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2026, Volume 56, Issue 7
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2026,
56(7):
1-10.
doi: 10.3724/j.gyjzG25030614
Abstract:
Under the background of upholding cultural self-confidence and promoting high-quality urban development， industrial historical space， as an important carrier of industrial culture， require deepening in theoretical research， method innovation， and practical exploration. Using CiteSpace and HistCite as quantitative knowledge mapping analysis tools， this study systematically reviews and deeply interprets Chinese and international research on industrial historical space over the two decades. The analysis reveals that the discussions on industrial heritage constitutes a key element and a significant proportion of the industrial historical space research system. On this basis， this review further focuses on industrial historical space， including its conceptual connotation， spatial evaluation， spatial characteristics， spatial preservation and transformation， as well as multi-dimensional perception of space. In view of the limitations and deficiencies of existing research， combined with the existing foundation of historical space research， this paper proposes future research directions for industrial historical space. It aims to provide new ideas and strategies for deepening the construction of historical and cultural preservation systems and for achieving the sustainable development of old industrial cities.
Under the background of upholding cultural self-confidence and promoting high-quality urban development， industrial historical space， as an important carrier of industrial culture， require deepening in theoretical research， method innovation， and practical exploration. Using CiteSpace and HistCite as quantitative knowledge mapping analysis tools， this study systematically reviews and deeply interprets Chinese and international research on industrial historical space over the two decades. The analysis reveals that the discussions on industrial heritage constitutes a key element and a significant proportion of the industrial historical space research system. On this basis， this review further focuses on industrial historical space， including its conceptual connotation， spatial evaluation， spatial characteristics， spatial preservation and transformation， as well as multi-dimensional perception of space. In view of the limitations and deficiencies of existing research， combined with the existing foundation of historical space research， this paper proposes future research directions for industrial historical space. It aims to provide new ideas and strategies for deepening the construction of historical and cultural preservation systems and for achieving the sustainable development of old industrial cities.
2026,
56(7):
11-18.
doi: 10.3724/j.gyjzG25012503
Abstract:
Urban blocks are characterized by spatial intensification and high resource consumption. Considering that building energy consumption accounts for a significant portion of total energy consumption， studying carbon emission control in urban block engineering construction is of great importance for reducing urban carbon emissions. In response to the current lack of evaluation methods for the carbon emission control level in urban block engineering construction， this paper collected relevant evaluation indicators for low-carbon cities， and then applied the TF-IDF algorithm and LDA model to analyze the indicator themes， establishing a carbon emission control maturity evaluation model with the Capability Maturity Model as the theoretical framework. The model indicators cover the management system， technology system， and sustainability system， and benchmark values for quantifiable indicators were proposed. Furthermore， an application study was conducted through three engineering project cases， and differentiated optimization suggestions for control are proposed according to the maturity evaluation results， including linkage control， data feedback and AI empowerment.
Urban blocks are characterized by spatial intensification and high resource consumption. Considering that building energy consumption accounts for a significant portion of total energy consumption， studying carbon emission control in urban block engineering construction is of great importance for reducing urban carbon emissions. In response to the current lack of evaluation methods for the carbon emission control level in urban block engineering construction， this paper collected relevant evaluation indicators for low-carbon cities， and then applied the TF-IDF algorithm and LDA model to analyze the indicator themes， establishing a carbon emission control maturity evaluation model with the Capability Maturity Model as the theoretical framework. The model indicators cover the management system， technology system， and sustainability system， and benchmark values for quantifiable indicators were proposed. Furthermore， an application study was conducted through three engineering project cases， and differentiated optimization suggestions for control are proposed according to the maturity evaluation results， including linkage control， data feedback and AI empowerment.
2026,
56(7):
19-31.
doi: 10.3724/j.gyjzG25070708
Abstract:
In recent years， the revitalization of outdoor public spaces at railway heritage sites has become a key research focus， but many interventions fail to sustain long-term spatial vitality and balanced functional performance. Taking Bisezhai Station along the Yunnan-Vietnam Railway as a case study， this paper proposes a multi-dimensional evaluation system for outdoor spatial quality based on the human behavioral chain of “perception， arrival， and stay” and the physical environmental characteristics.Specifically， the research includes two core parts：establishing a comprehensive evaluation framework encompassing “accessibility， openness， and thermal comfort” to demonstrate a positive correlation between physical environment quality and spatial vitality；proposing a hierarchical optimization strategy of “attribute optimization， spatial system refinement， and activity customization” to guide the physical environment improvements at Bisezhai Station. This study thus provides a replicable practical model for the revitalization of outdoor spaces at the Yunnan-Vietnam Railway and other railway heritage sites.
In recent years， the revitalization of outdoor public spaces at railway heritage sites has become a key research focus， but many interventions fail to sustain long-term spatial vitality and balanced functional performance. Taking Bisezhai Station along the Yunnan-Vietnam Railway as a case study， this paper proposes a multi-dimensional evaluation system for outdoor spatial quality based on the human behavioral chain of “perception， arrival， and stay” and the physical environmental characteristics.Specifically， the research includes two core parts：establishing a comprehensive evaluation framework encompassing “accessibility， openness， and thermal comfort” to demonstrate a positive correlation between physical environment quality and spatial vitality；proposing a hierarchical optimization strategy of “attribute optimization， spatial system refinement， and activity customization” to guide the physical environment improvements at Bisezhai Station. This study thus provides a replicable practical model for the revitalization of outdoor spaces at the Yunnan-Vietnam Railway and other railway heritage sites.
2026,
56(7):
32-41.
doi: 10.3724/j.gyjzG25100401
Abstract:
The formation of railway linear cultural heritage has facilitated the development of modern and contemporary Chinese cities， constituting a crucial part of industrial civilization．The heritage encompasses numerous elements， including not only the heritage assets themselves but also their surrounding social environment．A systematic and holistic approach to its conservation and utilization is therefore essential to maximize the efficiency of this existing resource．Taking the Zhengtai Railway as an example， this paper outlines its spatio-temporal evolution characteristics and applies the “Circle Structure Theory”. Centered on the primary function of transportation， a core-auxiliary-derivative layer framework is established to optimize the coverage content of the system．By analyzing the impact of railways on spatial layout， economic industries， population flow and other aspects along the lines， this study deepens the understanding of the heritage’s value. Finally， it explores holistic pathways for conservation and utilization path that meet the needs of urban renewal， providing insights for subsequent theoretical and practical research in this field.
The formation of railway linear cultural heritage has facilitated the development of modern and contemporary Chinese cities， constituting a crucial part of industrial civilization．The heritage encompasses numerous elements， including not only the heritage assets themselves but also their surrounding social environment．A systematic and holistic approach to its conservation and utilization is therefore essential to maximize the efficiency of this existing resource．Taking the Zhengtai Railway as an example， this paper outlines its spatio-temporal evolution characteristics and applies the “Circle Structure Theory”. Centered on the primary function of transportation， a core-auxiliary-derivative layer framework is established to optimize the coverage content of the system．By analyzing the impact of railways on spatial layout， economic industries， population flow and other aspects along the lines， this study deepens the understanding of the heritage’s value. Finally， it explores holistic pathways for conservation and utilization path that meet the needs of urban renewal， providing insights for subsequent theoretical and practical research in this field.
2026,
56(7):
42-51.
doi: 10.3724/j.gyjzG25122903
Abstract:
In the context of urban renewal that emphasizes both “cultural memory inheritance” and “spatial scene translation”， the adaptive reuse of old industrial plants into art galleries has become a significant practice. However， the coupling mechanisms between old and new spaces and the pathways for cultural information translation in this transformation require deeper analysis. From the theoretical perspective of spatial coupling， and through a comparative analysis of spatial conditions before and after adaptive reuse in typical cases， this study deciphers the intrinsic logic of interaction between industrial heritage attributes and the functional requirements of art galleries. This study reveals that the adaptive reuse of spatial functions primarily achieves coupling across two dimensions—the physical architectural spatial system and the perceptual experience system—through specific spatial translation pathways： juxtaposition， contrast， integration， and guidance. Consequently， an adaptive design model structured at three levels is formulated： macro-positioning （serving as urban landmark anchors and community engines）， meso-organization （featuring linear series， hall nesting， and grid permeability based on the translation and reconfiguration of structural logic）， and micro-interface （employing trace visualization， material dialogue， and transparency intervention）.
In the context of urban renewal that emphasizes both “cultural memory inheritance” and “spatial scene translation”， the adaptive reuse of old industrial plants into art galleries has become a significant practice. However， the coupling mechanisms between old and new spaces and the pathways for cultural information translation in this transformation require deeper analysis. From the theoretical perspective of spatial coupling， and through a comparative analysis of spatial conditions before and after adaptive reuse in typical cases， this study deciphers the intrinsic logic of interaction between industrial heritage attributes and the functional requirements of art galleries. This study reveals that the adaptive reuse of spatial functions primarily achieves coupling across two dimensions—the physical architectural spatial system and the perceptual experience system—through specific spatial translation pathways： juxtaposition， contrast， integration， and guidance. Consequently， an adaptive design model structured at three levels is formulated： macro-positioning （serving as urban landmark anchors and community engines）， meso-organization （featuring linear series， hall nesting， and grid permeability based on the translation and reconfiguration of structural logic）， and micro-interface （employing trace visualization， material dialogue， and transparency intervention）.
2026,
56(7):
52-62.
doi: 10.3724/j.gyjzG25030607
Abstract:
To address the construction difficulties caused by excessively small stirrup spacing in reinforced concrete columns with high seismic demands， as well as the issue of stirrup “unlocking”， this study proposed a concrete column confined by bidirectional spiral stirrups and conducted a finite element analysis on its seismic performance. Drawing upon existing experimental research， numerical simulations were performed using ABAQUS software， and the model’s validity was verified. Based on the validated model， the effects of various parameters， including the axial compression ratio， concrete strength， stirrup spacing， stirrup diameter， and stirrup configuration， on the seismic performance were systematically analyzed. Furthermore， the confinement effect of thin-walled circular steel tubular columns with an equivalent volumetric steel ratio was investigated for comparison. The results indicated that the ductility of the concrete columns decreased as the axial compression ratio increased. In contrast， the bearing capacity initially increased with increasing axial compression ratio but began to decline after the ratio exceeded 0.5. Higher concrete strength and larger stirrup spacing led to reduced ductility. While increased concrete strength enhanced the bearing capacity， larger stirrup spacing reduced it. Increasing the stirrup diameter improved both ductility and bearing capacity. Under identical stirrup spacing， the concrete columns with bidirectional spiral stirrups exhibited a higher bearing capacity than those with unidirectional spiral stirrups. For an equivalent volumetric stirrup ratio， the bidirectionally confined columns demonstrated better ductility than their unidirectional counterparts， without a significant compromise in bearing capacity. At an equivalent volumetric stirrup ratio， the concrete columns confined by bidirectional spiral stirrups demonstrated superior ductility and offered enhanced seismic performance compared to the thin-walled circular steel tubular columns.
To address the construction difficulties caused by excessively small stirrup spacing in reinforced concrete columns with high seismic demands， as well as the issue of stirrup “unlocking”， this study proposed a concrete column confined by bidirectional spiral stirrups and conducted a finite element analysis on its seismic performance. Drawing upon existing experimental research， numerical simulations were performed using ABAQUS software， and the model’s validity was verified. Based on the validated model， the effects of various parameters， including the axial compression ratio， concrete strength， stirrup spacing， stirrup diameter， and stirrup configuration， on the seismic performance were systematically analyzed. Furthermore， the confinement effect of thin-walled circular steel tubular columns with an equivalent volumetric steel ratio was investigated for comparison. The results indicated that the ductility of the concrete columns decreased as the axial compression ratio increased. In contrast， the bearing capacity initially increased with increasing axial compression ratio but began to decline after the ratio exceeded 0.5. Higher concrete strength and larger stirrup spacing led to reduced ductility. While increased concrete strength enhanced the bearing capacity， larger stirrup spacing reduced it. Increasing the stirrup diameter improved both ductility and bearing capacity. Under identical stirrup spacing， the concrete columns with bidirectional spiral stirrups exhibited a higher bearing capacity than those with unidirectional spiral stirrups. For an equivalent volumetric stirrup ratio， the bidirectionally confined columns demonstrated better ductility than their unidirectional counterparts， without a significant compromise in bearing capacity. At an equivalent volumetric stirrup ratio， the concrete columns confined by bidirectional spiral stirrups demonstrated superior ductility and offered enhanced seismic performance compared to the thin-walled circular steel tubular columns.
2026,
56(7):
63-71.
doi: 10.3724/j.gyjzG25011201
Abstract:
Axial compressive tests were performed on the square steel tubular slender column filled with geopolymer recycled brick aggregate concrete （FSSTSC-GRBAC） with different aggregate replacement ratios and slenderness ratios. The influence of failure modes， bearing capacity， ductility， and energy dissipation on the mechanical properties of FSSTSC-GRBAC were analyzed. The results showed that the mechanical properties of FSSTC-GRBAC under axial compression were similar to those of ordinary concrete-filled steel tube columns. The FSSTC-GRBAC experienced elastic， elastoplastic， and failure stages， and finally exhibited local instability failure. The bearing capacity and energy dissipation capacity decreased with the increase of the replacement ratio and slenderness ratio， while the ductility was improved. The influence of the slenderness ratio on bearing capacity was consistent and more significant. The bearing capacities of specimens with slenderness ratios of 42.64 and 63.95 were 0.73% and 20.89% lower， respectively， than that of the specimen with a slenderness ratio of 21.32. Analysis showed that the bearing capacity calculated using the methods in the Technical Code for Concrete Filled Steel Tubular Structures （GB 50936-2014）， the Technical Specification for Solid and Hollow Concrete-Filled Steel Tubular Structure （CECS 254∶2012）， and the Technical Specification for Concrete-Filled Steel Tubular Structures （DBJ/T 13-51-2020） exhibited a certain safety redundancy. This indicates that these standards are applicable for predicting the bearing capacity of GBARC-FSSTSC under axial compression.
Axial compressive tests were performed on the square steel tubular slender column filled with geopolymer recycled brick aggregate concrete （FSSTSC-GRBAC） with different aggregate replacement ratios and slenderness ratios. The influence of failure modes， bearing capacity， ductility， and energy dissipation on the mechanical properties of FSSTSC-GRBAC were analyzed. The results showed that the mechanical properties of FSSTC-GRBAC under axial compression were similar to those of ordinary concrete-filled steel tube columns. The FSSTC-GRBAC experienced elastic， elastoplastic， and failure stages， and finally exhibited local instability failure. The bearing capacity and energy dissipation capacity decreased with the increase of the replacement ratio and slenderness ratio， while the ductility was improved. The influence of the slenderness ratio on bearing capacity was consistent and more significant. The bearing capacities of specimens with slenderness ratios of 42.64 and 63.95 were 0.73% and 20.89% lower， respectively， than that of the specimen with a slenderness ratio of 21.32. Analysis showed that the bearing capacity calculated using the methods in the Technical Code for Concrete Filled Steel Tubular Structures （GB 50936-2014）， the Technical Specification for Solid and Hollow Concrete-Filled Steel Tubular Structure （CECS 254∶2012）， and the Technical Specification for Concrete-Filled Steel Tubular Structures （DBJ/T 13-51-2020） exhibited a certain safety redundancy. This indicates that these standards are applicable for predicting the bearing capacity of GBARC-FSSTSC under axial compression.
2026,
56(7):
72-80.
doi: 10.3724/j.gyjzG25071006
Abstract:
To investigate the application of autoclaved aerated concrete sandwich wall panels in low-rise integrated housing， quasi-static tests were conducted on composite walls with different construction measures and openings. The failure modes， bearing capacity， deformation capacity， stiffness degradation， and displacement ductility of three types of walls were comparatively analyzed. The test results showed that the composite walls of autoclaved aerated concrete sandwich panel composite wall exhibited good seismic performance， and their failure mode was a combined bending-shear failure. The practice of integral casting of construction columns and wall panels exhibited better bearing and deformation capacities compared to the separate casting of columns and panels， with a 37.7% increase in peak bearing capacity and a 74.3% increase in the ductility coefficient. The practice of creating openings in the walls weakened the overall stiffness of the walls， significantly reducing the structural bearing and deformation capacities. Appropriately increasing the axial compression ratio could enhance the shear performance of the wall. Based on the above results， a calculation method for the shear capacity of composite walls with autoclaved aerated concrete sandwich panels under seismic action was proposed， which can provide a theoretical basis for the engineering application of autoclaved aerated concrete low-rise and mid-rise integrated houses.
To investigate the application of autoclaved aerated concrete sandwich wall panels in low-rise integrated housing， quasi-static tests were conducted on composite walls with different construction measures and openings. The failure modes， bearing capacity， deformation capacity， stiffness degradation， and displacement ductility of three types of walls were comparatively analyzed. The test results showed that the composite walls of autoclaved aerated concrete sandwich panel composite wall exhibited good seismic performance， and their failure mode was a combined bending-shear failure. The practice of integral casting of construction columns and wall panels exhibited better bearing and deformation capacities compared to the separate casting of columns and panels， with a 37.7% increase in peak bearing capacity and a 74.3% increase in the ductility coefficient. The practice of creating openings in the walls weakened the overall stiffness of the walls， significantly reducing the structural bearing and deformation capacities. Appropriately increasing the axial compression ratio could enhance the shear performance of the wall. Based on the above results， a calculation method for the shear capacity of composite walls with autoclaved aerated concrete sandwich panels under seismic action was proposed， which can provide a theoretical basis for the engineering application of autoclaved aerated concrete low-rise and mid-rise integrated houses.
2026,
56(7):
81-89.
doi: 10.3724/j.gyjzG25031101
Abstract:
To investigate the effects of high temperature on the mechanical properties of half-grouted sleeve connections（HGSCs） under seismic loading， thirty HGSC specimens were prepared. These specimens were heated to various target temperatures and then subjected to two loading types： high-stress repeated tension-compression tests and large-deformation repeated tension-compression tests. Through tests， this study examined the failure modes， bearing capacity， and bonding characteristics of connectors under seismic loading after exposure to high temperatures. The test results indicated that under the same temperature conditions， the grout-filled sleeve connections exhibited consistent failure modes under the two loading modes. When the exposure temperature was 400 ℃ or lower， the specimens failed due to tensile fracture of the rebars at the sleeve’s external end. In contrast， when the temperature exceeded 600 ℃， the specimens failed by bond-slip at the grout-to-rebar interface. As the temperature increased， the material properties of both the rebars and the grout gradually degraded， leading to a reduction in ultimate tensile strength， bond stress， and ductility. This degradation was significantly more pronounced in specimens subjected to large-deformation repeated loading than in those under high-stress repeated loading. Finally， a formula for calculating the bond stress of HGSCs under these two cyclic loading conditions after high-temperature exposure was proposed based on statistical regression. The maximum error between the calculated results and the experimental data was within 15%.
To investigate the effects of high temperature on the mechanical properties of half-grouted sleeve connections（HGSCs） under seismic loading， thirty HGSC specimens were prepared. These specimens were heated to various target temperatures and then subjected to two loading types： high-stress repeated tension-compression tests and large-deformation repeated tension-compression tests. Through tests， this study examined the failure modes， bearing capacity， and bonding characteristics of connectors under seismic loading after exposure to high temperatures. The test results indicated that under the same temperature conditions， the grout-filled sleeve connections exhibited consistent failure modes under the two loading modes. When the exposure temperature was 400 ℃ or lower， the specimens failed due to tensile fracture of the rebars at the sleeve’s external end. In contrast， when the temperature exceeded 600 ℃， the specimens failed by bond-slip at the grout-to-rebar interface. As the temperature increased， the material properties of both the rebars and the grout gradually degraded， leading to a reduction in ultimate tensile strength， bond stress， and ductility. This degradation was significantly more pronounced in specimens subjected to large-deformation repeated loading than in those under high-stress repeated loading. Finally， a formula for calculating the bond stress of HGSCs under these two cyclic loading conditions after high-temperature exposure was proposed based on statistical regression. The maximum error between the calculated results and the experimental data was within 15%.
2026,
56(7):
90-100.
doi: 10.3724/j.gyjzG25032701
Abstract:
In order to further explore the connection form and mechanical properties of non-welded high-strength steel columns， numerical simulations and theoretical analysis of the compressive performance of bolted high-strength angle steel spliced columns were carried out based on experimental studies. First， finite element modeling and verification of the specimens were performed using ABAQUS. Then， 48 extended models were established to investigate the effects of the height-thickness ratio of the angle steel web， the width-thickness ratio of the angle steel flange， and the thickness of the middle plate on the compressive performance of high-strength angle steel spliced columns. Finally， the applicability of existing Chinese and international design specifications was evaluated， and modifications were proposed for the more conservative design specifications. The results showed that all four parameters had a positive effect on the bearing capacity of high-strength angle steel spliced columns， with the width-thickness ratio of the angle steel flange being the most influential parameter. The smaller the slenderness ratio， the greater the influence of the width-thickness ratio of the flange. The modified design formula provided a more accurate prediction of the bearing capacity of high-strength angle steel spliced columns.
In order to further explore the connection form and mechanical properties of non-welded high-strength steel columns， numerical simulations and theoretical analysis of the compressive performance of bolted high-strength angle steel spliced columns were carried out based on experimental studies. First， finite element modeling and verification of the specimens were performed using ABAQUS. Then， 48 extended models were established to investigate the effects of the height-thickness ratio of the angle steel web， the width-thickness ratio of the angle steel flange， and the thickness of the middle plate on the compressive performance of high-strength angle steel spliced columns. Finally， the applicability of existing Chinese and international design specifications was evaluated， and modifications were proposed for the more conservative design specifications. The results showed that all four parameters had a positive effect on the bearing capacity of high-strength angle steel spliced columns， with the width-thickness ratio of the angle steel flange being the most influential parameter. The smaller the slenderness ratio， the greater the influence of the width-thickness ratio of the flange. The modified design formula provided a more accurate prediction of the bearing capacity of high-strength angle steel spliced columns.
2026,
56(7):
101-111.
doi: 10.3724/j.gyjzG25030302
Abstract:
Modular construction is a novel building form in which factory-integrated three-dimensional modules are connected into an integrated whole on-site. At the current stage， the structural forms adopted in modular construction， such as stacked box structures and embedded modular structures， have certain limitations in practical application. Therefore， an innovative modular construction system based on a sparse steel frame is proposed. However， the structural frame of this innovative modular construction features large slenderness ratios of columns and long spans of beams， which may impact its economic efficiency and practical applicability for high-rise building applications. Aiming at the above-mentioned problems of the innovative modular construction， this paper proposed an equivalent modeling method that can reflect the stiffness contribution of individual modules. Parametric analysis was carried out to investigate the influence of modular stiffness contribution on the overall structural responses. Subsequently， structural optimization design based on modular stiffness contribution was conducted， and the effectiveness of the optimization was evaluated. The results showed that the inter-storey lateral stiffness of the overall structure could be improved and the reserve bearing capacity of components in the sparse steel frame could be enhanced when the modular stiffness contribution was considered in structural analysis. On the premise of ensuring the overall structural performance， the steel consumption per unit area of the sparse steel frame was effectively reduced compared with the unoptimized reference models when the modular stiffness contribution was taken into account.
Modular construction is a novel building form in which factory-integrated three-dimensional modules are connected into an integrated whole on-site. At the current stage， the structural forms adopted in modular construction， such as stacked box structures and embedded modular structures， have certain limitations in practical application. Therefore， an innovative modular construction system based on a sparse steel frame is proposed. However， the structural frame of this innovative modular construction features large slenderness ratios of columns and long spans of beams， which may impact its economic efficiency and practical applicability for high-rise building applications. Aiming at the above-mentioned problems of the innovative modular construction， this paper proposed an equivalent modeling method that can reflect the stiffness contribution of individual modules. Parametric analysis was carried out to investigate the influence of modular stiffness contribution on the overall structural responses. Subsequently， structural optimization design based on modular stiffness contribution was conducted， and the effectiveness of the optimization was evaluated. The results showed that the inter-storey lateral stiffness of the overall structure could be improved and the reserve bearing capacity of components in the sparse steel frame could be enhanced when the modular stiffness contribution was considered in structural analysis. On the premise of ensuring the overall structural performance， the steel consumption per unit area of the sparse steel frame was effectively reduced compared with the unoptimized reference models when the modular stiffness contribution was taken into account.
2026,
56(7):
112-121.
doi: 10.3724/j.gyjzG25010606
Abstract:
The friction energy-dissipating column base， as a novel form of seismic construction in steel structures， has a significant impact on the mechanical properties of structures. To investigate its flexural performance， five such column base specimens were analyzed under monotonic horizontal loading using the finite element software ABAQUS. The study examined the flexural performance， the composition of the flexural capacity， and the calculation methods for these column bases. A theoretical formula for predicting the flexural capacity of friction energy-dissipating column bases was proposed. The variation in bearing capacity under monotonic horizontal displacement loading was analyzed and compared with the theoretical formula for verification. The results showed that under monotonic horizontal loading， all column base models exhibited semi-rigid behavior， with damage primarily distributed in secondary components. This allowed the column base to fully utilize its frictional performance， thereby reducing damage to the main structure. The unified theoretical formula for the flexural capacity of friction energy-dissipating column bases can accurately predict the flexural capacity of the five types of column bases， providing a valuable reference for their application in practical engineering.
The friction energy-dissipating column base， as a novel form of seismic construction in steel structures， has a significant impact on the mechanical properties of structures. To investigate its flexural performance， five such column base specimens were analyzed under monotonic horizontal loading using the finite element software ABAQUS. The study examined the flexural performance， the composition of the flexural capacity， and the calculation methods for these column bases. A theoretical formula for predicting the flexural capacity of friction energy-dissipating column bases was proposed. The variation in bearing capacity under monotonic horizontal displacement loading was analyzed and compared with the theoretical formula for verification. The results showed that under monotonic horizontal loading， all column base models exhibited semi-rigid behavior， with damage primarily distributed in secondary components. This allowed the column base to fully utilize its frictional performance， thereby reducing damage to the main structure. The unified theoretical formula for the flexural capacity of friction energy-dissipating column bases can accurately predict the flexural capacity of the five types of column bases， providing a valuable reference for their application in practical engineering.
2026,
56(7):
122-130.
doi: 10.3724/j.gyjzG24122601
Abstract:
The deformation monitoring data of track-steel composite structures， collected in complex construction environments， are often contaminated by strong noise from various excitation sources such as equipment vibration， soil disturbance， and load variation. This noise obscures the underlying trends in the deformation time-series data， leading to low prediction accuracy with traditional models. To address this issue， this study proposes a novel deformation prediction method based on SVMD-BiLSTM-BO. First， Sequential Variational Mode Decomposition （SVMD） is applied to decompose the data into modal components. The Pearson correlation coefficient is then used to identify trend changes in the historical data， effectively suppressing the impact of noise. Since the traditional Bidirectional Long Short-Term Memory （BiLSTM） network is prone to falling into local optima due to its hyperparameter sensitivity， Bayesian Optimization （BO） is introduced to optimize these hyperparameters， enabling the model to accurately capture the deformation trends of the track. Experimental results showed that the proposed SVMD-BiLSTM-BO model outperformed the benchmark models in prediction accuracy. The absolute errors of deformation in the horizontal， vertical， and settlement directions were 0.0567 mm， 0.0899 mm， and 0.0445 mm， respectively. Furthermore， the model demonstrated a certain level of generalization capability in cross-point prediction tasks， confirming its accuracy and effectiveness in predicting railway track deformation.
The deformation monitoring data of track-steel composite structures， collected in complex construction environments， are often contaminated by strong noise from various excitation sources such as equipment vibration， soil disturbance， and load variation. This noise obscures the underlying trends in the deformation time-series data， leading to low prediction accuracy with traditional models. To address this issue， this study proposes a novel deformation prediction method based on SVMD-BiLSTM-BO. First， Sequential Variational Mode Decomposition （SVMD） is applied to decompose the data into modal components. The Pearson correlation coefficient is then used to identify trend changes in the historical data， effectively suppressing the impact of noise. Since the traditional Bidirectional Long Short-Term Memory （BiLSTM） network is prone to falling into local optima due to its hyperparameter sensitivity， Bayesian Optimization （BO） is introduced to optimize these hyperparameters， enabling the model to accurately capture the deformation trends of the track. Experimental results showed that the proposed SVMD-BiLSTM-BO model outperformed the benchmark models in prediction accuracy. The absolute errors of deformation in the horizontal， vertical， and settlement directions were 0.0567 mm， 0.0899 mm， and 0.0445 mm， respectively. Furthermore， the model demonstrated a certain level of generalization capability in cross-point prediction tasks， confirming its accuracy and effectiveness in predicting railway track deformation.
2026,
56(7):
131-139.
doi: 10.3724/j.gyjzG25082601
Abstract:
In order to optimize the axial compressive performance of special-shaped columns， a novel concrete-filled steel tubular column with T-shaped steel profiles is proposed. In this study， six specimens were designed， and axial compression tests and finite element simulations were used to systematically investigate the synergistic effects of the outer steel tube wall thickness， the built-in composite steel profile， and the core concrete. The influence of the steel ratio （ρ） and the confinement coefficient （θ） on the mechanical properties of the components were mainly examined. The results indicated that when the steel ratio ρ increased from 35.95% to 58.87%， the ultimate bearing capacity increased by 21.6%； when the confinement coefficient θ increased from 66.81% to 104.90%， the bearing capacity increased by 25.66%. The specimens exhibited mono-symmetry outward-bulging failure mode， which was dominated by local buckling. The finite element model accurately simulated this failure mode and the three-stage characteristics of the load-displacement curve. Based on comprehensive experimental， simulation and theoretical results， a relative error analysis was conducted. The average relative error between finite element simulation results and measured values was 1.81%， whereas the average relative error of the improved theoretical calculation method was 5.61%， which verifies the effectiveness of finite element analysis and the improved theoretical calculation method.
In order to optimize the axial compressive performance of special-shaped columns， a novel concrete-filled steel tubular column with T-shaped steel profiles is proposed. In this study， six specimens were designed， and axial compression tests and finite element simulations were used to systematically investigate the synergistic effects of the outer steel tube wall thickness， the built-in composite steel profile， and the core concrete. The influence of the steel ratio （ρ） and the confinement coefficient （θ） on the mechanical properties of the components were mainly examined. The results indicated that when the steel ratio ρ increased from 35.95% to 58.87%， the ultimate bearing capacity increased by 21.6%； when the confinement coefficient θ increased from 66.81% to 104.90%， the bearing capacity increased by 25.66%. The specimens exhibited mono-symmetry outward-bulging failure mode， which was dominated by local buckling. The finite element model accurately simulated this failure mode and the three-stage characteristics of the load-displacement curve. Based on comprehensive experimental， simulation and theoretical results， a relative error analysis was conducted. The average relative error between finite element simulation results and measured values was 1.81%， whereas the average relative error of the improved theoretical calculation method was 5.61%， which verifies the effectiveness of finite element analysis and the improved theoretical calculation method.
2026,
56(7):
140-145.
doi: 10.3724/j.gyjzG25021303
Abstract:
With increasing demands for crossing capacity and line clearance， the height of long-span transmission towers has risen accordingly. Concrete-filled steel tubular （CFST） structures， which offer advantages such as high bearing capacity， good ductility， strong seismic performance， and ease of construction， are being gradually adopted in the design of long-span transmission towers. Based on the super-high tower used in the 500 kV Fengcheng—Meili project， this study compares calculation results obtained from different finite element software packages and verifies the accuracy of the CFST tower model. The analytical results indicate that if the difference in tensile and compressive stiffness of CFST members is not considered， the design of the tower may be unsafe. To ensure a safe and reliable design， envelope values of internal force calculation results should be derived from both equal-stiffness and unequal-stiffness models.
With increasing demands for crossing capacity and line clearance， the height of long-span transmission towers has risen accordingly. Concrete-filled steel tubular （CFST） structures， which offer advantages such as high bearing capacity， good ductility， strong seismic performance， and ease of construction， are being gradually adopted in the design of long-span transmission towers. Based on the super-high tower used in the 500 kV Fengcheng—Meili project， this study compares calculation results obtained from different finite element software packages and verifies the accuracy of the CFST tower model. The analytical results indicate that if the difference in tensile and compressive stiffness of CFST members is not considered， the design of the tower may be unsafe. To ensure a safe and reliable design， envelope values of internal force calculation results should be derived from both equal-stiffness and unequal-stiffness models.
2026,
56(7):
146-158.
doi: 10.3724/j.gyjzG25041405
Abstract:
Vortex-induced vibrations frequently occur in ultra-high voltage （UHV） steel tubular towers， inducing fatigue damage in structural components and posing significant safety hazards， particularly given the limitations of traditional wind tunnel testing and numerical simulation method， time series induced by the vortex-induced vibrations for a typical steel tubular member from a large-span transmission tower， as a case study， VMD-SSA-Transformer-GRU has been creatively proposed to predict the vortex-induced vibration to better capture the wide-range fluctuations in vortex-induced vibration monitoring data of transmission towers. Firstly， based on the three models with different groups and iterations， the sine functions with different sample sizes have been simulated， indicating that the simulated values based on the proposed model are more accurate and have faster convergence to approach the theoretical values when compared with the five assessment indices. Furthermore， a prediction model has been proposed to predict the vortex-induced vibration， as for a single series， Mean Absolute Error （MAE）， the Mean Square Error （MSE）， the Root Mean Square Error （RMSE） and higher coefficient of determination （R2） are 0.0029653，2.6566×10-5，0.005154 and 0.96143 respectively， which indicating the reliability of the proposed model to predict the vibration with high dimensions and nonlinearity. And then， the proposed model has been considered for multi-variable series， MAE， MSE， RMSE and R2 are 0.0020449，1.7791×10-5，0.004218 and 0.97373， respectively， it can be observed that the predictions is better than that with single series， and also comparing with the frequency curves of the time series， deeply verifying the high accuracy and reliability of the multivariable VMD-SSA-Transformer-GRU model. In summary， the multivariable model can effectively capture the fluctuation of steel tubular members for a UHV transmission tower to realize the vibration prediction considering different conditions， and has obvious superiority in calculation efficiency for CFD methods.
Vortex-induced vibrations frequently occur in ultra-high voltage （UHV） steel tubular towers， inducing fatigue damage in structural components and posing significant safety hazards， particularly given the limitations of traditional wind tunnel testing and numerical simulation method， time series induced by the vortex-induced vibrations for a typical steel tubular member from a large-span transmission tower， as a case study， VMD-SSA-Transformer-GRU has been creatively proposed to predict the vortex-induced vibration to better capture the wide-range fluctuations in vortex-induced vibration monitoring data of transmission towers. Firstly， based on the three models with different groups and iterations， the sine functions with different sample sizes have been simulated， indicating that the simulated values based on the proposed model are more accurate and have faster convergence to approach the theoretical values when compared with the five assessment indices. Furthermore， a prediction model has been proposed to predict the vortex-induced vibration， as for a single series， Mean Absolute Error （MAE）， the Mean Square Error （MSE）， the Root Mean Square Error （RMSE） and higher coefficient of determination （R2） are 0.0029653，2.6566×10-5，0.005154 and 0.96143 respectively， which indicating the reliability of the proposed model to predict the vibration with high dimensions and nonlinearity. And then， the proposed model has been considered for multi-variable series， MAE， MSE， RMSE and R2 are 0.0020449，1.7791×10-5，0.004218 and 0.97373， respectively， it can be observed that the predictions is better than that with single series， and also comparing with the frequency curves of the time series， deeply verifying the high accuracy and reliability of the multivariable VMD-SSA-Transformer-GRU model. In summary， the multivariable model can effectively capture the fluctuation of steel tubular members for a UHV transmission tower to realize the vibration prediction considering different conditions， and has obvious superiority in calculation efficiency for CFD methods.
2026,
56(7):
159-170.
doi: 10.3724/j.gyjzG24090307
Abstract:
When extreme fires occur in steel bridges in ambient wind field， wind speed influences the fire development process. The study of the fire temperature field and structural response of steel bridges under the effect of multi-hazard coupling， considering the influence of ambient wind field， is a key problem that needs to be solved in the current research on steel bridge fire resistance. This paper calculated the maximum heat release rate of a 50 m3 tank truck fire at different wind speeds based on the background of a 30 m simply-supported steel box girder bridge and the principles of combustion and fire science， combined with FDS numerical simulation. In addition， this paper determined the fire heat release rate curve through the exponential model， analyzed the steel box girder fire temperature field under the action of different wind speeds of tank truck fire through the CFD-FEM coupling method. Finally， it determined the fire resistance limit of the steel bridge under the action of fire through thermal-structure coupling analysis. The analysis showed that when the average wind speed increased from 4.20 m /s to 9.86 m /s， the maximum heat release rate of a 50 m3 tank truck fire increased from 52.436 MW to 104.636 MW with increasing wind speed， and its increment gradually decreased； as the wind speed increased， the fire burning time was reduced to approximately 50% of the original， the flame height gradually decreased and tended to stabilize at 6.75 m （removing the height of the tanker）， the central area of the flame gradually expanded， and the smoke flow tilted downwind. The high-temperature core area on the surface of the steel box girder under the action of a tank truck fire gradually migrated and expanded downwind with the increase of wind speed， and the highest temperature of the steel box girder under different wind speed conditions varied from 600 ℃ to 730 ℃ due to heat conduction， convection， and radiation， and remained basically constant when subjected to fire for about 30-40 min； the mid-span deflection of the main girder under fire conditions at different wind speeds exceeded the limit value. When the wind speed increased from 4.20 m/s to 9.86 m/s， the fire resistance time of the main girder was shortened from 25.7 min to 13.3 min， representing a a reduction of approximately 50%. The steel box girder ultimately failed due to excessive deformation.
When extreme fires occur in steel bridges in ambient wind field， wind speed influences the fire development process. The study of the fire temperature field and structural response of steel bridges under the effect of multi-hazard coupling， considering the influence of ambient wind field， is a key problem that needs to be solved in the current research on steel bridge fire resistance. This paper calculated the maximum heat release rate of a 50 m3 tank truck fire at different wind speeds based on the background of a 30 m simply-supported steel box girder bridge and the principles of combustion and fire science， combined with FDS numerical simulation. In addition， this paper determined the fire heat release rate curve through the exponential model， analyzed the steel box girder fire temperature field under the action of different wind speeds of tank truck fire through the CFD-FEM coupling method. Finally， it determined the fire resistance limit of the steel bridge under the action of fire through thermal-structure coupling analysis. The analysis showed that when the average wind speed increased from 4.20 m /s to 9.86 m /s， the maximum heat release rate of a 50 m3 tank truck fire increased from 52.436 MW to 104.636 MW with increasing wind speed， and its increment gradually decreased； as the wind speed increased， the fire burning time was reduced to approximately 50% of the original， the flame height gradually decreased and tended to stabilize at 6.75 m （removing the height of the tanker）， the central area of the flame gradually expanded， and the smoke flow tilted downwind. The high-temperature core area on the surface of the steel box girder under the action of a tank truck fire gradually migrated and expanded downwind with the increase of wind speed， and the highest temperature of the steel box girder under different wind speed conditions varied from 600 ℃ to 730 ℃ due to heat conduction， convection， and radiation， and remained basically constant when subjected to fire for about 30-40 min； the mid-span deflection of the main girder under fire conditions at different wind speeds exceeded the limit value. When the wind speed increased from 4.20 m/s to 9.86 m/s， the fire resistance time of the main girder was shortened from 25.7 min to 13.3 min， representing a a reduction of approximately 50%. The steel box girder ultimately failed due to excessive deformation.
2026,
56(7):
171-177.
doi: 10.3724/j.gyjzG24121501
Abstract:
As a relatively novel structural form， the super high-rise inclined suspension structure can flexiblly adjust the inclination angle and suspension method according to the requirements of building functions and appearance. However， its construction process is complex and poses significant challenges. Taking the South China headquarters project of Sany Heavy Industry Co. ， Ltd. as an example， a novel construction method known as the temporary support-free reverse construction method is proposed for super high-rise inclined suspension structure through the comparison and selection of different construction schemes. This method involves first installation the inclined columns of the outer frame and the joint layer structure， then lifting the hanging columns and temporarily fixing it in its inclined position using measures such as chain blocks. next， the suspension layer structure is installed from the bottom to top to achieve temporary support-free installation. Compared with the conventional approaches， namely the temporary-supported sequential construction method and the temporary-supported reverse construction method， although this method has relatively high technical difficulty， it does not require the temporary supports， and has advantages in safety， cost and construction period. On this basis， the construction process of the proposed method was simulated and analyzed to ensure the construction safety and reliability， providing a reference for the construction of similar projects.
As a relatively novel structural form， the super high-rise inclined suspension structure can flexiblly adjust the inclination angle and suspension method according to the requirements of building functions and appearance. However， its construction process is complex and poses significant challenges. Taking the South China headquarters project of Sany Heavy Industry Co. ， Ltd. as an example， a novel construction method known as the temporary support-free reverse construction method is proposed for super high-rise inclined suspension structure through the comparison and selection of different construction schemes. This method involves first installation the inclined columns of the outer frame and the joint layer structure， then lifting the hanging columns and temporarily fixing it in its inclined position using measures such as chain blocks. next， the suspension layer structure is installed from the bottom to top to achieve temporary support-free installation. Compared with the conventional approaches， namely the temporary-supported sequential construction method and the temporary-supported reverse construction method， although this method has relatively high technical difficulty， it does not require the temporary supports， and has advantages in safety， cost and construction period. On this basis， the construction process of the proposed method was simulated and analyzed to ensure the construction safety and reliability， providing a reference for the construction of similar projects.
2026,
56(7):
178-186.
doi: 10.3724/j.gyjzG25061502
Abstract:
Rubber particles from crushed waste tires mixed with soil can improve the engineering properties of soil. In order to improve the utilization rate of waste tires and solve the engineering problems of expansive soils， this study took the expansive soil in the Jiutai area of Jilin Province as the research object. Freezing and swelling tests of modified expansive soil under different factors （water content， particle size， and mix proportion） were carried out in a closed system to investigate the effects of freezing and swelling， temperature change， and moisture migration on modified expansive soil. This paper analyzed the coupling effects of rubber particle dosage， rubber particle size， and water content. The test results showed that the deformation of expanded soil was closely related to initial water content， rubber particle dosage， and rubber particle size： specimens with low water content and small rubber particle size exhibited frost contraction， while those with high water content and large rubber particle size showed frost expansion. An appropriate amount of rubber particle dosage could suppress both the frost expansion and frost contraction of the soil samples. The distribution of the final water content of the expansive soil along the depth direction was characterized as follows： water content in the frozen area increased， water accumulated in the freezing front， and water content in the unfrozen area decreased.
Rubber particles from crushed waste tires mixed with soil can improve the engineering properties of soil. In order to improve the utilization rate of waste tires and solve the engineering problems of expansive soils， this study took the expansive soil in the Jiutai area of Jilin Province as the research object. Freezing and swelling tests of modified expansive soil under different factors （water content， particle size， and mix proportion） were carried out in a closed system to investigate the effects of freezing and swelling， temperature change， and moisture migration on modified expansive soil. This paper analyzed the coupling effects of rubber particle dosage， rubber particle size， and water content. The test results showed that the deformation of expanded soil was closely related to initial water content， rubber particle dosage， and rubber particle size： specimens with low water content and small rubber particle size exhibited frost contraction， while those with high water content and large rubber particle size showed frost expansion. An appropriate amount of rubber particle dosage could suppress both the frost expansion and frost contraction of the soil samples. The distribution of the final water content of the expansive soil along the depth direction was characterized as follows： water content in the frozen area increased， water accumulated in the freezing front， and water content in the unfrozen area decreased.
2026,
56(7):
187-198.
doi: 10.3724/j.gyjzG25080103
Abstract:
This study systematically investigated the effectiveness of chemical reduction combined with microbial mineralization in remediating Cr（Ⅵ）-contaminated soil. The remediation performance was evaluated under varying cementation solution concentrations and curing ages using unconfined compressive strength tests and toxicity leaching experiments. Microstructural analysis was employed to elucidate the remediation mechanisms at the microscale， providing new theoretical foundations for the remediation of Cr（Ⅵ）-contaminated soil. The results demonstrated that the integrated chemical-microbial reduction-mineralization technology effectively remediated Cr（Ⅵ）-contaminated soil， achieving a compressive strength of 0.227 MPa in the solidified soil and reducing the Cr（Ⅵ） leaching concentration， with a removal efficiency exceeding 96%. Post-treatment analysis revealed that soil pH presented an initial decrease followed by a rise， and electrical conductivity exhibited a marked upward trend， which were primarily driven by urea hydrolysis reactions. Carbonate crystal formation was observed in treated samples， and X-ray diffraction and energy-dispersive spectroscopy （EDS） confirmed that hexavalent and trivalent chromium contaminants were immobilized through surface adsorption or lattice solid-solution mechanisms. Notably， Cr（Ⅲ） predominantly entered the calcite crystal structure through isomorphous substitution， forming stable calcium-chromium coprecipitates （Ca10Cr6O24（CO3）） characterized by low mobility and bioavailability.
This study systematically investigated the effectiveness of chemical reduction combined with microbial mineralization in remediating Cr（Ⅵ）-contaminated soil. The remediation performance was evaluated under varying cementation solution concentrations and curing ages using unconfined compressive strength tests and toxicity leaching experiments. Microstructural analysis was employed to elucidate the remediation mechanisms at the microscale， providing new theoretical foundations for the remediation of Cr（Ⅵ）-contaminated soil. The results demonstrated that the integrated chemical-microbial reduction-mineralization technology effectively remediated Cr（Ⅵ）-contaminated soil， achieving a compressive strength of 0.227 MPa in the solidified soil and reducing the Cr（Ⅵ） leaching concentration， with a removal efficiency exceeding 96%. Post-treatment analysis revealed that soil pH presented an initial decrease followed by a rise， and electrical conductivity exhibited a marked upward trend， which were primarily driven by urea hydrolysis reactions. Carbonate crystal formation was observed in treated samples， and X-ray diffraction and energy-dispersive spectroscopy （EDS） confirmed that hexavalent and trivalent chromium contaminants were immobilized through surface adsorption or lattice solid-solution mechanisms. Notably， Cr（Ⅲ） predominantly entered the calcite crystal structure through isomorphous substitution， forming stable calcium-chromium coprecipitates （Ca10Cr6O24（CO3）） characterized by low mobility and bioavailability.
2026,
56(7):
199-208.
doi: 10.3724/j.gyjzG25021902
Abstract:
The microparticle characteristics and physical and mechanical properties of medium sand vary significantly with deposition depth. Studying how these micromechanical characteristics influence cofferdam stability in sand layers can provide valuable insights for foundation pit design and safety assessment. Taking a bridge foundation cofferdam project in the Wei River medium sand formation in Xi’an as an example， this study investigated the microstructural and mechanical characteristics of Wei River medium sand through direct shear tests， permeability tests， and SEM tests. Meanwhile， a foundation pit construction model for the medium sand stratum was established using FLAC3D software to systematically analyze the influence of sand particle length-to-width ratio， roundness， and roughness on internal friction angle， permeability coefficient， and cofferdam stability deformation. The results showed that： 1） the sand grains of the Wei River medium sand were irregular in shape with non-smooth surfaces； particle length was mainly distributed between 0.1 mm and 0.3 mm， and the width was mainly distributed from 0 to 0.2 mm. 2） As the length-to-width ratio and roughness of the medium sand increased， the internal friction angle gradually increased while permeability gradually decreased； conversely， with an increase in roundness， the internal friction angle gradually decreased and the permeability gradually increased. 3） The horizontal displacement of the cofferdam decreased with increasing length-to-width ratio and roughness of the medium sand， but increased with increasing roundness. This study revealed the relationship between the microstructure of Wei River sand and its physical and mechanical properties， aiming to provide a scientific basis for the design of foundation pit cofferdams in similar projects.
The microparticle characteristics and physical and mechanical properties of medium sand vary significantly with deposition depth. Studying how these micromechanical characteristics influence cofferdam stability in sand layers can provide valuable insights for foundation pit design and safety assessment. Taking a bridge foundation cofferdam project in the Wei River medium sand formation in Xi’an as an example， this study investigated the microstructural and mechanical characteristics of Wei River medium sand through direct shear tests， permeability tests， and SEM tests. Meanwhile， a foundation pit construction model for the medium sand stratum was established using FLAC3D software to systematically analyze the influence of sand particle length-to-width ratio， roundness， and roughness on internal friction angle， permeability coefficient， and cofferdam stability deformation. The results showed that： 1） the sand grains of the Wei River medium sand were irregular in shape with non-smooth surfaces； particle length was mainly distributed between 0.1 mm and 0.3 mm， and the width was mainly distributed from 0 to 0.2 mm. 2） As the length-to-width ratio and roughness of the medium sand increased， the internal friction angle gradually increased while permeability gradually decreased； conversely， with an increase in roundness， the internal friction angle gradually decreased and the permeability gradually increased. 3） The horizontal displacement of the cofferdam decreased with increasing length-to-width ratio and roughness of the medium sand， but increased with increasing roundness. This study revealed the relationship between the microstructure of Wei River sand and its physical and mechanical properties， aiming to provide a scientific basis for the design of foundation pit cofferdams in similar projects.
2026,
56(7):
209-215.
doi: 10.3724/j.gyjzG24122401
Abstract:
This paper proposes a method for calculating the compressive bearing capacity of inclined piles based on the limit state design theory. The theoretical formula for calculating the compressive bearing capacity of inclined piles is derived using the deflection theory of elastic foundation beams. Theoretical derivation demonstrates that the theoretical compressive bearing capacity of inclined piles can be determined by plotting the N-M curve of the pile bearing capacity. Based on the static load test data from four actual engineering projects， the effectiveness and parameter values of the theoretical formula were calculated and verified. The comparison results showed that the theoretical formula can accurately predict the compressive bearing capacity of inclined piles. This formula can be used to evaluate the compressive bearing capacity of inclined piles based on static load test data.
This paper proposes a method for calculating the compressive bearing capacity of inclined piles based on the limit state design theory. The theoretical formula for calculating the compressive bearing capacity of inclined piles is derived using the deflection theory of elastic foundation beams. Theoretical derivation demonstrates that the theoretical compressive bearing capacity of inclined piles can be determined by plotting the N-M curve of the pile bearing capacity. Based on the static load test data from four actual engineering projects， the effectiveness and parameter values of the theoretical formula were calculated and verified. The comparison results showed that the theoretical formula can accurately predict the compressive bearing capacity of inclined piles. This formula can be used to evaluate the compressive bearing capacity of inclined piles based on static load test data.
2026,
56(7):
216-222.
doi: 10.3724/j.gyjzG24123001
Abstract:
Based on the foundation excavation project of a metro station on Nanjing Metro Line 11， this study proposes an intelligent dynamic prediction model for diaphragm wall deformation using an autoregressive approach to achieve high-precision predictions for multiple future time steps. The model integrates Long Short-Term Memory （LSTM） networks and Convolutional Neural Networks （CNN）， leveraging their complementary strengths in extracting spatiotemporal features. Furthermore， the Grey Wolf Optimizer （GWO） was employed to optimize the model’s hyperparameters， thereby enhancing its prediction performance and stability. The results demonstrated that GWO significantly improved the accuracy of the fusion model in multi-step prediction tasks， verifying the applicability and reliability of the proposed method in complex engineering environments.
Based on the foundation excavation project of a metro station on Nanjing Metro Line 11， this study proposes an intelligent dynamic prediction model for diaphragm wall deformation using an autoregressive approach to achieve high-precision predictions for multiple future time steps. The model integrates Long Short-Term Memory （LSTM） networks and Convolutional Neural Networks （CNN）， leveraging their complementary strengths in extracting spatiotemporal features. Furthermore， the Grey Wolf Optimizer （GWO） was employed to optimize the model’s hyperparameters， thereby enhancing its prediction performance and stability. The results demonstrated that GWO significantly improved the accuracy of the fusion model in multi-step prediction tasks， verifying the applicability and reliability of the proposed method in complex engineering environments.
2026,
56(7):
223-234.
doi: 10.3724/j.gyjzG24122101
Abstract:
The deformation and stress characteristics of foundation pit support structures are crucial indicators for assessing pit stability and safety. This study examined the internal forces and deformation of the support system during the simultaneous excavation and superstructure construction at the Guangzhou Xintang Metro Station deep excavation project. Through field monitoring and dynamic simulation， the mechanical responses of internal bracing， diaphragm walls， and slab covers to combined loads from superstructure construction， train operation， and earth excavation unloading were analyzed， and the pit’s overall deformation patterns were investigated. The results demonstrated that an “M”-shaped load pattern for simulating train dynamics better reflected real conditions compared to previous sinusoidal wave models， with simulations closely aligning with field measurements. Monitoring data analysis revealed three patterns in the horizontal displacement of the pile bodies： “forward-leaning”， “hill-type”， and “spindle-shaped”. Due to the transition in the support systems at the junction between the open-cut and cover-cut excavation sections， stress concentration occurred. Furthermore， the complex construction conditions of this project caused the location of stress concentration to shift between the corners of the pit and the midsections of the diaphragm walls.
The deformation and stress characteristics of foundation pit support structures are crucial indicators for assessing pit stability and safety. This study examined the internal forces and deformation of the support system during the simultaneous excavation and superstructure construction at the Guangzhou Xintang Metro Station deep excavation project. Through field monitoring and dynamic simulation， the mechanical responses of internal bracing， diaphragm walls， and slab covers to combined loads from superstructure construction， train operation， and earth excavation unloading were analyzed， and the pit’s overall deformation patterns were investigated. The results demonstrated that an “M”-shaped load pattern for simulating train dynamics better reflected real conditions compared to previous sinusoidal wave models， with simulations closely aligning with field measurements. Monitoring data analysis revealed three patterns in the horizontal displacement of the pile bodies： “forward-leaning”， “hill-type”， and “spindle-shaped”. Due to the transition in the support systems at the junction between the open-cut and cover-cut excavation sections， stress concentration occurred. Furthermore， the complex construction conditions of this project caused the location of stress concentration to shift between the corners of the pit and the midsections of the diaphragm walls.
2026,
56(7):
235-242.
doi: 10.3724/j.gyjzG25062508
Abstract:
Uneven settlement of soft soil foundations poses a potential threat to buried pipelines. Due to their low flexural stiffness， flexible pipelines are particularly prone to deformation and damage during such settlement. Through model tests of flexible pipelines in soft soil foundations under uneven settlement， this paper analyzed the variations in soil pressure and the mechanical characteristics of the pipelines. It further investigated the influence of pipe diameter and burial depth on the mechanical response of flexible pipelines. The results showed that after six cycles of uneven settlement， the soil pressure on the top of the pipeline increased significantly， with the soil pressure on the side of the pipeline reaching the largest. The soil pressure coefficient also increased with the number of settlement cycles. A nonlinear expression was established， relating the soil pressure coefficient to both the settlement depth and range， which can provide a theoretical basis for evaluating the mechanical response of flexible pipelines under uneven settlement. Both axial and circumferential stresses， as well as the displacements of the pipeline， increased with the expansion of the settlement range and the increase in the settlement magnitude. Increasing the pipe diameter or reducing the burial depth can effectively reduce pipeline stress and displacement. Therefore， in engineering design， the combined influence of both pipe diameter and burial depth should be comprehensively considered.
Uneven settlement of soft soil foundations poses a potential threat to buried pipelines. Due to their low flexural stiffness， flexible pipelines are particularly prone to deformation and damage during such settlement. Through model tests of flexible pipelines in soft soil foundations under uneven settlement， this paper analyzed the variations in soil pressure and the mechanical characteristics of the pipelines. It further investigated the influence of pipe diameter and burial depth on the mechanical response of flexible pipelines. The results showed that after six cycles of uneven settlement， the soil pressure on the top of the pipeline increased significantly， with the soil pressure on the side of the pipeline reaching the largest. The soil pressure coefficient also increased with the number of settlement cycles. A nonlinear expression was established， relating the soil pressure coefficient to both the settlement depth and range， which can provide a theoretical basis for evaluating the mechanical response of flexible pipelines under uneven settlement. Both axial and circumferential stresses， as well as the displacements of the pipeline， increased with the expansion of the settlement range and the increase in the settlement magnitude. Increasing the pipe diameter or reducing the burial depth can effectively reduce pipeline stress and displacement. Therefore， in engineering design， the combined influence of both pipe diameter and burial depth should be comprehensively considered.
2026,
56(7):
243-252.
doi: 10.3724/j.gyjzG25060702
Abstract:
Helical anchors are widely employed in marine engineering， transmission line foundations， and wind turbine installations due to their advantages of minimized soil disturbance， reduced environmental footprint， and superior uplift resistance. To resolve significant inconsistencies and applicability limitations in existing theoretical models for uplift capacity prediction， this investigation combined systematic laboratory model testing with advanced numerical simulations to elucidate the uplift bearing characteristics and failure mechanisms of helical anchors in sandy soils. The uplift capacity coefficient （Nq） and lateral pressure coefficient （Ku） for varied sand states were empirically calibrated using the Chinese Technical Code for Transmission Line Foundation Design （DL/T 5219-2023）. Critical findings demonstrated that： 1） the Modified Mohr-Coulomb （MMC） constitutive model achieved >10% higher accuracy than the conventional Mohr-Coulomb （MC） model； 2） progressive soil strain-softening， governed by circumferential stress redistribution around the anchor periphery， intensified with embedment ratio （H/D）； 3） load distribution exhibited plate-spacing dependency， transitioning from 30%/70% （bottom/top plate） at 1D spacing to 20%/80% at 2D spacing； 4） at H/D > 4， single-helix anchors developed localized failure， while multi-helix systems exhibited a hybrid “conical shear-independent” failure mode； 5） uplift capacity growth featured a distinct inflection point at H/D = 5-6， with rapid enhancement in shallow embedments （H/D < 5-6） and progressive attenuation in deep embedments （H/D > 5-6）， establishing 5-6 as the critical embedment ratio for sandy soils； 6） parametrically calibrated Nq and Ku coefficients enabled high-accuracy uplift capacity predictions， providing a validated theoretical framework for helical anchor design in geotechnical practice.
Helical anchors are widely employed in marine engineering， transmission line foundations， and wind turbine installations due to their advantages of minimized soil disturbance， reduced environmental footprint， and superior uplift resistance. To resolve significant inconsistencies and applicability limitations in existing theoretical models for uplift capacity prediction， this investigation combined systematic laboratory model testing with advanced numerical simulations to elucidate the uplift bearing characteristics and failure mechanisms of helical anchors in sandy soils. The uplift capacity coefficient （Nq） and lateral pressure coefficient （Ku） for varied sand states were empirically calibrated using the Chinese Technical Code for Transmission Line Foundation Design （DL/T 5219-2023）. Critical findings demonstrated that： 1） the Modified Mohr-Coulomb （MMC） constitutive model achieved >10% higher accuracy than the conventional Mohr-Coulomb （MC） model； 2） progressive soil strain-softening， governed by circumferential stress redistribution around the anchor periphery， intensified with embedment ratio （H/D）； 3） load distribution exhibited plate-spacing dependency， transitioning from 30%/70% （bottom/top plate） at 1D spacing to 20%/80% at 2D spacing； 4） at H/D > 4， single-helix anchors developed localized failure， while multi-helix systems exhibited a hybrid “conical shear-independent” failure mode； 5） uplift capacity growth featured a distinct inflection point at H/D = 5-6， with rapid enhancement in shallow embedments （H/D < 5-6） and progressive attenuation in deep embedments （H/D > 5-6）， establishing 5-6 as the critical embedment ratio for sandy soils； 6） parametrically calibrated Nq and Ku coefficients enabled high-accuracy uplift capacity predictions， providing a validated theoretical framework for helical anchor design in geotechnical practice.
2026,
56(7):
253-260.
doi: 10.3724/j.gyjzG25010601
Abstract:
Ultra-high performance concrete （UHPC） incorporating ultra-high molecular weight polyester （UHMWPE） fibers is a novel high-strength composite. It exhibits high strength， high ductility， and excellent durability. This experiment investigated the mechanisms by which UHMWPE staple fibers and structural steel meshes enhance the structural performance of concrete slabs. Four rectangular thin slabs of identical geometry but with different fiber contents and steel mesh configurations were fabricated. Through tests， the stress， strain， and displacement of the specimens were monitored throughout the entire loading process until failure. The results demonstrated that the UHMWPE fibers formed a random three-dimensional network within the concrete slab. This network bridged and anchored the concrete matrix， suppressed the initiation and propagation of cracks， significantly enhanced crack resistance and ductility， and substantially improved the bearing capacity of the concrete slabs. The incorporation of the structural steel mesh provided a primary supporting skeleton. The randomly distributed short fibers connected with this skeleton， forming an integrated system. This synergy between the steel mesh and the UHMWPE fibers collectively enhanced the slabs’ bearing capacity and deformation resistance.
Ultra-high performance concrete （UHPC） incorporating ultra-high molecular weight polyester （UHMWPE） fibers is a novel high-strength composite. It exhibits high strength， high ductility， and excellent durability. This experiment investigated the mechanisms by which UHMWPE staple fibers and structural steel meshes enhance the structural performance of concrete slabs. Four rectangular thin slabs of identical geometry but with different fiber contents and steel mesh configurations were fabricated. Through tests， the stress， strain， and displacement of the specimens were monitored throughout the entire loading process until failure. The results demonstrated that the UHMWPE fibers formed a random three-dimensional network within the concrete slab. This network bridged and anchored the concrete matrix， suppressed the initiation and propagation of cracks， significantly enhanced crack resistance and ductility， and substantially improved the bearing capacity of the concrete slabs. The incorporation of the structural steel mesh provided a primary supporting skeleton. The randomly distributed short fibers connected with this skeleton， forming an integrated system. This synergy between the steel mesh and the UHMWPE fibers collectively enhanced the slabs’ bearing capacity and deformation resistance.
2026,
56(7):
261-271.
doi: 10.3724/j.gyjzG25082203
Abstract:
As a green building material that enables waste reuse， rubberized concrete has garnered significant research attention. However， its mechanical properties are adversely affected by the inherent characteristics of rubber particles， commonly resulting in issues such as reduced compressive strength and decreased elastic modulus， which limit its engineering applications. The incorporation of mineral admixtures or fiber admixtures has become an important technical approach to enhance its mechanical performance. This paper provides a systematic review of the advantages and limitations of the mechanical properties of rubberized concrete， as well as the enhancement mechanisms and effects of mineral and fiber admixtures on these properties. Research indicates that mineral admixtures， such as appropriate amounts of fly ash （FA）， silica fume （SF）， and others， primarily optimize the interfacial structure through physical filling and chemical activity， significantly enhancing the strength and elastic modulus. Among fiber admixtures， steel and basalt fibers effectively enhance compressive and splitting tensile strength， while polypropylene （PP） and polyvinyl alcohol （PVA） fibers improve toughness and crack control. Hybrid fiber systems leverage synergistic effects to achieve comprehensive performance optimization.
As a green building material that enables waste reuse， rubberized concrete has garnered significant research attention. However， its mechanical properties are adversely affected by the inherent characteristics of rubber particles， commonly resulting in issues such as reduced compressive strength and decreased elastic modulus， which limit its engineering applications. The incorporation of mineral admixtures or fiber admixtures has become an important technical approach to enhance its mechanical performance. This paper provides a systematic review of the advantages and limitations of the mechanical properties of rubberized concrete， as well as the enhancement mechanisms and effects of mineral and fiber admixtures on these properties. Research indicates that mineral admixtures， such as appropriate amounts of fly ash （FA）， silica fume （SF）， and others， primarily optimize the interfacial structure through physical filling and chemical activity， significantly enhancing the strength and elastic modulus. Among fiber admixtures， steel and basalt fibers effectively enhance compressive and splitting tensile strength， while polypropylene （PP） and polyvinyl alcohol （PVA） fibers improve toughness and crack control. Hybrid fiber systems leverage synergistic effects to achieve comprehensive performance optimization.
2026,
56(7):
272-281.
doi: 10.3724/j.gyjzG25010805
Abstract:
This study focuses on a large cantilevered high-rise structure with a height of 26.2 m， which adopts a frame-shear wall structural system. The structure exhibits three out-of-code irregularities， including torsional irregularity， discontinuous floors， and component interruption. Specific seismic performance objectives and strengthening measures were established for these irregularities. The structure was analyzed using YJK， MIDAS Building， and SAUSAGE software， conducting elastic analysis under frequent earthquakes and wind loads， equivalent elastic analysis under fortification and rare earthquakes， as well as elasto-plastic time-history analysis under rare earthquakes. Structural analyses were performed to address key irregular features， such as discontinuous floor slabs， and discontinuous members. These included stress analysis of floor slabs， performance evaluation of cantilevered skip-floor trusses， and buckling analysis of cross-story columns， supplemented with a floor comfort assessment. The calculation results demonstrates that， with appropriate strengthening measures， all structural indicators met the code requirements and achieve the predefined seismic performance objectives. The design methodology and measures adopted can serve as a reference for similar projects. The design methods and strengthening measures employed can serve as a reference for similar projects.
This study focuses on a large cantilevered high-rise structure with a height of 26.2 m， which adopts a frame-shear wall structural system. The structure exhibits three out-of-code irregularities， including torsional irregularity， discontinuous floors， and component interruption. Specific seismic performance objectives and strengthening measures were established for these irregularities. The structure was analyzed using YJK， MIDAS Building， and SAUSAGE software， conducting elastic analysis under frequent earthquakes and wind loads， equivalent elastic analysis under fortification and rare earthquakes， as well as elasto-plastic time-history analysis under rare earthquakes. Structural analyses were performed to address key irregular features， such as discontinuous floor slabs， and discontinuous members. These included stress analysis of floor slabs， performance evaluation of cantilevered skip-floor trusses， and buckling analysis of cross-story columns， supplemented with a floor comfort assessment. The calculation results demonstrates that， with appropriate strengthening measures， all structural indicators met the code requirements and achieve the predefined seismic performance objectives. The design methodology and measures adopted can serve as a reference for similar projects. The design methods and strengthening measures employed can serve as a reference for similar projects.
2026,
56(7):
282-287.
doi: 10.3724/j.gyjzG25021703
Abstract:
As a new mode of industrial space， the “industrial upstairs” concept is explored in dense urban agglomerations. This study analyzes the effects of peak acceleration on an adjacent high-precision laboratory and an adjacent biomedical laboratory caused by vehicle dynamic loads in horizontal freight corridors. The results showed that the peak acceleration increased with the number of vehicle floors. The peak acceleration generated by continuous vehicle movement was significantly greater than that from a single vehicle. Furthermore， the peak acceleration at each measurement point decreased as the distance from the vibration source increased. A vibration isolation trench was constructed between the horizontal freight corridor and the high-precision laboratory to lengthen the propagation path of vibration waves and reduce the peak acceleration at the measurement points. Compared to the scenario without a trench， the reduction in peak acceleration was insignificant when the trench depth was within 7.5 meters. However， when the trench depth increasesd from 7.5 meters to 12.5 meters， the peak acceleration decreased markedly， demonstrating an obvious vibration reduction effect. It is necessary to analyze the structural dynamic response at different trench depths to determine reasonable technical parameters for the vibration isolation trench in engineering design.
As a new mode of industrial space， the “industrial upstairs” concept is explored in dense urban agglomerations. This study analyzes the effects of peak acceleration on an adjacent high-precision laboratory and an adjacent biomedical laboratory caused by vehicle dynamic loads in horizontal freight corridors. The results showed that the peak acceleration increased with the number of vehicle floors. The peak acceleration generated by continuous vehicle movement was significantly greater than that from a single vehicle. Furthermore， the peak acceleration at each measurement point decreased as the distance from the vibration source increased. A vibration isolation trench was constructed between the horizontal freight corridor and the high-precision laboratory to lengthen the propagation path of vibration waves and reduce the peak acceleration at the measurement points. Compared to the scenario without a trench， the reduction in peak acceleration was insignificant when the trench depth was within 7.5 meters. However， when the trench depth increasesd from 7.5 meters to 12.5 meters， the peak acceleration decreased markedly， demonstrating an obvious vibration reduction effect. It is necessary to analyze the structural dynamic response at different trench depths to determine reasonable technical parameters for the vibration isolation trench in engineering design.
2026,
56(7):
288-295.
doi: 10.3724/j.gyjzG24122202
Abstract:
In BIM applications， different BIM software tools are typically used to establish models based on project characteristics. These models are then exported in either proprietary software formats or universal data formats for transfer and use in other software platforms. However， issues such as data loss and distortion may occur during the conversion process. Therefore， this paper studies and proposes a technical approach that utilizes the universal BIM data format， IFC， as the foundational data source for modeling. First， based on the modeling requirements for building engineering， an IFC component library was developed to provide component resources for the BIM modeling process. Second， key technologies in BIM modeling were studied， including spatial location assignment， geometric dimension modification， and color and material setting， and their logical mapping relationships to the IFC schema were also analyzed. Finally， an IFC schema-based BIM modeling platform was developed and tested on a building project. The results demonstrate the feasibility of this IFC-based modeling approach. As IFC component resources develop， this approach will facilitate IFC-based modeling and improve the quality and efficiency of BIM data sharing and exchange.
In BIM applications， different BIM software tools are typically used to establish models based on project characteristics. These models are then exported in either proprietary software formats or universal data formats for transfer and use in other software platforms. However， issues such as data loss and distortion may occur during the conversion process. Therefore， this paper studies and proposes a technical approach that utilizes the universal BIM data format， IFC， as the foundational data source for modeling. First， based on the modeling requirements for building engineering， an IFC component library was developed to provide component resources for the BIM modeling process. Second， key technologies in BIM modeling were studied， including spatial location assignment， geometric dimension modification， and color and material setting， and their logical mapping relationships to the IFC schema were also analyzed. Finally， an IFC schema-based BIM modeling platform was developed and tested on a building project. The results demonstrate the feasibility of this IFC-based modeling approach. As IFC component resources develop， this approach will facilitate IFC-based modeling and improve the quality and efficiency of BIM data sharing and exchange.
2026,
56(7):
296-306.
doi: 10.3724/j.gyjzG26032902
Abstract:
Traditional monitoring platforms suffer from several critical limitations， including poor adaptability， non-standardized data formats， and insufficient mining and analysis of operational data. To address these issues， this paper proposes a structural monitoring platform architecture that features strong adaptability， rapid development support， and low-cost deployment. Adopting a standardized design approach， this paper elaborates on the implementation paths of key technologies， including data ingestion and cleaning， multidimensional data analysis， AI-assisted trend recognition， and the comparison and selection of lightweight 3D rendering engines. Practical application in a national-level cultural heritage monitoring project demonstrates that the proposed platform architecture can achieve real-time monitoring， intelligent analysis， and visual interaction in complex building scenarios.
Traditional monitoring platforms suffer from several critical limitations， including poor adaptability， non-standardized data formats， and insufficient mining and analysis of operational data. To address these issues， this paper proposes a structural monitoring platform architecture that features strong adaptability， rapid development support， and low-cost deployment. Adopting a standardized design approach， this paper elaborates on the implementation paths of key technologies， including data ingestion and cleaning， multidimensional data analysis， AI-assisted trend recognition， and the comparison and selection of lightweight 3D rendering engines. Practical application in a national-level cultural heritage monitoring project demonstrates that the proposed platform architecture can achieve real-time monitoring， intelligent analysis， and visual interaction in complex building scenarios.
