This paper has evaluated the bending performance of a novel prefabricated MVFT steel-concrete composite girder. 9 meters pilot MVFT girder was analyzed by validated finite element model. In the pilot test, the height of web, the length of grouted concrete in the girder and net spacing between webs were parametrically modeled to discuss their effect to the bending strength. An ultimate bending strength formula has been obtained, which was based on the regression of parametric results. In the meantime, the two Machine Learning (ML) models, BP neural network and Least Squares Support Vector Machine, have been also implemented to train and then predict the ultimate strength of MVFT girder. Three factors were selected as input in ML models: the distance between steel girder's Tensile Centroid(TC) and slab's Compressive Centroid(CC), the distance between steel girder's TC and its CC, the compressive area of steel girder. After the completion of the ML training, the ultimate strength predictions of 30 meters MVFT girder by BP model and the formula have been compared, which agrees well with each other and validates their accuracy.

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Due to the demands of booming Chinese cities and the increase in urban residents, the safety of aqueduct water transportation structures is noteworthy. A lot of old aqueducts were built in the 1990s and even earlier in the last century and may become vulnerable to potential earthquakes. This paper deals with an evaluation of an aqueduct’s seismic vulnerability accounting for leakage risk. Based on the Hua Shigou aqueduct in Ningxia, a probabilistic investigation was carried out to obtain the seismic fragility using Latin hypercube sampling. In the numerical study, the superstructure and substructure of the aqueduct were modeled as beam elements, and the lumped mass method was adopted to simulate the fluid–structure interaction. The rubber water stop’s mechanical performance was studied, and its damage states were proposed. Parametric numerical models were then subjected to a set of ground motions according to incremental dynamic analysis (IDA), which contained probabilistic parameters such as water, concrete strength, and bearing performance degradation. Both the system and component levels of the old aqueduct’s seismic fragility curves were obtained. It was found that the probability of the water stop’s leakage risk is significantly elevated with the increase in ground motion.

<p>To investigate the structural performance and economic applicability of multi-span extradosed cable-stayed bridge, a comparative scheme of composite beam with corrugated steel web was designed based on the Wangjia River Bridge, which was an extradosed cable-stayed bridge with prestressed concrete girder built in Shaanxi. Spatial finite element models of the whole bridge were established by CSIBridge for extradosed cable-stayed bridge with two different sections of girder. Considering the influence of p-Δ effect, the vertical and horizontal deformation and the governing sections of the two forms were analyzed and compared. The material consumption of steel, concrete and steel strand of the extradosed cable-stayed bridge with corrugated steel web was calculated. The material consumption of the two schemes was compared. The differences in structural performance and economic cost for the two structures were explored. It’s expected to provide a reference for the tender design of multi-span extradosed cable-stayed bridges with similar span length.</p>