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2011 Vol. 41, No. 12
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2011, 41(12): 1-7.
doi: 10.13204/j.gyjz201112001
Abstract:
A comprehensive review is given to the effects of existing secondary forces on prestressed concrete and steel concrete structures at the use stage and the stage of the limit load.Due to the fact that the mechanical characteristics of a statically indeterminate prestressed concrete structure with redundant constraints are different from those of a continuous beam structure, there are a number of limitations in the theories and methods of computation and recommendations are also proposed for future researches.
A comprehensive review is given to the effects of existing secondary forces on prestressed concrete and steel concrete structures at the use stage and the stage of the limit load.Due to the fact that the mechanical characteristics of a statically indeterminate prestressed concrete structure with redundant constraints are different from those of a continuous beam structure, there are a number of limitations in the theories and methods of computation and recommendations are also proposed for future researches.
2011, 41(12): 8-11.
doi: 10.13204/j.gyjz201112002
Abstract:
With a bearing capacity test on prestressed concrete frame, the frame is simulated by finite element software ABAQUS.The simulation results agree well with the test results.Based on this, three sets of finite element models are set up.By changing the boundary conditions, the analysis is carried out.The results show that the existence of the secondry force reduces the ultimate resisting moment.Under different prestress-degree, reinforcement ratio, tension control stress and initial secondry force, the secondry force is smaller than the initial force with formation of a plastic hinge in the beam end, but its value should be still large.So the effect of the secondary axial force should be considered in calculation of bearing capacity.
With a bearing capacity test on prestressed concrete frame, the frame is simulated by finite element software ABAQUS.The simulation results agree well with the test results.Based on this, three sets of finite element models are set up.By changing the boundary conditions, the analysis is carried out.The results show that the existence of the secondry force reduces the ultimate resisting moment.Under different prestress-degree, reinforcement ratio, tension control stress and initial secondry force, the secondry force is smaller than the initial force with formation of a plastic hinge in the beam end, but its value should be still large.So the effect of the secondary axial force should be considered in calculation of bearing capacity.
2011, 41(12): 12-15.
doi: 10.13204/j.gyjz201112003
Abstract:
In this paper, the prestressed concrete frame beam of the Oriental Sports Center was studied for the background.Through simulation analysis of the three construction schemes, it was obtained the impacts of different construction methods on structural cracking moment, crack width, mid-span deflection and ultimate bearing capacity of the structure.Finally, reasonable construction methods to adjust the secondary internal force of prestressed concrete frame structures are discussed.
In this paper, the prestressed concrete frame beam of the Oriental Sports Center was studied for the background.Through simulation analysis of the three construction schemes, it was obtained the impacts of different construction methods on structural cracking moment, crack width, mid-span deflection and ultimate bearing capacity of the structure.Finally, reasonable construction methods to adjust the secondary internal force of prestressed concrete frame structures are discussed.
2011, 41(12): 16-19.
doi: 10.13204/j.gyjz201112004
Abstract:
Based on the static test of large-scaled prestressed steel concrete frames, the crack resistance of such frame beams was tested and investigated.In this paper, according to theory of reinforced concrete members and the formulas of crack resistance in Code for Design of Concrete Structures(GB 500102002)and code ACI 31805, the formulas of cracking moment considering secondary axial forces were deduced and verified by test results.Conclusion can be drawn as follows: the calculation error of formulas derived from theory of reinforced concrete members is small, generally less than 6%;the error of formulas derived from GB 500102002 is about 10%, which can meet the needs of engineering and simply to be calculated;cracking moment calculated by formulas derived from code ACI 31805 is less than test result, it is unsafe for engineering application.
Based on the static test of large-scaled prestressed steel concrete frames, the crack resistance of such frame beams was tested and investigated.In this paper, according to theory of reinforced concrete members and the formulas of crack resistance in Code for Design of Concrete Structures(GB 500102002)and code ACI 31805, the formulas of cracking moment considering secondary axial forces were deduced and verified by test results.Conclusion can be drawn as follows: the calculation error of formulas derived from theory of reinforced concrete members is small, generally less than 6%;the error of formulas derived from GB 500102002 is about 10%, which can meet the needs of engineering and simply to be calculated;cracking moment calculated by formulas derived from code ACI 31805 is less than test result, it is unsafe for engineering application.
2011, 41(12): 20-23,7.
doi: 10.13204/j.gyjz201112005
Abstract:
The objective of crack width control is to ensure the normal function and durability of a structure.Based on the vertical static test of two prestressed steel reinforced concrete frames, the crack occurrence, development and distribution of prestressed steel reinforced concrete frames were observed and analyzed.The prestressed steel reinforced concrete structure calculation formula of the maximum crack width is put forward, which consideres the impact of the second moment and second axial force and bases on the calculation principle of crack width in current code for design of concrete structure.The concept of formula is clear and the calculated values agree well with the test results.The formula proposed has a certain value of reference for the compilation of Prestressed Concrete Design Code.
The objective of crack width control is to ensure the normal function and durability of a structure.Based on the vertical static test of two prestressed steel reinforced concrete frames, the crack occurrence, development and distribution of prestressed steel reinforced concrete frames were observed and analyzed.The prestressed steel reinforced concrete structure calculation formula of the maximum crack width is put forward, which consideres the impact of the second moment and second axial force and bases on the calculation principle of crack width in current code for design of concrete structure.The concept of formula is clear and the calculated values agree well with the test results.The formula proposed has a certain value of reference for the compilation of Prestressed Concrete Design Code.
2011, 41(12): 24-29.
doi: 10.13204/j.gyjz201112006
Abstract:
Based on the vertical static test of two prestressed steel reinforced concrete frames, two bending capacity calculated methods are put forward, which consider the impact of lateral restraint on prestressed steel reinforced concrete frame beams.One is the improved general superposition method based on the lower limit theorem of plastic theory calculated results and the other is the method based on the basic assumptions of Code for Design of Concrete Structure.The error between the calculated results by the two methods and those of the test is less than 10%, whose degree of agreement is good, the methods can be used in engineering design and have a certain value of reference for the compilation of Prestressed Concrete Design Code.
Based on the vertical static test of two prestressed steel reinforced concrete frames, two bending capacity calculated methods are put forward, which consider the impact of lateral restraint on prestressed steel reinforced concrete frame beams.One is the improved general superposition method based on the lower limit theorem of plastic theory calculated results and the other is the method based on the basic assumptions of Code for Design of Concrete Structure.The error between the calculated results by the two methods and those of the test is less than 10%, whose degree of agreement is good, the methods can be used in engineering design and have a certain value of reference for the compilation of Prestressed Concrete Design Code.
2011, 41(12): 30-33,11.
doi: 10.13204/j.gyjz201112007
Abstract:
In order to study the stiffness of PSRC beam, two prestressed steel reinforced concrete frames ware tested.The text results of the average strains of this sort of beam are basically consistent with the hypothesis of plan section, whose load-deflection curves are close to three-section line.Based on the experiment, it is derived the stiffness formula of the PSRC beam by the stiffness stack method.After comparing the calculation results with test results of deflection.It is believed that this formula can accurately calculates the stiffness of PSRC beam and also a reference for the compilation of the PSRC code.
In order to study the stiffness of PSRC beam, two prestressed steel reinforced concrete frames ware tested.The text results of the average strains of this sort of beam are basically consistent with the hypothesis of plan section, whose load-deflection curves are close to three-section line.Based on the experiment, it is derived the stiffness formula of the PSRC beam by the stiffness stack method.After comparing the calculation results with test results of deflection.It is believed that this formula can accurately calculates the stiffness of PSRC beam and also a reference for the compilation of the PSRC code.
2011, 41(12): 34-38.
doi: 10.13204/j.gyjz201112008
Abstract:
Based on test of two large-scaled PSRC frames, nonlinear analysis is carried out for two tested prestressed steel-concrete frames using finite element ABAQUS.Numerical simulation results and test results are compared.Results show that the nonlinear analysis can simulate exactly the whole process of the test for this kind of structure.Both test results and numerical simulation results indicate that the amplitude modulation value of support moment increases as the degree of prestressing of the PSCF increases when depth of compression zone remains invariant;when the degree of the prestress remains constant, it decreases when depth of compression zone increases.The amplitude modulation value of support moment decreases when effective prestress increases.
Based on test of two large-scaled PSRC frames, nonlinear analysis is carried out for two tested prestressed steel-concrete frames using finite element ABAQUS.Numerical simulation results and test results are compared.Results show that the nonlinear analysis can simulate exactly the whole process of the test for this kind of structure.Both test results and numerical simulation results indicate that the amplitude modulation value of support moment increases as the degree of prestressing of the PSCF increases when depth of compression zone remains invariant;when the degree of the prestress remains constant, it decreases when depth of compression zone increases.The amplitude modulation value of support moment decreases when effective prestress increases.
2011, 41(12): 39-43.
doi: 10.13204/j.gyjz201112009
Abstract:
Pseudo dynamic test was conducted on two-storey double-span post-tensioned precast prestressed concrete model frame.The failure mechanism, deformation properties, rigidity degradation and energy dissipation capacity of the structure under dynamic load was investigated, and the elastic-plastic dynamic analysis of model structure was carried out.The analysis indicated that hysteresis curves and energy dissipation of specimens were good at high loading, and the inelastic rotation could be occurred at beam ends for moment redistribution.The prestressed fabricated connection had enough displacement restoring capacity, which reduced the frame damage in earthquake and could be repaired conveniently.
Pseudo dynamic test was conducted on two-storey double-span post-tensioned precast prestressed concrete model frame.The failure mechanism, deformation properties, rigidity degradation and energy dissipation capacity of the structure under dynamic load was investigated, and the elastic-plastic dynamic analysis of model structure was carried out.The analysis indicated that hysteresis curves and energy dissipation of specimens were good at high loading, and the inelastic rotation could be occurred at beam ends for moment redistribution.The prestressed fabricated connection had enough displacement restoring capacity, which reduced the frame damage in earthquake and could be repaired conveniently.
2011, 41(12): 44-47,38.
doi: 10.13204/j.gyjz201112010
Abstract:
In the modern industry constructions, the original high energy consumption and high pollution design goes against the low-carbon and low-consumption principles.As a matter of fact, recently, it is necessary to consider the construction cost in the whole life cycle of a plant.A set of efficient low-carbon construction methods of the power plant is proposed based on a practical project.As the standard of the plant construction, the specific low-carbon criterion is discussed firstly.Then the design methods are analyzed in detail.Furthermore, a novel concrete coloration technique by reusing the waste rice husk ash is developed to improve the appearance of the plant and reduce the construction costs.At last, from the cost analysis of the plant in whole life cycle, the proposed low-carbon design of power plant is illustrated to be significant of economic benefit as well as environment protection.
In the modern industry constructions, the original high energy consumption and high pollution design goes against the low-carbon and low-consumption principles.As a matter of fact, recently, it is necessary to consider the construction cost in the whole life cycle of a plant.A set of efficient low-carbon construction methods of the power plant is proposed based on a practical project.As the standard of the plant construction, the specific low-carbon criterion is discussed firstly.Then the design methods are analyzed in detail.Furthermore, a novel concrete coloration technique by reusing the waste rice husk ash is developed to improve the appearance of the plant and reduce the construction costs.At last, from the cost analysis of the plant in whole life cycle, the proposed low-carbon design of power plant is illustrated to be significant of economic benefit as well as environment protection.
2011, 41(12): 48-51,15.
doi: 10.13204/j.gyjz201112011
Abstract:
According to the design of industrial park and aseptic workshop of Lirenyuan Sci-Tech Development Co., Ltd in Wuhan, it was expounded the design ideas of an industrial park and it's production buildings, as well as explored its development strategy, pattern and also the implementation strategy.
According to the design of industrial park and aseptic workshop of Lirenyuan Sci-Tech Development Co., Ltd in Wuhan, it was expounded the design ideas of an industrial park and it's production buildings, as well as explored its development strategy, pattern and also the implementation strategy.
2011, 41(12): 52-56.
doi: 10.13204/j.gyjz201112012
Abstract:
Nowadays, the industrial structure adjustment is an important issue for economic development in all countries.It is trend to adjust industrial structure from the national to regional level.By analyzing industrial orientations of Jingxi Industrial park in different plan, the new target is set after comprehensive demonstration.And strategies are proposed to achieve it.These will promote economic and social development and give protection to improve people's quality of material and cultural life.
Nowadays, the industrial structure adjustment is an important issue for economic development in all countries.It is trend to adjust industrial structure from the national to regional level.By analyzing industrial orientations of Jingxi Industrial park in different plan, the new target is set after comprehensive demonstration.And strategies are proposed to achieve it.These will promote economic and social development and give protection to improve people's quality of material and cultural life.
2011, 41(12): 57-59,43.
doi: 10.13204/j.gyjz201112013
Abstract:
Montage is a method of film creation, and also the traditional technique of architectural design.The proposal of an office building focuses on the organization and disposition of interior spaces on the basis of multiple uses.It is attempted to search for a transparent, open and modern civil form of office building, and also seek a balance between order and variety in the structure of interior spaces, incorporating the complexity of functions into the asymmetrical planning pattern.By doing such a theoretical perspective of interior landscape in contrast with the prevailing over expressed vulgar typology can be fabricated.
Montage is a method of film creation, and also the traditional technique of architectural design.The proposal of an office building focuses on the organization and disposition of interior spaces on the basis of multiple uses.It is attempted to search for a transparent, open and modern civil form of office building, and also seek a balance between order and variety in the structure of interior spaces, incorporating the complexity of functions into the asymmetrical planning pattern.By doing such a theoretical perspective of interior landscape in contrast with the prevailing over expressed vulgar typology can be fabricated.
2011, 41(12): 60-64,56.
doi: 10.13204/j.gyjz201112014
Abstract:
In order to facilitate further promotion of the ecological composite wall, the test of an ecological energy-saving composite wall with 1/2 scale under low-frequency cyclic loading is carried on based on the large amounts of the previous experiments of the group, the seismic performances of the wall, which is conducted by changing the construction technology based on the ecological nergy-saving composite wall, such as the bearing capacity, stiffness and displacement ductility are studied and compared with the previous standard multi-ribbed ecological composite walls.Test results and theoretical research show that the bearing capacity and stiffness of the site building stiffening ribs ecological composite wall are both lower than the previous standard multi-ribbed ecological composite walls.However, by applying the site building stiffening ribs, it can avoids some engineering problems of the new rural construction in remote areas, such as site lifting and transportation, which meets the design requirements.At the same time, it can shorten the construction period, reduce the cost and solve the cracking of traditional masonry structures easily.Therefore, the site building stiffening ribs ecological composite wall has broad application prospects.
In order to facilitate further promotion of the ecological composite wall, the test of an ecological energy-saving composite wall with 1/2 scale under low-frequency cyclic loading is carried on based on the large amounts of the previous experiments of the group, the seismic performances of the wall, which is conducted by changing the construction technology based on the ecological nergy-saving composite wall, such as the bearing capacity, stiffness and displacement ductility are studied and compared with the previous standard multi-ribbed ecological composite walls.Test results and theoretical research show that the bearing capacity and stiffness of the site building stiffening ribs ecological composite wall are both lower than the previous standard multi-ribbed ecological composite walls.However, by applying the site building stiffening ribs, it can avoids some engineering problems of the new rural construction in remote areas, such as site lifting and transportation, which meets the design requirements.At the same time, it can shorten the construction period, reduce the cost and solve the cracking of traditional masonry structures easily.Therefore, the site building stiffening ribs ecological composite wall has broad application prospects.
2011, 41(12): 65-70.
doi: 10.13204/j.gyjz201112015
Abstract:
Based on the shaking table tests, it was done the static test of these columns under low cyclic loading, which were compared with specimens which were not affected by the earthquake.Through calculation and analysis of cracks mechanism, P- hysteresis and the skeleton hysteresis curve, energy dissipation and carrying capacity etc, it was got the long-term performance of the early columns having different degrees of damages.
Based on the shaking table tests, it was done the static test of these columns under low cyclic loading, which were compared with specimens which were not affected by the earthquake.Through calculation and analysis of cracks mechanism, P- hysteresis and the skeleton hysteresis curve, energy dissipation and carrying capacity etc, it was got the long-term performance of the early columns having different degrees of damages.
2011, 41(12): 71-74.
doi: 10.13204/j.gyjz201112016
Abstract:
In the paper, a new type of load-bearing thermal insulation composite concrete small hollow block masonry with different reinforcement detailing were studied by the tests under axial and eccentric compressive loads, focusing on the impact of insulating layer, as well as the arrangement of horizontal reinforcement on the wall compressive bearing capacity and deformation performance.Loading and damage characteristics of the wall subjected to different compressive states were analyzed.Studies have shown that the level of steel mesh covered with even more help to make insulation layer work together with the main load-bearing building blocks, and the insulating layer can enhance the bearing capacity of the wall, and the measured bearing capacity of composite block wall is higher than the value of standardized formula.
In the paper, a new type of load-bearing thermal insulation composite concrete small hollow block masonry with different reinforcement detailing were studied by the tests under axial and eccentric compressive loads, focusing on the impact of insulating layer, as well as the arrangement of horizontal reinforcement on the wall compressive bearing capacity and deformation performance.Loading and damage characteristics of the wall subjected to different compressive states were analyzed.Studies have shown that the level of steel mesh covered with even more help to make insulation layer work together with the main load-bearing building blocks, and the insulating layer can enhance the bearing capacity of the wall, and the measured bearing capacity of composite block wall is higher than the value of standardized formula.
2011, 41(12): 75-78,83.
doi: 10.13204/j.gyjz201112017
Abstract:
By using field testing and finite element method, structures' responses of floors respectively reinforced by cold-rolled spiral steel bars, plain round bars and cold rolled ribbed steel bars were compared under the normal working loads, which were floor's craze status, deflection and strain.The results show that the performance of the floor reinforced by cold-rolled spiral steel wires is the best among three floors, and what's more, it is economical and feasible to choose cold-rolled spiral steel bars as stressed steel bars for building engineering.
By using field testing and finite element method, structures' responses of floors respectively reinforced by cold-rolled spiral steel bars, plain round bars and cold rolled ribbed steel bars were compared under the normal working loads, which were floor's craze status, deflection and strain.The results show that the performance of the floor reinforced by cold-rolled spiral steel wires is the best among three floors, and what's more, it is economical and feasible to choose cold-rolled spiral steel bars as stressed steel bars for building engineering.
2011, 41(12): 79-83.
doi: 10.13204/j.gyjz201112018
Abstract:
Capacity spectrum method was adopted to perform nonlinear static seismic response(pushover) analysis for eco-composite wall structure with grouped pile foundation resting on natural foundation soil.The substructure technique was adopted to simulate pile group with a group of springs, the grouped pile stiffness was determined with Davies method.According to the rigid frame-equivalent brace model, the Pushover model of soil-pile-structure interaction system was established.The differences of the results of two models under different earthquake intensities were discussed.The culated results show that in frequent earthquake conditions, structure performance point vertex displacement Un(rigid foundation) Un(interaction);while in rare earthquake conditions, There is the Un(rigid foundation) Un(interaction).When considering soil pile structure interaction, under the same seismic intensity conditions the base shear at performance point of the is increased as compared with a rigid foundation.
Capacity spectrum method was adopted to perform nonlinear static seismic response(pushover) analysis for eco-composite wall structure with grouped pile foundation resting on natural foundation soil.The substructure technique was adopted to simulate pile group with a group of springs, the grouped pile stiffness was determined with Davies method.According to the rigid frame-equivalent brace model, the Pushover model of soil-pile-structure interaction system was established.The differences of the results of two models under different earthquake intensities were discussed.The culated results show that in frequent earthquake conditions, structure performance point vertex displacement Un(rigid foundation) Un(interaction);while in rare earthquake conditions, There is the Un(rigid foundation) Un(interaction).When considering soil pile structure interaction, under the same seismic intensity conditions the base shear at performance point of the is increased as compared with a rigid foundation.
2011, 41(12): 84-87,70.
doi: 10.13204/j.gyjz201112019
Abstract:
This paper carried out the experimental study on road engineering property of compaction phyllite material abandoning in the southwest area of China.The experiment results indicated that the broken structure phyllite pieces played a leading role in changes of particle gradation of compacted material;and the phyllite mixture was easy to be compacted, but the compaction had noteworthy deformation characteristics.The phyllite material abandoning had highly decentralized characteristics and was extremely collapsed in water.Based on the above characteristics, the effective measures should be carried out, when phyllite material abandoning was to be used to embankment fill and the characteristics should be studied further.
This paper carried out the experimental study on road engineering property of compaction phyllite material abandoning in the southwest area of China.The experiment results indicated that the broken structure phyllite pieces played a leading role in changes of particle gradation of compacted material;and the phyllite mixture was easy to be compacted, but the compaction had noteworthy deformation characteristics.The phyllite material abandoning had highly decentralized characteristics and was extremely collapsed in water.Based on the above characteristics, the effective measures should be carried out, when phyllite material abandoning was to be used to embankment fill and the characteristics should be studied further.
2011, 41(12): 88-91.
doi: 10.13204/j.gyjz201112020
Abstract:
Pile-anchor system is widely applied in slope-reinforcing engineering.The study on dynamic response of the soil slope supported with pile-anchor system subjected to earthquake wave is very important to finding out failure mechanism and seismic character of the slope, and guiding slope reinforcing design.A vertical soil slope model with pile-anchor system was established, The stresses and strains, moments and shear forces of the pile and anchor axial force were obtained.By applying seismic wave dynamic analysis of the slope applied with piles and anchors was performed, and the velocities, displacements, soil pressures, tension stresses of the slope surface, shear forces and moments of the piles, and anchor axial forces dynamic response were obtained.Moreover, pile-anchor system dynamic character was displayed, the results showed that pile-anchor system could validly control the deformation, slope stability and tension stresses on slope top surface, and had very good anti-earthquake capability.
Pile-anchor system is widely applied in slope-reinforcing engineering.The study on dynamic response of the soil slope supported with pile-anchor system subjected to earthquake wave is very important to finding out failure mechanism and seismic character of the slope, and guiding slope reinforcing design.A vertical soil slope model with pile-anchor system was established, The stresses and strains, moments and shear forces of the pile and anchor axial force were obtained.By applying seismic wave dynamic analysis of the slope applied with piles and anchors was performed, and the velocities, displacements, soil pressures, tension stresses of the slope surface, shear forces and moments of the piles, and anchor axial forces dynamic response were obtained.Moreover, pile-anchor system dynamic character was displayed, the results showed that pile-anchor system could validly control the deformation, slope stability and tension stresses on slope top surface, and had very good anti-earthquake capability.
2011, 41(12): 92-97,29.
doi: 10.13204/j.gyjz201112021
Abstract:
In the design of soil nailing, the spacing, the force and the length of the nails are estimated according to the lateral earth pressure.So the rational value and distribution of lateral earth pressure has a significant influence on the design.A three dimensional nonlinear finite element model was employed to analyze the behaviors of soil nailing, in which the characteristics of soil under excavation was considered.The analysis results showed: the distribution of lateral earth pressure on soil nailing was different from that on rigid retaining wall, and the sum of lateral earth pressure varied from the active earth pressure and the static earth pressure;the lateral earth pressure suggested by present code was not in accordance with the results by finite element method;and the degree of agreement between the reduction coefficients method for non-vertical excavation derived by different methods and the results by finite element method was not the same for different soil.
In the design of soil nailing, the spacing, the force and the length of the nails are estimated according to the lateral earth pressure.So the rational value and distribution of lateral earth pressure has a significant influence on the design.A three dimensional nonlinear finite element model was employed to analyze the behaviors of soil nailing, in which the characteristics of soil under excavation was considered.The analysis results showed: the distribution of lateral earth pressure on soil nailing was different from that on rigid retaining wall, and the sum of lateral earth pressure varied from the active earth pressure and the static earth pressure;the lateral earth pressure suggested by present code was not in accordance with the results by finite element method;and the degree of agreement between the reduction coefficients method for non-vertical excavation derived by different methods and the results by finite element method was not the same for different soil.
2011, 41(12): 98-101,115.
doi: 10.13204/j.gyjz201112022
Abstract:
There are many problems existing in the engineering application of concrete vertical-hole hollow block masonry, for instance poor thermal insulation, seepage and crack.To solve these problems, a new type concrete horizontal-hole hollow block masonry is developed.Nine groups with 54 compressive specimens and 4 groups with 16 shear specimens of the new type masonry were tested and the deformation characteristic and failure mechanism of the new type block masonry were obtained.Test results show that the formula of the current national standards is not suitable for the calculation for the new type block masonry and the average shear strength is increased dy 61%~110% as compared with the code.
There are many problems existing in the engineering application of concrete vertical-hole hollow block masonry, for instance poor thermal insulation, seepage and crack.To solve these problems, a new type concrete horizontal-hole hollow block masonry is developed.Nine groups with 54 compressive specimens and 4 groups with 16 shear specimens of the new type masonry were tested and the deformation characteristic and failure mechanism of the new type block masonry were obtained.Test results show that the formula of the current national standards is not suitable for the calculation for the new type block masonry and the average shear strength is increased dy 61%~110% as compared with the code.
2011, 41(12): 102-105.
doi: 10.13204/j.gyjz201112023
Abstract:
In order to research a method for detecting the strength of polyvinyl alcohol fiber cement mortar, based on the test method of concrete strength, the pull-out post-insert method is selected for experiment.The result demonstrates that there is a good linear relationship in the compressive strength of polyvinyl alcohol fiber cement mortar and pulling out post-insert force.By the regression analysis and the fitted line by the least square method, the fitted regression equation has a higher accuracy.
In order to research a method for detecting the strength of polyvinyl alcohol fiber cement mortar, based on the test method of concrete strength, the pull-out post-insert method is selected for experiment.The result demonstrates that there is a good linear relationship in the compressive strength of polyvinyl alcohol fiber cement mortar and pulling out post-insert force.By the regression analysis and the fitted line by the least square method, the fitted regression equation has a higher accuracy.
2011, 41(12): 106-110.
doi: 10.13204/j.gyjz201112024
Abstract:
The paper analyzes and systemizes the research work of some scholars on the issue of the strengthening effect of HPFL for RC structure.It concludes the basic characteristics and theory of HPFL strengthening RC structure, discusses the bonding HPFL to existing structure member and the advantages of HPFL strengthened RC structure.It systematically introduces the behavior of high-performance composite mortar in lamina reinforced materials of HPFL, the behavior of the reinforced constructional element in anti-bending, anti-shearing, compression resistance, seismic behavior, fatigue resistance and high temperature resistance etc, which provides some reference for the practical application of HPFL strengthened RC structure.
The paper analyzes and systemizes the research work of some scholars on the issue of the strengthening effect of HPFL for RC structure.It concludes the basic characteristics and theory of HPFL strengthening RC structure, discusses the bonding HPFL to existing structure member and the advantages of HPFL strengthened RC structure.It systematically introduces the behavior of high-performance composite mortar in lamina reinforced materials of HPFL, the behavior of the reinforced constructional element in anti-bending, anti-shearing, compression resistance, seismic behavior, fatigue resistance and high temperature resistance etc, which provides some reference for the practical application of HPFL strengthened RC structure.
2011, 41(12): 111-115.
doi: 10.13204/j.gyjz201112025
Abstract:
Through the bearing capacity test and finite element analysis of five nest light steel truss beams of different connection types, this paper made a study on the stress characteristics, failure mode and ultimate bearing capacity of nest light steel truss beam under vertical loads.The main factors which affect the flexural rigidity and ultimate bearing capacity of truss beam were also discussed.The result shows that the failure in truss beam mainly occurred at top chord near support or at mid-span due to the flexural or compression bending;the failure position will be changed by decreasing the distance between the first web member and support or using diagonal braces at the truss ends, but their effect on bearing capacity is not obvious;the ultimate bearing capacity of truss beam will be obviously increased after increasing cross section area of the top chord, but the change of bending stiffness of beams is little;the error of deflection simulation analysis is large with node rigid assumption, while results between simulation analysis and experimental values are more close with node semi-rigid assumption;the design of truss beam is mainly controlled by its mid-span deflection, the normal service bearing capacity of the truss beam can only reach 33~45 percent of ultimate bearing capacity.
Through the bearing capacity test and finite element analysis of five nest light steel truss beams of different connection types, this paper made a study on the stress characteristics, failure mode and ultimate bearing capacity of nest light steel truss beam under vertical loads.The main factors which affect the flexural rigidity and ultimate bearing capacity of truss beam were also discussed.The result shows that the failure in truss beam mainly occurred at top chord near support or at mid-span due to the flexural or compression bending;the failure position will be changed by decreasing the distance between the first web member and support or using diagonal braces at the truss ends, but their effect on bearing capacity is not obvious;the ultimate bearing capacity of truss beam will be obviously increased after increasing cross section area of the top chord, but the change of bending stiffness of beams is little;the error of deflection simulation analysis is large with node rigid assumption, while results between simulation analysis and experimental values are more close with node semi-rigid assumption;the design of truss beam is mainly controlled by its mid-span deflection, the normal service bearing capacity of the truss beam can only reach 33~45 percent of ultimate bearing capacity.
2011, 41(12): 116-120.
doi: 10.13204/j.gyjz201112026
Abstract:
Taking a group of steel plate shear wall(SPSW) with openings with or without edge members as example, this paper states the importance of edge members in view of initial stiffness, ultimate load and ductility.The reasonable stiffness value of edge member in SPSW with opening become the key to the problem, for inedquate stiffness makes anchorage of plate too weak to produce effective tension zone to consume energy while excessive stiffness will attract excessive seismic force, bringing adverse effect to structure.In order to get the reasonable stiffness range of edge members, stating with minimum inertia moments, this paper finds out from examples that initial stiffness changes geatly when the inertia moments ratio ranges from 6 to 8, which represents not only adequate anchorage from edge member stiffness, but also direct loading with main frame.Thus this range includes the optimal stiffness of edge members.To prove the rationality of the stiffness range deeply, analysis of expanding the aspect ratio of SPSW is carried out and results states that provided the stiffness of edge member locates in the reasonable range, the ultimate load increases apparently, while the ductility also increases slightly.
Taking a group of steel plate shear wall(SPSW) with openings with or without edge members as example, this paper states the importance of edge members in view of initial stiffness, ultimate load and ductility.The reasonable stiffness value of edge member in SPSW with opening become the key to the problem, for inedquate stiffness makes anchorage of plate too weak to produce effective tension zone to consume energy while excessive stiffness will attract excessive seismic force, bringing adverse effect to structure.In order to get the reasonable stiffness range of edge members, stating with minimum inertia moments, this paper finds out from examples that initial stiffness changes geatly when the inertia moments ratio ranges from 6 to 8, which represents not only adequate anchorage from edge member stiffness, but also direct loading with main frame.Thus this range includes the optimal stiffness of edge members.To prove the rationality of the stiffness range deeply, analysis of expanding the aspect ratio of SPSW is carried out and results states that provided the stiffness of edge member locates in the reasonable range, the ultimate load increases apparently, while the ductility also increases slightly.
2011, 41(12): 121-125.
doi: 10.13204/j.gyjz201112027
Abstract:
The construction of T-type CR joints with stiffening plate is proposed, according to principle of box column inner diaphragm.It is revealed that a reasonable construction measure will make the stiffened joints show plastic failure within diaphragm plate first, and then within square chords, the ultimate strength of the stiffened joints improve distinctively, and show good ductility, through the static test of T-type joints.The effects of the construction measures, failure mode and ultimate strength of T-type joints with single plate and double plates are discussed, based on nonlinear finite element method.The study found that the intersection line may sag uneven, or the circular brace may appear local buckling failure because of inner diaphragm.The construction measure of stiffened plate and the scope of the joints ultimate bearing capacity are proposed, and the improper plate's size is avoided.
The construction of T-type CR joints with stiffening plate is proposed, according to principle of box column inner diaphragm.It is revealed that a reasonable construction measure will make the stiffened joints show plastic failure within diaphragm plate first, and then within square chords, the ultimate strength of the stiffened joints improve distinctively, and show good ductility, through the static test of T-type joints.The effects of the construction measures, failure mode and ultimate strength of T-type joints with single plate and double plates are discussed, based on nonlinear finite element method.The study found that the intersection line may sag uneven, or the circular brace may appear local buckling failure because of inner diaphragm.The construction measure of stiffened plate and the scope of the joints ultimate bearing capacity are proposed, and the improper plate's size is avoided.
2011, 41(12): 126-129.
doi: 10.13204/j.gyjz201112028
Abstract:
Detection identification was undertaken for the existing railway bridges of Luanda and Benguela in Angola according to Verification Norms of Railway Bridge issued by Ministry of Railways of the People's Republic of China, the damages of the existing bridges caused by the war were recorded elaborately.The K289+560 bridge of Luanda railway was selected as the research object, static loading test in work site and structural bearing capacity calculation were undertaken, the restoration measures were also put forward for all the existing bridges according to the results and classification, which can be a good references for the renewal and detection to the similar existing railway bridge.
Detection identification was undertaken for the existing railway bridges of Luanda and Benguela in Angola according to Verification Norms of Railway Bridge issued by Ministry of Railways of the People's Republic of China, the damages of the existing bridges caused by the war were recorded elaborately.The K289+560 bridge of Luanda railway was selected as the research object, static loading test in work site and structural bearing capacity calculation were undertaken, the restoration measures were also put forward for all the existing bridges according to the results and classification, which can be a good references for the renewal and detection to the similar existing railway bridge.
2011, 41(12): 130-136.
doi: 10.13204/j.gyjz201112029
Abstract:
Built in 1921, Tsinghua University West Gymnasium is a country-level key historical relic building.The paper introduces the historical background and the stadium situation, focusing on the preparation before the repair work and the repair measures for reinforcement.By underpinning the whole basis, additional structural columns and ring beam, wall reinforcement, additional boom of roof, repair exterior wall, roof repair, parts repair of local damage, decoration, treatment of surrounding environment, those protection technologies ensure the structural safety of the West Gymnasium and adding new functions to it.Its successful experience can be used for reinforcement of similar modern heritage buildings, and provides reference information.
Built in 1921, Tsinghua University West Gymnasium is a country-level key historical relic building.The paper introduces the historical background and the stadium situation, focusing on the preparation before the repair work and the repair measures for reinforcement.By underpinning the whole basis, additional structural columns and ring beam, wall reinforcement, additional boom of roof, repair exterior wall, roof repair, parts repair of local damage, decoration, treatment of surrounding environment, those protection technologies ensure the structural safety of the West Gymnasium and adding new functions to it.Its successful experience can be used for reinforcement of similar modern heritage buildings, and provides reference information.
2011, 41(12): 137-140.
doi: 10.13204/j.gyjz201112030
Abstract:
Large deformation on the tunnel top and adjacent slope occurred during the face excavation construction of left line of Yuanyanghui tunnel on Shanping express highway, with maximal displacement of 34 cm monitored on site.Based on the analysis of tunnel construction process, site monitoring was carried out to the tunnel and adjacent slope, relevant theory and method were applied to investigate the inducement of its unfavorable deformation caused by excavation of tunnel opening, and control measures were also proposed according to monitoring analysis results.The face excavation construction under the control measures was analyzed by numeral simulation, it turned out to be reasonable.
Large deformation on the tunnel top and adjacent slope occurred during the face excavation construction of left line of Yuanyanghui tunnel on Shanping express highway, with maximal displacement of 34 cm monitored on site.Based on the analysis of tunnel construction process, site monitoring was carried out to the tunnel and adjacent slope, relevant theory and method were applied to investigate the inducement of its unfavorable deformation caused by excavation of tunnel opening, and control measures were also proposed according to monitoring analysis results.The face excavation construction under the control measures was analyzed by numeral simulation, it turned out to be reasonable.
2011, 41(12): 141-145,105.
doi: 10.13204/j.gyjz201112031
Abstract:
Due to the change of structural function, one teaching building had to be retrofitted to a large-space office building.The underpinning technology had been adopted to transform this brick-concrete structure to a frame structure.In order to ensure its safety operation, fiber bragg grating technology(FBG) and distributed optical fiber sensor(BOTDA) had been used to monitor structural stress and strain during the whole period of construction.The test results show that the designed underpinning system performances well and can provide sufficient bearing capacity for this new retrofitted structure.
Due to the change of structural function, one teaching building had to be retrofitted to a large-space office building.The underpinning technology had been adopted to transform this brick-concrete structure to a frame structure.In order to ensure its safety operation, fiber bragg grating technology(FBG) and distributed optical fiber sensor(BOTDA) had been used to monitor structural stress and strain during the whole period of construction.The test results show that the designed underpinning system performances well and can provide sufficient bearing capacity for this new retrofitted structure.
2011, 41(12): 146-149.
doi: 10.13204/j.gyjz201112032
Abstract:
The article is about the process of planning of new campus of Qingdao Technological University, Starting from the spatial form, traffic organization, building image and cultural heritage etc, as well as through rational analysis and design, it has been explored that the ideas and methods of designing a mountain campus by integrating romanticism into the rational order, landscape poetry into the environmental mood, and geographical cultural characteristics into the image of buidings, and combining with spatial enviroments of mountains and rivers.
The article is about the process of planning of new campus of Qingdao Technological University, Starting from the spatial form, traffic organization, building image and cultural heritage etc, as well as through rational analysis and design, it has been explored that the ideas and methods of designing a mountain campus by integrating romanticism into the rational order, landscape poetry into the environmental mood, and geographical cultural characteristics into the image of buidings, and combining with spatial enviroments of mountains and rivers.
2011, 41(12): 150-153.
doi: 10.13204/j.gyjz201112033
Abstract:
The paper introduces the development and concept of green building.The importance and necessities of green building concepts are stressed.By using green building eco-system, the paper illustrates the ecological design of a metallurgical plant, including structure shaping, space enclosing structure, ventilation, light, windows, doors and greening, which are all based on eco-system strategies.Energy-saving and environment protection are the goals to realize.
The paper introduces the development and concept of green building.The importance and necessities of green building concepts are stressed.By using green building eco-system, the paper illustrates the ecological design of a metallurgical plant, including structure shaping, space enclosing structure, ventilation, light, windows, doors and greening, which are all based on eco-system strategies.Energy-saving and environment protection are the goals to realize.
