Static and Seismic Characteristics of Cable-Stayed Bridges with New Stay Systems

Abstract

<p>This paper presents static and seismic structural behaviours of cable-stayed bridges with two new cable systems: the overlapping stay system and the hybrid cable system. First, static analysis is carried out for four cable-stayed bridge models with three different patterns of live load consisting</p><p>/of the train and vehicle loads. The live load distributed in the mid-span gives larger deflection for all four models. The overlapping stay system and the hybrid cable system can significantly reduce the displacements of the girder and bending moment of the towers due to live loads. The deflection of the girder with the overlapping stay system due to the train loads decreases by 9.5% and the hybrid cable system decreases by 10% in comparison with the conventional cable system. The deflection of the new cable systems are within the allowable value specified for the Japanese bullet train, confirming that serviceability limit is satisfied. Second, seismic response of the four cable-stayed bridge models was investigated for the ultra-large seismic waves. The longitudinal displacement of the girder and the tower top and bending moment at the tower base was smallest for the overlapping stay system among the four bridge models, showing better seismic performance than the conventional cable-stayed bridge. In conclusion, the cable-stayed bridges with the overlapping stay system and that with the hybrid cable system provide better serviceability and better seismic performance as well, which validates the superiority of these structures.</p>

Serviceability Assessment Method of Stay Cables with Vibration Control Using First‐Passage Probability

“…This section describes the proposed serviceability assessment method for stay cables equipped with vibration control measures. Most modern developed countries have design specifications that define the serviceability failure of stay cables [1,[14][15][16]. For example, the Korean design code states that the maximum allowable deformation of a stay cable must be less than 1/1600 of the cable length at the middle of the cable under the external wind of mean speed less than 20 m/s for 10 minutes [14].…”

“…The US Department of Transportation classifies the vibration comfort level of bridge users into three levels: 'not allowable' when the cable vibration amplitude exceeds 2.0 D, 'recommended' when the cable vibration amplitude is near 1.0 D, and 'preferred' when the cable vibration amplitude is near 0.5 D, where D is the diameter of the stay cable [15]. In Japan, the serviceability of bridges with stay cables is analyzed on the basis of the criterion of the Japanese Railway Bridge Specifications, which defines allowable deflection as L/2000 at midspan of the bridge deck, where L is the span length in question [16]. In the Chinese Highway Cablestayed Bridge Design Specification, a serviceability failure is considered to have occurred on a cable-stayed bridge when the deflection at midspan of the bridge deck is over the allowable deflection of the bridge, defined as L/400, where L is the span length in question [1].…”

Automated Real-Time Assessment of Stay-Cable Serviceability Using Smart Sensors

“…The Korean government assigns the acceptable serviceability level of stay-cables based on the amplitude of vibration of the cable at mid-span, which is less than L/1600 under an average oncoming wind speed of less than 20 m/s for 10 min, where L is the length of the subject stay-cable [4]. Both the Japanese and Chinese governments assign serviceability levels to cable-stayed bridges based on the deflection at mid-span of the bridge deck, which is less than L/2000 and L/400, respectively [12,17].…”