为研究预应力混凝土T梁在火灾后承载能力随延火时间的变化规律,采用ANSYS建立实体模型,通过施加不同的火灾工况,设计材料在高温下的强度折减,计算不同火灾工况下的抗弯承载力并对其安全性进行评估.结果表明,T梁在桥面受火时承载能力衰减程度低,承载力满足要求;T梁腹板底部及多面受火时,承载能力衰减速率先迅速后缓慢,在一段时间后均不满足要求.

为研究中国高等级沥青路面中常用的半刚性基层结构承载力评价方法,采用ABAQUS软件建立半刚性基层沥青路面结构模型,进行半刚性基层受力特点分析和功能分析.同时,分析了半刚性基层模量衰减对路面结构受力的影响.在大修路段进行FWD试验,反算半刚性基层模量,与该路段初始反算模量比较,计算大修路段半刚性基层模量衰减度.结合力学计算和实测结果,建立了基于模量衰减度评价半刚性基层结构损伤程度的方法.

The analysis of time invariant reliability is a prerequisite for determining the carrying capaci-ty of the bridge as well as the actual operating condition,and it is the basis of varying reliability calcu-lation.Taking a 20m T-beam bridge as example,the invariant reliability study of reinforced concrete T-beam bridge is carried out in this paper,the limit state equation of the reinforced concrete bridge is established,the probabilistic distribution of variable is analyzed,and the time invariant reliability is obtained,which can provide a reference for the assessment of bridge operating state.

Based on the preferred material,high-elastic and high-viscous rubber modified asphalt is prepared,its material properties are tested and the performance characteristics are studied in the pa-per.OGFC mixture is prepared with high-elastic and high-viscous asphalt,high-viscous asphalt,TPS modified asphalt respectively,and their road performance are compared.The results showed that:high-elastic and high-viscous rubber modified asphalt mixture has excellent water stability,high tem-perature stability.

为了确定聚丙烯纤维微表处混合料的最佳配合比设计,通过湿轮磨耗试验、负荷轮粘砂试验、拌合试验和低温弯曲试验等,确定了纤维掺量和最佳油石比,并对微表处混合料进行肯塔堡飞散试验及车辙试验研究,结果表明在微表处中加入纤维可以有效提高混合料的路用性能.

The commonly used two methods of slope stability evaluation are interpreted. Using finite element strength reduction method,the high slope stability which is excavated stepwise is analyzed. It is found that the safety factors increase after it is excavated stepwise. The first four class platforms after excavation show that the safety factors increase slowly by 0. 02 at most,but after the last class platform is excavated,the safety factors increase sharply by 0. 04. Also,the slip zone' s position basically remains unchanged after the first four class platforms ' excavation, while the slip zone's position changes obviously after the last two class platforms ' excavation. Finally, the safety factors calculated by GEO-SLOPE is similar to that calculated by the finite element strength reduction method. The results show the application of the finite element strength reduction method is reasonable.

为了研究增大截面法加固钢筋混凝土偏心受压构件的正截面承载力,采用围套加固法和双侧加固法对不同截面尺寸的偏心受压构件进行承载力试验.应用ABAQUS软件对钢筋混凝土偏压构件的加载过程进行模拟.将实测结果、有限元计算结果与加固规范计算值进行对比.结果表明:实测值、有限元计算结果与《公路桥梁加固设计规范》计算值吻合良好;《混凝土结构加固设计规范》对于加固后大偏心受压构件新增纵向钢筋强度折减系数的选取较为准确,而对于小偏心受压构件的折减系数的选取偏于不安全,建议该折减系数的合理取值为0.8.

In order to solve the the problem of the difficulty of recognizing the internal force of a short suspender,the idea of an equivalent length is introduced with different boundary conditions of a short suspender. In view of the suspender,series of simulation data are used and the relationship between the equivalent length and dimensionless parameters ξ are obtained. The method of recognizing the internal force of a short suspender considers the influences of bending rigidity. The method here provides a meaningful exploration on recognizing the internal force of a short suspender.

For Guizhou anti-ice pavement, the paper using ANSYS built two kinds of finite element model of conductive carbon fiber anti-ice asphalt pavement. In the next section, heating performance and heating curve were calculated at 200 W/m2, 300 W/m2, 400 W/m2, 500 W/m2 and 600 W/m2 input power in the same external conditions, and compared the simulation results of carbon fiber-glass fiber grille anti-ice asphalt pavement to that of the physical model to verify the accuracy of the finite element model. Finally, the heating performance of two anti-ice pavements was analyzed and compared. The results show that the efficiency of carbon fiber-glass fiber grille anti-ice asphalt pavement has faster heating efficiency and higher energy use.

For the Guizhou province ice warning level, to make the anti-ice asphalt pavement response measures adapt for the ice warning level, the paper converted the warning level to ice thickness indicators before studying the ice-melting countermeasures. Then the paper further studied the relationship of ice-melting power-heating-up-time and ice-melting-ability of the pavement, and finally put forward specific response countermeasures to the ice warning.

由于地质条件的复杂性,影响边坡稳定性因素存在着不同程度上的不确定性.因此,在边坡稳定性分析中,应考虑这些因素的不确定,对边坡进行可靠度分析.文中将有限元强度折减法和点估计法结合进行边坡的可靠度分析.对有限元强度折减法和点估计法的基本原理进行了简单介绍,将二者相结合进行一黄土边坡的可靠度分析.计算结果表明,该边坡整体上较稳定,但可能发生黄土层的浅层滑动,边坡的平均安全系数为1.10,处于基本稳定状态.边坡的破坏概率为26.5％,属于低危险等级,需对该边坡进行进一步的观测.有限元强度折减法和点估计法相结合,可方便、简捷地对边坡可靠性进行评价.

为了较准确地预测碳纤维-玻纤格栅抗凝冰沥青路面化凝冰效果,利用ANSYS建立了碳纤维-玻纤格栅抗凝冰沥青路面有限元模型,根据对路面所处地区的标准气象资料及实地调研资料,确定了温度场的边界条件和初始条件,模拟计算了环境温度、风速、凝冰厚度等因素对碳纤维-玻纤格栅抗凝冰效率的影响规律.

Using conductive asphalt concrete (CAC) as a type of electro thermal element to melt snow and ice on highways is one of the most efficient, convenient, safe and environmental conservative methods. This paper focused on the influence of components on electrical and mechanical properties on CAC. Results show that the electrical performance of CAC depends on conductive filler content, types of conductive filler, and asphalt aggregate ratio. In order to realize the function of melting snow and ice, the best method to prepare CAC is to use both graphite powder (298# scale graphite) and short carbon fibers (CF) as mixer-filler. As the asphalt aggregate ratio is 8.0, the content of graphite is 50 wt.%, and CF content is between 2.5%∼4.0 wt.%, resistivity of CAC is close to or less than 102 Ω.cm. Marshall stability and flow value of CAC are also up to the national standard.

A kind of electrothermal concrete pavement is prepared using carbon black lightweight aggregate concrete as the surface layer, which has high electrical conductivity. The designed pavement model is tested in a simulated low-temperature environment. The relationship between the input electrical power and the temperature rising is observed. Studies have shown that at the same environmental temperature and the same period, the larger input power is applied, the higher temperature of the surface is obtained. As the thickness of the ice on the pavement is no more than 3mm and the ambient temperature are -10 ~-5°C, -15~-10°C, and -20~-15°C respectively, to meet the basic requirements of deicing, the electric power should be 400 W/m2, 500 W/m2, 600 W/m2 respectively. The electrical resistance of carbon black lightweight aggregate concrete keeps stable during the whole test. Thus, the electric power is stable.