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This study presents a collaborative sensing approach that integrates the pre-embedded sensor method and the impact-echo technique to enhance the accuracy of grout filling quality assessment for precast concrete sleeve connections. The pre-embedded sensor method, which relies on vibration energy attenuation, enables continuous monitoring of the grout filling process; however, its accuracy is limited at low filling degrees, as vibration energy values remain constant at approximately 255 when the filling degree is below 70%. In contrast, the impact-echo technique, based on the principle of impact elastic wave propagation, demonstrates high accuracy in evaluating grout filling degrees across various levels, with reflected waveform amplitude increasing accordingly. This collaborative approach establishes a functional relationship between vibration energy values from the pre-embedded sensor method and grout filling degree, allowing for a comprehensive assessment of grout filling quality. In field demonstrations, the calculated grout filling degree values deviated by less than 5% from the set values. Practical guidelines for implementing the collaborative sensing approach are also provided. The method developed in this study offers a reliable solution for assessing grout filling quality in precast concrete sleeve connections, addressing the limitations of individual testing methods. [ABSTRACT FROM AUTHOR]

Currently, one of the challenging tasks for Chinese engineering community is to construct a water-way crossing of Qiongzhou Strait in the south of China. This project has also gained significant attention from researchers in academia. The study presented herein is centered on providing a feasible solution for ac-complishing the above mentioned task. Initially, different alternatives as the best location, judged on the basis of the environmental constraints, are studied. Then the comparison between various structural solutions such as suspension bridge, submarine tunnel and SFT is presented. Among these solutions, SFT appears to be a very suitable alternative for Qiongzhou Strait waterway crossing due to distinctive advantages, like shorter distance, lower cost, less impact on environment and navigation, etc. Based on the appropriate conception for cross sections, support systems, materials, joints and connection schemes, a numerical model is developed by means of the FEM software ANSYS/Fluent. It is then analyzed under the influence of different environmental loading conditions, varying the wave heights and lengths, current velocities and water depths, which are typical in Qiongzhou Strait. The numerical results reveal that the proposed SFT solution performs safely even under extreme weather conditions.