Research On Shear Behavior Of Multiple-Keyed Dry Joint Of C40 SFR Concrete

As a result of rapid construction, the construction technology of prefabricated assembly has greatly shortened the construction period and reduces the needed workers for the project. It is favored in the expensive labor cost area in European and American countries, and so as in the developing countries in the future. At the same time, due to its rapid construction, its impact of the surrounding environment and traffic is at a relatively low level. It’s suitable for the modern busy urban environment. Due to it could be prefabricated in the factory, the section of the bridge’s quality can be guaranteed. At present, China is in a period of rapid development, with the progress of the society, the improvement of people’s living standard, the labor cost is also growing rapidly. Fast construction technology has a very broad application prospects. Due to its advantages of rapid speed and safety and the construction technology of precast concrete segmental bridegs will be more and more used in our country. However, the structural and mechanical behavior of joints between segments in China is lack of systematic research and design specifications. This has brought problems to the design. According to the research of "Research on key problems of Precast Segmental Concrete Bridges with Dry Joint" by Guangdong Provincial Department of education on the project of innovation and strengthening universities (2014 KTSCX060), this paper deeply studies the shear strength of the key based on previous studies. The main research includes the following aspects:(1) Construction of joint of Precast Concrete Segmental Beam BridgeJoint is the important part of precast concrete segmental bridge. The structural characteristics and application scope of different types of joints will be summarized. Dense key structure is adopted in the joint surfaces of precast concrete beam bridges in modern segment. By analyzing the structure and stress characteristics of the keys in different parts of the section, the design method of the keys will be summarized.(2) Experimental study on shear behavior of steel fiber reinforced concrete multi-keyed dry jointDue to the existence of the joints and the external prestressing, the precast concrete segmental bridges are different from the conventional monolithic prestressed bridges. Based on summarizing the domestic and foreign relevant experimental studies, steel fiber concrete is used in the experiment and shear capacity test of the precast segmental steel fiber reinforced concrete bridge is designed.The crack development and failure mode and the influence factors on shear strength of multi-keyed dry joint of the precast steel fiber reinforced concrete bridges is analyzed in this paper.(3) Different types of specimens are tested on the experimental parameters such as the normal stress, the type and quantity of the keys, and the type of the concrete. Crack development process and damage pattern of the keys were observed and recorded. The difference of shear resistance of specimens under three levels of normal stress conditions is compared. The difference of the shear capacity under different type of keys contact conditions is compared. Under the condition of ordinary concrete and steel fiber reinforced concrete, the difference of the shear capacity of the keys is compared. The test results are analyzed in detail from the above different parameters, and the applicability of AASHTO LRFD formula is investigated.