Finite element model updating for the Tsing Ma Bridge tower based on surrogate models

This paper investigates the efficiency of three surrogate model-based dynamic finite element model updating methods, the response surface, the support vector regression, and the radial basis function neural network, using the engineering background of the Tsing Ma Bridge tower. The influences of two different sampling methods (central composite design sampling and Box–Behnken design sampling) on the model updating results are also assessed. It was deduced that the impact of the surrogate model type on the updating results is not significant. More precisely, the models updated using the response surface method and the support vector regression method are similar in terms of reproducing the dynamic characteristics of the physical truth. However, the effects of the employed sampling method on the model updating results are significant as the model updating quality using the central composite design sampling method is higher than that using the Box–Behnken design sampling method in some considered cases.

Design and Physical Detection of Bridge Tower and Externally Prestressing Cable for Existing Bridge Strengthened by A Cable-Stayed System

With the continuous development of economy, the increasing traffic volume has brought greater burden to highway bridges. In this paper, a Yellow River Bridge is taken as an example. The cracking and deflection of the box girder of the main bridge have affected the structural performance requirements of the bridge operation. Based on this situation, the cable-stayed system is used to reinforce the bridge, and the construction process of bridge tower, cable saddle, steel anchor box and external beam is described in detail. The theoretical calculation and practice show that this method can effectively strengthen the bridge structure, and the cable-stayed system reinforcement method, as a mature, reasonable and operable construction technology, provides relevant reference for the reinforcement research of similar bridges.

Mechanical Behavior of the Novel Gradient Concrete Tower of a Cable-Stayed Bridge

In this paper, the novel gradient concrete is innovatively applied to the bridge towers of Chizhou Yangtze River Bridge to solve the cracking and insufficient durability problems of concrete towers. Fiber-reinforced concrete is used in the outer functional area of the bridge tower, to significantly improve its crack resistance during construction and service. Moreover, the integrated design of anti-cracking and mechanical properties of tower materials is achieved. To study the performance of the novel functional gradient concrete (FGC) tower, the mechanical properties of the FGC tower material are tested, and the overall finite element stress is analyzed. Based on the material properties, the mechanical behavior of the cable-stayed bridge tower is studied. The temperature and stress of the FGC tower during the generation of the hydration heat are compared with that of the ordinary concrete tower. The crack resistance of the FGC tower is analyzed by the finite element method. The results show that the FGC tower has good mechanical properties and durability for the cable-stayed bridge towers.

Experimental study on dynamic effect of freestanding tower of sea-crossing bridge under wave load

There is a debate over whether the sea-crossing bridges undergo dynamic motions when exposed to wave loads. In order to verify the dynamic effect of the tower of sea-crossing bridge under wave load, an experimental study on dynamic effect of a freestanding tower of sea-crossing bridge is accomplished in this paper. Firstly, a test model for a typical bridge tower of pile group foundation under wave load is established by using a scale of 1:100. Secondly, a typical sea condition is designed for the response test of the bridge tower under wave load. The test results indicated that obvious vibration of top the tower occurs when the wave load period is close to the natural vibration period of the structure, and both displacement and base shear are amplified. The results in this paper will provide an important reference for whether the dynamic effect of wave load should be considered in the designs of bridge structure under wave load.

Wind Tunnel Test on Local Wind Field around the Bridge Tower of a Truss Girder

The aerodynamic performance of vehicles on a bridge deck depends on the local wind field, especially in a region near a bridge tower. This study was carried out on a large-scale (1: 20.4) truss girder, and wind tunnel tests were performed to determine how the wind fields were affected by the bridge tower in the presence of different wind barriers. The wind barrier parameters significantly affect the wind field. Wind barriers should be sufficiently high to provide a wide protection range and have relatively small porosities to reduce the wind speed. The opening form of the wind barrier should also be considered, where a circular-holed form reduces the wind speed and turbulence more than a horizontal-slatted form. The wind field is affected by structures and bridge towers on the deck. A turning point in the wind speed occurs at a measurement point near the bridge tower, and this point gradually moves upward towards lanes on the leeward side of the bridge. The equivalent wind speed is significantly reduced over a four-meter height range because of shadowing from the bridge tower and the wind barrier.

The design of super long span pedestrian landscape cable stayed bridge with sightseeing bridge tower

According to the design requirements of the super long-span pedestrian landscape cable-stayed bridge in Lake view Park, a kind of sightseeing tower-style pedestrian landscape three-tower cable-stayed bridge structure system was proposed. Sightseeing tower type bridge tower structure and duck egg arched bridge tower replace traditional cable-stayed bridge tower structure. Through the establishment of Midas finite element analysis model, dynamic modal analysis research was carried out. The analysis shows that: the sightseeing tower structure and the cable-stayed bridge tower structure are combined into one, and the two have good structural matching.

Design and analysis of the Wing-spread Bridge: a pedestrian bridge in the Binjiang Avenue, Shanghai

<p>Along Binjiang Avenue, the landscape in Shanghai, China, a footbridge is needed to connect the two sides of the Qiantanyoucheng park. In this paper, the "Wing-spread Bridge" is designed and analyzed based on the environment and human requirements. The initial inspiration for this bridge comes from the stress ribbon structure. In the Wing-spread Bridge's structural design, the stress ribbon and arch are combined to reduce both components' horizontal force. Meanwhile, abutment, arch foot, and bridge tower are combined as one tower, and this tower is shaped like a dove according to the surrounding natural conditions. The combination and adjustment of the components make the structure beautiful and competitive in the landscape. Finally, this bridge's FE model is established, and the static is carried out based on it. The results show that the bridge can meet the specification requirements in static aspects.</p>