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Effect of Blasting Stress Wave on Dynamic Crack Propagation

Computer Modeling in Engineering & Sciences 2024年第1期138卷 349-368页

作者： Huizhen Liu Duanying Wan Meng Wang Zheming Zhu Liyun Yang Key Laboratory for Old Bridge Detection&Reinforcement Technology of the Ministry of Transportation Beijing100088China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing100083China MOE Key Laboratory of Deep Underground Science and Engineering School of Architecture and EnvironmentSichuan UniversityChengdu610065China

Stress waves affect the stress field at the crack tip and dominate the dynamic crack ***,evaluating the influence of blasting stress waves on the crack propagation behavior and the mechanical characteristics of crack propagation is of great significance for engineering *** this study,ANSYS/LS-DYNA was used for blasting numerical simulation,in which the propagation characteristics of blasting stress waves and stress field distribution at the crack tip were closely ***,ABAQUS was applied for simulating the crack propagation path and calculating dynamic stress intensity factors(DSIFs).The universal function was calculated by the *** results show that:the compressive wave causes the crack to close and the reflected tensile wave drives the crack to initiate and propagate,and failure mode is mainly tensile *** crack propagation velocity varies with time,which increases at first and then decreases,and the crack arrest occurs due to the attenuation of stress waves and dissipation of the blasting *** addition,crack arrest toughness is smaller than the crack initiation toughness,applied pressure waveforms(such as the peak pressure,duration,waveforms,wavelengths and loading rates)have a great influence on *** is conducive to our deep understanding or the study of blasting stress waves dominated fracture,suggesting a broad reference for the further development of rock blasting in engineering practice.

关键词： Crack propagation blasting stress wave dynamic stress intensity factor pressure waveform numerical simulation

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Evaluation Method of Bearing Capacity of Concrete Structure

Evaluation Method of Bearing Capacity of Concrete Structure

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2024 世界交通运输大会

作者： Junpeng Xing Zechen Zhang Yubo Wang Yugeng Xu Key Laboratory for Old Bridge Detection and Reinforcement Technology of Ministry of Transportation

In the process of using concrete bridge structures,due to the influence of environmental and internal material factors,with the passage of time,materials will gradually age,structural performance will deteriorate,and structures will experience damage or even *** reinforced concrete structures,the main manifestations include concrete carbonation,reinforcement corrosion,deterioration of mechanical properties of corroded reinforcements,and the appearance and development of structural *** prestressed concrete structures,the main manifestations include concrete deterioration,corrosion of prestressing tendons and ordinary reinforcement,reduction in effective prestress,degradation of mechanical properties of corroded reinforcements,weakening of bond strength between corroded reinforcements and concrete,as well as the appearance and development of structural *** determine the safety,durability,and normal functional use of bridges,it is necessary to inspect and evaluate in-service prestressed concrete *** paper summarizes existing crack detection methods and introduces evaluation methods for reinforced concrete structures based on crack statistical *** introduces performance evaluation indicators for prestressed concrete structures and explains how to use these indicators to evaluate prestressed concrete structures.

关键词： bridge engineering Highway bridges detection techniques Evaluation methods

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Study on the Seismic Performance of Prefabricated Double-Column Piers by Finite Element Analysis 9

Study on the Seismic Performance of Prefabricated Double-Col...

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9th International Technical Conference on Frontiers of Hydraulic and Civil Engineering technology, HCET 2024

作者： Yin, Shujun Zhang, Qiang Fei, Wen Zhou, Mi Key Laboratory for Old Bridge Detection and Reinforcement Technology Ministry of Transportation Chang’an University Xi’an710064 China Shanxi Transportation Research Institute Group Co. Ltd Taiyuan030006 China

ISBN: (纸本)9781643685595

Prefabricated assembled bridge piers have certain differences in their mechanical behavior under seismic loads due to the existence of joints, which limits their development and application in high-intensity seismic areas compared to cast-in-place bridge piers. This paper focuses on the structural design of prefabricated double-column piers that are connected by grouting sleeves at both the top and bottom joints. Based on this, grouting sleeve joint specimen pullout tests were designed and implemented to investigate the effect of grouting defects on their mechanical properties. Furthermore, finite element analysis was conducted on the designed pier model using ABAQUS software. The results indicate that defects with a length of 2.5 times the diameter of the reinforcement are sufficient to cause a change in the damage pattern of the member. Under cyclic horizontal loads, the damage initially occurs at the top and bottom of the piers and eventually the plastic hinges forms at the joints. The contact surface between the bottom of the piers and the seat grout layer undergoes opening behavior. The failure modes of two columns exhibit a certain degree of symmetry. Compared to the prefabricated double-column pier with a stirrup ratio of 0.55%, the load-carrying capacity improves slightly for the piers with stirrup ratios of 0.86% and 1.24%. When the axial compression ratio is 0.05 and 0.1, the load-displacement curves are almost identical. When the axial compression ratio is 0.2, the descent phase of the load-displacement curve of the prefabricated double-column pier is slightly more apparent, but the overall difference is small. It can be concluded that the influence of the stirrup ratio on the seismic performance of this double-column pier type is greater than that of the axial compression ratio. © 2024 The Authors.

关键词： Grouting

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Research on Transverse Restraint System of Cable-stayed bridge under Ultra High Performance Concrete Deck Pavement 14

Research on Transverse Restraint System of Cable-stayed Brid...

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14th International Conference on Intelligent Computation technology and Automation, ICICTA 2021

作者： Zhou, M. Liu, Y. Gao, M. Zhu, G.Q. Key Laboratory for Bridge Detection and Reinforcement Technology of the Ministry of Transportation Chang'an University Shanxi Xi'an710064 China

In order to explore the optimal lateral restraint system for long-span cable-stayed bridges under ultra-high performance concrete deck pavement. This paper takes a UHPC deck pavement cable-stayed bridge as an example, selects four different lateral restraint systems, calculates the stress of each key section of the cable-stayed bridge under the action of an earthquake, and then selects the optimal lateral Constraint system. The research results show that when ultra-high performance concrete is used as the bridge deck pavement, the increase in the quality of the bridge deck system will have a greater adverse effect on the seismic performance of the bridge. Compare the internal force response and displacement response at each key section of the bridge under four different lateral restraint systems under earthquake action. Compared with the other three systems, the internal force response and displacement response value of the horizontal cable system is smaller, and the energy dissipation and shock absorption effect is better. For cable-stayed bridges using ultra-high performance concrete as the deck pavement, in the selection of the lateral restraint system, a restraint system of cables is set between the towers and beams, which can better reduce the impact of the increase in the quality of the bridge deck on the seismic performance of the bridge, is the most reasonable horizontal restraint method. Considering the internal force and displacement response of the bridge structure and the safety of the support under the earthquake, the parameter selection of the cable support is k = 135000 kN/m and S = 0.4 m. © 2022 Institute of Physics Publishing. All rights reserved.

关键词： Cable stayed bridges

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Reliability Evaluation of Prestressed Concrete Simple Support Girder bridges

Reliability Evaluation of Prestressed Concrete Simple Suppor...

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2023世界交通运输大会(WTC2023)

作者： Yabin Gao Xinze Wang Shihao Xin Key Laboratory for Old Bridge Detection and Reinforcement Technology of Ministry of Transportation Chang'an University

In order to deeply study the bearing performance of prestressed concrete simple support beams,this paper comprehensively analyzes the shear bearing capacity of the structure from the perspective of fixed value calculation and ***,the finite element model is established,and the resistance and effect of the most unfavorable components are calculated by using the fixed value calculation ***,the random variables affecting the shear bearing capacity of the structure are analyzed,and their distribution types are ***,the calculated reliable indicator of shear resistance is compared with the *** results of the calculations show that:under the original design conditions,from the perspective of fixed value calculation,there is a 15% safety reserve of the structure From the perspective of reliability,the shear reliability index 5.5 of the structural side beam also meets the requirements of the *** is a certain amount of redundancy,and there is room for optimization,which can provide suggestions for subsequent related designs.

关键词： Prestressed concrete Simple support beam Reliability Ultimate limit state of load capacity

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Analysis and Correction of Temperature Effect of PC Cable-Stayed bridge during Construction

Analysis and Correction of Temperature Effect of PC Cable-St...

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2022世界交通运输大会(WTC2022)

作者： Siyu Zhu Yifan Song Hanhao Zhang Huichen Ge Kang Wang Qixiang Hui Fuhua Zhang Highway College Key Laboratory of Bridge Detection Reinforcement Technology Ministry of CommunicationChang'an University

In order to study the influence of temperature effect on main beam alignment and cable force in cable-stayed bridge construction process:,this paper analyses the characteristics of temperature field of main beam and cable,based on the basic theory of heat conduction,a simulation calculation method of structure plane temperature field is *** method can easily and accurately calculate and predict the temperature field distribution of girder and stay *** analyses the influence of structure temperature field on cable force and line shape through temperature field distribution obtained by simulation *** influence of temperature effect on subsequent unmade segments is predicted and a method to correct the influence of temperature effect is proposed according to the actual alignment of the *** a cable-stayed bridge(Jun'an Waterway bridge)as an example,the temperature field simulation results obtained in this paper are very similar to the actual measured temperature *** method of correcting temperature effect in this paper ensures the rationality of main beam alignment and cable force.

关键词： Highway bridge Plane temperature Field simulation Field test Temperature effect Correction method Cable force Elevation error

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Seismic Performance of Precast Uhpc Pipe Pile with Two Pile-Cap Beam Connection Types: An Experimental and Numerical Study

SSRN

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SSRN 2024年

作者： Zhou, Mi Zhao, Xiaonan Song, Jianwei Xu, Zitao Yin, Shujun Zhu, Guoqiang Key Laboratory for Old Bridge Detection and Reinforcement Technology Ministry of Transportation Chang’an University Xi’an710064 China Department of Civil Structural and Environmental Engineering University at Buffalo BuffaloNY14260 United States

To develop an effective pile foundation scheme for earthquake-prone regions, this study introduces a novel pile structure that integrates ultra-high-performance concrete (UHPC) with traditional prestressed high-strength concrete (PHC) pipe piles. The research focuses on assessing the impact of various connection forms between the pile and cap beam on the seismic performance of bridge substructures. Two 1/3-scale specimens were meticulously designed and tested: one featuring a cast-in-place (CIP) connection and the other incorporating precast assembly (PA) connection between the pipe pile and cap beam. Pseudo-static tests were conducted to evaluate the failure mode, lateral capacity, ductility, energy dissipation ability, and residual displacement of UHPC pipe piles with the two connection forms. The results indicate that the specimen with a CIP connection exhibits a higher horizontal load capacity and stronger energy dissipation ability, while the specimen with the PA connection displays superior self-centering ability, increased ductility, and causes less damage to the cap beam. Finally, finite element models were developed to analyze the effects of design parameters on the seismic performance of the pile connected by the two methods. This research may provide valuable design guidance for incorporating UHPC in pile foundations. To facilitate its practical implementation in engineering projects, further theoretical and experimental research is recommended in this paper. © 2024, The Authors. All rights reserved.

关键词： Piles

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Research on Bending Performance of RC Beams Reinforced by Prestressed TRM 14

Research on Bending Performance of RC Beams Reinforced by Pr...

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14th International Conference on Intelligent Computation technology and Automation, ICICTA 2021

作者： Ren, W. Zhang, H. Liu, H. Key Laboratory of Bridge Detection Reinforcement Technology Ministry of Transport Chang'an University Shaanxi Xi'an710064 China Road and Bridge International CO. LTD. Beijing100000 China Jining Hongxiang Highway Survey and Design CO. LTD. Shandong Jining272000 China

To solve the problems of Low material strength utilization rate and unsatisfactory reinforcement effect in the concrete structure reinforced by bonding method, the self-developed tensioning and anchoring equipment was used to carry out the experimental study of prestressed TRM reinforcement for RC beams. The influence of prestressing TRM on bearing capacity, fracture characteristics and ductility were studied through 3 RC beam tests. It was concluded that the crack load, yield load and ultimate load can be significantly increased by prestressing TRM reinforcement, and the yield load can be increased by more than 30%. The prestressed TRM reinforcement beam had a good constraint effect on the cracks of the beam;After TRM reinforcement, the ductility of beams decreased to a certain extent. In this paper, the final failure of the test beam was caused by the tensile failure of the fiber textile, and the yield load of the beam increases obviously, which indicates that the prestressing force on the fiber textile can effectively improve the strength utilization ratio of the material. © 2022 Institute of Physics Publishing. All rights reserved.

关键词： Bearing capacity

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Study on reasonable restraint system of double-deck frame bridge subjected to seismic action 14

Study on reasonable restraint system of double-deck frame br...

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14th International Conference on Intelligent Computation technology and Automation, ICICTA 2021

作者： Zong, X.M. Liu, Y. Yang, F. Wu, J. Wang, X.D. Zhou, M. China United Northwest Institute for Engineering Design and Research Co. Ltd Shanxi 710077 China Key Laboratory for Bridge Detection and Reinforcement Technology of the Ministry of Transportation Chang'an University Shanxi Xi'an710064 China Guangdong Communication Planning &Design Institute Co. Ltd. Guang Dong Guangzhou510507 China

In this paper, in order to improve the seismic performance of frame type double deck overpass bridge under seismic action, the most reasonable restraint system of frame double-deck overpass is studied. Based on the typical frame-type double-deck continuous overpass-hushen bridge, the finite element analysis model of the solid bridge is established. Then, from six different directions, eight different constraint combinations are established. Finally, through the analysis of the bridge direction control point of the internal force, displacement and other parameters, research and contrast the frame double-deck overpass under different constraints of the seismic response. The results show that the combination of rubber bearing, steel wire rope and concrete block can effectively limit the relative displacement between piers and beams, and reduce the internal force response of Piers and residual deformation of supports. © 2022 Institute of Physics Publishing. All rights reserved.

关键词： Piers

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Fluid-solid coupling effect of different forms of deep-water piers under earthquake

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Zhendong yu Chongji/Journal of Vibration and Shock 2022年第21期41卷 7-18页

作者： Zhou, Mi Jiang, Run Li, Jiulong Key Laboratory for Old Bridge Detection and Reinforcement Technology The Ministry of Transportation Chang'an University Xi'an710064 China Zhejiang Jiaogong Advanced-Grade Highway Maintenance Co. Ltd. Hangzhou310051 China China Design Group Co. Ltd. Nanjing210014 China

Under action of earthquake, water-structure interaction effect makes submerged part of structure produce hydrodynamic pressure. Here, to study effects of hydrodynamic effect on seismic responses of different forms of piers, and distribution laws of hydrodynamic pressure on piers, taking a large round pier, a rectangular pier and a pile group foundation with high pile cap as examples, fluid-solid coupling numerical calculation models for 3 examples were established by using the finite element method based on potential fluid, and their natural vibration characteristics analyses, seismic response analyses and hydrodynamic pressure analyses under different water depth conditions and different seismic wave inputs were performed. The results showed that increase in water depth can reduce natural vibration frequencies and increase internal force responses of 3 pier-forms;upstream surface of rectangular pier in direction of earthquake input is plane, interaction between rectangular pier and water is more obvious than that between circular pier and water, and this interaction can produce larger hydrodynamic pressure;when a certain water depth is reached, hydrodynamic pressure on circular and rectangular piers firstly increases and then decreases along pier height;hydrodynamic pressure at center position of upstream surface is the largest and gradually decreases to both sides;seismic response and hydrodynamic pressure of middle pile of pile group foundation with underwater high pile cap are smaller than those of side piles;after water depth submerges pile cap, pile cap bears most of hydrodynamic pressure, and action point of total hydrodynamic pressure on pile foundation is at position of 0.6 pile length. © 2022 Chinese Vibration Engineering Society. All rights reserved.

关键词： Seismic response

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