《混凝土结构设计原理》双语 (4).ppt

Chapter 4 Analysis Methods of Reinforced Concrete Members 4.1 Design and analysis 4.2 Analysis methods for R.C. structures 对承受各种内力（轴力、弯矩、剪力、扭矩）的一维构件和二维、三维结构，应力分析后都可以找到主应力方向，在主应力方向无非是压力或拉力。 沿主拉力方向配筋当然最为有效，在主压力方向加设钢筋也有增强作用。 钢筋混凝土轴心受力构件是最简单，也是最基本的受力状态，掌握其受力性能的一般规律，是了解其它构件性能的基础。从中可以可到进行钢筋混凝土构件截面分析的一般方法。 4.2.1 Basic functions in structural analysis 4.2.2 Analysis of axially loaded short column (compression) Reinforcement ratio Basic functions Compatibility: Equilibrium condition 4.2.2.1 Loading process εyεp (HPB235) Stage 1 Stage 2 Stage 3 Stage 4 4.2.2.2 Loading process εyεp (fy=600MPa) 4.2.3 Analysis of axially loaded short column (tension) Basic functions The compatibility condition and equilibrium condition are same as those in compressive The constitutive law of steel is same as that in compression The constitutive law of concrete in tension is different 4.3 Summary of properties of R.C. structure Nonlinear process with multi-stages Elastic→plastic→cracking of concrete→yield of steel→ultimate load→ failure Redistribution of stress between concrete and steel Steel and concrete do not reach their ultimate strength simultaneously, over lap is dangerous. In tension, cracking section , uncracking section Tension stiffening Plane cross section remain plane during loading (Bernoulli assumption) Compression √ Tension ----average over a distance * ? Analysis Design Known Sectional dimensions Reinforcement Strength of material Inner force Loads Properties of materials Solve Load carrying capacity Deformation Crack width Structures which can satisfy predicted functions Characteristics Certainty problem Uncertainty Comprehensive Load Deformation Stress Strain Equilibrium condition Constitutive law Compatibility 下面通过轴心受力构件来表示以上材料力学基本方程在钢筋混凝土截面受力分析中的应用方法。并从中得到受力分析的基本规律（注：实际工程中严格意义的轴心受拉、受压是不存在的） In practical design, Ac is usually taken as the normal concrete area, without deduction (扣除） for t