Prediction of Sewer Condition Grade Using Support Vector Machines

Assessing the condition of sewer networks is an important asset management approach. However, because of high inspection costs and limited budget, only a small proportion of sewer systems may be inspected. Tools are therefore required to help target inspection efforts and to extract maximum value from the condition data collected. Owing to the difficulty in modeling the complexities of sewer condition deterioration, there has been interest in the application of artificial intelligence-based techniques such as artificial neural networks to develop models that can infer an unknown structural condition based on data from sewers that have been inspected. To this end, this study investigates the use of support vector machine (SVM) models to predict the condition of sewers. The results of model testing showed that the SVM achieves good predictive performance. With access to a representative set of training data, the SVM modeling approach can therefore be used to allocate a condition grade to sewer assets with reasonable confidence and thus identify high risk sewer assets for subsequent inspection.     

Service Life Assessment of Existing Highway Bridges with No Planned Regular Inspections

Safety of a highway infrastructure system depends very much on the proper maintenance of bridges. The level of required maintenance is, typically, determined through a series of regular field inspections with the guidance of safety–economy trade-off. In Turkey, bridge maintenance, repair, and rehabilitation are currently performed on an as-needed basis. Time-dependent reliability analysis cannot be utilized for Turkish bridges for the time being since the majority of the bridges are either not regularly inspected or not inspected at all. The purpose of this paper is to propose a simple method to assess the remaining service life of a bridge by defining a relationship between its current condition rating and its age by evaluating a set of bridges at different ages. In a case study, 28 bridges were inspected for the first time to assess the average life expectancy. The average life of a bridge was predicted to be 80?years, and for this set of bridges, the main body components were found to deteriorate more than earth retaining and serviceability components.     

残极加料机液压系统改进

残极加料机是贵冶熔炼车间重要的生产设备,通过该设备可以很安全的把粗铜或残极加入到转炉炉内。其主要功能都是液压系统来完成。重点介绍液压系统相关的设计原理,推入油缸故障的处理方法等。本次系统改进参考了一期日本大金设计的液压系统,在日方设计的基础上删除了繁琐的环节,使整个系统简单明确,更符合现场的工作状况。     

Inspection and Risk Assessment of Concrete Culverts under Ohio’s Highways

In 2003 the Ohio Department of Transportation (ODOT) implemented a new culvert management program. Simultaneously, a team of researchers from the Ohio Research Institute for Transportation and the Environment (ORITE) and engineers from a private consulting firm conducted a joint study to evaluate the effectiveness of field culvert inspection and rating procedures proposed by the ODOT’s new program and describe the best remedial measures currently available for highway culverts. This paper focuses on the first component and addresses it relative to concrete culverts. The new inspection procedure for concrete culverts was applied at 25 sites. Inspection data were examined to detect common problems existing at concrete culvert sites in Ohio. The field data were also analyzed using statistical software to identify factors that contribute to the degradation of concrete culverts. Despite the limited amount of data, the results indicated that the ODOT approach was basically sound. The final segment of the paper presents a risk assessment method developed by the ORITE researchers. The proposed risk assessment method computes the overall structural health rating for any inspected culvert and recommends a course of action.     

铝板带冷轧机液压系统的污染控制与管理

通过介绍铝板带冷轧机液压系统的污染控制,从元件管理、系统维护、系统安装、油品管理检测等几方面入手,控制系统污染,提高系统工作可靠性,延长系统元件使用寿命。     

Performance of a Tied-Arch Reinforced Concrete Railway Bridge: Rating, Safety Assessment, and Bond Length Evaluation

This study presents investigations regarding visual inspection, dynamic testing, and finite-element modeling of an approximately 80-year old reinforced concrete tied-arch railway bridge that is still in service in Turkey. Investigations were conducted as part of a systematic periodic inspection along Ankara-Zonguldak railway line. The bridge is subject to heavy freight trains with increasing axle loads. Field tests such as material tests and dynamic tests were used to calibrate the finite-element model of the bridge. Detailed information regarding testing and model updating procedure is given. Based on test results, computer model was refined. The calibrated model of the bridge structure was then used for structural assessment and evaluation. Despite sufficient overall safety, local details were found to be problematic. Due to insufficient bond length in hanger-to-arch connection, a strengthening scheme using steel channel sections was proposed.     

液压系统设备的整合改进

通过对大型液压系统的开发,合理地对部分设备改造,可大大减少企业生产中的维护成本,大大减少设备工人的维护量。     

1250轧机卷取机液压钳口故障诊断及技术改造

通过对1250轧机机组的卷取机液压钳口故障诊断和原因分析,并对钳口油缸的活塞进行了技术改造,最终实现了轧机卷取机液压系统更换维修与1250轧机机组的正常维护检修时间同步,从而大幅度地提高了轧机作业时间,取得了较好的经济效益．     

Reliability as Tool for Hydraulic Network Planning

This paper presents a methodology to evaluate the reliability of water distribution systems that can be used in the design phase and for identifying repair works to be carried out on existing systems. The methodology is based on the statistical analysis of dimensionless performance indices (hydraulic performance indices) derived from a large number of simulations of various water system demand scenarios and∕or operating conditions. The hydraulic reliability index is assumed as the probability that, under a given operating condition, the hydraulic performance index will be above a certain threshold. Finally, the system's overall reliability (mechanical + hydraulic) is estimated using the overall reliability index, which is defined by the weighted mean of the hydraulic performance indices obtained for the various operating conditions. A case study using this methodology shows the concrete possibilities of applying this approach to a wide spectrum of cases, and the small influence on overall system reliability normally exerted by such events as the failure of links, pipes, and valves.     

Sepiolite as an Alternative Liner Material in Municipal Solid Waste Landfills

Compacted clay has traditionally been used as a lining material in municipal solid waste landfills. However, natural clays may not always provide good contaminant sorption properties. One alternative material that is abundant in some parts of Europe and Turkey as well as Western United States is sepiolite. A laboratory study was undertaken to investigate the feasibility of sepiolite as a liner material. Two clays, one rich in sepiolite and the other one rich in kaolinite mineral, as well as their mixtures were subjected to geomechanical, hydraulic, and environmental tests. The same soils were also subjected to strength and hydraulic conductivity tests after a series of freeze and thaw cycles. The results of the study indicated that relatively high hydraulic conductivity and shrinkage capacity of sepiolite necessitates addition of kaolinite before being used as a landfill material. The valence of the salt solutions affected the swell and hydraulic conductivity characteristics of the clays tested. Retardation factors for sepiolite for metal solutions are 1.2–2.2 times higher than those calculated for the clay that is rich in kaolinite, and the inorganic contaminant adsorption capacity of the clay can be improved by addition of sepiolite. The results indicated that the clay mixtures utilized in this study provide good geomechanical, hydraulic, and metal adsorption properties which may justify their potential use as a liner material in solid waste landfills.     

Evaluation of the Design, Planning, Construction Phases, and Structural Content of Permanent Residential Dwellings Built after the 1999 Eastern Marmara Earthquakes in Turkey

The aim of this study is to survey and evaluate permanent housing structures built after the Marmara earthquakes based on the principles of earthquake resistant design of reinforced concrete structures. The seismicity of Turkey requires immediate attention as there is a high probability of another major earthquake event in the next 30?years in Istanbul. The classification of structural systems, the damage patterns and behaviors of structural systems, and structural and nonstructural components under lateral earthquake loads, are analyzed. Based on this analysis, reliable structures can be built without overextending the Turkish economy, and loss of life and structural damage can be reduced by designing structures with greater earthquake energy dissipation capacity. The selection of project areas and the strength of the structural system are thoroughly analyzed taking postearthquake public psychology into account. Structural characteristics of permanent housing built subsequent to the Marmara earthquakes are critiqued and documented with a case study.     

Case Study: Refinement of Hydraulic Operation of a Complex CSO Storage/Treatment Facility by Numerical and Physical Modeling

The performance of a combined sewer overflow (CSO) storage/treatment facility in North Toronto, Ont., Canada, was investigated by conjunctive numerical and physical (hydraulic) modeling. The main objectives of the study were to (1) assess the feasibility of increasing the hydraulic loading of the CSO facility without bypassing; and (2) establish a verified numerical model of the facility for future work. The numerical model [a commercial computational fluid dynamics (CFD), PHOENICS] was validated and verified using results from a hydraulic scale model (1:11.6). The results obtained show that the CFD model can simulate hydraulic conditions in the facility well, as demonstrated by accurate reproduction of the filling rate, water levels at various locations, flow velocities in feed pipes, and overflows from the inflow channel. Numerical simulations identified excessive local head losses and helped select structural changes to reduce such losses. The analysis of the facility showed that with respect to hydraulic operation, the facility is a complex, highly nonlinear hydraulic system. Within the existing constraints, a few structural changes examined by numerical simulation could increase the maximum treatment flow rate in the CSO storage/treatment facility by up to 31%.     

Simulating Water Management and Supply Effects at the Office du Niger Collective Canal Irrigation Scheme

This paper demonstrated how a modeling approach can be used to find the optimal mix of farmers’ water management practices to improve irrigation efficiency at the tertiary level in collective canal schemes. The approach is developed for the case of the Office du Niger and based on a field study of 3?years. First, a simulation model is presented in which all relevant physical and social aspects of water management at the farmers’ level are considered. Next, simulations are performed to evaluate the impact on performance of different combinations of management practices and different external conditions. Finally, the combinations are selected that succeed in limiting seasonal water consumption to 1,400?mm and avoiding irrigation problems, but which are also realistic from a farmer’s point of view. Results demonstrate that in the Office du Niger, where seasonal water consumption per hectare should be reduced by about 30%, a tight control of the tertiary intake in combination with a good maintenance of the tertiary canal should be proposed. Although the model software is built especially for the case of the Office du Niger, the concept of the model can be transferred to other irrigation schemes, as it uses only simple hydraulic principles and limited data input.     

精整线液压系统液位低位保护的改造

通过对带钢精整线十二个液压系统的现场调查、统计、计算 ,指出了低液位运行产生的危害和造成的后果 ,阐述了改造的具体措施 ,改造后的效果     

Deterioration Rates of Typical Bridge Elements in New York

The New York State Department of Transportation (NYSDOT) maintains an inventory of over 17,000 highway bridges across the state. These bridges are inspected biennially or more often as necessary. Bridge inspectors are required to assign a condition rating for up to 47 structural elements of each bridge, including 25 components of each span of a bridge, in addition to the general components common to all bridges. The bridge condition rating scale ranges from 7 to 1; 7 being new and 1 being in failed condition. These condition ratings may be used to calculate the deterioration rates for each bridge element, while considering the effects of key factors, such as the bridge material type, on the deterioration rates. This paper describes an approach based on the Weibull distribution to calculate the deterioration rates of typical bridge elements in New York State using historical bridge inspection data and compares the results with those using the traditionally used Markov chains approach. It is observed that the Weibull-based approach performs better in terms of the observed conditions than the traditionally used Markov chains approach for developing deterioration curves for different bridge elements. Both Markov chains and Weibull-based approaches have been incorporated into a computer program that generates the deterioration curves for specific bridge elements based on historical NYSDOT bridge inspection data dating back to 1981. Case studies on the deterioration rates of various bridge elements in New York State are presented to demonstrate the two approaches. The case studies show that the element deterioration rate information can be used to determine the expected service life of different bridge elements under a variety of external factors. This information is extremely valuable for making bridge management decisions. Based on the Weibull-based approach, the deterioration rates for typical bridge elements in New York State have been presented.     

Hydraulic Deterioration Models for Storm-Water Drainage Pipes: Ordered Probit versus Probabilistic Neural Network

A decrease in discharge capacity of storm-water drainage pipes is the result of the so-called hydraulic deterioration which reduces the cross sectional area of pipes and increases the pipe roughness. Hydraulic deterioration is caused by tree root intrusion, sediment accumulation, and encrustation, and is affected by many influential factors such as pipe size and pipe location. Predicting hydraulic deterioration is important for effective management of drainage pipes. An ordered probit deterioration model (OPDM) and a probabilistic neural network deterioration model (PNNDM) were developed in this study using the influential factors as model inputs and the hydraulic condition as model output. Their predictive performances were compared against each other using a case study from Melbourne, Australia with a sample of 417 storm-water drainage pipes subjected to closed circuit television inspection. The results show that the PNNDM is more suitable for predicting the hydraulic deterioration and outperforms the OPDM. Several input factors such as pipe size and pipe age are found significant to the hydraulic deterioration.     

基于最小应变能密度因子断裂准则的岩石裂纹水力压裂研究

建立了考虑裂纹尖端非奇异项T应力的最小应变能密度因子断裂准则, 研究了不同裂纹类型条件下T应力和泊松比对起裂角的影响, 结果表明裂纹起裂角不仅与奇异项应力强度因子有关, 而且还需要考虑非奇异项T应力和泊松比的影响作用.同时计算了含井筒对称双裂纹水力压裂模型的起裂角和临界水压, 表明依据本文断裂准则计算得到理论解与实验结果吻合良好.在此基础上, 利用该准则从理论上分析了临界裂纹区尺寸、T应力、比奥系数、侧压系数、泊松比等因素对水力压裂裂纹起裂特性的影响.参数分析表明: 临界裂纹区尺寸、T应力和侧压系数对临界水压和临界起裂角有显著影响.临界水压随着泊松比增大而减小, 而临界起裂角呈现相反变化趋势.比奥系数对临界起裂角没有影响, 但是在高水压条件下对起裂角具有显著影响.      

Assessment of Cable Maintenance Technologies for Honshu-Shikoku Bridges

A dry-air injection system developed as a new anticorrosion method for the suspension bridge cables used in Honshu-Shikoku Bridges has been implemented. In this paper, applicability of this system to existing suspension bridges employing traditional anticorrosion measures, as well as to newly constructed ones, is reported. Along with this development, several suspenders in a suspension bridge, which had been in service for 17 years, were opened up for inspection. A characteristic pattern of corrosion was observed in this investigation. Also, nondestructive inspections of bridge suspenders based on principles of magnetism were carried out on-site and indoors. Effectiveness of this nondestructive inspection method is discussed in this paper, referring to comparisons between the results of the exposed inspection of suspenders and those of nondestructive inspection.     

数字化技术在曲柄起停式飞剪上的应用

为了解决曲柄起停式飞剪原有模拟控制系统存在的问题,在技术改造中采用了由西门子公司可编程控制器S7-300和直流传动装置以6RA70以及工业现场总线PR0FIBUS-DP联网组成的全数字电控系统.采用了全数字电控系统后,设备作业率提高,工艺性能改善,维护量显著降低,充分显示出模拟系统的数字化是设备改造与技术创新的方向.     

TH430自卸卡车液压系统高温分析与解决

本文对TH430井下专用自卸卡车在实际使用过程中液压系统存在的高温问题进行了阐述与分析,通过对液压油冷却散热器进行合理化防护改造,解决了存在的问题,并创造了显著的经济效益。