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2013 Vol. 43, No. 5
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2013, 43(5): 5-8.
doi: 10.13204/j.gyjz201305001
Abstract:
Suspened-dome structure is a new kind of hybrid space structure with the combination of an upper single-layer lattice shell and a lower cable-strut system, and has a very broad applied prospect.The research state of construction analysis is first introduced.The key problems in construction analysis are then pointed out, including determination of the geometric model and control of the prestressing force.Followed that, experiment of the scaled model is carried out and two construction schemes are proposed according to the pretension element, number of simultaneously pretension point and prestressing force level.The theoretical results are compared with that obtained form the experiment.The research here will provide a reference for construction of similar suspened-dome structures.
Suspened-dome structure is a new kind of hybrid space structure with the combination of an upper single-layer lattice shell and a lower cable-strut system, and has a very broad applied prospect.The research state of construction analysis is first introduced.The key problems in construction analysis are then pointed out, including determination of the geometric model and control of the prestressing force.Followed that, experiment of the scaled model is carried out and two construction schemes are proposed according to the pretension element, number of simultaneously pretension point and prestressing force level.The theoretical results are compared with that obtained form the experiment.The research here will provide a reference for construction of similar suspened-dome structures.
2013, 43(5): 9-13.
doi: 10.13204/j.gyjz201305002
Abstract:
Considering the influences of high strength concrete's shrinkage and creep deformation on the vertical deformation and the structural stress, using the finite element software, combined with Wuhan Centre Project, mechanical simulation and stress state analysis for giant column frame-core tube-canlilever truss structure system construction process were given.The calculation results show that in the gravity and construction load, the deformation exists between the elevation position of floor and the design position, maximum deformation difference occurred in middle of tower, the advance construction of the core tube has certain influence on the vertical deformation, but a small influence on the whole deformation, which can be adjusted by making level in the construction process.
Considering the influences of high strength concrete's shrinkage and creep deformation on the vertical deformation and the structural stress, using the finite element software, combined with Wuhan Centre Project, mechanical simulation and stress state analysis for giant column frame-core tube-canlilever truss structure system construction process were given.The calculation results show that in the gravity and construction load, the deformation exists between the elevation position of floor and the design position, maximum deformation difference occurred in middle of tower, the advance construction of the core tube has certain influence on the vertical deformation, but a small influence on the whole deformation, which can be adjusted by making level in the construction process.
2013, 43(5): 14-17,51.
doi: 10.13204/j.gyjz201305003
Abstract:
In the construction of super-high buildings, jacking form is a new technology.As the long time of final setting of high strength concrete, it is disadvantageous to do construction with periodic template model for a project.Taking actual projects for example, the system of jacking form was designed and numerical simulation and model analysis were done by SAP 2000, hence the optimization of the whole jacking forms was done and the best design proposal was got.
In the construction of super-high buildings, jacking form is a new technology.As the long time of final setting of high strength concrete, it is disadvantageous to do construction with periodic template model for a project.Taking actual projects for example, the system of jacking form was designed and numerical simulation and model analysis were done by SAP 2000, hence the optimization of the whole jacking forms was done and the best design proposal was got.
2013, 43(5): 18-23,93.
doi: 10.13204/j.gyjz201305004
Abstract:
Ecological composite wall structure system is a new building structure seismic system with the function of lightweight, high strength, which can improve the performance of buildings greatly, and its economic benefits is significant, it accords with national sustainable development strategies and plays a great promoting role in the progress of science and technology of the industry.Combined with the engineering construction of Zhongzhou Royal Palace ecological composite wall structure system of Kaifeng County in Henan Province.It was mainly introduced the production technology of ecological composite walls, the installation and connection procedures of ecological composite walls, external wall insulation board processing measures, analysis of the effect of energy conservation and environmental protection;also, it was made a detailed analysis and summary of the cooperation between the construction of the main structure and other types of constructions, thus perfecting the construction method of the ecological composite wall structure system, by which excellent quality of the project was achieved.
Ecological composite wall structure system is a new building structure seismic system with the function of lightweight, high strength, which can improve the performance of buildings greatly, and its economic benefits is significant, it accords with national sustainable development strategies and plays a great promoting role in the progress of science and technology of the industry.Combined with the engineering construction of Zhongzhou Royal Palace ecological composite wall structure system of Kaifeng County in Henan Province.It was mainly introduced the production technology of ecological composite walls, the installation and connection procedures of ecological composite walls, external wall insulation board processing measures, analysis of the effect of energy conservation and environmental protection;also, it was made a detailed analysis and summary of the cooperation between the construction of the main structure and other types of constructions, thus perfecting the construction method of the ecological composite wall structure system, by which excellent quality of the project was achieved.
2013, 43(5): 24-27,78.
doi: 10.13204/j.gyjz201305005
Abstract:
The containment which provides protection, sealing and other functions is an important component of third-generation nuclear power plants(European Pressurised Reactor, EPR).Based on a nuclear power plant project, by finite software ANSYS it was analyzed the effects of the following factors on structural mechanical behavior under construction, such as accumulation accuracy of liner installation, modular construction height, pouring concrete lateral pressure and wind loads etc.The maximum radial displacement of the liner and the maximum stress of containment were got;and the pouring concrete lateral pressure of the concrete had the greatest impact on the structure during the construction.In addition, the second-order effects must be taken into account in the simulation.For the nuclear shell cylinder structure, the key technologies and steps of the mesh division were also given, which provided a reference for future analysis of containment.
The containment which provides protection, sealing and other functions is an important component of third-generation nuclear power plants(European Pressurised Reactor, EPR).Based on a nuclear power plant project, by finite software ANSYS it was analyzed the effects of the following factors on structural mechanical behavior under construction, such as accumulation accuracy of liner installation, modular construction height, pouring concrete lateral pressure and wind loads etc.The maximum radial displacement of the liner and the maximum stress of containment were got;and the pouring concrete lateral pressure of the concrete had the greatest impact on the structure during the construction.In addition, the second-order effects must be taken into account in the simulation.For the nuclear shell cylinder structure, the key technologies and steps of the mesh division were also given, which provided a reference for future analysis of containment.
2013, 43(5): 28-32.
doi: 10.13204/j.gyjz201305006
Abstract:
Steel cylinder of the containment was one of the most important structure modules of AP1000 Nuclear Plant.Its characteristics such as large size, heavy weight, thin wall together with the accuracy requirements of installation resulted in the difficulty of lifting.A new lifting method for this large-scale, thin-wall components was put forward: lifting without beam.When using this method, there were three main factors affecting the lifting: the number of slings, the position of lug and the height of the distributor.The finite-element-analysis software ANSYS was used to simulate the lifting.The influence regularity of these three main factors were obtained.It was shown that the deformation and the equivalent stress of the cylinder would be smaller when using more slings, keeping the lugs closer to cylinder's horizontal axis, and the distributor was higher.Compared with the present lifting method, the new method can enhance the crane's actual lifting capacity effectively and reduce the overall load on foundation by removing the heavy octagonal beam.In addition, the new method reduces the deformation at cylinder's edge, therefore reduces the difficulty of abutment between adjacent modules significantly.
Steel cylinder of the containment was one of the most important structure modules of AP1000 Nuclear Plant.Its characteristics such as large size, heavy weight, thin wall together with the accuracy requirements of installation resulted in the difficulty of lifting.A new lifting method for this large-scale, thin-wall components was put forward: lifting without beam.When using this method, there were three main factors affecting the lifting: the number of slings, the position of lug and the height of the distributor.The finite-element-analysis software ANSYS was used to simulate the lifting.The influence regularity of these three main factors were obtained.It was shown that the deformation and the equivalent stress of the cylinder would be smaller when using more slings, keeping the lugs closer to cylinder's horizontal axis, and the distributor was higher.Compared with the present lifting method, the new method can enhance the crane's actual lifting capacity effectively and reduce the overall load on foundation by removing the heavy octagonal beam.In addition, the new method reduces the deformation at cylinder's edge, therefore reduces the difficulty of abutment between adjacent modules significantly.
2013, 43(5): 33-36,85.
doi: 10.13204/j.gyjz201305007
Abstract:
Through the analysis of assembly welding technology of composite box steel columns, the key study was carried out on measures of controlling welding distortions in advance.In addition, the welding sequence of two-line-six-opening composite box steel columns was summarized and technical problems such as controlling welding distortions of composite box steel columns were solved by interpolation method.
Through the analysis of assembly welding technology of composite box steel columns, the key study was carried out on measures of controlling welding distortions in advance.In addition, the welding sequence of two-line-six-opening composite box steel columns was summarized and technical problems such as controlling welding distortions of composite box steel columns were solved by interpolation method.
2013, 43(5): 37-39.
doi: 10.13204/j.gyjz201305008
Abstract:
At present the atrium space is designed for many public buildings.In order to research how to design the atrium space in an ecological building, the paper analyzes five basic atrium forms that have different effects on the internal environment.Depending on the analysis, the atrium space design methods are put forward for the cold climate, hot climate and hot summer and cold winter climate.
At present the atrium space is designed for many public buildings.In order to research how to design the atrium space in an ecological building, the paper analyzes five basic atrium forms that have different effects on the internal environment.Depending on the analysis, the atrium space design methods are put forward for the cold climate, hot climate and hot summer and cold winter climate.
2013, 43(5): 40-43,114.
doi: 10.13204/j.gyjz201305009
Abstract:
Nowdays, renewable energy sources have become important competed development fields, to which much attention has been paid and widely applied in countries all over the world.Taking an energy saving renovation project of Huazhong University of Science and Technology in Wuhan, Hubei Province, as a case, and some energy-saving technical measures were put forward, such as Active Dynamic Air Envelope, climatic adaptive window, underground cool and hot source, solar building integrated system and under floor air supply sytem, etc.Moreover, according to the building's operation and use conditions, the testing analysis was given.For realizing energy saving, land saving, water saving, material saving, environmental protection and reducing pollution, this building made the best of renewable energy sources in order to realize low energy consumption, and the technical reference was provided for promoting application of renewable energy and building energy efficiency in hot-summer and cold-winter zone of China.
Nowdays, renewable energy sources have become important competed development fields, to which much attention has been paid and widely applied in countries all over the world.Taking an energy saving renovation project of Huazhong University of Science and Technology in Wuhan, Hubei Province, as a case, and some energy-saving technical measures were put forward, such as Active Dynamic Air Envelope, climatic adaptive window, underground cool and hot source, solar building integrated system and under floor air supply sytem, etc.Moreover, according to the building's operation and use conditions, the testing analysis was given.For realizing energy saving, land saving, water saving, material saving, environmental protection and reducing pollution, this building made the best of renewable energy sources in order to realize low energy consumption, and the technical reference was provided for promoting application of renewable energy and building energy efficiency in hot-summer and cold-winter zone of China.
2013, 43(5): 44-46,63.
doi: 10.13204/j.gyjz201305010
Abstract:
It was reviewed the progress in research on the solar chimney, focusing on comparative analysis of working principle and practical application of the different solar chimney.And the problems to be solved were proposed based on the solar chimney research.
It was reviewed the progress in research on the solar chimney, focusing on comparative analysis of working principle and practical application of the different solar chimney.And the problems to be solved were proposed based on the solar chimney research.
2013, 43(5): 47-51.
doi: 10.13204/j.gyjz201305011
Abstract:
To solve the weak part of joints with specially shaped column frames, the joint of specially shaped column frames reinforced by steel fiber and the one without reinforcement in the core zone were tested under low cyclic loading.The results in terms of damage characteristic, stirrup strain and concrete strain variation in the core area of joint and shear behavior of joint with specially shaped columns were compared in order to research the mechanical behavior of weak part of joints with specially shaped columns reinforced by steel fiber.It is shown that the damage characteristic of joint reinforced by steel fiber is improved.The stirrup strain of joint reinforced by steel fiber is lower at beginning loading.The stirrup strain in parallel to the direction of shear force in web of joint with specially shaped columns is higher than that of in perpendicular and that of in the flange.The tensile strain for concrete in web and the shear capacity of joint reinforced by steel fiber are higher than that of without reinforcement.
To solve the weak part of joints with specially shaped column frames, the joint of specially shaped column frames reinforced by steel fiber and the one without reinforcement in the core zone were tested under low cyclic loading.The results in terms of damage characteristic, stirrup strain and concrete strain variation in the core area of joint and shear behavior of joint with specially shaped columns were compared in order to research the mechanical behavior of weak part of joints with specially shaped columns reinforced by steel fiber.It is shown that the damage characteristic of joint reinforced by steel fiber is improved.The stirrup strain of joint reinforced by steel fiber is lower at beginning loading.The stirrup strain in parallel to the direction of shear force in web of joint with specially shaped columns is higher than that of in perpendicular and that of in the flange.The tensile strain for concrete in web and the shear capacity of joint reinforced by steel fiber are higher than that of without reinforcement.
2013, 43(5): 52-56,127.
doi: 10.13204/j.gyjz201305012
Abstract:
In order to study the mechanical behavior of reinforced recycled concrete floor-slab, 6 specimens including 3 one-way slabs and 3 two-way slabs were designed, and the recycled coarse aggregate replacement percentage was primarily considered in the test, which were 0%, 50%, 100%.From the test, failure patterns, the loading-displacement curve, the development situation of the deflection in mid-span and the ultimate bearing capacity were obtained, and the influence of the recycled coarse aggregate replacement percentage was analyzed.The existing related standards at home were used to calculate their bearing capacity, compared and analyzed with measured results.The results of study show that the failure modes of the reinforced recycled concrete floor-slab is similar to the normal reinforced concrete floor-slab.Before cracking of concrete, the deflection of the floor-slab is basically the linear increase as the load increases;after cracking of concrete, the deflection's enlargement of the reinforced recycled concrete floor-slab has mutations.The flexural rigidity of the reinforced recycled concrete one-way floor-slab is better than the normal reinforced concrete one-way floor-slab, but the flexural rigidity of the two-way floor-slab is opposite.Compared with the normal reinforced concrete floor-slab, the reinforced recycled concrete floor-slab has the similar cracking bearing capacity, and a higher ultimate bearing capacity.The results can provide reference and basic for further research and application of the reinforced recycled concrete slab component.
In order to study the mechanical behavior of reinforced recycled concrete floor-slab, 6 specimens including 3 one-way slabs and 3 two-way slabs were designed, and the recycled coarse aggregate replacement percentage was primarily considered in the test, which were 0%, 50%, 100%.From the test, failure patterns, the loading-displacement curve, the development situation of the deflection in mid-span and the ultimate bearing capacity were obtained, and the influence of the recycled coarse aggregate replacement percentage was analyzed.The existing related standards at home were used to calculate their bearing capacity, compared and analyzed with measured results.The results of study show that the failure modes of the reinforced recycled concrete floor-slab is similar to the normal reinforced concrete floor-slab.Before cracking of concrete, the deflection of the floor-slab is basically the linear increase as the load increases;after cracking of concrete, the deflection's enlargement of the reinforced recycled concrete floor-slab has mutations.The flexural rigidity of the reinforced recycled concrete one-way floor-slab is better than the normal reinforced concrete one-way floor-slab, but the flexural rigidity of the two-way floor-slab is opposite.Compared with the normal reinforced concrete floor-slab, the reinforced recycled concrete floor-slab has the similar cracking bearing capacity, and a higher ultimate bearing capacity.The results can provide reference and basic for further research and application of the reinforced recycled concrete slab component.
2013, 43(5): 57-63.
doi: 10.13204/j.gyjz201305013
Abstract:
The reinforced concrete beams corroded rapidly by sulfate salt and chloride through the accelerated corrosion method, the destruction shape, ductility, shear carrying capacity of the beams were studied under different corrosion degree.It can be seen that from the experimental results, when the test load of corroded beams reach the ultimate load, the P-w course became steep.The shear cracking time of test beams were more and more latter.When =2.22, the point where the compared shear cracking load from increase to decrease was 1.914, and when =1.39, the point was 2.335.The shear bearing capacity of the beams first increase then drop with the corrosion degrees increase, when =2.22, the increase ratio of the ultimate load reach 27.92 percent, and which was 34.47 percent when =1.39.Based on the experimental results analysis, the prediction models for cracking load and ultimate load and ductility of the corroded beams with different corroded degree were founded.Which provided reliable basis for structural design and structure reinforcement.
The reinforced concrete beams corroded rapidly by sulfate salt and chloride through the accelerated corrosion method, the destruction shape, ductility, shear carrying capacity of the beams were studied under different corrosion degree.It can be seen that from the experimental results, when the test load of corroded beams reach the ultimate load, the P-w course became steep.The shear cracking time of test beams were more and more latter.When =2.22, the point where the compared shear cracking load from increase to decrease was 1.914, and when =1.39, the point was 2.335.The shear bearing capacity of the beams first increase then drop with the corrosion degrees increase, when =2.22, the increase ratio of the ultimate load reach 27.92 percent, and which was 34.47 percent when =1.39.Based on the experimental results analysis, the prediction models for cracking load and ultimate load and ductility of the corroded beams with different corroded degree were founded.Which provided reliable basis for structural design and structure reinforcement.
2013, 43(5): 64-67.
doi: 10.13204/j.gyjz201305014
Abstract:
Based on the crack widths of normal sections of recycled concrete beams under short term loading, the similarities and differences between normal concrete and recycled concrete were compared.It was focused on the crack developing mechanism and width influencing factors of recycled concrete crack.The expression of flexural crack width of recycled concrete beams was presented based on the bond-slip theory and the experiments result.The results showed that the recycled aggregate replacing rate was the extraessential factor of recycled concrete crack, and high discreteness was the main features.The calculation precision of the crack width formula was proved sufficient to meet the demand of design by the test results.
Based on the crack widths of normal sections of recycled concrete beams under short term loading, the similarities and differences between normal concrete and recycled concrete were compared.It was focused on the crack developing mechanism and width influencing factors of recycled concrete crack.The expression of flexural crack width of recycled concrete beams was presented based on the bond-slip theory and the experiments result.The results showed that the recycled aggregate replacing rate was the extraessential factor of recycled concrete crack, and high discreteness was the main features.The calculation precision of the crack width formula was proved sufficient to meet the demand of design by the test results.
2013, 43(5): 68-72.
doi: 10.13204/j.gyjz201305015
Abstract:
In order to control the catastrophe problem of eccentric structure caused by the coupling vibration of torsion under the action of the earthquake effectively, based on the theory analysis and numerical calculation, the motion equation of the coupling vibration of torsion under the action of the earthquake was built, through investigating the control effect of viscous damper for eccentric structure torsion coupling vibration, it was made a comparative analysis of seismic response of the eccentric structure with viscous dampers arranged by four schemes, and also quantified the influence of the combined protection of the viscous damper and steel support on the damping effect of the eccentric structure.The results of the study show that the maximum displacement and the displacement angle of layers of the eccentric structure with the viscous damper can be controlled effectively under the double action of earthquake;the torsion can be controlled effectively with the herringbone arrangement of viscous damper under the action of multiple earthquake, the control effect of different arrangement is basically the same under the action of rare earthquake, the results can provide reference for the vibration control of torsional effect of similar eccentric structures under the action of earthquake.
In order to control the catastrophe problem of eccentric structure caused by the coupling vibration of torsion under the action of the earthquake effectively, based on the theory analysis and numerical calculation, the motion equation of the coupling vibration of torsion under the action of the earthquake was built, through investigating the control effect of viscous damper for eccentric structure torsion coupling vibration, it was made a comparative analysis of seismic response of the eccentric structure with viscous dampers arranged by four schemes, and also quantified the influence of the combined protection of the viscous damper and steel support on the damping effect of the eccentric structure.The results of the study show that the maximum displacement and the displacement angle of layers of the eccentric structure with the viscous damper can be controlled effectively under the double action of earthquake;the torsion can be controlled effectively with the herringbone arrangement of viscous damper under the action of multiple earthquake, the control effect of different arrangement is basically the same under the action of rare earthquake, the results can provide reference for the vibration control of torsional effect of similar eccentric structures under the action of earthquake.
2013, 43(5): 73-78.
doi: 10.13204/j.gyjz201305016
Abstract:
The systematic bolts are often arranged in the soft rock tunnel arch, but their efficacy is different in the different geological conditions and support patterns.The researches on the efficacy of the systematic bolts in the arch of soft rock underwater highway tunnel by the shallow mining method were very rare.Therefore, as an example of Liuyanghe tunnel which was constructed by the shallow mining method in Changsha, the systematic study on tunnel arch systematic bolt with respect to axial force, internal force of primary liner, safety factor of digging and the effects on bolt by groundwater seepage to soft rock were performed by the theoretical analysis, the numerical simulation, and the field test.The results showed that the efficacy of the arch systematic anchor bolts of the Liuyanghe tunnel, under soft rock geologic environment, was not significant and their actions were less.It was suggested that the foot anchoring bolts were installed in shaped steel of upper bench, and the arch systematic bolts could be cancelled.The research results were applied in practice, which had significant benefits.
The systematic bolts are often arranged in the soft rock tunnel arch, but their efficacy is different in the different geological conditions and support patterns.The researches on the efficacy of the systematic bolts in the arch of soft rock underwater highway tunnel by the shallow mining method were very rare.Therefore, as an example of Liuyanghe tunnel which was constructed by the shallow mining method in Changsha, the systematic study on tunnel arch systematic bolt with respect to axial force, internal force of primary liner, safety factor of digging and the effects on bolt by groundwater seepage to soft rock were performed by the theoretical analysis, the numerical simulation, and the field test.The results showed that the efficacy of the arch systematic anchor bolts of the Liuyanghe tunnel, under soft rock geologic environment, was not significant and their actions were less.It was suggested that the foot anchoring bolts were installed in shaped steel of upper bench, and the arch systematic bolts could be cancelled.The research results were applied in practice, which had significant benefits.
2013, 43(5): 79-85.
doi: 10.13204/j.gyjz201305017
Abstract:
Firstly, the settlement governing equation was founded based on Winkler foundation model by assuming the soil and the pile kept elastic contact.Secondly, the shearing deformation method was used to calculate the soil settlement transfer factor.Then the pile-pile interaction was analyzed by applying the soil settlement caused by active loaded pile to the passive pile in pile groups.Finally, the finite difference method was used to analyze vertical response of pile groups in non-homogeneous soils.The validity of the proposed approach was verified through comparisons with some published solutions for single piles and pile groups in homogeneous and non-homogeneous soils.Good agreement was obtained in general.
Firstly, the settlement governing equation was founded based on Winkler foundation model by assuming the soil and the pile kept elastic contact.Secondly, the shearing deformation method was used to calculate the soil settlement transfer factor.Then the pile-pile interaction was analyzed by applying the soil settlement caused by active loaded pile to the passive pile in pile groups.Finally, the finite difference method was used to analyze vertical response of pile groups in non-homogeneous soils.The validity of the proposed approach was verified through comparisons with some published solutions for single piles and pile groups in homogeneous and non-homogeneous soils.Good agreement was obtained in general.
2013, 43(5): 86-89.
doi: 10.13204/j.gyjz201305018
Abstract:
Based on the geotechnical experiment results of over 100 samples for soft soil of the lakeshore new distract in Hefei, the correlation equations between each index were obtained by regression analysis of the correlation analysis of all kinds of the physical and mechanical parameters using MATLAB.The results showed that the lakeshore new distract soft clay had typical features like high water content, large void ratio, high compressibility and low shear strength.There was an excellent linear relation between void ratio and natural water content, and compressibility and natural water content, bulk density and natural water content, and compressibility and void ratio;there was non-linear relation between natural water content and cohesion, and natural water content and internal friction angle.
Based on the geotechnical experiment results of over 100 samples for soft soil of the lakeshore new distract in Hefei, the correlation equations between each index were obtained by regression analysis of the correlation analysis of all kinds of the physical and mechanical parameters using MATLAB.The results showed that the lakeshore new distract soft clay had typical features like high water content, large void ratio, high compressibility and low shear strength.There was an excellent linear relation between void ratio and natural water content, and compressibility and natural water content, bulk density and natural water content, and compressibility and void ratio;there was non-linear relation between natural water content and cohesion, and natural water content and internal friction angle.
2013, 43(5): 90-93.
doi: 10.13204/j.gyjz201305019
Abstract:
Geofabric-composite bolt is a new anchoring reinforcement structure used in cataclasite.A landslide control project was used as a platform to carry out pull-out test of two sorts an chorsfull length bonded and prestressed anchors, to verify the feasibility of using geofabric-composite bolt to strengthen cataclasite.The field test results showed that geofabric-composite bolt could solve the problem of grouting-mud leakage in cataclasite.The data regression analysis showed that reinforced effect and ballooning effect of geofabric could adjust the interface stress between anchoring body and cataclasite and the pollout force of the anchoring system was improved.
Geofabric-composite bolt is a new anchoring reinforcement structure used in cataclasite.A landslide control project was used as a platform to carry out pull-out test of two sorts an chorsfull length bonded and prestressed anchors, to verify the feasibility of using geofabric-composite bolt to strengthen cataclasite.The field test results showed that geofabric-composite bolt could solve the problem of grouting-mud leakage in cataclasite.The data regression analysis showed that reinforced effect and ballooning effect of geofabric could adjust the interface stress between anchoring body and cataclasite and the pollout force of the anchoring system was improved.
2013, 43(5): 94-98.
doi: 10.13204/j.gyjz201305020
Abstract:
The composite masonry of thermal-insulating lightweight concrete hollow block is a new type of structure with composite polystyrene(EPS) soil as its inner core and the lightweight concrete block as its external mould, because it makes the heat preservation and antiseism as a whole, so it suits to town building.In this paper, based on the experiment of 9 groups and 27 shear specimens, the laws of anti-shearing intensity and shear failure mechanism of the composite block masonry were analysed, it was analyzed the effects of different mixture proportions of inner core strength, different grouting ratio and different mortar strength on the shearing strength of composite block masonry.Meanwhile 1 group of shear specimens of baked brick and concrete perforated brick were made to compared with the new composite block;the results show that inner core strength is a major influence factor for masonry shearing strength, and mortar strength is weak for masonry shearing strength, at the same time, inner core strength is about 71% contribution for masonry shearing strength.In the end, the shearing intensity of the composite block masonry was higher than the soil brick and concrete porous brick.
The composite masonry of thermal-insulating lightweight concrete hollow block is a new type of structure with composite polystyrene(EPS) soil as its inner core and the lightweight concrete block as its external mould, because it makes the heat preservation and antiseism as a whole, so it suits to town building.In this paper, based on the experiment of 9 groups and 27 shear specimens, the laws of anti-shearing intensity and shear failure mechanism of the composite block masonry were analysed, it was analyzed the effects of different mixture proportions of inner core strength, different grouting ratio and different mortar strength on the shearing strength of composite block masonry.Meanwhile 1 group of shear specimens of baked brick and concrete perforated brick were made to compared with the new composite block;the results show that inner core strength is a major influence factor for masonry shearing strength, and mortar strength is weak for masonry shearing strength, at the same time, inner core strength is about 71% contribution for masonry shearing strength.In the end, the shearing intensity of the composite block masonry was higher than the soil brick and concrete porous brick.
2013, 43(5): 99-102,98.
doi: 10.13204/j.gyjz201305021
Abstract:
The 1D and 2D carbonations of high performance concrete are studied under different fly ash proportion(0%, 20%, 40%, 60%) and different ratio of bending load(0.20, 0.35, 0.50, 0.65, 0.80).The test method of 2D carbonation under loading is built;The interaction coefficient of 2D carbonation is defined.The influence of different bending load ratio on interaction coefficient is studied.The experiment indicates that carbonation depth of 1D and 2D are increased with the raising ratio of bending load.During the carbonation of 28 d(corresponding to nature carbonation of 50 years), the 1D and 2D carbonation depth under 0.8 ratio of bending load are 1.61 times and 1.39 times as compared to 0 ratio of bending load.At the same time, the depths of carbonation subject to the exponential function of bending load ratio.The 2D carbonation of concrete has an obvious interaction coefficient.The 2D interaction coefficient with load is much smaller than the interaction coefficient without load.And with the increase of stress ratio, the value of interaction coefficient trends to decrease.The research on the 1D and 2D carbonations of concrete under bending load possesses the real meaning to the structure durability and life prediction of concrete.
The 1D and 2D carbonations of high performance concrete are studied under different fly ash proportion(0%, 20%, 40%, 60%) and different ratio of bending load(0.20, 0.35, 0.50, 0.65, 0.80).The test method of 2D carbonation under loading is built;The interaction coefficient of 2D carbonation is defined.The influence of different bending load ratio on interaction coefficient is studied.The experiment indicates that carbonation depth of 1D and 2D are increased with the raising ratio of bending load.During the carbonation of 28 d(corresponding to nature carbonation of 50 years), the 1D and 2D carbonation depth under 0.8 ratio of bending load are 1.61 times and 1.39 times as compared to 0 ratio of bending load.At the same time, the depths of carbonation subject to the exponential function of bending load ratio.The 2D carbonation of concrete has an obvious interaction coefficient.The 2D interaction coefficient with load is much smaller than the interaction coefficient without load.And with the increase of stress ratio, the value of interaction coefficient trends to decrease.The research on the 1D and 2D carbonations of concrete under bending load possesses the real meaning to the structure durability and life prediction of concrete.
2013, 43(5): 103-107.
doi: 10.13204/j.gyjz201305022
Abstract:
It was reviewed briefly the development course of the spatial structures in China in the last 30 years;it was particularly summarized the development and use of the spatial structures, especially spatial grid structures(grid frames, reticulated shells, and some new types of grid structures, such as one-way and two-way beam strings, suspen dome and cable dome etc) in China in the last 10 years.Finally, it was expounded the problems during the development of the spatial grid structures, as well as the developing trend in the future.
It was reviewed briefly the development course of the spatial structures in China in the last 30 years;it was particularly summarized the development and use of the spatial structures, especially spatial grid structures(grid frames, reticulated shells, and some new types of grid structures, such as one-way and two-way beam strings, suspen dome and cable dome etc) in China in the last 10 years.Finally, it was expounded the problems during the development of the spatial grid structures, as well as the developing trend in the future.
2013, 43(5): 108-114.
doi: 10.13204/j.gyjz201305023
Abstract:
System performance factors for base shear determination in various codes were analyzed.In the USA, it includes overstrength factors of both the material and the structural system and the ductility, in EC 8 it contains the structural overstrength and the ductility, in Japan and China, it reflects only the ductility.Because in Japan a load factor of 1.4 is introduced, it has the biggest earthquake forces for structural design.This paper provided also detailed comments on the relations between the drift under the design seismic action and the drift under medium earthquake, and it is found that the formula in EC 8 is in consistent with its philosophy for determining its seismic action, but not without any problem.A new derivation is presented for the relation between the elastic-plastic drift and the elastic drift under design earthquake.
System performance factors for base shear determination in various codes were analyzed.In the USA, it includes overstrength factors of both the material and the structural system and the ductility, in EC 8 it contains the structural overstrength and the ductility, in Japan and China, it reflects only the ductility.Because in Japan a load factor of 1.4 is introduced, it has the biggest earthquake forces for structural design.This paper provided also detailed comments on the relations between the drift under the design seismic action and the drift under medium earthquake, and it is found that the formula in EC 8 is in consistent with its philosophy for determining its seismic action, but not without any problem.A new derivation is presented for the relation between the elastic-plastic drift and the elastic drift under design earthquake.
2013, 43(5): 115-117,156.
doi: 10.13204/j.gyjz201305024
Abstract:
Newly issued Concrete Structural Design Code(GB 500102010) proposes a bond-slip constitutive relation between steel bars and concrete.In order to fully explore its applicability, two types of numerical models considering and not considering the bond-slip relationship were established by the software DIANA.Based on which, the cracking loads, the load-deflection curves, the crack distribution patterns of the beams were compared and analyzed between simulation and experimental results.It is shown that the analysis results with the bond-slip constitutive relation are better than that not considering the bond-slip relationship.The bond-slip constitutive relation proposed by the new code can better reflect the coordinated working performance between concrete and steel, and can help improve the accuracy of numerical analysis.
Newly issued Concrete Structural Design Code(GB 500102010) proposes a bond-slip constitutive relation between steel bars and concrete.In order to fully explore its applicability, two types of numerical models considering and not considering the bond-slip relationship were established by the software DIANA.Based on which, the cracking loads, the load-deflection curves, the crack distribution patterns of the beams were compared and analyzed between simulation and experimental results.It is shown that the analysis results with the bond-slip constitutive relation are better than that not considering the bond-slip relationship.The bond-slip constitutive relation proposed by the new code can better reflect the coordinated working performance between concrete and steel, and can help improve the accuracy of numerical analysis.
2013, 43(5): 118-121.
doi: 10.13204/j.gyjz201305025
Abstract:
Basic hypothesis and nonlinear finite element equations of static analysis for rigid bracing dome were given.The cable sag of rigid bracing dome was discussing, static characteristics of rigid bracing dome and cable dome were compared, the influence of structure's parameters(as initial prestress, span, rise, etc.) was discussed.Analysis of example demonstrated that the impact of cable sag could be negligible for rigid bracing dome, the whole stiffness of rigid bracing dome was greater than that of a cable dome, and the force behavior of ridge cable was in full play.
Basic hypothesis and nonlinear finite element equations of static analysis for rigid bracing dome were given.The cable sag of rigid bracing dome was discussing, static characteristics of rigid bracing dome and cable dome were compared, the influence of structure's parameters(as initial prestress, span, rise, etc.) was discussed.Analysis of example demonstrated that the impact of cable sag could be negligible for rigid bracing dome, the whole stiffness of rigid bracing dome was greater than that of a cable dome, and the force behavior of ridge cable was in full play.
2013, 43(5): 122-127.
doi: 10.13204/j.gyjz201305026
Abstract:
A practical theoretical approach was presented to calculate M-r relationship of self-centering steel connection with bolted top and seat angles.Based on the research of the connection failure mechanism, connection bearing capacity was deduced by component method.Using the Eurocode 3 and Kishi-Chen function model, it was obtained the connection M-r relationship and presented the design principles at each stage.The theoretical model calculation results, finite element analysis results and some experiment results were compared, the validity of the method was proved.In finite element analysis, the connection reflected better self-centering performance.The stresses of column web in the vicinity of the rotation center concentrated significantly, and it should be reinforced with stiffening rib and plate to ensure the local stability of elements.
A practical theoretical approach was presented to calculate M-r relationship of self-centering steel connection with bolted top and seat angles.Based on the research of the connection failure mechanism, connection bearing capacity was deduced by component method.Using the Eurocode 3 and Kishi-Chen function model, it was obtained the connection M-r relationship and presented the design principles at each stage.The theoretical model calculation results, finite element analysis results and some experiment results were compared, the validity of the method was proved.In finite element analysis, the connection reflected better self-centering performance.The stresses of column web in the vicinity of the rotation center concentrated significantly, and it should be reinforced with stiffening rib and plate to ensure the local stability of elements.
2013, 43(5): 128-131.
doi: 10.13204/j.gyjz201305027
Abstract:
Six rectangular concrete filled double skin steel tubes(RCFDST) and one rectangular concrete filled steel tube were tested under axial compressive load.The changes of test parameters were length-width ratios of inner and outer steel tubes.The test results showed that compared specimens with the same inner tubes, the axial bearing capacity of specimens with larger size of outer steel tube was higher.Due to reducing area of concrete and local buckling of the inner tube, the axial bearing capacity of specimen declines slightly with the increasing of size of inner steel tubes compared specimens with the same outer tube.The axial bearing capacity of concrete filled steel tube was higher than that of concrete filled double skin steel tubes.Load-deformation relationship curves of rectangular concrete filled double skin steel tubes subjected to axial compression were analyzed by finite element software ABAQUS, the calculated results were in good agreement with those of tests.
Six rectangular concrete filled double skin steel tubes(RCFDST) and one rectangular concrete filled steel tube were tested under axial compressive load.The changes of test parameters were length-width ratios of inner and outer steel tubes.The test results showed that compared specimens with the same inner tubes, the axial bearing capacity of specimens with larger size of outer steel tube was higher.Due to reducing area of concrete and local buckling of the inner tube, the axial bearing capacity of specimen declines slightly with the increasing of size of inner steel tubes compared specimens with the same outer tube.The axial bearing capacity of concrete filled steel tube was higher than that of concrete filled double skin steel tubes.Load-deformation relationship curves of rectangular concrete filled double skin steel tubes subjected to axial compression were analyzed by finite element software ABAQUS, the calculated results were in good agreement with those of tests.
2013, 43(5): 132-136,143.
doi: 10.13204/j.gyjz201305028
Abstract:
Nonlinear analysis of member sections play an important role in structural seismic investigation.Based on the triaxial-force feature of the steel, a constitutive model of steel suitable for concrete-filled square steel tubular beam-column was proposed for establishing moment-curvature envelop curve, meanwhile hoop tension stress was considered in this model;a fiber-based numerical model program for beam-columns subjected to bending and axial load was developed with the proposed steel constitutive model and the existing confined concrete constitutive model.The influence on moment-curvature envelop curve of concrete-filled square steel tubular beam-column from those parameters, including steel ratio, steel yield strength, concrete strength and axial compression ratio, was studied respectively.The trilinear envelop curve model of concrete-filled square steel tubular beam-column was proposed by the analysis of yield moment and ultimate bending moment, and this model could be used for the structural dynamic analysis of projects.
Nonlinear analysis of member sections play an important role in structural seismic investigation.Based on the triaxial-force feature of the steel, a constitutive model of steel suitable for concrete-filled square steel tubular beam-column was proposed for establishing moment-curvature envelop curve, meanwhile hoop tension stress was considered in this model;a fiber-based numerical model program for beam-columns subjected to bending and axial load was developed with the proposed steel constitutive model and the existing confined concrete constitutive model.The influence on moment-curvature envelop curve of concrete-filled square steel tubular beam-column from those parameters, including steel ratio, steel yield strength, concrete strength and axial compression ratio, was studied respectively.The trilinear envelop curve model of concrete-filled square steel tubular beam-column was proposed by the analysis of yield moment and ultimate bending moment, and this model could be used for the structural dynamic analysis of projects.
2013, 43(5): 137-143.
doi: 10.13204/j.gyjz201305029
Abstract:
Based on twin shear unified strength theory, the contributions of steel tube, web, concrete in the steel tube and cavity and constrains provided by steel tube and web were considered.Whilst considering the influence of slenderness ratio, eccentricity ratio and initial stress for dumbbell shaped cross-section, the ultimate bearing capacity formula for dumbbell shaped concrete-filled steel tubular column was developed by two methods, and the impacts of some relevant parameters were analyzed as well.Through comparing the results of proposed formula with that of experiments and relevant literatures, the rationality of proposed formula was proved.
Based on twin shear unified strength theory, the contributions of steel tube, web, concrete in the steel tube and cavity and constrains provided by steel tube and web were considered.Whilst considering the influence of slenderness ratio, eccentricity ratio and initial stress for dumbbell shaped cross-section, the ultimate bearing capacity formula for dumbbell shaped concrete-filled steel tubular column was developed by two methods, and the impacts of some relevant parameters were analyzed as well.Through comparing the results of proposed formula with that of experiments and relevant literatures, the rationality of proposed formula was proved.
2013, 43(5): 144-147.
doi: 10.13204/j.gyjz201305030
Abstract:
Through the experiment of the bending capacity of the corroded reinforced concrete beams before and after strengthened with CFRP sheets, the influence of the secondary load and corrosion on the load-carrying capacity and rigidity of reinforced concrete beams was discussed.The results of the study show that the load-carrying capacity and rigidity of corroded reinforced concrete beams with CFRP sheets have been improved in different degrees.The lagged strain caused by the secondary load would influence the effect of its high tensile strength.And the change of mechanical properties of the corroded reinforced concrete beams reduced the bending capacity of beams strengthened with CFRP sheets.Based on the mechanical properties of the corroded reinforced concrete beams, the numerical simulation technology of the whole bending process of the corroded reinforced concrete beams strengthened with CFRP sheets was established.The good conformity of the calculation results and the experimental results can provide reference for the reinforcement design of the corroded reinforced concrete beams in the future.
Through the experiment of the bending capacity of the corroded reinforced concrete beams before and after strengthened with CFRP sheets, the influence of the secondary load and corrosion on the load-carrying capacity and rigidity of reinforced concrete beams was discussed.The results of the study show that the load-carrying capacity and rigidity of corroded reinforced concrete beams with CFRP sheets have been improved in different degrees.The lagged strain caused by the secondary load would influence the effect of its high tensile strength.And the change of mechanical properties of the corroded reinforced concrete beams reduced the bending capacity of beams strengthened with CFRP sheets.Based on the mechanical properties of the corroded reinforced concrete beams, the numerical simulation technology of the whole bending process of the corroded reinforced concrete beams strengthened with CFRP sheets was established.The good conformity of the calculation results and the experimental results can provide reference for the reinforcement design of the corroded reinforced concrete beams in the future.
2013, 43(5): 148-152.
doi: 10.13204/j.gyjz201305031
Abstract:
The different fatigue life of CFRP strengthened steel beams and unstrengthened ones were compared under medium-high cycle and low stress range fatigue test, and the fitting result of the test was analyzed.It was shown that the fatigue life could be improved by gluing CFRP on the sensitive area of the bottom flange of steel beam.The fatigue life of steel beams with initial fatigue crack could also be restored to the level of undamaged ones by gluing CFRP.
The different fatigue life of CFRP strengthened steel beams and unstrengthened ones were compared under medium-high cycle and low stress range fatigue test, and the fitting result of the test was analyzed.It was shown that the fatigue life could be improved by gluing CFRP on the sensitive area of the bottom flange of steel beam.The fatigue life of steel beams with initial fatigue crack could also be restored to the level of undamaged ones by gluing CFRP.
2013, 43(5): 153-156.
doi: 10.13204/j.gyjz201305032
Abstract:
Under the trend of the development of the times and the requirement of people, architects pay more and more attention to the design of the small city.According to design concept, layout, landscape design, architectural design of new technology healthy and environmental design as well as some details of the design, the paper combines with the project design examples and takes the green energy of small cities as the theme in order to achieve the aim of building the green, healthy, energy-saving and ecological high-quality living environment.
Under the trend of the development of the times and the requirement of people, architects pay more and more attention to the design of the small city.According to design concept, layout, landscape design, architectural design of new technology healthy and environmental design as well as some details of the design, the paper combines with the project design examples and takes the green energy of small cities as the theme in order to achieve the aim of building the green, healthy, energy-saving and ecological high-quality living environment.
2013, 43(5): 157-161.
doi: 10.13204/j.gyjz201305033
Abstract:
City joint is used to describe urban space in the urban study, and it was first put forward as one of the five key elements to representing city's image by famous American architect Kevin Lynch in 1960s.From then on, the diversity of city joint has been emerging due to different understanding of this concept.However, systematic study on city joint is very insufficient at the moment, and the concept of city joint is combed and clarified, and its space domain is investigated, in order to provide a reference to solve current situation problem in the modern urban construction.
City joint is used to describe urban space in the urban study, and it was first put forward as one of the five key elements to representing city's image by famous American architect Kevin Lynch in 1960s.From then on, the diversity of city joint has been emerging due to different understanding of this concept.However, systematic study on city joint is very insufficient at the moment, and the concept of city joint is combed and clarified, and its space domain is investigated, in order to provide a reference to solve current situation problem in the modern urban construction.
