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2014 Vol. 44, No. 08
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2014, 44(08): 1-6.
Abstract:
The development of industrial prefabricated steel structure especially conforms to the strategic requirement of dissolving excess production capacity，development of green building and ecological civilization construction in China． It is the only way to truly achieve industrialization and modernization for China's construction industry． It also ensures the quality and speed of post-disaster reconstruction and the urgent request of seismic safety． This paper analyzed the current bottleneck of industrialization of industrial prefabricated steel structure in China． The problems of industrial prefabricated steel structure system and innovation of the joint in the new structure system，standard specification establishment，global optimization of steel structure design of prefabricated steel structure system with diagonal bracing at joints，structural overall stability，the mainboard and column stability，severe earthquake elastoplastic analysis，experiment of single cross framework，performance experiment of flange bolt connection and beamcolumn connections， and the safeguard measures of stiffness of the assembled floor are studied．Research achievements have been applied to the pilot project successfully．
The development of industrial prefabricated steel structure especially conforms to the strategic requirement of dissolving excess production capacity，development of green building and ecological civilization construction in China． It is the only way to truly achieve industrialization and modernization for China's construction industry． It also ensures the quality and speed of post-disaster reconstruction and the urgent request of seismic safety． This paper analyzed the current bottleneck of industrialization of industrial prefabricated steel structure in China． The problems of industrial prefabricated steel structure system and innovation of the joint in the new structure system，standard specification establishment，global optimization of steel structure design of prefabricated steel structure system with diagonal bracing at joints，structural overall stability，the mainboard and column stability，severe earthquake elastoplastic analysis，experiment of single cross framework，performance experiment of flange bolt connection and beamcolumn connections， and the safeguard measures of stiffness of the assembled floor are studied．Research achievements have been applied to the pilot project successfully．
2014, 44(08): 7-9.
Abstract:
It was introduced the characteristics and development prospect of prefabricated steel structure residence． The materials of the matching of external wall is classified and compared，and the project examples are presented． The selection principle of material and the structural requirements of external wall joint connection were given． Through the investigation，the problems and recommendations on the matching of external wall for the prefabricated steel structure residence were proposed．
It was introduced the characteristics and development prospect of prefabricated steel structure residence． The materials of the matching of external wall is classified and compared，and the project examples are presented． The selection principle of material and the structural requirements of external wall joint connection were given． Through the investigation，the problems and recommendations on the matching of external wall for the prefabricated steel structure residence were proposed．
2014, 44(08): 10-13.
Abstract:
New Industrial prefabricated steel frame with diagonal brace is consists of steel truss beam，steel column and steel diagonal brace． The truss beam and diagonal brace are different from the traditional one，whose transferring way of force，mechanical behavior and failure mechanism are not examined． The static test and finite element analysis were done for the single span，single cross and single deck steel frame，aims to study the ultimate bearing capacity of horizontal load，deformation characteristics，failure mechanism and ductility performance． The results of test and analysis show that prefabricated brace frame has strong ability to withstand the horizontal load，the power transmission path is clear，and the damage is located at the mid web member of truss beam． While truss beam is damaged，the frame column and the nodes are in elastic state． The frame can meet the structural requirements ofstrong jiont， weak componentsandstrong column，weak beamseismic design requirements．
New Industrial prefabricated steel frame with diagonal brace is consists of steel truss beam，steel column and steel diagonal brace． The truss beam and diagonal brace are different from the traditional one，whose transferring way of force，mechanical behavior and failure mechanism are not examined． The static test and finite element analysis were done for the single span，single cross and single deck steel frame，aims to study the ultimate bearing capacity of horizontal load，deformation characteristics，failure mechanism and ductility performance． The results of test and analysis show that prefabricated brace frame has strong ability to withstand the horizontal load，the power transmission path is clear，and the damage is located at the mid web member of truss beam． While truss beam is damaged，the frame column and the nodes are in elastic state． The frame can meet the structural requirements ofstrong jiont， weak componentsandstrong column，weak beamseismic design requirements．
2014, 44(08): 14-18.
Abstract:
Nonlinear finite element analysis of the steel truss girder in the fabricated steel structure of housing system was studied in this paper． Finite element models of steel truss girders were established with five different spans and different chord sizes． It was compared the load -displacement curves of the analysis results from different girders，the ultimate bearing capacity and deformation characteristic of the steel truss girder in the fabricated steel structure were studied． The plastic zone mainly occurs at midspan chord when the girder damaged，and webs at a relatively small force damaged after the chord，which could meet the design requirements ofstrong shear and weak bending． The big difference between yield load and ultimate load makes the member have certain safety margin space．
Nonlinear finite element analysis of the steel truss girder in the fabricated steel structure of housing system was studied in this paper． Finite element models of steel truss girders were established with five different spans and different chord sizes． It was compared the load -displacement curves of the analysis results from different girders，the ultimate bearing capacity and deformation characteristic of the steel truss girder in the fabricated steel structure were studied． The plastic zone mainly occurs at midspan chord when the girder damaged，and webs at a relatively small force damaged after the chord，which could meet the design requirements ofstrong shear and weak bending． The big difference between yield load and ultimate load makes the member have certain safety margin space．
2014, 44(08): 19-22.
Abstract:
In order to remedy the defects of researches high-level fabricated steel frame system at home and abroad， and provide the basis for the development and design of multi-story industrialized prefabricated steel frame structure system at the same time，the finite element software ANSYS 14. 0 was used to make the static analysis and pseudostatic analysis of prefabricated steel frame taken from the actual project which is single-bay，two-layer and single-span steel frame． The energy dissipation capacity and ductility performance of the frame under low frequency cyclic loading were studied，and the bearing capacity and failure mechanism of the frame were analyzed．Research shows: prefabricated steel frame has good deformation performance，under the earthquake action，at the truss beam end plastic hinge forms to consume energy，the hysteretic curve of prefabricated steel frame is full，showing good plastic deformation and energy dissipation ability．
In order to remedy the defects of researches high-level fabricated steel frame system at home and abroad， and provide the basis for the development and design of multi-story industrialized prefabricated steel frame structure system at the same time，the finite element software ANSYS 14. 0 was used to make the static analysis and pseudostatic analysis of prefabricated steel frame taken from the actual project which is single-bay，two-layer and single-span steel frame． The energy dissipation capacity and ductility performance of the frame under low frequency cyclic loading were studied，and the bearing capacity and failure mechanism of the frame were analyzed．Research shows: prefabricated steel frame has good deformation performance，under the earthquake action，at the truss beam end plastic hinge forms to consume energy，the hysteretic curve of prefabricated steel frame is full，showing good plastic deformation and energy dissipation ability．
2014, 44(08): 23-26.
Abstract:
Welded joints，bolted joints，bolted and welded joints are the typical joints in fabricated high-rise steel structure． The paper established three models of the joints of truss-beam and column for nonlinear analysis using the finite element software ABAQUS，it was got that the failure mechanism， the limit bearing capacity and the energy dissipation capacity that was the one in the function of monotonic cyclic load． The results show that the limit bearing capacity of the welded joint is the highest，but the plastic deformation mainly appears in joint region， so it dissatisfies the seismic request． The slip occurs easily in frictional regions for the bolted joint in the function of monotonic cyclic load． The out-of-plane buckling of the overall truss-beam in bolted and welded joint occurs due to the different stiffness of the two sections of the single beam-truss． So the limit bearing capacity of this joint is the lowest． It was proposed that some suggestions on the design of three typical joints of truss-beam and column in fabricated high-rise steel structure．
Welded joints，bolted joints，bolted and welded joints are the typical joints in fabricated high-rise steel structure． The paper established three models of the joints of truss-beam and column for nonlinear analysis using the finite element software ABAQUS，it was got that the failure mechanism， the limit bearing capacity and the energy dissipation capacity that was the one in the function of monotonic cyclic load． The results show that the limit bearing capacity of the welded joint is the highest，but the plastic deformation mainly appears in joint region， so it dissatisfies the seismic request． The slip occurs easily in frictional regions for the bolted joint in the function of monotonic cyclic load． The out-of-plane buckling of the overall truss-beam in bolted and welded joint occurs due to the different stiffness of the two sections of the single beam-truss． So the limit bearing capacity of this joint is the lowest． It was proposed that some suggestions on the design of three typical joints of truss-beam and column in fabricated high-rise steel structure．
2014, 44(08): 27-34.
Abstract:
In this article， the object of study is a kind of key joint in modular prefabricated high-rise steel structure． Both the finite element analysis and experimental research on the static behaviors were carried out，the limit bearing capacity and the flexural rigidity were studied． The result show that this kind of joint has relatively large rotational stiffness and relatively high limit bearing capacity． The failure mainly caused by the instability of the web member of the truss beam in test，which resulted in the out-of-plane buckling of the whole truss-beam; there is no slip on the high strength bolt connection of the joints．
In this article， the object of study is a kind of key joint in modular prefabricated high-rise steel structure． Both the finite element analysis and experimental research on the static behaviors were carried out，the limit bearing capacity and the flexural rigidity were studied． The result show that this kind of joint has relatively large rotational stiffness and relatively high limit bearing capacity． The failure mainly caused by the instability of the web member of the truss beam in test，which resulted in the out-of-plane buckling of the whole truss-beam; there is no slip on the high strength bolt connection of the joints．
2014, 44(08): 35-38.
Abstract:
For column-beam splice joint with flange-column of fabricated steel structure， the mechanical behavior and connection are very complex， and there are many influencing factors for its strength and rigidity． ANSYS finite element analysis software was used to analyze and simulate the beam-column's joint of the steel framed structure with or without braces． The seism-resisting behavior of the fabricated steel frame beam-column joints including the hysteretic behavior，ultimate bearing capacity，ductility coefficient，failure mode etc． were studied． The results show that for the fabricated steel frame beam-column joints with supports the joint's rigidity and bearing capacity are increased greatly． To bolt connection of beam-column joints with braces，the bearing capacity is improved by more than three times，and to welded joint，it is improved by about 50 percent，ductility factor is increased by about 70 percent． Through setting braces，the plastic hinge is transferred effectively，and the failure locations are located on the truss beam outside of the brace，which has played an important role in protecting the connection，and accorded with the design requirement ofstrong connection，weak component． Meanwhile hysteresis curves display more fully under the cyclic reverse loading，indicating better aseismic performance．
For column-beam splice joint with flange-column of fabricated steel structure， the mechanical behavior and connection are very complex， and there are many influencing factors for its strength and rigidity． ANSYS finite element analysis software was used to analyze and simulate the beam-column's joint of the steel framed structure with or without braces． The seism-resisting behavior of the fabricated steel frame beam-column joints including the hysteretic behavior，ultimate bearing capacity，ductility coefficient，failure mode etc． were studied． The results show that for the fabricated steel frame beam-column joints with supports the joint's rigidity and bearing capacity are increased greatly． To bolt connection of beam-column joints with braces，the bearing capacity is improved by more than three times，and to welded joint，it is improved by about 50 percent，ductility factor is increased by about 70 percent． Through setting braces，the plastic hinge is transferred effectively，and the failure locations are located on the truss beam outside of the brace，which has played an important role in protecting the connection，and accorded with the design requirement ofstrong connection，weak component． Meanwhile hysteresis curves display more fully under the cyclic reverse loading，indicating better aseismic performance．
2014, 44(08): 39-45.
Abstract:
The assembled floor slab that applied in modular assembled high-rise steel structure is a discontinuity slab． As for its assembled slot，assembled slab has an insufficient plane stiffness，which effect its integrity function． To insure the plane stiffness and integrity of assembled slab，three kinds of connectors were designed，i． e． beam connector，slab connector and beam-slab connector． Considering connector types and connector spacing，ABAQUS was used to analyse a failure character of floor slab，bearing capacity，slab slot shear rigidity，stress transmission capacity between slab slot and the slot value of assembled shear slab， to obtain the performance and the force transmission effect of the slab slot． The analysis results show that the connector spacing is the main factor affecting the plane stiffness of assembled slab，just adopting only beam connector cannot control slab slot well，slab connector and beam-slab connector are the effective connections in assembled slab slot． It is suggested that the slab connector spacing and the beam-slab connector spacing should be controlled within 0. 75 m and 1. 0 m respectively．
The assembled floor slab that applied in modular assembled high-rise steel structure is a discontinuity slab． As for its assembled slot，assembled slab has an insufficient plane stiffness，which effect its integrity function． To insure the plane stiffness and integrity of assembled slab，three kinds of connectors were designed，i． e． beam connector，slab connector and beam-slab connector． Considering connector types and connector spacing，ABAQUS was used to analyse a failure character of floor slab，bearing capacity，slab slot shear rigidity，stress transmission capacity between slab slot and the slot value of assembled shear slab， to obtain the performance and the force transmission effect of the slab slot． The analysis results show that the connector spacing is the main factor affecting the plane stiffness of assembled slab，just adopting only beam connector cannot control slab slot well，slab connector and beam-slab connector are the effective connections in assembled slab slot． It is suggested that the slab connector spacing and the beam-slab connector spacing should be controlled within 0. 75 m and 1. 0 m respectively．
2014, 44(08): 46-49.
Abstract:
A new style floor slab by steel truss and foam cement is introduced in this paper． Due to the use of the new light-weight material foam cement，the floor slab has advantage over the traditional steel truss slab with concrete in further light-weight，thermal and sound insulation properties． In this paper，the short-term stiffness of the floor during the construction phase was studied by the effective moment of inertia method，and a formula was presented． The contribution of precast foam cement layer to the stiffness of the floor cross-section was analysed by an example． The result shows that the contribution of the foam cement layer is a small part of 10%，mainly due to the low strength and small elasticity modulus of the foam cement． Therefore，to simplify the calculation and analysis ，the role of prefabricated foam cement layer can be ignored．
A new style floor slab by steel truss and foam cement is introduced in this paper． Due to the use of the new light-weight material foam cement，the floor slab has advantage over the traditional steel truss slab with concrete in further light-weight，thermal and sound insulation properties． In this paper，the short-term stiffness of the floor during the construction phase was studied by the effective moment of inertia method，and a formula was presented． The contribution of precast foam cement layer to the stiffness of the floor cross-section was analysed by an example． The result shows that the contribution of the foam cement layer is a small part of 10%，mainly due to the low strength and small elasticity modulus of the foam cement． Therefore，to simplify the calculation and analysis ，the role of prefabricated foam cement layer can be ignored．
2014, 44(08): 50-54.
Abstract:
There is little literature on the sound fields characteristics of Chinese traditional courtyards so far． Three main courts in Shenyang Palace Museum were chosen as research subjects． Firstly a dodecahedron sound player was placed as a continuous sound source in the courtyard，and the sound pressure level on the adjacent courtyard was tested． It is intended to analyze the sound private degree in Shenyang Palace courtyards． Then the sound cutting method was used to systematically test reverberation time T10 as the important acoustic index in Palace courtyards． The results of this research will be help to understand the sound field characteristics of the ancient palace courtyard and set up a solid foundation for the future study．
There is little literature on the sound fields characteristics of Chinese traditional courtyards so far． Three main courts in Shenyang Palace Museum were chosen as research subjects． Firstly a dodecahedron sound player was placed as a continuous sound source in the courtyard，and the sound pressure level on the adjacent courtyard was tested． It is intended to analyze the sound private degree in Shenyang Palace courtyards． Then the sound cutting method was used to systematically test reverberation time T10 as the important acoustic index in Palace courtyards． The results of this research will be help to understand the sound field characteristics of the ancient palace courtyard and set up a solid foundation for the future study．
2014, 44(08): 55-60.
Abstract:
Based on the structural features of the cold-formed thin-walled steel structure residence，a energy saving environmentally friendly double-layer air circulation system with the respiratory function was developed，and Fluent ＆ Airpak softwores were used to do 3D sumulation to explore the impact mechanism of the system on indoor thermal environment． It was examined various index properties and influencing factors including velocity field，temperature field，PPD-PMV distribution etc，from the various components of the air circulation system during operation Fluent and Airpak，have been examined，whereby to evaluate the indoor airflow and air quality．Research shows that the buffer layer of air can provide good air source for both the inner and outer air layer; the outer layer of air can dynamically isolate indoor and outdoor heat by taking advantage of stack effect; Under the premise of low energy consumption，the utilization of the entire double air circulation system can improve the indoor thermal environment as well as provide 24 － hour fresh air for the indoor occupants，so that the purpose of energy saving and environmental protection could be achieved．
Based on the structural features of the cold-formed thin-walled steel structure residence，a energy saving environmentally friendly double-layer air circulation system with the respiratory function was developed，and Fluent ＆ Airpak softwores were used to do 3D sumulation to explore the impact mechanism of the system on indoor thermal environment． It was examined various index properties and influencing factors including velocity field，temperature field，PPD-PMV distribution etc，from the various components of the air circulation system during operation Fluent and Airpak，have been examined，whereby to evaluate the indoor airflow and air quality．Research shows that the buffer layer of air can provide good air source for both the inner and outer air layer; the outer layer of air can dynamically isolate indoor and outdoor heat by taking advantage of stack effect; Under the premise of low energy consumption，the utilization of the entire double air circulation system can improve the indoor thermal environment as well as provide 24 － hour fresh air for the indoor occupants，so that the purpose of energy saving and environmental protection could be achieved．
2014, 44(08): 61-64.
Abstract:
The underground courtyard in the west of Henan is known asthe underground courtyardin the north． In this paper， through the research on the problems of the local underground courtyard，pointed out the conception on the sustainable construction technology of underground courtyard．
The underground courtyard in the west of Henan is known asthe underground courtyardin the north． In this paper， through the research on the problems of the local underground courtyard，pointed out the conception on the sustainable construction technology of underground courtyard．
2014, 44(08): 65-67.
Abstract:
The image of industrial buildings is gradually changing as the development of the society， and the demands on industrial buildings by people are much higher than the concept ofthe box of machines． Meanwhile，the design of the industrial building is not simple and unitary any more． It was strived to establish advanced，ecological and artistic industrial building according to the diverse functions，surroundings as well as the concern of enterprise cultures． The application of expresion pattern of diversity for industrial building to the first stage project of Laizhou Power Plant of China Huadian Corporation was explored．
The image of industrial buildings is gradually changing as the development of the society， and the demands on industrial buildings by people are much higher than the concept ofthe box of machines． Meanwhile，the design of the industrial building is not simple and unitary any more． It was strived to establish advanced，ecological and artistic industrial building according to the diverse functions，surroundings as well as the concern of enterprise cultures． The application of expresion pattern of diversity for industrial building to the first stage project of Laizhou Power Plant of China Huadian Corporation was explored．
2014, 44(08): 68-70.
Abstract:
In the creation of a cultural building，reasonable interpretation of culture is the priority among priorities． Taking the design scheme of Funan County Cultural Arts Center creation for example，a meeting point was to be found in the deep regional culture and the architectural form; through the refinement of regional culture，the abstract and complex cultural connotation would be embodied by specific architectural form，trying to make a model of culture，let the building show strong regional culture characteristics．
In the creation of a cultural building，reasonable interpretation of culture is the priority among priorities． Taking the design scheme of Funan County Cultural Arts Center creation for example，a meeting point was to be found in the deep regional culture and the architectural form; through the refinement of regional culture，the abstract and complex cultural connotation would be embodied by specific architectural form，trying to make a model of culture，let the building show strong regional culture characteristics．
2014, 44(08): 71-77.
Abstract:
Reversed cyclic loading tests were carried out on 6 reinforced concrete short columns with welded stirrups and 3 comparative reinforced concrete short columns with ordinary stirrups to study the shear properties of reinforced concrete members with welded stirrups． Also，the tests of 5 reinforced concrete beams with welded stirrups and 4 reinforced concrete beams with common stirrups were carried out to study the shear performance of inclined section． The influences of the factors such as the concrete strength，stirrup ratio，axial compression ratio and shear span ratio on the shear bearing capacity of reinforced concrete column and beam with welded stirrups were analyzed，and the differences of the shear bearing capacity between the welded stirrups and ordinary binding stirrups of reinforced concrete column and beam were compared． The results indicate that the damage form is basically the same， and the shear bearing capacity of reinforced concrete column and beam with welded stirrups are higher than the ordinary elements． In addition，the shearing bearing capacity is low，when using the formula in the currentCode of Concrete Structure Design( GB 500102010) ． Therefore，the test data were analysed and the calculation formula of shear bearing capacity for reinforced concrete column and beam with welded stirrups was fitted out in this paper． It is shown that the calculation values are in good agreement with the test results，which can be used for engineering design．
Reversed cyclic loading tests were carried out on 6 reinforced concrete short columns with welded stirrups and 3 comparative reinforced concrete short columns with ordinary stirrups to study the shear properties of reinforced concrete members with welded stirrups． Also，the tests of 5 reinforced concrete beams with welded stirrups and 4 reinforced concrete beams with common stirrups were carried out to study the shear performance of inclined section． The influences of the factors such as the concrete strength，stirrup ratio，axial compression ratio and shear span ratio on the shear bearing capacity of reinforced concrete column and beam with welded stirrups were analyzed，and the differences of the shear bearing capacity between the welded stirrups and ordinary binding stirrups of reinforced concrete column and beam were compared． The results indicate that the damage form is basically the same， and the shear bearing capacity of reinforced concrete column and beam with welded stirrups are higher than the ordinary elements． In addition，the shearing bearing capacity is low，when using the formula in the currentCode of Concrete Structure Design( GB 500102010) ． Therefore，the test data were analysed and the calculation formula of shear bearing capacity for reinforced concrete column and beam with welded stirrups was fitted out in this paper． It is shown that the calculation values are in good agreement with the test results，which can be used for engineering design．
2014, 44(08): 78-83.
Abstract:
Based on bending test of eight high strength reinforced reactive powder concrete simple beams by changing the longitudinal rebar ratio and rebar grade of test beams，it was analyzed the load-bearing properties and deformation characteristics of the test beams． The results showed that with the reinforcement ratio and rebar grade were increased，the bearing capacity and the overall stiffness of the test beams also were increased; slowed the longitudinal reinforcement getting into the plastic stage，restrained the development of cracks effectively，reduced the beam deflection at load stage． According to the forced characteristics of high-strength reinforced reactive powder concrete beams，bending stiffness calculation formulas were set up，through which calculated values agreed well with the experimental values，which provided a reference for design of high strength reinforced reactive powder concrete beam．
Based on bending test of eight high strength reinforced reactive powder concrete simple beams by changing the longitudinal rebar ratio and rebar grade of test beams，it was analyzed the load-bearing properties and deformation characteristics of the test beams． The results showed that with the reinforcement ratio and rebar grade were increased，the bearing capacity and the overall stiffness of the test beams also were increased; slowed the longitudinal reinforcement getting into the plastic stage，restrained the development of cracks effectively，reduced the beam deflection at load stage． According to the forced characteristics of high-strength reinforced reactive powder concrete beams，bending stiffness calculation formulas were set up，through which calculated values agreed well with the experimental values，which provided a reference for design of high strength reinforced reactive powder concrete beam．
2014, 44(08): 84-87.
Abstract:
An experimental study was conducted to evaluate the shear bearing capacity of -shape slab joint connection used in new-type precast concrete floor diaphragm under monotonic and low-cycle loads． Failure process and mode，load-displacement relationship curves，energy dissipation capacity etc of the test specimens were investigated． And the test results showed that the shear bearing capacity of the -shape connection was not ideal because of the weld fracture between anchor bar and steel plate under the said load condition． The hysteretic curves of -shape connection shrank seriously，which showed bad energy dissipation and seismic performance． It is suggested that piercing plug welding should be used to ensure the welding quality between anchor bars and steel plates and to enhance the shear bearing capacity of the -shape slab joints．
An experimental study was conducted to evaluate the shear bearing capacity of -shape slab joint connection used in new-type precast concrete floor diaphragm under monotonic and low-cycle loads． Failure process and mode，load-displacement relationship curves，energy dissipation capacity etc of the test specimens were investigated． And the test results showed that the shear bearing capacity of the -shape connection was not ideal because of the weld fracture between anchor bar and steel plate under the said load condition． The hysteretic curves of -shape connection shrank seriously，which showed bad energy dissipation and seismic performance． It is suggested that piercing plug welding should be used to ensure the welding quality between anchor bars and steel plates and to enhance the shear bearing capacity of the -shape slab joints．
2014, 44(08): 88-91.
Abstract:
The railway bridge piers with low reinforcement ratios are still widely used in our country，which have poor deformation capacity and brittle failure mode under earthquake． In order to improve the seismic performance of such a kind of piers，the idea of using high strength rebar to realize seismic ductility for piers with low reinforcement ratios is put forward． A HRBF500 reinforced pier specimen with low reinforcement ratio was tested under low-cycle loading． The failure mode，hysteretic characteristics，stiffness degradation，energy dissipation and ductility of the specimen were studied． The results indicate that the failure pattern of the specimen is ductile failure． Furthermore，the realization mechanism of seismic ductility by high strength rebar for piers with low reinforcement ratios is further analyzed．
The railway bridge piers with low reinforcement ratios are still widely used in our country，which have poor deformation capacity and brittle failure mode under earthquake． In order to improve the seismic performance of such a kind of piers，the idea of using high strength rebar to realize seismic ductility for piers with low reinforcement ratios is put forward． A HRBF500 reinforced pier specimen with low reinforcement ratio was tested under low-cycle loading． The failure mode，hysteretic characteristics，stiffness degradation，energy dissipation and ductility of the specimen were studied． The results indicate that the failure pattern of the specimen is ductile failure． Furthermore，the realization mechanism of seismic ductility by high strength rebar for piers with low reinforcement ratios is further analyzed．
2014, 44(08): 92-97.
Abstract:
Restricted by the thermal process layout，space layout of the main power house of a power plant is complex and with poor overall performance． A tradition ofRC main powerhouse structure with more weaknesses and low safety stock，its using in high seismic intensity regions is restricted． In this paper，SRC frame-shear wall hybrid structure system was put forward，and a 1 000 MW main powerhouse is taken as a research object，seismic performance test was carried out to study the structural deformation capacity，stiffness degradation rule，failure mode and energy dissipation capacity．Research results show that SRC frame-shear wall hybrid structure has godd seismic and economic erformance; Which can be better used in large-scale thermal power plant in high seismic intensity region．
Restricted by the thermal process layout，space layout of the main power house of a power plant is complex and with poor overall performance． A tradition ofRC main powerhouse structure with more weaknesses and low safety stock，its using in high seismic intensity regions is restricted． In this paper，SRC frame-shear wall hybrid structure system was put forward，and a 1 000 MW main powerhouse is taken as a research object，seismic performance test was carried out to study the structural deformation capacity，stiffness degradation rule，failure mode and energy dissipation capacity．Research results show that SRC frame-shear wall hybrid structure has godd seismic and economic erformance; Which can be better used in large-scale thermal power plant in high seismic intensity region．
2014, 44(08): 98-102.
Abstract:
Buckling-restrained brace ( BRB) is introduced in the reinforced concrete frame-bent structure in order to provide a new solution to large thermal power plants in seismic region of intensity 8． Based on an actual project，a sample design of BRB-frame-bent system was developed considering site condition 2 with seismic intensity 8． Two finite element models with and without BRBs were established with nonlinear analytical software Perform 3D and elasto-plastic time history analyses under rare earthquakes were performed． Analytical results showed that BRBs dissipated a large amount of seismic energy，which would otherwise mostly suffered by columns，and thus the damage to bottom weak floor could be avoided，ensuring the safety of the structure under rare earthquakes and qualifying a superior seismic resistant structural system．
Buckling-restrained brace ( BRB) is introduced in the reinforced concrete frame-bent structure in order to provide a new solution to large thermal power plants in seismic region of intensity 8． Based on an actual project，a sample design of BRB-frame-bent system was developed considering site condition 2 with seismic intensity 8． Two finite element models with and without BRBs were established with nonlinear analytical software Perform 3D and elasto-plastic time history analyses under rare earthquakes were performed． Analytical results showed that BRBs dissipated a large amount of seismic energy，which would otherwise mostly suffered by columns，and thus the damage to bottom weak floor could be avoided，ensuring the safety of the structure under rare earthquakes and qualifying a superior seismic resistant structural system．
2014, 44(08): 103-107.
Abstract:
In Chinese traditional timber structures，the way of stitching is often found in beam and purlin members． For 3-purlin beam and 5-purlin beam members，when their bearing capacity and rigidity are not adequate，they are often strengthened by the ways of stitching of beam-jiaobei or beam-suiliangfang． For purlin members，they are often strengthened by the way of stitching of purlin-suilinfang． The stitching beams are mainly two types which are small top and big bottom type and big top and small bottom type． In order to study the bending behavior including the failure mode and bending bearing capacity and strain distribution at mid-span section of timber stitching beams with small top and big bottom，the bending test on six specimens with traditional conformation were carried out，including three deal specimens and three fir specimens． The results show that the failure modes of this kind of stitching beams are all the brittle breakings of bottoms at lower beams． The distribution of section strain along the height of timber stitching beam basically obeys plane hypothesis． Based on the theoretical analysis and experimental results，the computing formulas of bending bearing capacity of this kind of timber stitching beams made of deal and fir were presented．
In Chinese traditional timber structures，the way of stitching is often found in beam and purlin members． For 3-purlin beam and 5-purlin beam members，when their bearing capacity and rigidity are not adequate，they are often strengthened by the ways of stitching of beam-jiaobei or beam-suiliangfang． For purlin members，they are often strengthened by the way of stitching of purlin-suilinfang． The stitching beams are mainly two types which are small top and big bottom type and big top and small bottom type． In order to study the bending behavior including the failure mode and bending bearing capacity and strain distribution at mid-span section of timber stitching beams with small top and big bottom，the bending test on six specimens with traditional conformation were carried out，including three deal specimens and three fir specimens． The results show that the failure modes of this kind of stitching beams are all the brittle breakings of bottoms at lower beams． The distribution of section strain along the height of timber stitching beam basically obeys plane hypothesis． Based on the theoretical analysis and experimental results，the computing formulas of bending bearing capacity of this kind of timber stitching beams made of deal and fir were presented．
2014, 44(08): 108-113.
Abstract:
Joint plane of rocks have a significant impacts on their physical and mechanical properties． The conventional triaxial compression test of natural phyllite was carried out to research the effect of the included angle between the maximum principal stress，joint plane，and confining pressure on the rock deformation-failure mode． The test results showed: 1) There were three deformation-failure modes with the included angle being in the range of 5 to 45: tension-shear composite failure，shear-slide composite failure across，and along the joint plane，and shear failure only along the joint plane． 2) The peak strength of the rock gradually decreased and the failure mode changed from the composite type to single type with increase of included angle． 3) The deformation and strength parameters of phyllite had obvious angle effect，especially on elastic modulus and cohesion． 4 ) The increase of confining pressure would weaken the mechanical effect of rock joint plane．
Joint plane of rocks have a significant impacts on their physical and mechanical properties． The conventional triaxial compression test of natural phyllite was carried out to research the effect of the included angle between the maximum principal stress，joint plane，and confining pressure on the rock deformation-failure mode． The test results showed: 1) There were three deformation-failure modes with the included angle being in the range of 5 to 45: tension-shear composite failure，shear-slide composite failure across，and along the joint plane，and shear failure only along the joint plane． 2) The peak strength of the rock gradually decreased and the failure mode changed from the composite type to single type with increase of included angle． 3) The deformation and strength parameters of phyllite had obvious angle effect，especially on elastic modulus and cohesion． 4 ) The increase of confining pressure would weaken the mechanical effect of rock joint plane．
2014, 44(08): 114-117.
Abstract:
Based on the gradient theory，a gradient dependent nonlocal friction model was established and used to analyze bolt． By using Mindlin's solution of displacement，a solution of shear stress in the anchorage was derived． The nonlocal effect on the contact surface was revealed and the solution of shear stress of the anchorage section was given． The results were compared with those obtained by the gradient dependent nonlocal friction model and local frication model． Factors affecting the nonlocal friction were discussed． Taking account of the nonlocal friction effects， the shear stress peak value in the anchorage zone was smaller than the one without the consideration．
Based on the gradient theory，a gradient dependent nonlocal friction model was established and used to analyze bolt． By using Mindlin's solution of displacement，a solution of shear stress in the anchorage was derived． The nonlocal effect on the contact surface was revealed and the solution of shear stress of the anchorage section was given． The results were compared with those obtained by the gradient dependent nonlocal friction model and local frication model． Factors affecting the nonlocal friction were discussed． Taking account of the nonlocal friction effects， the shear stress peak value in the anchorage zone was smaller than the one without the consideration．
2014, 44(08): 118-120.
Abstract:
The analysis for simplified vibration computation in Design Code of Dynamic Machine Foundation ( GB 5004096) ，for foundation under reciprocating engines，proved that the computation errors for this method were so obvious that the simplified method should be used carefully in design．
The analysis for simplified vibration computation in Design Code of Dynamic Machine Foundation ( GB 5004096) ，for foundation under reciprocating engines，proved that the computation errors for this method were so obvious that the simplified method should be used carefully in design．
2014, 44(08): 121-125.
Abstract:
It was analyzed the monitoring data of the deep excavation of a subway station in Zhengzhou，such as horizontal displacement of retaining wall，axial force of steel struts，surface settlements，etc． The results show that the excavation to the basement，the maximum horizontal displacement at 2 /3 depth of the pit wall is up to 7. 57 mm． And the monitoring value of the steel support axial force is far smaller than the design value，so the design can be optimized Changes in groundwater level shows that the station construction has not too much impact on the surrounding environment，the biggest bottom uplift value is 13. 8 mm，wall maximum horizontal displacement is 7. 5 mm， maximum surface subsidence is 2. 4 mm，which are far less than alert values，Monitoring data and the analysis show that，the support scheme of foundation pit with underground diaphragm with three-row support support is safe and feasible．
It was analyzed the monitoring data of the deep excavation of a subway station in Zhengzhou，such as horizontal displacement of retaining wall，axial force of steel struts，surface settlements，etc． The results show that the excavation to the basement，the maximum horizontal displacement at 2 /3 depth of the pit wall is up to 7. 57 mm． And the monitoring value of the steel support axial force is far smaller than the design value，so the design can be optimized Changes in groundwater level shows that the station construction has not too much impact on the surrounding environment，the biggest bottom uplift value is 13. 8 mm，wall maximum horizontal displacement is 7. 5 mm， maximum surface subsidence is 2. 4 mm，which are far less than alert values，Monitoring data and the analysis show that，the support scheme of foundation pit with underground diaphragm with three-row support support is safe and feasible．
2014, 44(08): 126-130.
Abstract:
It was carried out that loading tests of polyacrylonitrile fiber ( PANF) ceramsite concrete and polyvinyl alcohol fiber ( PVAF) ceramsite concrete at 20，200 400，600 and 800 ℃ to study the change laws of the compressive ＆ tensile strengths and elastic modulus of the ceramsite concrete with temperatures，which were also compared to the ceramsite concrete without fibers． The test results show that the cubic compressive strength of fiber ceramsite concrete is not significantly improved． However the splitting tensile strength after elevated temperature is improved effectively． PANF can improve the brittle fracture performance of ceramsite concrete at the peak loading． The residual prism compressive strength of PANF ceramsite concrete is also obviously increased when the temperature ranges from 20 ℃ to 600 ℃，and the elastic modulus of the PANF decreases more slowly when the temperature ranges from 20 ℃ to 400 ℃．
It was carried out that loading tests of polyacrylonitrile fiber ( PANF) ceramsite concrete and polyvinyl alcohol fiber ( PVAF) ceramsite concrete at 20，200 400，600 and 800 ℃ to study the change laws of the compressive ＆ tensile strengths and elastic modulus of the ceramsite concrete with temperatures，which were also compared to the ceramsite concrete without fibers． The test results show that the cubic compressive strength of fiber ceramsite concrete is not significantly improved． However the splitting tensile strength after elevated temperature is improved effectively． PANF can improve the brittle fracture performance of ceramsite concrete at the peak loading． The residual prism compressive strength of PANF ceramsite concrete is also obviously increased when the temperature ranges from 20 ℃ to 600 ℃，and the elastic modulus of the PANF decreases more slowly when the temperature ranges from 20 ℃ to 400 ℃．
2014, 44(08): 131-135.
Abstract:
In this study，the C30 and C50 ordinary concretes were prepared with washed dredged sand，and unwashed dredged marine sand． Compared to concrete made with river sand，the resistance to sulfate attack of the above concretes was studied by dry-wet cycle test． The results show that the mass loss of the concrete under sulfate attack is related to the surface deterioration． In terms of the same strength grade，the sulfate attacking resistance of washed dredged sand concrete is better than that of the concrete made with river sand． In addition，the chloride from the unwashed dredged sand affects negatively on the resistance to sulfate attack of concrete．
In this study，the C30 and C50 ordinary concretes were prepared with washed dredged sand，and unwashed dredged marine sand． Compared to concrete made with river sand，the resistance to sulfate attack of the above concretes was studied by dry-wet cycle test． The results show that the mass loss of the concrete under sulfate attack is related to the surface deterioration． In terms of the same strength grade，the sulfate attacking resistance of washed dredged sand concrete is better than that of the concrete made with river sand． In addition，the chloride from the unwashed dredged sand affects negatively on the resistance to sulfate attack of concrete．
2014, 44(08): 136-139.
Abstract:
Chemically planted bar in concrete structure is a new style post-embedding technique，but there are few researches for the planted bar stress status under the dynamic load at present． By combining with the chemical bonding mechanism of planted bars under the static force at home and overseas，experimental study on the planted bars specimen adhesive properties was corried out under low cycle load． The displacement-load，strain-load hysteresis curves and the axial strain and bond stress curves of the planted bars through four concrete specimens bond performance tests under low cycle load were got and analyzed，some relative conclusions of the planted bars adhesive properties under the dynamic load were obtained．
Chemically planted bar in concrete structure is a new style post-embedding technique，but there are few researches for the planted bar stress status under the dynamic load at present． By combining with the chemical bonding mechanism of planted bars under the static force at home and overseas，experimental study on the planted bars specimen adhesive properties was corried out under low cycle load． The displacement-load，strain-load hysteresis curves and the axial strain and bond stress curves of the planted bars through four concrete specimens bond performance tests under low cycle load were got and analyzed，some relative conclusions of the planted bars adhesive properties under the dynamic load were obtained．
2014, 44(08): 140-143.
Abstract:
The structural form of hanging roof trusses by a main trussed arch was used for the steel roof of the sports and culture gymnasium in Beijing Institute of Technology，whose main arch was a circular arch composed of steel tubular trussed，and the roof truss was a curved truss composed of steel tubes． It was expounded the main process of quality control of the steel roof of the gymnasium by means of the quality management in the stages of optimization design，member processing，construction and erection of the steel main arch and steel trusses．
The structural form of hanging roof trusses by a main trussed arch was used for the steel roof of the sports and culture gymnasium in Beijing Institute of Technology，whose main arch was a circular arch composed of steel tubular trussed，and the roof truss was a curved truss composed of steel tubes． It was expounded the main process of quality control of the steel roof of the gymnasium by means of the quality management in the stages of optimization design，member processing，construction and erection of the steel main arch and steel trusses．
2014, 44(08): 144-150.
Abstract:
For the highway tunnel through the existing civil air defense engineering in weak surrounding rock，the smooth-surface millisecond blasting technique of small drilling depth was used，and the blasting vibration effect and its impacts decreased for reasonable arrangement of excavation sequences; combined with the construction monitoring and feedbacks in time，the blasting vibration was controlled effectively by adjusting the blasting parameters and construction process; then the safety of the civil air defense engineering was guaranteed and the highway tunnel passed safely and smoothly through the section of the existing engineering in the meanwhile． The monitoring results show that the tunnel blasting excavation scheme，construction process and blasting control measures are important factors affecting the safety of adjacent existing civil air defense engineering． In the blasting construction for the Ⅳ，Ⅴ class surrounding rock，the difference of main vibration frequency of different direction，energy spectrum distribution and amplitude is significant． The main longitudinal horizontal vibration frequency along the tunnel is in the low frequency band of 0 ～ 20 Hz，and the transversal and vertical vibrations of the main vibration frequency band are more wider ( 0 ～ 200 Hz) ． The power spectrum peak of the former is more than 10 times of the latter． In the process of monitoring，special attention should be paid to the effect of the vibration with the main vibration frequency under 20Hz and the speed greater than 50 mm/s． Changes of subsidence and stress of surrounding rock of civil air defense warehouse floor did not exceed the requirement limits of the specification．
For the highway tunnel through the existing civil air defense engineering in weak surrounding rock，the smooth-surface millisecond blasting technique of small drilling depth was used，and the blasting vibration effect and its impacts decreased for reasonable arrangement of excavation sequences; combined with the construction monitoring and feedbacks in time，the blasting vibration was controlled effectively by adjusting the blasting parameters and construction process; then the safety of the civil air defense engineering was guaranteed and the highway tunnel passed safely and smoothly through the section of the existing engineering in the meanwhile． The monitoring results show that the tunnel blasting excavation scheme，construction process and blasting control measures are important factors affecting the safety of adjacent existing civil air defense engineering． In the blasting construction for the Ⅳ，Ⅴ class surrounding rock，the difference of main vibration frequency of different direction，energy spectrum distribution and amplitude is significant． The main longitudinal horizontal vibration frequency along the tunnel is in the low frequency band of 0 ～ 20 Hz，and the transversal and vertical vibrations of the main vibration frequency band are more wider ( 0 ～ 200 Hz) ． The power spectrum peak of the former is more than 10 times of the latter． In the process of monitoring，special attention should be paid to the effect of the vibration with the main vibration frequency under 20Hz and the speed greater than 50 mm/s． Changes of subsidence and stress of surrounding rock of civil air defense warehouse floor did not exceed the requirement limits of the specification．
2014, 44(08): 151-155.
Abstract:
Based on the experimental study on a lattice steel reinforced concrete frame with special-shaped columns under low cyclic reversed loading，the mechanical process and failure patterns were observed． The load-displacement hysteretic loops and skeleton curves and the load and displacement at different stages were obtained． The seismic behaviors such as inter-story drift ratio，ductility，energy dissipation and stiffness degradation were analyzed． Test results show that the failure mechanism of the structure is the beam-hinged mechanism，and it is a typical strongcolumn and weak-beam structure． The hysteretic loops are plump，and the stiffness degradation is unconspicuous． The ultimate elastic-plastic story drift rotation is larger than the limit value specified by the code，demonstrating the high capacity of collapse resistance． The ductility and energy dissipation of the structure are better than that of the reinforced concrete frame with special-shaped columns．
Based on the experimental study on a lattice steel reinforced concrete frame with special-shaped columns under low cyclic reversed loading，the mechanical process and failure patterns were observed． The load-displacement hysteretic loops and skeleton curves and the load and displacement at different stages were obtained． The seismic behaviors such as inter-story drift ratio，ductility，energy dissipation and stiffness degradation were analyzed． Test results show that the failure mechanism of the structure is the beam-hinged mechanism，and it is a typical strongcolumn and weak-beam structure． The hysteretic loops are plump，and the stiffness degradation is unconspicuous． The ultimate elastic-plastic story drift rotation is larger than the limit value specified by the code，demonstrating the high capacity of collapse resistance． The ductility and energy dissipation of the structure are better than that of the reinforced concrete frame with special-shaped columns．
2014, 44(08): 156-161.
Abstract:
After processed the signals obtained from monitoring system，one theory of condition evaluation was proposed on the basis of a new evaluation parameterindex variation． One new condition grade division method was proposed from approximate statistic distribution of index variation，and as per the concept of confidence degree and confidence interval． Because the monitoring data and the standard of condition grade division were all interval numbers，interval extension evaluation theory was adopted to establish the model of condition evaluation． Set-valued statistics and gravity center based decision theory were introduced to divide weight into subjective weight and objective weight to make calculation． Finally，the main bridge of Caiyuanba Yangtze River Bridge was taken for example to do evaluation and analysis by the monitoring data and the theory，and the result showed that the operation condition of main bridge of Caiyuanba Yangtze Ｒiver Bridge was good，and the result agreed well with the bridges actual condition，so this evaluation method was found to be reasonable and had good project practicability．
After processed the signals obtained from monitoring system，one theory of condition evaluation was proposed on the basis of a new evaluation parameterindex variation． One new condition grade division method was proposed from approximate statistic distribution of index variation，and as per the concept of confidence degree and confidence interval． Because the monitoring data and the standard of condition grade division were all interval numbers，interval extension evaluation theory was adopted to establish the model of condition evaluation． Set-valued statistics and gravity center based decision theory were introduced to divide weight into subjective weight and objective weight to make calculation． Finally，the main bridge of Caiyuanba Yangtze River Bridge was taken for example to do evaluation and analysis by the monitoring data and the theory，and the result showed that the operation condition of main bridge of Caiyuanba Yangtze Ｒiver Bridge was good，and the result agreed well with the bridges actual condition，so this evaluation method was found to be reasonable and had good project practicability．
2014, 44(08): 162-163.
Abstract:
Qingdao World Horticultural Exposition Hotel is built for meeting and greeting World Horticultural Exposition that will be held in 2014 in Qingdao，which includes a theme hotel and service apartments． The design concept of this hotel combines Qingdao German architectural style with the western romantic architecture style and modern architectural style． Whose form is different from general hotels in the past，which is an exploration and development of Qingdao gradually being in line with international standards and caters to their special geographical location and the development prospects．
Qingdao World Horticultural Exposition Hotel is built for meeting and greeting World Horticultural Exposition that will be held in 2014 in Qingdao，which includes a theme hotel and service apartments． The design concept of this hotel combines Qingdao German architectural style with the western romantic architecture style and modern architectural style． Whose form is different from general hotels in the past，which is an exploration and development of Qingdao gradually being in line with international standards and caters to their special geographical location and the development prospects．
2014, 44(08): 164-166.
Abstract:
Fuzzy space as important architecture space design approach，expresses an idea of simple energy-saving strategies in the context of ecological and sustainable development． It was analyzed necessity of introducing the role and function of fuzzy space in community clubhouses． Moreover，it was proposed design strategies for making fuzzy space from the formation of interface and shape construction，shadow and light etc，in order to benefit the related research and design．
Fuzzy space as important architecture space design approach，expresses an idea of simple energy-saving strategies in the context of ecological and sustainable development． It was analyzed necessity of introducing the role and function of fuzzy space in community clubhouses． Moreover，it was proposed design strategies for making fuzzy space from the formation of interface and shape construction，shadow and light etc，in order to benefit the related research and design．
2014, 44(08): 167-170.
Abstract:
The State New Urbanization Plan ( 2014 － 2020) proposes that the promotion of economic and social development，land use and urban master planning i． e． integration of many plans into oneshould be done in same regions where conditions are ripe． It was proposed the concept ofintegrating three plans into one，analyzed the main problems and also explored the promotion ofthree plans into onepath．
The State New Urbanization Plan ( 2014 － 2020) proposes that the promotion of economic and social development，land use and urban master planning i． e． integration of many plans into oneshould be done in same regions where conditions are ripe． It was proposed the concept ofintegrating three plans into one，analyzed the main problems and also explored the promotion ofthree plans into onepath．
2014, 44(08): 171-174.
Abstract:
Taking a two-storey office building in Zhanjiang as the application object，it was studied the importance of a full design and its optimization during the whole project construction． Through Tekla three-dimensional model and node design，detail processing of drawings and material control，Tekla BIMsight collaborative design and collision detection，etc． ，it was provided a proper way to achieve a better quality，a shorter construction period and a lower cost project．
Taking a two-storey office building in Zhanjiang as the application object，it was studied the importance of a full design and its optimization during the whole project construction． Through Tekla three-dimensional model and node design，detail processing of drawings and material control，Tekla BIMsight collaborative design and collision detection，etc． ，it was provided a proper way to achieve a better quality，a shorter construction period and a lower cost project．
