上海交通大学：《钢筋混凝土基本原理》课程教学资源（PPT课件）Chapter 4 Analysis Methods of Reinforced Concrete Members

Concept ·Reinforcement ratio A A In practical design,Ac is usually taken as the normal concrete area,without deduction (for the area of longitudinal reinforcement(纵向钢筋)

• Reinforcement ratio c s A A   In practical design, Ac is usually taken as the normal concrete area, without deduction (扣除） for the area of longitudinal reinforcement（纵向钢筋）. Concept

Basic functions ·Compatibility: Es=8c Constitutive law: Constitutive law for steel bar When s,≤8y( s=EEs When &3 o=fy=const f E。E0Em Constitutive law for concrete Oc=f(8c)=AE08c A-k Plastic coefficient Ee

Basic functions • Compatibility: s c    • Constitutive law: Constitutive law for steel bar When s y    s Es s    When s y    f const  s  y  Constitutive law for concrete c c E c  f   0  ( )  E0 Ec   Plastic coefficient

When 8e=0 λ=1 E c=p 入 Eo a EcrEp 元↓ Concept Stress ratio (under the condition of compatibility) o-6,E=6,E2=E/E=n 0.6eE。 eE。 由于混凝土的软化 (入↓)钢筋承受的压 力占总额的比例随总压 Where n= Es modular ratio (const. Eo 力的上升而上升

When  0 c   1 c p    E a Ep 1 0    c p              E E n E E E E s c s s c c s s c s     0 0 Stress ratio (under the condition of compatibility) Where E0 E n s  modular ratio (const.) 由于混凝土的软化 （λ↓）钢筋承受的压 力占总额的比例随总压 力的上升而上升。 Concept

Equilibrium condition N=a,A+a,A,=0,A1+7p)=a,A 4=A+月p)=A+贸 Concept n As is transform section or equivalent section for reinforcement(折算为混凝土截面积)

• Equilibrium condition 0 (1 ) A n N c Ac s As c Ac   c            n A A n A  Ac   c  s (1 ) 0  n As is transform section or equivalent section for reinforcement（折算为混凝土截面积） Concept