A structure database and its application: Maintenance Information Management System and Bridge Management System of Hanshin Expressway

For efficient management of various structures in a large highway network, systematic handling of data is essential since its volume has swollen over the years and it takes different forms such as diagrams and photos. The Maintenance Information Management System established by Hanshin Expressway Public Corporation (HEPC) is a computerized database and a processing and reference system of all bridge structure elements. As it is a comprehensive application, HEPC is also developing its own version of a bridge management system, which helps to plan annual budget allotments and work prioritization using the life cycle cost minimization rule. Both systems are tools to support a rational decision-making process of maintenance/repair programmes under the recent curtailed financial situation.     

Improving 410NiMo weld metal toughness by PWHT

Highlights of the present study is the importance of choosing suitable temperatures for two stage PWHT to achieve desirable toughness in the weld metals produced by ER 410NiMo filler wire. Weld pads prepared using this filler wire was used for extensive metallurgical characterization of the weld metal. Results indicate by choosing appropriate temperatures for the PWHT, it is possible to obtain toughness in the weld metal which is comparable to the toughness reported for the base metal of similar composition. Good toughness of the weld metal is attributed to the presence of retained austenite in the weld metal. Two stage PWHT that gave excellent toughness for the weld metal was employed for repair of cracked shrouds of a steam turbine in a nuclear power plant. The metallurgical characterization of the mock up weld pad prepared prior to actual repair confirmed that microstructure and hardness of the weld metal are similar to those obtained during the welding procedure development.     

Windows98注册表的维护及修复

通过Windows98注册表的分析，阐述了几种对Windows98注册表维护和修复的方法。     

Metabolic and DNA Repair Variations in Susceptibility to Genotoxins

An overview on the influence of metabolic and DNA repair polymorphisms on biological indicators of genotoxic risk in occupational, environmental, or lifestyle exposure is presented in this article. Indicators of genotoxic risk include biomarkers of internal dose (urinary concentration of the substance or its metabolites and urinary mutagenicity), biological effective dose (protein and DNA adducts), and indicators of early biological effects (chromosome aberrations, sister chromatid exchanges, micronuclei, COMET assay, HPRT mutants). Genetic polymorphisms include those involved in the activation and detoxification (i.e., P-450 cytochrome, acetyltransferase, glutathione transferase) of various classes of carcinogens and the newly discovered polymorphisms affecting DNA repair enzymes. Genetic polymorphisms are assessed for their importance in detecting the impact of genotype on biological indicators of genotoxic risk.     

Extending onshore pipeline repair to offshore steel risers with carbon–fiber reinforced composites

In the last 15 years, glass fiber hoop reinforced composite systems emerged as an acceptable, successful method for repairing corroded and mechanically-damaged onshore pipelines where the primary load is internal pressure. The feasibility of extending these repairs to offshore pipes such as risers require a thorough understanding of the complex combined load profiles; overlay of significant tension, bending, internal and external pressure. Herein an innovative design based on integrated computational models and full-scale tests is presented to address the viability of reinstating capacity to offshore pipelines and risers. The experimental program was based on a collaborative test matrix developed with the participation of composite repair manufacturers. The outcome guided and led to an easily deployable carbon–fiber composite repair system which was based on limit analysis methods and strain-based design techniques. It is anticipated that the results of this program will foster future investigations by integrating operator’s insight and in situ data gathering to extend composite repair for offshore needs.     

浅谈混凝土结构工程修复加固技术

在过去的50多年间,我国的土木工程建设发展极为迅猛.建筑物和构筑物建造、使用中出现的质量、维护问题,及其老龄化问题,引起人们的高度关注和重视,各种修补加固方法也不断出现,笔者根据自身的施工经验,对钢筋混凝土结构的加固施工中所遇到的加固施工方案及施工方法进行简单的介绍,并对不同方案进行优化比较.     

Overlay patch repair of scratch damage in carbon fiber/epoxy laminated composites

In this paper we present a numerical and experimental study on the overlay repair of scratch damage in carbon-fiber/epoxy composite laminates. The scratch damage severs several load bearing plies and results in a lack of symmetry in an originally symmetric multidirectional laminate. The ply-by-ply p-version finite element model is used to investigate the effects of the repair patch variables on the overall efficiency of the repair procedure and the lamina level stress states. The results show that interlaminar crack propagation in the direction parallel to the surface can be retarded with careful selection of repair parameters.     

Repair method and residual bearing strength evaluation of a locally corroded plate girder at support

There is growing interest in the maintenance and repair of bridges according to the increase in their service time. Many corrosion problems have especially been reported in plate girder bridges in support regions because of their high moisture level due to the bad air circulation, sediments, deposition, rain water, and antifreeze penetration in the drainage-type expansion joint. In this study, CFRP repair of a plate girder with localized corrosion at its support was proposed, and this method was used to repair the locally corroded plate girder around its support to examine the applicability and effectiveness of the corrosion repair method using CFRP. FE analysis of the corroded plate girder model was carried out to clarify the residual bearing strength and failure mode due to the localized plate girder corrosion in the web and stiffener at the support region. The application of the CFRP repair method to the plate girder bridge with local corrosion at its support showed that such method can be useful for corroded bridges due to its rapid and simple application and the stress level improvement on the repaired corroded surface on account of the sectional reinforcement effect of the CFRP repair and the prevention of the corrosion progress in the plate girder. The evaluation of the residual bearing strength of the plate girder with local corrosion at its support showed that such strength was affected more by the corrosion related to the stiffener than by the local web corrosion at the support. Therefore, to prevent local corrosion of a plate girder at its support, the corrosion ratio of the stiffener must be considered more than that of the web, and a corroded stiffener must be repaired or reinforced ahead of a corroded web.     

THE ANALYSIS OF MECHANICALLY FASTENED REPAIRS AND LAP JOINTS

Abstract— A new Dual Boundary Element formulation is presented, which allows for the analysis of mechanically fastened repairs and lap joints. The method requires only the boundaries of the problem to be discretized and the fasteners location is simply defined by a set of internal points.
The technique enables the evaluation of fastener forces, sheet stresses and the stress intensity factors which are important parameters for a Damage Tolerance assessment.
Examples of applications to repair designs and to a lap joint are presented to demonstrate the robustness of the new formulation that is proposed in this paper.     

我国工程机械维修的现状与发展

本文从维修思想，维修制度，检测技术，修复技术，建立维修市场，培养高素质的维修人才等方面阐述了我国工程机械维修的现状和发展趋向。