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2015 Vol. 45, No. 10
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2015, 45(10): 1-6.
doi: 10.13204/j.gyjz201510001
Abstract:
The prefabricated steel structure is highly efficient in construction because of its industrial production and modular installation． The structure is different from the traditional steel frame and its dynamic behavior under earthquake needs． The elasto-plastic dynamic time history analysis was conducted for the prefabricated steel frame structure with and without inclined support joints under 7 degree earthquake． The results showed that the overall stiffness of structure increased greatly because of the inclined support joints and the deformation was reduced obviously under the 7 degree earthquake and the top maximum displacement of the structure was reduced by 56. 6% while the maximum interlayer displacement angle was reduced by 61. 3% under artificial waves，most of the plastic hinge appeared in the webs of the truss girder and the columns were in elastic stage．
The prefabricated steel structure is highly efficient in construction because of its industrial production and modular installation． The structure is different from the traditional steel frame and its dynamic behavior under earthquake needs． The elasto-plastic dynamic time history analysis was conducted for the prefabricated steel frame structure with and without inclined support joints under 7 degree earthquake． The results showed that the overall stiffness of structure increased greatly because of the inclined support joints and the deformation was reduced obviously under the 7 degree earthquake and the top maximum displacement of the structure was reduced by 56. 6% while the maximum interlayer displacement angle was reduced by 61. 3% under artificial waves，most of the plastic hinge appeared in the webs of the truss girder and the columns were in elastic stage．
2015, 45(10): 7-12.
doi: 10.13204/j.gyjz201510002
Abstract:
For studying the aseismic performance of the prefabricated steel frame with inclined support joints，the Pushover analysis was applied on one 30-story prefabricated steel frame and compared with analysis results of the frame without inclined support． Analysis result showed that under 7-degree rare earthquake，the maximum drift was 1 /223，which was less than 1 /50 specified by the code，hence this building structure could meet the principle ofno collapse under seldom earthquake actionin the national seismic design code; the arrangement of inclined support could reduce the deformation of the structure under severe earthquake，and the top displacement and the maximum drift of the structure were reduced by 33. 4% ～ 38. 1% and 19. 3% ～ 40. 1% respectively． Most of plastic hinges occurred on positions of web members of the truss girder，and frame columns were in elastic stage．
For studying the aseismic performance of the prefabricated steel frame with inclined support joints，the Pushover analysis was applied on one 30-story prefabricated steel frame and compared with analysis results of the frame without inclined support． Analysis result showed that under 7-degree rare earthquake，the maximum drift was 1 /223，which was less than 1 /50 specified by the code，hence this building structure could meet the principle ofno collapse under seldom earthquake actionin the national seismic design code; the arrangement of inclined support could reduce the deformation of the structure under severe earthquake，and the top displacement and the maximum drift of the structure were reduced by 33. 4% ～ 38. 1% and 19. 3% ～ 40. 1% respectively． Most of plastic hinges occurred on positions of web members of the truss girder，and frame columns were in elastic stage．
2015, 45(10): 13-17.
doi: 10.13204/j.gyjz201510003
Abstract:
There are no unified assessment standards of progressive collapse due to the complex mechanism of progressive collapse both at home and abroad so far． The adaptability of the evaluation index of antiprogressive collapse capacity specified by Guidelines for Collapse Control Design of Steel Structures with High Ｒedundancy of Japan to the prefabricated steel frame structures with inclined support joints was verified by 3 examples of 4-span and 5-story prefabricated steel frame structures with inclined support joints． Based on the subject of a nine-story prefabricated steel frame structure with inclined support joints，corner column，short side middle column，long side middle column and inside middle column were removed with the alternative load path method，the performance evaluation of antiprogressive collapse was conducted with performance evaluation method raised above，the result showed that structures performance of resisting progressive collapse turned out to be able to meet the need，the structures antiprogressive collapse performance after removing corner column was much better than that of removing inner column． In addition，the safety margin of trussed beam was lower than that of the column．
There are no unified assessment standards of progressive collapse due to the complex mechanism of progressive collapse both at home and abroad so far． The adaptability of the evaluation index of antiprogressive collapse capacity specified by Guidelines for Collapse Control Design of Steel Structures with High Ｒedundancy of Japan to the prefabricated steel frame structures with inclined support joints was verified by 3 examples of 4-span and 5-story prefabricated steel frame structures with inclined support joints． Based on the subject of a nine-story prefabricated steel frame structure with inclined support joints，corner column，short side middle column，long side middle column and inside middle column were removed with the alternative load path method，the performance evaluation of antiprogressive collapse was conducted with performance evaluation method raised above，the result showed that structures performance of resisting progressive collapse turned out to be able to meet the need，the structures antiprogressive collapse performance after removing corner column was much better than that of removing inner column． In addition，the safety margin of trussed beam was lower than that of the column．
2015, 45(10): 18-23.
doi: 10.13204/j.gyjz201510004
Abstract:
Compared with traditional solid web steel beams，the holes in the web of truss girders in the prefabricated steel structure of housing system enable the pipelines to pass through easily，which provides a higher room clear height and makes the structure economical and decorated． Experimental research and nonlinear finite element analysis of the steel truss girder were carried out． The ultimate bearing capacity and deformation characteristic of the steel truss girder were obtained． The failure zone mainly occurred at top chord near the loading point，and none of the web members reached the yield strain． When the girder was damaged，webs were at a relatively small force damaged after the chord，which could meet the design requirements of strong shear and weak bending． The big difference between yield load and ultimate load made the members have a large safety reserve． The finite element analysis results and the experiment results were verified each other，showing a better agreement．
Compared with traditional solid web steel beams，the holes in the web of truss girders in the prefabricated steel structure of housing system enable the pipelines to pass through easily，which provides a higher room clear height and makes the structure economical and decorated． Experimental research and nonlinear finite element analysis of the steel truss girder were carried out． The ultimate bearing capacity and deformation characteristic of the steel truss girder were obtained． The failure zone mainly occurred at top chord near the loading point，and none of the web members reached the yield strain． When the girder was damaged，webs were at a relatively small force damaged after the chord，which could meet the design requirements of strong shear and weak bending． The big difference between yield load and ultimate load made the members have a large safety reserve． The finite element analysis results and the experiment results were verified each other，showing a better agreement．
2015, 45(10): 24-30.
doi: 10.13204/j.gyjz201510005
Abstract:
Due to the difficulty to do structural calculation and the big quantity of truss beam members in the prefabricated steel frame structure with diagonal bracing，this paper proposed a simplified calculation method by equating steel truss beams with solid I-steel beams according to the principle of equal stiffness，equal height and equal flanges． 5 equivalent beam sections figures were obtained by considering the 4 boundary conditions: simply supported beam subject to uniform loads，simply supported beam subject to point loads at mid-span，cantilever beam subject to uniform loads and cantilever beam subject to point loads at free end． SAP 2000 was applied to build an actual structural calculation model and equivalent ones of a 20-storey prefabricated steel frame structure with diagonal bracing joints． The structural calculation was performed to give a comparison of the key indexes such as mode periods，drift，inter-story drift angle，shear-weight ratio，rigidity-to-gravity ratio and so on． The best match happened between the results achieved in the boundary condition of simply supported beam subject to uniform loads and the actual model． It was proved that this method could be used in integral structure analysis and design for the prefabricated steel frame structure with diagonal bracing and other similar structures．
Due to the difficulty to do structural calculation and the big quantity of truss beam members in the prefabricated steel frame structure with diagonal bracing，this paper proposed a simplified calculation method by equating steel truss beams with solid I-steel beams according to the principle of equal stiffness，equal height and equal flanges． 5 equivalent beam sections figures were obtained by considering the 4 boundary conditions: simply supported beam subject to uniform loads，simply supported beam subject to point loads at mid-span，cantilever beam subject to uniform loads and cantilever beam subject to point loads at free end． SAP 2000 was applied to build an actual structural calculation model and equivalent ones of a 20-storey prefabricated steel frame structure with diagonal bracing joints． The structural calculation was performed to give a comparison of the key indexes such as mode periods，drift，inter-story drift angle，shear-weight ratio，rigidity-to-gravity ratio and so on． The best match happened between the results achieved in the boundary condition of simply supported beam subject to uniform loads and the actual model． It was proved that this method could be used in integral structure analysis and design for the prefabricated steel frame structure with diagonal bracing and other similar structures．
2015, 45(10): 31-35.
doi: 10.13204/j.gyjz201510006
Abstract:
Taking Xiao Tiancheng 57-story tall steel structure as background，harmonic superposition method and MATLAB were used to simulate fluctuating wind speed curve and fluctuating pressure curve in the class B topography． The structure calculation model was established by the finite element software MIDAS Gen to analyze structural wind induced vibration of the structure under along-wind pressure． The results showed that the vertex peak acceleration of the structure calculated by the FE software was basically agreed with that by the formulas in National Building Code of Canada and Chinese Technical Specifications of Civil Tall Building Steel Structure ( JGJ 9998) ． According to Chinese Load Specification of Building Structure ( GB 500092012) ，the vertex peak acceleration of Xiao Tiancheng project could meet the requirements of specification limits when structural damping radio of steel house was taken as 0. 02．
Taking Xiao Tiancheng 57-story tall steel structure as background，harmonic superposition method and MATLAB were used to simulate fluctuating wind speed curve and fluctuating pressure curve in the class B topography． The structure calculation model was established by the finite element software MIDAS Gen to analyze structural wind induced vibration of the structure under along-wind pressure． The results showed that the vertex peak acceleration of the structure calculated by the FE software was basically agreed with that by the formulas in National Building Code of Canada and Chinese Technical Specifications of Civil Tall Building Steel Structure ( JGJ 9998) ． According to Chinese Load Specification of Building Structure ( GB 500092012) ，the vertex peak acceleration of Xiao Tiancheng project could meet the requirements of specification limits when structural damping radio of steel house was taken as 0. 02．
2015, 45(10): 36-41.
doi: 10.13204/j.gyjz201510007
Abstract:
The floor vibration responses induced human of the new type assembly prefabricated steel concrete composite slab used in the building named Xiao Tiancheng were measured and computed，it was obtained the peak acceleration due to vertical vibrations of the new type floor under six kinds of load cases，i． e single person walking， five people walking，single person running，five people running，single person jumping and five people jumping． The analysis results were in good agreement with the test results． Loading modes，walking route and load frequency which influenced the peak acceleration were analyzed． The results indicated that the jump was the most unfavorable loading mode for floor vibration; the more people，the greater the floor vibration; high order harmonic component of pedestrian load could cause the resonance of the floor; the new type of floor could meet the comfort requirement．
The floor vibration responses induced human of the new type assembly prefabricated steel concrete composite slab used in the building named Xiao Tiancheng were measured and computed，it was obtained the peak acceleration due to vertical vibrations of the new type floor under six kinds of load cases，i． e single person walking， five people walking，single person running，five people running，single person jumping and five people jumping． The analysis results were in good agreement with the test results． Loading modes，walking route and load frequency which influenced the peak acceleration were analyzed． The results indicated that the jump was the most unfavorable loading mode for floor vibration; the more people，the greater the floor vibration; high order harmonic component of pedestrian load could cause the resonance of the floor; the new type of floor could meet the comfort requirement．
2015, 45(10): 42-47.
doi: 10.13204/j.gyjz201510008
Abstract:
Prefabricated steel frame structure with inclined support joints is a new kind of steel structure，currently the studies of its construction simulation is few． In this paper，a 30-story prefabricated steel frame structure with inclined support joints was taken as engineering background． It was simulated to obtain the law of vertical deformation of the prefabricated steel frame structure with inclined support joints in construction simulation． At the same time，the influence of inclined support on vertical displacement of the 30-story prefabricated steel frame structure with inclined support joints in construction simulation was studied; getting the conclusion that inclined support had great impact on the vertical displacement of corner column and middle column，but had little impact on side column．
Prefabricated steel frame structure with inclined support joints is a new kind of steel structure，currently the studies of its construction simulation is few． In this paper，a 30-story prefabricated steel frame structure with inclined support joints was taken as engineering background． It was simulated to obtain the law of vertical deformation of the prefabricated steel frame structure with inclined support joints in construction simulation． At the same time，the influence of inclined support on vertical displacement of the 30-story prefabricated steel frame structure with inclined support joints in construction simulation was studied; getting the conclusion that inclined support had great impact on the vertical displacement of corner column and middle column，but had little impact on side column．
2015, 45(10): 48-52.
doi: 10.13204/j.gyjz201510009
Abstract:
Normally buildings from start of construction to being put into use，their main structures have been under a state of sun exposure． In this process，the change in temperature will have an effect on the deformations and internal forces of the structures． Based on a prefabricated steel frame structure with inclined support joints，the unit activation and deactivation function of MIDAS Gen were used to simulate all of the actual construction processes，of which the extreme temperature difference of the sun surface and the back sun face was used to simulate the thermal effect and applied them to the model． Then it was contrasted the difference of considering temperature and without considering it，there were obvious differences in the internal force and deformation of the structural members，showing that it is necessary to consider the construction process according to actual conditions．
Normally buildings from start of construction to being put into use，their main structures have been under a state of sun exposure． In this process，the change in temperature will have an effect on the deformations and internal forces of the structures． Based on a prefabricated steel frame structure with inclined support joints，the unit activation and deactivation function of MIDAS Gen were used to simulate all of the actual construction processes，of which the extreme temperature difference of the sun surface and the back sun face was used to simulate the thermal effect and applied them to the model． Then it was contrasted the difference of considering temperature and without considering it，there were obvious differences in the internal force and deformation of the structural members，showing that it is necessary to consider the construction process according to actual conditions．
2015, 45(10): 53-60.
doi: 10.13204/j.gyjz201510010
Abstract:
Currently it is an important task for the construction of traditional village to develop infrastructure and improve human settlements． In fact，due to lack of scientific guide，traditional village infrastructure is often in conflict with the local social economy，traditional scenes，eco-environment． In this paper，improved analytic hierarchy process was used to build evaluation system of traditional village infrastructure coordinated development， coordination degree model was set up，coordinated development degree and coordinated development trend model were borrowed to discuss the internal relations between development of traditional village infrastructure and society， economy，history as well as ecosystem． It was also helpful to get the corresponding level of coordinated development degree to find out the problems existed in the construction of traditional village infrastructure and to find solutions，so as to provide some evidences for planning and management of coordinated development of traditional village infrastructure．
Currently it is an important task for the construction of traditional village to develop infrastructure and improve human settlements． In fact，due to lack of scientific guide，traditional village infrastructure is often in conflict with the local social economy，traditional scenes，eco-environment． In this paper，improved analytic hierarchy process was used to build evaluation system of traditional village infrastructure coordinated development， coordination degree model was set up，coordinated development degree and coordinated development trend model were borrowed to discuss the internal relations between development of traditional village infrastructure and society， economy，history as well as ecosystem． It was also helpful to get the corresponding level of coordinated development degree to find out the problems existed in the construction of traditional village infrastructure and to find solutions，so as to provide some evidences for planning and management of coordinated development of traditional village infrastructure．
2015, 45(10): 61-64.
doi: 10.13204/j.gyjz201510011
Abstract:
Urban mining landscape park is a pattern of mining brownfield regeneration，which locates in urban area， inherits mining culture，integrates urban functions and serves urban community． Firstly，the characteristics of Gushuyuan Industrial Area were put forward，such as closure，complexity etc． Then it was emphasized the importance of integrating the idea of mine-city coordinationinto the park planning and design． Finally the project was introduced from three levels: city，site and building，achieving the change fromclosetofusion．
Urban mining landscape park is a pattern of mining brownfield regeneration，which locates in urban area， inherits mining culture，integrates urban functions and serves urban community． Firstly，the characteristics of Gushuyuan Industrial Area were put forward，such as closure，complexity etc． Then it was emphasized the importance of integrating the idea of mine-city coordinationinto the park planning and design． Finally the project was introduced from three levels: city，site and building，achieving the change fromclosetofusion．
2015, 45(10): 65-68.
doi: 10.13204/j.gyjz201510012
Abstract:
The abandoned railway is closely related to the city growth，which is the important carrier of city memory and tine witness of city development． Firstly，the status，characteristics and the landscape possibility of abandoned railway were discussed． And then the development，design concept，partition and development experience of Kwangju Greenway Park were introduced． Finally，it was given that the reference and enlightenment from the strategy emerging into city culture，industrial heritage reusing，combining with city greenway concept and focusing on concept of collaborative planning．
The abandoned railway is closely related to the city growth，which is the important carrier of city memory and tine witness of city development． Firstly，the status，characteristics and the landscape possibility of abandoned railway were discussed． And then the development，design concept，partition and development experience of Kwangju Greenway Park were introduced． Finally，it was given that the reference and enlightenment from the strategy emerging into city culture，industrial heritage reusing，combining with city greenway concept and focusing on concept of collaborative planning．
2015, 45(10): 69-73.
doi: 10.13204/j.gyjz201510013
Abstract:
The probabilistic model of resistance and partial factors of concrete beam given in Unified Standard for Ｒeliability Design of Building Structures ( GB 500682001) are mainly applicable to the common concrete beam， and it lacks full considerations of influences of prestress． To overcome this shortcoming，a refined probabilistic model of resistance was obtained under different amounts of reinforced steel and prestressing tendon，using the Monte Carlo sampling method，as well as combining with the current probabilistic models of all resistant factors and the capacity formulas in codes． Then，the influences of interesting parameters on reliability index were analyzed for prestressed concrete beam． The results showed that the corresponding design reliability indexes were increased largely with the increase of the amount of prestressed tendons，thus the differences from the target ones were underestimated for both seismic combination and non-seismic combination if they were represented by the reliability indexes of the common concrete beam only．
The probabilistic model of resistance and partial factors of concrete beam given in Unified Standard for Ｒeliability Design of Building Structures ( GB 500682001) are mainly applicable to the common concrete beam， and it lacks full considerations of influences of prestress． To overcome this shortcoming，a refined probabilistic model of resistance was obtained under different amounts of reinforced steel and prestressing tendon，using the Monte Carlo sampling method，as well as combining with the current probabilistic models of all resistant factors and the capacity formulas in codes． Then，the influences of interesting parameters on reliability index were analyzed for prestressed concrete beam． The results showed that the corresponding design reliability indexes were increased largely with the increase of the amount of prestressed tendons，thus the differences from the target ones were underestimated for both seismic combination and non-seismic combination if they were represented by the reliability indexes of the common concrete beam only．
2015, 45(10): 74-78.
doi: 10.13204/j.gyjz201510014
Abstract:
A finite element model of 160 000 m3 LNG reservoir tank was established to do the numerical simulation of the structure response，the formula of additional mass standard was deduced，the liquid-solid coupling effect in the dynamic response could be characterized by additional mass method，based on which the structure response of LNG reservoir tank under the action of earthquake was analyzed and then the stress time-history was achieved． According to the characteristics that the structure response of LNG reservoir tank was complicated by high degree nonlinearity，the simulation of the complex relationship between stochastic parameters and system response could be done based on stochastic response surface method，and the complex relationship was transformed to the function of standard random variables by Hermite polynomial． Thereby，limit state equation was established to obtain the reliability corresponding to the structural failure criteria．
A finite element model of 160 000 m3 LNG reservoir tank was established to do the numerical simulation of the structure response，the formula of additional mass standard was deduced，the liquid-solid coupling effect in the dynamic response could be characterized by additional mass method，based on which the structure response of LNG reservoir tank under the action of earthquake was analyzed and then the stress time-history was achieved． According to the characteristics that the structure response of LNG reservoir tank was complicated by high degree nonlinearity，the simulation of the complex relationship between stochastic parameters and system response could be done based on stochastic response surface method，and the complex relationship was transformed to the function of standard random variables by Hermite polynomial． Thereby，limit state equation was established to obtain the reliability corresponding to the structural failure criteria．
2015, 45(10): 79-83.
doi: 10.13204/j.gyjz201510015
Abstract:
According to the experimental investigation on the three small span-depth ratio ultrahigh toughness cementitious composite specimens and one ＲC coupling beam specimen under low cyclic reversed loading，the failure patterns and the mechanical behaviors of the coupling beam specimens such as load displacement hysteretic loops and strain of the steel were analyzed． It was also studied the effect of changing span-depth ratio of the specimens on seismic behavior of coupling beams． Test results indicated that the destroy mode of small span-depth ratio coupling beams due to their better toughness had the trend from brittleness to ductility; and the hysteretic loops of ultrahigh toughness cementitious composite coupling beam specimens showed a reversed S shape，but hysteretic loops were fuller than those of reinforced concrete coupling beam specimens． Steel bar yielded in the process of the test． Ultrahigh toughness cementitious composite can improve the seismic performance of coupling beams and meet the requirements of engineering design．
According to the experimental investigation on the three small span-depth ratio ultrahigh toughness cementitious composite specimens and one ＲC coupling beam specimen under low cyclic reversed loading，the failure patterns and the mechanical behaviors of the coupling beam specimens such as load displacement hysteretic loops and strain of the steel were analyzed． It was also studied the effect of changing span-depth ratio of the specimens on seismic behavior of coupling beams． Test results indicated that the destroy mode of small span-depth ratio coupling beams due to their better toughness had the trend from brittleness to ductility; and the hysteretic loops of ultrahigh toughness cementitious composite coupling beam specimens showed a reversed S shape，but hysteretic loops were fuller than those of reinforced concrete coupling beam specimens． Steel bar yielded in the process of the test． Ultrahigh toughness cementitious composite can improve the seismic performance of coupling beams and meet the requirements of engineering design．
2015, 45(10): 84-89.
doi: 10.13204/j.gyjz201510016
Abstract:
To study the mechanical property and constraint mechanism of concrete columns confined by TRC under uniaxial compression，24 concrete columns confined by TRC and 8 unstrengthened concrete columns were designed based on textile ratio，section dimension and strength of concrete，and axial compressive tests were carried out． Based on the test results，stress process and failure mode of strengthened members were studied，stress-strain relationship of strengthened members was researched，effect of textile ratio，section dimension and concrete strength on ultimate strength of strengthened members was also evaluated． The results showed that the strength and deformability of the strengthened members increased，and the strengthened members showed drum-shaped shear damage． With the increasing of textile ratio，the confining effect of TRC on the concrete increased． With the increasing of section dimension，the confining effect of TRC on the concrete decreased． The confining effect of TRC on low strength concrete was stronger． The formulas of concrete columns confined by TRC were proposed． The calculated results agreed well with test results．
To study the mechanical property and constraint mechanism of concrete columns confined by TRC under uniaxial compression，24 concrete columns confined by TRC and 8 unstrengthened concrete columns were designed based on textile ratio，section dimension and strength of concrete，and axial compressive tests were carried out． Based on the test results，stress process and failure mode of strengthened members were studied，stress-strain relationship of strengthened members was researched，effect of textile ratio，section dimension and concrete strength on ultimate strength of strengthened members was also evaluated． The results showed that the strength and deformability of the strengthened members increased，and the strengthened members showed drum-shaped shear damage． With the increasing of textile ratio，the confining effect of TRC on the concrete increased． With the increasing of section dimension，the confining effect of TRC on the concrete decreased． The confining effect of TRC on low strength concrete was stronger． The formulas of concrete columns confined by TRC were proposed． The calculated results agreed well with test results．
2015, 45(10): 90-95.
doi: 10.13204/j.gyjz201510017
Abstract:
As a new kind of structure system，middle-high ecological hybrid composite wall structure is ecological， environmental，energy-saving，and has the advantage of energy dissipation and vibration reduction． Besides，it can be built rapidly． The system is mainly composed of prefabricated concrete vertical constraint components，hidden beam and assembly cast-in-place floor slab． The results indicated that under horizontal load，block，sash and frame could interact，and bear loads together． They played a role in turn in elastic stage，elastic-plastic stage and failure stage of the test． This made the middle-high ecological composite wall end up with multiple seismic linesblock-sash-vertical constraint component． On the basis of experimental study，the finite element software was used to analyze the influence factors of each line of defense，the effect of block strength for the first defense line，the size of the rib beam and frame column，the reinforcement of rib beam and rib column for the second defense line，the reinforcement of vertical constraint component for the third defense line． According to numerical analysis the influence rules of different factors were summarized which provided theory support for the later engineering practice． Studies showed that the matching between the relative strength and relative stiffness of different defense blocks，grid structures and three vertical restraint members was the effective guaranteed to realize three seismic lines． The seismic design method of the middlehigh ecological composite wall hybrid structure on the basis of three seismic lines could satisfy the personalized requirements of the performance goals design in structure．
As a new kind of structure system，middle-high ecological hybrid composite wall structure is ecological， environmental，energy-saving，and has the advantage of energy dissipation and vibration reduction． Besides，it can be built rapidly． The system is mainly composed of prefabricated concrete vertical constraint components，hidden beam and assembly cast-in-place floor slab． The results indicated that under horizontal load，block，sash and frame could interact，and bear loads together． They played a role in turn in elastic stage，elastic-plastic stage and failure stage of the test． This made the middle-high ecological composite wall end up with multiple seismic linesblock-sash-vertical constraint component． On the basis of experimental study，the finite element software was used to analyze the influence factors of each line of defense，the effect of block strength for the first defense line，the size of the rib beam and frame column，the reinforcement of rib beam and rib column for the second defense line，the reinforcement of vertical constraint component for the third defense line． According to numerical analysis the influence rules of different factors were summarized which provided theory support for the later engineering practice． Studies showed that the matching between the relative strength and relative stiffness of different defense blocks，grid structures and three vertical restraint members was the effective guaranteed to realize three seismic lines． The seismic design method of the middlehigh ecological composite wall hybrid structure on the basis of three seismic lines could satisfy the personalized requirements of the performance goals design in structure．
2015, 45(10): 96-100.
doi: 10.13204/j.gyjz201510018
Abstract:
Having studied bending and compressing-bending ultimate failure test of three new EVG － 3D walls，the mechanical characteristics of wall panels，combined action of two plates of concrete and the steel wires with concrete were analyzed in this paper． Based on the test results of bending and compressing-bending of EVG － 3D wall panels， calculation formulas for flexural and shear bearing capacity were researched simultaneously． These results obtained are served as a basis for compiling engineering regulations of this new composite wall material．
Having studied bending and compressing-bending ultimate failure test of three new EVG － 3D walls，the mechanical characteristics of wall panels，combined action of two plates of concrete and the steel wires with concrete were analyzed in this paper． Based on the test results of bending and compressing-bending of EVG － 3D wall panels， calculation formulas for flexural and shear bearing capacity were researched simultaneously． These results obtained are served as a basis for compiling engineering regulations of this new composite wall material．
2015, 45(10): 101-105.
doi: 10.13204/j.gyjz201510019
Abstract:
Based on the twin shear unified strength theory，the unified solution of Coulombs passive earth pressure for unsaturated soils was deduced by considering the influence of intermediate principal stress and the matric suction，etc． Through comparing the calculation results of the proposed formula with those of the unified solutions of Ｒankines passive earth pressure，the rationality of the proposed formula was verified． Additionally，the effects of parameters on Coulombs passive earth pressure were discussed，including the intermediate principal stress，the matric suction and the friction angle． The results indicated that the unified solution of Coulombs passive earth pressure for unsaturated soils had very broad applications． The Coulombs passive earth pressure of saturated soils and the Ｒankines passive earth pressure of unsaturated soils just were the special cases． The intermediate principal stress，the matric suction and the friction angle had significant influence on the Coulombs passive earth pressure，and the Coulombs passive earth pressure increased with the increase of unified strength theory parameter，matric suction and friction angle．
Based on the twin shear unified strength theory，the unified solution of Coulombs passive earth pressure for unsaturated soils was deduced by considering the influence of intermediate principal stress and the matric suction，etc． Through comparing the calculation results of the proposed formula with those of the unified solutions of Ｒankines passive earth pressure，the rationality of the proposed formula was verified． Additionally，the effects of parameters on Coulombs passive earth pressure were discussed，including the intermediate principal stress，the matric suction and the friction angle． The results indicated that the unified solution of Coulombs passive earth pressure for unsaturated soils had very broad applications． The Coulombs passive earth pressure of saturated soils and the Ｒankines passive earth pressure of unsaturated soils just were the special cases． The intermediate principal stress，the matric suction and the friction angle had significant influence on the Coulombs passive earth pressure，and the Coulombs passive earth pressure increased with the increase of unified strength theory parameter，matric suction and friction angle．
2015, 45(10): 106-110.
doi: 10.13204/j.gyjz201510020
Abstract:
With the help of the true triaxial apparatus，plane strain tests of remolded loess were conducted in order to study the stress-strain relationship，the changing characteristics of intermediate principal stress and shear strength of remolded loess in plane strain condition． The test results showed that the stress-strain relationship curves of remolded loess were the hardening or strong hardening type during vertical principal stress loading． Under condition of the same coefficient of compaction and confining pressure，the smaller the moisture content was，the greater the strength of remolded loess was． On condition of the same moisture content and confining pressure，the greater the coefficient of compaction was，the higher the strength of remolded loess was． On condition of the same moisture content and coefficient of compaction，the greater the confining pressure was，the higher the strength of remolded loess was． The intermediate principal stress increased with the growth of axial strain． The greater the confining pressure and the smaller the moisture content were，the greater the intermediate principal stress was． With the moisture content being increased，the cohesion was reduced obviously and the internal friction angle was decreased slightly; with the coefficient of compaction being increased，the cohesion was increased significantly and the internal friction angle was almost constant．
With the help of the true triaxial apparatus，plane strain tests of remolded loess were conducted in order to study the stress-strain relationship，the changing characteristics of intermediate principal stress and shear strength of remolded loess in plane strain condition． The test results showed that the stress-strain relationship curves of remolded loess were the hardening or strong hardening type during vertical principal stress loading． Under condition of the same coefficient of compaction and confining pressure，the smaller the moisture content was，the greater the strength of remolded loess was． On condition of the same moisture content and confining pressure，the greater the coefficient of compaction was，the higher the strength of remolded loess was． On condition of the same moisture content and coefficient of compaction，the greater the confining pressure was，the higher the strength of remolded loess was． The intermediate principal stress increased with the growth of axial strain． The greater the confining pressure and the smaller the moisture content were，the greater the intermediate principal stress was． With the moisture content being increased，the cohesion was reduced obviously and the internal friction angle was decreased slightly; with the coefficient of compaction being increased，the cohesion was increased significantly and the internal friction angle was almost constant．
2015, 45(10): 111-115.
doi: 10.13204/j.gyjz201510021
Abstract:
It was analyzed the law of the transmission and attenuation of vacuum pressure，the growth and dissipation of excess pore pressure，ground surface settlement，and the deformation characteristic and rules of layered settlement in the deep soft soil foundation covered by unconsolidated hydraulic fill of fine silty sand，and also studied the effects on consolidation deformation of the soft soil foundation covered by unconsolidated hydraulic fill of fine silt layer． Unconsolidated hydraulic fill of fine silty sand was conducive to the pore pressure dissipation and the drainage of underlying deep soft foundation． The foundation settlement was fast with fluctuation in the early stage，convergence and stability in the middle and later stage． When vacuum pressure under membrane transferred on the surface，its difference and fluctuation were large，when it passed to the deep foundation，its hysteresis and attenuation range was large． The compression of unconsolidated hydraulic fill of silty sand was large，and most of the vacuum energy was absorbed． The characteristic was not conducive to the compression deformation of underlying deep soft foundation． After treatment，the reinforcing effect of the unconsolidated hydraulic fill of silty sand was better than the underlying deep soft foundation．
It was analyzed the law of the transmission and attenuation of vacuum pressure，the growth and dissipation of excess pore pressure，ground surface settlement，and the deformation characteristic and rules of layered settlement in the deep soft soil foundation covered by unconsolidated hydraulic fill of fine silty sand，and also studied the effects on consolidation deformation of the soft soil foundation covered by unconsolidated hydraulic fill of fine silt layer． Unconsolidated hydraulic fill of fine silty sand was conducive to the pore pressure dissipation and the drainage of underlying deep soft foundation． The foundation settlement was fast with fluctuation in the early stage，convergence and stability in the middle and later stage． When vacuum pressure under membrane transferred on the surface，its difference and fluctuation were large，when it passed to the deep foundation，its hysteresis and attenuation range was large． The compression of unconsolidated hydraulic fill of silty sand was large，and most of the vacuum energy was absorbed． The characteristic was not conducive to the compression deformation of underlying deep soft foundation． After treatment，the reinforcing effect of the unconsolidated hydraulic fill of silty sand was better than the underlying deep soft foundation．
2015, 45(10): 116-120.
doi: 10.13204/j.gyjz201510022
Abstract:
In this paper，soft soil reinforced by slag and cement in Nansha ( Guangzhou) was studied． Through conventional soil test including direct shear test and unconfined compression test，reinforced soils mechanical property was researched and the correlation among its internal friction angle( IFA) ，cohesion，unconfined compressive strength( UCS) and mix ratio or curing age were studied． Scanning electron microscope observation( SEM) and X-ray diffraction technique( XRD) were used to study different microstructure characteristics and the mineral composition of different reinforced soil samples． The results showed that the IFA，cohesion and UCS of reinforced soil were raised increasing with the ratio of slag in curing agent，and cohesion was increased most obviously． The optimum was application of 60% slag，and the higher the ratio of slag be adopted，the faster the later strength of reinforced cement soil was raised． All of that were related to the microstructure and hydration products of reinforced soil．
In this paper，soft soil reinforced by slag and cement in Nansha ( Guangzhou) was studied． Through conventional soil test including direct shear test and unconfined compression test，reinforced soils mechanical property was researched and the correlation among its internal friction angle( IFA) ，cohesion，unconfined compressive strength( UCS) and mix ratio or curing age were studied． Scanning electron microscope observation( SEM) and X-ray diffraction technique( XRD) were used to study different microstructure characteristics and the mineral composition of different reinforced soil samples． The results showed that the IFA，cohesion and UCS of reinforced soil were raised increasing with the ratio of slag in curing agent，and cohesion was increased most obviously． The optimum was application of 60% slag，and the higher the ratio of slag be adopted，the faster the later strength of reinforced cement soil was raised． All of that were related to the microstructure and hydration products of reinforced soil．
2015, 45(10): 121-125.
doi: 10.13204/j.gyjz201510023
Abstract:
The polarization behavior of rebar with mill scale and stains was investigated in simulated solutions with and without chlorions． The results showed that the hot-rolled rebar without and with stains could be passivated in strong alkali solutions without chloride，but the latter usually needs higher passive current density． Dense mill scale had some protective function when pH = 10 ～ 12. 5，but became unstable when pH13. 5． The rebar with dense mill scale and without stains also could be passivated in strong alkali solutions with some chlorides，but the rusted one kept being in active corrosion state．
The polarization behavior of rebar with mill scale and stains was investigated in simulated solutions with and without chlorions． The results showed that the hot-rolled rebar without and with stains could be passivated in strong alkali solutions without chloride，but the latter usually needs higher passive current density． Dense mill scale had some protective function when pH = 10 ～ 12. 5，but became unstable when pH13. 5． The rebar with dense mill scale and without stains also could be passivated in strong alkali solutions with some chlorides，but the rusted one kept being in active corrosion state．
2015, 45(10): 126-131.
doi: 10.13204/j.gyjz201510024
Abstract:
Self-compacting concrete was prepared with waste glass being used as fine aggregate． The influence of different replacement rate of waste glass on workability，mechanical properties and volume stability of self-compacting concrete was studied． The results showed that the waste glass could significantly improve the slump and reduce the slump loss with time; concrete prepared with waste glass met the requirements of both passing ability and segregation resistance． The mechanical properties were reduced with the increase of waste glass replacement rate． The weakening effect of waste glass was more significant in the higher strength concrete． Fly ash could effectively suppress the volume expansion caused by the waste glass． As a kind of qualified fine aggregate，waste glass could be used to produce a self-compacting concrete with high performance．
Self-compacting concrete was prepared with waste glass being used as fine aggregate． The influence of different replacement rate of waste glass on workability，mechanical properties and volume stability of self-compacting concrete was studied． The results showed that the waste glass could significantly improve the slump and reduce the slump loss with time; concrete prepared with waste glass met the requirements of both passing ability and segregation resistance． The mechanical properties were reduced with the increase of waste glass replacement rate． The weakening effect of waste glass was more significant in the higher strength concrete． Fly ash could effectively suppress the volume expansion caused by the waste glass． As a kind of qualified fine aggregate，waste glass could be used to produce a self-compacting concrete with high performance．
2015, 45(10): 132-137.
doi: 10.13204/j.gyjz201510025
Abstract:
Temperature monitoring is one of the important means for temperature control and anticrack the mass concrete construction process． However，there are still some drawbacks in the existing mass concrete temperature monitoring systems． For example there are large number of wires connecting to the temperature sensors，the monitoring parameters need to be calculated by hand． These drawbacks make the installation of temperature monitoring system very time-consuming and the information is not real-time． In this paper a mass concrete temperature monitoring system was developed，which was composed of wireless temperature sensors，wireless sensor networks and a smart monitoring software． The application of the monitoring system in the mass concrete construction of a large suspension bridge proved the convenience and reliability of the system． The features of automatic acquisition and storage of data，display and warning of the temperature of the mass concrete，data management and analysis made the system meet the requirements of the mass concrete temperature monitoring．
Temperature monitoring is one of the important means for temperature control and anticrack the mass concrete construction process． However，there are still some drawbacks in the existing mass concrete temperature monitoring systems． For example there are large number of wires connecting to the temperature sensors，the monitoring parameters need to be calculated by hand． These drawbacks make the installation of temperature monitoring system very time-consuming and the information is not real-time． In this paper a mass concrete temperature monitoring system was developed，which was composed of wireless temperature sensors，wireless sensor networks and a smart monitoring software． The application of the monitoring system in the mass concrete construction of a large suspension bridge proved the convenience and reliability of the system． The features of automatic acquisition and storage of data，display and warning of the temperature of the mass concrete，data management and analysis made the system meet the requirements of the mass concrete temperature monitoring．
2015, 45(10): 138-141.
doi: 10.13204/j.gyjz201510026
Abstract:
Upgraded pressurized water reactor of CPR1000 was adopted in Yangjiang Nuclear Power Plant ( NPP) ． Based on a series of mixing tests and site mockup test studies，self-compacting concrete ( SCC) technique was successfully applied to containment truncated cone of No． 4 unit for the first time in NPP building industry，which could provide references for relevant projects with similar prestressed concrete structures．
Upgraded pressurized water reactor of CPR1000 was adopted in Yangjiang Nuclear Power Plant ( NPP) ． Based on a series of mixing tests and site mockup test studies，self-compacting concrete ( SCC) technique was successfully applied to containment truncated cone of No． 4 unit for the first time in NPP building industry，which could provide references for relevant projects with similar prestressed concrete structures．
2015, 45(10): 142-149.
doi: 10.13204/j.gyjz201510027
Abstract:
Geotechnical centrifugal model test can present the state of stress actually，it is considered to be the most advanced and effective method in the study of the geotechnical engineering，including the excavation engineering． In this paper，the principle and advantages of the geotechnical model test were stated firstly． Secondly，the applications in various fields of geotechnical engineering in recent years were reviewed． Thirdly，the present state of the centrifugal model test in foundation pit engineering，as well as the key technology，including the preparation of the model，feasible foundation pit method，fabrication and installation of the supporting structure，measuring techniques and the others were described in detail． Lastly，the deficiencies and future development of centrifuge model test on foundation pit engineering were also presented．
Geotechnical centrifugal model test can present the state of stress actually，it is considered to be the most advanced and effective method in the study of the geotechnical engineering，including the excavation engineering． In this paper，the principle and advantages of the geotechnical model test were stated firstly． Secondly，the applications in various fields of geotechnical engineering in recent years were reviewed． Thirdly，the present state of the centrifugal model test in foundation pit engineering，as well as the key technology，including the preparation of the model，feasible foundation pit method，fabrication and installation of the supporting structure，measuring techniques and the others were described in detail． Lastly，the deficiencies and future development of centrifuge model test on foundation pit engineering were also presented．
2015, 45(10): 150-154.
doi: 10.13204/j.gyjz201510028
Abstract:
The column loading was adopted instead of the traditional symmetric beam-end loading to carry out the low cyclic reversed loading test on the mid-frame joint of T-section steel connection，which was more in accordance with the practical loading features． The test results showed that the maximum stress occurred at the junction between the flange and web of T-member，where the plastic hinge appeared firstly; during the loading process，the column flange and the beam flange were both at the elastic stage，yet the shear strain of the joint area turned into the yield strain． Meanwhile，the hysteretic curve and the skeleton curve testified the preferable ductility and energy dissipation of the joint．
The column loading was adopted instead of the traditional symmetric beam-end loading to carry out the low cyclic reversed loading test on the mid-frame joint of T-section steel connection，which was more in accordance with the practical loading features． The test results showed that the maximum stress occurred at the junction between the flange and web of T-member，where the plastic hinge appeared firstly; during the loading process，the column flange and the beam flange were both at the elastic stage，yet the shear strain of the joint area turned into the yield strain． Meanwhile，the hysteretic curve and the skeleton curve testified the preferable ductility and energy dissipation of the joint．
2015, 45(10): 155-160.
doi: 10.13204/j.gyjz201510029
Abstract:
In order to analyze accurately the influence of shear deformation on the mechanical characteristic of open thin-walled members，the shear stress non-uniform coefficient was correctly calculated by considering stress shear due to shear deformation． Based on the first-order thin-walled beam theory，the precise calculation formulas of several common open section shear stress non-uniform coefficient were got according to the principle of energy，some basic laws of the influences of the cross section shape and size parameters on the shear stress non-uniform coefficient were discussed． Results showed that as the aspect ratio increased，the shear stress non-uniform coefficient of channel section decreased first，then increased; it increased with the increase of the width-thickness ratio; as the depththickness ratio increased，the shear stress non-uniform coefficient decreases first，then increased． The shear stress non-uniform coefficient of Z section increased with the increase of aspect ratio; it decreased with increasing of the width-thickness ratio; and it increased with the increase of the depth-thickness ratio． The shear stress non-uniform coefficient of a biax symmetric I-section was a constant value．
In order to analyze accurately the influence of shear deformation on the mechanical characteristic of open thin-walled members，the shear stress non-uniform coefficient was correctly calculated by considering stress shear due to shear deformation． Based on the first-order thin-walled beam theory，the precise calculation formulas of several common open section shear stress non-uniform coefficient were got according to the principle of energy，some basic laws of the influences of the cross section shape and size parameters on the shear stress non-uniform coefficient were discussed． Results showed that as the aspect ratio increased，the shear stress non-uniform coefficient of channel section decreased first，then increased; it increased with the increase of the width-thickness ratio; as the depththickness ratio increased，the shear stress non-uniform coefficient decreases first，then increased． The shear stress non-uniform coefficient of Z section increased with the increase of aspect ratio; it decreased with increasing of the width-thickness ratio; and it increased with the increase of the depth-thickness ratio． The shear stress non-uniform coefficient of a biax symmetric I-section was a constant value．
2015, 45(10): 161-165.
doi: 10.13204/j.gyjz201510030
Abstract:
The orthotropic steel bridge deck finite element model was established to analyze the hot spot stress． Considering the wheel loads in different vertical and lateral position，the changing process of the hot spot stress and stress amplitude were analyzed． The influence of different axle types and the most unfavorable load position were studied． It was shown that longitudinal weld at different positions had the same stress amplitude when the wheel load was moving longitudinally． The damage degree calculation result of multiaxis load was in multiple relation to that of single axle load． So，multiaxis load can be equivalent to a multiple single axle load when doing calculations． According to the analysis，the most unfavorable position along transverse direction of double wheel load is just above the weld．
The orthotropic steel bridge deck finite element model was established to analyze the hot spot stress． Considering the wheel loads in different vertical and lateral position，the changing process of the hot spot stress and stress amplitude were analyzed． The influence of different axle types and the most unfavorable load position were studied． It was shown that longitudinal weld at different positions had the same stress amplitude when the wheel load was moving longitudinally． The damage degree calculation result of multiaxis load was in multiple relation to that of single axle load． So，multiaxis load can be equivalent to a multiple single axle load when doing calculations． According to the analysis，the most unfavorable position along transverse direction of double wheel load is just above the weld．
2015, 45(10): 166-170.
doi: 10.13204/j.gyjz201510031
Abstract:
Based on the elastic deformation theory，a mechanical model of composite beam under negative moment was established by considering the surface slip and vertical uplift effects． The differential equation was derived by using the principle of force equilibrium and deformation compatibility condition． Calculation program was developed and obtained the formula of vertical uplift force under negative moment． The results showed that composite beam under same load condition，the uplift force of single stud was increased with the increasing of distance between studs． All the numerical results were verified by comparing with experiment results to illustrate the accuracy and reliability of the calculation method． The result provided a theoretical basis for interface study considering the surface slip and vertical uplift effects of continuous composite beam．
Based on the elastic deformation theory，a mechanical model of composite beam under negative moment was established by considering the surface slip and vertical uplift effects． The differential equation was derived by using the principle of force equilibrium and deformation compatibility condition． Calculation program was developed and obtained the formula of vertical uplift force under negative moment． The results showed that composite beam under same load condition，the uplift force of single stud was increased with the increasing of distance between studs． All the numerical results were verified by comparing with experiment results to illustrate the accuracy and reliability of the calculation method． The result provided a theoretical basis for interface study considering the surface slip and vertical uplift effects of continuous composite beam．
2015, 45(10): 171-175.
doi: 10.13204/j.gyjz201510032
Abstract:
The heat transfer performance of concrete-filled steel tube buckling-restrained-brace was analyzed by ABAQUS． The results showed that the temperature distribution of core plate was uniform． And the temperature of core plate was only 25 percents of that of the outer tube． The changes in load-bearing capacities of BＲB under different fire durations were calculated according to Technical Code for Antifire of Building Steel Structure ( CECS 200 ∶ 2006) ． Under the results of FEM analysis，the recommend spraying range of fire retardant coatings of BＲB was presented．
The heat transfer performance of concrete-filled steel tube buckling-restrained-brace was analyzed by ABAQUS． The results showed that the temperature distribution of core plate was uniform． And the temperature of core plate was only 25 percents of that of the outer tube． The changes in load-bearing capacities of BＲB under different fire durations were calculated according to Technical Code for Antifire of Building Steel Structure ( CECS 200 ∶ 2006) ． Under the results of FEM analysis，the recommend spraying range of fire retardant coatings of BＲB was presented．
2015, 45(10): 176-182.
doi: 10.13204/j.gyjz201510033
Abstract:
The seismic behavior of a steel implanted storey-adding frame and a steel implanted storey-adding frame strengthened with CFRP sheet for 1/3 scale model was investigated under low cycle reversed load． The failure characteristics，hysteresis properties，rigidity degeneracy，displacement ductility and energy dissipation capacity of the two specimens were compared． The test results revealed that the cement based inorganic anchoring material used in structural anchorage had good mechanical properties． The seismic behavior of steel storey-adding frames was favorable． After the steel implanted joint was reinforced by CFRP sheet，the failure mechanism of the storey-adding frame was turned from hybrid hinged failure into beam hinged failure，and the seismic behavior of the structure was significantly improved．
The seismic behavior of a steel implanted storey-adding frame and a steel implanted storey-adding frame strengthened with CFRP sheet for 1/3 scale model was investigated under low cycle reversed load． The failure characteristics，hysteresis properties，rigidity degeneracy，displacement ductility and energy dissipation capacity of the two specimens were compared． The test results revealed that the cement based inorganic anchoring material used in structural anchorage had good mechanical properties． The seismic behavior of steel storey-adding frames was favorable． After the steel implanted joint was reinforced by CFRP sheet，the failure mechanism of the storey-adding frame was turned from hybrid hinged failure into beam hinged failure，and the seismic behavior of the structure was significantly improved．
2015, 45(10): 183-190.
doi: 10.13204/j.gyjz201510034
Abstract:
Being aimed at the post-anchoring joints of RC beams and columns widely applied in engineering practices of renovation and reinforcement of existing structures，the seismic performance of those post-anchored joints was researched experimentally． The specimens were designed according to the prototype structure with a scale of 1∶ 2． The multiple post-anchored joints in frame structure were considered comprehensively，including the post-cast column on the top of the intermediate frame，the post-cast beam and column on the top of the side frame，and the post-cast beam connected to the intermediate layer． At the same time，several post-anchoring methods were studied，such as reinforcement implanted directly，adding additional reinforcements，and strengthening the main reinforcements by welding steel strip hoop． During the whole experimental process，the laws of the cracks，failure pattern，ductility， energy dissipation capacity and stiffness degradation for different joints were researched carefully． The conclusions were got that the seismic performance of post-anchored joints could be remained by considering the design principle of strong column and weak beam，strong joint and weak member，and anchorage length． The ductility of the whole structure could be improved by strengthening connections． The integrity of the structure should be considered when the new-old beams were connected，so as to ensure the unified strengthening on both sides．
Being aimed at the post-anchoring joints of RC beams and columns widely applied in engineering practices of renovation and reinforcement of existing structures，the seismic performance of those post-anchored joints was researched experimentally． The specimens were designed according to the prototype structure with a scale of 1∶ 2． The multiple post-anchored joints in frame structure were considered comprehensively，including the post-cast column on the top of the intermediate frame，the post-cast beam and column on the top of the side frame，and the post-cast beam connected to the intermediate layer． At the same time，several post-anchoring methods were studied，such as reinforcement implanted directly，adding additional reinforcements，and strengthening the main reinforcements by welding steel strip hoop． During the whole experimental process，the laws of the cracks，failure pattern，ductility， energy dissipation capacity and stiffness degradation for different joints were researched carefully． The conclusions were got that the seismic performance of post-anchored joints could be remained by considering the design principle of strong column and weak beam，strong joint and weak member，and anchorage length． The ductility of the whole structure could be improved by strengthening connections． The integrity of the structure should be considered when the new-old beams were connected，so as to ensure the unified strengthening on both sides．
2015, 45(10): 191-195.
doi: 10.13204/j.gyjz201510035
Abstract:
Prestressed pipe pile is widely used in soft soil area due to its fast construction speed and high efficiency． However，the pipe piles are prone to floating，deviation，damage and fracture due to high water content，weak strength，poor stability for soft soil． As foundation excavation is needed for high-rise building with basement， construction accidents are more likely to occur when foundation soils are disturbed or piles are crashed． In light of project cases in typical soft soil of Huzhou Region，the paper showed conventional construction process of the pipe piles for high-rise building with basement and common pipe pile quality construction accidents，also analyzed the causes of the accident，and introduced treatment methods for the accident． Later detection and settlement observation indicated that the treated pile could meet the design requirements，and the building settlement was minor and even．
Prestressed pipe pile is widely used in soft soil area due to its fast construction speed and high efficiency． However，the pipe piles are prone to floating，deviation，damage and fracture due to high water content，weak strength，poor stability for soft soil． As foundation excavation is needed for high-rise building with basement， construction accidents are more likely to occur when foundation soils are disturbed or piles are crashed． In light of project cases in typical soft soil of Huzhou Region，the paper showed conventional construction process of the pipe piles for high-rise building with basement and common pipe pile quality construction accidents，also analyzed the causes of the accident，and introduced treatment methods for the accident． Later detection and settlement observation indicated that the treated pile could meet the design requirements，and the building settlement was minor and even．
2015, 45(10): 196-201.
doi: 10.13204/j.gyjz201510036
Abstract:
The application of BIM improves the level of metro construction management，and the first task of BIM application is to create a BIM model． On the basis of analyzing the deficiency and existing problems of the present modeling technology，this paper studied the metro engineering and researched the modeling process using BIM technology by applying BIM related theory and combining with representative project cases． The method of analyzing the requirements of BIM model，BIM-based key modeling technology of metro engineering to raise model accuracy， modeling efficiency and management efficiency，modeling procedure and its related practical key points were raised， which solved effectively many problems such as low accuracy of the model，low modeling efficiency etc existing in the present BIM modeling work．
The application of BIM improves the level of metro construction management，and the first task of BIM application is to create a BIM model． On the basis of analyzing the deficiency and existing problems of the present modeling technology，this paper studied the metro engineering and researched the modeling process using BIM technology by applying BIM related theory and combining with representative project cases． The method of analyzing the requirements of BIM model，BIM-based key modeling technology of metro engineering to raise model accuracy， modeling efficiency and management efficiency，modeling procedure and its related practical key points were raised， which solved effectively many problems such as low accuracy of the model，low modeling efficiency etc existing in the present BIM modeling work．
