Pub Date : 2024-07-27DOI: 10.1177/13694332241267901
Mohammed Elhassan Omer Elhassan, Le-Dong Zhu, Wael Alhaddad, Zhongxu Tan
Studies on aerodynamic controls of central-slotted box decks primarily focused on mitigating vortex-induced vibrations (VIV), as this type of deck typically performs well against flutter instability. However, as the span length increases, the critical wind speed of aerodynamic static instability ( U cr) might be lower than flutter critical wind speed. Thus, U cr will determine the overall aerodynamic performance of such bridges. Investigating this instability through wind tunnel testing methods and numerical simulation can be expensive and time-consuming. In this paper, surrogate models using machine learning approaches, specifically artificial neural network (ANN) and extreme gradient boosting (XGBoost), were developed and optimized for fast and reliable prediction for U cr based on wind tunnel tests and simulation data. The results demonstrated that the built surrogate models can predict U cr accurately. The parametric study results showed that the height ratio of wind fairing apex ( a/b), wind angle of attack ( α), and length of the main span ( L) have the most influence on the U cr compared with other parameters. Finally, based on the developed ANN surrogate model and the artificial bee colony (ABC) optimization algorithm, an optimized section was proposed to enhance the section’s performance against aerodynamic static instability.
对中央开槽箱形桥面气动控制的研究主要集中在减轻涡流诱发振动（VIV）上，因为这种桥面通常对飘动不稳定性表现良好。然而，随着跨度的增加，气动静力不稳定性的临界风速（U cr）可能会低于扑翼临界风速。因此，U cr 将决定此类桥梁的整体空气动力性能。通过风洞试验方法和数值模拟来研究这种不稳定性既昂贵又耗时。本文利用机器学习方法，特别是人工神经网络（ANN）和极梯度提升（XGBoost），开发并优化了代用模型，以便根据风洞试验和模拟数据快速、可靠地预测 U cr。结果表明，建立的代用模型可以准确预测 U cr。参数研究结果表明，与其他参数相比，整流罩顶点高度比（a/b）、风攻角（α）和主跨长度（L）对 U cr 的影响最大。最后，基于所建立的 ANN 代理模型和人工蜂群（ABC）优化算法，提出了一种优化截面，以提高截面的气动静力失稳性能。
{"title":"Surrogate modeling for aerodynamic static instability of central-slotted box decks using machine learning approaches","authors":"Mohammed Elhassan Omer Elhassan, Le-Dong Zhu, Wael Alhaddad, Zhongxu Tan","doi":"10.1177/13694332241267901","DOIUrl":"https://doi.org/10.1177/13694332241267901","url":null,"abstract":"Studies on aerodynamic controls of central-slotted box decks primarily focused on mitigating vortex-induced vibrations (VIV), as this type of deck typically performs well against flutter instability. However, as the span length increases, the critical wind speed of aerodynamic static instability ( U cr) might be lower than flutter critical wind speed. Thus, U cr will determine the overall aerodynamic performance of such bridges. Investigating this instability through wind tunnel testing methods and numerical simulation can be expensive and time-consuming. In this paper, surrogate models using machine learning approaches, specifically artificial neural network (ANN) and extreme gradient boosting (XGBoost), were developed and optimized for fast and reliable prediction for U cr based on wind tunnel tests and simulation data. The results demonstrated that the built surrogate models can predict U cr accurately. The parametric study results showed that the height ratio of wind fairing apex ( a/b), wind angle of attack ( α), and length of the main span ( L) have the most influence on the U cr compared with other parameters. Finally, based on the developed ANN surrogate model and the artificial bee colony (ABC) optimization algorithm, an optimized section was proposed to enhance the section’s performance against aerodynamic static instability.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141798141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-14DOI: 10.1177/13694332241260131
Ying-Shyang Shan, Yongzhi Gong, Yi Wang
This study proposed an innovative step-shaped composite (SSC) slab system that has a high assembly rate. Experimental and analytical studies were carried out to investigate the flexural behavior of wet joints connecting SSC slabs and H-shaped steel beams under negative moment. The effects of three factors were experimentally examined, including width of the horizontal laminated interface, seated length of precast slabs on steel beam, and type of wet joint materials. The crack development, load–deflection response and strain distribution were monitored during the loading. As found, the SSC slabs showed similar flexural behavior to that of the slab cast-in-situ. The seated length (10-30 mm) had a negligible effect on the flexural behavior of the SSC slabs, while the beneficial effect of using ultra-high performance concrete (UHPC) as the wet joint material was significant. Besides, using a wider horizontal laminated interface, initial cracking load and yield load could be significantly improved, though it had a marginal effect on the bearing capacity. Based on the collected bond test results, a cracking load model for SSC slabs with UHPC wet joint was proposed and validated. Finally, a refined finite element (FE) model was established and calibrated against the test results for parametric analysis.
{"title":"Flexural behavior of wet joints connecting step-shaped composite slab and steel beam under negative moment","authors":"Ying-Shyang Shan, Yongzhi Gong, Yi Wang","doi":"10.1177/13694332241260131","DOIUrl":"https://doi.org/10.1177/13694332241260131","url":null,"abstract":"This study proposed an innovative step-shaped composite (SSC) slab system that has a high assembly rate. Experimental and analytical studies were carried out to investigate the flexural behavior of wet joints connecting SSC slabs and H-shaped steel beams under negative moment. The effects of three factors were experimentally examined, including width of the horizontal laminated interface, seated length of precast slabs on steel beam, and type of wet joint materials. The crack development, load–deflection response and strain distribution were monitored during the loading. As found, the SSC slabs showed similar flexural behavior to that of the slab cast-in-situ. The seated length (10-30 mm) had a negligible effect on the flexural behavior of the SSC slabs, while the beneficial effect of using ultra-high performance concrete (UHPC) as the wet joint material was significant. Besides, using a wider horizontal laminated interface, initial cracking load and yield load could be significantly improved, though it had a marginal effect on the bearing capacity. Based on the collected bond test results, a cracking load model for SSC slabs with UHPC wet joint was proposed and validated. Finally, a refined finite element (FE) model was established and calibrated against the test results for parametric analysis.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"5 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141343283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-14DOI: 10.1177/13694332241260135
Shui Liu, Xin Wang, L. Ding, Bin Zhong, Huang Huang, Zhishen Wu
Flexural hybrid reinforced concrete members with fiber reinforced polymer (FRP) and steel bars (hybrid-RC) exhibit significant post-yielding stiffness due to the contribution of tensile FRP bars. To predict the post-yielding deflection of hybrid-RC members, the Bischoff’s model for effective moment of inertia is extended into the post-yielding stage. Based on this extended model, expressions for equivalent moment of inertia, which consider the variation in stiffness along the member span with and without tension stiffening, are proposed. Obtaining close-formed solutions for the yielding moment of hybrid-RC cross sections, a critical parameter for determining the post-yielding effective moment of inertia, proves challenging due to the unknown state of compressive concrete. Therefore, a simplified equation to determine the yielding moment are proposed by regression of data derived from numerical sectional analyses. An experimental database including 92 hybrid-RC beams collected from published literature is established. The performance of the proposed equation for the yielding moment and expressions for the equivalent moment of inertia are evaluated using the database. The results indicate that the proposed equation can effectively predict the yielding moments of hybrid-RC beams. Furthermore, using a constant effective moment for predicting the post-yielding deflection is effective for the specimens with relatively high reinforcement ratios. The benefit of considering the stiffness variation along the member span is evident when dealing with lightly-reinforced concrete members.
{"title":"Post-yielding deflection calculation of flexural hybrid reinforced concrete with a combination of fiber reinforced polymer and steel bars","authors":"Shui Liu, Xin Wang, L. Ding, Bin Zhong, Huang Huang, Zhishen Wu","doi":"10.1177/13694332241260135","DOIUrl":"https://doi.org/10.1177/13694332241260135","url":null,"abstract":"Flexural hybrid reinforced concrete members with fiber reinforced polymer (FRP) and steel bars (hybrid-RC) exhibit significant post-yielding stiffness due to the contribution of tensile FRP bars. To predict the post-yielding deflection of hybrid-RC members, the Bischoff’s model for effective moment of inertia is extended into the post-yielding stage. Based on this extended model, expressions for equivalent moment of inertia, which consider the variation in stiffness along the member span with and without tension stiffening, are proposed. Obtaining close-formed solutions for the yielding moment of hybrid-RC cross sections, a critical parameter for determining the post-yielding effective moment of inertia, proves challenging due to the unknown state of compressive concrete. Therefore, a simplified equation to determine the yielding moment are proposed by regression of data derived from numerical sectional analyses. An experimental database including 92 hybrid-RC beams collected from published literature is established. The performance of the proposed equation for the yielding moment and expressions for the equivalent moment of inertia are evaluated using the database. The results indicate that the proposed equation can effectively predict the yielding moments of hybrid-RC beams. Furthermore, using a constant effective moment for predicting the post-yielding deflection is effective for the specimens with relatively high reinforcement ratios. The benefit of considering the stiffness variation along the member span is evident when dealing with lightly-reinforced concrete members.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"20 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141341574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-14DOI: 10.1177/13694332241260130
Duo Liu, Jin Wu, Xudong Chen, Ye Tian, Jiandong Zhang
The application of segmental precast assembled concrete cover beams in bridge construction is beneficial to promote low carbon, green and sustainable development of construction projects. To investigate the influence of the fabrication process of large key tooth joints on the shear performance of precast assembled concrete cover girders, the damage process of large key tooth assembled prestressed concrete cover girder specimens was investigated by using ABAQUS finite element analysis (FEA). The results show that: the section precast assembled concrete beams under four-point bending loading conditions, it is in the key tooth joint area that obvious cracking occurs; the finite element model of the large key tooth assembled prestressed cover beams can be effectively used to simulate the overall stress behavior of the beams; as the key tooth depth-to-height ratio increases, the stronger the connecting effect between the damaging key tooth and the positive key tooth is, and the load carrying capacity of the assembled beams is increased by 20% compared with the single key tooth, and ductility is increased by 30%; in the range of suitable reinforcement, the change of reinforcement rate does not have a significant effect on the stress performance of the beam.
{"title":"Experimental study and numerical analysis of the flexural performance of key-tooth assembled prestressed concrete cap beam","authors":"Duo Liu, Jin Wu, Xudong Chen, Ye Tian, Jiandong Zhang","doi":"10.1177/13694332241260130","DOIUrl":"https://doi.org/10.1177/13694332241260130","url":null,"abstract":"The application of segmental precast assembled concrete cover beams in bridge construction is beneficial to promote low carbon, green and sustainable development of construction projects. To investigate the influence of the fabrication process of large key tooth joints on the shear performance of precast assembled concrete cover girders, the damage process of large key tooth assembled prestressed concrete cover girder specimens was investigated by using ABAQUS finite element analysis (FEA). The results show that: the section precast assembled concrete beams under four-point bending loading conditions, it is in the key tooth joint area that obvious cracking occurs; the finite element model of the large key tooth assembled prestressed cover beams can be effectively used to simulate the overall stress behavior of the beams; as the key tooth depth-to-height ratio increases, the stronger the connecting effect between the damaging key tooth and the positive key tooth is, and the load carrying capacity of the assembled beams is increased by 20% compared with the single key tooth, and ductility is increased by 30%; in the range of suitable reinforcement, the change of reinforcement rate does not have a significant effect on the stress performance of the beam.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"16 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141343088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-13DOI: 10.1177/13694332241260136
Shitong Hou, Weihao Sun, Tao Wu, Guangdong Liu, Xiao Fan, Jian Zhang, Zhishen Wu, Gang Wu
The girder bottom inspection is becoming an important part of the bridge maintenance process. In this study, a vehicular defect identification system was built to make the inspection process of bridge bottoms more intelligent, efficient and accurate. The system contains three main parts: image acquisition, image stitching and defect recognition. The image acquisition part was responsible for controlling the start and stop of image acquisition, data transmission and image storage. The image sequences collected were processed and stitched into a panoramic image during the image stitching process, and the coordinate systems of images would also be unified. Finally, the defects in the image were recognized and positioned. Combined with the BIM model, multiscale digital display of bridge bottom defect, including defect recognition and positioning results, was obtained. With the multiscale information, the maintenance for bridges will become more convenient. The deep learning model U2-Net was used to detect cracks and realized a defect detection accuracy of millimeter-level. The experimental results proved that the cracks in the images of the bridge bottom could be detected effectively using the proposed method with a high performance of 79.15 % test dataset F1-score and 0.691 MIoU. Additionally, the proposed defect location method had a centimeter-level defect location accuracy.
{"title":"Study on a vehicular defect identification system for girder bottom inspection of bridges","authors":"Shitong Hou, Weihao Sun, Tao Wu, Guangdong Liu, Xiao Fan, Jian Zhang, Zhishen Wu, Gang Wu","doi":"10.1177/13694332241260136","DOIUrl":"https://doi.org/10.1177/13694332241260136","url":null,"abstract":"The girder bottom inspection is becoming an important part of the bridge maintenance process. In this study, a vehicular defect identification system was built to make the inspection process of bridge bottoms more intelligent, efficient and accurate. The system contains three main parts: image acquisition, image stitching and defect recognition. The image acquisition part was responsible for controlling the start and stop of image acquisition, data transmission and image storage. The image sequences collected were processed and stitched into a panoramic image during the image stitching process, and the coordinate systems of images would also be unified. Finally, the defects in the image were recognized and positioned. Combined with the BIM model, multiscale digital display of bridge bottom defect, including defect recognition and positioning results, was obtained. With the multiscale information, the maintenance for bridges will become more convenient. The deep learning model U2-Net was used to detect cracks and realized a defect detection accuracy of millimeter-level. The experimental results proved that the cracks in the images of the bridge bottom could be detected effectively using the proposed method with a high performance of 79.15 % test dataset F1-score and 0.691 MIoU. Additionally, the proposed defect location method had a centimeter-level defect location accuracy.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"32 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141347980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-13DOI: 10.1177/13694332241260868
Shu-Meng Li, You-Lin Xu, Shang-Jun Jiang
For long span bridges located in coastal areas, a limited number of anemometers are often installed on the bridge to monitor wind conditions and wind effects. To make best use of wind information from limited anemometers, this paper proposes a wind field reconstruction method, based on wind conditional simulation method with the iteration of coherence function along the bridge deck, for providing a complete wind field for the bridge. In terms of wind field reconstruction method, this paper further investigates the optimal anemometer placement for obtaining the best wind field reconstruction with the least number of anemometers. The proposed two methods are finally applied to a real long suspension bridge equipped with three anemometers on one side of the bridge to demonstrate the feasibility and accuracy of the methods. The results show that the reconstructed wind field not only matches with the measured wind speed histories and spectrums but also provides the best wind coherence function, wind speed histories, and wind spectrums for the entire bridge deck. The results also show that with the limited number of anemometers installed at appropriate positions relative to the bridge deck, the wind field can be reconstructed satisfactorily.
{"title":"Wind field reconstruction and optimal anemometer placement for long span bridges","authors":"Shu-Meng Li, You-Lin Xu, Shang-Jun Jiang","doi":"10.1177/13694332241260868","DOIUrl":"https://doi.org/10.1177/13694332241260868","url":null,"abstract":"For long span bridges located in coastal areas, a limited number of anemometers are often installed on the bridge to monitor wind conditions and wind effects. To make best use of wind information from limited anemometers, this paper proposes a wind field reconstruction method, based on wind conditional simulation method with the iteration of coherence function along the bridge deck, for providing a complete wind field for the bridge. In terms of wind field reconstruction method, this paper further investigates the optimal anemometer placement for obtaining the best wind field reconstruction with the least number of anemometers. The proposed two methods are finally applied to a real long suspension bridge equipped with three anemometers on one side of the bridge to demonstrate the feasibility and accuracy of the methods. The results show that the reconstructed wind field not only matches with the measured wind speed histories and spectrums but also provides the best wind coherence function, wind speed histories, and wind spectrums for the entire bridge deck. The results also show that with the limited number of anemometers installed at appropriate positions relative to the bridge deck, the wind field can be reconstructed satisfactorily.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"12 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141346664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-12DOI: 10.1177/13694332241260867
Xiaoqing Zhou, Qianmei Lu, Jiafan Tang, Xianfeng Wang
Microcapsule-based self-healing concrete (MSC) has been widely studied, with a focus on static behavior and self-healing effectiveness. However, the dynamic mechanical properties of MSC have rarely been studied. This study presents a mesoscale numerical investigation of the dynamic compressive behavior of MSC under impact loading. In mesoscale, MSC is regarded as a four-phase composite material mainly composed of coarse aggregates, interface transition zones, cement mortar, and microcapsules. A pseudo 3D numerical model is constructed by combining a slice of a detailed mesoscale model with a homogenous 3D model. The mesoscale MSC slice models with different mass fractions of microcapsules (0%, 2%, 5%, and 8%) are constructed. Different coarse aggregate shapes (i.e., circles, ellipses, and polygons) are considered. The uniaxial dynamic compressive behaviors of MSC materials under loads of different strain rates are numerically simulated and compared with those from split Hopkinson pressure bar tests previously done by the authors. The comparison results show that the present mesoscale model can accurately predict the compressive strength and failure mode of MSC. The effects of the microcapsules ratio and strain rate on the dynamic strength are studied. Results show that the MSC compressive strength decreases with the increase in microcapsules and increases with the increase in strain rate. The dynamic increase factor (DIF) of the specimen is jointly contributed by the material DIF, inertial constraints, and heterogeneity. Different aggregate shapes have little effect on the simulation results of MSC behavior. The obtained dynamic mechanical properties of MSC may assist in designing MSC to resist collisions or explosions.
{"title":"Mesoscale modeling of dynamic compressive behavior of microcapsule-based self-healing concrete under impact loading","authors":"Xiaoqing Zhou, Qianmei Lu, Jiafan Tang, Xianfeng Wang","doi":"10.1177/13694332241260867","DOIUrl":"https://doi.org/10.1177/13694332241260867","url":null,"abstract":"Microcapsule-based self-healing concrete (MSC) has been widely studied, with a focus on static behavior and self-healing effectiveness. However, the dynamic mechanical properties of MSC have rarely been studied. This study presents a mesoscale numerical investigation of the dynamic compressive behavior of MSC under impact loading. In mesoscale, MSC is regarded as a four-phase composite material mainly composed of coarse aggregates, interface transition zones, cement mortar, and microcapsules. A pseudo 3D numerical model is constructed by combining a slice of a detailed mesoscale model with a homogenous 3D model. The mesoscale MSC slice models with different mass fractions of microcapsules (0%, 2%, 5%, and 8%) are constructed. Different coarse aggregate shapes (i.e., circles, ellipses, and polygons) are considered. The uniaxial dynamic compressive behaviors of MSC materials under loads of different strain rates are numerically simulated and compared with those from split Hopkinson pressure bar tests previously done by the authors. The comparison results show that the present mesoscale model can accurately predict the compressive strength and failure mode of MSC. The effects of the microcapsules ratio and strain rate on the dynamic strength are studied. Results show that the MSC compressive strength decreases with the increase in microcapsules and increases with the increase in strain rate. The dynamic increase factor (DIF) of the specimen is jointly contributed by the material DIF, inertial constraints, and heterogeneity. Different aggregate shapes have little effect on the simulation results of MSC behavior. The obtained dynamic mechanical properties of MSC may assist in designing MSC to resist collisions or explosions.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"82 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141350235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-11DOI: 10.1177/13694332241260139
Jianwei Zhang, Fei Wang, Di Zhao, Wanlin Cao
The seismic behavior of six corroded recycled aggregate concrete (RAC) columns with ultra-high-strength bars (UHSB) was investigated through quasistatic test and numerical analysis. The main parameters include different corrosion ratios, axial load ratios (ALR), and stirrup ratios. The results revealed that: The damage development of the corroded specimen sped up with increasing corrosion ratio and ALR, and the corroded specimens suffered brittle shear failure due to the stirrup fracture or the concrete failure. The difference in carrying capacity of the specimens with low corrosion ratios and ALR was relatively small, while the deformation capacity was significantly reduced with increasing corrosion ratios and ALR. Reinforcement corrosion had a minor effect on the strength and stiffness degradation but would reduce the maximum cumulative energy dissipation capacity. By combining residual drift and residual crack width, the corroded specimens all could meet the limit of repairable residual drift and crack width before 4% drift, showing satisfactory resilient performance. Based on the modified corrosion models of materials, the numerical analysis showed the detrimental and coupling impact of the high ALR, high corrosion ratio, and low stirrup ratio on the carrying and deformation capacity. Through numerical analysis data, an equation was proposed that can satisfactorily predict the peak drift of the corroded columns with UHSB.
{"title":"Hysteretic behavior of the corroded recycled aggregate concrete columns with ultra-high strength bars","authors":"Jianwei Zhang, Fei Wang, Di Zhao, Wanlin Cao","doi":"10.1177/13694332241260139","DOIUrl":"https://doi.org/10.1177/13694332241260139","url":null,"abstract":"The seismic behavior of six corroded recycled aggregate concrete (RAC) columns with ultra-high-strength bars (UHSB) was investigated through quasistatic test and numerical analysis. The main parameters include different corrosion ratios, axial load ratios (ALR), and stirrup ratios. The results revealed that: The damage development of the corroded specimen sped up with increasing corrosion ratio and ALR, and the corroded specimens suffered brittle shear failure due to the stirrup fracture or the concrete failure. The difference in carrying capacity of the specimens with low corrosion ratios and ALR was relatively small, while the deformation capacity was significantly reduced with increasing corrosion ratios and ALR. Reinforcement corrosion had a minor effect on the strength and stiffness degradation but would reduce the maximum cumulative energy dissipation capacity. By combining residual drift and residual crack width, the corroded specimens all could meet the limit of repairable residual drift and crack width before 4% drift, showing satisfactory resilient performance. Based on the modified corrosion models of materials, the numerical analysis showed the detrimental and coupling impact of the high ALR, high corrosion ratio, and low stirrup ratio on the carrying and deformation capacity. Through numerical analysis data, an equation was proposed that can satisfactorily predict the peak drift of the corroded columns with UHSB.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"15 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141360713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For some long span cable supported bridges, the longitudinal diaphragms in main girder are designed as steel truss to reduce structural self-weight. However, unanticipated fatigue cracking in critical details of longitudinal steel truss diaphragm may occur after only a few years of service, resulting in stiffness weakening and stress redistribution. Based on an actual cable-stayed bridge, this paper presents a fatigue analysis of longitudinal steel truss diaphragms and provide an effective strengthening measure to elongate the fatigue life. Using traffic information from bridge toll station, the fatigue vehicle models were established. Then, a multi-scale finite element (FE) model was developed to help determining critical details of potential cracking and calculating the vehicle induced stress. After obtaining the required parameters, fatigue life of the specific critical detail was estimated base on damage accumulation law. The result agrees well with field observation. To ensure the performance of steel girder, the strengthening measure that replace diagonal tubes in longitudinal steel truss diaphragm with bolted channel steels was proposed and then applied. The assessment result indicated that the provided strengthening measure achieves satisfactory effects. It can also provide experience and partial reference for maintenance of similar structures.
{"title":"Fatigue analysis and strengthening measure for longitudinal steel truss diaphragms in a cable-stayed bridge","authors":"Ziyuan Fan, Yuan Ren, Yi Li, Yuyu Song, Chao Deng, Xiang Xu, Qiao Huang","doi":"10.1177/13694332241260078","DOIUrl":"https://doi.org/10.1177/13694332241260078","url":null,"abstract":"For some long span cable supported bridges, the longitudinal diaphragms in main girder are designed as steel truss to reduce structural self-weight. However, unanticipated fatigue cracking in critical details of longitudinal steel truss diaphragm may occur after only a few years of service, resulting in stiffness weakening and stress redistribution. Based on an actual cable-stayed bridge, this paper presents a fatigue analysis of longitudinal steel truss diaphragms and provide an effective strengthening measure to elongate the fatigue life. Using traffic information from bridge toll station, the fatigue vehicle models were established. Then, a multi-scale finite element (FE) model was developed to help determining critical details of potential cracking and calculating the vehicle induced stress. After obtaining the required parameters, fatigue life of the specific critical detail was estimated base on damage accumulation law. The result agrees well with field observation. To ensure the performance of steel girder, the strengthening measure that replace diagonal tubes in longitudinal steel truss diaphragm with bolted channel steels was proposed and then applied. The assessment result indicated that the provided strengthening measure achieves satisfactory effects. It can also provide experience and partial reference for maintenance of similar structures.","PeriodicalId":505409,"journal":{"name":"Advances in Structural Engineering","volume":"2 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141359071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-06DOI: 10.1177/13694332241260129
Hengming Zhang, Da Li, Feng Li
For slender FRP columns, predicting the global buckling critical loads is crucial in structural design. However, there is a lack of a consensus prediction method based on specialized domain knowledge. To address this issue, this study created a comprehensive database by collecting 365 experimental data related to global buckling of axially loaded pultruded FRP columns to predict buckling critical loads using such machine learning methods as extreme gradient boosting, artificial neural network, and support vector regression. The prediction accuracy and stability of the machine learning prediction methods were evaluated, and the interpretability of the features was analyzed in depth. The results show that the prediction accuracy of the traditional theoretical methods is low, while that of the machine learning methods is high. The contribution of geometric parameters to the buckling critical load is more than 80%. The contribution of material parameters to the buckling critical load is small, less than 20%. The cross-sectional moment of inertia has the most significant effect on the buckling critical load, while the shear modulus and compressive strength have a smaller effect.
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