锈蚀率下纯弯段性能降低程度大于弯剪段；右半截面承载力比下半截面降低程度更大；所有试验梁均为受压翼缘屈曲失稳破坏；SCR梁屈曲发生在弯剪段，其他试验梁屈曲位置位于纯弯段；弹性阶段腹板应变符合平截面假定，试验梁受拉翼缘一般先于受压翼缘屈服，因此随着荷载的增加，会出现截面中性轴上移现象；整体锈蚀比纯弯段下半截面锈蚀时的剩余承载力低，主要因为整体锈蚀时受压翼缘存在锈蚀削弱，导致试验梁屈曲提前，承载力降低；局部锈蚀的不均匀性会产生翼缘应力集中，导致PCR试验梁比整体锈蚀梁承载力低；与普通钢梁相比，锈蚀对于高性能钢梁承载力退化影响更大；对于顶板和底板锈蚀，梁的剩余承载力与其锈蚀程度为线性关系。     

Vertical and horizontal bending moments on the hydroelastic response of a large-scale segmented model in a seaway

Wave-induced vertical bending moment (VBM) and horizontal bending moment (HBM) on a large-scale segmented model with a box-type backbone beam in short-crested irregular seas are systematically analyzed using sea trial measurement data. New insights into the relationship between nonlinear VBM and HBM of the ship sailing in short-crested sea waves are explored and presented. The results indicate that the HBM significantly contributes to the total sectional loads when the ship is sailing in a seaway and the HBM has a strong correlation with VBM in both magnitude and tendency. Therefore, design loads of HBM and the corresponding lateral structural strength issues should also be concerned in addition to VBM at the ship design phase.     

Investigation on the nonlinear effects of the vertical motions and vertical bending moment for a wave-piercing tumblehome vessel based on a hydro-elastic segmented model test

Although the nonlinear effects of the ship motions, wave-induced loads and structural responses of conventional vessels have been investigated experimentally and numerically in recent years, similar studies on the wave-piercing tumblehome (WPTH) vessels are rare, in spite of the urgent necessary due to their extensive applications. This paper experimentally investigated the nonlinear effects of the vertical motions and vertical bending moment (VBM) for a WPTH vessel based on a hydro-elastic segmented model test. The model test was carried out in head regular waves for three amplitudes, in the towing tank at Harbin Engineering University. Based on the band-pass filter technique, four kinds of decomposed harmonics are defined by mean offset, linear wave-frequency response, nonlinear wave-frequency response and nonlinear high-frequency vibration. Meanwhile, based on mean offset, three kinds of combined responses are defined by considering linear wave-frequency response, nonlinear wave-frequency response and nonlinear high-frequency vibrations step by step. The transfer functions of vertical motions and VBM are presented as function of the incident wave frequency, and the measured data and VBM were compared with numerical calculations for validation. With the method proposed above, the results of VBM are analyzed by focusing on the influences of decomposed harmonics on the amplitudes and asymmetry of combined responses. Strong nonlinear effects are observed in the VBM. The nonlinearity of VBM can be identified by the significant amplitudes of decomposed harmonics, variation of amplitude with the wave amplitude and remarkable asymmetry about the zero axis. The hogging VBM of WPTH vessel can be even larger than the sagging VBM, which is in contrast to the general experiences from conventional vessels. Combined the calculated relative motion with the decomposed and combined histories of VBM, the occurrence of the transient impact and its characteristics are discussed, and these are then used to analyze the unconventional asymmetry of VBM. Furthermore, the influences of the bow shape over the vertical motions and VBM are discussed. At the end of the paper, the uncertainties in the test are provided.     

编织网增强混凝土受弯性能及电阻稳定性研究

为了实现融雪化冰系统的智能控制,通过四点弯曲试验研究了不同表面处理的碳／玻璃纤维混合编织网增强混凝土薄板的受弯性能以及纤维束电阻值的变化情况。试验结果表明：环氧树脂浸渍以及粘砂处理纤维编织网的方式可有效提高薄板的承载能力;在荷载作用下,纤维束的电阻值稳定,不同表面处理方式不会对电阻的稳定性产生影响。     

排洪明槽底板按弹性地基基础梁进行的受力分析

在遵崇高速公路一填筑路基上设置的U型大断面排洪明槽结构设计中,将其底板按弹性半无限平面上的基础梁（属共同变形理论）进行受力分析,计算出地基反力、梁截面内力（剪力、弯矩）作为梁设计的依据。介绍了该方法计算的理论和步骤,并与假定地基反力按直线分布的计算结果进行了比较,显示出共同变形理论计算的合理性。排洪明槽经数年使用,完好无损。     

钢-混凝土组合连续梁桥负弯矩区施工控制研究

该文以深圳市机场南路新建工程(50+82+50)m钢-混凝土组合连续梁桥为例,对钢-混凝土组合梁负弯矩区施工控制方法进行分析研究。研究结论可供同类工程参考。     

不同交联度环氧沥青混合料低温弯曲性能研究

环氧沥青作为一种交联的粘弹性材料,其低温力学性能受交联密度影响较大。该文介绍了其低温弯曲性能试验研究。采用交联度75.3%、71.4%、67.3%和58.4%的环氧沥青混合料,进行-20℃、-10℃、0℃、10℃温度下小梁三点弯曲性能试验。结果表明,不同交联度的环氧沥青混合料弯曲强度与模量随着温度的提高而降低,破坏变形与应变能密度随着温度的提高而增大。不同交联度的环氧沥青混合料弯曲强度、模量、破坏变形及应变能密度与温度关系基本一致,各弯曲性能参数的温度敏感区间也基本相同,交联度75.3%混合料的弯曲性能参数温度敏感区间为大于10℃,交联度71.4%和67.3%的温度敏感区间为0~10℃,交联度58.4%温度敏感区间为-10~0℃;温度敏感区间弯曲性能参数变化幅度较大,低于温度敏感区间,则弯曲性能参数变化幅度较小。环氧沥青混合料低温弯曲性能参数与温度、交联度之间具有较好相关性,可以建立混合料弯曲强度、模量、破坏变形及应变能密度与温度、交联度的关系,并用于混合料低温弯曲性能预测。