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2024 Vol. 54, No. 1
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2024, 54(1): 1-10.
doi: 10.3724/j.gyjzG23071809
Abstract:
The acceleration of urbanization has led to a sharp rise in the number of super high-rise buildings in China. However, the issues related to the operation and maintenance of those buildings have become increasingly prominent. As a result, extensive attention to the service safety of super high-rise buildings have been paid. Summarizing and analyzing the theoretical methods and practical applications of identifying dynamic characteristic parameters of super high-rise buildings, the characteristics of super high-rise building structure monitoring technique, which were represented by the time domain, frequency domain, time-frequency domain and the new modal recognition method. Subsequently, the advantages and limitations of each monitoring method and system were compared. Simultaneously, the main issues in the current monitoring technique for super high-rise buildings were summed and development trends of monitoring methods were discussed. Eventually, the application of dynamic characteristic identification in the monitoring of super high-rise buildings was sorted out which would be expected to present a reference basis for improcing accurcy, effectiveness and reliability of dynamic characteristic identification for super high-rise buildings and provide reference to improving operation and maintenance levels for super high-rise buildings in China.
The acceleration of urbanization has led to a sharp rise in the number of super high-rise buildings in China. However, the issues related to the operation and maintenance of those buildings have become increasingly prominent. As a result, extensive attention to the service safety of super high-rise buildings have been paid. Summarizing and analyzing the theoretical methods and practical applications of identifying dynamic characteristic parameters of super high-rise buildings, the characteristics of super high-rise building structure monitoring technique, which were represented by the time domain, frequency domain, time-frequency domain and the new modal recognition method. Subsequently, the advantages and limitations of each monitoring method and system were compared. Simultaneously, the main issues in the current monitoring technique for super high-rise buildings were summed and development trends of monitoring methods were discussed. Eventually, the application of dynamic characteristic identification in the monitoring of super high-rise buildings was sorted out which would be expected to present a reference basis for improcing accurcy, effectiveness and reliability of dynamic characteristic identification for super high-rise buildings and provide reference to improving operation and maintenance levels for super high-rise buildings in China.
2024, 54(1): 11-19.
doi: 10.3724/j.gyjzG23120501
Abstract:
Fatigue failure is one of the main causes of metal structure damage, and if corrosion is considered, the problem becomes more complex. Domestic and foreign scholars have conducted systematic and comprehensive research on the fatigue properties of corroded steel components. The paper critically reviewed and analyzed the state-of-the-art on fatigue properties of corroded steel elements subjected to marine atmosphere in terms of electrochemical corrosion process, corrosion characterization, fatigue properties of corroded steel components. It was found that the electrochemical process of steel corrosion, the general laws of fatigue properties of corroded steels, the characterization of corroded steel surfaces based on a single index have been clearly understood. However, the accurate evaluation of the evolution of fatigue properties of corroded steel structures still faces significant challenges. It is suggested to further identify the spatiotemporal distribution and random models of morphological characteristics of corroded steels, the similarity of steel corrosion mechanisms between natural and artificial environmental conditions, the random evolution mechanism of fatigue properties of corroded steel structures in marine atmospheric environment, as well as the control and improvement of the fatigue properties of corroded steel structures.
Fatigue failure is one of the main causes of metal structure damage, and if corrosion is considered, the problem becomes more complex. Domestic and foreign scholars have conducted systematic and comprehensive research on the fatigue properties of corroded steel components. The paper critically reviewed and analyzed the state-of-the-art on fatigue properties of corroded steel elements subjected to marine atmosphere in terms of electrochemical corrosion process, corrosion characterization, fatigue properties of corroded steel components. It was found that the electrochemical process of steel corrosion, the general laws of fatigue properties of corroded steels, the characterization of corroded steel surfaces based on a single index have been clearly understood. However, the accurate evaluation of the evolution of fatigue properties of corroded steel structures still faces significant challenges. It is suggested to further identify the spatiotemporal distribution and random models of morphological characteristics of corroded steels, the similarity of steel corrosion mechanisms between natural and artificial environmental conditions, the random evolution mechanism of fatigue properties of corroded steel structures in marine atmospheric environment, as well as the control and improvement of the fatigue properties of corroded steel structures.
2024, 54(1): 20-30.
doi: 10.3724/j.gyjzG23120812
Abstract:
China′s urban development has shifted from incremental planning to inventory planning. With the goal of high quality development, retrofitting and performance improvement for existing building structures have become the main task of building sector at present or even for a quite long time. The paper introduced the developmet process from retrofitting to performance improvement of existing building structures, systematically expounded the latest research results of existing building structure reconstruction at home and abroad from three aspects: safety and seismic performance appraisal, retrofitting and performance improvement technology, and resilience evaluation. Moreover, the technical problems existing in the safety and seismic performance evaluation of existing building structures were pointed out. Finally, the future development of retrofitting and performance improvement for existing building structures was prospected.
China′s urban development has shifted from incremental planning to inventory planning. With the goal of high quality development, retrofitting and performance improvement for existing building structures have become the main task of building sector at present or even for a quite long time. The paper introduced the developmet process from retrofitting to performance improvement of existing building structures, systematically expounded the latest research results of existing building structure reconstruction at home and abroad from three aspects: safety and seismic performance appraisal, retrofitting and performance improvement technology, and resilience evaluation. Moreover, the technical problems existing in the safety and seismic performance evaluation of existing building structures were pointed out. Finally, the future development of retrofitting and performance improvement for existing building structures was prospected.
2024, 54(1): 31-45.
doi: 10.3724/j.gyjzG23073008
Abstract:
Because of the significant characteristics of cementitious grouting materials (‘CGM’) include high fluidity, micro expansion, and high strength, it has been widely used in various engineering projects and showing a trend of continuous differentiation in properties. For the development and application of CGM, the development history has been summarized in stages firstly. For the second, the classification of CGM based on its characteristics of properties, application field, and the correlation between each other has been analyzed and summarized systematically. Typical application cases of CGM with different uses were introduced according to its classification by application field. Finally, by combing through the development situation of CGM standardization in China, the future of development and application of CGM is prospected, and several suggestions of research and engineering application were proposed.
Because of the significant characteristics of cementitious grouting materials (‘CGM’) include high fluidity, micro expansion, and high strength, it has been widely used in various engineering projects and showing a trend of continuous differentiation in properties. For the development and application of CGM, the development history has been summarized in stages firstly. For the second, the classification of CGM based on its characteristics of properties, application field, and the correlation between each other has been analyzed and summarized systematically. Typical application cases of CGM with different uses were introduced according to its classification by application field. Finally, by combing through the development situation of CGM standardization in China, the future of development and application of CGM is prospected, and several suggestions of research and engineering application were proposed.
2024, 54(1): 46-55.
doi: 10.3724/j.gyjzG23100822
Abstract:
Oil and gas energy is abundant in Arctic region, which has a great exploitation potential. Concrete gravity-based structures have a board future to be installed in the ocean due to its advantages of high degree of integration and exceptional durability. The calculation methods for ice load, wind load, wave load, ocean current load, foundation reaction, and temperature load were provided in the study based on an oil and gas exploration project in the Arctic region. For the load combinations of gravity-based platforms, standards in China Classification Society (CCS), International Organization for Standardization (ISO), Det Norske Veritas (DNV), American Petroleum Institute (API) and European Union (EN) were introduced to select load types. Then the load combination of the project was defined. Besides, the whole-process structural analysis for towage, installation, and on-site service was carried out by finite element method, verifying the reliability of the platform.
Oil and gas energy is abundant in Arctic region, which has a great exploitation potential. Concrete gravity-based structures have a board future to be installed in the ocean due to its advantages of high degree of integration and exceptional durability. The calculation methods for ice load, wind load, wave load, ocean current load, foundation reaction, and temperature load were provided in the study based on an oil and gas exploration project in the Arctic region. For the load combinations of gravity-based platforms, standards in China Classification Society (CCS), International Organization for Standardization (ISO), Det Norske Veritas (DNV), American Petroleum Institute (API) and European Union (EN) were introduced to select load types. Then the load combination of the project was defined. Besides, the whole-process structural analysis for towage, installation, and on-site service was carried out by finite element method, verifying the reliability of the platform.
2024, 54(1): 56-60.
doi: 10.3724/j.gyjzG21091409
Abstract:
3D printing construction technology is a new type of digital construction technology that applies 3D printing technology to the construction field. It is an intelligent building manufacturing mode characterized by the deep integration of information integration technology and digital manufacturing technology. This building construction method has a series of advantages such as intelligence, personalization, and low emissions, and is an ideal building model for future buildings. At present, the development and application of 3D printing building technology is still in the primary stage, and there is little research on the mechanical properties of various 3D printing building components. Basing on the previous 3D printed concrete beam tests of the research group, the paper established a finite element model, carried out further parameter analysis, and focused on the influence of the characteristics of printing path and bonding surface (between the 3D printed concrete outer frame and the core area concrete) on the bearing capacity of 3D printed concrete beams. The research showed that the 3D printed concrete beam numerical model established in the paper showed a high reliability, and the load-displacement curves were basically consistent with the test results; the beams with rotary printing path showed a higher bearing capacity; and the bonding characteristics between the core area and the 3D printed outer frame had a significant impact on the bearing capacity of the beams. Improving the bonding strength of the bonding surface could effectively improve the ultimate bearing capacity of 3D printed concrete beams.
3D printing construction technology is a new type of digital construction technology that applies 3D printing technology to the construction field. It is an intelligent building manufacturing mode characterized by the deep integration of information integration technology and digital manufacturing technology. This building construction method has a series of advantages such as intelligence, personalization, and low emissions, and is an ideal building model for future buildings. At present, the development and application of 3D printing building technology is still in the primary stage, and there is little research on the mechanical properties of various 3D printing building components. Basing on the previous 3D printed concrete beam tests of the research group, the paper established a finite element model, carried out further parameter analysis, and focused on the influence of the characteristics of printing path and bonding surface (between the 3D printed concrete outer frame and the core area concrete) on the bearing capacity of 3D printed concrete beams. The research showed that the 3D printed concrete beam numerical model established in the paper showed a high reliability, and the load-displacement curves were basically consistent with the test results; the beams with rotary printing path showed a higher bearing capacity; and the bonding characteristics between the core area and the 3D printed outer frame had a significant impact on the bearing capacity of the beams. Improving the bonding strength of the bonding surface could effectively improve the ultimate bearing capacity of 3D printed concrete beams.
2024, 54(1): 61-67.
doi: 10.3724/j.gyjzG23022008
Abstract:
Micro vibration control is one of the most important goals in the construction of ultraprecise and large-scale scientific facilities. In order to meet the requirements for micro vibration control in High Energy Photo Source (HEPS), Beijing, a 1-meter-thick reinforced concrete slab with a 3-meter-thick concrete layer has been cast. The paper presented a field test of an artificial frequency sweep test from 1 to 100 Hz after the completion of the main structure in HEPS. Based on the analysis of the obtained vibration signals in the time domain and frequency domain, an evaluation of the micro vibration level and the micro vibration control capacity of the slab was conducted. The results indicated that under the vibrator’s excitation from 1 to 100 Hz, the mass concrete slab of experimental hall performed well in micro vibration control.
Micro vibration control is one of the most important goals in the construction of ultraprecise and large-scale scientific facilities. In order to meet the requirements for micro vibration control in High Energy Photo Source (HEPS), Beijing, a 1-meter-thick reinforced concrete slab with a 3-meter-thick concrete layer has been cast. The paper presented a field test of an artificial frequency sweep test from 1 to 100 Hz after the completion of the main structure in HEPS. Based on the analysis of the obtained vibration signals in the time domain and frequency domain, an evaluation of the micro vibration level and the micro vibration control capacity of the slab was conducted. The results indicated that under the vibrator’s excitation from 1 to 100 Hz, the mass concrete slab of experimental hall performed well in micro vibration control.
2024, 54(1): 68-75.
doi: 10.3724/j.gyjzG23020714
Abstract:
In order to realize the assembly of long-span steel structures such as single-layer reticulated shell, the T-shaped steel joint with cover plates (TSJC) was put forward, which can be used to connect circular steel tubes of single-layer reticulated shell. The TSJC joint consists of T-shaped plates, cover plates, ear plates, high-strength bolts, sealing plates and circular steel tubes. By adjusting the design parameters of components, the bending stiffness and bearing capacity of TSJC joint could be controlled. Finite element models of TSJC joints were established and the flexural performance of TSJC joints in in-plane and out-plane direction were analyzed. The influence of the thickness of T-shaped plate flange, T-shaped plate web, cover plates and ear plates on the bending stiffness, bearing capacity and failure modes of TSJC joints were studied. The results showed that the TSJC joints exhibited good bending stiffness and bearing capacity. By changing the thickness of T-shaped flange plates, T-shaped web plates, cover plates or ear plates, the differences of the bending stiffness and bearing capacity of TSJC joints in in-plane and out-plane directions could be controlled.
In order to realize the assembly of long-span steel structures such as single-layer reticulated shell, the T-shaped steel joint with cover plates (TSJC) was put forward, which can be used to connect circular steel tubes of single-layer reticulated shell. The TSJC joint consists of T-shaped plates, cover plates, ear plates, high-strength bolts, sealing plates and circular steel tubes. By adjusting the design parameters of components, the bending stiffness and bearing capacity of TSJC joint could be controlled. Finite element models of TSJC joints were established and the flexural performance of TSJC joints in in-plane and out-plane direction were analyzed. The influence of the thickness of T-shaped plate flange, T-shaped plate web, cover plates and ear plates on the bending stiffness, bearing capacity and failure modes of TSJC joints were studied. The results showed that the TSJC joints exhibited good bending stiffness and bearing capacity. By changing the thickness of T-shaped flange plates, T-shaped web plates, cover plates or ear plates, the differences of the bending stiffness and bearing capacity of TSJC joints in in-plane and out-plane directions could be controlled.
2024, 54(1): 76-85.
doi: 10.3724/j.gyjzG23072810
Abstract:
The traditional stability design method for scaffolding structures is based on linear calculation results and the theory of effective length coefficients. The traditional method is accurate enough for conventional scaffolding structures, provided that the effective length coefficient of the compressed member can be correctly evaluated. However, a fine design method with higher calculation accuracy should be adopted for the design of ultra-high and large scaffold structures with complex loading conditions. An advanced design method for scaffolding based on direct analysis method was proposed in the paper. Firstly, a large number of geometric measurements and statistical analysis about the initial bending of scaffolding members were carried out, and an accurate data model for initial defect of scaffolding members was established. Secondly, an experimental research was conducted on the typical connection joints of the buckle type scaffold, and the semi-rigid characteristic of the connection with different loading cases were obtained, including bending in beams, compression or tension in beams and braces. Moreover, the research results including initial defect of scaffolding members and semi-rigid properties of scaffolding connection were imported into the nonlinear structure analysis tools NIDA. Finally, a real project with ultra-high and large disk-buckled scaffolding structure was introduced.
The traditional stability design method for scaffolding structures is based on linear calculation results and the theory of effective length coefficients. The traditional method is accurate enough for conventional scaffolding structures, provided that the effective length coefficient of the compressed member can be correctly evaluated. However, a fine design method with higher calculation accuracy should be adopted for the design of ultra-high and large scaffold structures with complex loading conditions. An advanced design method for scaffolding based on direct analysis method was proposed in the paper. Firstly, a large number of geometric measurements and statistical analysis about the initial bending of scaffolding members were carried out, and an accurate data model for initial defect of scaffolding members was established. Secondly, an experimental research was conducted on the typical connection joints of the buckle type scaffold, and the semi-rigid characteristic of the connection with different loading cases were obtained, including bending in beams, compression or tension in beams and braces. Moreover, the research results including initial defect of scaffolding members and semi-rigid properties of scaffolding connection were imported into the nonlinear structure analysis tools NIDA. Finally, a real project with ultra-high and large disk-buckled scaffolding structure was introduced.
2024, 54(1): 86-95.
doi: 10.3724/j.gyjzG23092513
Abstract:
A large-diameter inclined steel-reinforced concrete (SRC) column system is utilized in the underground structure of the Shenzhen Huangmugang comprehensive transportation hub, enhancing both the architectural aesthetics and the transferring comfort while meeting operational requirements. The SRC columns are vertically inclined and have a maximum inclination angle of 13°, and the columns connected to the horizontal beams in the structure, are located outside the beam-beam joints. To investigate the mechanical Properties of the inclined columns, a specimen on a scale of 1/8 was designed and fabricated, and the failure process and response of the column were determined by static test in combination with axial load, shear force, and bending moment. ABAQUS software was employed to further determine the mechanical properties of the inclined SRC column. The results revealed that the horizontal beams and corbels could effectively restrain the lateral deformation of the inclined columns in both directions. The bearing capacity of the inclined columns was 1.62 times the design load, indicating the design was safe and reliable. When the load reached its peak, the in-plane and out-plane lateral displacement was 1/3 046 and 1/3 236 of the length of the inclined column. The concrete in the middle and bottom zone of the upper column region was crushed significantly and the longitudinal steel bar also buckled, and few cracks were observed at the side surface of the corbels.
A large-diameter inclined steel-reinforced concrete (SRC) column system is utilized in the underground structure of the Shenzhen Huangmugang comprehensive transportation hub, enhancing both the architectural aesthetics and the transferring comfort while meeting operational requirements. The SRC columns are vertically inclined and have a maximum inclination angle of 13°, and the columns connected to the horizontal beams in the structure, are located outside the beam-beam joints. To investigate the mechanical Properties of the inclined columns, a specimen on a scale of 1/8 was designed and fabricated, and the failure process and response of the column were determined by static test in combination with axial load, shear force, and bending moment. ABAQUS software was employed to further determine the mechanical properties of the inclined SRC column. The results revealed that the horizontal beams and corbels could effectively restrain the lateral deformation of the inclined columns in both directions. The bearing capacity of the inclined columns was 1.62 times the design load, indicating the design was safe and reliable. When the load reached its peak, the in-plane and out-plane lateral displacement was 1/3 046 and 1/3 236 of the length of the inclined column. The concrete in the middle and bottom zone of the upper column region was crushed significantly and the longitudinal steel bar also buckled, and few cracks were observed at the side surface of the corbels.
2024, 54(1): 96-101.
doi: 10.3724/j.gyjzG23082210
Abstract:
With the development of urban rail transit and the deepening of integration of under-and above-ground urban space, the rail transit co-construction project has become a new direction of the public transportation-oriented development mode. Relying on the Dongguan Xiping Station project, a combined structural scheme was designed for the long-span building cover and conversion beam area, which could reduce the height of beams by 28%-33%, the dead weight by 49%-66%, and the cost by 7%-36%. The overall model of the steel reinforced concrete structure and the steel-concrete composite structure were established and the seismic performance analysis of the two structures under different earthquake was carried out by YJK and MIDAS Gen. The composite structure decreased the interlayer displacement angle under rarely occurred earthquake, which suggested that it showed a better seismic resistance while maintaining natural vibration characteristics similar to the steel reinforced concrete structure. It was notable that the bending-torsional coupling effect in the transformation beam area is significant, resulting in the torque reached up to 2 719.4 kN·m; and the stress of the long-span steel structure reached up to 207 MPa.
With the development of urban rail transit and the deepening of integration of under-and above-ground urban space, the rail transit co-construction project has become a new direction of the public transportation-oriented development mode. Relying on the Dongguan Xiping Station project, a combined structural scheme was designed for the long-span building cover and conversion beam area, which could reduce the height of beams by 28%-33%, the dead weight by 49%-66%, and the cost by 7%-36%. The overall model of the steel reinforced concrete structure and the steel-concrete composite structure were established and the seismic performance analysis of the two structures under different earthquake was carried out by YJK and MIDAS Gen. The composite structure decreased the interlayer displacement angle under rarely occurred earthquake, which suggested that it showed a better seismic resistance while maintaining natural vibration characteristics similar to the steel reinforced concrete structure. It was notable that the bending-torsional coupling effect in the transformation beam area is significant, resulting in the torque reached up to 2 719.4 kN·m; and the stress of the long-span steel structure reached up to 207 MPa.
2024, 54(1): 102-114.
doi: 10.3724/j.gyjzG23092901
Abstract:
As the most similar exoplanet in the solar system, Mars is very important in the perspective of strategic value and significance. With the completion of the three missions of “orbiting, landing and patrolling” of Mars at one time, the Martian base construction has become the next important goal to promote our deep space exploration process. Through the investigation of the existing literature on the environment and resource conditions of Mars, comparing them with those on the moon and the Earth, a series of unique problems to be solved in the construction of Mars are put forward. Based on the investigation of technologies suitable for Mars construction, including excavation construction, chemical vapor deposition forming, fused deposition forming, and Martian regolith bonding forming, etc., a new scheme of automatic construction of Martian base based on in-situ resources is proposed, called “China Dome”, which components include an inflatable bag, carbon fiber skeleton, sulfur concrete cladding and hatches. This provides a new way to build a Martian base.
As the most similar exoplanet in the solar system, Mars is very important in the perspective of strategic value and significance. With the completion of the three missions of “orbiting, landing and patrolling” of Mars at one time, the Martian base construction has become the next important goal to promote our deep space exploration process. Through the investigation of the existing literature on the environment and resource conditions of Mars, comparing them with those on the moon and the Earth, a series of unique problems to be solved in the construction of Mars are put forward. Based on the investigation of technologies suitable for Mars construction, including excavation construction, chemical vapor deposition forming, fused deposition forming, and Martian regolith bonding forming, etc., a new scheme of automatic construction of Martian base based on in-situ resources is proposed, called “China Dome”, which components include an inflatable bag, carbon fiber skeleton, sulfur concrete cladding and hatches. This provides a new way to build a Martian base.
2024, 54(1): 115-122.
doi: 10.3724/j.gyjzG23111502
Abstract:
Considering the problem of uneven cross-section of material of large-diameter steel rebars and the stress concentration at the root of thread rebars, the paper carried out an experimental study of uniaxial tensile and fatigue properties of materials at different positions of the cross-section of 930 MPa grade 75 mm diameter high-strength cold-rolled threaded prestressed steel rebars, and carried out a finite element numerical simulation of full-size steel rebars under uniaxial tensile to analyze the stress concentration at the thread root. The results showed that there was no yield platform in the stress-strain curves of large-diameter high-strength cold-rolled threaded prestressed steel rebars under uniaxial tensile, and there were significant differences in the cross-sectional material properties of the 930 MPa grade 75 mm diameter steel rebars. There was an obvious stress concentration at the thread root, and the stress concentration coefficient was about 1.74, and the fatigue properties was very close to the Z11 curve considering the size effect in the Steel Structure Design Standard (GB 50017—2017) when the average stress was 700 MPa.
Considering the problem of uneven cross-section of material of large-diameter steel rebars and the stress concentration at the root of thread rebars, the paper carried out an experimental study of uniaxial tensile and fatigue properties of materials at different positions of the cross-section of 930 MPa grade 75 mm diameter high-strength cold-rolled threaded prestressed steel rebars, and carried out a finite element numerical simulation of full-size steel rebars under uniaxial tensile to analyze the stress concentration at the thread root. The results showed that there was no yield platform in the stress-strain curves of large-diameter high-strength cold-rolled threaded prestressed steel rebars under uniaxial tensile, and there were significant differences in the cross-sectional material properties of the 930 MPa grade 75 mm diameter steel rebars. There was an obvious stress concentration at the thread root, and the stress concentration coefficient was about 1.74, and the fatigue properties was very close to the Z11 curve considering the size effect in the Steel Structure Design Standard (GB 50017—2017) when the average stress was 700 MPa.
2024, 54(1): 123-129.
doi: 10.3724/j.gyjzG23072612
Abstract:
In the field of structural damage identification, the Cross Model Cross Mode (CMCM) Method is constrained by the rank deficiency of the coefficient matrix when solving noise-inclusive damage identification problems, leading to a decrease in the accuracy of damage identification results. To address this issue, this study proposes a two-stage damage identification method aimed at reducing the redundant equations in the CMCM method’s coefficient matrix, thereby enhancing the computational performance and noise robustness of the CMCM method. In the first stage, a Convolutional Neural Network (CNN) is employed for structural damage localization to eliminate the redundant equations in the coefficient matrix of the CMCM method. Subsequently, in the second stage, the reduced CMCM coefficient matrix equation is solved to obtain more accurate damage identification results. The effectiveness of the proposed two-stage damage identification method is validated through numerical and experimental studies. Compared with the traditional CMCM method, the method proposed in this paper significantly improves the accuracy of damage identification in solving noise-inclusive damage identification problems, demonstrating its superior performance.
In the field of structural damage identification, the Cross Model Cross Mode (CMCM) Method is constrained by the rank deficiency of the coefficient matrix when solving noise-inclusive damage identification problems, leading to a decrease in the accuracy of damage identification results. To address this issue, this study proposes a two-stage damage identification method aimed at reducing the redundant equations in the CMCM method’s coefficient matrix, thereby enhancing the computational performance and noise robustness of the CMCM method. In the first stage, a Convolutional Neural Network (CNN) is employed for structural damage localization to eliminate the redundant equations in the coefficient matrix of the CMCM method. Subsequently, in the second stage, the reduced CMCM coefficient matrix equation is solved to obtain more accurate damage identification results. The effectiveness of the proposed two-stage damage identification method is validated through numerical and experimental studies. Compared with the traditional CMCM method, the method proposed in this paper significantly improves the accuracy of damage identification in solving noise-inclusive damage identification problems, demonstrating its superior performance.
Static and Dynamic Deformation Monitoring of Super High-Rise Buildings During the Construction Stage
2024, 54(1): 130-139.
doi: 10.3724/j.gyjzG23081112
Abstract:
To address the insufficient research on the measurement of static and dynamic deformations of super high- rise buildings during the construction stage, a structural health monitoring (SHM) system was installed on the main structure of a practical super high-rise building with a height of 335 m.Thus the temperature deformation, vertical deformation, and dynamic displacement of the main structure during the construction stage were measured and analyzed. The uneven distribution of temperature in the main structure during the construction stage was identified, and the strain characteristics of the structure under the influence of temperature were analyzed. The results showed that the strain caused by seasonal temperature difference was greater than the strain caused by the self-weight of the upper structure and the concrete shrinkage and creep over the same period. The developments of the vertical deformation and the inter-story uneven deformation during the construction stage were explained. The degree of uneven deformation increased with structural height and time. The maximum deformation difference among the points of the same floor was 5.3 mm. The axial stress of the girder was positive correlated with the difference in vertical strain between the two ends of the girder. The difference in vertical deformation between the outer frame and the core tube could lead to tensile cracking in the girder. A structural dynamic displacement estimation method based on Kalman filtering was proposed, which could improve could the accuracy of dynamic displacement estimation by fusing acceleration data and strain data, and could accurately estimate the dynamic displacement of super high-rise building under dynamic construction loads.
To address the insufficient research on the measurement of static and dynamic deformations of super high- rise buildings during the construction stage, a structural health monitoring (SHM) system was installed on the main structure of a practical super high-rise building with a height of 335 m.Thus the temperature deformation, vertical deformation, and dynamic displacement of the main structure during the construction stage were measured and analyzed. The uneven distribution of temperature in the main structure during the construction stage was identified, and the strain characteristics of the structure under the influence of temperature were analyzed. The results showed that the strain caused by seasonal temperature difference was greater than the strain caused by the self-weight of the upper structure and the concrete shrinkage and creep over the same period. The developments of the vertical deformation and the inter-story uneven deformation during the construction stage were explained. The degree of uneven deformation increased with structural height and time. The maximum deformation difference among the points of the same floor was 5.3 mm. The axial stress of the girder was positive correlated with the difference in vertical strain between the two ends of the girder. The difference in vertical deformation between the outer frame and the core tube could lead to tensile cracking in the girder. A structural dynamic displacement estimation method based on Kalman filtering was proposed, which could improve could the accuracy of dynamic displacement estimation by fusing acceleration data and strain data, and could accurately estimate the dynamic displacement of super high-rise building under dynamic construction loads.
2024, 54(1): 140-146.
doi: 10.3724/j.gyjzG23092009
Abstract:
The roof of large storage tank is prone to instability under external pressure due to its thin wall and large span. Taking a large 20 000-ton composite storage tank as an example, in order to improve the stability of the tank roof, four reinforcement schemes were proposed, such as composite arch reinforcement, composite arch-I-beam-channel steel combined reinforcement, I-beam-channel steel combined reinforcement, and triangular steel truss reinforcement. A finite element model was established to perform buckling analysis of the tank roof before and after reinforcement. It was shown that the stability coefficient of the tank roof before reinforcement was 1.29, which was much smaller than the requirements of a stability coefficient of 15 in Steel pressure vessels (GB 150—1998). Except for the composite arch reinforcement, other reinforcement schemes that combined steel structures with composite materials exhibited favorable effects, and the stability coefficient of the tank roof after reinforcement could meet the requirements of GB 150—1998. Based on this, the cost and construction processes of each reinforcement scheme were systematically analyzed. The small cross-sectional triangular steel truss reinforcement scheme was identified as the optimal solution for the composite tank roof, which could provid technical reference for the reinforcement and optimization design of large composite storage tank roofs.
The roof of large storage tank is prone to instability under external pressure due to its thin wall and large span. Taking a large 20 000-ton composite storage tank as an example, in order to improve the stability of the tank roof, four reinforcement schemes were proposed, such as composite arch reinforcement, composite arch-I-beam-channel steel combined reinforcement, I-beam-channel steel combined reinforcement, and triangular steel truss reinforcement. A finite element model was established to perform buckling analysis of the tank roof before and after reinforcement. It was shown that the stability coefficient of the tank roof before reinforcement was 1.29, which was much smaller than the requirements of a stability coefficient of 15 in Steel pressure vessels (GB 150—1998). Except for the composite arch reinforcement, other reinforcement schemes that combined steel structures with composite materials exhibited favorable effects, and the stability coefficient of the tank roof after reinforcement could meet the requirements of GB 150—1998. Based on this, the cost and construction processes of each reinforcement scheme were systematically analyzed. The small cross-sectional triangular steel truss reinforcement scheme was identified as the optimal solution for the composite tank roof, which could provid technical reference for the reinforcement and optimization design of large composite storage tank roofs.
2024, 54(1): 147-155.
doi: 10.3724/j.gyjzG23112905
Abstract:
Based on the characteristics of the construction process of prefabricated steel structures, a process-based construction carbon emission calculation method was proposed, and the feasibility of the method was verified in a case study of a multi-story steel-structured data center project. Through on-site measurement and investigation, the basic parameters of construction process-specific carbon emissions in 10 processes of floor deck, shear nails, steel rebars and concrete works were obtained. The calculation results were uniformly characterized as carbon emissions per square meter of floor area, and it showed that the total carbon emissions of steel structure floor construction were 0.759 5 kgCO2/m2 floor area, which was equivalent to 1.64% of the building material embodied carbon emissions of the floor construction. The carbon emission contribution was concrete works (0.477 8 kgCO2/m2 floor area), steel rebar works (0.181 5 kgCO2/m2 floor area), shear nail works (0.067 1 kgCO2/m2 floor area), and floor deck works (0.033 1 kgCO2/m2 floor area) in descending order. Among them, the carbon emissions by construction energy and material consumption accounted for 72.6% and 27.4%, respectively, and the generated direct, indirect, and embodied carbon emissions accounted for 62.9%, 9.7% and 27.4%, respectively. Based on the calculation method proposed by this study, the results obtained could show the main carbon emission sources, which was conducive to tracing the carbon emission hotspots of steel structure construction and formulating corresponding carbon reduction measures. In this case, the construction processes that generated carbon emissions more than 5% of total were the concrete mixing process, steel rebar lashing process, concrete pumping process, and shear nail welding process, which together generated 88.9% of the total carbon emissions of floor construction.
Based on the characteristics of the construction process of prefabricated steel structures, a process-based construction carbon emission calculation method was proposed, and the feasibility of the method was verified in a case study of a multi-story steel-structured data center project. Through on-site measurement and investigation, the basic parameters of construction process-specific carbon emissions in 10 processes of floor deck, shear nails, steel rebars and concrete works were obtained. The calculation results were uniformly characterized as carbon emissions per square meter of floor area, and it showed that the total carbon emissions of steel structure floor construction were 0.759 5 kgCO2/m2 floor area, which was equivalent to 1.64% of the building material embodied carbon emissions of the floor construction. The carbon emission contribution was concrete works (0.477 8 kgCO2/m2 floor area), steel rebar works (0.181 5 kgCO2/m2 floor area), shear nail works (0.067 1 kgCO2/m2 floor area), and floor deck works (0.033 1 kgCO2/m2 floor area) in descending order. Among them, the carbon emissions by construction energy and material consumption accounted for 72.6% and 27.4%, respectively, and the generated direct, indirect, and embodied carbon emissions accounted for 62.9%, 9.7% and 27.4%, respectively. Based on the calculation method proposed by this study, the results obtained could show the main carbon emission sources, which was conducive to tracing the carbon emission hotspots of steel structure construction and formulating corresponding carbon reduction measures. In this case, the construction processes that generated carbon emissions more than 5% of total were the concrete mixing process, steel rebar lashing process, concrete pumping process, and shear nail welding process, which together generated 88.9% of the total carbon emissions of floor construction.
2024, 54(1): 156-164.
doi: 10.3724/j.gyjzG23072112
Abstract:
Yingxian Wood Pagoda is the oldest and highest pavilion-like wood pagoda in the world, which represents the highest level of wood construction technology in China. As, the wood pagoda has suffered plenty of weathering, disasters and wars, it is urgent to be protected and repaired from its increasing damage and deformation with time. The value analysis is the optimized task of a heritage protection. Therefore, the value composition of Yingxian Wood Pagoda was analyzed from history, science, art and social culture and other multi-value perspectives. The historic value of the wood pagoda was explored from the aspects of architectural styles, structure damages, member forms, Buddhas and hoards. The scientific value of wood tower was explored from the aspect of the structure system and proportion scale. The artistic value was explored from architectural form proportions, Dougong, Buddhas, murals, plaques, wind chimes and calligraphy. The social and cultural values were explored from social condensation, cultural diversity and landscape resources, which was expected to provide reference to future conservation of historical heritage.
Yingxian Wood Pagoda is the oldest and highest pavilion-like wood pagoda in the world, which represents the highest level of wood construction technology in China. As, the wood pagoda has suffered plenty of weathering, disasters and wars, it is urgent to be protected and repaired from its increasing damage and deformation with time. The value analysis is the optimized task of a heritage protection. Therefore, the value composition of Yingxian Wood Pagoda was analyzed from history, science, art and social culture and other multi-value perspectives. The historic value of the wood pagoda was explored from the aspects of architectural styles, structure damages, member forms, Buddhas and hoards. The scientific value of wood tower was explored from the aspect of the structure system and proportion scale. The artistic value was explored from architectural form proportions, Dougong, Buddhas, murals, plaques, wind chimes and calligraphy. The social and cultural values were explored from social condensation, cultural diversity and landscape resources, which was expected to provide reference to future conservation of historical heritage.
