Abstract
As seismic research advances, the concept of seismic design that prioritizes both structural safety and post-earthquake operational functions has received increasing attention. Numerous high-performance structural systems with redundant members or damage-reduction elements have emerged continuously, and the structural function degrades progressively as different seismic defense lines are compromised. Therefore, this paper proposes a gradient functional seismic design method suitable for high-performance structures. By managing the damage sequence and degree of different seismic fortification lines in the structure, the structural function is reduced according to the expected gradient, ensuring structural resilience under different level of seismic fortification. This method categorizes the functional gradient into three stages: serviceability, damage control, and collapse prevention. By correlating structural function with component damage, the method translates the desired functional targets of the structure into specific damage targets for each component, establishing a seismic design process that considers diverse functional goals. The results of numerical example demonstrate the accuracy and practicability of this method.
Address
Ding-Hao Yu, Yuhuan Zhang, Cheng Zhou, Yaqiang Zhang and Gang Li: State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology,
Dalian 116024, China
Abstract
Based on the finite element analysis software ABAQUS, a model of a reinforced concrete bridge is built. Using the time-history analysis method, the effects of the material strain rate on the spatial seismic response of the bridge are studied. The displacement time-history curves of the pier top and the shear force time-history curves of the pier base are plotted, and the dynamic responses of the bridge under consistent excitation and multi-support excitation are compared. The results indicate that when only the effects of material strain rate are considered, the displacement of the pier top is reduced and the shear force of the pier base is increased. When only the spatial effects of earthquake motion are considered, both the displacement value of the pier top and the shear force of the pier base are amplified. However, the strain rate effects of materials weaken the impact of seismic spatial effects on the pier displacement of the bridge to a certain degree.
Key Words
consistent excitation; multi-support excitation; seismic performance of bridge; strain rate
Address
Min Li: School of Marine and Civil Engineering, Dalian Ocean University, Dalian, 116023, China
Liwei Shi: Beijing uni-construction group CO., LTD. Beijing, 100000, China
Abstract
In order to fully utilize the advantages of large construction tolerance of socket connection and self-recovery of prestressed connection after earthquakes, a hybrid connection prefabricated assembled bridge pier (PCSC) with socket connection and prestressed reinforcement connection is proposed. Based on the actual engineering bridge pier, a finite element model of the pier was established using a fiber model, and the accuracy of the numerical model was verified by the in-situ full-scale test results. The performance indicators such as damage failure mode, hysteresis behavior, skeleton curve, energy dissipation capacity, equivalent stiffness, and residual displacement of the hybrid connected bridge pier was Analyzed. The results indicate that the failure mode of the PCSC bridge pier specimen is bending failure. The numerical analysis model established in this study can reproduce the experimental results well. The load displacement curve of PCSC bridge piers is roughly trilinear, and there is still a certain strengthening stage after yielding, with nonlinear inflection points and strength decline points. Compared with traditional cast-in-place (CIP) bridge pier, the configuration of unbonded post tensioned prestressed tendons in reinforced concrete hollow bridge piers greatly compensates for the weakened peak load and post yield stiffness of the piers due to the presence of connection, prolongs their yield point, improves ductility, yield strength, and horizontal resistance. The PCSC bridge piers exhibit weaker energy dissipation capacity. The prestressed tendons reduce the equivalent damping ratio of the bridge pier, increases the equivalent stiffness of the bridge pier, and has little effect on the residual displacement of the bridge pier.
Key Words
fiber model; in situ full-scale test; prefabricated connection; segmental bridge piers; socket connection
Address
Chongbin Zhang: China Railway Engineering Design and Consulting Group Co., Ltd., Beijing, China
Shuang Zou and Heisha Wenliuhan: Earthquake Engineering Research & Test Center, Guangzhou University, Guangzhou, Guangdong, China;
Key laboratory of Earthquake Engineering and Applied Technology in Guangdong Province,
Guangzhou, China
Abstract
This study presents a novel self-centering rotational deformation amplification function brace (RDAF-SCB) that is based on the bridge amplification working mechanism. Compared with conventional brace, RDAF-SCB can solve the problem that the conventional self-centering brace has insufficient energy dissipation ability and the deformation amplification damper lacks self-centering function. This paper introduces the basic structure and working mechanism of RDAF-SCB, and conducts low-cycle reversed loading tests on 6 groups of RDAF-SCB specimens under different working conditions to obtain and compare the key performance data of RDAF-SCB, including bearing capacity and hysteretic curve. A numerical simulation is conducted to analyze the influence of key factors on the mechanical behavior of the RDAF-SCB. The results indicate that the established finite element model agrees nicely with the test results, as the initial amplification angle decreases, the RDAF-SCB exhibits better energy dissipation capacity and fuller hysteresis curve. Compared with the model with an initial amplification angle of 45, the RDAF-SCB with an initial amplification angle of 22.5 increases the force by 34.3%, the equivalent viscous damping ratio by 46.1%, and the maximal residual displacement ratio by 73.95% at the maximal forward displacement; when the initial amplification angle is unchanged, increasing the initial pre-pressure of the disc springs increases bearing capacity and decreases the residual deformation; with the increase of the preload force of the bolts, the energy dissipation capacity of the brace is enhanced and the residual deformation is slightly increased.
Key Words
deformation amplification; energy dissipation; residual deformation; self-centering
Address
De-Bin Wang, Ping-Fan Zhang, Shi-Peng Wang and Qi-Yan Tan: School of Traffic Engineering, Dalian Jiaotong University, Dalian 116028, China
Abstract
This paper proposes an innovative methodology that synergistically combines machine learning techniques with probabilistic learning on manifolds for generating samples to predict the response distribution of frame structures. Through a rigorous feature engineering process, 11 seismic feature parameters and one structural feature parameter were judiciously selected. Leveraging a small-scale dataset, an exhaustive model selection process was undertaken, evaluating the performance of Support Vector Regression, Random Forest, and Gradient Boosting Trees, ultimately identifying the optimal machine learning model. By concurrently accounting for the stochastic nature of seismic motions and structural characteristics, this methodology is employed to predict the distribution of structural responses of multi-story reinforced concrete frame structures subjected to stochastic seismic events. The results demonstrate that this methodology achieves a high degree of prediction accuracy on the test dataset and can reasonably predict the seismic damage to reinforced concrete frame structures, thereby providing valuable guidance for post-earthquake disaster assessment and emergency response efforts.
Key Words
K-means clustering; machine learning; probabilistic learning on manifolds; random seismic response prediction
Address
Zheng Wu, Meiling Xiao, Yiwu Sun and Houming Wang: School of Architecture and Planning, Yunnan University, Kunming 650051, P.R. China
Abstract
Appropriately utilizing the data recorded by the bridge health monitoring (BHM) system to identify structural damage, evaluate structural safety, and predict structural serviceability is the core work in the community of BHM. Neural network models are more flexible to describe multi-source, multi-dimension and non-linear relationships, comparing with traditional statistical and regression analysis, and have been widely used for data-driven evaluation of bridge performance. But it is easily influenced by noise and errors that are difficult to eliminate in the monitoring data. Physics-guided neural networks (PGNNs), which combine physical information with neural networks, have stronger accuracy, robustness, and reliability, and are becoming promising tools for bridge performance evaluation. In the past few years, numerous researchers all over the world paid intensive attention on this topic. This paper summarizes the latest developments of PGNN methods for BHM. The commonly used PGNNs are classified into three categories, including the physics-guided loss function, the physical data enhancement and the digital twin. Following that, the applications of the three types of PGNNs are presented through a summary of relevant literature. Finally, the challenges and prospects of PGNN methods in the field of BHM are discussed.
Key Words
artificial neural network; bridge health monitoring; digital twin; physics-guided neural network; structural safety evaluation
Address
Guang-Dong Zhou, Jia-Ming Chen, Jia-Huan Xi and Hong-Li Zhou: College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China
