Study on bearing capacity degradation model for corroded steel fiber reinforced concrete segments on tension side
Feng Kun1 Geng Junyang1,4 Yang Renjie1 Xiao Mingqing2,3 Gong Yanfeng2,3 Xie Jun2 Gou Chao4
1. Key Laboratory of Transportation Tunnel Engineering of the Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China;
2. China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430071, China;
3. National & Local Joint Engineering Research Center of Underwater Tunnel Technology, Wuhan 430071, China;
4. CCCC First Highway Consultants Co., Ltd., Xi’an 710075, China
Abstract：In recent years, more and more steel fiber reinforced concrete(SFRC) segments are used in new shield tunnel and pipeline engineering. Meanwhile, in the corrosive environment, many segments face the problems of reinforcement corrosion. Under such circumstance, it is necessary to propose a calculation methods for residual bearing capacity of corroded SFRC segments. In this paper, a degradation model of corroded SFRC segments on tensile side is proposed according to the environment and stress characteristics of shield tunnel segments in service period. The calculation theory of bearing capacity of reinforced concrete structures is deduced and the corresponding solution steps are given. The bearing capacity curves of corroded tensile side SFRC segments with different corrosion level and different steel fiber content are analyzed. The analysis results by the proposed model are compared with the results of the synchronous accelerated corrosion of SFRC segments under compressive and bending loads to verify the applicability and reliability of the model. The main conclusions are as follows:① With the increase of steel fiber content, the cube compressive strength of concrete first increases and then decreases;② The maximum ultimate bending moment of eccentrically compressed segment decreases with the corrosion level of main reinforcement, but increases with the steel fiber content, but the increase amplitude decreases gradually; The maximum ultimate axial force is not affected by the corrosion level ofmain reinforcement, but increases first and then decreases with the steel fiber content. ③ The influence of corrosion ratio of main bars and steel fiber content on large eccentric compression members is greater than that on small eccentric compression members. The balanced eccentricity decreases with the corrosion level of main reinforcement and increases with the steel fiber content.
