Binzhou Yellow River Highway Bridge Research Articles

PERFORMANCE VARIATIONS OF A CABLE-STAYED BRIDGE WITH DAMAGED CABLES

A cable-stayed bridge model was made based on the design drawings of Shandong Binzhou Yellow River Highway Bridge (BZB) and detailed model tests were conducted. In the tests, the cable damage effects on the loading behavior and dynamic performance of the bridge model were studied by considering different cable damages' locations, different numbers of damaged cables, and different damaged levels of cables etc. The experimental results revealed that the cable damages may significantly affect the internal forces of other cables and the stress distributions of the girders; however, they have less influence on the natural frequencies of the bridge model. In parallel with the model tests, a finite element model of the bridge structure has been established. Numerical analysis for the bridge model with cable damages was carried out to validate the experimental results and explain the phenomena observed in the model tests.

Structural Damage Detection by Integrating Non-Negative Matrix Factorization and Relevance Vector Machines

This paper proposes a structural damage detection method based on wavelet packet decomposition, non-negative matrix factorization (NMF) and a relevance vector machine (RVM). First, vibration data at multiple points are used to calculate the wavelet packet node energies and construct a non-negative damage feature matrix. Second, to increase the damage detection accuracy, the NMF technique is employed to obtain the reduced dimensional representation of the non-negative damage feature matrix and extract the underlying features. Last, the RVM, a powerful tool for classification and regression, that can obtain the probability estimation for classification, is used to determine the relationship between features extracted with NMF and the corresponding damage patterns by considering the measurement noise. The trained RVMs are then used to perform damage pattern identification and classification of an unknown state structure. Numerical study on the Binzhou Yellow River Highway Bridge is carried out to validate the ability of the proposed method in damage detection. The results show that the RVM can achieve a high accuracy in damage pattern identification accuracy using the features extracted by NMF.

Traffic load modelling based on structural health monitoring data

Live and fatigue load models are foundations for the life-cycle design of highway bridges. Many highway bridges are now equipped with structural health monitoring (SHM) systems, which provide valuable data to establish load models. In this paper, traffic load models of the Binzhou Yellow River Highway Bridge are developed based on the field measurement of vehicles by an existing SHM system. The probabilistic distribution model and extreme value distribution of gross vehicle weight are statistically analysed using the monitoring data. The results indicate that they follow the bimodal lognormal and Gumbel distributions, respectively. The fatigue load spectrum is also studied. The logistic model is employed to predict the long-term traffic volume, and its parameters of the logistic model are updated using the monitored traffic volume. The combination of the fatigue load spectrum and the traffic volume forecast using the updated logistic model provides a load model for estimation of fatigue damage evolution of bridges.

Analysis of capability for semi-active or passive damping systems to achieve the performance of active control systems

Linear quadratic regulator (LQR)-based control force is composed of an elastic restoring force component and a damping force component. According to the analysis of the proportions of the elastic restoring force and the damping force to the total active control force, two indices are defined to quantify the damping characteristics and negative stiffness characteristics of an active control force. Because a semi-active damping system behaves like a damping device with adjustable parameters, these two indices can be used to quantify the capability of a semi-active damping system and a passive damping system achieving the performance of a fully active control system. Numerical studies are conducted to investigate the damping characteristics and negative stiffness characteristics of an active control force in an active control system. Semi-active damping systems and passive damping systems are designed to replace the active control systems and then the capability of the semi-active control and passive control achieving the performance of fully active control is further studied through the numerical study. Finally, the negative stiffness characteristics realized by semi-active magnetorheological (MR) damping systems are demonstrated through an in situ field test of a stay cable in the Binzhou Yellow River Highway Bridge. Copyright © 2010 John Wiley & Sons, Ltd.

Application of Compressive Sampling for Accelerometer Signals Used in Structural Health Monitoring

In structural health monitoring (SHM) of civil structures, data compression is often needed for saving the cost of data transfer and storage because of the large volumes of sensor data generated from the monitoring system. The traditional framework for data compression is to first sample the full signal, then to compress it. Recently, a new data compression method named compressive sampling (CS) has been presented, that can acquire the data directly in compressed form by using special sensors. In this paper, the potential of CS for data compression of vibration data is investigated using simulation of the CS sensor algorithm. The acceleration data collected from the SHM system of Shandong Binzhou Yellow River Highway Bridge is used to analyse the data compression ability of CS. For comparison, the wavelet transform based and Huffman coding methods are also employed to compress the data. The results show that CS is useful for compression of vibration data in SHM of civil structures.

Structural damage identification based on integration of information fusion and shannon entropy

This paper proposes a damage identification method based on the combination of artificial neural network (ANN), Dempster–Shafer (D–S) evidence theory-based information fusion and the Shannon entropy, to form a weighted and selective information fusion technique to reduce the impact of uncertainties on damage identification. The initial damage decision is first made by several individual ANNs with different inputs. Considering that damage identification accuracy is dependent on different ANNs, optimal weighting coefficients obtained by genetic algorithm (GA) are assigned to ANNs. The decision obtained from the ANN with the largest weighting coefficient is the most reliable. Damage identification-based D–S evidence theory is carried out by combining the decision of the ANN with the largest weighting coefficient with that of the ANN with the second largest weighting coefficient. Next, Shannon entropies of the decisions of the ANN with the largest weighting coefficient and that obtained by the information fusion are calculated to measure the uncertainty level of the decisions, respectively. The decision with smallest entropy remains in the next information fusion operation because this decision has less uncertainty. The decision with smaller entropy will be combined with the decision of the ANN with the third largest weighting coefficient. The operation is repeated until the last ANN with the minimum-weighting coefficient is fused. Numerical study on the Binzhou Yellow River Highway Bridge was carried out to validate the accuracy of the proposed damage identification method. The simulated results indicate that the damage identification method based on the weighted and selective information fusion technique can improve damage identification accuracy in comparison with ANN alone and direct information fusion techniques when the measurement noise level is the same.

Vibration Control of Stay Cables of the Shandong Binzhou Yellow River Highway Bridge Using Magnetorheological Fluid Dampers

The Shandong Binzhou Yellow River Highway Bridge is a three-tower, cable-stayed bridge in Shandong Province, China. Because the stay cables are prone to vibration, 40 magnetorheological (MR) fluid dampers were attached to the 20 longest cables of this bridge to suppress possible vibration. An innovative control algorithm for active and semiactive control of mass-distributed dynamic systems, e.g., stay cables, was proposed. The frequencies and modal damping ratios of the unimpeded tested cable were identified through an ambient vibration test and free vibration tests, respectively. Subsequently, a series of field tests were carried out to investigate the control efficacy of the free cable vibrations achieved by semiactive MR dampers, “Passive-off” MR dampers and “Passive-on” MR dampers. The first three modal damping ratios of the cable incorporated with the MR dampers were also identified from the in situ experiments. The field experiment results indicated that the semiactive MR dampers can provide significantly greater supplemental damping for the cable than either the Passive-off or the Passive-on MR dampers because of the pseudonegative stiffness generated by the semiactive MR dampers.

Papers in This Issue

The July 2007 issue of the Journal of Bridge Engineering begins with a paper on vibration of stay cables. In “Vibration Control of Stay Cables of Shandong Binzhou Yellow River Highway Bridge Using Magnetorheological Fluid Dampers,” Li, Liu, Li, Guan, and Ou describe the use of an innovative control algorithm for active and semiactive control of mass-distributed dynamic systems. The longest cables of the Shandong Binzhou Yellow River Highway Bridge were stabilized to suppress vibration using 40 magnetorheological fluid dampers. Field tests were carried out and determined that the semiactive magnetorheological dampers can provide greater supplemental damping than “passive-on” or “passive-off” dampers. Next are three papers on bridge desks. In the first one by Oh, Lew, and Choi, the issue of safety of deck slabs and the resulting frequent repair and strengthening is investigated. In “Realistic Assessment for Safety and Service Life of Reinforced Concrete Decks in Girder Bridges,” the development of a realistic assessment system that can estimate the safety and remaining service life of concrete bridge decks is presented. By determining a realistic and accurate assessment of the bridge deck, the cost of repairs can be eliminated and the loss of use to the public during possibly unnecessary repairs can be prevented. The proposed method uses an assessment of corrosion along with analysis of flexture, shear, and fatigue. The second bridge deck paper is titled “Low-Cycle Fatigue Testing of High-Performance Concrete Bonded Overlay-Bridge Deck Slab Systems” and is authored by Issa, Alhassan, and Shabila. This paper describes a field performance evaluation of a full-scale prototype bridge deck using plain and fibrous latex– modified concrete and microsilica concrete overlays. The study found that this overlay provided good results. “Stiffness and Strength of Metal Bridge Deck Forms,” by Egilmez, Helwig, Jetann, and Lowery, is the final paper on bridge decks. This paper presents the results of the first phase of research investigating the bracing behavior of metal bridge deck forms. While the bracing effects of these forms are used in building construction, due to connection details, the bracing effects are normally not considered when these forms are used in bridge construction. Shear diaphragm tests were conducted to determine the shear stiffness and strength of the forms. The experimental results on the diaphragms indicate the potential for the bracing of steel bridge girders using metal deck forms. The fifth paper in this issue of the Journal of Bridge Engineering is about bridge expansion joints. Malla, Shaw, Shrestha, and Brijmohan in “Development and Laboratory Analysis of Silicone Foam Sealant for Bridge Expansion Joints,” present the results of the development of an elastomeric foam-type joint sealant for use in small-movement bridge expansion joints. The paper presents the results of an investigation using both foam and solid sealants. “Deck-Mounted Steel Post Barrier System,” by Reid, Faller, and Hascall, presents the results of an evaluation of an existing mountable safety barrier system on a fiber-reinforced plastic

Structural Health Monitoring System for the Shandong Binzhou Yellow River Highway Bridge

The Binzhou Yellow River Highway Bridge is a cable-stayed bridge in China. A structural health monitoring system was implemented on this bridge during its construction for monitoring its structural health status and assessing its safety for long-term service. This paper describes the design, implementation and functions of this system, and presents the measured responses of the bridge subjected to moving vehicle loads. The system includes a sensor module, a data acquisition module, a wired and wireless data transmit module, a structural analysis module, a database module, and a warning module. It is integrated by using LabVIEW software and can be remotely operated via Internet. After two years of service, the system operates well and confirms the current reliability of the bridge.