【作者】 胡成；

【导师】 曹双寅； 李延和；

【作者基本信息】 东南大学 ， 桥梁与隧道工程， 2006， 博士

【摘要】 混凝土结构的加固技术是目前国内外土木工程界研究的热点问题。与发达国家相比,我国的建筑物加固与改造技术的总体水平还不高,尚有许多问题亟待解决,其中钢筋混凝土双向板作为最普通的结构构件,对其加固技术的研究和创新一直是国内外学者关注的一个热点课题。众所周知,在已有的许多加固技术中,在钢筋混凝土构件的受拉区表面粘贴薄钢板或纤维增强聚合物FRP(Fiber Reinforced polymer)片材是一种业已证明的有效加固方法,它能显著提高结构构件的承载力和变形刚度、改善结构构件的抗裂性能;与外贴加固法相比,体外预应力加固则可以通过控制张拉吨位来主动消除新增加部分的应力滞后,使结构加固后新、旧两部分能够更好地协同工作而成为一个有机的整体,因而体外预应力加固技术也被认为是目前最有效的结构加固技术之一。近十年来,在钢筋混凝土双向板的加固技术研究和工程实践中,在外贴加固法的应用和研究方面都已做了一定的工作,但怎样利用双向板的受力特点,将一般是各向同性的钢筋混凝土双向板通过外贴单向钢板条以形成新的正交异性板来达到加固目的,以及又如何将体外预应力加固技术应用在双向板的加固实践中,近年来虽然有一些工程的应用实例,但在这两方面的系统研究国内外都少有涉及。为此,本文着重对粘贴单向钢板条和单向张拉体外预应力钢筋加固钢筋混凝土双向板的受力性能进行较为深入的试验研究和理论分析。主要研究内容如下:1.变刚度双向板的内力和变形钢筋混凝土双向板在板底粘贴一块钢板后,板的刚度发生了变化,成为了变刚度板。本文利用弹性理论分析了粘贴单向钢板条后混凝土双向板中单宽板条梁的受力特点,研究指出由于双向板中扭矩的存在减少了板条梁的弯曲变形,钢板条承受的正应力和剪应力和板条梁中混凝土截面所承受的正应力和剪应力一起构成了外荷载作用下板条梁的截面正弯矩和侧面扭矩,粘贴单向钢板条降低了其横向板条梁所分配到的荷载比值,说明了单向粘贴钢板条加固双向板的工作机理。2.粘贴界面的应力分布采用考虑分布扭矩对界面应力影响的条带法,通过求解外贴钢板条加固双向板中单向板条梁微元的平衡方程,推导给出了界面粘结应力的计算公式,分析计算了粘结正应力和粘结剪应力的分布规律,并比较了双向板和单向板(梁)粘结应力的异同。3.双向板在板边弯矩和面内压力作用下的内力和变形本文首先采用能量法分析给出了双向板在板边分布弯矩和集中弯矩以及在板边的面内均布压力和集中压力分别作用时的挠度变形表达式,然后利用差分原理计算了各种荷载工况下双向板的内力分布,并用VB语言编制了求解双向板变形和内力的计算机程序,最后在分析计算实例的基础上说明了张拉体外预应力钢筋对双向板的加固作用机理。4.单向加固钢筋混凝土双向板的试验研究本文共完成了两类单向加固的试验研究工作,其一是具有8个试件的外贴单向钢板条加固钢筋混凝土双向板的室内模型试验,第二个是包括5个试件的单向张拉体外预应力钢筋加固钢筋混凝土双向板的现场足尺原型试验。试验研究的主要内容为:单向加固板的裂缝形态和破坏形态,加固板的变形和抗裂性能,加固板的极限承载力,体外预应力钢筋的应力增量,外贴钢板条和体外预应力更多还原

【Abstract】 Study on strengthening-techniques in Concrete structure is popular in civil engineering. Compared with developed countries, the level of our Strengthening-techniques isn’t in advance, many problems need to be solved. For example, to be the most ordinarily structure member, the strengthening-techniques in RC two-way slab has been the hotspot problem.Of all the kinds of strengthening-techniques, strengthening reinforced Concrete structure using Fiber Reinforced Polymer(FRP) or steel plates has become widely accepted, its ultimate capacity and deformation stiffness are widely increased, its cracking-behavior is also improved. Compared with bonding FRP or steel plates, the external prestressing method has many advantages over the tradition ones, such as controlling stress actively and eliminating stress lag. These days, some studies on RC two-way slabs strengthen with bonding FRP or steel strips have been undertaken, but less work has been done in achieve its strengthening-aim by changing two-way slabs’isotropy behaviour through bonding one-way steel strips, at the same time, less work has been pursued in strengthening RC two-way slabs by using the external prestressing method. The following paper deals with this subject through model test, theory analysis and numerical simulation.The main content and achievement of this paper are briefly summarized as follows:1. The internal force and deformation of stiffness-changing two-way slabRC two-way slab is changed to been stiffness-changing slabs by bonding one-way steel plates, the elastic theory has been used in analysis the two-way slabs strengthen with bonding one-way steel strips. The research revealed that torsion reduced the bending deformation of slab-beam, the bending moment and side torsion of slab-beam are made up of the normal and shearing stress in cross section of steel plate and concrete slab-beam, bonding one-way steel strips reduced the load ratio of the slab-beam in its landscape orientation , the one-way strengthening method is in effect.2.The distribution of bond stressThe strip method is used to analysis the balance equation of one-way slab-beam in two-way slab by taking into account the influence of torsion, the bond normal stress and bond shearing stress are calculated, the difference of them in two-way slab and one-way slab is also compared.3.The internal force and deformation of two-way slabs under bending moment in slab sides and compressive stress in faceBy using of the Energy method, the calculating expressions of deformation of slabs under distributing or focus bending moment in slab sides and distributing or focus compressive stress in slab face are also presented. The difference theory is also used to analysis the distributing of internal force under all kinds of load conditions, VB is used to workout the calculating program, the validity of external prestressing in strengthen two-way slabs was proved by a example.7. Experiment study更多还原