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2013 Vol. 43, No. 7
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2013, 43(7): 1-4,17.
doi: 10.13204/j.gyjz201307001
Abstract:
On condition of developing industrial heritage, it was studied the driving force of industrial heritage development, purpose is to development the influence factors of the driving force and the effect mechanism.This paper reviewed the change in the connotation of industrial heritage, at the same time, defined the theoretical basis and the scope of studying the industrial heritage.In this part of the research, this paper analyzed the formation and function condition of the driving force, through the project acceleration model, the composition of the positive and negative forces was got.In view of the above research, the following strategies to promote industry heritage development were given: perfect heritage management, reasonable matching resources;promote system innovation;strengthen market breed, attract innovative talents;import mature real estate and perfect project financing.
On condition of developing industrial heritage, it was studied the driving force of industrial heritage development, purpose is to development the influence factors of the driving force and the effect mechanism.This paper reviewed the change in the connotation of industrial heritage, at the same time, defined the theoretical basis and the scope of studying the industrial heritage.In this part of the research, this paper analyzed the formation and function condition of the driving force, through the project acceleration model, the composition of the positive and negative forces was got.In view of the above research, the following strategies to promote industry heritage development were given: perfect heritage management, reasonable matching resources;promote system innovation;strengthen market breed, attract innovative talents;import mature real estate and perfect project financing.
2013, 43(7): 5-8.
doi: 10.13204/j.gyjz201307002
Abstract:
It was summarized the landscape shaping strategy and artistic treatment in landscape methods under different cultural dimensions, by analyzing the inner cultural expression level of the contemporary western industrial sites landscape design.Thereby, it was also pointed out that the contemporary landscape design had got rid of the simple spatial game and the form play.Namely, the addition and expression of multi-culture-dimension of the form shaping were going to be recognized as the significant means of artistic creation of the industrial sites landscape design.
It was summarized the landscape shaping strategy and artistic treatment in landscape methods under different cultural dimensions, by analyzing the inner cultural expression level of the contemporary western industrial sites landscape design.Thereby, it was also pointed out that the contemporary landscape design had got rid of the simple spatial game and the form play.Namely, the addition and expression of multi-culture-dimension of the form shaping were going to be recognized as the significant means of artistic creation of the industrial sites landscape design.
2013, 43(7): 9-12.
doi: 10.13204/j.gyjz201307003
Abstract:
In China, the industrial heritage conservation and adaptive reuse are the new topic of urban regeneration and protection of cultural heritage.Based on the theoretical research and the analysis of practice.But also exists in the understanding of deviation practical work of China's industrial heritage protection and adaptive reuse, and taking the industrial heritage conservation and adaptive reuse in Guangzhou City as a case studu, it was proposed the thoughts and suggestions of China's industrial heritage protection and reuse.
In China, the industrial heritage conservation and adaptive reuse are the new topic of urban regeneration and protection of cultural heritage.Based on the theoretical research and the analysis of practice.But also exists in the understanding of deviation practical work of China's industrial heritage protection and adaptive reuse, and taking the industrial heritage conservation and adaptive reuse in Guangzhou City as a case studu, it was proposed the thoughts and suggestions of China's industrial heritage protection and reuse.
2013, 43(7): 13-17.
doi: 10.13204/j.gyjz201307004
Abstract:
Henan Province locates center of china, which is a very important place competed by the past dynasties regime and military strategist in ancient time.The replacement of dynasties has left behind rich heritages to Henan which had made big achievement in the historical and cultural heritage protection.In relative terms, Henan Province is defective and in a rather backward state in industry heritage protection.However, from the integrity of the history of the development of city, industrial heritage plays a connecting role in each historical cultural city of Henan Province.So the protection of modern industrial heritage should combine with the protection of historical and cultural city which shows the characteristic industrial heritage protection mode in Henan.
Henan Province locates center of china, which is a very important place competed by the past dynasties regime and military strategist in ancient time.The replacement of dynasties has left behind rich heritages to Henan which had made big achievement in the historical and cultural heritage protection.In relative terms, Henan Province is defective and in a rather backward state in industry heritage protection.However, from the integrity of the history of the development of city, industrial heritage plays a connecting role in each historical cultural city of Henan Province.So the protection of modern industrial heritage should combine with the protection of historical and cultural city which shows the characteristic industrial heritage protection mode in Henan.
2013, 43(7): 18-22.
doi: 10.13204/j.gyjz201307005
Abstract:
Luoyang is a famous historical cultural city in China, and it's also one of the most important old industrial bases of China.The numerous industrial building heritages in the city are the historica1 witness of Luoyang industrial development.It was expounded and analysesd that the developing process, character and current circumstances of the industrial building heritages in Luoyang.Combining with the historica1 culture character of city, it was also proposed a series of methods and strategies for the protection and renewal of the industrial building heritages in historical cultural city of Luoyang.
Luoyang is a famous historical cultural city in China, and it's also one of the most important old industrial bases of China.The numerous industrial building heritages in the city are the historica1 witness of Luoyang industrial development.It was expounded and analysesd that the developing process, character and current circumstances of the industrial building heritages in Luoyang.Combining with the historica1 culture character of city, it was also proposed a series of methods and strategies for the protection and renewal of the industrial building heritages in historical cultural city of Luoyang.
2013, 43(7): 23-25,8.
doi: 10.13204/j.gyjz201307006
Abstract:
Based upon regional features of Tangzha 1895 industrial heritage, it was proposed the purpose and developing concept or tactics for rejuvenation plan.In the predication of conserving historic space pattern, by integrating resource factors and establishing traditional handicraft creative industry with the necessary products, it was carried out the function transformation and rejuvenation of industrial heritage.
Based upon regional features of Tangzha 1895 industrial heritage, it was proposed the purpose and developing concept or tactics for rejuvenation plan.In the predication of conserving historic space pattern, by integrating resource factors and establishing traditional handicraft creative industry with the necessary products, it was carried out the function transformation and rejuvenation of industrial heritage.
2013, 43(7): 26-28.
doi: 10.13204/j.gyjz201307007
Abstract:
As a China's old industrial base, Tianjin has a large number of industrial heritages.Today the ancient city district is in the process of new development.The continuous development of service industry and sci-tech small-and medium-sized enterprises provides opportunities for the reuse and reconstruction of abundant industrial legacies.For most industrial architectures with historic and cultural value, how to deal with them is important.It was tried to make an in-depth analysis of abundant historic legacies of Tianjin and find out problems.Combining with the experiences of the foreign industrial architectural reconstruction and reuse, it was also tried to explore and perfect the notion and system for protection of industrial architectural legacy.
As a China's old industrial base, Tianjin has a large number of industrial heritages.Today the ancient city district is in the process of new development.The continuous development of service industry and sci-tech small-and medium-sized enterprises provides opportunities for the reuse and reconstruction of abundant industrial legacies.For most industrial architectures with historic and cultural value, how to deal with them is important.It was tried to make an in-depth analysis of abundant historic legacies of Tianjin and find out problems.Combining with the experiences of the foreign industrial architectural reconstruction and reuse, it was also tried to explore and perfect the notion and system for protection of industrial architectural legacy.
2013, 43(7): 33-36.
doi: 10.13204/j.gyjz201307009
Abstract:
The paper analyzes the historical, location and environmental, place and value characteristics of the small industrial plants in Suzhou, researched that the renewal model of these plants now is unitary and focuses on the cultural production, but the lack of cultural place to live and create.It proposes that the cultural update of these plants should consider the basis and opportunity of urban development, site characterization and requirement of people, and arrange rationally the double function of cultural production and cultural life in reason, thus forming three cultural renewal models.
The paper analyzes the historical, location and environmental, place and value characteristics of the small industrial plants in Suzhou, researched that the renewal model of these plants now is unitary and focuses on the cultural production, but the lack of cultural place to live and create.It proposes that the cultural update of these plants should consider the basis and opportunity of urban development, site characterization and requirement of people, and arrange rationally the double function of cultural production and cultural life in reason, thus forming three cultural renewal models.
2013, 43(7): 39-42.
doi: 10.13204/j.gyjz201307010
Abstract:
The helical ribbed bar is named HR bar.By 20 prestressed transmission length tests of prestressed HR bar, the effect of the main factors(effective prestress of HR bar, concrete tensile strength, diameter of HR bar and stirrup ratio) on prestressed transmission length was analyzed in detail.The analyses showed that the relative prestressed transmission length was proportional to the HR bar effective prestress, and was inversely proportional to the concrete tensile strength.On the basis of the experimental data, and based on the results of bond-anchorage tests of HR bar, the formula of prestressed transmission length for HR bar was proposed.
The helical ribbed bar is named HR bar.By 20 prestressed transmission length tests of prestressed HR bar, the effect of the main factors(effective prestress of HR bar, concrete tensile strength, diameter of HR bar and stirrup ratio) on prestressed transmission length was analyzed in detail.The analyses showed that the relative prestressed transmission length was proportional to the HR bar effective prestress, and was inversely proportional to the concrete tensile strength.On the basis of the experimental data, and based on the results of bond-anchorage tests of HR bar, the formula of prestressed transmission length for HR bar was proposed.
2013, 43(7): 43-51.
doi: 10.13204/j.gyjz201307011
Abstract:
In the nonlinear responses analysis of reinforced concrete structures, seismic wave input angles are usually simplified as paralleling to the principal axis of structures, and the problem of critical excitation angle is generally ignored.In this paper, three regular and symmetrical reinforced concrete typical spatial frames were employed as examples.Based on the OpenSees framework, flexibility method based fiber model was adopted to simulate the nonlinear responses of the columns under biaxial bending and varying axial forces.Nonlinear dynamic response analyses of the three frames under rare earthquake excitations with varying seismic wave input angles were carried out.The results show that for the regular and symmetrical spatial frames, the critical excitation angle of compressive strain of concrete fibers, tensile strain of steel fibers and ratio of plastic hinges at column ends are 45 and 135, the critical excitation angle of strain of concrete fiber and steel fiber, ratio of plastic hinges and rotation ductility at beam ends are principal axis of structures.The critical excitation angle of rotation ductility at column ends is not apparent.It cannot get critical energy dissipation characteristics of plastic hinges if seismic wave was input along the principal axis direction.
In the nonlinear responses analysis of reinforced concrete structures, seismic wave input angles are usually simplified as paralleling to the principal axis of structures, and the problem of critical excitation angle is generally ignored.In this paper, three regular and symmetrical reinforced concrete typical spatial frames were employed as examples.Based on the OpenSees framework, flexibility method based fiber model was adopted to simulate the nonlinear responses of the columns under biaxial bending and varying axial forces.Nonlinear dynamic response analyses of the three frames under rare earthquake excitations with varying seismic wave input angles were carried out.The results show that for the regular and symmetrical spatial frames, the critical excitation angle of compressive strain of concrete fibers, tensile strain of steel fibers and ratio of plastic hinges at column ends are 45 and 135, the critical excitation angle of strain of concrete fiber and steel fiber, ratio of plastic hinges and rotation ductility at beam ends are principal axis of structures.The critical excitation angle of rotation ductility at column ends is not apparent.It cannot get critical energy dissipation characteristics of plastic hinges if seismic wave was input along the principal axis direction.
2013, 43(7): 52-56.
doi: 10.13204/j.gyjz201307012
Abstract:
According to the effects of parameters of energy dissipation damper on its damping performance, the link element in SAP 2000 was used to simulate the energy dissipation damper, Wen model unit was used for friction damper, and Maxwell model unit was used for viscous damper, the interface program of MATLAB and SAP 2000 on the MATLAB software platform was established.Using time history analysis, it was respectively calculated the variation rules of structural control effect indexes along parameters when friction damper structure and viscous damper structure were under earthquake action, their better results were given and their control effects were compared.The results show that the energy dissipation damper parameters have important influences on its damping performance, when the parameters are reasonable enough, both friction damper and viscous damper can effectively control the structural displacement and acceleration, but have different control effects.
According to the effects of parameters of energy dissipation damper on its damping performance, the link element in SAP 2000 was used to simulate the energy dissipation damper, Wen model unit was used for friction damper, and Maxwell model unit was used for viscous damper, the interface program of MATLAB and SAP 2000 on the MATLAB software platform was established.Using time history analysis, it was respectively calculated the variation rules of structural control effect indexes along parameters when friction damper structure and viscous damper structure were under earthquake action, their better results were given and their control effects were compared.The results show that the energy dissipation damper parameters have important influences on its damping performance, when the parameters are reasonable enough, both friction damper and viscous damper can effectively control the structural displacement and acceleration, but have different control effects.
2013, 43(7): 57-60,51.
doi: 10.13204/j.gyjz201307013
Abstract:
This paper presents the results of experimental mechanical properties of metal pipeline strengthened by fiber reinforced polymers subjected to hydrostatic pressure.These metal pipelines were wrapped with different layers of CFRP sheets.The results show that the thicker layers of CFRP sheets, the higher the pressure bearing capacity.According to experimental results and thin-walled mechanics theory, the design equation of FRP thickness were set up when the metal pipeline was under elastic or plastic state.Based on the plasticity solution of thick wall cylinder in the polar coordinates, strength checking equation of strengthening structures was presented by different mechanical states.These design equations without iterative calculation are close to the experimental results and can be conveniently applied for actual projects.
This paper presents the results of experimental mechanical properties of metal pipeline strengthened by fiber reinforced polymers subjected to hydrostatic pressure.These metal pipelines were wrapped with different layers of CFRP sheets.The results show that the thicker layers of CFRP sheets, the higher the pressure bearing capacity.According to experimental results and thin-walled mechanics theory, the design equation of FRP thickness were set up when the metal pipeline was under elastic or plastic state.Based on the plasticity solution of thick wall cylinder in the polar coordinates, strength checking equation of strengthening structures was presented by different mechanical states.These design equations without iterative calculation are close to the experimental results and can be conveniently applied for actual projects.
2013, 43(7): 61-64.
doi: 10.13204/j.gyjz201307014
Abstract:
The mineral composition of the PRD's soft clay was analyzed quantitatively by using the X-ray diffraction method, and the total specific surface area of artificial soil samples and natural soil samples was tested by EGME method for studying the influence of mineral composition to the soil's strength characteristics.It is found that clay mineral(such as montmorillonite) is usually lamellar particle, has a lareg specific surface area, the adsorptive bound water membrane is thicker, intergranular direct contact between particles is less, the cementing actions connected by the combined water film is more obvious, and lubrication friction is formed intergranulas due to easy movement, which can be expressed by the lower shear strength and smaller angle of internal friction and the high cohesive force.And non-clay mineral particles(such as quartz) are usually granular or needle, specific surface area is small, adsorbed water film is thinner, cohesive force is low, and there is a direct contact with the friction angle between particles, so as to increase its strength.
The mineral composition of the PRD's soft clay was analyzed quantitatively by using the X-ray diffraction method, and the total specific surface area of artificial soil samples and natural soil samples was tested by EGME method for studying the influence of mineral composition to the soil's strength characteristics.It is found that clay mineral(such as montmorillonite) is usually lamellar particle, has a lareg specific surface area, the adsorptive bound water membrane is thicker, intergranular direct contact between particles is less, the cementing actions connected by the combined water film is more obvious, and lubrication friction is formed intergranulas due to easy movement, which can be expressed by the lower shear strength and smaller angle of internal friction and the high cohesive force.And non-clay mineral particles(such as quartz) are usually granular or needle, specific surface area is small, adsorbed water film is thinner, cohesive force is low, and there is a direct contact with the friction angle between particles, so as to increase its strength.
2013, 43(7): 65-67,75.
doi: 10.13204/j.gyjz201307015
Abstract:
For the loess widely distributed in Ningxia, high salt content, strong structure, and other problems of loess foundation are becoming outstanding day by day.Taking dry density, moisture content, salt content as factors, orthogonal test scheme L9(34) was designed, unconfined compressive strength test was done by triaxial apparatus, the impact law of factors in the structural strength and structural parameters of loess was studied.The results showed that the structural property of loess increased with the increase of dry density and salt content, and decreased with the increase of moisture content.No matter what moisture content was high or low, soluble salt was one of the important factors that influences structural property.
For the loess widely distributed in Ningxia, high salt content, strong structure, and other problems of loess foundation are becoming outstanding day by day.Taking dry density, moisture content, salt content as factors, orthogonal test scheme L9(34) was designed, unconfined compressive strength test was done by triaxial apparatus, the impact law of factors in the structural strength and structural parameters of loess was studied.The results showed that the structural property of loess increased with the increase of dry density and salt content, and decreased with the increase of moisture content.No matter what moisture content was high or low, soluble salt was one of the important factors that influences structural property.
2013, 43(7): 68-71.
doi: 10.13204/j.gyjz201307016
Abstract:
Based on the actual situation of engineering, the clay core impervious material of the soil core wall rock fill dam was studied, the influences of different confining stresses considered.Through dynamic triaxial test, dynamic characteristics of the clay core impervious material under 5 selected confining were studied;the impacts of confining stresses on it were concluded.In the range of analyzed confining stress, the dynamic elastic modulus of the clay core impervious material was increased markedly with an increase of confining stress;power correlations between its two parameters containing the maximum dynamic elastic modulus and the average principal stress were obtained, the maximum dynamic elastic modulus of the clay core impervious material was increased markedly with an increase of the average principal stress by exponential form;the damping ratio curve and dynamic shear modulus ratio curves were normalized well under diferent confining stress conditions.
Based on the actual situation of engineering, the clay core impervious material of the soil core wall rock fill dam was studied, the influences of different confining stresses considered.Through dynamic triaxial test, dynamic characteristics of the clay core impervious material under 5 selected confining were studied;the impacts of confining stresses on it were concluded.In the range of analyzed confining stress, the dynamic elastic modulus of the clay core impervious material was increased markedly with an increase of confining stress;power correlations between its two parameters containing the maximum dynamic elastic modulus and the average principal stress were obtained, the maximum dynamic elastic modulus of the clay core impervious material was increased markedly with an increase of the average principal stress by exponential form;the damping ratio curve and dynamic shear modulus ratio curves were normalized well under diferent confining stress conditions.
2013, 43(7): 72-75.
doi: 10.13204/j.gyjz201307017
Abstract:
Four PHC pipe piles were tested on a seismic performance under low cyclic loading.The influence of pile core and configurating non-prestressed reinforcement on the failure characteristic, hysteretic performance, skeleton curve, ductility performance, and rigidity degradation of pipe piles were analyzed.The results indicated that the deformation capacity of pipe piles could be improved by pile core;the hysteretic performance, ductility performance and energy dissipation capacity of pipe piles could be improved more effectively by configurating some non-prestressed reinforcement.
Four PHC pipe piles were tested on a seismic performance under low cyclic loading.The influence of pile core and configurating non-prestressed reinforcement on the failure characteristic, hysteretic performance, skeleton curve, ductility performance, and rigidity degradation of pipe piles were analyzed.The results indicated that the deformation capacity of pipe piles could be improved by pile core;the hysteretic performance, ductility performance and energy dissipation capacity of pipe piles could be improved more effectively by configurating some non-prestressed reinforcement.
2013, 43(7): 76-79,85.
doi: 10.13204/j.gyjz201307018
Abstract:
Through the finite element analysis of an imaginary embankment under fast loading, in order to examine the difference of consolidation deformation results predicted by the three plastic-models(MCC, 3DMCC, and ANIS-MCC).The research results showed that the variation trendency of the deformation and pore pressure were mainly the same before the destroy of the embankment, however, when it necessicary, especially to improve the prediction accuracy of the ground deformation at foot, it was best to use the more complex model that could reflact the anisotropic yield characteristics of the soil, such as ANIS-MCC.
Through the finite element analysis of an imaginary embankment under fast loading, in order to examine the difference of consolidation deformation results predicted by the three plastic-models(MCC, 3DMCC, and ANIS-MCC).The research results showed that the variation trendency of the deformation and pore pressure were mainly the same before the destroy of the embankment, however, when it necessicary, especially to improve the prediction accuracy of the ground deformation at foot, it was best to use the more complex model that could reflact the anisotropic yield characteristics of the soil, such as ANIS-MCC.
2013, 43(7): 80-85.
doi: 10.13204/j.gyjz201307019
Abstract:
Engineered cementitious composite(ECC) can significantly improve the seismic performance and durability of concrete structures, which has pseudo strain hardening and multiple cracking performances.Through 32 groups of 192 specimens for doing orthogonal test of compressive strength of ECC, it was studied the cube compression failure process, and further research on water-binder ratio, fiber content by volume, fly ash content and sand-binder ratio on the size effect of ECC cube compressive strength.The test results show that as PVA fiber content increases, ECC compressive toughness is improved obviously;water-binder ratio and fiber content are the main factors which affect the ECC compressive strength and size effect.When water-binder ratio increases, the compressive strength of ECC materials decreases and size effect coefficient increases.Fiber content increases, the compressive strength of test block increases and the size effect coefficient increases.The bending tests show that the fiber content by volume increases, the ECC flexural strength of the composite increases obviously.
Engineered cementitious composite(ECC) can significantly improve the seismic performance and durability of concrete structures, which has pseudo strain hardening and multiple cracking performances.Through 32 groups of 192 specimens for doing orthogonal test of compressive strength of ECC, it was studied the cube compression failure process, and further research on water-binder ratio, fiber content by volume, fly ash content and sand-binder ratio on the size effect of ECC cube compressive strength.The test results show that as PVA fiber content increases, ECC compressive toughness is improved obviously;water-binder ratio and fiber content are the main factors which affect the ECC compressive strength and size effect.When water-binder ratio increases, the compressive strength of ECC materials decreases and size effect coefficient increases.Fiber content increases, the compressive strength of test block increases and the size effect coefficient increases.The bending tests show that the fiber content by volume increases, the ECC flexural strength of the composite increases obviously.
2013, 43(7): 86-90,64.
doi: 10.13204/j.gyjz201307020
Abstract:
In order to study the damage characteristics and deterioration mechanism of concrete in difference structural regions, the appearance, mechanical properties, carbonation depth, distribution of free chloride content, apparent chloride ion diffusion coefficient, alkali content and the cover thickness of concrete for plate girder(atmosphere zone), cross beam(tidal zone) and square pile(underwater zone), at the typical region of a marine dock in Ningbo, were tested.The test data show that the structural concrete in the atmosphere and tidal zone have a better compressive strength state, while concrete in underwater zone has a poor compressive strength state, the carbonation depth and Dne/Dnd of the cover thickness are decreased from upper part to lower part, atmosphere zonetidal zoneunderwater zone, the distribution law of free chloride content, apparent chloride diffusion coefficient(Da) and alkali content of concrete are underwater zone tidal zoneatmosphere zone.The conclusions are drawn that CO2 of erosion action at atmosphere zone results in deterioration of the cover thickness, the combined action of harmful chloride ion and CO2 erosion lead to steel corrosion and deterioration of cover thickness at the tidal zone, due to the chloride ion and salt permeate into concrete of underwater zone, the coupling effect of chloride ion and high salt concentration accelerate the deterioration of cover thickness at the underwater zone.
In order to study the damage characteristics and deterioration mechanism of concrete in difference structural regions, the appearance, mechanical properties, carbonation depth, distribution of free chloride content, apparent chloride ion diffusion coefficient, alkali content and the cover thickness of concrete for plate girder(atmosphere zone), cross beam(tidal zone) and square pile(underwater zone), at the typical region of a marine dock in Ningbo, were tested.The test data show that the structural concrete in the atmosphere and tidal zone have a better compressive strength state, while concrete in underwater zone has a poor compressive strength state, the carbonation depth and Dne/Dnd of the cover thickness are decreased from upper part to lower part, atmosphere zonetidal zoneunderwater zone, the distribution law of free chloride content, apparent chloride diffusion coefficient(Da) and alkali content of concrete are underwater zone tidal zoneatmosphere zone.The conclusions are drawn that CO2 of erosion action at atmosphere zone results in deterioration of the cover thickness, the combined action of harmful chloride ion and CO2 erosion lead to steel corrosion and deterioration of cover thickness at the tidal zone, due to the chloride ion and salt permeate into concrete of underwater zone, the coupling effect of chloride ion and high salt concentration accelerate the deterioration of cover thickness at the underwater zone.
2013, 43(7): 91-95.
doi: 10.13204/j.gyjz201307021
Abstract:
Based on the experiment of circular timber columns made of deal and fir strengthened by near-surface mounted CFRP sheets under axial compression, the failure modes, axial bearing capacity, and loading-strain curves were analyzed.The results showed that comparing with the specimens without being strengthened by CFRP sheets, the axial bearing capacity of the specimens strengthened by CFRP sheets was improved.The axial bearing capacity of deal specimens was improved by 6.9%~24.1%, and the axial bearing capacity of fir specimens was improved by 24.1%~63.2%.Based on experimental data, the computing formulas of axial bearing capacity of circular timber columns made of deal and fir strengthened by near-surface mounted CFRP sheets were presented respectively.
Based on the experiment of circular timber columns made of deal and fir strengthened by near-surface mounted CFRP sheets under axial compression, the failure modes, axial bearing capacity, and loading-strain curves were analyzed.The results showed that comparing with the specimens without being strengthened by CFRP sheets, the axial bearing capacity of the specimens strengthened by CFRP sheets was improved.The axial bearing capacity of deal specimens was improved by 6.9%~24.1%, and the axial bearing capacity of fir specimens was improved by 24.1%~63.2%.Based on experimental data, the computing formulas of axial bearing capacity of circular timber columns made of deal and fir strengthened by near-surface mounted CFRP sheets were presented respectively.
2013, 43(7): 96-100.
doi: 10.13204/j.gyjz201307022
Abstract:
The axial forces of vertical struts of the main beam and the plate bottom for a super high or large-span formwork support was measured on site during the period of casting concrete.The results showed that axial forces of vertical struts increased significantly after pouring the concrete above them, pumping had not only horizontal impact force but also vertical impact force, axial forces of vertical struts were uneven along the height, yet it was still safe to calculate the axial forces of the vertical struts by the regional load calculation method in the current code.There was an interaction between each tube of the formwork support, pumping and concrete placing route would induce horizontal force that would produce unfavorable effect on the stability of formwork support.According to the measured results, the present design and calculation method should be modified, and several effective suggestions on the construction of super high or large-span formwork support with fastener steel tube were provided.
The axial forces of vertical struts of the main beam and the plate bottom for a super high or large-span formwork support was measured on site during the period of casting concrete.The results showed that axial forces of vertical struts increased significantly after pouring the concrete above them, pumping had not only horizontal impact force but also vertical impact force, axial forces of vertical struts were uneven along the height, yet it was still safe to calculate the axial forces of the vertical struts by the regional load calculation method in the current code.There was an interaction between each tube of the formwork support, pumping and concrete placing route would induce horizontal force that would produce unfavorable effect on the stability of formwork support.According to the measured results, the present design and calculation method should be modified, and several effective suggestions on the construction of super high or large-span formwork support with fastener steel tube were provided.
2013, 43(7): 101-104.
doi: 10.13204/j.gyjz201307023
Abstract:
Based on Z1-section of Tianjin cultural centre transport hub, the model of super deep reinforcement cage for diaphragm wall was built by the ABAQUS finite element analysis software and site monitoring method.It was mainly studied one-time hoisting process of 1 shape 55 m reinforcement cage in different conditions.ABAQUS could predict the construction preparation and construction process, and also provide hoisting parameters for the actual hoisting procedure.The predicted results could analyze potential problems and risks of the actual hoisting process.
Based on Z1-section of Tianjin cultural centre transport hub, the model of super deep reinforcement cage for diaphragm wall was built by the ABAQUS finite element analysis software and site monitoring method.It was mainly studied one-time hoisting process of 1 shape 55 m reinforcement cage in different conditions.ABAQUS could predict the construction preparation and construction process, and also provide hoisting parameters for the actual hoisting procedure.The predicted results could analyze potential problems and risks of the actual hoisting process.
2013, 43(7): 105-109,138.
doi: 10.13204/j.gyjz201307024
Abstract:
A comparison of shear capacity calculation method of non-prestressed reinforced concrete beams with stirrups was carried out among GB 50010-2010, ACI318M-08 and EN1992-1-1:2004.The effects of the concrete strength, shear-span ratio, longitudinal reinforcement ratio on the shear strength were also studied.According to domestic and internationa 219 experimental results under pointload of the shear capacity of simply supported reinforced concrete beams, the calculation and experimental values of the standard shear capacity are compared and analysed among different countries.The minimum or maximum stirrup ratios were comparatively analyzed.The results show that shear capacity for reinforced concrete beams with stirrups designed according to European code is greater than Chinese code, but ACI code is the smallest.For the minimum ratios of stirrups, European code is greater than Chinese code and ACI code, ACI code is the smallest.According to the comparison, it is indicated that there are some unreasonable problems for shear capacity calculation in Chinese code, and the modification should be further adopted.
A comparison of shear capacity calculation method of non-prestressed reinforced concrete beams with stirrups was carried out among GB 50010-2010, ACI318M-08 and EN1992-1-1:2004.The effects of the concrete strength, shear-span ratio, longitudinal reinforcement ratio on the shear strength were also studied.According to domestic and internationa 219 experimental results under pointload of the shear capacity of simply supported reinforced concrete beams, the calculation and experimental values of the standard shear capacity are compared and analysed among different countries.The minimum or maximum stirrup ratios were comparatively analyzed.The results show that shear capacity for reinforced concrete beams with stirrups designed according to European code is greater than Chinese code, but ACI code is the smallest.For the minimum ratios of stirrups, European code is greater than Chinese code and ACI code, ACI code is the smallest.According to the comparison, it is indicated that there are some unreasonable problems for shear capacity calculation in Chinese code, and the modification should be further adopted.
2013, 43(7): 110-114.
doi: 10.13204/j.gyjz201307025
Abstract:
The relationship between safety of building structures and economic development was studied.The impact of economic development recently in china on the safety level adjustment for building structures was analyzed.A comparison of economy development and safety of concrete building structures in China, United States and United Kingdom was made.The analysis indicated that as a consequence of rapid development of Chinese economy, the safety level of building structures upgraded in 2000.The cost for construction in unit area in China is far lower than that in US and slightly higher than UK.The safety level with respect to reinforced building structures is lower than US and UK in the order of 20% and 10% respectively.It concluded that although the safety level of building structures relate closely with the economic development, yet there should be a upper-limit which depends, on the balance of economy of a country.
The relationship between safety of building structures and economic development was studied.The impact of economic development recently in china on the safety level adjustment for building structures was analyzed.A comparison of economy development and safety of concrete building structures in China, United States and United Kingdom was made.The analysis indicated that as a consequence of rapid development of Chinese economy, the safety level of building structures upgraded in 2000.The cost for construction in unit area in China is far lower than that in US and slightly higher than UK.The safety level with respect to reinforced building structures is lower than US and UK in the order of 20% and 10% respectively.It concluded that although the safety level of building structures relate closely with the economic development, yet there should be a upper-limit which depends, on the balance of economy of a country.
2013, 43(7): 115-119.
doi: 10.13204/j.gyjz201307026
Abstract:
The roof purlin of a light-weight steel structure with portal frame is a kind of snow load sensitive component.The Load Code for the Design of Building Structures(GB 500092012) has more explicit and detailed provisions for the value of snow load.Through the comparison and analysis of the new load code and the old load code, the rules and characteristics of the new load code about basic snow load values and roofing snow distribution coefficients in the design of the roof purlin of light-weight steel structure with portal frame were clarified, and the main points of the anti-snow load design of the purlin were summarized.Finally the applicability of the snow load value in the new load code for purlin design was verified through the analysis of a specific snow-caused accident.
The roof purlin of a light-weight steel structure with portal frame is a kind of snow load sensitive component.The Load Code for the Design of Building Structures(GB 500092012) has more explicit and detailed provisions for the value of snow load.Through the comparison and analysis of the new load code and the old load code, the rules and characteristics of the new load code about basic snow load values and roofing snow distribution coefficients in the design of the roof purlin of light-weight steel structure with portal frame were clarified, and the main points of the anti-snow load design of the purlin were summarized.Finally the applicability of the snow load value in the new load code for purlin design was verified through the analysis of a specific snow-caused accident.
2013, 43(7): 120-124.
doi: 10.13204/j.gyjz201307027
Abstract:
A total of 3 concrete filled steel tubular short columns and 6 polypropylene(PP) fiber mortar filled steel tubular short columns were tested under axial compression dynamic load.The influence of the strain rate and diameter thickness ratio on the dynamic performance of the PP fiber mortar filled steel tubular short columns was investigated.The test results showed that the ultimate bearing capacity and the initial elastic modulus were increased by 5.80% and 42.8% respectively, while the strain of peak load was decreased by 6.77% when the two millimetres of PP fiber mortar filled steel tubular short column with the strain rate of =10-4 s-1 was compared with the strain rate of =10-5 s-1.In the scope of test parameters, strain rate was more effective to PP fiber mortar filled steel tubular short column than concrete filled steel tubular short column in the scope of ultimate bearing capacity and the peak load strain, while the result was opposed in the elastic modulus.
A total of 3 concrete filled steel tubular short columns and 6 polypropylene(PP) fiber mortar filled steel tubular short columns were tested under axial compression dynamic load.The influence of the strain rate and diameter thickness ratio on the dynamic performance of the PP fiber mortar filled steel tubular short columns was investigated.The test results showed that the ultimate bearing capacity and the initial elastic modulus were increased by 5.80% and 42.8% respectively, while the strain of peak load was decreased by 6.77% when the two millimetres of PP fiber mortar filled steel tubular short column with the strain rate of =10-4 s-1 was compared with the strain rate of =10-5 s-1.In the scope of test parameters, strain rate was more effective to PP fiber mortar filled steel tubular short column than concrete filled steel tubular short column in the scope of ultimate bearing capacity and the peak load strain, while the result was opposed in the elastic modulus.
MODEL TEST ON THE ARCH-GIRDER HOLDING REGION OF HALF-THROUGH CONTINUOUS BEAM-ARCH COMBINATION BRIDGE
2013, 43(7): 125-129,100.
doi: 10.13204/j.gyjz201307028
Abstract:
For the arch-girder holding region of the half-through continuous beam-arch combination bridge, the structure and force are complicated.Investigations of force transmission and stress distribution of the arch-girder consolidation zone were carried out by finite element method and a model test based on a high-speed railway bridge, and a 1∶4 model was tested.The principle of model scale, the determination of load system and the arrangement of the measuring were briefly introuduced.The finite element and experimental analyses indicate that the cross beam can result in lead the arch rib out-of-plane bending, and let the arch rib filled concrete and web plate stress of the cross beam side be greater than that of the other side without cross beam;and the stress concentration occur at the connection of the beam and arch rib, as well as the girder and arch rib connection.The arch-girder holding zone stress is low, the structure behaves almost elastic state.The force transmission and stress distribution for the structure are reasonable, which can meet the requirement of carrying capacity.
For the arch-girder holding region of the half-through continuous beam-arch combination bridge, the structure and force are complicated.Investigations of force transmission and stress distribution of the arch-girder consolidation zone were carried out by finite element method and a model test based on a high-speed railway bridge, and a 1∶4 model was tested.The principle of model scale, the determination of load system and the arrangement of the measuring were briefly introuduced.The finite element and experimental analyses indicate that the cross beam can result in lead the arch rib out-of-plane bending, and let the arch rib filled concrete and web plate stress of the cross beam side be greater than that of the other side without cross beam;and the stress concentration occur at the connection of the beam and arch rib, as well as the girder and arch rib connection.The arch-girder holding zone stress is low, the structure behaves almost elastic state.The force transmission and stress distribution for the structure are reasonable, which can meet the requirement of carrying capacity.
2013, 43(7): 130-134.
doi: 10.13204/j.gyjz201307029
Abstract:
A station house is a single-layer reticulated shell structure, wind tunnel test results show that the wind in the roof surface localized disturbance and turbulent flow and the formation of convolution vortex, so the roof is subjected mainly to lift the most disadvantageous position is in the steep end bottom.For a large-span roof structure of symmetric overall structure and asymmetric partial structure, even under the action of symmetric wind, the effect of wind on the integral roof is unbalanced, which is produced mainly by the nonuniform surface structure.
A station house is a single-layer reticulated shell structure, wind tunnel test results show that the wind in the roof surface localized disturbance and turbulent flow and the formation of convolution vortex, so the roof is subjected mainly to lift the most disadvantageous position is in the steep end bottom.For a large-span roof structure of symmetric overall structure and asymmetric partial structure, even under the action of symmetric wind, the effect of wind on the integral roof is unbalanced, which is produced mainly by the nonuniform surface structure.
2013, 43(7): 135-138.
doi: 10.13204/j.gyjz201307030
Abstract:
It can be known from the comparison of relevant characteristics of the optimized design by penalty function method for a 30 m span tapered portal frame to the design by the conventional method.So as to achieve the ideal value of the design objective function through the interaction of relevant design parameters for the joints of the inner bearing capacity and the controlled sections.It can be seen by the contrast of relevant characteristics of examples that generally 15%~30% energy can be saved by the optimized design.At the same time, it is proposed that the choice of several reasonable parameters needing attention during optimizing a design.
It can be known from the comparison of relevant characteristics of the optimized design by penalty function method for a 30 m span tapered portal frame to the design by the conventional method.So as to achieve the ideal value of the design objective function through the interaction of relevant design parameters for the joints of the inner bearing capacity and the controlled sections.It can be seen by the contrast of relevant characteristics of examples that generally 15%~30% energy can be saved by the optimized design.At the same time, it is proposed that the choice of several reasonable parameters needing attention during optimizing a design.
2013, 43(7): 139-144.
doi: 10.13204/j.gyjz201307031
Abstract:
A terrace house located on coastal beach of Shandong Province, with waffle-slab raft foundation, is founded on 3.5~5.0 m thick miscellaneous fill treated with dynamic compaction, which is followed by 3.0 thick mucky soil, forming a hard-soft double-layered foundation.When the construction of the building was approaching completion, large settlement and differential settlement occurred.The causes of the settlements were analyzed from the geological conditions, foundation treatment measures, the design concept and construction procedure, and through comparing calculated settlement with the measured one, the experience coefficient for the settlement was obtained.In order to control post-construction settlement and differential settlement, micro-pile was adopted and its effectiveness is illustrated by comparing the calculated settlement of raft foundation to the piled raft foundation with a few of piles as settlement reducer.The foundation deformation tended to be stable within two weeks after the ground treatment completion, thus achieving the planned expectation.
A terrace house located on coastal beach of Shandong Province, with waffle-slab raft foundation, is founded on 3.5~5.0 m thick miscellaneous fill treated with dynamic compaction, which is followed by 3.0 thick mucky soil, forming a hard-soft double-layered foundation.When the construction of the building was approaching completion, large settlement and differential settlement occurred.The causes of the settlements were analyzed from the geological conditions, foundation treatment measures, the design concept and construction procedure, and through comparing calculated settlement with the measured one, the experience coefficient for the settlement was obtained.In order to control post-construction settlement and differential settlement, micro-pile was adopted and its effectiveness is illustrated by comparing the calculated settlement of raft foundation to the piled raft foundation with a few of piles as settlement reducer.The foundation deformation tended to be stable within two weeks after the ground treatment completion, thus achieving the planned expectation.
2013, 43(7): 145-149.
doi: 10.13204/j.gyjz201307032
Abstract:
The combination of skeleton structure and tension membrane structure is adopted in the roof of Lidu New District Sport Center Stadium which comprises two crescent-type spatial structures.The main structure is composed of spatial truss, which consists of large tension bars and compression bars, and arch truss with 245.6 m span.The difficulty in this project is the outerplanar bending of the arch truss due to the limitation of the site.Combining the specific structure design, the static and dynamic performance and optimizations of structural design were introduced in detail.The effects of temperature and wind load on large-span structure was also analyzed.
The combination of skeleton structure and tension membrane structure is adopted in the roof of Lidu New District Sport Center Stadium which comprises two crescent-type spatial structures.The main structure is composed of spatial truss, which consists of large tension bars and compression bars, and arch truss with 245.6 m span.The difficulty in this project is the outerplanar bending of the arch truss due to the limitation of the site.Combining the specific structure design, the static and dynamic performance and optimizations of structural design were introduced in detail.The effects of temperature and wind load on large-span structure was also analyzed.
2013, 43(7): 150-154.
doi: 10.13204/j.gyjz201307033
Abstract:
Shenzhen Metro line 3 passes through the Guangzhou-Shenzhen railway viaduct so it is necessary to underpin the piled foundation of existing bridge and man-hole-piles are used, the project is in a saturated, loose sand stratum with high permeability and high confined water head.Two-shot grouting was used to form a waterproof curtain.By means of the experiment, determines the proportion was determined reasonably, the construction method was grasped and inspected the grouting effect inspected.The results of test and construction show that cement and water glass two-shot grouting in the saturated loose sand layer can increase strength significantly, and seepage coefficient be decreased by 102~103 magnitude, the hydraulic fracture pressure of the soil curtain is more than 0.3 MPa and surface deformation is small, thus meeting the waterproof requirement of 2 m diameter and 24 m long man-hole-pile completely.
Shenzhen Metro line 3 passes through the Guangzhou-Shenzhen railway viaduct so it is necessary to underpin the piled foundation of existing bridge and man-hole-piles are used, the project is in a saturated, loose sand stratum with high permeability and high confined water head.Two-shot grouting was used to form a waterproof curtain.By means of the experiment, determines the proportion was determined reasonably, the construction method was grasped and inspected the grouting effect inspected.The results of test and construction show that cement and water glass two-shot grouting in the saturated loose sand layer can increase strength significantly, and seepage coefficient be decreased by 102~103 magnitude, the hydraulic fracture pressure of the soil curtain is more than 0.3 MPa and surface deformation is small, thus meeting the waterproof requirement of 2 m diameter and 24 m long man-hole-pile completely.
2013, 43(7): 155-158.
doi: 10.13204/j.gyjz201307034
Abstract:
The development of BIM in China is still at the primary stage.The scope of application is mainly limited within the design phase, whose purpose is to build a three-dimension model, which is far from what is expected.Based on the present situation, it was analyzed the application concept of BIM at the design phase in order to promote effectively the use of BIM, and then pointed out the problems during the use of BIM, which were also summarized for optimizing the design process.
The development of BIM in China is still at the primary stage.The scope of application is mainly limited within the design phase, whose purpose is to build a three-dimension model, which is far from what is expected.Based on the present situation, it was analyzed the application concept of BIM at the design phase in order to promote effectively the use of BIM, and then pointed out the problems during the use of BIM, which were also summarized for optimizing the design process.
