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2014 Vol. 44, No. 03
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2014, 44(03): 1-5.
doi: 10.13204/j.gyjz201403003
Abstract:
Application of high strength steel in steel buildings can promote the development of science，and create significant social and economic results，which the development trend of steel structure． For promoting the application of high strength steel in steel structure，it is discussed its advantages，the present research situation at home and abroad，engineering application，and the existing technique problems． Which can provide the technique references for the application of high strength steel in steel structure in China．
Application of high strength steel in steel buildings can promote the development of science，and create significant social and economic results，which the development trend of steel structure． For promoting the application of high strength steel in steel structure，it is discussed its advantages，the present research situation at home and abroad，engineering application，and the existing technique problems． Which can provide the technique references for the application of high strength steel in steel structure in China．
2014, 44(03): 6-10.
doi: 10.13204/j.gyjz201403004
Abstract:
The fatigue performance of high strength steel was studied so as to discuss the relevant steel fatigue design provisions of the code for design of steel structures and help to promote the application of high strength steel in civil engineering． which provided data reference for following up research． A number of axial tensile fatigue tests by conventional test methods using Q460D plate specimens were conducted and the S-N curves attached to the fatigue performance were drawn． The test results showed that the fatigue performance of these Q460D steel specimens was very sensitive to the fatigue load and the data discreteness was considerable． The fatigue strength of Q460D under 2 million times loading was greater than that calculate by Code for Design of Steel Structuares(GB 500172003)．
The fatigue performance of high strength steel was studied so as to discuss the relevant steel fatigue design provisions of the code for design of steel structures and help to promote the application of high strength steel in civil engineering． which provided data reference for following up research． A number of axial tensile fatigue tests by conventional test methods using Q460D plate specimens were conducted and the S-N curves attached to the fatigue performance were drawn． The test results showed that the fatigue performance of these Q460D steel specimens was very sensitive to the fatigue load and the data discreteness was considerable． The fatigue strength of Q460D under 2 million times loading was greater than that calculate by Code for Design of Steel Structuares(GB 500172003)．
2014, 44(03): 11-18.
doi: 10.13204/j.gyjz201403005
Abstract:
To study the compression-bending stability of Q690 high performance steel tubular in power transfer tower， 15 welded tubular specimens of 3 various cross sections with different slenderness which were designed and fabricated by 6 and 8 mm-thick Q690 high performance steel sheets made in China． The tests of the specimens were conducted under static moment loading with constant axial compression，and moment-axial displacement curves were derived． Based on the test results，the specimensglobal behaviors were analyzed，including the load-carrying capacity，the buckling mode and the failure state，and Chinese specification and American code for design tubular structure in power transfer tower were adopted to verify． The conclusion shows that，buckling types depend on slenderness ratio and the ratio of diameter to thickness，as slenderness ratio decreases or the ratio of diameter to thickness increases，buckling type transfers from global buckling to local buckling; buckling stress states relay on the ratio of diameter to thickness， when the ratio of diameter to thickness decreases，buckling stress state transfers from elasticity to elastoplasticity; all code formulas are conservative，while all analysis results agree well with the test，which further validates that relevant code formulas and stability coefficient are feasible and rational to guide the practice．
To study the compression-bending stability of Q690 high performance steel tubular in power transfer tower， 15 welded tubular specimens of 3 various cross sections with different slenderness which were designed and fabricated by 6 and 8 mm-thick Q690 high performance steel sheets made in China． The tests of the specimens were conducted under static moment loading with constant axial compression，and moment-axial displacement curves were derived． Based on the test results，the specimensglobal behaviors were analyzed，including the load-carrying capacity，the buckling mode and the failure state，and Chinese specification and American code for design tubular structure in power transfer tower were adopted to verify． The conclusion shows that，buckling types depend on slenderness ratio and the ratio of diameter to thickness，as slenderness ratio decreases or the ratio of diameter to thickness increases，buckling type transfers from global buckling to local buckling; buckling stress states relay on the ratio of diameter to thickness， when the ratio of diameter to thickness decreases，buckling stress state transfers from elasticity to elastoplasticity; all code formulas are conservative，while all analysis results agree well with the test，which further validates that relevant code formulas and stability coefficient are feasible and rational to guide the practice．
2014, 44(03): 19-22.
doi: 10.13204/j.gyjz201403006
Abstract:
The research on mechanical property and microstructure of architectural steel with high strength and low yield ratio has been done，and the results show that rolled steel meets the technical requirements and has favorable impact property． The strength of Nb steel is slightly lower than the technical requirements，which can meet them after its tempering． The ideal start cooling temperature for Nb steel is 750 ℃ or 800 ℃，that of the rest steels is 750 ℃． There are many precipitated phases homogeneous distribution in Nb + Mo steel that mainly are flocculent and irregular particles and their size is generally smaller than 250 nm． The flocculation phase composition is mainly Nb as well as a spot of Ti，that of particles is mainly Nb and Ti，their sizes are 10 ～ 25 nm and 50 ～ 170 nm respectively．
The research on mechanical property and microstructure of architectural steel with high strength and low yield ratio has been done，and the results show that rolled steel meets the technical requirements and has favorable impact property． The strength of Nb steel is slightly lower than the technical requirements，which can meet them after its tempering． The ideal start cooling temperature for Nb steel is 750 ℃ or 800 ℃，that of the rest steels is 750 ℃． There are many precipitated phases homogeneous distribution in Nb + Mo steel that mainly are flocculent and irregular particles and their size is generally smaller than 250 nm． The flocculation phase composition is mainly Nb as well as a spot of Ti，that of particles is mainly Nb and Ti，their sizes are 10 ～ 25 nm and 50 ～ 170 nm respectively．
2014, 44(03): 23-27.
doi: 10.13204/j.gyjz201403007
Abstract:
It was researched the ultimate bearing capacity of H steel columns under axial compression by means of FE software． The results shows that the residual stress peak in the flange and has the biggest effect on the H steel column，the stress peak at the midpoint of the flange has a less effect，and the peak effect is the minimum in the midpoint of the web． the stability factor of Q550 high strength steel components by the existing design code of steel structures is slightly conservative．
It was researched the ultimate bearing capacity of H steel columns under axial compression by means of FE software． The results shows that the residual stress peak in the flange and has the biggest effect on the H steel column，the stress peak at the midpoint of the flange has a less effect，and the peak effect is the minimum in the midpoint of the web． the stability factor of Q550 high strength steel components by the existing design code of steel structures is slightly conservative．
2014, 44(03): 28-32.
doi: 10.13204/j.gyjz201403008
Abstract:
High performance structural steel features high strength，good ductility and material-saving，which has a superior performance and remarkable economic benefits，it is getting more popularization and application in tall and large span buildings as well as highway bridges． Developed by WISCO Q550GJC is a new type of building high performance structural steel． So far，it has not been applied in the field of domestic construction steel structure． On the basis of the research in necessary test such as steel weldability and the selection of welding material，it was qualified and summarized the WPS of Q550GJC including SAW，SMAW，GMAW and FCAW，which could meet the requirements of national standard Code for Welding of Steel Structures GB506612011． The WPS provided the beneficial reference for the future engineering application and the development of relevant standards．
High performance structural steel features high strength，good ductility and material-saving，which has a superior performance and remarkable economic benefits，it is getting more popularization and application in tall and large span buildings as well as highway bridges． Developed by WISCO Q550GJC is a new type of building high performance structural steel． So far，it has not been applied in the field of domestic construction steel structure． On the basis of the research in necessary test such as steel weldability and the selection of welding material，it was qualified and summarized the WPS of Q550GJC including SAW，SMAW，GMAW and FCAW，which could meet the requirements of national standard Code for Welding of Steel Structures GB506612011． The WPS provided the beneficial reference for the future engineering application and the development of relevant standards．
2014, 44(03): 33-38.
doi: 10.13204/j.gyjz201403009
Abstract:
According to the experimental data of high-strength angles capacity (Q460) of the unilateral connection and the results of numerical analysis by using ANSYS，the practical formula of the unilateral connection of the ratio of width to thickness for Q460 high-strength angle was derived，and the practical formula of the unilateral connection and restrained torsion of the capacity for high-strength angle was derived also． At the same time，using the related experimental data to validate the exactitude of these practical formulas，which provide a guide for the design of unilateral connection bar of the high-strength angle．
According to the experimental data of high-strength angles capacity (Q460) of the unilateral connection and the results of numerical analysis by using ANSYS，the practical formula of the unilateral connection of the ratio of width to thickness for Q460 high-strength angle was derived，and the practical formula of the unilateral connection and restrained torsion of the capacity for high-strength angle was derived also． At the same time，using the related experimental data to validate the exactitude of these practical formulas，which provide a guide for the design of unilateral connection bar of the high-strength angle．
2014, 44(03): 39-42.
doi: 10.13204/j.gyjz201403010
Abstract:
This paper presents a new type high-strength steel-concrete composite flat beam，its mechanical behavior is compared with the traditional composite flat beam，and the impact of steel strength on the new type composite flat beam is analyzed by using the large finite element software ABAQUS． The analysis shows that as compared with the traditional composite flat beams，the mechanical behavior of the new type composite flat beam is more superior． Under the same condition of sectional height and steel consumption，the load bearing capacity of new type composite flat beam is increased by 9. 7 percent，the stiffness increased by 0. 88 percent． The strength of steel has greater influence on the load bearing capacity than the stiffness of new type composite flat beam．
This paper presents a new type high-strength steel-concrete composite flat beam，its mechanical behavior is compared with the traditional composite flat beam，and the impact of steel strength on the new type composite flat beam is analyzed by using the large finite element software ABAQUS． The analysis shows that as compared with the traditional composite flat beams，the mechanical behavior of the new type composite flat beam is more superior． Under the same condition of sectional height and steel consumption，the load bearing capacity of new type composite flat beam is increased by 9. 7 percent，the stiffness increased by 0. 88 percent． The strength of steel has greater influence on the load bearing capacity than the stiffness of new type composite flat beam．
2014, 44(03): 43-47.
doi: 10.13204/j.gyjz201403011
Abstract:
To promote more rapid development and application of high strength steel in China，the material was applied in Greenland Central Plaza in Zhengzhou． The material strength and design parameters were studied，and the buildings structural key indexes before and after the application of the high strength steel are analyzed． The study shows that when the high strength steel is applied in a high-rise building 20% steel can be saved without any influence to the structure response． The application of high strength steel in civil buildings should be promoted．
To promote more rapid development and application of high strength steel in China，the material was applied in Greenland Central Plaza in Zhengzhou． The material strength and design parameters were studied，and the buildings structural key indexes before and after the application of the high strength steel are analyzed． The study shows that when the high strength steel is applied in a high-rise building 20% steel can be saved without any influence to the structure response． The application of high strength steel in civil buildings should be promoted．
2014, 44(03): 48-51.
doi: 10.13204/j.gyjz201403012
Abstract:
Tianjin West-Station，located in Tianjin centre urban area，is one of the important stations for Beijing- Shanghai high-speed rail way; a seamless butt-joint will be realized for high-speed railway，subway，city bus and other modes of transportation after its completion; which is a typical modernized large-scale comprehensive transport hub． Taking the south plaza urban design of Tianjin West Station for example，from the function，image of gateway space，three-dimensional transport and composite space and culture continuation，it was introduced the urban design method of large-scale comprehensive transport hub in the city center． Through practice and exploration，it is to be achieved the changes from the simple traffic control center square to the multi-functional public space，thus driving the regional functions and upgrading the overall image of the city．
Tianjin West-Station，located in Tianjin centre urban area，is one of the important stations for Beijing- Shanghai high-speed rail way; a seamless butt-joint will be realized for high-speed railway，subway，city bus and other modes of transportation after its completion; which is a typical modernized large-scale comprehensive transport hub． Taking the south plaza urban design of Tianjin West Station for example，from the function，image of gateway space，three-dimensional transport and composite space and culture continuation，it was introduced the urban design method of large-scale comprehensive transport hub in the city center． Through practice and exploration，it is to be achieved the changes from the simple traffic control center square to the multi-functional public space，thus driving the regional functions and upgrading the overall image of the city．
2014, 44(03): 52-54.
doi: 10.13204/j.gyjz201403013
Abstract:
The protecting of the industrial heritage holds an important position in todays urban planning and construction． It needs to focus on the overall context of a city，but also much attention should be paid to the re-use and sustainable development． This thesis focuses on re-use research and protection analysis of industrial heritage of Wuxi Xizhang Silkworm Farm． To maximize the preservation of part of the buildings history traces in the farm，and to seek coherence and permeability between each building the formation of a unified space． By means of recovering and expanding the scale of mulberry and blend with the landscape，a unified body can be formed． Finally solve it will the solved the decline problem of the industrial history architecture and landscape of silkworm field． By means of combining the industrial heritage development with education and tourism development，it will be identified problems of industrial historical building survival itself and found out countermeasures for sustainable development．
The protecting of the industrial heritage holds an important position in todays urban planning and construction． It needs to focus on the overall context of a city，but also much attention should be paid to the re-use and sustainable development． This thesis focuses on re-use research and protection analysis of industrial heritage of Wuxi Xizhang Silkworm Farm． To maximize the preservation of part of the buildings history traces in the farm，and to seek coherence and permeability between each building the formation of a unified space． By means of recovering and expanding the scale of mulberry and blend with the landscape，a unified body can be formed． Finally solve it will the solved the decline problem of the industrial history architecture and landscape of silkworm field． By means of combining the industrial heritage development with education and tourism development，it will be identified problems of industrial historical building survival itself and found out countermeasures for sustainable development．
2014, 44(03): 55-59.
doi: 10.13204/j.gyjz201403014
Abstract:
The structure of compounded raw soil wall is a ecological，energy-saving and assembled monolithic structure，which is a new system for village residential building． Based on previous research achievements and experiment results，it was analyzed the failure process and force characteristics of composite-wall structure with mud blocks under vertical and horizontal loads． The comparative analysis was done for the damage characteristics of the compounded raw soil wall and the standard wall with aerated concrete blocks，it was also discussed the wall bearing capacity，ductility，energy dissipation and seismic performance． On the basis of this，the calculating model and seismic tectonic measure of composite-wall structure with mud blocks were proposed． Test research and pilot project show that the structure of compounded raw soil wall with mud blocks is a structure with good seismic behaviour． At the same time，the structure has the characteristics of using local materials，simple production，energy efficiency and environmental protection． It is suitable for low-rise village and town buildings．
The structure of compounded raw soil wall is a ecological，energy-saving and assembled monolithic structure，which is a new system for village residential building． Based on previous research achievements and experiment results，it was analyzed the failure process and force characteristics of composite-wall structure with mud blocks under vertical and horizontal loads． The comparative analysis was done for the damage characteristics of the compounded raw soil wall and the standard wall with aerated concrete blocks，it was also discussed the wall bearing capacity，ductility，energy dissipation and seismic performance． On the basis of this，the calculating model and seismic tectonic measure of composite-wall structure with mud blocks were proposed． Test research and pilot project show that the structure of compounded raw soil wall with mud blocks is a structure with good seismic behaviour． At the same time，the structure has the characteristics of using local materials，simple production，energy efficiency and environmental protection． It is suitable for low-rise village and town buildings．
2014, 44(03): 60-67.
doi: 10.13204/j.gyjz201403015
Abstract:
Combined with mechanical characteristics of open-hole eco-composite wall in horizontal and vertical loads and based on the shear resistance mechanism theory，the holed walls shear resistance mechanism system in simit state was set up． Through the numerical analysis of extension，inclined section shear bearing capacity calculation formula of the open-hole wall was deduced，and determined the reasonable value of the holed wall oblique compression bar effective strength coefficient． Test research，theoretical analysis and numerical simulation show that the proposed holed eco-composite wall inclined section shear bearing capacity calculation formula has the certain theory basis and practical value，which can meet the need of actual engineering calculation．
Combined with mechanical characteristics of open-hole eco-composite wall in horizontal and vertical loads and based on the shear resistance mechanism theory，the holed walls shear resistance mechanism system in simit state was set up． Through the numerical analysis of extension，inclined section shear bearing capacity calculation formula of the open-hole wall was deduced，and determined the reasonable value of the holed wall oblique compression bar effective strength coefficient． Test research，theoretical analysis and numerical simulation show that the proposed holed eco-composite wall inclined section shear bearing capacity calculation formula has the certain theory basis and practical value，which can meet the need of actual engineering calculation．
2014, 44(03): 68-73.
doi: 10.13204/j.gyjz201403016
Abstract:
By the study on the test of 1 /2 scale fundamental element of ecological composite wall，it was compared different factors of bearing capacity and failure mode of fundamentdal element． Then the reasonable failure modes of the fundamental element were proposed． A nonlinear finite element model was set up and relative stiffness and relative strength of the fundamental element were analyzed based on the reasonable failure modes on the basis of the test results and numerical analysis． The study on the test and the analysis show that the reasonable failure modes of fundamental element are the corner crush of block ( CC failure modes)． In order to make the CC failure modes occurred，the reasonable value of the relative stiffness of fundamental element is 2. 14 h 3. 47，and the reasonable value of the relative strength fundamental element is 4. 66nc8. 04．
By the study on the test of 1 /2 scale fundamental element of ecological composite wall，it was compared different factors of bearing capacity and failure mode of fundamentdal element． Then the reasonable failure modes of the fundamental element were proposed． A nonlinear finite element model was set up and relative stiffness and relative strength of the fundamental element were analyzed based on the reasonable failure modes on the basis of the test results and numerical analysis． The study on the test and the analysis show that the reasonable failure modes of fundamental element are the corner crush of block ( CC failure modes)． In order to make the CC failure modes occurred，the reasonable value of the relative stiffness of fundamental element is 2. 14 h 3. 47，and the reasonable value of the relative strength fundamental element is 4. 66nc8. 04．
2014, 44(03): 74-79.
doi: 10.13204/j.gyjz201403017
Abstract:
Various choices of fill material within the ecological complexes of the wall structure became a problem that needs solution． It was presented that the preparing process，uniaxial compression constitutive model merits and demerits of several new types of building malerials，which are more widely used at home and abroad． Comparing analysis of the stress-strain relation of several ecological blocks was done． Finally the twin shear unified strength theory was used to derive multi-axial elastic-plastic constitutive relation，and a numerical simulation of comparative analysis was also done for composite wall filled with different materials by ABAQUS to draw their scope of ecological composite wall structure system． Studies have shown that:ceramic blocks can be used in middle-high rise buildings; aerated blocks and foam blocks can be used in multi-storey buildings; grass tiles can be used in low-rise buildings; while the plaster，due to its poor ductility and durability，is not recommended for the structural system．
Various choices of fill material within the ecological complexes of the wall structure became a problem that needs solution． It was presented that the preparing process，uniaxial compression constitutive model merits and demerits of several new types of building malerials，which are more widely used at home and abroad． Comparing analysis of the stress-strain relation of several ecological blocks was done． Finally the twin shear unified strength theory was used to derive multi-axial elastic-plastic constitutive relation，and a numerical simulation of comparative analysis was also done for composite wall filled with different materials by ABAQUS to draw their scope of ecological composite wall structure system． Studies have shown that:ceramic blocks can be used in middle-high rise buildings; aerated blocks and foam blocks can be used in multi-storey buildings; grass tiles can be used in low-rise buildings; while the plaster，due to its poor ductility and durability，is not recommended for the structural system．
2014, 44(03): 80-84.
doi: 10.13204/j.gyjz201403018
Abstract:
The strength and stability analysis of super large cooling tower with gas flue are calculated by finite element method． The research shows that stress concentration nearby the open hole is very distinct，and the safe factor of stability near holes is much less than the value without holes; Local stability of tower in the area of holes controls the design of such kind of cooling towers． The corresponding reinforcement schemes for cooling tower with gas flue are proposed lastly，and reinforcement effect of each scheme is compared for selecting the better one．
The strength and stability analysis of super large cooling tower with gas flue are calculated by finite element method． The research shows that stress concentration nearby the open hole is very distinct，and the safe factor of stability near holes is much less than the value without holes; Local stability of tower in the area of holes controls the design of such kind of cooling towers． The corresponding reinforcement schemes for cooling tower with gas flue are proposed lastly，and reinforcement effect of each scheme is compared for selecting the better one．
2014, 44(03): 85-90.
doi: 10.13204/j.gyjz201403019
Abstract:
The cumulative pore pressure dissipation of saturated clay is an important factor in the settlement of roadbed under traffic load． According to the characteristics of making the hollow cylindrical specimens of saturated clay，it was introduced the fabrication process of saturated clay hollow cylindrical specimen in detail． The specimens were consolidated under 100 kPa，150 kPa，and 200 kPa，then，the undrained cyclic loading test was done with the change in the principal stress axis rotation continuous range being ［－ 15，15］，［－ 30，30］，［－ 45，45］，and ［－ 60，60］，therefore，the effect rules that were confining pressure，the principal stress axis rotation angle and the static deviator stress respectively on the cycle cumulative pore pressure were obtained． Using the modified dynamic deviator stress level to consider the effect of initial static deviator stress and dynamic deviator stress on the undrained cumulative pore pressure，the cumulative pore pressure model of constant shear stress cycle deviation angle of principal stress axis under cyclic loading was established． Through the cumulative pore pressure value of non-isotropic consolidation cyclic torsional shear test，the correctness of the established cumulative pore pressure model was verified．
The cumulative pore pressure dissipation of saturated clay is an important factor in the settlement of roadbed under traffic load． According to the characteristics of making the hollow cylindrical specimens of saturated clay，it was introduced the fabrication process of saturated clay hollow cylindrical specimen in detail． The specimens were consolidated under 100 kPa，150 kPa，and 200 kPa，then，the undrained cyclic loading test was done with the change in the principal stress axis rotation continuous range being ［－ 15，15］，［－ 30，30］，［－ 45，45］，and ［－ 60，60］，therefore，the effect rules that were confining pressure，the principal stress axis rotation angle and the static deviator stress respectively on the cycle cumulative pore pressure were obtained． Using the modified dynamic deviator stress level to consider the effect of initial static deviator stress and dynamic deviator stress on the undrained cumulative pore pressure，the cumulative pore pressure model of constant shear stress cycle deviation angle of principal stress axis under cyclic loading was established． Through the cumulative pore pressure value of non-isotropic consolidation cyclic torsional shear test，the correctness of the established cumulative pore pressure model was verified．
2014, 44(03): 91-96.
doi: 10.13204/j.gyjz201403020
Abstract:
The microstructure of contaminated remolded clay was observed using scanning electron microscopy (SEM) after the preparation for the clay contaminated by sodium carbonate (Na2CO3 ) of different concentrations through immersion test． Subsequently，the apparent porosity and pore size distribution of the contaminated remolded clay were extracted by Matlab． Furthermore，the microstructure transformation mechanism of the contaminated remolded clay was investigated． The studies showed that the microstructure of the clay was transformed such as the destruction of flocculent structure，the redistribution of particles and pore，as well as the obvious reduction of pore porosity owing to the contamination and erosion of Na2CO3 ． Based on manual selection of the best threshold level，the apparent porosity of contaminated remolded clay extracted by Matlab was significantly decreased with the increase of Na2CO3 erosion degree． Meanwhile，the apparent pore size distribution was characterized by the gradual evolution from a majority of macro and meso pores to minor and micro ones． Finally，the transformation of the clay microstructure maybe caused by the diverse effects of Na2CO3 : the ion exchange and adsorption with clay particles， the chemical reaction with non-alkali metal cations and free oxide，as well as the neutralization with humic acid．
The microstructure of contaminated remolded clay was observed using scanning electron microscopy (SEM) after the preparation for the clay contaminated by sodium carbonate (Na2CO3 ) of different concentrations through immersion test． Subsequently，the apparent porosity and pore size distribution of the contaminated remolded clay were extracted by Matlab． Furthermore，the microstructure transformation mechanism of the contaminated remolded clay was investigated． The studies showed that the microstructure of the clay was transformed such as the destruction of flocculent structure，the redistribution of particles and pore，as well as the obvious reduction of pore porosity owing to the contamination and erosion of Na2CO3 ． Based on manual selection of the best threshold level，the apparent porosity of contaminated remolded clay extracted by Matlab was significantly decreased with the increase of Na2CO3 erosion degree． Meanwhile，the apparent pore size distribution was characterized by the gradual evolution from a majority of macro and meso pores to minor and micro ones． Finally，the transformation of the clay microstructure maybe caused by the diverse effects of Na2CO3 : the ion exchange and adsorption with clay particles， the chemical reaction with non-alkali metal cations and free oxide，as well as the neutralization with humic acid．
RESEARCH ON PROPERTIES OF DEFORMATION AND MECHANICS ON DOUBLE-ROW PILE STRUCTURE WITH FLAKE TOP BEAM
2014, 44(03): 97-103.
doi: 10.13204/j.gyjz201403021
Abstract:
The 3D FEM software MIDAS-GTS was used for establishing numerical analysis model of double-row pile structure with flake top beam，in which practical soil layers，solid supporting structures，Goodman contact elements and actual construction stages were simulatneously considered． The resulted of the study showed that the horizontal displacement of supporting pile was strongly limited by flake top beam when the size of deep excavation was not large enough． The maximum values of bending moment and shearing force of top beam always appeared near the corner of the excavation． Along with change of the length of top beam，while other parameters were fixed，the curves of horizontal displacement and shear force of top beam were just single variable function with only one argument (horizontal displacement from the corner of the excavation)，which little related with the length of top beam． When the hight of top beam was raised，the bending moment and shearing force of top beam were highly increased but the decrease of horizontal displacement of top beam was not sharp． Along with increasing of the depth of the excavation， the value of bending moment and internal force in the middle of top beam rose obviously． While the distance between the front and back pile increased，the value of bending moment and internal force in the middle of top beam decreased，yet，the rate of reduction also decreased． The increment of the distance between the front and back pile impacted the bending moment and internal force of top beam slightly．
The 3D FEM software MIDAS-GTS was used for establishing numerical analysis model of double-row pile structure with flake top beam，in which practical soil layers，solid supporting structures，Goodman contact elements and actual construction stages were simulatneously considered． The resulted of the study showed that the horizontal displacement of supporting pile was strongly limited by flake top beam when the size of deep excavation was not large enough． The maximum values of bending moment and shearing force of top beam always appeared near the corner of the excavation． Along with change of the length of top beam，while other parameters were fixed，the curves of horizontal displacement and shear force of top beam were just single variable function with only one argument (horizontal displacement from the corner of the excavation)，which little related with the length of top beam． When the hight of top beam was raised，the bending moment and shearing force of top beam were highly increased but the decrease of horizontal displacement of top beam was not sharp． Along with increasing of the depth of the excavation， the value of bending moment and internal force in the middle of top beam rose obviously． While the distance between the front and back pile increased，the value of bending moment and internal force in the middle of top beam decreased，yet，the rate of reduction also decreased． The increment of the distance between the front and back pile impacted the bending moment and internal force of top beam slightly．
2014, 44(03): 104-109.
doi: 10.13204/j.gyjz201403022
Abstract:
Aiming at the creep deformation problem of asphalt pavement under different temperature conditions， taking Burgers model as the theoretical basis，using the data analysis software Origin 8. 1 a fitting analysis of different temperature creep test curves was done to get the four creep equation parameters of Burgers model，and the Burgers creep equation was changed into Prony series by Laplace transform and inverse Laplace transform． Through these processes，the relative relaxation moduli g1 ，g2 and relaxation time 1 ，2 were got，which were associated with temperature of asphalt mixture． The distribution of creep deformation of asphalt pavement under the different temperature and loaded time conditions were analyzed by 3D FEM． The results show that under different temperature conditions the lateral extent of creep deformation at pavement surface is 0. 88 m，and the scope of deformation extending to the outside wheel track is wider than that of the inside． The higher the temperature，the greater the strain of pavement surface，strain mutation will appear on the surface at 60 ℃． When the pavement withstands 5. 4 106 total number of equivalent standard axle load，1 cm rut will be produced，which raises a higher requirement for high temperature stability of asphalt pavement．
Aiming at the creep deformation problem of asphalt pavement under different temperature conditions， taking Burgers model as the theoretical basis，using the data analysis software Origin 8. 1 a fitting analysis of different temperature creep test curves was done to get the four creep equation parameters of Burgers model，and the Burgers creep equation was changed into Prony series by Laplace transform and inverse Laplace transform． Through these processes，the relative relaxation moduli g1 ，g2 and relaxation time 1 ，2 were got，which were associated with temperature of asphalt mixture． The distribution of creep deformation of asphalt pavement under the different temperature and loaded time conditions were analyzed by 3D FEM． The results show that under different temperature conditions the lateral extent of creep deformation at pavement surface is 0. 88 m，and the scope of deformation extending to the outside wheel track is wider than that of the inside． The higher the temperature，the greater the strain of pavement surface，strain mutation will appear on the surface at 60 ℃． When the pavement withstands 5. 4 106 total number of equivalent standard axle load，1 cm rut will be produced，which raises a higher requirement for high temperature stability of asphalt pavement．
2014, 44(03): 110-113.
doi: 10.13204/j.gyjz201403023
Abstract:
In order to research internal damage and supersonic wave characteristic of early-age high strength concrete subjected to repeated load，cubic concrete samples were made in laboratory，demoulded and maintained in standard curing room． Cubic concrete samples were repeatedly compressed with their 50%，70% and 80% ultimate load at 1d，2d and 3d age respectively． Uniaxial compressive strength and supersonic wave velocity were recorded to be used to analyze the variation law of the samples before and after loading． The wave velocities of 7 d，14 d and 28 d cubic concrete samples were measured，and then compressed to crush． The results show that supersonic wave velocity increases with concrete age infirst 28 days，and has linear relationship with strength． Damage and variation law are different for the first 3 d age concrete samples subjected to different proportion ultimate load，which can be observed by uniaxial compressive strength and supersonic wave velocity． It is helpful to evaluate the accumulated damage law of early-age high strength concrete subjected to repeated blasting load in a blast project．
In order to research internal damage and supersonic wave characteristic of early-age high strength concrete subjected to repeated load，cubic concrete samples were made in laboratory，demoulded and maintained in standard curing room． Cubic concrete samples were repeatedly compressed with their 50%，70% and 80% ultimate load at 1d，2d and 3d age respectively． Uniaxial compressive strength and supersonic wave velocity were recorded to be used to analyze the variation law of the samples before and after loading． The wave velocities of 7 d，14 d and 28 d cubic concrete samples were measured，and then compressed to crush． The results show that supersonic wave velocity increases with concrete age infirst 28 days，and has linear relationship with strength． Damage and variation law are different for the first 3 d age concrete samples subjected to different proportion ultimate load，which can be observed by uniaxial compressive strength and supersonic wave velocity． It is helpful to evaluate the accumulated damage law of early-age high strength concrete subjected to repeated blasting load in a blast project．
2014, 44(03): 114-118.
doi: 10.13204/j.gyjz201403024
Abstract:
The paper takes the fundamental nature of gangue aggregates，such as the type of coal gangues，the particle size grading and aggregate pretreatment as studied objects，the compressive strength and elastic modulus of gangue concrete with different curing periods(7d、28d、90d) are observed，its results can provide the basis for the mix design optimization of gangue concrete． Results of the trial indicate that the gangue itself strength greatly affected its concrete strength，and the gangue concrete could achieve the maximum strength under the condition of coal ganguecement matrix strength being harmonious with the cement matrix strength; in the low-strength cement matrix， improving the aggregates particle size and occupancy ratio could not improve its concrete strength; the pretreatment of spontaneous combustion gangue can improve the concrete strength，but the non-spontaneous combustion gangue is different．
The paper takes the fundamental nature of gangue aggregates，such as the type of coal gangues，the particle size grading and aggregate pretreatment as studied objects，the compressive strength and elastic modulus of gangue concrete with different curing periods(7d、28d、90d) are observed，its results can provide the basis for the mix design optimization of gangue concrete． Results of the trial indicate that the gangue itself strength greatly affected its concrete strength，and the gangue concrete could achieve the maximum strength under the condition of coal ganguecement matrix strength being harmonious with the cement matrix strength; in the low-strength cement matrix， improving the aggregates particle size and occupancy ratio could not improve its concrete strength; the pretreatment of spontaneous combustion gangue can improve the concrete strength，but the non-spontaneous combustion gangue is different．
2014, 44(03): 119-122.
doi: 10.13204/j.gyjz201403025
Abstract:
The experimental research on the compressive strength，split tensile strength，shear strength and flexure behaviours of straight steel fiber and indented steel fiber reinforced lightweight aggregate concrete ( SFRLAC) was conducted respectively． The mixing amount of steel fiber ranged from 0 to 120 kg /m3 ． The results show that the adding of steel fiber into the matrix leads to a little enhancement on compressive strength，while remarkable enhancement on the split tensile strength，shear strength and flexure behaviours． There are almost no difference between enhancing effect on the SFRLAC compressive strength of the straight steel fiber and that of indented steel fiber at the same mixing amount． The indented steel fiber leads the more obvious enhancement on the split tensile strength，shear strength and flexure behaviours of SFRLAC． On the section of bending failure specimen，the steel fibers were pulled out，not broken，and the ceramisite were broken，not destroyed from the interface debonding with the ceramisite． The advice of suitably increasing the tensile strength of ceramisite and decreasing the tensile strength of steel fiber is put forward to increase the performance price ratio of the SFRLAC．
The experimental research on the compressive strength，split tensile strength，shear strength and flexure behaviours of straight steel fiber and indented steel fiber reinforced lightweight aggregate concrete ( SFRLAC) was conducted respectively． The mixing amount of steel fiber ranged from 0 to 120 kg /m3 ． The results show that the adding of steel fiber into the matrix leads to a little enhancement on compressive strength，while remarkable enhancement on the split tensile strength，shear strength and flexure behaviours． There are almost no difference between enhancing effect on the SFRLAC compressive strength of the straight steel fiber and that of indented steel fiber at the same mixing amount． The indented steel fiber leads the more obvious enhancement on the split tensile strength，shear strength and flexure behaviours of SFRLAC． On the section of bending failure specimen，the steel fibers were pulled out，not broken，and the ceramisite were broken，not destroyed from the interface debonding with the ceramisite． The advice of suitably increasing the tensile strength of ceramisite and decreasing the tensile strength of steel fiber is put forward to increase the performance price ratio of the SFRLAC．
2014, 44(03): 123-128.
doi: 10.13204/j.gyjz201403026
Abstract:
It was carried out inspection of displacement and deformation of shear walls for a high-rise house during construction period，compared and analyzed difference of internal forces of shear wall before and after displacement and deformation，also analyzed influence to main structure and members caused by displacement and deformation of shear wall． The calculation results show that before and after the displacement and deformation of shear walls， integrated differences of various internal forces within plane are small，while that out of plane are relatively big． Generally，after displacement and deformation of shear walls，all the internal forces out of plane are increased to different extents． However，the absolute value of increased forces is relatively small although the extents of internal forces are big in members with large displacement and deformation． After displacement and deformation of shear wall members，the loading capacity of structure and members complies with requirements of codes and standards，under influence of internal forces within and out of planes．
It was carried out inspection of displacement and deformation of shear walls for a high-rise house during construction period，compared and analyzed difference of internal forces of shear wall before and after displacement and deformation，also analyzed influence to main structure and members caused by displacement and deformation of shear wall． The calculation results show that before and after the displacement and deformation of shear walls， integrated differences of various internal forces within plane are small，while that out of plane are relatively big． Generally，after displacement and deformation of shear walls，all the internal forces out of plane are increased to different extents． However，the absolute value of increased forces is relatively small although the extents of internal forces are big in members with large displacement and deformation． After displacement and deformation of shear wall members，the loading capacity of structure and members complies with requirements of codes and standards，under influence of internal forces within and out of planes．
2014, 44(03): 129-133.
doi: 10.13204/j.gyjz201403027
Abstract:
Combining with Guangxi Xiejiadong cave tunnel hydrogeology as well as the collapse of the karst cave in tunnel construction，it was introduces the tunnel karst caveback fill excavation methodconstruction technique． Through the implementation of this technology，it had been effectively solved the problem of the unstable rock mass collapse，which explored a path for the construction of the large water-eroded cave tunnel．
Combining with Guangxi Xiejiadong cave tunnel hydrogeology as well as the collapse of the karst cave in tunnel construction，it was introduces the tunnel karst caveback fill excavation methodconstruction technique． Through the implementation of this technology，it had been effectively solved the problem of the unstable rock mass collapse，which explored a path for the construction of the large water-eroded cave tunnel．
2014, 44(03): 134-146.
doi: 10.13204/j.gyjz201403028
Abstract:
Steel reinforced concrete ( SRC) irregular section columns structure can not only make better use of available space and improve the esthetic appearance of structure，but also overcome the weakness of reinforced concrete structure，such as bearing capacity is insufficient and seismic performance is poor． Therefore it has important significance to promote the use of irregular section column structure． Based on the introduction of research background of SRC irregular section column structure，this paper summarizes the research status in the following field as axial compression performance，eccentric compression performance，shear performance and seismic performance of SRC irregular section column，shear performance and seismic performance of joint in the SRC frame with irregular section columns，seismic performance of SRC frame with irregular section columns and construction requirement． Also，the problems which have not been solved are pointed out． This work can provide references for the intensive research and application of SRC irregular section column structure．
Steel reinforced concrete ( SRC) irregular section columns structure can not only make better use of available space and improve the esthetic appearance of structure，but also overcome the weakness of reinforced concrete structure，such as bearing capacity is insufficient and seismic performance is poor． Therefore it has important significance to promote the use of irregular section column structure． Based on the introduction of research background of SRC irregular section column structure，this paper summarizes the research status in the following field as axial compression performance，eccentric compression performance，shear performance and seismic performance of SRC irregular section column，shear performance and seismic performance of joint in the SRC frame with irregular section columns，seismic performance of SRC frame with irregular section columns and construction requirement． Also，the problems which have not been solved are pointed out． This work can provide references for the intensive research and application of SRC irregular section column structure．
2014, 44(03): 147-149.
doi: 10.13204/j.gyjz201403029
Abstract:
The beam-column semi-rigid joint becomes more and more widely applied recently in the engineering practice due to various advantages． But the study on the mechanical properties of the joint is far from perfect in China． In the paper，four sets of specimens of the beam-column semi-rigid joint of the concrete-filled square tube were made． The study and description of mechanical behavior and failure mode of the joint under the low cycle cyclic loads were also done． It is concluded that the joint has good ductility and the capability of energy dissipation by the analysis of the various indicators． The study provides some reference for the node design of steel structure．
The beam-column semi-rigid joint becomes more and more widely applied recently in the engineering practice due to various advantages． But the study on the mechanical properties of the joint is far from perfect in China． In the paper，four sets of specimens of the beam-column semi-rigid joint of the concrete-filled square tube were made． The study and description of mechanical behavior and failure mode of the joint under the low cycle cyclic loads were also done． It is concluded that the joint has good ductility and the capability of energy dissipation by the analysis of the various indicators． The study provides some reference for the node design of steel structure．
2014, 44(03): 150-157.
doi: 10.13204/j.gyjz201403030
Abstract:
A new type of prestressed steel box-concrete composite beam is proposed，whose advantages and applicability were analysed，the formula of ultimate capacity and the fiber model method of the structure were researched as well． Through the theoretical calculation and experiment analysis of the ultimate bearing capacity of the beam，furthermore，it was compared the beams of 3 different spans with other types of beams，the influential parameters on the ultimate capacity such as the thickness of steel sheet，the grade of concrete，the number of steel strand，the location of separator etc． were researched，which demonstrate that the longer the span，the advantage of this composite beam in ultimate capacity and deflection． As a result，it was suggested that the proposed prestressed steel box-concrete composite beam should be used in the house and bridge structure whose span is longer than 12 m．
A new type of prestressed steel box-concrete composite beam is proposed，whose advantages and applicability were analysed，the formula of ultimate capacity and the fiber model method of the structure were researched as well． Through the theoretical calculation and experiment analysis of the ultimate bearing capacity of the beam，furthermore，it was compared the beams of 3 different spans with other types of beams，the influential parameters on the ultimate capacity such as the thickness of steel sheet，the grade of concrete，the number of steel strand，the location of separator etc． were researched，which demonstrate that the longer the span，the advantage of this composite beam in ultimate capacity and deflection． As a result，it was suggested that the proposed prestressed steel box-concrete composite beam should be used in the house and bridge structure whose span is longer than 12 m．
2014, 44(03): 158-161.
doi: 10.13204/j.gyjz201403031
Abstract:
The order of the Phoenix International Media Center Mobius ring shape wall by a plurality of different sizes of the face curtain wall，through scale-like organization，to form a continuous surface． Wall unit for each connection point plate deformation angle characteristics are not the same size，the design uses aluminum clad steel keel dustpan unitized curtain wall construction method，cell plate steel hoop ear plate fixed at its anchor point for the hoop screw center points，steel hoop in a horizontal plane through the deputy bearing left and right adjustment 25 mm， bearings and through the threaded stud between the upper and lower adjustable 30 mm，processing and installation of curtain wall to ensure accuracy，quality，and meet the deformation control requirements．
The order of the Phoenix International Media Center Mobius ring shape wall by a plurality of different sizes of the face curtain wall，through scale-like organization，to form a continuous surface． Wall unit for each connection point plate deformation angle characteristics are not the same size，the design uses aluminum clad steel keel dustpan unitized curtain wall construction method，cell plate steel hoop ear plate fixed at its anchor point for the hoop screw center points，steel hoop in a horizontal plane through the deputy bearing left and right adjustment 25 mm， bearings and through the threaded stud between the upper and lower adjustable 30 mm，processing and installation of curtain wall to ensure accuracy，quality，and meet the deformation control requirements．
2014, 44(03): 162-168.
doi: 10.13204/j.gyjz201403032
Abstract:
This paper compared the stability factors of beams in various international codes for design of steel structures，and corresponding load factors． The results of reliability analyses specified by AISC code and EC3 are also introduced． The main conclusions are as below: 1) Stability factors from large to small in codes are Canada，AISC and China and Japan; 2) except the Chinese code，the stability factors tend to be average of test results if their live load factors are also greater; 3) the reliability index analysis of steel beam specified by AISC reveals that its safety index is less than required，especially when the live load is predominant; 4) GB 500172003 has relatively large stability factors but the smallest live load factors，implying the least safety index．
This paper compared the stability factors of beams in various international codes for design of steel structures，and corresponding load factors． The results of reliability analyses specified by AISC code and EC3 are also introduced． The main conclusions are as below: 1) Stability factors from large to small in codes are Canada，AISC and China and Japan; 2) except the Chinese code，the stability factors tend to be average of test results if their live load factors are also greater; 3) the reliability index analysis of steel beam specified by AISC reveals that its safety index is less than required，especially when the live load is predominant; 4) GB 500172003 has relatively large stability factors but the smallest live load factors，implying the least safety index．
2014, 44(03): 169-172.
doi: 10.13204/j.gyjz201403033
Abstract:
A 3-story frame structure was put into operation in 2002 and was on fire in september 2012，because the short-circuit of aged wire belong to the car wash located in the underground parking． The main burned area was about 180 m2 during the 2. 5 h． Above the burned area is the roof parking ramp-way of the large supermarket． In order to assure the safety of the whole structure，the reinforced concrete beam，column and slab after fire were test on-site and the structure was checking-calculated through the PKPM software by the presumption strength． According to comparison of the reinforced methods and analysis of the checking calculated results，the enlargement section， embedded steel bars and grouting materials perfusion were adopted to strengthen the frame structure． There is no cracks and deformation in the structure until now． Which shows that the reinforced mode is reasonable and the enhancement effect is good．
A 3-story frame structure was put into operation in 2002 and was on fire in september 2012，because the short-circuit of aged wire belong to the car wash located in the underground parking． The main burned area was about 180 m2 during the 2. 5 h． Above the burned area is the roof parking ramp-way of the large supermarket． In order to assure the safety of the whole structure，the reinforced concrete beam，column and slab after fire were test on-site and the structure was checking-calculated through the PKPM software by the presumption strength． According to comparison of the reinforced methods and analysis of the checking calculated results，the enlargement section， embedded steel bars and grouting materials perfusion were adopted to strengthen the frame structure． There is no cracks and deformation in the structure until now． Which shows that the reinforced mode is reasonable and the enhancement effect is good．
2014, 44(03): 173-176.
doi: 10.13204/j.gyjz201403034
Abstract:
There is a serious collapse in a mine vertical shaft of a cement factory which can not be used． After synthesis analysis and numerical simulation of 2D finite element，the repair and reinforcement scheme，that the template + steel reinforced concrete lining (internal model method) + bolt (soil nailing block method) + Mn steel casing ( casing follow-up method) is confirmed． The plan have already been carried out，and its feasibility is verified． It is a successful case of mine vertical shaft repair and reinforcement．
There is a serious collapse in a mine vertical shaft of a cement factory which can not be used． After synthesis analysis and numerical simulation of 2D finite element，the repair and reinforcement scheme，that the template + steel reinforced concrete lining (internal model method) + bolt (soil nailing block method) + Mn steel casing ( casing follow-up method) is confirmed． The plan have already been carried out，and its feasibility is verified． It is a successful case of mine vertical shaft repair and reinforcement．
2014, 44(03): 177-179.
doi: 10.13204/j.gyjz201403035
Abstract:
In the development of city，it is a real challenge that how to deal with the old buildings． Too many old buildings are disappearing in the rapid development of China． Based on the analysis of the design award cases， various means in passive technologies that can be used for old building renovation were summarized． Through the simulation，it was found that for the old buildings with large length，the changing of the overall layout can improve the natural ventilation efficiently and the shading ability． Furthermore，the green technology of the exterior structure can improve the buildings shading and lower indoor temperature in summer．
In the development of city，it is a real challenge that how to deal with the old buildings． Too many old buildings are disappearing in the rapid development of China． Based on the analysis of the design award cases， various means in passive technologies that can be used for old building renovation were summarized． Through the simulation，it was found that for the old buildings with large length，the changing of the overall layout can improve the natural ventilation efficiently and the shading ability． Furthermore，the green technology of the exterior structure can improve the buildings shading and lower indoor temperature in summer．
2014, 44(03): 180-183.
doi: 10.13204/j.gyjz201403036
Abstract:
Sheffield，UK as earlier experienced urban decay and urban renewal in the city，by fully exploring the industrial heritage of the intangible and tangible value to it as to enhance the basic concept of the urban culture，thus promoting urban renewal and economic development． It was studied the tools and features of the citys industrial heritage protection and development practice． It was explored specifically the protective practice based on the fusion way from the old space to promote adaptive re-use，shaping the image of cultural and eco-industrial cultural landscape，realizing the direction of the transformation of sustainable cultural and creative industries，as well as implementing the multi-level policy actions of the government regulatory agencies． This mode provided a reference for protection，development and utilization of industrial heritages in China．
Sheffield，UK as earlier experienced urban decay and urban renewal in the city，by fully exploring the industrial heritage of the intangible and tangible value to it as to enhance the basic concept of the urban culture，thus promoting urban renewal and economic development． It was studied the tools and features of the citys industrial heritage protection and development practice． It was explored specifically the protective practice based on the fusion way from the old space to promote adaptive re-use，shaping the image of cultural and eco-industrial cultural landscape，realizing the direction of the transformation of sustainable cultural and creative industries，as well as implementing the multi-level policy actions of the government regulatory agencies． This mode provided a reference for protection，development and utilization of industrial heritages in China．
