Columns under axial compression and biaxial bending . in the beginning of the paper , it summarized the history and the actuality of the nonlinear analysis of special - shaped columns and the capability of the sliding of reinforcement anchoring . on the basis of related papers , the full path of stress - strain relation of concrete and the sliding of longitudinal reinforcement anchoring are all considered 本论文主要内容是对钢筋混凝土异形截面双向压弯柱(包括l形、 t形、十字形柱)进行非线形全过程分析,首先综述了异形柱构件非线性分析以及粘结滑移性能研究的历史与现状,在有关文献基础上考虑了受拉纵筋和周围混凝土的粘结滑移和混凝土应力?应变关系曲线的下降段。
Based on the engineering requirement , much application technological research has done on the compression of frame beams , concrete stress , anchoring loss , hole friction loss and the measuring of the inverted arch . and some useful suggestion has been tendered to improve the calculating and design method and optimize the construction 结合工程需要，对框架梁的压缩、混凝土应力、锚固损失、孔道摩擦损失和反拱等的测试进行了实用技术研究，为改进计算设计方法和优化施工提出了有关建议。
All concrete structures are exposed to volume changes caused by hydration reactions in the early age . if the volume changes are restrained , stresses is generated which will cause cracking when it overcomes the tensile strength . as the mechanical properties of early age concrete vary with time , especially the creep degree depends on the time elapsed and the time at loading , to calculate the stress of concrete structure is a complex nonlinear problem . the finite element method ( fem ) can take account of the evolution of the stiffness properties , the development of thermal strain , creep , shrinkage and so on . in this paper , a general approach for numerically simulating this type of behaviour is presented firstly . then , how to solve this problem is introduced by the general finite element software ansys using the initial stress method . finally , a detailed description of an example calculation that demonstrates the potential of the numerical simulation strategy follows 早期混凝土由于水化反应都会产生体积变化.如果体积变形受到约束就会产生应力,一旦超过混凝土的抗拉强度就会产生裂缝.由于早期混凝土的力学性能是随时间变化的,特别是徐变,它不仅与加载时间有关而且同时随龄期而变化,因此计算早期混凝土结构应力是较为复杂的问题.有限单元法不仅可以考虑混凝土刚度的变化,而且可以考虑温度、徐变、收缩等因素.本文利用初应力法对通用有限元软件ansys进行了二次开发,通过工程实例计算了高层建筑地下室侧墙早期混凝土应力的变化过程,并提出了相应的抗裂措施
Early age cracking of concrete has re - emerged as an important issue all over the world in recent years . the stress , due to restrained volume change related to thermal deformation and shrinkage in the early age concrete , is the main driving force for the deleterious cracking in the construction stage . during the development of the stress , creep , a very important property of concrete , is always developing . creep contributes to 40 ? - 50 ? reduction of the elastically induced stress in the restrained specimen . ring test , a qualitative test , can provide information to assess the potential for cracking of different concrete . an overview of ring test developed in recent years and mechanism of uniaxial tensile creep test is described in this paper at first . then , an innovative test equipment based on ring test is outlined 近年来混凝土早期裂缝问题再次引起全球工程界的广泛关注.早期混凝土由于体积变形受到约束而产生的应力是导致混凝土开裂的主要因素.在混凝土应力发展的同时,混凝土徐变也在同时发生着变化.有研究表明,徐变能减少40 ? - 50 ?的早期应力.圆环试验是用于定性评价混凝土材料抗裂性能的试验方法之一.本文首先分析了圆环试验和单轴拉伸徐变试验的原理,创造性地将圆环试验用于测量早期混凝土的干缩徐变,并设计了试验方案
In this test , a special bolt - jack is used to exent of prestressing force to brace angles as the whole structure is under dead - load . in this state brace angles withstand partly load before twice - load and the stress and strain of concrete are decreased . in this way the aim of removal of load and strengthening can be reached 本试验中采用专用螺栓千斤顶在恒定荷载水平下对混凝土柱角钢撑杆施加预压应力，使外包角钢在二次受力前即分担部分荷载，使混凝土应力水平和应变水平降低，达到卸载与加固同步进行的目的。
The content of the paper is nonlinear analysis of complete response process for t , l - shaped and " + " shaped section r . c . columns under axial compression and biaxial bending . on the basis of related papers , the full path of stress - strain relation of concrete and the sliding of longitudinal reinforcement anchoring are all considered , simultaneously , the restriction effect for concrete by thickening of stirrups is also included 本论文主要内容是对钢筋混凝土异形截面双向压弯柱(包括l形、 t形、十字形柱)进行非线形全过程分析，在有关文献基础上考虑了受拉纵筋和周围混凝土的锚固滑移和混凝土应力?应变关系曲线的下降段，同时考虑到在箍筋加密区箍筋对混凝土的约束影响。
Based on this test , this paper discussed the bearing performance and influencing parameters of concrete confined with cfrp , and presents its new model of pressive strength 、 peak strain and stress - strain relationship according to existed the models of stress - strain relationship which are used to calculating concrete confined with fiber reinforced polymer ( frp ) 结合试验,本文对cfrp约束混凝土的受力性能及影响参数进行了分析,基于已有的frp ( fiberreinforcedpolymer )约束混凝土应力-应变关系模型,提出cfrp约束混凝土的抗压强度、峰值应变及应力-应变模型。
This thesis has made the contrast test of shrink and creep for plain concrete and concrete filled steel tubes on the basis of long term in - door test , obtains the principles of shrink - creep of concrete filled steel tube , simulates the test data , analyses and contrasts the coefficient of shrink and creep , thus offers reference for the calculation mode of creep , furthermore by introducing reasonable assuming at the same time , develops the calculation formula of equivalent elastic modulus at the same time , develops the calculation formula of equivalent elastic modulus , adopts common structure analyses procedure ansys to calculate the redistribution of section stress in the steel tube and concrete during operation 本文在长期的室内试验的基础上对素混凝土和钢管混凝土做了收缩和徐变的对比试验,得出钢管混凝土的收缩徐变规律,对试验数据进行了拟合,对钢管混凝土的收缩和徐变系数进行了分析和比较,从而为钢管混凝土的徐变计算模式提供参考,同时通过引入合理的假定,并结合由“龄期调整有效模量法”导出的混凝土徐变本构关系,推导出了钢管核心混凝土考虑徐变影响后的等效弹性模量计算公式,并以此为基础采用通用结构分析程序ansys对成桥后钢管和混凝土应力重分布进行了计算。
In this thesis , it is analyzed theoretically the steel bar layout pattern , the prestress loss , the concrete stress , and the discipline of the deformation and the fracture forming of structures of the partial prestress concrete frame beams , which is widely used in modern civil engineering 本文从理论上分析了现代建筑工程中广为采用的部分预应力混凝土框架梁的布筋方式、预应力损失、混凝土应力、结构变形和开裂规律；导出了具有一般意义的预应力锚固损失以及梁的长期挠曲变形计算公式。
4 . traditional theories for restrained stress of mass concrete does not agree with the construction method of long block without longitudinal joints , but now more and more dams are being constructed this way . by numerical simulating , this paper studies the temperature in and thermal stress developing process of column concrete blocks with different lengths ( 20m , 40m , 60m , 80m , 120m ) 针对常规的混凝土应力计算方法不支持长浇筑块的通仓浇筑方案，而通仓浇筑方法却在工程实际得到越来越多的应用(如二滩，最长浇筑块为60m ；溪洛渡，最长浇筑块为69m )的情况，通过数值仿真分析计算方法，在同等条件下计算了不同浇筑块长度( 20m 、 40m 、 60m 、 80m 、 120m )的温度过程与应力发展过程。
