Papers by Keyword: Durability Design

Abstract: In this paper, based on accelerated testing indoors, under the action of bending tensile stress on a marine high-performance concrete chloride ion diffusion coefficient, the results show that: Subjected to bend under the action of tensile stress and do not withstand the test piece chloride diffusion coefficient increases with increasing stress levels, different tensile stress and does not bear the stress of the concrete chloride ion diffusion coefficient ratio (D_η/D₀) exponential relationship with the stress level (η). In addition, addition, for a domestic Bridge, preliminary design to determine typical parameters of components and their environment is proposed to consider the durability of concrete structure load control index calculation method, to establish a "design life - chloride ion diffusion coefficient controlled targets" the correspondence between, for similar projects designed to provide a reference durability.

Abstract: For concrete structure durability increasingly highlight of problem, focus description has chlorine ion on concrete structure of erosion mechanism, and invaded model and effects factors, derivation out integrated consider concrete of chlorine ion combines capacity, and chlorine ion proliferation coefficient of time dependence, and concrete structure micro-defects effects and the mixed coagulation s performance of practical proliferation equation, established has for forecast concrete using life of chlorine ion proliferation theory model, made intends built structure in chlorine ion environment Xia durability design thought and design method, Perfected design theory of durability of concrete and carbonation model design based on Carbonation depth of concrete during the period, compared with the concrete cover thickness, for engineering design and revision of the specification reference.

Abstract: The fundamental approach for solving the durability deficiency is to perform the durability design for planned concrete bridges and the durability maintenance for existing concrete bridges. Most of the existing durability design and maintenance methods, however, are qualitative and contain many subjective factors, which cannot solve the problems such as whether the structure is safe or not throughout the service life. The critical problems, such as the design service life, the environmental parameters, the material degradation process, as well as the lifetime performance assessment method, are found out based on deep insight into the existing concrete bridge durability design and maintenance methods. Finally, the schematics of concrete bridge durability design and maintenance methods that can quantitatively evaluate the degradation process of concrete bridges are proposed and the further research direction is determined.

Abstract: This paper introduces durability design method of tunnel lining structures based on approximate probability. According to the method, the corresponding application program, named tunnel lining structures durability design program (TLSDDP), has been developed, which can be used in the similar tunnel lining structures durability design in the future. TLSDDP was applied in Shanghai Yangtze River Tunnel lining structures durability design and the tunnel durability design limit state equation was obtained.

Abstract: When the RC structure degraded in sea environment, chloride ion is one of the most important factors of degradation. Therefore, the purpose of this analytical study is measuring diffusion coefficient of patching repair material and the structure which repaired with patching repair material by RCPT. Also with this experimental result, Finite Element Method (FEM) is used for determining service year of building and concentration of chloride ion in the structure material. As the result of RCPT, diffusion coefficient of patching repair material is 0.44×10-8cm2/sec, which is 18.7% of concrete (3.18×10-8cm2/sec). Meanwhile, as the result of FEM, patching repair material is effective for prevent chloride ion. When service year of normal concrete structure is 16years, on the other hand, the structure recovered 10mm of patching repair material will take 49 years to its service year. Furthermore, the result derived from equation given from JSCE predicts service year of the structure is little bit less than FEM.

Abstract: To develop a durability design procedure based on lifetime safety factor method, different dose-response functions based on both ISO standards and the literature are presented for the prediction of the thickness loss due to atmospheric corrosion in metal structures. Finally, serviceability and ultimate limit states are defined for the durability design against corrosion.