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Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon compositeconnections

《结构与土木工程前沿（英文）》   页码 827-854 doi: 10.1007/s11709-023-0954-1

摘要： The seismic performance of a fully fabricated bridge is a key factor limiting its application. In this study, a fiber element model of a fabricated concrete pier with grouting sleeve-prestressed tendon composite connections was built and verified. A numerical analysis of three types of continuous girder bridges was conducted with different piers: a cast-in-place reinforced concrete pier, a grouting sleeve-fabricated pier, and a grouting sleeve-prestressed tendon composite fabricated pier. Furthermore, the seismic performance of the composite fabricated pier was investigated. The results show that the OpenSees fiber element model can successfully simulate the hysteresis behavior and failure mode of the grouted sleeve-fabricated pier. Under traditional non-near-fault ground motions, the pier top displacements of the grouting sleeve-fabricated pier and the composite fabricated pier were less than those of the cast-in-place reinforced concrete pier. The composite fabricated pier had a good self-centering capability. In addition, the plastic hinge zones of the grouting sleeve-fabricated pier and the composite fabricated pier shifted to the joint seam and upper edge of the grouting sleeve, respectively. The composite fabricated pier with optimal design parameters has good seismic performance and can be applied in high-intensity seismic areas; however, the influence of pile-soil interaction on its seismic performance should not be ignored.

关键词： seismic performance     continuous girder bridge     grouting sleeve-prestressed tendon composite connections     grouted sleeve connection     design parameters    

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3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 165-175 doi: 10.1007/s11709-018-0484-4

摘要： In this manuscript, we study fracture of prestressed cylindrical concrete pipes. Such concrete pipes play a major role in tunneling and underground engineering. The structure is modelled fully in 3D using three-dimensional continuum elements for the concrete structure which beam elements are employed to model the reinforcement. This allows the method to capture important phenomena compared to a pure shell model of concrete. A continuous approach to fracture is chosen when concrete is subjected to compressive loading while a combined continuous-discrete fracture method is employed in tension. The model is validated through comparisons with experimental data.

关键词： cylindrical concrete structures     limit state analysis     3D fracture modelling     prestressed composite pipes     reinforced concrete     three-point bending test    

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Nonlinear experimental response of non-conventional composite steel and concrete connection

Tobia ZORDAN, Bruno BRISEGHELLA

《结构与土木工程前沿（英文）》 2009年 第3卷 第1期   页码 42-49 doi: 10.1007/s11709-008-0058-y

摘要： An experiment was carried out on a set of full-scale specimens of a non-conventional connection between a concrete column and a composite steel and concrete beam defined on the basis of a number of requirements. The proposed connection, conceived in the ambit of semi-rigid joints, is aimed at combining general ease of construction with a highly simplified assembly procedure with a satisfying transmission of hogging moment at supports in continuous beams. For this purpose, the traditional shear studs used at the interface between the steel beam and the upper concrete slab, are also employed at the ends of the steel profiles welded horizontally to the end plates. The test is aimed at investigating the hogging moment response of the connection under incremental loads until failure.

关键词： composite connections     nonlinear behaviour     hogging moment     monotonic tests    

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Function-oriented optimization design method for underactuated tendon-driven humanoid prosthetic hand

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0696-0

摘要： The loss of hand functions in upper limb amputees severely restricts their mobility in daily life. Wearing a humanoid prosthetic hand would be an effective way of restoring lost hand functions. In a prosthetic hand design, replicating the natural and dexterous grasping functions with a few actuators remains a big challenge. In this study, a function-oriented optimization design (FOD) method is proposed for the design of a tendon-driven humanoid prosthetic hand. An optimization function of different functional conditions of full-phalanx contact, total contact force, and force isotropy was constructed based on the kinetostatic model of a prosthetic finger for the evaluation of grasping performance. Using a genetic algorithm, the optimal geometric parameters of the prosthetic finger could be determined for specific functional requirements. Optimal results reveal that the structure of the prosthetic finger is significantly different when designed for different functional requirements and grasping target sizes. A prosthetic finger was fabricated and tested with grasping experiments. The mean absolute percentage error between the theoretical value and the experimental result is less than 10%, demonstrating that the kinetostatic model of the prosthetic finger is effective and makes the FOD method possible. This study suggests that the FOD method enables the systematic evaluation of grasping performance for prosthetic hands in the design stage, which could improve the design efficiency and help prosthetic hands meet the design requirements.

关键词： function-oriented     tendon driven     prosthetic hand     optimization     humanoid     underactuated    

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Tissue engineering of cartilage, tendon and bone

null

《医学前沿（英文）》 2011年 第5卷 第1期   页码 61-69 doi: 10.1007/s11684-011-0122-1

摘要：

Tissue engineering aims to produce a functional tissue replacement to repair defects. Tissue reconstruction is an essential step toward the clinical application of engineered tissues. Significant progress has recently been achieved in this field. In our laboratory, we focus on construction of cartilage, tendon and bone. The purpose of this review was to summarize the advances in the engineering of these three tissues, particularly focusing on tissue regeneration and defect repair in our laboratory. In cartilage engineering, articular cartilage was reconstructed and defects were repaired in animal models. More sophisticated tissues, such as cartilage in the ear and trachea, were reconstructed both in vitro and in vivo with specific shapes and sizes. Engineered tendon was generated in vitro and in vivo in many animal models with tenocytes or dermal fibroblasts in combination with appropriate mechanical loading. Cranial and limb bone defects were also successfully regenerated and repaired in large animals. Based on sophisticated animal studies, several clinical trials of engineered bone have been launched with promising preliminary results, displaying the high potential for clinical application.

关键词： Tissue engineering     cartilage     bone     tendon     recent advances    

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Analysis of suitable geometrical parameters for designing a tendon-driven under-actuated mechanical finger

Francesco PENTA,Cesare ROSSI,Sergio SAVINO

《机械工程前沿（英文）》 2016年 第11卷 第2期   页码 184-194 doi: 10.1007/s11465-016-0385-y

摘要：

This study aims to optimize the geometrical parameters of an under-actuated mechanical finger by conducting a theoretical analysis of these parameters. The finger is actuated by a flexion tendon and an extension tendon. The considered parameters are the tendon guide positions with respect to the hinges. By applying such an optimization, the correct kinematical and dynamical behavior of the closing cycle of the finger can be obtained. The results of this study are useful for avoiding the snap-through and the single joint hyperflexion, which are the two breakdowns most frequently observed during experimentation on prototypes. Diagrams are established to identify the optimum values for the tendon guides position of a finger with specified dimensions. The findings of this study can serve as guide for future finger design.

关键词： tendon-driven fingers     mechanical finger design     under-actuated mechanical systems    

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Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要：

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词： load distribution     calculation method     pipe threaded connections     tension load    

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Experimental research on the creep behavior and bearing capacity of repeatedly prestressed concrete beam

SHAO Xudong, LI Lifeng, YANG Jianjun

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 305-311 doi: 10.1007/s11709-007-0040-0

摘要： In the prestress tensioning process of medium or short span prestressed concrete beam bridges, there are always many serious problems, such as the camber of straight beam being too large, curved beam going crosswise, and columns of rigid beam bridge cracking, that can be commonly seen because of its greater additional stress in prestressing. To solve the above problems, a new concept of repeatedly prestressed bridge structure was innovatively proposed in this work. It was proved, through theoretical and experimental comparison between this new structure and the traditional prestressed structure, that the application of repeated prestressing technology can greatly improve the mechanical and deformational performance of the low height beam during construction and long-term use. Furthermore, a kind of computational formula to calculate creep strain and deformation due to repeated prestressing in terms of time was derived in this paper and the bearing capacity of this new structure has been tested. Finally, the work concludes that there is a bright application prospect for this new structure for medium and short span prestressed beam bridges to control deformations.

关键词： computational     cracking     technology     prestressed concrete     application prospect    

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Damage identification in connections of moment frames using time domain responses and an optimization

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 851-866 doi: 10.1007/s11709-021-0739-3

摘要： Damage is defined as changes to the material and/or geometric properties of a structural system, comprising changes to the boundary conditions and system connectivity, adversely affecting the system’s performance. Inspecting the elements of structures, particularly critical components, is vital to evaluate the structural lifespan and safety. In this study, an optimization-based method for joint damage identification of moment frames using the time-domain responses is introduced. The beam-to-column connection in a metallic moment frame structure is modeled by a zero-length rotational spring at both ends of the beam element. For each connection, an end-fixity factor is specified, which changes between 0 and 1. Then, the problem of joint damage identification is converted to a standard optimization problem. An objective function is defined using the nodal point accelerations extracted from the damaged structure and an analytical model of the structure in which the nodal accelerations are obtained using the Newmark procedure. The optimization problem is solved by an improved differential evolution algorithm (IDEA) for identifying the location and severity of the damage. To assess the capability of the proposed method, two numerical examples via different damage scenarios are considered. Then, a comparison between the proposed method and the existing damage identification method is provided. The outcomes reveal the high efficiency of the proposed method for finding the severity and location of joint damage considering noise effects.

关键词： damage identification     beam-to-column connection     time-domain response     optimization    

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Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 81-91 doi: 10.1007/s11709-018-0468-4

摘要： Fiber reinforced polymer(FRP) have unique advantages like high strength to weight ratio, excellent corrosion resistance, improving deformability and cost effectiveness. These advantages have gained wide acceptance in civil engineering applications. FRP tendons for prestressing applications are emerging as one of the most promising technologies in the civil engineering industry. However, the behavior of such members under the influence of elevated temperatures is still unknown. The knowledge and application of this could lead to a cost effective and practical considerations in fire safety design. Therefore, this study examines the deflection behavior of the carbon fiber reinforced polymer(CFRP) prestressed concrete beam at elevated temperatures. In this article, an analytical model is developed which integrates the temperature dependent changes of effective modulus of FRP in predicting the deflection behavior of CFRP prestressed concrete beams within the range of practical temperatures. This model is compared with a finite element mode (FEM) of a simply supported concrete beam prestressed with CFRP subjected to practical elevated temperatures. In addition, comparison is also made with an indirect reference to the real behavior of the material. The results of the model correlated reasonably with the finite element model and the real behavior. Finally, a practical application is provided.

关键词： FRP     CFRP     concrete     elevated temperatures     deflections     prestress    

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Calculation method of radial stress and deformation on conic threaded connections with interference fit

Shoujun CHEN, Qiang LI, Qi AN,

《机械工程前沿（英文）》 2010年 第5卷 第3期   页码 302-307 doi: 10.1007/s11465-010-0018-9

摘要： This paper presents a calculation method for radial stress distribution and deformation on conic threaded connections with interference fit. Based on elastic mechanics, a new calculation model is established using the thick-walled-cylindrical theory. A sample calculation for API 88.9 mm conic threaded connection indicates that the method proposed in this paper is reasonable, and the finite element analysis (FEA) method is used to validate the proposed method. The results obtained by the proposed method and FEA method are identical. The model offers a new way of calculating the radial stress and deformation on conic thread connections with interference fit.

关键词： conic threaded connections     interference fit     radial stress     deformation     finite element analysis (FEA)    

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On the seismic stability analysis of reinforced rock slope and optimization of prestressed cables

Wenbo ZHENG, Xiaoying ZHUANG, Yongchang CAI

《结构与土木工程前沿（英文）》 2012年 第6卷 第2期   页码 132-146 doi: 10.1007/s11709-012-0152-z

摘要： The evaluation of the seismic stability of high rock slopes is of vital importance to ensure the safe operation of the hydropower stations. In this paper, an equivalent pseudo-static force analysis based on the finite element method is developed to evaluate the seismic stability of reinforced rock slopes where the prestressed cables are modeled by the bar elements applied with nodal forces and bounded only at the anchored parts. The method is applied to analyze a high rock slope in south-west China and the optimization of cables. The stabilization effects of prestressed cables on the seismic stability of the slope are studied, the simulations of the concrete heading are discussed and the potential failure modes of the shear concrete plug are compared. Based on this, the optimization of cables is studied including the anchor spacing and inclined angles.

关键词： high rock slope     reinforced system     optimization     prestressed cable     seismicity    

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Experimental study on pile-end post-grouting piles for super-large bridge pile foundations

Weiming GONG, Guoliang DAI, Haowen ZHANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 228-233 doi: 10.1007/s11709-009-0019-0

摘要： The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced in this paper. There are totally 21 test piles. The maximum pile diameter varies from 2.5 m to 3 m, and the maximum length is 125 m; the bearing capacity of the post-grouting piles is over ten thousands tons. Based on the test results, the bearing capacity, displacement, and bearing characteristic before and after grouting were analyzed. The results show that the bearing capacity of the piles are increased in different degrees after grouting although the technical parameters, including the patterns of grouting pipes, pressure, dosages of cement, duration of grouting lasting time, are different. However, the obtained values are very discrete. In addition, the calculation formula for the post-grouting piles under specified grouting condition was deduced based on the statistics analysis results of 57 test piles. The research results have been applied in the design of bridge foundation.

关键词： self-balanced testing technique     pile-end post-grouting     bearing capacity     grouting technology    

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State-of-the-art on resistance of bearing-type bolted connections in high strength steel

Guoqiang LI, Yifan LYU, Yanbo WANG

《结构与土木工程前沿（英文）》 2020年 第14卷 第3期   页码 569-585 doi: 10.1007/s11709-020-0607-6

摘要： With the recent development of material science, high strength steel (HSS) has become a practical solution for landmark buildings and major projects. The current codes for design of bearing-type bolted connections of steel constructions were established based on the research of conventional steels. Since the mechanical properties of HSS are different from those of conventional steels, more works should be done to develop the appropriate approach for the design of bearing-type bolted connections in HSS. A review of the research carried out on bearing-type bolted connections fabricated from conventional steel and HSS is presented. The up-to-date tests conducted at Tongji University on four connection types fabricated from three grades of HSS with nominal yield strengths of 550, 690, and 890 MPa are presented. The previous research on failure modes, bearing resistance and the design with consideration of bolt hole elongation are summarized. It is found that the behavior of bolted connections in HSS have no drastic difference compared to that of conventional steel connections. Although the ductility is reduced, plastic deformation capacity of HSS is sufficient to ensure the load redistribution between different bolts with normal construction tolerances. It is also found that behavior of each bolt of multi-bolt connections arranged in perpendicular to load direction is almost identical to that of a single-bolt connection with the same end distance. For connections with bolts arranged in parallel to load direction, the deformation capacity of the whole connection depends on the minimum value between the end distance and the spacing distances in load direction. The comparison with existing design codes shows that Eurocode3 and Chinese GB50017-2017 are conservative for the design of bolted connections in HSS while AISC 360-16 may overestimate the bearing resistance of bolted connections.

关键词： High strength steel     bolted connection     bearing behavior     design codes    

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Seismic retrofitting of severely damaged RC connections made with recycled concrete using CFRP sheets

Yasmin MURAD, Wassel AL BODOUR, Ahmed ASHTEYAT

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 554-568 doi: 10.1007/s11709-020-0613-8

摘要： An experimental and numerical program is carried out in this research to investigate the influence of CFRP sheets on the cyclic behavior of unconfined connections made with recycled concrete. Cement is partially replaced by silica fume, iron filling and pulverised fuel ash using two different percentages: 15% and 20%. Each specimen is partially loaded at the first stage and then specimens are repaired using CFRP sheets. The repaired specimens are then laterally loaded until failure. In addition, a finite element model is built in ABAQUS and verified using the experimental results. The experimental results have shown that the repaired specimens have regained almost double the capacity of the un-repaired specimens and hence the adopted repair configuration is recommended for retrofitting seismically vulnerable RC connections. Increasing cement replacement percentage by silica fume, fuel ash or iron filling from 15% to 20% has reduced joint carrying capacity and weakened the joint. It is recommended using 15% pulverised fuel ash or silica fume as cement partial replacement to enhance the strength and ultimate drift of beam-column joints under cyclic loading. Iron filling concrete is also recommended but the enhancement is relatively less than that found with pulverised fuel ash concrete and silica fume concrete.

关键词： retrofitting     CFRP sheets     recycled concrete     pulverised fuel ash     silica fume     cyclic     beam-column connections    

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标题 作者 时间 类型 操作

Seismic performance of fabricated continuous girder bridge with grouting sleeve-prestressed tendon compositeconnections

期刊论文

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

期刊论文

Nonlinear experimental response of non-conventional composite steel and concrete connection

Tobia ZORDAN, Bruno BRISEGHELLA

期刊论文

Function-oriented optimization design method for underactuated tendon-driven humanoid prosthetic hand

期刊论文

Tissue engineering of cartilage, tendon and bone

null

期刊论文

Analysis of suitable geometrical parameters for designing a tendon-driven under-actuated mechanical finger

Francesco PENTA,Cesare ROSSI,Sergio SAVINO

期刊论文

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

期刊论文

Experimental research on the creep behavior and bearing capacity of repeatedly prestressed concrete beam

SHAO Xudong, LI Lifeng, YANG Jianjun

期刊论文

Damage identification in connections of moment frames using time domain responses and an optimization

期刊论文

Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

期刊论文

Calculation method of radial stress and deformation on conic threaded connections with interference fit

Shoujun CHEN, Qiang LI, Qi AN,

期刊论文

On the seismic stability analysis of reinforced rock slope and optimization of prestressed cables

Wenbo ZHENG, Xiaoying ZHUANG, Yongchang CAI

期刊论文

Experimental study on pile-end post-grouting piles for super-large bridge pile foundations

Weiming GONG, Guoliang DAI, Haowen ZHANG

期刊论文

State-of-the-art on resistance of bearing-type bolted connections in high strength steel

Guoqiang LI, Yifan LYU, Yanbo WANG

期刊论文

Seismic retrofitting of severely damaged RC connections made with recycled concrete using CFRP sheets

Yasmin MURAD, Wassel AL BODOUR, Ahmed ASHTEYAT

期刊论文