预应力筋的理论伸长量精确计算

结合工程实例，介绍了预应力筋理论伸长量分段计算的方法，总结了影响理论伸长量值的几种因素，以提高理论伸长量的计算准确性，有效控制预应力施工。     

后张法施工中预应力筋延伸量计算及影响因素

简单分析了后张法预应力张拉施工中预应力筋的不同施工次序所应考虑的施工风险,介绍了规范中关于预应力筋张拉伸长量理论值的2种给出途径。详细介绍了预应力筋的实测伸长量的计算,包括伸长实测值和应该扣除的伸长部分。最后讨论了千斤顶安装位置对张拉力的影响及一端张拉另一端补拉的效果分析。     

非对称预应力束张拉理论伸长量计算

结合工程实例,介绍了预应力筋的理论伸长量计算方法,通过计算预应力筋摩阻损失,确定了非对称布置双端张拉预应力筋应力最小点,解决了该种形式预应力筋理论伸长量计算问题。     

谈谈后张预应力钢筋胀拉

现场生产的预应力钢筋混凝土构件一般采用后张法,其预应力筋用Ⅳ级钢虽有用钢量少的优点,但因Ⅳ级钢供应紧张,规格不齐,锚具加工比较麻烦等原因故而目前Ⅱ级钢仍被广泛地作预应力筋。本文就以Ⅱ级钢粗钢筋为预应力筋的钢筋混凝土屋架,对预应力筋伸长值测定,张拉程序等问题作些探讨。众所周知,张拉预应力钢筋时要测定预应力筋的实际伸长值,实际伸长值与计算伸长值如相差不多,即认为张拉符合要求。这     

后张法预应力筋伸长量的计算

介绍了预应力筋张拉伸长量的规范算法，针对比较繁琐的由直线、曲线混合组成预应力筋的伸长量的计算，提出一种简便、精确的计算方法，具有一定的参考借鉴价值。     

预应力筋伸长量的精确计算与量测

预应力混凝土结构在桥梁工程中广泛应用,准确计算预应力筋的理论伸长量和量测实际伸长量是控制张拉施工质量的基础。根据材料力学理论和目前的施工技术,结合本工程实例,比较了2种不同伸长量计算方法的精度,并分析了影响伸长量量测的误差的因素。     

曲线预应力钢绞线理论伸长值分段计算探讨

本文通过以20m预应力空心板的钢绞线的理论伸长值的计算为例，详细介绍了预应力筋在呈曲线分布时理论伸长值的分段计算方法，并通过与不分段计算理论伸长值的比较，得出了预应力筋在呈曲线分布时理论伸长值分段计算的重要性。     

体外预应力连续组合梁预应力筋拉力计算方法及全过程受力分析

对体外预应力钢-混凝士连续组合梁进行全过程受力分析时,需准确计算预应力筋的拉力,因此,对预应力组合梁中预应力增量及全过程受力分析的计算方法进行了研究.根据梁体自身在荷载作用下的变形条件,采用几何方法给出了各种布筋形式下体外预应力筋伸长量的计算方法;基于共轭梁法,并考虑连续组合梁内力重分布,采用迭代法得到了预应力连续组合...     

后张法预应力筋施工控制

结合某高速公路箱梁的具体施工工艺,对预应力筋伸长量校核作了介绍,探讨了预应力张拉的两种张拉程序,分析了预应力筋张拉实际伸长值的测量和允许误差,以取得准确的预应力值,保证预应力构件的质量。     

后张法预应力筋理论伸长量精确计算方法探讨

对现行的JTJ041—2000公路桥涵施工技术规范预应力筋理论伸长量计算方法进行了理解与补充，并对由直线与曲线组成曲线筋张拉理论伸长量分段精确计算公式进行了推导，并提出了计算注意事项。     

表面油脂对环氧喷涂钢绞线影响分析及其应用

通过对五种不同情况下的环氧喷涂钢绞线张拉强度对比试验分析,研究环氧喷涂钢绞线表面油脂对其与水泥砂浆握裹力的影响。经过试验研究表明:环氧喷涂钢绞线表面油脂对其水泥砂浆握裹力有一定影响,表面油脂较多的钢绞线握裹力较差,而表面油脂清洗干净的钢绞线握裹力较好;在无粘结预应力筋张拉的实际过程中,应该将环氧钢绞线表面油脂清洗干净,以免影响无粘结预应力的张拉性能。     

波形钢腹板对箱梁预应力效率的影响

为研究波形钢腹板对组合梁预应力导入效率的影响,推导波形钢腹板PC组合梁预应力导入效率的计算公式,并结合有限元方法,对不同几何参数的波形钢腹板PC组合梁的预应力导入率进行模拟研究。结果表明,波形钢腹板虽然对组合梁预应力效率有一定影响,但总的来说影响不大。在波形钢腹板不同几何参数中,对预应力效率影响最大的是波高,其次是波长。波形钢腹板厚度、波形钢腹板高度对预应力效率几乎没有影响,在波形钢腹板PC箱梁设计中可以不考虑二者的影响。     

中厚板高强度螺栓连接性能试验研究

本文针对中厚板高强螺栓连接，对超长螺栓预拉力的维持能力，厚板高强螺栓抗滑移系数及厚板多栓接头螺栓预拉力的变化分别进行了试验研究．获取了可靠的数据．为中厚板高强螺栓连接应用提供了有价值的参考．     

采用体外预应力技术加固钢筋混凝土梁

介绍了采用体外预应力技术加固钢筋混凝土梁的加固设计原理,阐述了体外预应力加固的具体方法,并结合具体的工程实例提出了设计建议,以推广该结构加固技术的应用。     

Magnetoelastische Spannkraftmessung in Bauwerken

Magnetoelastic Measurement of Prestressing Force in Civil Structures The knowledge of the tensile force of prestressing steel elements and its reliable and non‐destructive determination are of essential importance for the assessment of the structural health condition of prestressed concrete structures and tie‐back systems in terms of structural safety, serviceability and durability. For the evaluation of the prestressing force in steel tension members, the measurement technique presented in this contribution is using the magneto‐elastic effect (ME‐effect) of ferromagnetic materials. This effect describes the reverse‐proportional correlation between the mechanical stress and the magnetic properties of ferromagnetic materials. The cylindrical coiled sensors pushed over the tendon and the measuring device developed and practically optimized at the iBMB/MPA of the TU Braunschweig enable a fast and reliable measurement of the prestressing steel force after an initial calibration. In this contribution first the state of the art of prestress measurement techniques for steel tension members is presented. Afterwards, the ME‐measuring method with the basics and merits of magneto‐elastic prestressing force identification is shown. Further recent research results as well as several building applications will be discussed.     

Flexural behavior of steel I-beam prestressed with externally unbonded tendons

The external post-tensioning technique has been commonly used in the construction field because it facilitates the analysis of structures and is widely applicable for many types of structures. In this paper, the flexural behavior and strengthening effect of a bridge were studied using a steel I-beam that had been externally prestressed with unbonded tendons. Eleven steel beams were fabricated and tested in terms of the tendon type, the amount of tendon or prestressing force, the installation of a deviator, and the embedment of a draped tendon. The results show that the externally prestressing method creates a stiffer steel beam when the proper amount of prestressing force is applied and when detail techniques are appropriately combined.The experimental results were compared to a theoretical solution in order to verify whether the external post-tensioning method is useful for strengthening a steel bridge and whether it is applicable in the construction field.     

部分预应力混凝土框架计算

为解决工程中日益增多的大跨度框架结构设计，对部分预应力单跨框架的计算做了较详细的介绍，主要内容有曲线预应力筋的布置、预应力损失和预应力引起的内力计算以及抗裂验算和挠度验算等。     

采用体外预应力加固简支实腹钢梁的设计计算

体外预应力加固方法是提高钢梁承载能力、改善其受力性能的一种简单易行的方法。本文对体外预应力加固简支实腹钢梁时体外预应力筋的线形布置、预应力损失以及内力增量的计算和体外预应力筋截面面积的确定进行了分析 ,并且对加固后钢梁的设计计算进行了研究 ,最后通过一实例进行了设计计算     

Multi-stepwise thermal prestressing using a cover-plate in steel structures

This paper introduces an innovative prestressing method for steel structures utilizing a multi-stepwise thermal prestressing method (M-TPSM). The proposed prestressing method is founded on a simple concept of thermal expansion and contraction of steel. A cover-plate, a high strength steel cover-plate used as a post-tensioning member in this method, is heated by electrical heaters before it is attached to the main member. After the cover-plate is attached to the main member by using high tension bolts at several points or by welding, the electromagnetic induction heaters are removed, and the resulting contraction force of the cover-plate induces eccentric axial forces to the main member. In this study, a fundamental investigation involving analytical and experimental study is carried out to evaluate the feasibility of the M-TPSM for steel structures. Also, static loading tests were performed on the rolled beam specimens for assessment of the behavior of the steel beam prestressed with M-TPSM.     

拉力型和压力型预应力锚索受力分析及工程应用

根据拉力型、压力型预应力锚索结构特征，本文将拉力型预应力锚索抽象为在假想滑动面处受一个集中力P，将压力型预应力锚索抽象为在锚索孔底处受一个集中力P。工程中一般假想滑动面或锚索孔底距岩土体表面较远。基于以上假定和工程条件把预应力锚索归结到空间体内一点受集中力Kelvin问题。文中引用Kelvin应力解求得了拉力型预应力锚索钢绞线侧壁、锚索孔壁剪应力τ沿轴向分布，求得了压力型预应力锚索孔壁剪应力汲正应力σ沿轴向分布。 根据本文结果：建议岩体中拉力型预应力锚索设计时应以钢绞线与注浆体之间粘结强度作为设计依据。建议岩体中压力型预应力锚索在受力端增加一段钢管改进成压力局部分散型预应力锚索。建议土体中压力型预应力锚索采取孔底扩孔改进成扩大头式压力型预应力锚索。