钢筋混凝土结构服役性能在线评价与无损检测现状和展望

概述了国内外钢筋混凝土结构服役过程中的性能在线评价技术和无损检测技术 (包括动态无损评价技术和静态无损评价技术 )发展现状 ,重点阐述了建立钢筋混凝土结构服役可靠性和耐久性评价预测系统的必要性、重要性、理论基础和可操作性 ,展望了钢筋混凝土结构无损检测技术和无损检测仪器的发展趋势。     

后张法预应力混凝土桥梁施工技术应用研究

随着交通基础设施的快速发展,预应力混凝土桥梁因其优异的力学性能和施工效率广泛应用于各种桥梁工程中。其中,后张法预应力施工技术作为一种先进的施工方法,为预应力混凝土桥梁的施工提供了高效、安全和经济的解决方案。文章结合某跨河大桥项目,分析了后张法预应力混凝土桥梁的施工技术要点,旨在为类似桥梁工程的施工提供参考和借鉴。     

无粘结预应力混凝土在寒区公路桥梁中应用

介绍在我国寒区建成的第一座无粘结预应力混凝土桥梁的设计、施工、经济效益及静动载试验诸方面的主要情况,事实证明无粘结预应力混凝土技术完全可以用于寒区桥梁建设中     

安庆长江公路大桥斜拉索安装施工工艺

安庆长江公路大桥是双塔双索面悬浮式钢梁斜拉桥,斜拉索采用环氧喷涂钢绞线。本文重点介绍斜拉索安装施工工艺,介绍了辅助钢绞线在护套管安装中的应用以及单根张拉工艺。     

Reliability-based temporal and spatial maintenance strategy for integrity management of corroded underground pipelines

In this work, a novel stochastic model framework for predicting the external corrosion growth in buried pipeline structures has been developed, and a reliability-based temporal and spatial maintenance strategy is presented. The spatial correlation of soil properties is modelled via hidden Markov random field. The temporal correlation of the corrosion rate is characterised by the geometric Brownian bridge process. A Bayesian inferential framework is employed to estimate the model parameters of the corrosion growth model using in-line inspection data. The proposed corrosion growth model was validated with actual inspection data. In the reliability analysis, the impact of device detectability is considered and hence the estimated failure probability is more realistic. The proposed maintenance strategy is directly based on the time-specific and location-specific failure probability. The application of the proposed model and maintenance strategy is illustrated through a real-life pipeline system. The results indicate that the proposed maintenance strategy is an adaptive and dynamic scheme that is able to improve the efficiency of inspections.     

桥梁无损检测技术的形成与应用

指出无损检测作为一种可行的方法在桥梁检测中占有一席之地,较系统地阐述了桥梁无损检测技术的形成和发展,介绍了目前桥梁工程中常用的混凝土强度、缺陷、保护层厚度以及动力试桩等无损检测技术,为桥梁的维修、加固奠定了基础。     

Multi-tool inspection and numerical analysis of an old masonry arch bridge

Complex special inspection of an old masonry arch bridge according to the Guideline on Inspection and Condition Assessment of Railway Bridges and numerical analysis of the structure are presented. The guideline summarises recommendations for the step-by-step investigation of railway bridges applying enhanced methods developed during the EU-funded project Sustainable Bridges. For the investigation of the arch barrel, the ballast parameters and the inner structure of the backfill behind the arch barrel a number of various advanced non-destructive and minor-destructive testing methods were applied. Deformation of the structure during load tests was measured using three independent measuring systems: laser vibrometer, LVDT and microwave radar. Results of calculations performed with 2D and 3D models based on FEM are compared with the field load tests. Sensitivity of the ultimate load of the structure to investigated parameters is studied in FE model. Some general conclusions according to methods of testing and modelling of masonry arch bridges are presented and discussed.     

有粘结筋的锈蚀后张混凝土梁和钢丝破坏模式

对有粘结后张预应力混凝土梁的结构响应进行试验研究,建立数值分析模型。试验模拟了应力锈蚀的破坏效果,以及粘结筋在断裂端锚固的发展过程。测量了从加载到破坏的残余结构性能。考虑局部和整体参数,对带粘结预应力筋破坏以及加载梁的不同阶段,采用具有界面单元的非线性有限元模型进行模拟。假定预应力筋断裂引起的破坏分布出现在不同的位置,对不同的破坏模式进行了研究,总结了预应力结构的退化性能。     

Use of impulse radar as a method for the non-destructive testing of concrete slabs

The paper shows that Impulse Radar provides engineers and associated professions with an invaluable non-destructive testing tool and when used in conjunction with other methods of testing, Impulse Radar has an important role to play throughout the complete lifecycle of a structure.     

冲击回波法在混凝土路面质量检测中的应用

介绍了冲击回波法无损检测原理,阐述了冲击回波法无损检测技术在路面质量检测中的应用,将冲击回波法检测结果与钻芯取样测试结果进行对比分析,从而证实了该检测方法的可行性。     

Corrosion failure of post-tensioning tendons in alkaline and chloride-free segregated grout: a case study

This paper describes a case study of corrosion of post-tensioning strands in segregated grout that led to failure of one of the external tendons of a bridge after less than 2 years from the construction. Unexpectedly, severe corrosion attacks took place in areas where the ducts were filled by the injection grout, but segregation of the grout led to the presence of an unhardened whitish paste. A detailed inspection of the failed tendon, as well as other tendons removed afterwards, showed that corrosion occurred mainly in the inclined parts of the external post-tensioning tendons, in the presence of whitish grout. Analysis on samples of segregated grout showed that it was highly alkaline and had a high content of sulphate ions, but was free of chloride ions, excluding thus the normal causes of corrosion of steel in cement-based materials. Microstructural analysis of failed wires also excluded the failure for hydrogen embrittlement.     

混凝土透视仪在古建筑中的运用

喜利得PS1000混凝土透视仪可用于无损结构检测,探测钢筋混凝土结构和内部埋置物体,包括各类金属埋置物,如钢筋,预应力钢绞线,铜管,铝管,钢筋网,钢板,压型钢板等及各类非金属埋置物,如木材,空孔,塑料管道(水管),电缆等,并且定位深度可达30 cm,能高效评估和检查钢筋,钢筋网和检测物体内部的空心楼板,空腔。此次为检测古建筑北面墙体中是否有钢筋网及钢筋网方向、保护层厚度、锈蚀情况,采用喜利得PS1000混凝土透视仪进行无损检测,在达到检测目的同时又不损坏古建筑。     

混凝土超声波、声波检测的某些进展

超声波法是混凝土无损检测的主要方法之一.本文论述了混凝土超声波、声波检测技术的最新进展,介绍了超声波、声波层析成像技术在混凝土无损检测中的应用现状,与医学层析成像比较,分析了混凝土超声波、声波层析成像的困难所在,并对混凝土超声波、声波检测技术今后的发展提出了建议.     

自锚式后张法预应力筋伸长值计算与实测方法

以几座大桥工程预应力筋张拉施工为例,介绍自锚式后张法预应力筋张拉施工伸长值实测方法,推导预应力筋理论伸长值分段精确计算公式。     

Diagnostic load testing and assessment of existing bridges: examples of application

Load testing method is a significant tool in the assessment of bridge safety. One type of load tests is diagnostic load testing, the aim of which is to establish a comparison between real bridge behaviour and analytical calculation. It can be used either as acceptance test of the structures or as an estimation tool for the load carrying capacity of the already existing structures that have been in service for some time. This article presents diagnostic load tests and three examples of their application to various bridge structures and emphasises their diagnostic potential for assessment. In the majority of cases of diagnostic load tests presented in the literature, the experimental results (deflections, strains, etc) are very close or lower than the predicted ones and for this reason, such tests are expected to validate the existing structure. However, in the cases presented here, it is shown how the experimental results differ considerably from the expected ones. Since the theoretical and the experimental results of all three examples did not match, it was highly recommended to keep the matter under close investigation. A deep insight into the bridges showed serviceability and safety concerns and in some cases a repair/strengthening was necessary.     

地质雷达在PHC预应力管桩桩顶锚固钢筋检测中的应用

某工程结构施工封顶后,采用地质雷达对PHC预应力管桩桩顶内层锚固钢筋实施了检测。通过现场处理难点、现场调查分析,以及检测仪器的选用、现场检测、检测结果分析等,详细介绍了地质雷达无损检测技术的使用方法。并通过钻孔取样验证,表明地质雷达能够较准确地分辨出双层钢筋的位置。     

无损检测技术在实践中的应用

对某厂房所有的混凝土柱进行调查研究,发现局部排架柱的混凝土有较大深度的碳化,为了客观合理地评价厂房排架柱的结构有效承载能力,通过对这些排架柱的有限元计算模拟,从而计算出了受碳化混凝土影响的排架柱在静活荷载作用下的最大应力。