桥门式起重机安全技术检验现状分析

本文通过对桥门式起重机安全技术检测，从安全装置，电气，机械，金属结构零部件等方面分析桥门式起重机安全技术情况，说明实行起重机械安全监察和检测检验对企业加强起重机械安全管理，杜绝和减少起重伤害事故具有重要意义。     

大型重载桥吊箱形主梁在轨面恢复上挠度的探讨

本文对大型重载桥吊恢复上挠度的方法和工艺进行探讨，并提出了大型重载桥吊箱形主梁在轨面恢复上挠度的解决方案。     

逆变桥不对称保护电路的研究

介绍了一种新的逆变电源逆变桥的不对称保护电路。该电路利用了电路拓扑的分析方法，对逆变桥的工作状态实行瞬时式采样监控。它能准确无误地检测出逆变桥的运行状态是否正常，并使处于“三桥臂”运行的逆变电源得到迅速而有效的保护。克服了现行逆变电源采用的“斜通保护”方法所存在的采样的间接性和保护的不完全性。     

6m焦炉桥管的更换

对6m焦炉桥管断裂或通洞造成荒煤气、氨水、焦油外漏污染环境的问题，用装煤车及其上安装的卷扬机作为运输和吊装工具．采取固定上升管更换桥管的办法．可在不影响生产的情况下，得到有效解决。     

向家坝大桥设计与施工

介绍了长江三峡库区湖北省秭归县向家坝大桥的基本情况，并对该桥钢管混凝土空间桁架组合梁式结构连续刚构的设计构思、施工情况作了详细的阐述，还将该桥材料用量及技术经济指标与一座类似跨径的预应力钢筋混凝土连续刚构的箱梁作了比较。     

宜昌长江公路大桥钢箱梁工地焊接施工精度控制

大跨度钢桥中，由于梁段数量多，梁段与梁段对接焊缝收缩量难以控制，其变化量积累起来数量大。所以梁段成桥工地焊接对其梁段总长的影响较大。本文重点介绍宜昌长江公路大桥钢箱梁工地焊接施工中，在钢箱梁长度的预控，跟踪修正，精确控制钢箱梁焊接成桥总长度等方面采取的一些关键工艺。     

桥门式起重机金属结构的静强度计算与分析

对桥门式起重机金属结构的静强度分析,提高对桥门式起重机的承受载荷的能力。提出一种基于结构抵抗变形能力测试和弹性模量屈服强度响应能力分析的桥门式起重机金属结构的静强度计算方法,首先进行了桥门式起重机金属结构的弹性荷载本构关系模型设计,采用动态曲率修正方法进行桥门式起重机的弹性模量屈服强度响应测试,实现对起重机金属结构的静强度准确计算和拟合。仿真结果表明,采用该算法计算桥门式起重机静强度准确,对承受载荷估计精度较高,提高了起重机的荷载能力。     

热轧桥壳用钢BQK580钢板的研制开发

根据汽车桥壳用钢使用特点进行了成分和工艺设计。结合桥壳钢技术要求,分析了化学成分、工艺参数、金相组织对桥壳钢性能的影响,在热轧1750生产线研制开发了桥壳用钢BQK580。     

汽车桥壳用DQK415钢板的工艺研究

根据汽车桥壳用钢的使用特点进行成分设计,对铌、钛微合金钢在2 700 mm中板轧机上进行不同控轧控冷工艺的试验研究;结合桥壳钢的技术要求,分析化学成分、工艺参数、金相组织对桥壳钢性能的影响。确定合理的化学成分及工艺制度,研发出了屈服强度415 MPa级热轧冲压桥壳专用钢板。     

对在用起重机吊钩的检查及检验

为保证起重机吊钩的安全使用，防止发生吊钩坠落事故，需完善吊钩的检查和检验。介绍了对使用中的桥、门式起重机所用吊钩的检查和检验。     

Concrete Bridge Demolition Methods and Equipment

The transportation infrastructure in the U.S. is maturing rather rapidly, leading to a shift of work and expenditures from new construction to maintenance, rehabilitation, retrofit, or even replacement of the existing system. Therefore, bridge demolition is increasingly becoming an important issue, as more bridges reach their service life and require rehabilitation or replacement. Furthermore, as the capacity of bridges and highways are reached, partial or total removal of bridges become necessary to allow for widening of the highway underneath the bridge or for widening the bridge itself to increase the capacity of the transportation system. Therefore, this paper addresses an important topic. It first discusses the factors affecting the selection of a bridge demolition technique. Then, the paper lists and describes a number of techniques and equipment employed in concrete bridge demolition along with discussions of actual bridge demolition projects and experiences. Finally, the paper outlines and discusses some safety issues related to the bridge demolition process.     

Rating and Reliability of Existing Bridges in a Network

Currently, the load rating is the method used by State DOTs for evaluating the safety and serviceability of existing bridges in the United States. In general, load rating of a bridge is evaluated when a maintenance, improvement work, change in strength of members, or addition of dead load alters the condition or capacity of the structure. The AASHTO LRFD specifications provide code provisions for prescribing an acceptable and uniform safety level for the design of bridge components. Once a bridge is designed and placed in service, the AASHTO Manual for Condition Evaluation of Bridges provides provisions for determination of the safety and serviceability of existing bridge components. Rating for the bridge system is taken as the minimum of the component ratings. If viewed from a broad perspective, methods used in the state-of-the-practice condition evaluation of bridges at discrete time intervals and in the state-of-the-art probability-based life prediction share common goals and principles. This paper briefly describes a study conducted on the rating and system reliability-based lifetime evaluation of a number of existing bridges within a bridge network, including prestressed concrete, reinforced concrete, steel rolled beam, and steel plate girder bridges. The approach is explained using a representative prestressed concrete girder bridge. Emphasis is placed on the interaction between rating and reliability results in order to relate the developed approach to current practice in bridge rating and evaluation. The results presented provide a sound basis for further improvement of bridge management systems based on system performance requirements.     

Routing and Permitting Techniques of Overweight Vehicles

Overweight vehicles require permits to cross the highway bridges, which are designed for “design load vehicles” (prescribed in the national standards). A new, fast, and robust method is presented for the verification of bridges, which requires minimal input only: the axle loads, axle spacing, the bridge span(s), and the superstructure type. The bridge can be a single or a multispan girder, an arch bridge, a frame structure, or a box girder. The overweight vehicle may operate within regular traffic or it may cross the bridge at a given lane position while other traffic is prohibited on the bridge. The method is illustrated by numerical examples for deck-girder bridges and for a box girder.     

Aesthetics and Philosophy in Bridge Design in Japan

This paper investigates the background of current trends in bridge design in Japan in the context of common design practice, which distinguishes architecturally, industrially, and structurally led designs. Because the philosophy of engineering design has not been recognized outside the rational philosophies of structural mechanics, this paper introduces a method of design and evaluation that is based on the application of architectural philosophies for bridge design. While current criticism is basically devoted to the evaluation of structural and visual qualities of bridges, the method illustrated by the case study of Japan Bridge, includes the aesthetic and ideological analysis of bridge design, which, like the analysis of building design, draws on subjective design concepts. Unlike in the conventional critical apraisal of bridge design, this method allows for the reintegration and evaluation of the structural and architectural values of bridges. Considering the complexity of comtemporary Japanese bridge design, landscape-oriented, structure-oriented, preservation-oriented, thematic, and symbolic trends in bridge design have been distinguished. Rediscovering philosophy in bridge design can be an effective way to invoke a wider response to the creativity of bridge designers.     

Implications of Design Assumptions on Capacity Estimates and Demand Predictions of Multispan Curved Bridges

The paper presents a detailed seismic performance assessment of a complex bridge designed as a reference application of modern codes for the Federal Highway Administration. The assessment utilizes state-of-the-art assessment tools and response metrics. The impact of design assumptions on the capacity estimates and demand predictions of the multispan curved bridge is investigated. The level of attention to detail is significantly higher than can be achieved in a mass parametric study of a population of bridges. The objective of in-depth assessment is achieved through investigation of the bridge using two models. The first represents the bridge as designed (including features assumed in the design process) while the second represents the bridge as built (actual expected characteristics). Three-dimensional detailed dynamic response simulations of the investigated bridge, including soil-structure interaction, are undertaken. The behavior of the as-designed bridge is investigated using two different analytical platforms for elastic and inelastic analysis, for the purposes of verification. A third idealization is adopted to investigate the as-built bridge’s behavior by realistically modeling bridge bearings, structural gaps, and materials. A comprehensive list of local and global, action and deformation performance indicators, including bearing slippage and inter-segment collision, are selected to monitor the response to earthquake ground motion. The comparative study has indicated that the lateral capacity and dynamic characteristics of the as-designed bridge are significantly different from the as-built bridge’s behavior. The potential of pushover analysis in identifying structural deficiencies, estimating capacities, and providing insight into the pertinent limit state criteria is demonstrated. Comparison of seismic demand with available capacity shows that seemingly conservative design assumptions, such as ignoring friction at the bearings, may lead to an erroneous and potentially nonconservative response expectation. The recommendations assist be given to design engineers seeking to achieve realistic predictions of seismic behavior and thus contribute to uncertainty reduction in the ensuing design.     

Dynamic Response of Suspension Bridge to High Wind and Running Train

A framework is presented for predicting the dynamic response of long suspension bridges to high winds and running trains. A three-dimensional finite-element model is used to represent a suspension bridge. Wind forces acting on the bridge, including both buffeting and self-excited forces, are generated in the time domain using a fast spectral representation method and measured aerodynamic coefficients and flutter derivatives. Each 4-axle vehicle in a train is modeled by a 27-degrees-of-freedom dynamic system. The dynamic interaction between the bridge and train is realized through the contact forces between the wheels and track. By applying a mode superposition technique to the bridge only and taking the measured track irregularities as known quantities, the number of degrees of freedom of the bridge-train system is significantly reduced and the coupled equations of motion are efficiently solved. The proposed formulation is then applied to a real wind-excited long suspension bridge carrying a railway inside the bridge deck of a closed cross section. The results show that the formulation presented in this paper can predict the dynamic response of the coupled bridge-train systems under fluctuating winds. The extent of interaction between the bridge and train depends on wind speed and train speed.     

部分斜拉桥的发展及静力性能分析

部分斜拉桥是近年来出现处于梁桥与传统斜拉桥之间新的桥梁结构型式．本文分析和介绍了它的产生、发展以及静力性能，并研究了影响其静力行为的两个重要参数——主梁无索区长度和边跨与中跨比，显示这些因素对主梁和主塔的挠度、内力等影响。     

武钢厂前大道跨线桥检测分析与病害整治

武钢厂前大道跨线桥经过50年的运行,桥梁结构产生病害,出现缺陷,桥梁状态的劣化严重影响到桥梁正常使用.通过对桥梁结构的检测分析和技术状态的评定,研究其病害机理与防护对策,并及时防范和予以整治,使桥梁的使用寿命得以延长.     

桥式起重机大梁与端梁开裂分析及处理

桥式起重机是大质量物品的重要运输工具,在实际工业生产中的有着广泛的应用,在多种因素的影响下桥式起重机大梁与端梁时常有开裂的情况发生。桥式起重机大梁和端梁的主要结构形式是焊接结构,开裂最容易出现在焊接部位。在本次研究中以某冶炼厂现役桥式起重机为调查对象,采用测量法和现场调查法结合有限元方法对桥式起重机频繁出现的裂缝进行研究,对桥式起重机的大梁和端梁结构进行了应力测试,并结合实际开裂情况,从材料、制作工艺、焊缝布置、大梁和端梁疲劳受力状况等原因进行了分析,找出了导致焊缝开裂的原因,同时探讨了焊缝的修补方法和对大梁与端梁的加固措施,并经实践论证,此处理方法有效地延长了桥式起重机的寿命,有效减少了安全隐患。