frp毕业论文

Big span structure of FRP network analysis and forecastAbstract: this article will introduce a new big span structure, FRP netting structure. In a FRPWWS structure, high intensity of FRP materials like Chinese bamboo weaving of bamboo is a planar formation in the mesh network, the periphery of the structure of the anchorage in a JuanXing beam, the structure of the center for the anchorage netting another within the parameters. Threads on knitting production structure on the initial stress and advance within the parameters of surface movement to meet additional tension of various load resistance. Due to the high FRP materials, materials - weight ratio of this new form for some big span structure of space construction provides an attractive option, the span longer than conventional structural materials building span. In this paper, firstly introduces the basic structure of FRPWWS simple steps, then layout and construction illustrates three basic types of weaving structure, but also put forward some changes this way. This paper introduces a simple mechanical model for the mechanical deformation of FRP single, also gives an example of the structure of the finite element analysis process.A, introductionFRP is a new type of structural materials, in recent years in civil engineering research is very active. Because he has some good performance, such as corrosion, light weight, high strength, good fatigue resistance and low cost of maintenance, it was thought to be built in new century building long-span structure of ideal, but it is in some aspects of the traditional mechanical properties and structure of the material or have obvious difference, such as its various heterosexual phenomenon. Due to the uniqueness of FRP materials, the effective use of FRP materials and traditional building materials can span, it is necessary to study the new big span structure. Maeda et al. (2002) is built with the idea of FRP materials 5000 metres of suspension bridge spanIn this paper, the FRP netting structure of a kind of brand-new big span structure. This new structure form in a large span to try to effectively use the roof of FRP material performance. In FRPWWS structure, high intensity of FRP compiling Chinese traditional bamboo as the same are woven into a bamboo plane mesh structure. This mesh structure parameters on the anchoring outside outside, the structure of the center and a smaller parameters used in anchorage ribbon. Figure 1 is a small FRPWWS structure model. "Weave" to ensure the smooth of FRP materials at first, to the extent of FRP weave on the prestressed concrete. Then, through the surface movement within the parameters of FRP netting, to pull through the process of prestressing tendons tensile or may have certain parameters including the gravity. Therefore, the FRP nets formed a with two parameters of large-span roofs, the FRP nets set stiffness can resist all sorts of load.FRPWWS structure similar to the cable networks or cable retinal structure: they constitute part is flexible, By stretching and caused to resist geometric stiffness of load. However, FRPWWS structure has its unique advantages: (1) the weight of FRP materials of low and vertically superior materials properties are effective utilization and transverse weaknesses, but not exposed in the structure of large span of FRP system is ideal, (2) the interchange of FRP plait will produce the huge damping, thereby strengthening structural anti-seismic capability, (3) there are rules of netting modelling makes surface is beautiful, (4) due to corrosion and gravity small installation and maintenance costs low.This paper introduces a simple FRPWWS structure of the basic layout and construction steps. The plane was roughly threads for three. Also puts forward some practical application examples of the FRPWWS space. Proposes a used nets in the mechanical model of single FRP. Finally describes a simple analysis of finite element method FRPWWS examples.Second, simple FRPWWS layoutA summary of FRP netting structure includes a FRP weaving, used to anchor the outer ring beam and inner beam and one for the extra gravity tension loading or a group of prestress reinforcement, as shown in figure 1.Nets are woven from article by FRP, also recommend guest FRP or other high-performance carbon fiber hybrid woven article. Carbon fiber FRP in recent years is widely applied to high strength concrete structure of new materials, it is usually made by extrusion, including fiber to 65%. By China and the Swiss production of two kinds of representative products performance data in table 1 shows prosperity.Due to the density of woven material, small and easy to be bent and uncoiling. A standard of performance such as table 1 similar carbon materials can withstand FRP greater than or equal to 400KN tension, while a 300m long this strip 70kg less weight. As compared to the same intensity has more than 300m wire 500kg weight.These woven article according to certain spacing is arranged in an appropriate form of plane. One of the most simple weaving method is a belt, and the other by vertical band, to make up like a fabric of net surface. This type of netting structure can see figure 2 partial screenshots. But in most cases, the number of under-colunm crossing-beam in between each other and the Angle, is the main measure of netting style; Every two ribbon to 90 ° fellowship as shown in figure 3 (a), three little is 60 ° belt in the intersection, as shown in figure 3 (b), as shown in figure 3 (c) and the four ribbon 45 °. At intersections, when fully forming available to all the attached agglutinate FRP interoperability or no adhesion between which can slide freely. In the example, behind will introduce to the static friction between the weaving of the stiffness and static load under dynamic loading sliding friction can consume the kinetic energy大跨度FRP网架结构的展望和分析 摘要：本文将会介绍一种新的大跨度结构，FRP织网结构。在一个FRPWWS结构中，高强度的FRP材料条像中国竹席中的竹片一样被编织在一起形成一个平面网，这个网状结构的外围锚固在一个圈形的梁上，结构的中心处还有一个用于锚固织网的内圈梁。织网结构靠编织生产时的初步预施加应力和内圈梁面外运动引起的附加张力调整来抵抗遇到的各类荷载。由于FRP材料的具有较高的材料-重量比，这种全新的结构形式为一些大跨度的空间建设提供了一种具有吸引力的选择方案，该跨度长于用常规结构材料建筑的跨度。在本文中，首先介绍了简单的FRPWWS结构的基本布局和施工步骤，接着阐明了三种基本的织造结构，同时也提出了此类结构方式的几种变化。文中介绍了一个简单的力学模型用于单个的FRP条力学变形，也给出了一个实例结构的有限元分析的过程。 一、 引言 FRP是一种新型的结构材料，近年来在土木工程中的研究很活跃。由于他具有一些良好的性能，如抗腐蚀，重量轻，强度高，抗疲劳性好以及维修费用低，它被认为是在新世纪建造大跨度结构的理想建材，但是它在某些方面的机械性能与那些传统的结构材料还是有明显的区别，譬如它的各项异性现象。由于FRP材料的独特性，为了FRP材料的有效使用以及获得传统建材所不能及的跨度，有必要研究新型的大跨度结构。Maeda et al.(2002)就设想了用FRP材料建造跨度5000米的悬索桥。 本文提出了FRP织网结构结构，一种全新的大跨度结构形式。这种新的结构形式旨在试图在一个大跨度的屋顶中有效利用FRP材料的性能。在FRPWWS结构中，高强度FRP编制像中国传统竹席中的竹片一样被编织成一个平面网状结构。这个网状结构的外沿锚固在外圈梁上，结构的中心处还有一个较小的内圈梁用于锚固织带。图1所示既是一个小型FRPWWS结构模型。为保证进行“编织”时FRP材料条的平直，首先要对FRP编织条施加一定程度的预应力。然后，通过内圈梁的面外移动来拉动FRP织网，施加预应力的过程可以通过预应力筋拉伸或在内圈梁设一定的重力来达成。 因此，受拉的FRP网形成了一个带有两个圈梁的大跨屋面，该FRP网的集合刚度能抵抗各种荷载。 FRPWWS结构类似于索网或索网膜结构：他们的构成部分是灵活多变的；并且靠拉伸引起的几何刚度来抵抗各种荷载。然而，FRPWWS结构有其独特的优点：（1）FRP材料自重低且纵向上优越的材料性能被有效利用，而横向上的弱点却没有暴露出来，因此在超大跨度的结构中FRP系统是理想的；（2）FRP编条的交汇处会产生巨大的阻尼，从而加强结构抗风抗震能力；（3）有规则的织网造型会使表面比较美观；（4）耐腐蚀并且由于自重小安装和维护成本低。 本文详细介绍了一个简单的FRPWWS 结构的基本布局和施工步骤。织网的平面被大致的归为三类。同时提出了一些实际应用的空间FRPWWS的例子。提出了一个用于网中单一FRP条的力学模型。最后描述了有限元法分析一个简易FRPWWS的例子的结论。 二、 简单FRPWWS的布局 一个简易的FRP织网结构包括一张FRP编织网、用于锚固的外环梁和内环梁还有一个用于张紧的额外重力荷载或一组被施加预应力的筋，如图一所示。 网是由FRP条编织成的，也客人推荐使用碳纤维FRP或其他的高性能混杂纤维类编织条。碳纤维FRP是近年来被广泛应用于高强度混凝土结构的新型材料，它通常由挤压制造，含纤维比例达到65%。由中国和瑞士生产的两类代表产品繁荣性能资料可见表1。 编织条材料由于密度小而易被弯曲和盘绕。一根标准的性能如表1相似的碳纤维FRP材料可以承受大于等于400KN的拉力，同时一根300m长的这种长条重量少于70kg。作为对比同等强度的300m钢缆自重已经超过500kg了。 这些编织条按一定的间距被编排在一个合适形式的平面上。最简易的编织方法之一就是一根带子与经过的垂直的其他带子上下交错，来制造一个像织物一样的网面。这种类型的织网结构的部分截图可参看图2。但大部分情况下，编织条在交叉点处的数量和互相之间的角度，才是衡量织网样式的主要标准；每两根织带以90°相交如图3（a）所示，三条织带在一点呈60°相交如图3（b）所示，还有图3（c）所示的四条织带的45°相交。在交叉点处，当完全成型后可用附着粘合使FRP条全部互交或不进行粘合使其相互之间可以可以自由滑动。在后面的例子里，会介绍编织条之间的静摩擦有助于静荷载下的刚度而滑动摩擦可消耗动态荷载下的结构动能。

在我们平凡的日常里，越来越多的事务都会使用到保证书，保证书是保证者提出保证时使用的专用书信信或文字材料。我们应当如何写保证书呢？以下是我帮大家整理的承诺保证书10篇，欢迎阅读，希望大家能够喜欢。

尊敬的客户：

首先，感谢您选择我公司的产品。

我公司处成立以来，本着相互信任、互利合作、共同发展的理念，一直将产品质量定位为公司参与市场竞争的核心。

公司根据产品质量要求，建立了严密的质量管理体系。对与产品质量有关的所有环节进行严格控制与管理，建立了科学的检验规程，并对检验指标进行了量化，责任到人，确保公司持续稳定生产合格的产品。 公司从原材料严格把关，杜绝不合格品流入生产现场，并与供方建立良好的供求关系。

宏远电器有限公司建立了定期的员工质量培训制度，学习质量管理的新知识、新信息，树立每一个员工的质量意识，规范自己行为，小到一个螺钉、大到一台整机都做到一丝不苟、精益求精。质量保证部门建立了规范的检验规程，具备完善的检测手段，并严格按照规程检验，作好产品质量检测的每一个环节，不让一台不合格产品出厂。

在此基础之上，我们还为您做出如下的承诺：凡我公司所供产品，我们将按照双方签订的合同、技术协议等文件要求，做好产品售后服务工作，具体如下：

1、自贵公司使用我公司产品之日起，我公司将随时提供现场售后服务，保证及时、准确的处理现场故障；

2、在双方签订的合同、技术协议中规定的质保期内，用户在正常使用本产品时出现非人为损坏的质量问题，我公司提供保修；

3、在保修期内，以下情况将实行有偿维修服务；（1）由于人为或不可抗拒的自然现象而发生的损坏；（2）由于操作不当而造成的故障或损坏；（3）由于对产品的改造、分解、组装而发生的故障或损坏。

内蒙古一机集团宏远电器有限公司质量保证部

20xx年2月10日

我的孩子名叫，在小学/中学年级就读，为保证孩子上下学交通安全，我保证做到以下几点：

1、教育子女认真学习交通法规和交通安全知识，提高安全意识和防护自救能力时刻注意自己和他人的交通安全。

2、教育子女骑自行车、电动车应该遵守交通法规，不骑“病车”，不满12周岁的学生不在道路上骑车。

3、教育子女严格遵守行人应该遵守的交通法规，走路靠右行，不违章过马路，做到“一停二看三通过”、不向过往车辆抛掷石块等。

4、教育子女严格遵守乘车时应该遵守的'交通法规，上车时不拥挤、遵守“先下后上”规则，不将头手伸出窗外，不在车内嬉闹，下车时不急于过马路等。

5、教育子女严格遵守：四不“原则，即：不乘三证不全的车辆，不搭乘超载车辆，不搭乘车况不好的车辆，不搭乘驾驶员有问题的车辆。

6、教育子女不驾驶摩托车等机动车辆，不在公路上玩耍，时时处处注意交通安全。

7、家长接送孩子的车辆要经常检修，不违规超载，不违章驾驶。

8、严格遵守其他应该遵守的交通法规。

本保证书一式两份，学校和家长各留存一份。

学校负责人签字：家长签字：

年 月 日

根据《中华人民共和国建筑法》，《建设工程质量管理条例》《房屋建筑工程质量保修办法》经协商一致对《甘州区新墩镇花儿村居民委员会会所网架工程》签订工程质量保证书。

一、工程质量保修范围和内容：

承包人在质量保修期内，按照有关法律、法规、规章的管理规定和双方约定承担本工程质量保修责任。(主要包括本工程施工图的设计与安装)

保修范围包括：网架钢结构部分、屋面彩钢围护部分、FRP采光带。

二、质量保修期：

双方根据《建设工程质量管理条例》和有关规定，约定本工程质量保修期：

1、网架钢结构部分质保50年。

2、屋面彩钢围护部分质保5年。

3、FRP采光带质保3年。

以上三项因不可抗拒外界因素造成的质量问题除外，质量保修期自工程竣工验收合格之日计算。

三、质量保修责任：

1、属于质量保修范围和内容的项目，承包人应当在接到保修通知7日内实施保修。

2、发生紧急抢修事故的，承包人应当在接到事故通知后立即到达事故现场抢修。

3、对于涉及结构安全的质量问题，应当按照《房屋建筑工程质量保修办法》规定，采取安全防范措施，由设计单位或有相应资质等级的设计单位提出保修方案，承包人实施保修。

四、保修费用、保修费用由造成质量缺陷的一方承担。

本工程质量保证书由施工合同发包方、承包方、生产厂家在竣工验收时共同签署，其有效期至保修期满。

本工程质量保证书一式三份，发包方、承包方和生产厂家(设计单位)各执一份。附;设计单位设计资质证书及安装资质证书复印件。

发包方(公章)：签字：XXX

承包方(公章)：签字：XXX

设计单位及生产厂家(公章)：签字：XXX

20xx年XX月XX日

尊敬的单位领导：

在此我怀着深刻自责、内疚的心情向您递交这篇工作期间玩电脑的保证书，以深刻反省我工作期间玩电脑的行为，向您表示深深的愧疚与歉意。

回顾错误，我于20xx年12月9日下午工作期间多次去了车间主任办公室玩电脑。以至于我严重地耽误了工作，没有能够较好地在自身办公室值班，导致了一些顾客前来办事没有能够办成。

这次由于一些私人的事情，网虫上脑，自以为有点小聪明，解开了公司的电脑密码，偷偷用办公室人员的电脑上网，结果被人当场抓住。

面对错误，我感到非常愧疚。这样的错误，导致了相当的不良影响。此次错误，也充分暴露出我自身存在工作觉悟松懈、思想散漫、行为放任自由等缺点与不足。为此，我觉得很愧疚于领导，很愧疚于同事，非常对不起大家。

特此，我在此向您做出深刻保证：从今往后，我没有事情就不再去往车间主任办公室，没有合理需要也不再触碰那台办公电脑了。

致河南______集团有限公司：

我公司参加了贵公司组织的郑州市二七区城中村改造_____项目b7-1标段建设施工招标活动，并且于20xx年___月___日与贵公司签订了编号为_____________ 的《建设工程施工合同》。我公司已经完全了解该合同之内容并无任何异议，特此不可撤销地和无条件地做出如下承诺保证：

1、我公司自愿向贵公司提供保证，以我公司的企业信誉、企业名下所有资产保证全面履行和完成合同项下的义务以及由签证变更和合同修改可能引起的需要我公司适时完成的工作。

2、如果我公司不按合同约定全面履行义务，我公司将按照合同约定和法律规定承担相应违约责任和赔偿责任，贵公司为维护合法权利而支付的费用亦由我公司承担。

3、在合同期间，我公司具备连续施工的资金能力。若我公司出现资金问题而导致连续停工超过10天、或退场，除按照合同约定承担相应责任外，同意贵公司按已完合格工程量的70%向我公司结算支付工程款；对于不合格工程或部分不合格工程，我公司放弃向贵公司工程款支付请求，并且无条件清除已完不合格工程；我公司保证无条件退场，且退场费用我公司自行承担。

4、本保证所涉我公司变更名称、住所、章程、法定代表人、经营范围、企业性质，或合并、分立、被撤销或破产等均不影响本保证书效力，我公司仍将承担保证责任。

5、本保证书的任何修改或补充都须事先征得贵公司的书面同意。

6、贵公司给予我公司的任何融通、宽限，或者合同及其附件的任何修改补充，都不影响我公司在本保证书项下的义务。

7、本保证书中所言合同包括合同协议书、合同文件、图纸、技术规范等。

8、本工程履约承诺保证书自我公司签署（盖章）之日生效。

工商行政管理局： 申请人郑重承诺：

1、已熟知与申请事项有关的《中华人民共和国民法通则》 、 《中华人民共和国公司法》 、中华人民共和国关于公司的法律法 规，明确并愿承担相应的责任和义务。

2、遵循《中华人民共和国民法通则》的诚实信用原则，保 证所填报的内容和提交的证件、 文件是真实的、 有效的、 合法的， 如有虚假愿承担由此引起的一切法律责任。 申请人保证

履行以上承诺。 本承诺保证书自签订之日起具有法律效力。 （注：以上所称"申请人"包括申请企业、全体股东、申请 企业法定代表人、承办人或委托代理人） 申请企业名称 法定代表人签字 承办人或委托代理人签字 全体股东（盖章、签名） ：

本单位 （单位名称）为进一步加强自身的消防安全管理工作，更好地遵守国家及北京市的相关消防法律、法规、规章和技术标准，在十七大消防安全保卫期间，做好单位内部消防安全工作，特郑重做出如下承诺：

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Uniaxial stress–strain relationship of concrete confined by various shaped steel tubesK.A.S. Susantha, Hanbin Ge, Tsutomu Usami *Department of Civil Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, JapanReceived 31 May 2000; received in revised form 19 December 2000; accepted 14 February 2001AbstractA method is presented to predict the complete stress–strain curve of concrete subjected to triaxial compressive stresses caused by axial load plus lateral pressure due to the confinement action in circular, box and octagonal shaped concrete-filled steel tubes. Available empirical formulas are adopted to determine the lateral pressure exerted on concrete in circular concrete-filled steel columns. To evaluate the lateral pressure exerted on the concrete in box and octagonal shaped columns, FEM analysis is adopted with the help of a concrete–steel interaction model. Subsequently, an extensive parametric study is conducted to propose an empiricalequation for the maximum average lateral pressure, which depends on the material and geometric properties of the columns. Lateral pressure so calculated is correlated to confined concrete strength through a well known empirical formula. For determination of the post-peak stress–strain relation, available experimental results are used. Based on the test results, approximated expressions to predict the slope of the descending branch and the strain at sustained concrete strength are derived for the confined concrete in columns having each type of sectional shapes. The predicted concrete strength and post-peak behavior are found to exhibit goodagreement with the test results within the accepted limits. The proposed model is intended to be used in fiber analysis involving beam–column elements in order to establish an ultimate state prediction criterion for concrete-filled steel columns designed as earthquake resisting structures. •2001 Elsevier Science Ltd. All rights reserved.Keywords: Concrete-filled tubes; Confinement; Concrete strength; Ductility; Stress–strain relation; Fiber analysis1. IntroductionConcrete-filled steel tubes (CFT) are becoming increasingly popular in recent decades due to their excellent earthquake resisting characteristics such as high ductility and improved strength. As a result, numerous experimental investigations have been carried out in recent years to examine the overall performance of CFT columns [1–11]. Although the behavior of CFT columns has been extensively examined, the concrete core confinement is not yet well understood. Many of the previous research works have been mainly focused on investigating the performance of CFT columns with various limitations. The main variables subjected to such limitations were the concrete strength, plate width-to- thickness (or radius-to-thickness) ratios and shapes of the sections. Steel strength, column slenderness ratio and rate of loading were also additionally considered. It is understandable that examination of the effects of all the above factors on performances of CFTs in a wider range, exclusively on experimental manner, is difficult and costly. This can be overcome by following a suitable numerical theoretical approach which is capable of handling many experimentally unmanageable situations. At present, finite element analysis (FEM) is considered as the most powerful and accurate tool to simulate the actual behavior of structures. The accurate constitutive relationships for materials are essential for reliable results when such analysis procedures are involved. For example, CFT behavior may well be investigated through a suitable FEM analysis procedure, provided that appropriate steel and concrete material models are available. One of the simplest yet powerful techniques for the examination of CFTs is fiber analysis. In this procedure the cross section is discretized into many small regions where a uniaxial constitutive relationship of either concrete or steel is assigned. This type of analysis can be employed to predict the load–displacement relationships of CFT columns designed as earthquake resisting structures. The accuracy involved with the fiber analysis is found to be quite satisfactory with respect to the practical design purposes.At present, an accurate stress–strain relationship for steel, which is readily applicable in the fiber analysis, is currently available [12]. However, in the case of concrete, only a few models that are suited for such analysis can be found [3,8,9]. Among them, in Tomii and Sakino’s model [3], which is applicable to square shaped columns, the strength improvement due to confinement has been neglected. Tang et al. [8] developed a model for circular tubes by taking into account the effect of geometry and material properties on strength enhancement as well as the post-peak behavior. Watanabe et al. [9] conducted model tests to determine a stress–strain relationship for confined concrete and subsequently proposed a method to analyze the ultimate behavior of concrete-filled box columns considering local buckling of component plates and initial imperfections. Among the other recent investigations, the work done by Schneider [10] investigated the effect of steel tube shape and wall thickness on the ultimate strength of the composite columns. El-Tawil and Deierlein [11] reviewed and evaluated the concrete encased composite design provisions of the American Concrete Institute Code (ACI 318) [13], the AISC-LRFD Specifications [14] and the AISC Seismic Provisions [15], based on fiber section analyses considering the inelastic behavior of steel and concrete.In this study, an analytical approach based on the existing experimental results is attempted to determine a complete uniaxial stress–strain law for confined concrete in relatively thick-walled CFT columns. The primary objective of the proposed stress–strain model is its application in fiber analysis to investigate the inelastic behavior of CFT columns in compression or combined compression and bending. Such analyses are useful in establishing rational strength and ductility prediction procedures of seismic resisting structures. Three types of sectional shapes such as circular, box and octagonal are considered. A concrete–steel interaction model is employed to estimate the lateral pressure on concrete. Then, the maximum lateral pressure is correlated to the strength of confined concrete through an empirical formula. A method based on the results of fiber analysis using assumed concrete models is adopted to calibrate the post-peak behavior of the proposed model. Finally, the complete axial load–average axial strain curves obtained through the fiber analysis using the newly proposed material model are compared with the test results. It should be noted that a similar type of interaction model as used in this study has been adopted by Nishiyama et al. [16], which has been combined with a so called peak load condition line in order to determine the maximum lateral pressure on reinforced concrete columns.Meanwhile, previous researches [17,18] indicate that the stress–strain relationship of concrete under compressive load histories produces an envelope curve identical to the stress–strain curve obtained under monotonic loading. Therefore, in further studies, the proposed confined uniaxial stress–strain law can be extended to a cyclic stress–strain relationship of confined concrete by including a suitable unloading/reloading stress–strain rule.2. Theoretical background2.1. Characteristic points on confined concrete stress–strain curveReferring to Fig. 1（General stress–strain curves for confined and unconfined concrete.）, the following characteristic points have been identified to define a complete stress–strain curve when concrete is confined by surrounding steel tubes. The notation in the figure is as follows: f ’c is the strength of unconfined concrete; f ’cc is the strength of confined concrete; εc is the strain at the peak of unconfined concrete; εcc is the strain at the peak of confined concrete; εu is the ultimate strain of unconfined concrete; fu is the ultimate strength of unconfined concrete; εcu is the ultimate strain of confined concrete; and αf ’cc is the residual strength of confined concrete at very high strain levels. The expression for the complete stress–strain curve is defined as suggested by Popovics [19], which was later modified by Mander et al. [20] and given by where fc and ε denote the longitudinal compressive stress and strain, respectively; Ec stands for the tangent modulus of elasticity of concrete. It should be noted that Eq. (1) has been defined even for the post-peak region, in this study, it is utilized only up to the peak point. The post-peak behavior is treated separately by assuming a linearly varied stress–strain relation as will be discussed in Section 4. 【1-4 Fig. 1】2.2. Confinement action in circular CFT columnsIn short CFT columns with relatively thick-walled sections designed for seismic purposes, failure is mainly caused due to concrete crushing. The mode of failure is governed by the individual behavior of each component. The behavior of concrete in CFT columns under monotonically increasing axial load can be explained in terms of concrete–steel interaction. The confinement effect does not exist at the early stage of loading owing to the fact that the Poisson ratio of concrete is lower than that of steel at the initial loading stage. At this level of loading, the circumferential steel hoop stresses are in compression and the concrete is under lateral tension provided that no separation between concrete and steel occurs (i.e., the bond between two materials does not break). However, as the axial load increases, the lateral expansion of concrete gradually becomes greater than the steel due to the change of the Poisson ratio of concrete, and therefore a radial pressure develops at the concrete– steel interface. At this stage, confinement of the concrete core is achieved and the steel is in hoop tension.Load transferring from the steel tube to the concrete occurs at this stage. It is observed that the load at this stage is higher than the sum of loads that can be achieved by steel and concrete acting independently.In the triaxial stress state the uniaxial compressive concrete strength can be given by 【5】 where frp is the maximum radial pressure on concrete and m is an empirical coefficient. In the past a lot of extensive experimental studies have been carried out to determine a value for coefficient m and it is found that for normal strength concrete, m is in the range of 4–6 [21]. In this study m is assumed to be 4.0. The radial pressure, fr, can be expressed by the relationship given in Eq. (6), which is easily derived by considering the equilibrium of horizontal forces on a circular section: 【6】Here, fsr, t and D denote the circumference stress in steel, the thickness and the outer diameter of the tube, respectively.3. Evaluation of confinement in various shaped CFT columns3.1. Circular sectionDetermination of the confinement level in circular tubes is found in the method proposed by Tang et al. [8]. In this method, the change of the Poisson ratio of concrete and steel with column loading is investigated. An empirical factor, β, is introduced for this purpose and subsequently the lateral pressure at the peak load is given by 【7】 Factor β is defined as 【8】 where νe and νs are the Poisson ratios of a steel tube with and without filled-in concrete, respectively. Here, νs is taken as equal to 0.50 at the maximum strength point, and νe is given by the following expressions: 【9 10】 Here, t, D and f ’c are the same as previously defined and fy stands for the yield stress of steel. The above equation is applicable for (f ’c/fy) ranging from 0.04 to 0.20 where most of the practically feasible columns are found within. A detailed description of the method can be found in Tang et al. [8]. It is clear that frp given by Eq. (7) depends on both the material properties and the geometry of the column. Subsequently, frp calculated from Eq. (7) is substituted into Eq. (5) to determine the confined concrete strength, f ’cc.摘要部分的翻译：各种断面形状钢管混凝土的单轴应力应变关系K.A.S. Susantha ， Hanbin Ge, Tsutomu Usami*土木工程学院，名古屋大学, Chikusa-ku ，名古屋 464-8603, 日本收讫于2000年5月31日 ; 正式校定于2000年12月19日; 被认可于2001年2月14日¬¬摘要一种预测受三轴压应力混凝土的完全应力-应变曲线的方法被提出，这种三轴压应力是由环形、箱形和八角形的钢管混凝土中的限制作用导致的轴向荷载加测向压力所产生的。有效的经验公式被用来确定施加于环形钢管混凝土柱内混凝土的侧向压力。FEM（有限元）分析法和混凝土-钢箍交互作用模型已被用来估计施加于箱形和八角形柱的混凝土侧向压力。接着，进行了广泛的参数研究，旨在提出一个经验公式，确定不同的筒材料和结构特性下的最大平均侧向压力。如此计算出的侧向压力通过一个著名经验公式确定出侧向受限混凝土强度。对于高峰之后的应力-应变关系的确定，使用了有效的试验结果。基于这些测试结果，和近似表达式来推算下降段的斜度和各种断面形状的筒内侧向受限混凝土在确认的混凝土强度下的应变。推算出的混凝土强度和后峰值性能在允许的界限内与测试结果吻合得非常好。所提出的模型可用于包括梁柱构件在内的纤维分析，以确定抗震结构设计中混凝土填充钢柱筒的极限状态的推算标准。 •版权所有2001 Elsevier科学技术有限公司。关键词: 钢管混凝土；限制；混凝土强度；延性；应力应变关系；纤维分析这是当年毕业时我的翻译，因为原文有图表等原文也超过10000字，没法在这里发，如需要原文（pdf版及word版）及全部翻译（5000字，中文），请留下邮箱。