现行规范钢筋混凝土偏压柱正截面承载力计算

依据《混凝土结构设计规范》(GB50010-2002)和《混凝土结构设计规范》(GB50010-2010)给出的钢筋混凝土偏心受压构件正截面承载力计算规定,结合本人教学中的体会,对计算中给出的二阶效应规定、控制截面弯矩计算、以及需要注意的事项进行了说明,并结合矩形截面偏心受压构件对称配筋设计实例,灵活运用知识点解决问题...     

钢筋混凝土环形截面受弯构件正截面强度计算

在平截面假定的前提下,推导了钢筋混凝土环形截面受弯构件正截面非均匀配筋的计算公式,并且应用MathCAD数学工具软件对某一环形截面均匀及非均匀配筋方式分别进行了不同弯矩作用下的配筋计算.计算结果分析表明,<混凝土结构设计规范>(下简称<规范>)简单套用偏心受压构件的计算公式是不妥的;所推导的新计算公式,补充完善了<规范>中环形截面正截面受弯构件强度计算的内容.     

“计算系数法”在混凝土结构设计中的应用

在混凝土结构设计中,受弯构件和大偏心受压构件的正截面承载力计算是设计计算的重点,受弯构件根据截面形式分为单筋矩形截面、双筋矩形截面、T形截面.“计算系数法”可以将以上构件的截面设计有机地结合起来.本文讨论了“计算系数法”在钢筋混凝土基本构件设计中的统一应用,方便以后学习、设计需要.     

关于“矩形截面偏心受压构件轴力——弯矩相关曲线分析”的探讨

在分析和总结了各种情况下钢筋混凝土矩形截面的偏心受压构件承载力N-M的相关曲线基础上,找出了给定截面尺寸、配筋和材料强度的偏压构件达到承载能力极限状态时所承担的数种Mu、Nu组合变化关系,并得出了当同一截面承受多种N、M内力组合时其最不利内力组合方式的确定方法及偏压构件在截面设计时设计图表的绘制,为设计计算提供了依据,同时也简化了计算。     

钢筋混凝土圆形截面受弯构件正截面强度计算方法

探讨了钢筋混凝土圆形截面受弯构件正截面非均匀配筋的计算方法,推导了有关计算公式,并应用MathCAD软件进行了计算.与现行<混凝土结构设计规范>公式计算结果进行对比分析,该计算方法具有明显的经济效益.     

混凝土梁正截面承载力—C值计算法

本通过极值分析，找出了混凝土受弯构件正截面设计参数－Ｃ，用－Ｃ值法设计，不仅能容量的完成某此特定条件下的设计，还实现了矩形与Ｔ形截面设计格式的统一，从而使受弯构件正截面设计思路和方法变得便捷。     

钢筋混凝土受弯构件正截面承载力计算的优化与简捷算法

对钢筋混凝土受弯构件截面提出一种优化设计和截面承载力的简捷计算方法，这种方法可大大加快截面设计速度。利用受弯构件计算公式的高速收敛性，将迭代法应用于受弯构件正截面承载力计算设计申，不需要查表或解方程，即可快速确定截面中性轴高度，计算出配筋。该法适用于各种截面型式，具有满足工程要求的精度。     

Visual Basic程序设计在桥梁结构计算中的运用——圆形截面偏心受压构件强度验算程序

通过圆形截面偏心受压构件强度验算程序设计实例,简要介绍了VisualBasic程序设计在桥梁结构计算中的运用,指出了其对实际工程利用的优势     

双筋矩形截面梁受压钢筋不屈服时的截面设计探讨与教学

双筋矩形截面梁正截面受弯承载力计算是混凝土结构课程的重要教学内容。当学生进行双筋矩形截面梁正截面受弯承载力计算时,受压钢筋达不到屈服强度是设计中会遇到的情况。如何在此情况下进行结构设计,是学生学习这部分内容的一个难题。本文通过算例分析,将受压钢筋达不到屈服强度时如何进行截面计算的两种方法进行对比,给出了各个方法的控制条件,在此基础上,对如何进行这部分教学内容进行探讨,旨在提高教学质量并锻炼学生思考、解决工程问题的能力。     

FRP加固RC圆柱正截面受弯承载力计算（英文）

运用数值计算方法对FRP加固钢筋混凝土（RC）圆柱截面特性进行计算,发现截面破坏时受压区高度主要受轴压比、FRP约束强度比和纵筋配筋特征值3个主要参数影响.根据数值计算的结果进行回归,提出了受压区对应圆心角θ的计算方法.数值计算结果显示,横向约束导致的混凝土应力提高以及纵筋屈服后的强化效应使RC柱破坏时截面受弯承载力远大于规范规定值.根据理论分析和36个大比例试件实测结果提出截面破坏时受弯承载力计算方法,计算结果与试验结果吻合很好.最后,对一个典型柱变形能力进行参数分析,研究轴压比,纵筋配筋特征值和FRP约束强度比对正截面变弯承载力的影响.结果显示FRP加固圆柱破坏时受弯承载力可以比规范规定的未加固柱受弯承载力提高50%左右.     

Unified expression for failure of reinforced concrete members in bridge

INTRODUCTION Reinforced concrete elements with box section are commonly used in horizontal subsystems and in vertical support of bridge structures. The horizontal structural members normally have box section and top flange. The vertical supports of the bridge usually have a box section also. To simplify the deduction of such structural member under combined forces, the box sections without top flange are discussed here. Fig.1 shows the typical section types of reinforced concrete members.…     

钢筋砼L-形截面双向拉弯构件正截面承载力的研究

对钢筋砼 L-形截面双向拉弯构件的正截面承载力进行了研究 ,还对三根钢筋砼 L-形截面双向拉弯构件进行了试验研究 .编制了计算机程序 ,可用于各种类型截面的计算 ;并用此程序对 L-形截面在双向拉弯作用下的 N- M相关曲线、等轴力下的 Mx- My相关曲线进行了计算分析 ,理论计算结果与试验结果吻合较好     

宽肢T形混凝土异型柱的有限元分析

按不同肢厚比设计了3组计算模型,应用ADINA有限元软件分析宽肢T形截面柱在单调荷载作用下的非线性特性,分析了轴压比、水平力作用方向对其承载能力的影响,并通过对柱底部钢筋与混凝土单元的应力、应变随荷载增加而变化的情况的分析,验证了宽肢异形柱对平截面假定的适用性。     

Ultimate Bearing Capacity of Hollow Spherical Joints Welded with Circular Pipes under Eccentric Loads

The National Swimming Center built for the 2008Beijing Olympic Games applies the polyhedron spatialframe structure, which is based on the foam physicstheory[1]. Its simple geometry is a square box of 170m×170 m×29 m. It can hold 17 000 people, theroof o…     

Bearing capacity of composite columns reinforced by concrete filled steel tube

In this study, nine simplified short composite columns consisting of core CFST (concrete filled steel tube) of different diameters and outer reinforced concrete were constructed to study their compressive performance under axial or eccentric compression. The failure mode is characterized by the crush of the outer concrete. The bearing capacity increases at first and then decreases with further increase of the position coefficient. It can be concluded that position coefficient is an important structural parameter that has considerable influences on the ultimate bearing capacity of the composite columns. The outer concrete, steel tubes and longitudinal reinforcement are found to work in a cooperative manner under axial or eccentric compression when the position coefficient is about 0.5. An improved bearing capacity algorithm that takes the position coefficient into account has been proposed based on the experimental and simulation results and current technical specification in China. It has been proven to be precise and safe.     

Mechanical Behavior of Rectangular Steel-Reinforced ECC/Concrete Composite Column under Eccentric Compression

In order to improve the seismic performance, deformation ability and ultimate load-carrying capacity of columns with rectangular cross section, engineered cementitious composite(ECC) is introduced to partially substitute concrete in the edge zone of reinforced concrete columns and form reinforced ECC/concrete composite columns.Firstly, based on the assumption of plane remaining plane and the simplified constitutive models, the calculation method of the load-carrying capacity of reinforced ECC/concrete columns is proposed. The stress and strain distributions and crack propagation of the composite columns in different states of eccentric compressive loading are analyzed. Then, nonlinear finite element analysis is conducted to study the mechanical performance of reinforced ECC/concrete composite columns with rectangular cross section. It is found that the simulation results are in good agreement with the theoretical results, indicating that the proposed method for calculating the load-carrying capacity of concrete/ECC composite columns is valid. Finally, based on the proposed method, the effects of ECC thickness, compressive strength of concrete and longitudinal reinforcement ratio on the mechanical performance of reinforced ECC/ concrete composite columns are analyzed. Calculation results indicate that increasing the thickness of ECC layer or longitudinal reinforcement ratio can effectively increase the ultimate load-carrying capacity of the composite column with both small and large eccentricity, but increasing the strength of concrete can only increase the ultimate loadcarrying capacity of the composite column with small eccentricity.     

倒T型钢混凝土组合梁正截面抗弯承载力计算分析

由一般的非对称性工字型钢混凝土组合梁,采用变形协调模型推导总结不同情况下的型钢混凝土组合梁正截面抗弯承栽力计算公式,进而得到倒T型钢混凝土组合梁的正截面承载力。通过算例,采用推导的理论公式及ANSYS软件对等截面、等含钢量的两类组合梁的极限承栽力进行分析计算,表明倒T型钢混凝土组合梁正截面受力较工字型钢混凝土组合梁好及采用的理论公式是正确可行的。     

Experimental study of lightweight aggregate concrete under multiaxial stresses

Lightweight aggregate concrete cube specimens (100 mm×100 mm×100 mm) and plate specimens (100 mm×100 mm×50 mm) were tested under biaxial compression-compression (CC) and compression-tension (CT) load combinations. For comparison, normal concrete plate specimens (100 mm×100 mm×50 mm) were tested under the same load combinations. Based on the test results, a two-level strength criterion of lightweight aggregate concrete in both octahedral stress coordinate and principal stress coordinate was suggested. The lightweight aggregate concrete cube specimens (100 mm×100 mm×100 mm) were then tested under triaxial compression-compression-compression (CCC) load combination with corresponding tests on normal concrete cube specimens (100 mm×100 mm×100 mm). The effect of intermediate principal stress on triaxial compressive strength is further examined. A "plastic flow plateau" area was apparent in principal compressive stress-strain relationships of lightweight aggregate concrete but not in normal concrete. A quadratic formula was suggested for the expression of strength criterion under triaxial compression.     

Analysis and behaviour of FRP-confined short concrete columns subjected to eccentric loading

Fibre-reinforced polymer （FRP） composites were widely utilized in civil engineering structures as the retrofit of reinforced concrete （RC） columns. To design FRP jackets safely and economically, the behaviour of such columns should be predicted first. This paper is concerned with the analysis and behaviour of FRP-confined RC circular and rectangular short columns subjected to eccentric loading. A simple design-oriented stress-strain model for FRP-confined concrete in a section analysis was first proposed. The accuracy was then proved by two test data. Following that, a parametric study including amount of FRP confinement, FRP strain capacity, unconfined concrete strength and shape of column section is provided. Some conclusions were obtained at the end of the paper. The work here will provide a comprehensive understanding of the behaviour of FRP-confined concrete columns. The simplicity of the model also enables a simple equivalent stress block to be developed for direct use in practical design.