《混凝土结构》课程教学方法思考与探索

作为土木工程专业的重要专业课程。为提高学生分析思考能力和创新意识,在讲授该课程时教师的教学理念和教学方法也要不断地变化,与新理论和新方法的发展相适应。本文针对《混凝土结构》课程所具有的特点,结合几年教学体会,从培养兴趣、多媒体教学、强化实践教学,课堂讨论,信息化模式教学等方面来提高教学效果进行了一些实践与探索。中央高校基本科研业务费专项资金资助项目(20720160076

STRUCTURAL MONITORING TECHNIQUES FOR XIAMEN XIANG'AN SUBSEA TUNNEL

海底隧道由于其特殊及地质环境的复杂性,为保证海底隧道钢筋混凝土的耐久性与结构服役能力,对其腐蚀状态进行监测尤为迫切。该文研究了翔安隧道钢筋腐蚀监测系统的设计,包括商用的以及基于电化学和物理方法的自主研发的腐蚀传感器,腐蚀监测断面与测点的布置、腐蚀传感器的安装,以及腐蚀数据库的建立。通过现场采集的腐蚀监测数据,评价了翔安海底隧道目前的腐蚀状况。最后介绍了基于超声导波的钢筋腐蚀监测研究新进展。Due to the particular and complex engineering environment of subsea tunnels, it is especially imperative to monitor the condition of steel corrosion in reinforced concrete(RC) of subsea tunnels for structural serviceability and durability of RC structures. In this paper, the largest excavation section subsea tunnel-Xiamen Xiang'an subsea tunnel is studied. Especially, the design of corrosion monitoring system is focused due to its complexity. Both the commercial corrosion sensors and the developed corrosion sensors based on electrochemical and fiber Bragg grating(FBG) techniques are adopted. The arrangement of the corrosion monitoring sections, their location, the installation of the sensors and the establishment of corrosion database are discussed. Then, the evaluation of corrosion in subsea tunnel is established based on the monitoring data of reinforced concrete collected in field. Based on the monitoring data collected in the field of the subsea tunnel, the status of stress and corrosion in Xiamen Xiang'an subsea tunnel can be evaluated. Finally, the promising technique based on ultrasonic guided waves for monitoring steel corrosion in RC is also discussed.国家自然科学基金项目(51378445);; 福建省闽江学者科研资助项目;; 中央高校基本科研业务费专项资金资助项目(20720160076

平板法试验研究高强与高性能混凝土抗裂性能

高强与高性能混凝土胶结料用量较多,砂率较大,粗骨料用量相对较少,而且水胶比较低,常掺有其它掺合料,因此若处理不妥易出现混凝土早期开裂现象.本文在圆环法试验的基础上通过平板法试验,研究分析不同水胶比和不同粉煤灰掺量对高强与高性能混凝土开裂性的影响.研究结果表明,高强与高性能混凝土的裂缝主要发生在早期,因此在早期就应该及时采取控制裂缝的措施;在低水胶比的情况下,水胶比对高强与高性能混凝土抗裂性能的影响较为明显,水胶比越小,开裂越严重;掺入粉煤灰对混凝土抗裂有所改善,但是其掺量对抗裂的影响并不是呈定向规律,而是存在着最优掺量

BRT路面快速修复和养护技术研究

快速公交BRT自2005年引入我国,现已在多个城市建成运营,但基于BRT完全渠化的运营方式及公交车大、重、长的特点,在已建成BRT的车站和进、出站路段的路面发现不同程度的车辙、推移等病害。比较了国内外当前对于BRT路面养护修复技术的发展进程,包括传统方法与目前出现的新技术,并以厦门BRT为例,提出合适的病害修复措施,探讨今后研究的发展方向。福建省中青年教师教育科研项目(JAT160004

Seismic Response Sensitivity Analysis of Soil-Structure Interaction Systems

本文概述了基于直接微分法的非线性有限元动力响应对于模型材料参数、几何参数和地震不确定性参数的敏感性分析方法,介绍了基于力法、位移法和三场混合法等方法的有限单元直接微分法敏感性分析最新进展,并着重讲述了将直接微分法拓展到非线性结构和岩土等材料模型中,用于分析土-结相互作用体系的敏感性分析方法。本文将此敏感性方法应用到一个有实际工程背景的受双向地震荷载作用下的三维土-结相互作用体系中,通过有限差分法证明敏感性分析计算结果的高效性和正确性,验证了此方法应用到实际工程中的有效性和实用性。直接微分法由于计算得到的是半解析解,具有精确、高效、不受数值噪音干扰等优点,具有潜在重要的工程价值。Sensitivities of the FE response with respect to both model( material or geometry) and loading parameters represent an essential ingredient in studying the structures.This paper presents recent developments in FE response sensitivity analysis based on the Direct Differentiation Method( DDM) for displacement-based,force-based,and three-field mixed finite elements,with a focus on the extensions of the DDM to nonlinear material constitutive models of structural or geotechnical systems.DDM based response sensitivity analysis methods are used to analyze a real three dimensional nonlinear soil-structure interaction system under bi-directional seismic load to verify its accuracy,efficiency and applicability to engineering problems.The DDM has semi-analytieal solution and is accurate,effective and not disturbed by numerical noise,it has latent engineering value.国家自然科学基金(51261120376;51281220267); 冻土工程国家重点实验室资助(SKLFSE201405

未知激励下的无迹卡尔曼滤波新方法

无迹卡尔曼滤波(UKF)是一种识别非线性系统的有效方法,然而传统的UKF方法需要观测外部激励,这限制了UKF的应用范围。迄今为止,国内外对未知激励情况下的UKF方法的研究还非常少。该文在传统UKF的基础上,推导出在未知激励情况下的无迹卡尔曼滤波(UKF-UI)方法的递推公式,通过对观测误差的最小化,利用非线性方程求解,识别未知外部激励,进而识别非线性结构系统状态与结构未知参数。进一步采用融合部分观测的加速度响应及位移响应,消除识别结果的漂移问题。分别通过白噪声和未知地震作用下识别非线性迟滞模型的两个数值算例,考虑观测噪声对非线性系统进行识别,从而验证提出新方法的有效性。结果表明,该文所提出的UKF-UI方法,能够在部分观测结构系统响应的情况下,有效地识别非线性结构参数和未知激励。国家自然科学基金资助项目(51678509);;\n福建省自然科学基金项目(2016J01263);;\n中央高校基本科研业务费专项资金资助项目(20720160076);;\n住房和城乡建设部科技项目(2016-K4-046);;\n厦门市交通基础设施智能管养工程技术研究中心资助项目(TCIMI201815

Advances of monitoring corrosion in reinforced concrete based on UGW

Conference Name:2013 2nd International Conference on Sustainable Energy and Environmental Engineering, ICSEEE 2013. Conference Address: Shenzhen, China. Time:December 28, 2013 - December 29, 2013.Monitoring the condition of steel corrosion in reinforced concrete (RC) is imperative for ensuring structural serviceability and durability of RC structures. The techniques based on ultrasonic guided wave (UGW) gain more and more popularities as they have many advantages for monitoring corrosion in reinforced concrete. In this paper, UGW based monitoring techniques in the past decade are reviewed, including corrosion monitoring mechanism and feature extraction, monitoring corrosion induced deboning, monitoring pitting corrosion, monitoring corrosion induced interface roughness. Finally, the challenges and future trends in the development of UGW based monitoring techniques for condition assessment of corrosion inreinforced concrete are put forward in this paper. ? (2014) Trans Tech Publications, Switzerland

BRT路面铺装方案研究

BRT特有的渠化交通方式和较重的车辆荷载容易使BRT路面在运营较短时间内就出现车辙等病害。文章在对比现有施工方案不足的基础上,借鉴北京BRT铺装案例,并对其各项性能进行试验分析,针对厦门BRT高架段路面提出TX铺装新方案的设想。福建省中青年教师教育科研项目(JAT160004);;中央高校基本科研业务费专项资金资助项目(20720160076);;住房和城乡建设部科技项目(2016-K4-046

Physical based techniques for monitoring corrosion in RC

Conference Name:3rd International Conference on Civil Engineering and Transportation, ICCET 2013. Conference Address: Kunming, China. Time:December 14, 2013 - December 15, 2013.It is imperative to develop effective techniques to monitor the condition of steel corrosion in reinforced concrete (RC) for ensuring structural serviceability and durability. In the past decade, some physical based techniques have been proposed as alternative tools for monitoring corrosion. These physical based monitoring techniques can conduct accurate condition assessment of steel corrosion through direct measurements on embedded steels. In this paper, some primary physical based monitoring techniques for condition assessment of steel corrosion in reinforced concrete in the recent years are presented and the challenges and future trends in the development of physical based monitoring techniques for condition assessment of corrosion in reinforced concrete are also put forward. ? (2014) Trans Tech Publications, Switzerland

Review of Physical Based Monitoring Techniques for Condition Assessment of Corrosion in Reinforced Concrete

National Natural Science Foundation of China (NSFC) [51178406]; State Key Laboratory for Disaster Reduction in Civil Engineering at Tongji University, China [SLDRCE10-MB-01]; Key Project of Fujian province of China [2013Y0079]Monitoring the condition of steel corrosion in reinforced concrete (RC) is imperative for structural durability. In the past decades, many electrochemistry based techniques have been developed for monitoring steel corrosion. However, these electrochemistry techniques can only assess steel corrosion through monitoring the surrounding concrete medium. As alternative tools, some physical based techniques have been proposed for accurate condition assessment of steel corrosion through direct measurements on embedded steels. In this paper, some physical based monitoring techniques developed in the last decade for condition assessment of steel corrosion in RC are reviewed. In particular, techniques based on ultrasonic guided wave (UGW) and Fiber Bragg grating (FBG) are emphasized. UGW based technique is first reviewed, including important characters of UGW, corrosion monitoring mechanism and feature extraction, monitoring corrosion induced deboning, pitting, interface roughness, and influence factors. Subsequently, FBG for monitoring corrosion in RC is reviewed. The studies and application of the FBG based corrosion sensor developed by the authors are presented. Other physical techniques for monitoring corrosion in RC are also introduced. Finally, the challenges and future trends in the development of physical based monitoring techniques for condition assessment of steel corrosion in RC are put forward