Issue 37

Z. Hongping et alii, Frattura ed Integrità Strutturale, 37 (2016) 352-359; DOI: 10.3221/IGF-ESIS.37.46 355 Statistical Parameters of Resistance of Corroded Bending Element Bending element is the most common structural element in existing reinforced concrete structure. After years of research on corroded element, the calculation of bearing capacity of corroded bending element has been quite mature. Taking bending element of reinforced concrete as an example, resistance decrease rules of corroded bending element is analyzed in this section. According to relevant knowledge of concrete structure design, bending capacity of normal section of rectangular section of corroded element can be obtained from the following formulas. 1 ( ) 2 v x Y f lx b    (9) 1 se o v B f x f l   (10) where Y stands for bearing capacity of normal section of corroded reinforcement (kN · m), v f and 0 f stand for compressive strength of concrete axis and yielding strength of reinforcement (MPa); 1  stands for coefficient (the value is determined according to relevant regulations in Code for Design of Concrete Structures); l and b stand for the width of section and effective height of section (mm); se B refers to equivalent section area of tensile reinforcement (mm 2 ) which is calculated using formula (11). 1 n se sj sj sj i B K B     (11) where sj K refers to coordination coefficient of ith reinforcement (decrease of cohesive force is considered), sj B refers to section area of jth tensile reinforcement (mm 2 ), and sj  stands for reduction coefficient of yielding strength of jth reinforcement. ( ) ( ) ( ) 1 2 P C b r t t t            (12)   2 2 2 2 2 2 2 2 ( ) ( ) ( ) 1 ( ) ( ) 4 P c C l f b r v t t t b t t                             (13) 1 ( ) ( ) C l b f v t t        (14) where fv  and fv  stands for average value and variable coefficient of compressive strength of concrete axis, l  and l  refers to average value and variable coefficient of section width, b  and b  refer to average value and variable coefficient of effective height of section, and ( ) C t  and ( ) C t  refer to average value and variable coefficient of yielding tensile force of corroded reinforcement. Through analyzing parameters of mode, we can finally obtain relevant uncertainty statistical parameters of resistance of corroded bending element of reinforced concrete. A NALYSIS METHOD OF STRUCTURAL TIME-DEPENDENT RELIABILITY Basic Principle of Time Comprehensive Analysis method ime comprehensive analysis method means to take the whole service period of a structure as a reference time period during analysis of structural reliability and obtain resistance and load model considering the changes of structural resistance and loading during the time period. The whole service period is regarded as a reference time period, and statistical characteristics T