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Engineering structures
Butterworth Scientific Ltd.
Engineering structures

Butterworth Scientific Ltd.

月刊

0141-0296

Engineering structures/Journal Engineering structuresSCI
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    Bond-slip law for the analysis of ribbed steel-FRP composite bars embedded into FRP-confined concrete

    Wang, MifengWang, YanleiChen, Guipeng
    1.1-1.16页
    查看更多>>摘要：Bond behaviour of composite bars whose steel core is enveloped by a ribbed FRP layer is investigated when the bars are placed inside a concrete member uniformly confined by outer FRP wrappings. The test results show that passive confinement - by resisting concrete transverse dilation induced by bar slip - brings in a change in bond failure mode, from splitting to pull-out (both failure modes being controlled by concrete), and even to bar damage (failure mode controlled by the reinforcement). Furthermore, moderate levels of FRP confinement stiffness (0.56 - 0.85 GPa) are advantageous for both bond ductility and strength, while high confinement levels may lead to a brittle bond behaviour. Existing bond-slip laws are examined with the focus on their limitations when they are used to model the effect of FRP confinement on bond. A refined 3D rib-scale FE model is developed to accurately describe bond static and kinematic behaviour at the local level in the case of ribbed composite bars embedded into a concrete member uniformly confined via FRP wrappings. To optimize bond performance, a regular bond-slip law is formulated for ribbed composite bars, taking into account such parameters as concrete strength, cover-to-bar diameter ratio, bar-rib spacing, and the level of confinement.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Theoretical analysis and design method of CFRP-strengthened inclined welded steel plates with initial cracks under fatigue loadings

    Hu, LiliDing, XinyuLi, LingzhenChen, Man-Tai...
    1.1-1.17页
    查看更多>>摘要：CFRP strengthening can effectively enhance fatigue lives of welded steel structures. However, due to the complex multi-axial stress states at the welds and cracks, an effective fatigue life estimation and a strengthening designing method are yet established. Based on fatigue tests and associated finite element simulations from the current research group, a fatigue life calculation model and a design method for CFRP-strengthened inclined welded steel plates with initial cracks were proposed. Firstly, a residual stress distribution model along the critical paths of the inclined weld steel plate was established, considering the effects of weld angle, weld reinforcement, and weld width. The distribution of residual stress, which exhibits a quadratic shape, closely aligns with that in numerical models. Secondly, an analytical model, which is suitable for engineering design, was established to estimate the stress intensity at the welds and cracks of the CFRP strengthened steel plates in the initial and crack propagation states. It involves the influences of weld reinforcement, CFRP strengthening, residual stress, and crack mode mixity. Furthermore, based on the NASGRO model, a fatigue life estimation program was established. Thirdly, a parametric study was conducted to quantify the influences of key parameters, including weld geometry, initial damage, loading condition, and CFRP stiffness. Finally, a strengthening design method was proposed, and design examples were given, providing a valuable reference for engineering practice.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Evolutionary characteristics of vortex drift patterns around a central-slotted box girder during torsional vortex-induced vibration and its physical mechanism

    Hu, ChuanxinChen, ShuaikuangZhao, LinWang, Xianglong...
    1.1-1.15页
    查看更多>>摘要：Despite the widespread application of central-slotted box girders in engineering, their exceptional resistance to flutter instability has highlighted the need for further improvements to mitigate vortex-induced vibrations (VIVs). To investigate the VIV mechanism in a typical central-slotted box girder, synchronous pressure and displacement measurements were conducted using spring-suspended sectional model (SSSM) tests in a wind tunnel. Spatial distribution of aerodynamic forces on the girder were analyzed in the Simplified Vortex Model (SVM) framework, highlighting the physical relationship between the spatiotemporal evolution of aerodynamic forces and their associated key flow field for girder undergoing VIV. The spatiotemporal distribution of aerodynamic forces on the girder and the corresponding critical vortex drift patterns were analyzed at various stages of the VIV-development process, including the VIV-beginning, ascent stage, extreme amplitude, descent stage, and VIV-ending. Wind tunnel test results indicated that torsional VIV occurred when the maintenance rails were installed on the lower surface of the girder at an + 3 degrees angle of attack, whereas no VIV was observed without rails. Separated vortex formed at the tail of the maintenance rail and drifted on the web plate at VIV-beginning point which excited torsional VIV and eventually subsided at VIV-ending point. The above results demonstrated that maintenance rails played a pivotal role in inducing VIV phenomena. The synergy between vortices drifting on the lower surface of the upstream girder and both surfaces of the downstream girder amplifies vibrations, contributing positively to VIVs and correlating with the VIV amplitude. Conversely, the vortex drifting on the web plate of the downstream girder partially counteracts the effects of vortices drifting in aforementioned zones, potentially contributing to the self-limiting nature of the VIV amplitudes. The vortex synergistic effect was proposed to comprehensively analyze the action mechanism of vortices in different zones, offering insights for future designs and mitigation strategies.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Development of earthquake-resilient precast concrete beam-to-column connections with bottom replaceable buckling-restrained brace dampers

    Chen, HuimingBai, JiulinLiu, Jiacheng
    1.1-1.18页
    查看更多>>摘要：The strong column-weak beam yield mechanism is commended in current seismic design codes for reinforced concrete frames. However, the plastic deformations of concrete and reinforcements in the plastic hinge zone pose quite a challenge to the structural post-earthquake repair. To overcome this deficiency, a novel earthquakeresilient precast beam-to-column connection with bottom replaceable miniature buckling-restrained braces (MBRBs) is proposed in this study. The mechanical hinge is adopted at the top of the beam as the rotational center, while the MBRBs are placed at the beam bottom to dissipate the seismic energy under strong earthquakes. The mechanical model and seismic design procedure of the resilient connection are developed. Three full-scale beam-to-column connections with different configurations are introduced and designed. Quasi-static cyclic loading tests were conducted to gain insights into the seismic performance and post-repair behavior of the connections. Test results demonstrated that the connections with welded MBRBs exhibited excellent hysteretic behaviors even at the 4 % inter-story drift ratio. As expected in design, the damage was concentrated at the MBRBs, and the functionality of the connection can be recovered rapidly by replacing the damaged MBRBs. A numerical approach based on the birth-death element technology is developed to model the repaired connection. The numerical results showed the finite element model can effectively capture the pre- and post-repair seismic performance of the beam-to-column connection.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    The crashworthiness of hierarchical sandwich circular tubes

    Gao, ZhipengLi, JiahuiXia, FukunRuan, Dong...
    1.1-1.16页
    查看更多>>摘要：Sandwich tubes have been extensively investigated; however, there are limited studies on the hierarchical sandwich tubes. Inspired by the hierarchy configuration and sandwich column, innovative hierarchical sandwich circular (HSC) tubes were developed with the aim of improving the crashworthiness of sandwich tubes. The compressive characteristics of HSC tubes with various wall thicknesses, hierarchical orders and number of ribs (such as four, six and eight ribs for HSC-R4, HSC-R6 and HSC-R8) were numerically investigated. The SEA of HSC-R4, HSC-R6 and HSC-R8 tubes rises with hierarchical order, wall thickness and number of rib. Compared with a hollow circular tube, the SEA of HSC-R8-3 tube increases by more than 1.6 times. Moreover, HSC tubes with thicker inner cores display better compressive performance. In addition, the theory model is able to well estimate the mean crushing force of HSC-R4.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Influence of ultrasonic impact treatment on fatigue performance of novel double-sided full penetration U-rib welded joints

    Zheng, HaoJie, ZhiyuLu, WeiZhang, Lexin...
    1.1-1.20页
    查看更多>>摘要：Ultrasonic Impact Treatment (UIT) is a well-established post-weld treatment technique known for enhancing fatigue resistance of welded joints by reducing stress concentrations and welding residual stresses (WRS). However, its effect on fatigue performance of novel double-sided full penetration U-rib welded joints in orthotropic steel decks remains inadequately explored. In this study, UIT and fatigue tests were conducted on singleand double-sided full penetration U-rib joints with varying deck thicknesses. Finite element modeling was employed to simulate the welding and UIT processes, enabling the calculation of the amplitude and distribution of WRS. Subsequently, the FRANC3D and ABAQUS software were coupled to integrate WRS with cyclic loading for crack propagation and fatigue life assessment. The results reveal that UIT significantly reduces residual tensile stresses, with a more pronounced reduction in longitudinal residual stresses compared to transverse ones. UIT changes the location of crack initiation in U-rib welded joints, causing the crack initiation position to shift from the outer weld toe to the inner weld toe or root. Numerical results of crack propagation path and fatigue life align closely with experimental results, validating the reliability of the numerical model. Furthermore, UIT markedly extends the fatigue life of U-rib welded joints, with fatigue life improvements ranging from 1.5 to 2.6 times for double-sided full penetration U-rib joints and from 11.0 to 14.0 times for single-sided U-rib joints.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Experimental study on high-strength steel earthquake resilient beam-column joints with double damage elements

    Zheng, DongdongGuo, HongchaoLi, HaoLiang, Gang...
    1.1-1.20页
    查看更多>>摘要：Aiming to address the existing issues of earthquake resilient beam-column joints, this paper proposes a high-strength steel earthquake resilient beam-column joint with double damage elements. The relationship between the load-carrying capacity and energy dissipation ratio of the double damage elements is investigated, and the post-seismic recoverable performance of the joint is verified through damage element replacement experiment. The results indicate that the flange cover plate supports 66 %-78 % of the joint load, while the damper supports 22 %-34 %. Through the experimental analysis, it is found that the energy consumption of double damage elements accounts for more than 95 % of the total energy consumption of the joint. Combined with the finite element ALLPD, it is found that the energy consumption of the flange cover plate accounts for 85 % of the total energy consumption of the double damage elements, and the damper accounts for 15 %, which fully explains that the double damage elements can synergistically bear load-dissipate the energy. A comparison of the joint hysteresis curves before and after the replacement of the damaged element shows that the two curves overlap almost completely. Additionally, the residual deformations for the three types of joints fall within the DS2 range specified by FEMA P-58. This indicates that the joints discussed in this paper exhibit excellent post-earthquake recovery performance. The proposed cross-section stress ratio beta can accurately reflect the phenomenon of sequential yielding between double damage elements. Based on the parameter beta, a simplified calculation method of joint yielding capacity is proposed. By comparing the theoretically calculated values with the experimental and finite element results, it is found that the maximum error is not more than 10 %, which proves the effectiveness of the joint yielding load capacity calculation method.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Intelligent zoning design of concrete-faced rockfill dams using image-parameter fusion enhanced generative adversarial networks

    Liao, WenjieZhang, ZongliangLiu, BiaoLu, Xinzheng...
    1.1-1.14页
    查看更多>>摘要：The design of concrete-face rockfill dams (CFRDs) is gradually evolving from digitization to intelligent design, primarily driven by advanced technologies such as generative artificial intelligence (AI). Generative AI offers powerful capabilities for extracting and mining data features and generating new design solutions efficiently through inference. These strengths provide critical technical support for intelligent CFRD design, facilitating the full utilization of design data, and significantly improving design efficiency and quality. However, CFRD design is a highly specialized and complex task, and conventional generative AI techniques often fail to produce professional-grade designs. In response to this challenge, this study explored generative intelligent design methods specifically for the critical task of CFRD profile design. An intelligent design method based on featurefusion generative adversarial networks (GANs) for CFRD profile solutions is proposed. This approach enables the dense representation and augmentation of design data, GAN model training, and automated evaluation, thereby addressing the key challenge of fusing small-sample multimodal image-parameter data. The effectiveness of the intelligent design method for CFRD profiles was validated through algorithm analysis and case studies. The design efficiency was nearly 10 times higher than that of traditional engineer-driven designs, reducing the time required from 1-2 h to approximately 6 min. The proposed intelligent design approach has great potential and provides valuable insights for the further development of intelligent design of rockfill dams.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Evaluation of the flexural capacity of RC slabs strengthened with combined EBROG-EBR prestressed CFRP strips and an innovative composite anchorage system

    Breveglieri, MatteoMartinelli, EnzoMoshiri, NiloufarCzaderski, Christoph...
    1.1-1.17页
    查看更多>>摘要：The Externally Bonded Reinforcement on Groove (EBROG) is an innovative technique for strengthening concrete structures using CFRP strips, that has enabled the development of a fully composite solution for prestressed strips. This study presents the results of a large-scale experimental campaign on six reinforced concrete slab strips, each 6 m long, tested using a six-point bending setup and strengthened with both non-prestressed and prestressed, EBR and EBROG techniques. The research aimed to validate the effectiveness and reliability of the EBROG technique coupled with a recently developed anchorage system and to investigate the performance of a novel strengthening approach that combines both EBR and EBROG techniques. In this latter solution, the EBROG technique is applied in the anchorage zones, while the EBR technique is used over the remaining slab length. The approach was considered to simplify the application process without compromising the effectiveness of the strengthening. The test results showed that the EBROG solution can increase load carrying capacity by more than 32 % compared to a non-prestressed EBR solution. By combining EBROG and EBR, similar loading behaviour was observed, demonstrating that it is a valid alternative for slabs and beams where intermediate debonding is not the dominant failure mode. The experimental results are supported by the numerical study, which, through the simulation of interface slips between the FRP and the concrete substrate, allows for an accurate understanding of the load transfer mechanism between concrete and CFRP in the different strengthened systems.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Failure behavior of single-/double-shear in composite honeycomb sandwich panels based on acoustic emission

    Dong, FanKong, WeihongLi, YazhiYang, Xiao...
    1.1-1.18页
    查看更多>>摘要：Composite honeycomb sandwich panels are extensively used for their high strength-to-weight ratio, yet their damage mechanisms under out-of-plane shear loading remain poorly understood. In this work, out-of-plane shearing static and fatigue tests were performed on three types of composite honeycomb sandwich panel specimens, two for single shear and one for double shear. Real-time acoustic emission (AE) monitoring was employed, and the AE signals were decomposed to extract detailed damage information. The ranges of the AE parameter values corresponding to core shear microcracking and crack propagation were deduced. Entropy was introduced as a new quantitative metric to reflect the damage progression within the cores, with its trajectory effectively depicting the evolution of core damage over increasing fatigue cycles. Andrews plots were used as a form of phase space reconstruction to visualize AE data related to damage in composite honeycomb sandwich panels, enabling clear differentiation between early-stage shear microcracking and later-stage crack propagation through distinct curve patterns. The integration of entropy and Andrews plots provides a new approach to understanding damage mechanisms in composite honeycomb sandwich panels under out-of-plane shear loading.
      原文链接:
    • NETL
    • NSTL
    • Elsevier