Pub Date : 2025-01-12DOI: 10.1016/j.engstruct.2025.119611
Ao Zhou, Pan Gao, Bing Zhang, Kexuan Li, Chenchen Luan, Tiejun Liu
The degradation of basalt fiber reinforced polymer (BFRP) bars in alkaline environment affects their bond performance with concrete and limits their application as reinforcing materials. To address this issue, this study explores the use of geopolymer concrete as a replacement for traditional concrete, examining how the alkalinity of geopolymer affects the bond durability between BFRP bars and geopolymer concrete. The deterioration of bond performance and physicochemical properties were studied through pull-out tests and microscale characterization. After exposure at 55 °C for 135 days, the bond stress retention for specimens with a low pH level of 11.74 was 73 %. Reducing the alkalinity helps to minimize BFRP bar degradation by decreasing debonding at the fiber-resin interface and reducing fiber cracking. The revised chemical etching theory predicts the time required for the long-term bond strength retention of specimens with controlled alkalinity to decrease to 70 %. Additionally, a new bond-slip model is proposed to describe the bond-slip behavior between BFRP bars and geopolymer concrete. This study provides insight into using low-alkalinity geopolymer to mitigate the deterioration of bond performance between BFRP bars and concrete.
{"title":"Experimental and analytical investigation of long-term bond performance of basalt FRP-geopolymer concrete with varying alkalinities in marine environment","authors":"Ao Zhou, Pan Gao, Bing Zhang, Kexuan Li, Chenchen Luan, Tiejun Liu","doi":"10.1016/j.engstruct.2025.119611","DOIUrl":"10.1016/j.engstruct.2025.119611","url":null,"abstract":"<div><div>The degradation of basalt fiber reinforced polymer (BFRP) bars in alkaline environment affects their bond performance with concrete and limits their application as reinforcing materials. To address this issue, this study explores the use of geopolymer concrete as a replacement for traditional concrete, examining how the alkalinity of geopolymer affects the bond durability between BFRP bars and geopolymer concrete. The deterioration of bond performance and physicochemical properties were studied through pull-out tests and microscale characterization. After exposure at 55 °C for 135 days, the bond stress retention for specimens with a low pH level of 11.74 was 73 %. Reducing the alkalinity helps to minimize BFRP bar degradation by decreasing debonding at the fiber-resin interface and reducing fiber cracking. The revised chemical etching theory predicts the time required for the long-term bond strength retention of specimens with controlled alkalinity to decrease to 70 %. Additionally, a new bond-slip model is proposed to describe the bond-slip behavior between BFRP bars and geopolymer concrete. This study provides insight into using low-alkalinity geopolymer to mitigate the deterioration of bond performance between BFRP bars and concrete.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119611"},"PeriodicalIF":5.6,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143102737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119629
Xue-Chun Liu , Xu-Ze Feng , Xuesen Chen , Wei Zhou , Bin Xu , Zheng Yin
To investigate the fire resistance of L-section fireproof board and thin concrete encased steel (L-FBTCES) column, four columns were tested under constant axial compression and ISO-834 standard fire, varying the load ratio and concrete encasement thickness. The failure modes, thermal response, deformation response, and fire resistance time were obtained. The thermal response curve of the steel exhibited three stages, and the maximum temperature of the steel was below 600°C during the test. The fire resistance time for all specimens exceeded 120 minutes. The resistance time decreased with the increase of the load ratio and slightly increased with the increase of the concrete encasement. The thermo-mechanical coupling models were established, and the numerical parametrical analysis was conducted. Based on the existing specifications for composite columns and considering the adjusted load ratio and fireproof board thickness, a modified calculation method for L-FBTCES columns was proposed and validated by the numerical analysis results.
{"title":"Fire resistance performance of L-section fireproof board and thin concrete encased skeleton steel column","authors":"Xue-Chun Liu , Xu-Ze Feng , Xuesen Chen , Wei Zhou , Bin Xu , Zheng Yin","doi":"10.1016/j.engstruct.2025.119629","DOIUrl":"10.1016/j.engstruct.2025.119629","url":null,"abstract":"<div><div>To investigate the fire resistance of L-section fireproof board and thin concrete encased steel (L-FBTCES) column, four columns were tested under constant axial compression and ISO-834 standard fire, varying the load ratio and concrete encasement thickness. The failure modes, thermal response, deformation response, and fire resistance time were obtained. The thermal response curve of the steel exhibited three stages, and the maximum temperature of the steel was below 600°C during the test. The fire resistance time for all specimens exceeded 120 minutes. The resistance time decreased with the increase of the load ratio and slightly increased with the increase of the concrete encasement. The thermo-mechanical coupling models were established, and the numerical parametrical analysis was conducted. Based on the existing specifications for composite columns and considering the adjusted load ratio and fireproof board thickness, a modified calculation method for L-FBTCES columns was proposed and validated by the numerical analysis results.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119629"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119679
Chenlong Lin, Yuhong Yan, Zhenzhen Liu, Yiyan Lu
The combination of seawater sea-sand engineered cementitious composites (SS-ECCs) and the fiber-reinforced polymer (FRP) is a new type of structural form that overcomes the defects of reinforced concrete (RC) structures, such as the difficulty in obtaining raw materials and susceptibility to corrosion constructions of offshore islands and reefs. This study proposed a new type of FRP SS-ECC composite slab that uses FRP profiles as the bottom mold and bottom tension component and replaces traditional concrete with the SS-ECC. The slabs were tested under different loading conditions, including four-point bending, center single-line loading, and single-point loading at different locations. The load-deflection response, damage pattern, strain characteristics, and energy absorption were analyzed. The load-bearing capacity of the composite slab was the highest under the four-point bending condition. Single-point eccentric loading was a more unfavorable working condition for the composite slab, wherein the slab consumed less energy and failed earlier. The varying degrees of shear tearing of the side plate of the FRP profile were the main causes of specimen failure. The longitudinal strain changes in the FRP profile at the bottom were uniform, whereas the force conditions, strain variations, and distributions of T-ribs and GFRP bars varied considerably depending on the loading conditions. Composite slabs did not have the same ductility as RC slabs, and their energy absorption was lower than that of RC slabs. However, the bearing capacity of composite slabs was significantly greater than that of RC slabs, and composite slabs exhibited a large residual bearing capacity after peak failure.
{"title":"Behavior of FRP seawater sea-sand ECC composite slabs under different loading conditions","authors":"Chenlong Lin, Yuhong Yan, Zhenzhen Liu, Yiyan Lu","doi":"10.1016/j.engstruct.2025.119679","DOIUrl":"10.1016/j.engstruct.2025.119679","url":null,"abstract":"<div><div>The combination of seawater sea-sand engineered cementitious composites (SS-ECCs) and the fiber-reinforced polymer (FRP) is a new type of structural form that overcomes the defects of reinforced concrete (RC) structures, such as the difficulty in obtaining raw materials and susceptibility to corrosion constructions of offshore islands and reefs. This study proposed a new type of FRP SS-ECC composite slab that uses FRP profiles as the bottom mold and bottom tension component and replaces traditional concrete with the SS-ECC. The slabs were tested under different loading conditions, including four-point bending, center single-line loading, and single-point loading at different locations. The load-deflection response, damage pattern, strain characteristics, and energy absorption were analyzed. The load-bearing capacity of the composite slab was the highest under the four-point bending condition. Single-point eccentric loading was a more unfavorable working condition for the composite slab, wherein the slab consumed less energy and failed earlier. The varying degrees of shear tearing of the side plate of the FRP profile were the main causes of specimen failure. The longitudinal strain changes in the FRP profile at the bottom were uniform, whereas the force conditions, strain variations, and distributions of T-ribs and GFRP bars varied considerably depending on the loading conditions. Composite slabs did not have the same ductility as RC slabs, and their energy absorption was lower than that of RC slabs. However, the bearing capacity of composite slabs was significantly greater than that of RC slabs, and composite slabs exhibited a large residual bearing capacity after peak failure.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119679"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119636
Guanghao Zhai , Billie F. Spencer , Jinhui Yan , Wenjie Liao , Donglian Gu , Carlotta Pia Contiguglia , Cristoforo Demartino , Yongjia Xu
Achieving accurate and computational efficient simulations is vital for the design, construction, and maintenance of buildings and infrastructures. Traditional physics-driven methods, such as the finite element method, struggle to balance precision with computational efficiency. In contrast, data-driven methods, such as deep neural networks, fall short in generalization and robustness. Therefore, this study proposes a coupled data/physics-driven simulation framework to harness the advantages of data- and physics-driven models, to achieve accurate and computational-efficient structural response simulation. First, the overall concept of the proposed framework is outlined, including modeling and separating the target structure into data- and physics-driven sections. Based on the discussion of the fundamental approaches for data-driven simulation, an innovative attention-enhanced stacked regression neural network is proposed to improve the accuracy of data-driven section. This architecture integrates dataset augmentation method, stacked regression, and attention-based feature enhancement. Furthermore, physics-driven modeling and the integration between the data- and physics-driven models are investigated. Finally, a case study is conducted based on a three-story frame/shear-wall building. The results demonstrate that the proposed method achieves accuracy comparable to refined finite element models, with an average stress/strain deviation no more than 0.1 %. Meanwhile, the required computational time is similar to that of a much-simplified model, with a speed-up ratio exceeding 70 times.
{"title":"Coupled data/physics-driven framework for accurate and efficient structural response simulation","authors":"Guanghao Zhai , Billie F. Spencer , Jinhui Yan , Wenjie Liao , Donglian Gu , Carlotta Pia Contiguglia , Cristoforo Demartino , Yongjia Xu","doi":"10.1016/j.engstruct.2025.119636","DOIUrl":"10.1016/j.engstruct.2025.119636","url":null,"abstract":"<div><div>Achieving accurate and computational efficient simulations is vital for the design, construction, and maintenance of buildings and infrastructures. Traditional physics-driven methods, such as the finite element method, struggle to balance precision with computational efficiency. In contrast, data-driven methods, such as deep neural networks, fall short in generalization and robustness. Therefore, this study proposes a coupled data/physics-driven simulation framework to harness the advantages of data- and physics-driven models, to achieve accurate and computational-efficient structural response simulation. First, the overall concept of the proposed framework is outlined, including modeling and separating the target structure into data- and physics-driven sections. Based on the discussion of the fundamental approaches for data-driven simulation, an innovative attention-enhanced stacked regression neural network is proposed to improve the accuracy of data-driven section. This architecture integrates dataset augmentation method, stacked regression, and attention-based feature enhancement. Furthermore, physics-driven modeling and the integration between the data- and physics-driven models are investigated. Finally, a case study is conducted based on a three-story frame/shear-wall building. The results demonstrate that the proposed method achieves accuracy comparable to refined finite element models, with an average stress/strain deviation no more than 0.1 %. Meanwhile, the required computational time is similar to that of a much-simplified model, with a speed-up ratio exceeding 70 times.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119636"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119642
Xiaoqiang Yang , Liguo Zhu , Kaiming Bi , Hui Zhao , Yong Zhu , Zhichao Lai
High-performance concrete-filled steel tube (CFST) members consisting of high-strength steel and ultra-high performance concrete (UHPC) are more and more widely applied in modern engineering structures. These structures/structural components may suffer from axial impact loading during its life cycle such as impact induced by the collapse of top-level floors. However, the design and evaluation methods for axial impact resistance remain unclear for these structures. This paper presented a systematic study on both the impact and post-impact resistances of high-performance CFST members subjected to axial impact. A database of CFST members subjected to axial impact was first compiled, and a finite element (FE) model was established and verified by the test results from the compiled database. The effects of key parameters on the impact resistances and residual capacity of square UHPC-filled high-strength steel tubes under axial impact were clarified. By employing 420 FE models of square CFST columns subjected to axial impact with random parameters, equations for predicting the maximum axial displacement under axial impact and axial residual bearing capacity after axial impact that are suitable for conventional and high-performance CFST columns (fy ≤ 960 MPa and fcu ≤ 200 MPa) were developed with reasonable accuracy. Finally, a maximum deformation limit was recommended for CFST components subjected to axial impact, which provides a reference for anti-impact design and evaluation for general high-performance CFST members.
{"title":"Design and evaluation methods for CFST members with high-performance materials subjected to axial impact","authors":"Xiaoqiang Yang , Liguo Zhu , Kaiming Bi , Hui Zhao , Yong Zhu , Zhichao Lai","doi":"10.1016/j.engstruct.2025.119642","DOIUrl":"10.1016/j.engstruct.2025.119642","url":null,"abstract":"<div><div>High-performance concrete-filled steel tube (CFST) members consisting of high-strength steel and ultra-high performance concrete (UHPC) are more and more widely applied in modern engineering structures. These structures/structural components may suffer from axial impact loading during its life cycle such as impact induced by the collapse of top-level floors. However, the design and evaluation methods for axial impact resistance remain unclear for these structures. This paper presented a systematic study on both the impact and post-impact resistances of high-performance CFST members subjected to axial impact. A database of CFST members subjected to axial impact was first compiled, and a finite element (FE) model was established and verified by the test results from the compiled database. The effects of key parameters on the impact resistances and residual capacity of square UHPC-filled high-strength steel tubes under axial impact were clarified. By employing 420 FE models of square CFST columns subjected to axial impact with random parameters, equations for predicting the maximum axial displacement under axial impact and axial residual bearing capacity after axial impact that are suitable for conventional and high-performance CFST columns (<em>f</em><sub>y</sub> ≤ 960 MPa and <em>f</em><sub>cu</sub> ≤ 200 MPa) were developed with reasonable accuracy. Finally, a maximum deformation limit was recommended for CFST components subjected to axial impact, which provides a reference for anti-impact design and evaluation for general high-performance CFST members.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119642"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119634
C. Guzman , G. Araya-Letelier , R. Astroza , E. Miranda , M.F. Gallegos
Extensive evidence indicates that steel-frame (SF) gypsum-board (GB) partitions are susceptible to seismic damage from very small story drift ratio (SDR) demands, which can lead to significant economic losses, environmental impacts, and downtime in buildings. To mitigate this risk, several innovations have been developed in SF-GB partitions, among which the use of adhesive connections (ACs) recently stands out as a replacement strategy to screw connections (SCs) for attaching GBs to SFs. The use of ACs has shown significant increments in both strength and stiffness of partitions, compared to partitions with SCs. However, the behavior of ACs has been studied mainly under in-plane loads and without a detailed analysis of the use of ACs in the reduction of damage states (DSs) neither the generation of fragility curves. This research presents an experimental study of 36 full-scale SF-GB panels, where the structural behavior under out-of-plane loads of SC-SF-GB and AC-SF-GB panels, as well as other design variables such as GB thickness and type of SF, are assessed and compared in terms of strength, stiffness, and DS evolution. The results of the test campaign show that the mean strength and stiffness of AC-SF-GB panels are 101 % and 47 % higher than those of the SC-SF-GB panels, respectively. In addition, AC-SF-GB panels exhibit a better performance compared to SC-SF-GB panels in terms of DS evolution. The results indicate that the type of connection is a design variable with significant impact on the strength, stiffness, and damage evolution of partitions, over the GB thickness and the type of SF. Finally, the developed fragility functions, which pass the goodness-of-fit tests, confirm the enhanced seismic performance of the AC-GB-SF panels and are a key component to perform future loss estimation studies for building-specific assessments.
{"title":"Out-of-plane monotonic testing and fragility function development of screw and adhesive connections of steel-framed gypsum-board panels","authors":"C. Guzman , G. Araya-Letelier , R. Astroza , E. Miranda , M.F. Gallegos","doi":"10.1016/j.engstruct.2025.119634","DOIUrl":"10.1016/j.engstruct.2025.119634","url":null,"abstract":"<div><div>Extensive evidence indicates that steel-frame (SF) gypsum-board (GB) partitions are susceptible to seismic damage from very small story drift ratio (SDR) demands, which can lead to significant economic losses, environmental impacts, and downtime in buildings. To mitigate this risk, several innovations have been developed in SF-GB partitions, among which the use of adhesive connections (ACs) recently stands out as a replacement strategy to screw connections (SCs) for attaching GBs to SFs. The use of ACs has shown significant increments in both strength and stiffness of partitions, compared to partitions with SCs. However, the behavior of ACs has been studied mainly under in-plane loads and without a detailed analysis of the use of ACs in the reduction of damage states (DSs) neither the generation of fragility curves. This research presents an experimental study of 36 full-scale SF-GB panels, where the structural behavior under out-of-plane loads of SC-SF-GB and AC-SF-GB panels, as well as other design variables such as GB thickness and type of SF, are assessed and compared in terms of strength, stiffness, and DS evolution. The results of the test campaign show that the mean strength and stiffness of AC-SF-GB panels are 101 % and 47 % higher than those of the SC-SF-GB panels, respectively. In addition, AC-SF-GB panels exhibit a better performance compared to SC-SF-GB panels in terms of DS evolution. The results indicate that the type of connection is a design variable with significant impact on the strength, stiffness, and damage evolution of partitions, over the GB thickness and the type of SF. Finally, the developed fragility functions, which pass the goodness-of-fit tests, confirm the enhanced seismic performance of the AC-GB-SF panels and are a key component to perform future loss estimation studies for building-specific assessments.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119634"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119658
Jun Wang , Shaodong Feng , Kai Zhang , Hu Ding
A large number of inclined beam structures suffer from vibration problems. In this paper, the transverse nonlinear vibration model of an inclined beam is established for the first time to study the influence of the inclination angle. Moreover, a nonlinear energy sink (NES) is introduced to control the forced vibration of the inclined beam. The nontrivial static equilibrium configuration caused by weight is solved. Furthermore, the governing equation of the inclined beam-NES system is derived around static configuration. The effects of the inclination angle on the natural frequencies are studied. Meanwhile, the nonlinear dynamic response of the coupled system is analyzed qualitatively and verified numerically. The results show that the decrease in the inclination angle tends to increase the natural frequencies. Moreover, the low-order natural frequency of the system is more sensitive to the influence of the inclination angle and cannot be ignored. In addition, the research shows that the inclination angle affects the parameter design of NES. However, suitable parameters of the NES can achieve superior damping efficiency for vibration control of inclined beams at different angles of inclination. Thus, this research proposes a novel model for inclined engineering structures and provides the necessary theoretical basis for designing NES to reduce vibration.
{"title":"Transverse vibration suppression of an inclined beam with a nonlinear energy sink","authors":"Jun Wang , Shaodong Feng , Kai Zhang , Hu Ding","doi":"10.1016/j.engstruct.2025.119658","DOIUrl":"10.1016/j.engstruct.2025.119658","url":null,"abstract":"<div><div>A large number of inclined beam structures suffer from vibration problems. In this paper, the transverse nonlinear vibration model of an inclined beam is established for the first time to study the influence of the inclination angle. Moreover, a nonlinear energy sink (NES) is introduced to control the forced vibration of the inclined beam. The nontrivial static equilibrium configuration caused by weight is solved. Furthermore, the governing equation of the inclined beam-NES system is derived around static configuration. The effects of the inclination angle on the natural frequencies are studied. Meanwhile, the nonlinear dynamic response of the coupled system is analyzed qualitatively and verified numerically. The results show that the decrease in the inclination angle tends to increase the natural frequencies. Moreover, the low-order natural frequency of the system is more sensitive to the influence of the inclination angle and cannot be ignored. In addition, the research shows that the inclination angle affects the parameter design of NES. However, suitable parameters of the NES can achieve superior damping efficiency for vibration control of inclined beams at different angles of inclination. Thus, this research proposes a novel model for inclined engineering structures and provides the necessary theoretical basis for designing NES to reduce vibration.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119658"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119614
Lidan Mei , Mingtao Wu , Tao Li , Tianyu Li , Hao Du , Xiamin Hu
This paper investigates a novel unbonded prestressed bamboo scrimber-steel composite beam by embedding steel tubes within bamboo scrimber to form channels, through which steel bars are threaded and prestressed after shaping. Four-point bending tests were conducted to evaluate the effects of reinforcement ratio and prestress level on the short-term flexural behavior of the beam. The failure modes, load-midspan deflection, ultimate bearing capacity, stiffness, and strain distribution of the beams were analyzed based on the experimental data. The test result showed bamboo scrimber beams strengthened with steel with a reinforcement ratio ranging from 1.84 % to 5.23 % experienced a significant increase in ultimate bearing capacity of 5.64∼29.09 % and an increase in flexural stiffness of 5.71∼24.31 %. Flexural stiffness increases with the reinforcement ratio. Enhancing both the reinforcement ratio and prestress level effectively improves ultimate bearing capacity. However, as the reinforcement ratio increases, the impact of increasing the prestress level on improving ultimate bearing capacity diminished. Based on the deformation model of unbonded prestress bars, a theoretical model for the ultimate bearing capacity of the unbonded prestressed bamboo scrimber-steel composite beams was established. The calculated value of the bearing capacity was in good agreement with the test results.
{"title":"Experimental and theoretical investigation of short-term behavior of unbonded prestressed bamboo scrimber-steel composite beams","authors":"Lidan Mei , Mingtao Wu , Tao Li , Tianyu Li , Hao Du , Xiamin Hu","doi":"10.1016/j.engstruct.2025.119614","DOIUrl":"10.1016/j.engstruct.2025.119614","url":null,"abstract":"<div><div>This paper investigates a novel unbonded prestressed bamboo scrimber-steel composite beam by embedding steel tubes within bamboo scrimber to form channels, through which steel bars are threaded and prestressed after shaping. Four-point bending tests were conducted to evaluate the effects of reinforcement ratio and prestress level on the short-term flexural behavior of the beam. The failure modes, load-midspan deflection, ultimate bearing capacity, stiffness, and strain distribution of the beams were analyzed based on the experimental data. The test result showed bamboo scrimber beams strengthened with steel with a reinforcement ratio ranging from 1.84 % to 5.23 % experienced a significant increase in ultimate bearing capacity of 5.64∼29.09 % and an increase in flexural stiffness of 5.71∼24.31 %. Flexural stiffness increases with the reinforcement ratio. Enhancing both the reinforcement ratio and prestress level effectively improves ultimate bearing capacity. However, as the reinforcement ratio increases, the impact of increasing the prestress level on improving ultimate bearing capacity diminished. Based on the deformation model of unbonded prestress bars, a theoretical model for the ultimate bearing capacity of the unbonded prestressed bamboo scrimber-steel composite beams was established. The calculated value of the bearing capacity was in good agreement with the test results.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119614"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shape memory alloys (SMAs) are a well-known type of smart material that recovers its original shapes upon activation. This unique property makes SMAs attractive for pre-stressing applications in civil engineering. Iron-based SMAs (Fe-SMAs) are particularly promising for civil engineering applications because of their low cost, high stiffness, and large recovery force generation. The activation of Fe-SMAs embedded in concrete involves four main physical processes: electrical current flow, heat generation and transfer, stress generation, and phase transformation. A multiphysical simulation of the Fe-SMA activation is performed in the present study, considering the interaction of the involved physical models. The verification of the model is done in multiple steps, by comparing the simulation results with the available experimental results on Fe-SMA activation. Following the model verification, a parametric study is done to investigate the effective activation, and geometrical parameters on the heat, and stress distributions. The model provides a reliable tool for understanding the behavior of the embedded Fe-SMA reinforcement and surrounding concrete during activation. It also aids in designing the appropriate activation and geometrical parameters for SMA-reinforced concrete structures, based on the required mechanical properties of the structure.
{"title":"Multiphysical simulation of iron-based shape memory alloy (Fe-SMA) activation embedded in concrete structures","authors":"Ali Saeedi , Alireza Tabrizikahou , Paul-Remo Wagner , Moslem Shahverdi","doi":"10.1016/j.engstruct.2025.119623","DOIUrl":"10.1016/j.engstruct.2025.119623","url":null,"abstract":"<div><div>Shape memory alloys (SMAs) are a well-known type of smart material that recovers its original shapes upon activation. This unique property makes SMAs attractive for pre-stressing applications in civil engineering. Iron-based SMAs (Fe-SMAs) are particularly promising for civil engineering applications because of their low cost, high stiffness, and large recovery force generation. The activation of Fe-SMAs embedded in concrete involves four main physical processes: electrical current flow, heat generation and transfer, stress generation, and phase transformation. A multiphysical simulation of the Fe-SMA activation is performed in the present study, considering the interaction of the involved physical models. The verification of the model is done in multiple steps, by comparing the simulation results with the available experimental results on Fe-SMA activation. Following the model verification, a parametric study is done to investigate the effective activation, and geometrical parameters on the heat, and stress distributions. The model provides a reliable tool for understanding the behavior of the embedded Fe-SMA reinforcement and surrounding concrete during activation. It also aids in designing the appropriate activation and geometrical parameters for SMA-reinforced concrete structures, based on the required mechanical properties of the structure.</div></div>","PeriodicalId":11763,"journal":{"name":"Engineering Structures","volume":"327 ","pages":"Article 119623"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143103161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.engstruct.2025.119628
Alexander Lin , Hanmo Wang , Wei He , Shawn Owyong , Huan Ting Chen , Tam H. Nguyen
Lightweight, non-structural concrete partition walls with customized hollow sections enhance earthquake resilience, particularly by optimizing horizontal stiffness to resist lateral forces in seismic engineering. However, exhaustive search of the entire design space to optimize horizontal stiffness is time-consuming. Therefore, this research aims to develop a classifier to filter out less promising sections, reducing the search space and improving efficiency. Combining Graph Neural Networks (GNNs) and Bayesian Neural Networks (BNNs) offers computational- and time-efficient solutions for classification tasks applicable to the design of hollow building components. However, the impact of different BNN configurations within this hybrid remains underexplored. To address this, we proposed and compared eight hybrid models with different BNNs to identify the optimal hybrid model based on classification accuracy. Results show that the BNN featuring a Bayesian layer followed by two linear layers (BLL) is most effective, achieving around 90 % classification accuracy in both training and testing datasets. To assess search space reduction, we test the models on 2000 samples. The hybrid model featuring BLL in its BNN achieves the best performance, with a 26.85 % search space reduction in the search space. Compared to a traditional statistical model, which achieves a 17.7 % search space reduction, the optimal hybrid model demonstrates superior effectiveness. The present study focuses on single-objective optimization, specifically targeting the performance of horizontal stiffness in directions more sensitive to the configuration change of morphed honeycomb channels in the hollow component. Future work will expand to multi-objective optimization, concurrently considering other mechanical properties for a more comprehensive optimization.
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