JPKic 结构热计原黑 Conversion section moment of inertia of crack section x+a4,-x 3 Depth of compression zone x Rectangular cross section For bending,cracking the neutral axis of the section throug the conversion of its cross-shaped spindles that| Soc Sor r get 如2=w4a,-一寸 2bho X二 1+ 一1 b
Conversionsectionmoment of inertia of crack section ( ) 2 0 3 3 1 I bx A h x cr = + Es s − Depth of compression zone x： S0c = S0t that Rectangular cross section：For bending, cracking the neutral axis of the section through the conversion of its cross-shaped spindles ，get bx A (h x) = E s s 0 − 2 2 1 = + −1 2 1 0 E s s E s s A bh b A x
JPKIC 结构设计原理 Tfeprnisipledistnctiredesign T-shaped cross-section ①x≤h好 By the width of the rectangular cross sectionsection Conversion section of crackgeometry ②x>h Show that the neutral axis in the T-shaped cross-section of the ribs x=AP+B-A Where A= &4+6-,B-2a,4+6- b b Transformed section moment of inertia axis of one of the 11= ,术☐6-b成t-九】+aeAa- 3 3
T-shaped cross-section ： hf ① x By the width of the rectangular cross section section Conversion section of crackgeometry ② hf x Show that the neutral axis in the T-shaped cross-section of the ribs x = A + B − A 2 Where ： ( ) ( ) b A h b b h B b A b b h A E s s f f E s s f f 2 2 0 + − = + − = ， Transformed section moment of inertia axis of one of the : cr I ( )( ) ( ) 2 0 3 ' 3 ' ' 0 1 3 3 A h x b x b b x h I E s s f f f + − − − = − f b f b f b f b f b f b f b ' f h
JPKic 箱构计原黑 $9.2.4 Conversion of the whole cross-sectioncross-section Definition Concrete all-sectional area and conversion of steel areas made up of sections. Geometric characteristics Ao =bh+(br-b)h'+(Es-1)As Ibh2(bby+(cgs_1)4.ho x= Ao
§9.2.4 Conversion of the whole cross-section cross-section ⚫ Definition：Concrete all-sectional area and conversion of steel areas made up of sections. ⚫ Geometric characteristics： A bh bf b hf E s As ( ) ( 1) 0 = + − + − 0 0 2 2 ( ) ( _1) 2 1 2 1 A bh b b h A h x f f + E s s + − =
JPKIC 结构设计原理 hepniiplestncturedesgn =吉放城号-点-4八 +(,-b(5-x)2+(a-1)A,(h。-x)
2 0 2 3 2 3 0 ) ( 1) ( ) 2 1 ( ) ( ( )( ) 12 1 ) 2 1 ( 12 1 b b h h x A h x I bh bh h x b b h f f f E s s f f + − − + − − = + − + −
JIPKIC 结构设计原理 The principle of structure design $9.3 Stress check §9.3.1 Stress limit For reinforced concrete flexural member,of the rules of highway bridge construction stage stress calculation of request and internal force combination according to the possible construction loads and bending flexural stress should meet the following conditions: Edge of the concrete in compression zone Fiber stress: cc ≤0.80fk O Tensile reinforcement stress: o≤0.75f
§9.3 Stress check §9.3.1 Stress limit For reinforced concrete flexural member, of the rules of highway bridge construction stage stress calculation of request and internal force combination according to the possible construction loads and bending flexural stress should meet the following conditions: ⚫ Edge of the concrete in compression zone Fiber stress: ck t cc 0.80 f sk t si 0.75 f ⚫ Tensile reinforcement stress: