Comparative Analysis For Calculation Methods Of Shear Capacity And Prestress Losses Of Concrete Members In Chinese,American And European Code

Bridge plays an irreplaceable role in modern road traffic system. With the rapid development of science, technology, economy and culture, the bridge construction and design have developed rapidly in China, but compared with the developed countries there is still a big gap. Code for concrete bridge JTG D62-2004, AASHTO LRFD Bridge Design Specification 2012 and EN 2:Design of concrete structures.Part 2:Concrete bridges are selected, compared and studied based on the national basic project (973 project) "The fundamental research of extra long-span bridge safety design and evaluation" (2015CB057703) to understand the bridge design specifications of developed countries, promote the international competitiveness of bridge construction and perfect Chinese bridge design specifications. The detailed works listed as follows:(1) Shear capacity for reinforced concrete and prestressed concrete membersChinese Code, American Code and European Code are selected to analyze the methods for calculating shear strength of concrete members. Influence factors, critical section, maximum shear strength and minimum stirrup ratio were comparatively analyzed. Used a slab without transverse reinforcement and a tee beam with transverse reinforcement as examples, and calculated shear strength according to the three codes. Calculated results of shear capacity were compared with the experimental results. It is shown that the three codes choose different critical sections and models to calculate shear strength, and different factors are considered in the design equations. Calculated results of shear capacity based on the three codes are conservative compared with the experimental results. Minimum stirrup ratio in Chinese Code does not consider the influence of concrete strength, but the minimum stirrup ratio in American Code and European Code increase with the increasing concrete strength. Maximum shear strength in the three codes increases with concrete strength.(2)Prestress losses for prestressing concrete membersA comparative study was made for stressing limits of prestressing tendons, instantaneous losses, time-dependent losses and total loss of prestress in Chinese Code, American Code and European Code. Used a post-tensioning prestressed concrete tee beam as an example, and calculated prestress losses according to the three codes. It is concluded that all the three Codes use superposition method to calculate total loss of prestress, but types of prestress losses considered in each stage are different. Calculation methods for long-term prestress losses are very different.