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2012 Vol. 42, No. 2
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2012, 42(2): 1-4.
doi: 10.13204/j.gyjz201202001
Abstract:
Reasonable design of a building in the conceptual phase can fully exploit the potential of natural ventilation and make maximal use of local climatic resources.It is meaningful for design of low-carbon architecture.With one office building to be built as an example,the influence of the external openings and internal partitions on the indoor natural ventilation effect was numerically simulated.It was found that the mean wind velocity and impact factor of nature wind were larger by adopted the optimized scheme.The age of air indoor was mostly less than 5 min.And the effect of natural ventilation was well,which provided reference and technical basis for the natural ventilation design of the building.
Reasonable design of a building in the conceptual phase can fully exploit the potential of natural ventilation and make maximal use of local climatic resources.It is meaningful for design of low-carbon architecture.With one office building to be built as an example,the influence of the external openings and internal partitions on the indoor natural ventilation effect was numerically simulated.It was found that the mean wind velocity and impact factor of nature wind were larger by adopted the optimized scheme.The age of air indoor was mostly less than 5 min.And the effect of natural ventilation was well,which provided reference and technical basis for the natural ventilation design of the building.
2012, 42(2): 5-9,26.
doi: 10.13204/j.gyjz201202002
Abstract:
In the initial stage of the integrated design of solar hot water system for high-rise residential buildings,the architects need to consider the effective combination of the collector and the architecture,which can make full use of solar energy,but also meet the needs of archi tectural esthetics.It is put forward a design concept of mansard double-pitch asymmetrical solar roof,which may provide some reference for designers.
In the initial stage of the integrated design of solar hot water system for high-rise residential buildings,the architects need to consider the effective combination of the collector and the architecture,which can make full use of solar energy,but also meet the needs of archi tectural esthetics.It is put forward a design concept of mansard double-pitch asymmetrical solar roof,which may provide some reference for designers.
2012, 42(2): 10-13,69.
doi: 10.13204/j.gyjz201202003
Abstract:
The energy-conservation reform of buildings can effectively reduce high energy consumption and high pollution problems in existing buildings.Ecological energy-saving technology in building reconstruction has been researched preliminarily,type mode and methods have been analyzed and combined with specific examples,energy-saving measures in the specific applications have been discussed in the process of transformation,in order to find out he sustainable development of ecological road in the energy-conservation reform of existing buildings.
The energy-conservation reform of buildings can effectively reduce high energy consumption and high pollution problems in existing buildings.Ecological energy-saving technology in building reconstruction has been researched preliminarily,type mode and methods have been analyzed and combined with specific examples,energy-saving measures in the specific applications have been discussed in the process of transformation,in order to find out he sustainable development of ecological road in the energy-conservation reform of existing buildings.
2012, 42(2): 14-18,73.
doi: 10.13204/j.gyjz201202004
Abstract:
By analyzing the Fujian's current status of energy and building energy-saving design in southeast Fujian,with the combination of the characteristics of local climates and resources,the principles and methods of buliding ecological energy-saving design in southeast Fujian were explored,and the corresponding strategy and technology system for this region were also presented.
By analyzing the Fujian's current status of energy and building energy-saving design in southeast Fujian,with the combination of the characteristics of local climates and resources,the principles and methods of buliding ecological energy-saving design in southeast Fujian were explored,and the corresponding strategy and technology system for this region were also presented.
2012, 42(2): 19-22,36.
doi: 10.13204/j.gyjz201202005
Abstract:
Yinchuan is located in the desert area in northwest China,ecological environment is worse.Jianfuqiao village in Yinchuan suburbs was chosen as object for new rural construction.The passive solar folk house was designed based on local abundant solar energy resource.Passive solar houses,straw-bale,rice husk board,sloping roofs and other eco-construction techniques were used for the new house.After building,the measuring devices were used to monitor and record temperature,relative humidity,solar radiation etc.in winter.The main factors of indoor thermal environment were pointed out.Analysis of the summer indoor ventilation simulation was carried out.The results of testing and simulation show that the new folk house is warm in winter and cool in summer,which provides a useful reference for new rural construction in northwest China.
Yinchuan is located in the desert area in northwest China,ecological environment is worse.Jianfuqiao village in Yinchuan suburbs was chosen as object for new rural construction.The passive solar folk house was designed based on local abundant solar energy resource.Passive solar houses,straw-bale,rice husk board,sloping roofs and other eco-construction techniques were used for the new house.After building,the measuring devices were used to monitor and record temperature,relative humidity,solar radiation etc.in winter.The main factors of indoor thermal environment were pointed out.Analysis of the summer indoor ventilation simulation was carried out.The results of testing and simulation show that the new folk house is warm in winter and cool in summer,which provides a useful reference for new rural construction in northwest China.
2012, 42(2): 23-26,9.
doi: 10.13204/j.gyjz201202006
Abstract:
This research about the ecosystem of large space building mainly contains site planning,architectural form design,building materials selection,landscape greening and energy saving of construction equipment.It is presented principle and design strategy of large space public building ecological design,also pointed out each link of energy saving design of large space public building in the life cycle,hoping to provide some references and useful guidance for the colleagues of architectural design.
This research about the ecosystem of large space building mainly contains site planning,architectural form design,building materials selection,landscape greening and energy saving of construction equipment.It is presented principle and design strategy of large space public building ecological design,also pointed out each link of energy saving design of large space public building in the life cycle,hoping to provide some references and useful guidance for the colleagues of architectural design.
2012, 42(2): 27-32,77.
doi: 10.13204/j.gyjz201202007
Abstract:
Along with the economic progress and the living standard enhancement,the building scope and energy consumption of Lhasa had a large-scale expansion.Through two field investigations in winter,the basic survey items,such as indoor air temperature,the evaluation of the thermal environment and so on were analyzed.The result shows that the direct gain system and the attached solar space system are used spontaneously for the existing residential buildings.However,the indoor thermal environment still needs to be improved.Considered that Lhasa city was classified into heating area,the city faces the problem of huge increasing of the heating energy consumption.The basic model of direct solar gain system was established based on the common residential buildings,and the basic elements of passive design were analyzed by the simulation.The last result gives reasonable suggestion on the local residential building design.
Along with the economic progress and the living standard enhancement,the building scope and energy consumption of Lhasa had a large-scale expansion.Through two field investigations in winter,the basic survey items,such as indoor air temperature,the evaluation of the thermal environment and so on were analyzed.The result shows that the direct gain system and the attached solar space system are used spontaneously for the existing residential buildings.However,the indoor thermal environment still needs to be improved.Considered that Lhasa city was classified into heating area,the city faces the problem of huge increasing of the heating energy consumption.The basic model of direct solar gain system was established based on the common residential buildings,and the basic elements of passive design were analyzed by the simulation.The last result gives reasonable suggestion on the local residential building design.
2012, 42(2): 33-36,22.
doi: 10.13204/j.gyjz201202008
Abstract:
The analysis of the generation and development of foreign straw-bale buildings,reveals the features,such as natural renewal,zero emission,and low power consumption and high thermal insulation of straw materials,which con meet the requirements of environmental sustainable development and the psychological needs of people living close to nature.It is the intrinsic motivation of the occurrence and development of foreign straw-bale buildings.The technological is the guarantee development of structure,water-resistance,fire-resistance and construction to construct straw-bale buildings and form a more mature technological norm system.Straw-bale building is worth noticing closely.
The analysis of the generation and development of foreign straw-bale buildings,reveals the features,such as natural renewal,zero emission,and low power consumption and high thermal insulation of straw materials,which con meet the requirements of environmental sustainable development and the psychological needs of people living close to nature.It is the intrinsic motivation of the occurrence and development of foreign straw-bale buildings.The technological is the guarantee development of structure,water-resistance,fire-resistance and construction to construct straw-bale buildings and form a more mature technological norm system.Straw-bale building is worth noticing closely.
2012, 42(2): 37-40.
doi: 10.13204/j.gyjz201202009
Abstract:
Recently,the planning and construction of ecological residential district occurs prevalently in China.However,since such district is still in its primary stage domestically,there is no clear definition and no unified system of evaluation,which can give rise to some misunderstandings.It is descibed three main kinds of misunderstandings and,combined with the examples in China and abroad,it is also analyzed the strategy of ecological residential district constructions.
Recently,the planning and construction of ecological residential district occurs prevalently in China.However,since such district is still in its primary stage domestically,there is no clear definition and no unified system of evaluation,which can give rise to some misunderstandings.It is descibed three main kinds of misunderstandings and,combined with the examples in China and abroad,it is also analyzed the strategy of ecological residential district constructions.
2012, 42(2): 41-47.
doi: 10.13204/j.gyjz201202010
Abstract:
The frame structure of pre-heater is one important industrial building in the NSP cement production lines.It was investigated that the nonlinear responses of one certain pre-heater frame structure under variable earthquake intensity motions with elasto-plastic time-history analysis and also studied the inherent law.The analysis revealed the yield mechanism and the failure mode of the structure.It was also discussed the importance of brace member for the structure,and obtained some valuable conclusions for the aseismic design of pre-heater frame structure.
The frame structure of pre-heater is one important industrial building in the NSP cement production lines.It was investigated that the nonlinear responses of one certain pre-heater frame structure under variable earthquake intensity motions with elasto-plastic time-history analysis and also studied the inherent law.The analysis revealed the yield mechanism and the failure mode of the structure.It was also discussed the importance of brace member for the structure,and obtained some valuable conclusions for the aseismic design of pre-heater frame structure.
2012, 42(2): 48-53.
doi: 10.13204/j.gyjz201202011
Abstract:
Based on the verification of the accuracy of numerical simulation and grid size,it was simulated the internal explosion of an cuboid using Euler-FCT method and two-step simulation,taking account of multiple reflections.It was studied the cavity effect of doors and windows,the effect of the windowsill high and window size on blast wave propagation,and also analysed the result.Cavity effect has a great impact on blast wave propagation which can not be ignored.Window size has a certain influence on blast wave propagation,and the effect of windowsill height is relatively small.
Based on the verification of the accuracy of numerical simulation and grid size,it was simulated the internal explosion of an cuboid using Euler-FCT method and two-step simulation,taking account of multiple reflections.It was studied the cavity effect of doors and windows,the effect of the windowsill high and window size on blast wave propagation,and also analysed the result.Cavity effect has a great impact on blast wave propagation which can not be ignored.Window size has a certain influence on blast wave propagation,and the effect of windowsill height is relatively small.
2012, 42(2): 54-57.
doi: 10.13204/j.gyjz201202012
Abstract:
FEM was employed to study frame-supported multi-ribbed wall beam under vertical load.Using the changes in performance parameters such as divided form of wall,the size of the side column and the ratio of in-filled block and multi-ribbed frame,the mechanism of frame-supported multi-ribbed wall beam and the influencing factors of the parameters of wall to the wall beam are studied.Which provides references for the optimization and engineering practice of frame-supported multi-ribbed wall.
FEM was employed to study frame-supported multi-ribbed wall beam under vertical load.Using the changes in performance parameters such as divided form of wall,the size of the side column and the ratio of in-filled block and multi-ribbed frame,the mechanism of frame-supported multi-ribbed wall beam and the influencing factors of the parameters of wall to the wall beam are studied.Which provides references for the optimization and engineering practice of frame-supported multi-ribbed wall.
2012, 42(2): 58-61.
doi: 10.13204/j.gyjz201202013
Abstract:
Prestressed slab-column structure must be affected by lateral restraint when prestressed tendons were being tensioned.The law of this influence was analysed by a test of an actual project.According to compatibility of deformation,an equation set to solve lateral restraint effects for one-storey and multiple-span frame was built up.Based on the basic assumptions,a simplified formula to calculate the secondary shearing force of column was obtained,with which the law of the lateral restraint effects for the project was analysed.The equation set built up at this paper could solve lateral restraint effects of horizontal members more accurately.
Prestressed slab-column structure must be affected by lateral restraint when prestressed tendons were being tensioned.The law of this influence was analysed by a test of an actual project.According to compatibility of deformation,an equation set to solve lateral restraint effects for one-storey and multiple-span frame was built up.Based on the basic assumptions,a simplified formula to calculate the secondary shearing force of column was obtained,with which the law of the lateral restraint effects for the project was analysed.The equation set built up at this paper could solve lateral restraint effects of horizontal members more accurately.
2012, 42(2): 62-65.
doi: 10.13204/j.gyjz201202014
Abstract:
Based on field testing of horizontal-axis wind turbine tower under two different working conditions in Wuchuan Area of Inner Mongolia,a further analysis was made by DASP system and the acceleration spectrum and characteristic frequency were obtained,then a finite element model of the tower was set up and a modal analysis was done by applying ANSYS software,taking account of the effect of engine room mass on the top of the tower.The measured results and calculated results provided a basis for avoiding resonance and further studying of structure dynamic response of wind tower,in addition,the modal data had a valuable reference for wind tower design and structural vibration control.
Based on field testing of horizontal-axis wind turbine tower under two different working conditions in Wuchuan Area of Inner Mongolia,a further analysis was made by DASP system and the acceleration spectrum and characteristic frequency were obtained,then a finite element model of the tower was set up and a modal analysis was done by applying ANSYS software,taking account of the effect of engine room mass on the top of the tower.The measured results and calculated results provided a basis for avoiding resonance and further studying of structure dynamic response of wind tower,in addition,the modal data had a valuable reference for wind tower design and structural vibration control.
2012, 42(2): 66-69,13.
doi: 10.13204/j.gyjz201202015
Abstract:
Through the cyclic test of reinforced concrete column under different axial compression ratio,the effect of corrosion degree on hysteretic behavior,capacity and ductility is analysed.The test shows that as corrosion degree increases,the fullness of hysteretic curve of specimen is decreased gradually,yield load,limit load and ductility are lowered to different extent.
Through the cyclic test of reinforced concrete column under different axial compression ratio,the effect of corrosion degree on hysteretic behavior,capacity and ductility is analysed.The test shows that as corrosion degree increases,the fullness of hysteretic curve of specimen is decreased gradually,yield load,limit load and ductility are lowered to different extent.
2012, 42(2): 70-73,18.
doi: 10.13204/j.gyjz201202016
Abstract:
To study the influence of steel strands corrosion on the long-term behavior of bond-creep,6 pre-tensioned prestressed concrete beams were fabricated,of which,5 beams were mixed with salt and set in different places to be corroded in different intensity for 47 weeks,and the bond-slip of all the 6 beams was tested periodically through the whole period,and then the time varying curves of bond-slip under prestressing were obtained.The results show that under the condition of no corrosion crack,the bond strength increases with corrosion and the bond-creep is restrained,which contribute the creep slip of corrosion beams being less than that of the uncorrosion beam.Moreover,with the increase of corrosion rate and corrosion products expansion ratio,the long-term bond-slip decreases.The analysis shows that if there are corrosion cracks and the bond strength deteriorates,the long-term bond-creep and the load cracks width in anchoring segments should increase,but the prestressing loss and the anchoring bearing capacity should not decrease.
To study the influence of steel strands corrosion on the long-term behavior of bond-creep,6 pre-tensioned prestressed concrete beams were fabricated,of which,5 beams were mixed with salt and set in different places to be corroded in different intensity for 47 weeks,and the bond-slip of all the 6 beams was tested periodically through the whole period,and then the time varying curves of bond-slip under prestressing were obtained.The results show that under the condition of no corrosion crack,the bond strength increases with corrosion and the bond-creep is restrained,which contribute the creep slip of corrosion beams being less than that of the uncorrosion beam.Moreover,with the increase of corrosion rate and corrosion products expansion ratio,the long-term bond-slip decreases.The analysis shows that if there are corrosion cracks and the bond strength deteriorates,the long-term bond-creep and the load cracks width in anchoring segments should increase,but the prestressing loss and the anchoring bearing capacity should not decrease.
2012, 42(2): 74-77,32.
doi: 10.13204/j.gyjz201202017
Abstract:
Experimental research on five large-scaled six-pile caps showed that pile caps under concrete wall conform to spatial truss model with concrete struts and rebar ties.The failure might be caused by splitting of concrete struts or yielding of rebar.Elasto-plastic analysis was carried out with ABQUS program,and the results were highly in accordance with the test results.
Experimental research on five large-scaled six-pile caps showed that pile caps under concrete wall conform to spatial truss model with concrete struts and rebar ties.The failure might be caused by splitting of concrete struts or yielding of rebar.Elasto-plastic analysis was carried out with ABQUS program,and the results were highly in accordance with the test results.
2012, 42(2): 78-81,86.
doi: 10.13204/j.gyjz201202018
Abstract:
The Element-Free Galerkin Method(EFGM) is a typical kind of meshless method,it has innovation theory and complete structure.Constructing interpolation function by using the moving least-squares technique,it was obtained a approximate scheme of field function.Based on the Mindlin plate theory,the governing equations of EFGM to deflection solution of circular mindlin plate bending on Winkler elastic soil foundation were established.Numerical results indicated that the above method and the corresponding program were effective and accurate.The work of this paper provided a new effective method for the bending of circular plate in practice.
The Element-Free Galerkin Method(EFGM) is a typical kind of meshless method,it has innovation theory and complete structure.Constructing interpolation function by using the moving least-squares technique,it was obtained a approximate scheme of field function.Based on the Mindlin plate theory,the governing equations of EFGM to deflection solution of circular mindlin plate bending on Winkler elastic soil foundation were established.Numerical results indicated that the above method and the corresponding program were effective and accurate.The work of this paper provided a new effective method for the bending of circular plate in practice.
2012, 42(2): 82-86,81.
doi: 10.13204/j.gyjz201202019
Abstract:
In view of the adequate embedded depth is very important to cantilever bracing structure for excavation,and the stability problem of excavation is a fuzzy-random event which includes random and fuzzy failure characteristics,the optimization analysis for embedded depth was studied based on the fuzzy probability theory.The example's results indicated that the fuzzy failure probability would decrease with the increasing of the embedded depth,and therefore,the embedded depth of cantilever bracing structure for excavation could be determined rationally,which satisfied the safety and economical requests.
In view of the adequate embedded depth is very important to cantilever bracing structure for excavation,and the stability problem of excavation is a fuzzy-random event which includes random and fuzzy failure characteristics,the optimization analysis for embedded depth was studied based on the fuzzy probability theory.The example's results indicated that the fuzzy failure probability would decrease with the increasing of the embedded depth,and therefore,the embedded depth of cantilever bracing structure for excavation could be determined rationally,which satisfied the safety and economical requests.
2012, 42(2): 87-91,143.
doi: 10.13204/j.gyjz201202020
Abstract:
In the project of passenger dedicated Line from Beijing to Shijiazhuang,a 5 km long tunnel parallel to the existing Beijing to Guangzhou Railway Line with a distance ranging from 5 m to 20 m was built with open excavation method.The longtime and continuous dynamic load caused by running trains would necessarily influence stability of tunnel supporting structure.So it was vital to establish the reasonable locking force value of anchor based on study on response law of anchor force.Thereby a site test was designed on a standard tunnel section and performed to measure anchor force for half a year.Meanwhile a digital model was made with FLAC-3D according to site condition and construction steps to analyse the law.The research showed there existed a critical value of locking force.Bigger than that,the supporting structure would be stable and the fluctuation of anchor force would not cause obvious stable problem.Smaller than that,the supporting structure was sensitive to dynamic load.Under the condition,the displacement of anchor head satisfied parabola function with locking force.The relative variation range of dynamic stress rised in line with power function with increase of vibration strength and decrease of distance of train.The test data partly proved the foregoing conclusions.
In the project of passenger dedicated Line from Beijing to Shijiazhuang,a 5 km long tunnel parallel to the existing Beijing to Guangzhou Railway Line with a distance ranging from 5 m to 20 m was built with open excavation method.The longtime and continuous dynamic load caused by running trains would necessarily influence stability of tunnel supporting structure.So it was vital to establish the reasonable locking force value of anchor based on study on response law of anchor force.Thereby a site test was designed on a standard tunnel section and performed to measure anchor force for half a year.Meanwhile a digital model was made with FLAC-3D according to site condition and construction steps to analyse the law.The research showed there existed a critical value of locking force.Bigger than that,the supporting structure would be stable and the fluctuation of anchor force would not cause obvious stable problem.Smaller than that,the supporting structure was sensitive to dynamic load.Under the condition,the displacement of anchor head satisfied parabola function with locking force.The relative variation range of dynamic stress rised in line with power function with increase of vibration strength and decrease of distance of train.The test data partly proved the foregoing conclusions.
2012, 42(2): 92-96,146.
doi: 10.13204/j.gyjz201202021
Abstract:
The application of vibroflotation without additional backfill treatment in silty fine sands is not so common．Combined with one key project in Shanghai，the engineering properties of saturated loose silty fine sands wereinvestigated through in-situ vibroflotation test． The effect of initial underground water level，dissipation regularity ofpore water pressure， effects of cone penetration test ( CPT) and standard penetration test ( SPT) were explored．Research shows that the treatment effect is not so good if the underground water level is too low，and the pore waterpressure generated during vibroflotation is related closely with the vibroflotation points and frequency，and foundationcapability is greatly improved after treatment． Summarizing the rest results，some rational construction techniques and parameters were suggested． Research testified the applicability of vibroflotation without additional backfill treatment in saturated silty fine sands．
The application of vibroflotation without additional backfill treatment in silty fine sands is not so common．Combined with one key project in Shanghai，the engineering properties of saturated loose silty fine sands wereinvestigated through in-situ vibroflotation test． The effect of initial underground water level，dissipation regularity ofpore water pressure， effects of cone penetration test ( CPT) and standard penetration test ( SPT) were explored．Research shows that the treatment effect is not so good if the underground water level is too low，and the pore waterpressure generated during vibroflotation is related closely with the vibroflotation points and frequency，and foundationcapability is greatly improved after treatment． Summarizing the rest results，some rational construction techniques and parameters were suggested． Research testified the applicability of vibroflotation without additional backfill treatment in saturated silty fine sands．
2012, 42(2): 97-100,106.
doi: 10.13204/j.gyjz201202022
Abstract:
No-sand concrete micro-pile post-treatment technology has the obvious effect on processing weak subgrade and expressway broadening.Through field research it was introduced effects of the treatment.Finite element numerical models were established to analyze the stress of powder-jetted piles and no-sand concrete micro-piles,excess pore pressure change and deformation characteristics of the typical embankment section,so as to verify effectiveness of its use.Through the parameters analysis,the using condition of the soil coefficient of permeability was obtained.By analyzing powder-jetted piles and no-sand concrete micro-piles in the condition of different pile length,regularities of exceed pore pressure,road embankment settlement and the stress ratio of pile-soil were obtained.Which provided a theoretic guide for further use of no-sand concrete micro-pile post-treatment technology.
No-sand concrete micro-pile post-treatment technology has the obvious effect on processing weak subgrade and expressway broadening.Through field research it was introduced effects of the treatment.Finite element numerical models were established to analyze the stress of powder-jetted piles and no-sand concrete micro-piles,excess pore pressure change and deformation characteristics of the typical embankment section,so as to verify effectiveness of its use.Through the parameters analysis,the using condition of the soil coefficient of permeability was obtained.By analyzing powder-jetted piles and no-sand concrete micro-piles in the condition of different pile length,regularities of exceed pore pressure,road embankment settlement and the stress ratio of pile-soil were obtained.Which provided a theoretic guide for further use of no-sand concrete micro-pile post-treatment technology.
2012, 42(2): 101-106,100.
doi: 10.13204/j.gyjz201202023
Abstract:
Five mixing processes of producing recycled concrete were considered,including cement paste soaking recycled coarse aggregate process,whose water-cement ratio is 0.50,025,and cement paste dosage is only half.The other two processes are traditional process and two-stage mixing process.The performance of recycled concrete produced by them was measured.It was found that the first mixing process could indistinctively improve 28 d compressive strength of recycled concrete,instead of the strength of 56 d reduced,the splitting tensile strength of the two ages were both relatively low,moreover,the discreteness of compressive strength was big;the compressive and tensile strengths of recycled concrete produced by the second mixing process were the lowest,moreover,the discreteness of strength was big;the both of strength produced by the third mixing process was higher than that of the former two,but the discreteness of strength was less than that of the former two,but bigger than that of the latter two.The two-stage mixing process could not only improve the compressive strength and splitting tensile strength of recycled concrete but also improve its working performance.Meanwhile,the discreteness of the strength of concrete made by this way is small.The recycled concrete produced by the traditional process also shows high compressive strength,high tensile strength and low discreteness of strength and this process is quite simple.
Five mixing processes of producing recycled concrete were considered,including cement paste soaking recycled coarse aggregate process,whose water-cement ratio is 0.50,025,and cement paste dosage is only half.The other two processes are traditional process and two-stage mixing process.The performance of recycled concrete produced by them was measured.It was found that the first mixing process could indistinctively improve 28 d compressive strength of recycled concrete,instead of the strength of 56 d reduced,the splitting tensile strength of the two ages were both relatively low,moreover,the discreteness of compressive strength was big;the compressive and tensile strengths of recycled concrete produced by the second mixing process were the lowest,moreover,the discreteness of strength was big;the both of strength produced by the third mixing process was higher than that of the former two,but the discreteness of strength was less than that of the former two,but bigger than that of the latter two.The two-stage mixing process could not only improve the compressive strength and splitting tensile strength of recycled concrete but also improve its working performance.Meanwhile,the discreteness of the strength of concrete made by this way is small.The recycled concrete produced by the traditional process also shows high compressive strength,high tensile strength and low discreteness of strength and this process is quite simple.
2012, 42(2): 107-110.
doi: 10.13204/j.gyjz201202024
Abstract:
The practice of one-step molding method of vase-shaped columnar pier for urban viaduct bridges,includes the design of mortar mix,fabrication of mortar formwork and installation of reinforcement for column top during pouring concrete piers.Based on the fast-track of Wuhan Huangpu Street Jinqiao Road,it was introduced the main construction process and key points of operation of one-step molding method of vase-shaped columnar pier in detail.And the construction technology described above has gained high quality economic benefit and profits in practice of the project.
The practice of one-step molding method of vase-shaped columnar pier for urban viaduct bridges,includes the design of mortar mix,fabrication of mortar formwork and installation of reinforcement for column top during pouring concrete piers.Based on the fast-track of Wuhan Huangpu Street Jinqiao Road,it was introduced the main construction process and key points of operation of one-step molding method of vase-shaped columnar pier in detail.And the construction technology described above has gained high quality economic benefit and profits in practice of the project.
2012, 42(2): 111-114.
doi: 10.13204/j.gyjz201202025
Abstract:
Combined with the monitoring example of the open-cut section of a cable tunnel for Houde Substation in Guangzhou,the monitoring safety design and instrument layout were introduced in the system of steel sheet pile and steel struts structure.The monitoring frequency,alertness values and reports etc were presented.According to the analysis and forecast of monitoring data especially the unusual ones,monitoring result was researched to adopt countermeasures,and safety precautions were adopted in time,hence the safety of the field and environment could be ensured.
Combined with the monitoring example of the open-cut section of a cable tunnel for Houde Substation in Guangzhou,the monitoring safety design and instrument layout were introduced in the system of steel sheet pile and steel struts structure.The monitoring frequency,alertness values and reports etc were presented.According to the analysis and forecast of monitoring data especially the unusual ones,monitoring result was researched to adopt countermeasures,and safety precautions were adopted in time,hence the safety of the field and environment could be ensured.
2012, 42(2): 115-119.
doi: 10.13204/j.gyjz201202026
Abstract:
It was studied the punching failure mechanism,position of blunted cut,and the influence of punching bearing capacity factors of node of the column footing in beam form of CFST column with studs embedding in the reinforced concrete foundation under static loading through quasi-static method.The research showed that punching area of the concrete extended because the upper edge of punching area moved from the bottom of steel tube to the highest studs,which improved the bearing capacity of resisting punching of the component after welding studs outside the steel tube.When the number of the studs is enough and their layout is reasonable,the bearing capacity of resisting punching of the column footing can be greater than the capacity of resisting shear.The safety of the components can be ensured if the column footing node meets the flexural and shear requirement.
It was studied the punching failure mechanism,position of blunted cut,and the influence of punching bearing capacity factors of node of the column footing in beam form of CFST column with studs embedding in the reinforced concrete foundation under static loading through quasi-static method.The research showed that punching area of the concrete extended because the upper edge of punching area moved from the bottom of steel tube to the highest studs,which improved the bearing capacity of resisting punching of the component after welding studs outside the steel tube.When the number of the studs is enough and their layout is reasonable,the bearing capacity of resisting punching of the column footing can be greater than the capacity of resisting shear.The safety of the components can be ensured if the column footing node meets the flexural and shear requirement.
2012, 42(2): 120-124.
doi: 10.13204/j.gyjz201202027
Abstract:
In order to investigate the stability behavior of channels with complex edge stiffeners under axial load between fixed-ends,a total of 292 members with different parameters such as width-to-thickness ratio of flanges,section shapes,length of column,stiffener length were selected to be studied by nonlinear finite element analysis.The influence of the above parameters on stability behavior of channels with complex edge stiffeners were studied.It is shown that fixed-ended columns are more prone to distortional buckling.When width-to-thickness ratio of flanges is big,the overall instability mode tends to perform the flexural-torsional buckling.The ultimate load-carrying capacity of members decreases with the increase in the flange width-to-thickness ratio and slenderness ratio.With differences of width-to-thickness ratio of flanges,two different rules were shown about the influence of edge stiffeners on the load-carrying efficiency of members.
In order to investigate the stability behavior of channels with complex edge stiffeners under axial load between fixed-ends,a total of 292 members with different parameters such as width-to-thickness ratio of flanges,section shapes,length of column,stiffener length were selected to be studied by nonlinear finite element analysis.The influence of the above parameters on stability behavior of channels with complex edge stiffeners were studied.It is shown that fixed-ended columns are more prone to distortional buckling.When width-to-thickness ratio of flanges is big,the overall instability mode tends to perform the flexural-torsional buckling.The ultimate load-carrying capacity of members decreases with the increase in the flange width-to-thickness ratio and slenderness ratio.With differences of width-to-thickness ratio of flanges,two different rules were shown about the influence of edge stiffeners on the load-carrying efficiency of members.
2012, 42(2): 125-128,138.
doi: 10.13204/j.gyjz201202028
Abstract:
In Code for Design of Steel Structure(GB 500172003),only the influence of axial force can be considered as the calculation of bearing capacity of tubular multi-planar joint,and that of web member's bending moment on the bearing capacity can not be considered.In Hollow Tube Structure Connecting,the formula is mainly refers to Eurocode 3,which is used to calculate capacity of single-planar tubular joint under combined forces.Therefore,it can be used as reference for design.Compared with the formula of GB 500172003,calculating the bearing capacity of tubular joint by the formula in Eurocode 3 is safe.According to Eurocode 3,the tubular joint is divided into several single-planar joints,and then checking calculation is proceeded for everyone.Using ANSYS software to make a solid finite element model for the tubular joint and the nonlinearity is analyzed.Simulation results indicate that the design of tubular joint meets the requirements.
In Code for Design of Steel Structure(GB 500172003),only the influence of axial force can be considered as the calculation of bearing capacity of tubular multi-planar joint,and that of web member's bending moment on the bearing capacity can not be considered.In Hollow Tube Structure Connecting,the formula is mainly refers to Eurocode 3,which is used to calculate capacity of single-planar tubular joint under combined forces.Therefore,it can be used as reference for design.Compared with the formula of GB 500172003,calculating the bearing capacity of tubular joint by the formula in Eurocode 3 is safe.According to Eurocode 3,the tubular joint is divided into several single-planar joints,and then checking calculation is proceeded for everyone.Using ANSYS software to make a solid finite element model for the tubular joint and the nonlinearity is analyzed.Simulation results indicate that the design of tubular joint meets the requirements.
2012, 42(2): 129-133,151.
doi: 10.13204/j.gyjz201202029
Abstract:
It is presented a brief review on FRP for the seismic retrofit of RC columns,including the theories of FRP-strengthened RC columns,failure modes,the conclusions obtained through experimental investigations,finite element simulations,seismic performance evaluation and further developments of FRP reinforced columns.Displacement ductility coefficient and curvature ductility coefficient are two quantificational indices for seismic ductility design.It is also introduced three useful methods to calculate displacement ductility coefficient,and curvature enhancement coefficient is used to measure curvature ductility coefficient,it is expected to provide useful conclusions for further investigations.
It is presented a brief review on FRP for the seismic retrofit of RC columns,including the theories of FRP-strengthened RC columns,failure modes,the conclusions obtained through experimental investigations,finite element simulations,seismic performance evaluation and further developments of FRP reinforced columns.Displacement ductility coefficient and curvature ductility coefficient are two quantificational indices for seismic ductility design.It is also introduced three useful methods to calculate displacement ductility coefficient,and curvature enhancement coefficient is used to measure curvature ductility coefficient,it is expected to provide useful conclusions for further investigations.
2012, 42(2): 134-138,128.
doi: 10.13204/j.gyjz201202030
Abstract:
The ultraviolet rays have effects on characteristics of reinforced concrete column strengthened with BFRP.The compressive behavior of 16 reinforced concrete columns strengthened with BFRP exposed to ultraviolet rays was investigated.The results indicate that ultimate axial compressive strength of the column is decreased when the time of ultraviolet rays irradiation is increased according to lays of BFRP sheet and reinforcement pattern.After ultraviolet rays irradiating,the ductility of reinforced concrete column strengthened with BFRP is decreased,but it has little influence on failure pattern.
The ultraviolet rays have effects on characteristics of reinforced concrete column strengthened with BFRP.The compressive behavior of 16 reinforced concrete columns strengthened with BFRP exposed to ultraviolet rays was investigated.The results indicate that ultimate axial compressive strength of the column is decreased when the time of ultraviolet rays irradiation is increased according to lays of BFRP sheet and reinforcement pattern.After ultraviolet rays irradiating,the ductility of reinforced concrete column strengthened with BFRP is decreased,but it has little influence on failure pattern.
2012, 42(2): 139-143,91.
doi: 10.13204/j.gyjz201202031
Abstract:
This paper is a summary on the basis of data from relevant books of the concrete reinforcement technique at home and abroad,which introduces several common reinforcement concrete methods,expounds the reinforcing mechanism,the advantages and disadvantages,and engineering application of these methods.Especially the FRP reinforcement techniques at home and abroad are reviewed.On this basis the development trend of the reinforcement method is discussed finally.
This paper is a summary on the basis of data from relevant books of the concrete reinforcement technique at home and abroad,which introduces several common reinforcement concrete methods,expounds the reinforcing mechanism,the advantages and disadvantages,and engineering application of these methods.Especially the FRP reinforcement techniques at home and abroad are reviewed.On this basis the development trend of the reinforcement method is discussed finally.
2012, 42(2): 144-146,96.
doi: 10.13204/j.gyjz201202032
Abstract:
One industrial production workshop contains many heavy mezzanines,whose torsional vibration effect under bi-directional earthquake action is taken into account,hence the brace setting of the column which support the mezzanines and design of the wind-resistant column which is near to mezzanines are all different from common portal frame.Aiming at these difficulties,FEA software SAP 2000 is used for structural calculation and analysis,the efficient design methods are reached,good results are achieved after these methods are applied to this project.
One industrial production workshop contains many heavy mezzanines,whose torsional vibration effect under bi-directional earthquake action is taken into account,hence the brace setting of the column which support the mezzanines and design of the wind-resistant column which is near to mezzanines are all different from common portal frame.Aiming at these difficulties,FEA software SAP 2000 is used for structural calculation and analysis,the efficient design methods are reached,good results are achieved after these methods are applied to this project.
2012, 42(2): 147-151.
doi: 10.13204/j.gyjz201202033
Abstract:
The historical street of Qingdao Liyuan Building in Sifang Road is a better preservation street,which has very important architectural,artistic and historical values.With the development of urban construction,the street of Liyuan Building is gradually disappearing and needed protection.The paper mainly researches the material and non-material landscape of Qingdao Liyuan Building Street in order to make the street revive and continue the street's culture.
The historical street of Qingdao Liyuan Building in Sifang Road is a better preservation street,which has very important architectural,artistic and historical values.With the development of urban construction,the street of Liyuan Building is gradually disappearing and needed protection.The paper mainly researches the material and non-material landscape of Qingdao Liyuan Building Street in order to make the street revive and continue the street's culture.
