FRP加固钢筋混凝土桥墩基于性能的指标量化

将基于性能设计的思想与FRP加固钢筋混凝土桥墩相结合,对国内外98个FRP加固钢筋混凝土桥墩试件的位移角进行统计分析,给出了划分性能水平的位移角限值。对FRP加固钢筋混凝土桥墩的屈服位移角dy和极限位移角du进行单因素分析。讨论了位移角与纵筋率ρs、体积配筋率ρv、混凝土强度fc、轴压比n、剪跨比λ、及FRP特征值λf之间的关系,将显著影响位移角的因素:纵筋率ρs、轴压比n、FRP特征值λf考虑到量化当中,并给出修正公式。     

桥梁墩柱混凝土外观质量问题分析及对策

分析了混凝土表面泌水起砂、气泡、露筋、裂缝、外观颜色不一致等墩柱外观质量问题产生的主要原因,并从施工模板和施工混凝土两方面提出了墩柱外观质量的控制措施,以确保墩柱施工的外观质量。     

Mathematical model of RC banded column behaviour

This paper presents a mathematical model of banded columns and theoretical analysis of factors influencing their behaviour. The equations for the real load–carrying capacity are given. The results of the theoretical behaviour are compared with experimental results.     

砖混结构中钢筋混凝土构造柱、圈梁对抗震的作用

本文对砖混结构构造柱和圈梁从规范规定出发,通过构造柱和圈梁在砖混结构中的不同作用,结合“5．12”汶川大地震对构造柱和圈梁不规范的设计或施工造成砖混结构房屋的不同损坏情况,进行粗略分析构造柱和圈梁对砖混结构抗震所起到的主要关键作用,供今后的砖混结构的设计、施工有所参考。     

Recent developments in optimal reinforcement of RC beam and column sections

Recent advances in approaches to the design of reinforced concrete sections have culminated in a theorem of optimal (minimum) sectional reinforcement. This theorem is articulated on the basis of patterns observed in the optimal reinforcement of rectangular sections, obtained with a new approach for the analysis and design of reinforcement. Using the hypotheses for ultimate strength design sanctioned by ACI 318-05 (2008), the minimum total reinforcement area required to provide adequate resistance to axial load and moment is shown to occur for particular constraints on longitudinal reinforcement area or distributions of strain. These constraints are identified along with the solutions for minimum total reinforcement area. Optimal reinforcement may be selected from among the potential solutions identified by the theorem. An example illustrates the application of the theorem to the design of a reinforced concrete cross-section. Implications for teaching and practice of reinforced concrete design are discussed.     

钢筋混凝土刚架拱桥荷载试验及仿真分析

对混凝土刚架拱桥进行了荷载试验及检测数据分析,并运用大型有限元程序Midas进行了仿真分析,通过多种工况下桥梁变形和内力实测值的比较、实测动力学曲线的频谱分析,以充分了解桥梁结构的力学性能,为桥梁的安全使用提供依据。     

考虑粘结滑移的RC柱抗爆性能影响因素分析

在考虑粘结滑移影响的前提下,对不同的纵筋配筋率、箍筋间距和轴压比的RC柱在典型爆炸荷载作用下进行了抗爆分析,以最大程度的提高RC柱的抗爆性能。     

钢筋混凝土葵花拱受力性能分析

迎宾大桥是一座钢筋混凝土葵花拱。本文采用通用有限元程序,对其受力性能进行了分析。计算结果表明,迎宾大桥主桥的设计满足规范要求,但在拆除主拱的满堂架时,系杆张拉力增加很快,为此进行了计算分析,结果表明通过施工工序设计的调整可满足要求,计算结果可供同类型桥梁参考。     

大跨径混凝土拱桥拱上立柱接头施工质量控制

阐述了广西柳州市三江县中山大桥拱上立柱预制与现浇接头施工,介绍了接头模式、预制及现浇立柱端头处理、接头对接、接头混凝土施工控制要点,结合实际提出了对缺陷处理的措施,从而为实际工程施工积累经验。     

运营桥梁独柱墩加固工程支座安装施工技术

结合杭长高速公路泗安枢纽3号桥独柱墩加固工程的施工,详细介绍了运营通车情况下独柱墩现浇箱梁桥增设支座加固施工的工艺和方法,总结了施工中的控制要点及注意事项,为今后类似工程施工提供了参考。     

桥梁墩柱外观混凝土施工新技术

结合模板衬里铺垫材料、电渗排水成型技术、外加剂涂刷工艺,汇总介绍了保证桥梁墩柱混凝土结构外观质量的方法。提升桥梁工程混凝土外观质量,除了提升施工管理,还应积极应用新技术、新材料。     

方钢管混凝土柱受力性能研究

以含钢率、长细比、材料强度为主要参数,利用有限元软件ANSYS对方钢管混凝土柱在轴力和水平荷载作用下进行了非线性有限元计算,研究表明：方钢管混凝土柱达到极限荷载后,仍表现出良好的延性和后期变形能力,其受力性能明显优于空钢管试件和钢筋混凝土试件。     

钢筋混凝土圆柱等效阻尼比及在桥梁抗震分析中的应用

基于对50根弯曲破坏钢筋混凝土圆柱低周反复试验结果的分析,建立了完整滞回环的数学表达式并推导得出等效阻尼比计算模型;以双柱墩桥梁为例,说明了建立桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比关系的方法。研究表明,完整滞回环数学表达式较好地反映了弯曲破坏钢筋混凝土圆柱的滞回特性,得到的等效阻尼比模型计算结果与试验结果符合较好;采用建立的桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比的关系进行pushover分析更能反映实际情况。采用等效阻尼比模型算得的目标位移与基于Rosenblueth模型和Kowalsky模型算得的位移之间存在较大差距。     

Spalling of concrete cover of cyclically loaded columns and fire behaviour of columns with concrete spalling

Fire following an earthquake is a threat to seismically damaged structural members with spalling of concrete cover. To evaluate the fire behaviour of the damaged members, it is important to determine the spalling length and thickness reasonably. In this paper, 16 columns were cyclically loaded to check their concrete cover spalling features. Based on the test results and PEER’s database, formulas are proposed for flexure-critical rectangular columns to approximately evaluate the spalling length and thickness of the columns’ concrete cover. Then, thermal and mechanical performance of the damaged columns in fire is numerically studied. It is found that: (a) the maximum spalling length generally increases with the increasing column’s drift ratio and axial load ratio, but it does not exhibit monotonic trend with the change in the shear span ratio and volumetric transverse reinforcement ratio; (b) the ratio of the equivalent spalling length to the maximum spalling length generally increases with the increasing column’s drift ratio and axial load ratio; and (c) fire endurance of the damaged column calculated using the equivalent model is 7–18% higher than that using the realistic model, and a discounted factor of .8 is recommended for the former.     

高寒地区桥梁墩柱混凝土的生产施工

结合工作实践，就海公铁路桥梁墩柱冬季混凝土施工经验和体会进行了论述，具体对混凝土冬季施工准备工作、施工方法及施工中应注意的问题作了总结，以指导工程实践。     

钢筋混凝土柱的爆炸动力响应分析

通过采用ANSYS／LS-DYNA软件对爆炸荷载作用下考虑周围构件约束的钢筋混凝土柱进行非线性有限元分析,研究不同炸药当量,爆炸距离,轴压比等对其抗爆性能的影响,提出一种新的简化模型,为今后进行加固提供了初步依据。     

钢管混凝土系杆拱桥成桥静载试验分析

以苏北运河大桥为例,通过对该桥进行静载试验和桥梁专用程序分析,依据试验各工况应变和挠度的理论值和实测值,对该桥做出了客观的评价,并得出相关的结论.     

厦漳跨海大桥南汊斜拉桥索塔中塔柱主动横撑的设计计算

本文介绍了厦漳跨海大桥南汊斜拉桥索塔施工中,为消除中塔柱倾斜塔柱根部混凝土的不良应力状态所采用的主动横撑结构的构造特点,以及考虑了施工因素的该结构的设计计算方法,确保中塔柱根部在施工过程中不开裂。该计算方法对类似工程具有一定的指导意义。     

Proportioning of reinforced concrete column sections

Relatively simplistic recommendations are widely available for the preliminary sizing of reinforced concrete columns. A simple, more precise approach is developed herein. The neutral axis depth and reinforcement required to provide a desired resistance to axial load and moment was determined analytically for the common case of symmetrically distributed reinforcement. Readily available solver routines are used to determine section dimensions required to provide the desired axial and flexural strength, for a desired reinforcement ratio. The approach is illustrated for two examples, including a case in which independent load combinations cause bending about each principal axis of the section.     

Tests of RC beams under a moving load-evaluation of deformation work

The evaluation of the deformation work from the tests of the beams subjected both to the stationary (immovable), continuously increasing load up to the failure point and to the simulated moving load. The elastic part of the deformation work was found out by unloading and the irreversible part was taken for the dissipated part of energy.