Dynamic Anomalies in a Modular Bridge Expansion Joint

Environmental noise complaints from homeowners near bridges with modular bridge expansion joints (MBEJs) led to an engineering investigation into the noise production mechanism. The investigation identified modal vibration frequencies in the MBEJ coupling with acoustic resonances in the chamber cast into the bridge abutment below the MBEJ. This initial acoustic investigation was soon overtaken by observations of fatigue induced cracking in structural beams transverse to the direction of traffic. These beams are, in the English-speaking world, universally referred to as center beams. However, in Europe the term lamellae is equally common. A literature search revealed little to describe the structural dynamics behavior of MBEJs but showed that there was an accepted belief dating from around 1973 that the loading was dynamic. In spite of this knowledge many bridge design codes used throughout the world specify a static or quasi-static load case with no mention of the dynamic behavior. This paper identifies the natural modes and operational response modes of vibration of the MBEJ installed into Sydney’s Anzac Bridge. In addition, the paper will introduce the dynamic range factor (DRF) and report a DRF of 4.6 obtained after extensive static and dynamic strain gage measurements. The studies indicated that the Anzac Bridge MBEJ was very lightly damped (<2% of critical) and a reduction in the measured DRF through the introduction of additional damping was an option.     

Design and Installation of Fiber-Reinforced Polymer Composite Bridge

This report describes the installation and testing of a fiber-reinforced polymer composite highway bridge located in Butler County, Ohio. The bridge was designed to meet AASHTO HS-20 load requirements based on strength and maximum deflection. The installation demonstrated fiber-reinforced polymer composite highway bridges could be installed in significantly less time than a traditional reinforced concrete bridge. When fully loaded the bridge deflected less than the maximum AASHTO HS-20 deflection values.     

Investigation of Bridge Expansion Joint Failure Using Field Strain Measurement

This study was initiated after the sliding plate expansion joints of Millard E. Tydings Memorial Bridge, a long-span truss bridge, failed prematurely just a few months after their initial installation. The study included field investigation, material testing, analysis, and field testing. Test data records show numerous high spikes, which represent high tensile stresses, within their respective measured periods. By extrapolation, the failure was predicted by applying Miner’s linear cumulative damage rule. The calculation shows that the accumulative value would reach 1.0 when the first and subsequent failures were reported. The unexpected high stresses and poor workmanship caused early crack formation attributable to distress.     

高压并联电容器的安装、运行和维护

电力系统的无功补偿方式之一是通过并联电容器来完成的,并联电容器是提高系统功率因素,降低电能损耗,提高电压质量和设备利用率的有效途径。并联电容器作为电力系统重要设备,是企业用电实现"节能"方法之一,并联电容器从安装运行、维护的好坏可直接影响到企业对电能的利用。本文介绍了并联电容器的安装、运行和维护方法。     

Life-Cycle Cost Based Maintenance Plan for Steel Bridge Protection Systems

Life-cycle cost analysis was used to compare different alternative strategies for steel bridge paint systems. It was also used as a tool for steel bridge paint rehabilitation planning. The existing paint systems are lead-based and zinc-vinyl, while the new system is an inorganic/organic zinc, epoxy, and urethane paint system (three-coat). Economic analysis using present value (PV) and equivalent uniform annual cost (EUAC) was applied to compare several steel bridge paint system alternatives. The PV and EUAC were also used to compare different rehabilitation scenarios within the same alternative. Life-cycle cost analysis computations indicate that the three-coat paint system was better than others. Researchers concluded that the best scenario for three-cost system rehabilitation was doing spot repairs every 15 years of paint life. A maintenance plan based on life-cycle cost analysis also favored the “spot repairs every 15 years” scenario. A sensitivity analysis was also conducted to account for uncertainty in the cost, conditions, and subjective data.     

连铸机钢包迴转台的安装与维护

介绍了连铸机钢包迴转台的工作原理、结构，以及安装与维护方面的要点。     

冶金机械设备的安装施工和维护浅析

随着冶炼技术的不断提升,冶金行业对相关生产设备的要求逐步提高。冶金行业具有设备大型化、环境特殊化、产能效率化等特点,为使施工能正常运作,加强安装的科学性,以达到减少设备消耗成本、提高生产效率和延长工作周期的目的,冶金工程机械设备的安装施工和维修需要在信息化和技术化相结合的条件下实施。本文重点分析冶金机械设备安装施工的要点,详细阐述了冶金设备的维护方法与标准设置,以于提高机械设备的生产率与利用率。     

沙钢辊底式热处理炉炉辊设计安装及使用维护技术探讨

介绍沙钢辊底式钢板热处理炉炉辊设计、制造、安装等方面先进技术的应用,炉辊安装、调整、检测、使用及维护中出现的典型问题的处理。     

直流传动SCR装置的维护与故障诊断

本文介绍了直流传动ＳＣＲ装置的维护与故障现象及其产生原因，并提出了检查内容。     

炼铁设备的维护与管理

通过维护管理好炼铁设备,可减少停工损失和维修费用,降低成本,提高生产效率。另外,要正确安装设备的零部件,在使用过程做好日常维护,减少磨损和腐蚀,加强日常检查,及时发现问题和解决问题,保证设备安全。     

Evaluation of Performance of Bridge Deck Expansion Joints

The bridge deck expansion joint is an important element in the functioning of bridge structures. When joints fail to function properly, they can create problems out of proportion to their size. Selection of a good joint for use can create fewer bridge maintenance problems. The purpose of the study was to evaluate the performance of several types of joints currently in use on Indiana highway bridges. The types of joints investigated are compression seal, strip seal, integral abutment, poured silicone, and polymer modified asphalt. The research was accomplished through questionnaire surveys, analysis of Indiana Department of Transportation roadway management data, and expert interviews. The questionnaire survey identified the problems and their causes and the merits and potential improvements of each type of joint. The analysis of Indiana roadway management data ranked the performance of different types of joints based on the deterioration rates estimated by the regression coefficients. The expert interviews investigated the practices of Indiana and its surrounding states regarding the selection and maintenance of joints. Based on the research results, several suggestions were proposed to ensure the longer service life of expansion joints.     

送料装置的设计与实践

详细介绍了送料装置各参数的选择方法和使用情况。此装置是为了提高首架轧机对钢坯的咬入能力而设计的一架送料装置。     

省煤器的检修及其管道安装中的几个问题

1前言近年来,随着中小企业的迅猛发展,全国各地中小型快装锅炉的数量和单位容量增加很快。通过对本地区及其他部分地方4 t/h以下工业快装锅炉的调查发现,对于铸铁式非沸腾省煤器的检修及其管道安装方面存在一些问题,在此结合本单位的实际使用情况,介绍其相应的对策措施。2对于有备用锅炉的企业,一般未装设省煤器旁通烟道,但省煤器的顶部鳍片积灰就没有办法清除这种情况是很普遍的,由于该种铸铁式省煤器为鳍片型(加强传热),其鳍片之间以及鳍片与外壳箱板之间的间隙较小(约30 mm),燃煤快装锅炉在运行一段时间后,其烟管内将产生大量的烟垢,烟垢…     

波纹管膨胀节在热力管道中的应用

城市集中供热管线中,采用波纹管补偿器实现热补偿,是一种经济可行的方法,但具体应用时要充分考虑工程的实际情况,选择合适的补偿器才能达到预期的效果。     

桥式起重机机械系统故障及维修

天车广泛应用于冶金行业，分析其常见故障及原因，通过维修排除故障，从而保证天车设备的完好。保证天车的安全运行。     

螺旋密封装置的设计

本文对螺旋密封工作原理进行了理论分析，且结合实际情况对螺旋密封装置进行了设计，较好地解决了轧机主传动装置“动点”密封。     

Assessment of Bridge Expansion Joints Using Long-Term Displacement and Temperature Measurement

A procedure for assessment of bridge expansion joints making use of long-term monitoring data is presented in this paper. Based on the measurement data of expansion joint displacement and bridge temperature, the normal correlation pattern between the effective temperature and thermal movement is first established. Alarms will be raised if a future pattern deviates from this normal pattern. With the established correlation pattern, the expansion joint displacements under the design maximum and minimum temperatures are predicted and compared with the design allowable values for validation. The extreme temperatures for a certain return period are also derived using the measurement data for design verification. Then the annual or daily-average cumulative movements experienced by expansion joints are estimated from the monitoring data for comparison with the expected values in design. Because the service life and interval for replacement of expansion joints rely to a great extent on the cumulative displacements, an accurate prediction of the cumulative displacements will provide a robust basis for determining a reasonable interval for inspection or replacement of expansion joints. The proposed procedure is applied to the assessment of expansion joints in the cable-stayed Ting Kau Bridge with the use of one-year monitoring data.     

设备检修安装工程签证在项目造价控制中的作用

介绍了设备检修安装项目造价管理中现场工程量签证暴露的问题,进行了理论分析,并对其中的关键环节提出了改进措施,在有效缩减一定比例项目造价的同时,真实客观地反映设备检修安装工程造价。     

钢包内衬膨胀缝对热应力的影响研究

利用有限元法建立了钢包内衬膨胀缝的有限元模型,探讨了膨胀缝对钢包热应力的影响,研究了采用不同膨胀缝的钢包热应力变化,找出了膨胀缝对热应力的影响规律,并得到了较佳的膨胀缝值。     

钢包内衬膨胀缝对热应力的影响研究

利用有限元法建立了钢包内衬膨胀缝的有限元模型,探讨了膨胀缝对钢包热应力的影响,研究了采用不同膨胀缝的钢包热应力变化,找出了膨胀缝对热应力的影响规律,并得到了较佳的膨胀缝值。