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2004 Vol. 34, No. 9
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2004, 34(9): 1-4.
doi: 10.13204/j.gyjz200409001
Abstract:
The incremental method, at present, is widely used in the process-oriented design of a deep excavation engineering of high-rise building structures. However, there are few studies to discuss the fundamental theoretical basis of this methodology in more general sense.The computational results helpful for design should be dependent on excavation process.The incremental method which can take the excavation process into account is different from that of the conventional design method in which the excavation process is overlooked.Therefore the natures of mathematics and mechanics of the incremental method as well as its effect on engineering design are examined. Meanwhile, the rationality and reasonability of the incremental method are demonstrated through numerical analyses of a specific example.
The incremental method, at present, is widely used in the process-oriented design of a deep excavation engineering of high-rise building structures. However, there are few studies to discuss the fundamental theoretical basis of this methodology in more general sense.The computational results helpful for design should be dependent on excavation process.The incremental method which can take the excavation process into account is different from that of the conventional design method in which the excavation process is overlooked.Therefore the natures of mathematics and mechanics of the incremental method as well as its effect on engineering design are examined. Meanwhile, the rationality and reasonability of the incremental method are demonstrated through numerical analyses of a specific example.
2004, 34(9): 5-7.
doi: 10.13204/j.gyjz200409002
Abstract:
The monitoring results of the internal force and displacement of support structure for a subway deep excavation are analyzed.The prestress loss of the anchor is in the range of 10%～25%, with about 10% increase in the axial force of the anchor during the construction. The axial force of steel prop increases with the increment of the excavation depth. And the value changes with the variety of excavation mode, velocity and dismantlement of the underlying props in order. The horizontal displacement of the retaining pile body is related to the pile depth and supporting condition. The deformation of the earth surface is the largest in the middle and the smaller at the end.
The monitoring results of the internal force and displacement of support structure for a subway deep excavation are analyzed.The prestress loss of the anchor is in the range of 10%～25%, with about 10% increase in the axial force of the anchor during the construction. The axial force of steel prop increases with the increment of the excavation depth. And the value changes with the variety of excavation mode, velocity and dismantlement of the underlying props in order. The horizontal displacement of the retaining pile body is related to the pile depth and supporting condition. The deformation of the earth surface is the largest in the middle and the smaller at the end.
2004, 34(9): 8-11.
doi: 10.13204/j.gyjz200409003
Abstract:
The mechanical response of double row pile under step excavation is studied through numerical simulation and using general international geotechnical analytic software FLAC; and the working character istics of the double row pile retaining system are discussed according to the distance between two rows and the insertion depth of a pile.The study shows that the space effect of a portal frame will be poor if the distance between two rows, s4d (d is the diameter of the pile).When s 8d the space effect of the portal frame is also poor with a tie beam acting as a tie bar. The rational range of the distance between two rows is 4d～8d. The displacement of a pile is decreased and its internal force is increased with increasing the insertion depth of the pile.
The mechanical response of double row pile under step excavation is studied through numerical simulation and using general international geotechnical analytic software FLAC; and the working character istics of the double row pile retaining system are discussed according to the distance between two rows and the insertion depth of a pile.The study shows that the space effect of a portal frame will be poor if the distance between two rows, s4d (d is the diameter of the pile).When s 8d the space effect of the portal frame is also poor with a tie beam acting as a tie bar. The rational range of the distance between two rows is 4d～8d. The displacement of a pile is decreased and its internal force is increased with increasing the insertion depth of the pile.
2004, 34(9): 12-14.
doi: 10.13204/j.gyjz200409004
Abstract:
With the characteristics such as simplification, promptness, decreasing the deformation of soil, increasing the stability of an excavation, leading mini-piles have been widely used for excavations in soft soil. But for the design of soil-nailing retaining wall with leading mini-piles, the role of leading mini-piles in the internal stability of soil-nail retaining wall is always neglected and design theory has been lagged behind engineering practice. Based on the failure pattern of soil-nail retaining wall with leading mini-piles and its calculation method, the program for calculating internal stability of soil-nail retaining wall with leading mini-piles has been designed.The developed program has been verfied effectively by engineering practice.
With the characteristics such as simplification, promptness, decreasing the deformation of soil, increasing the stability of an excavation, leading mini-piles have been widely used for excavations in soft soil. But for the design of soil-nailing retaining wall with leading mini-piles, the role of leading mini-piles in the internal stability of soil-nail retaining wall is always neglected and design theory has been lagged behind engineering practice. Based on the failure pattern of soil-nail retaining wall with leading mini-piles and its calculation method, the program for calculating internal stability of soil-nail retaining wall with leading mini-piles has been designed.The developed program has been verfied effectively by engineering practice.
2004, 34(9): 15-18.
doi: 10.13204/j.gyjz200409005
Abstract:
Horizontal displacement of the wall top of a deep excavation is a dynamic dependent process. During its excavation and construction, a equal intervals dynamic combined prediction model of recent information, in which grey system theory and time series analysis method is adopted, is established on the basis of measured data. With the addition of new deformation datum, the model parameters are continuously modified.The complicated factors influencing the displacement in the model are neglected. The practical displacement prediction of the pit has showed that the error between measure and prediction value is mostly below 5 percent.Under the condition of unstable displacement data, the combined prediction value is superior to that of the single grey model. But with the stable data, the prediction displacement value difference by combined or single model is little. The more prediction step, the more error.
Horizontal displacement of the wall top of a deep excavation is a dynamic dependent process. During its excavation and construction, a equal intervals dynamic combined prediction model of recent information, in which grey system theory and time series analysis method is adopted, is established on the basis of measured data. With the addition of new deformation datum, the model parameters are continuously modified.The complicated factors influencing the displacement in the model are neglected. The practical displacement prediction of the pit has showed that the error between measure and prediction value is mostly below 5 percent.Under the condition of unstable displacement data, the combined prediction value is superior to that of the single grey model. But with the stable data, the prediction displacement value difference by combined or single model is little. The more prediction step, the more error.
2004, 34(9): 19-21,80.
doi: 10.13204/j.gyjz200409006
Abstract:
Because of the complexity of excavation engineering, it is very difficult to predict the displacement of retaining structure and the settlement of ground surface, and information construction is very important for an excavation engineering.A method for predicting displacement of retaining structure based on modified BP algorithm is used. The modified algorithm has higher convergence rate and thus improves the conventional one effectively. It is proved that prediction results agree with the measured ones very well, so displacement prediction by the modified BP algorithm is practicable. Finally, the relation between the displacement of retaining structure and the settlement of ground surface is analyzed.
Because of the complexity of excavation engineering, it is very difficult to predict the displacement of retaining structure and the settlement of ground surface, and information construction is very important for an excavation engineering.A method for predicting displacement of retaining structure based on modified BP algorithm is used. The modified algorithm has higher convergence rate and thus improves the conventional one effectively. It is proved that prediction results agree with the measured ones very well, so displacement prediction by the modified BP algorithm is practicable. Finally, the relation between the displacement of retaining structure and the settlement of ground surface is analyzed.
2004, 34(9): 22-25.
doi: 10.13204/j.gyjz200409007
Abstract:
An artificial neural network is introduced in the light of the complexity, nonlinearity of a deep excavation and the importance of multi-step prediction of its deformation.The defect of multi-step prediction by BP network is analyzed and a multi-step prediction model of an excavation deformation based on recurrent neural networks is also proposed.The reliability and practicability of the multi-step prediction of the excavation deformation by the recurrent neural networks are demonstrated through the multi-step prediction of the deformation of deep excavation in soft soil.It can be widely used for the muti-step prediction in other fields.
An artificial neural network is introduced in the light of the complexity, nonlinearity of a deep excavation and the importance of multi-step prediction of its deformation.The defect of multi-step prediction by BP network is analyzed and a multi-step prediction model of an excavation deformation based on recurrent neural networks is also proposed.The reliability and practicability of the multi-step prediction of the excavation deformation by the recurrent neural networks are demonstrated through the multi-step prediction of the deformation of deep excavation in soft soil.It can be widely used for the muti-step prediction in other fields.
2004, 34(9): 26-29,35.
doi: 10.13204/j.gyjz200409008
Abstract:
The optimizing analysis of bracing system for a deep ex cavation is a quite complex system engineering which relates to many target factors of safety and feasibility, less cost construction, environment protection and project construction etc. A deep excavationcs evaluation target system is established, every target factorcs weight is defined by AHP method and the the fuzzy complex evaluation method is applied to evaluating the superior and inferior degree of the bracing system schemes for the deep excavation and then the optimum scheme is obtained.
The optimizing analysis of bracing system for a deep ex cavation is a quite complex system engineering which relates to many target factors of safety and feasibility, less cost construction, environment protection and project construction etc. A deep excavationcs evaluation target system is established, every target factorcs weight is defined by AHP method and the the fuzzy complex evaluation method is applied to evaluating the superior and inferior degree of the bracing system schemes for the deep excavation and then the optimum scheme is obtained.
2004, 34(9): 30-32.
doi: 10.13204/j.gyjz200409009
Abstract:
It becomes trend to construct ecological campus of college and university. Improving acoustical environment is an important part of ecological campus.The measures for constructing relevant acoustical environment are explored according to its site selection, campus planning, architectural design and soundscape construction to ensure a good acoustical environment in ecological campus.
It becomes trend to construct ecological campus of college and university. Improving acoustical environment is an important part of ecological campus.The measures for constructing relevant acoustical environment are explored according to its site selection, campus planning, architectural design and soundscape construction to ensure a good acoustical environment in ecological campus.
2004, 34(9): 33-35.
doi: 10.13204/j.gyjz200409010
Abstract:
It is described that the development, conceptual characteristics, design principle and standards of an ecological house.The operability of the design key points and technical measures for the ecological house is also explored.
It is described that the development, conceptual characteristics, design principle and standards of an ecological house.The operability of the design key points and technical measures for the ecological house is also explored.
2004, 34(9): 36-39.
doi: 10.13204/j.gyjz200409011
Abstract:
With the railway traffic's speed increasing and urbanization expediting, the problem of railway noise becomes worse and worse. The increasing railway noise in Binjiang Residential Zone is investigated; its harm to people is studied and some means improving acoustical environment in residential zone are also put forward.
With the railway traffic's speed increasing and urbanization expediting, the problem of railway noise becomes worse and worse. The increasing railway noise in Binjiang Residential Zone is investigated; its harm to people is studied and some means improving acoustical environment in residential zone are also put forward.
2004, 34(9): 40-44,63.
doi: 10.13204/j.gyjz200409012
Abstract:
Seismic tests were conducted on a model of typical reinforced concrete tube and steel frame composite structure of tall tower on a shaking table.The dynamic properties, seismic responses and damage features of the model were recorded and analyzed.The behavior of the model subject to earthquakes is discussed and furnishes a test basis for the earthquake resistant model and design theory of this, stell-concrete structure system.
Seismic tests were conducted on a model of typical reinforced concrete tube and steel frame composite structure of tall tower on a shaking table.The dynamic properties, seismic responses and damage features of the model were recorded and analyzed.The behavior of the model subject to earthquakes is discussed and furnishes a test basis for the earthquake resistant model and design theory of this, stell-concrete structure system.
2004, 34(9): 45-46,50.
doi: 10.13204/j.gyjz200409013
Abstract:
Based on the elasto-plastic restoring force model for adding damping and stiffness(ADAS)device suggested in this paper, element stiffness matrix for ADAS device and dynamic analysis method for structures with ADAS devices in spatial member-story model are derived.Elasto-plastic seismic response analysis for structures with ADAS devices is added into the HBTA computer program.Seismic mitigation effect of ADAS device upon structure is shown with an example.
Based on the elasto-plastic restoring force model for adding damping and stiffness(ADAS)device suggested in this paper, element stiffness matrix for ADAS device and dynamic analysis method for structures with ADAS devices in spatial member-story model are derived.Elasto-plastic seismic response analysis for structures with ADAS devices is added into the HBTA computer program.Seismic mitigation effect of ADAS device upon structure is shown with an example.
2004, 34(9): 47-50.
doi: 10.13204/j.gyjz200409014
Abstract:
Based on the reinforced concrete structure design theories, the effect of concrete strength deficiency on the bearing capacity, crack width and structural durability of different sorts of structural members is studied, and some relative measures are also put forward to treat the concrete strength deficiency, which may be used as a basis for the design and construction, and for the reliability appraisal and strengthening reconstruction of reinforced concrete structures.
Based on the reinforced concrete structure design theories, the effect of concrete strength deficiency on the bearing capacity, crack width and structural durability of different sorts of structural members is studied, and some relative measures are also put forward to treat the concrete strength deficiency, which may be used as a basis for the design and construction, and for the reliability appraisal and strengthening reconstruction of reinforced concrete structures.
2004, 34(9): 51-53,69.
doi: 10.13204/j.gyjz200409015
Abstract:
Magnetostricive effect, mechanism of magnetostrictive material, the principle of coupling between magnetic and stress, as well as the use of magnetostrictive effect in identification damage of steel tube are reviewed.Equation of sensing among magnetic field and strictive and stress is deduced.From those aspects, the mechanism of sensing for magnetostrictive material is elaborated and a little foundation theory is provided for the use of the mechanism of magnetostrictive effect in civil engineering in the future.
Magnetostricive effect, mechanism of magnetostrictive material, the principle of coupling between magnetic and stress, as well as the use of magnetostrictive effect in identification damage of steel tube are reviewed.Equation of sensing among magnetic field and strictive and stress is deduced.From those aspects, the mechanism of sensing for magnetostrictive material is elaborated and a little foundation theory is provided for the use of the mechanism of magnetostrictive effect in civil engineering in the future.
2004, 34(9): 54-56.
doi: 10.13204/j.gyjz200409016
Abstract:
Through the experimental study on 6 concrete roof plates with corroded reinforcement and deteriorated concrete, deflection and crack distributions of the roof plates with the different characters of deteriorated concrete and different degrees of corroded reinforcements are analyzed. It provides an experimental basis for appraising the rigidity of roof plates in using.
Through the experimental study on 6 concrete roof plates with corroded reinforcement and deteriorated concrete, deflection and crack distributions of the roof plates with the different characters of deteriorated concrete and different degrees of corroded reinforcements are analyzed. It provides an experimental basis for appraising the rigidity of roof plates in using.
2004, 34(9): 57-60.
doi: 10.13204/j.gyjz200409017
Abstract:
Based on nine experiments on edge joints of steel fiber concrete frame, the failure process and characteristics of the joints are studied, and the mechanism model of double shear-compression zone at joint core for shear capacity calculation is presented. The problem that the stirrups and steel fibers work together at the joints is also discussed.Considering the shear stirrups in SFC frame joints, the portion of shear carried by steel fibers should be reduced. As a result, the shear strength formula for these joints is presented, whose results agree well with the test results.
Based on nine experiments on edge joints of steel fiber concrete frame, the failure process and characteristics of the joints are studied, and the mechanism model of double shear-compression zone at joint core for shear capacity calculation is presented. The problem that the stirrups and steel fibers work together at the joints is also discussed.Considering the shear stirrups in SFC frame joints, the portion of shear carried by steel fibers should be reduced. As a result, the shear strength formula for these joints is presented, whose results agree well with the test results.
2004, 34(9): 61-63.
doi: 10.13204/j.gyjz200409018
Abstract:
By comparing tests of low cyclic reversed loading on four full-size members, the strains of steel plate-sticking reinforced frame beam are analysed and co-working conditions of the steel plate-sticking and reinforced concrete are compared.The integral working coefficient Ф is also given primarily and bending resistance equations are set up.
By comparing tests of low cyclic reversed loading on four full-size members, the strains of steel plate-sticking reinforced frame beam are analysed and co-working conditions of the steel plate-sticking and reinforced concrete are compared.The integral working coefficient Ф is also given primarily and bending resistance equations are set up.
2004, 34(9): 64-65.
doi: 10.13204/j.gyjz200409019
Abstract:
Based on the analysis of industrial buildings, the relationship between architectural art and structural technology is briefly discussed. Through the method of art of structural architecture and art of structure, the concord and unification of structure and architecture are achieved. The architectural creation of the industrial buildings will reflect the spirit of the times and become the herald of new industrial architecture.
Based on the analysis of industrial buildings, the relationship between architectural art and structural technology is briefly discussed. Through the method of art of structural architecture and art of structure, the concord and unification of structure and architecture are achieved. The architectural creation of the industrial buildings will reflect the spirit of the times and become the herald of new industrial architecture.
2004, 34(9): 66-69.
doi: 10.13204/j.gyjz200409020
Abstract:
The principle and implementing steps of the static elastoplastic analysis method for evaluating seismic performance of structures are expounded. Its current research situation both at home and abroad is also reviewed. Finally, the advantages of this method and some problems that should be taken into account during seismic performance evaluation are pointed out.
The principle and implementing steps of the static elastoplastic analysis method for evaluating seismic performance of structures are expounded. Its current research situation both at home and abroad is also reviewed. Finally, the advantages of this method and some problems that should be taken into account during seismic performance evaluation are pointed out.
2004, 34(9): 70-73.
doi: 10.13204/j.gyjz200409021
Abstract:
Based on compared experiment study of 2 spatial steel frame concrete short columns and 1 reinforced concrete short column subjected to ax ial load, as well as that of 4 spatial steel frame concrete short columns subjected to eccentric load, the failure characteristics of space steel frame concrete short column are analyzed, at the same time, its design andcalculation method and configuration are also proposed.
Based on compared experiment study of 2 spatial steel frame concrete short columns and 1 reinforced concrete short column subjected to ax ial load, as well as that of 4 spatial steel frame concrete short columns subjected to eccentric load, the failure characteristics of space steel frame concrete short column are analyzed, at the same time, its design andcalculation method and configuration are also proposed.
2004, 34(9): 74-77,98.
doi: 10.13204/j.gyjz200409022
Abstract:
Taking the sizes of cross sections and the volume of ordinary spherical nodes as design variables and overall cost as objective function, the size optimization design of spatial lattice shell is developed by means of two-level algorithem based on discrete variables.The credible structural analysis programme named Algor(Super SAP93) is combined to accomplish the finite element analysis of mathematical model. In addition, zero-step modification is considered to improve the computational precision. At the end, through two numerical examples, the theories above are tested and verified to be correct. Compared with full stress optimization method, the computational results are satisfactory.
Taking the sizes of cross sections and the volume of ordinary spherical nodes as design variables and overall cost as objective function, the size optimization design of spatial lattice shell is developed by means of two-level algorithem based on discrete variables.The credible structural analysis programme named Algor(Super SAP93) is combined to accomplish the finite element analysis of mathematical model. In addition, zero-step modification is considered to improve the computational precision. At the end, through two numerical examples, the theories above are tested and verified to be correct. Compared with full stress optimization method, the computational results are satisfactory.
2004, 34(9): 78-80.
doi: 10.13204/j.gyjz200409023
Abstract:
Through the design, construction and test of six stainless steel trusses of south curtain wall for multi-storied building of Shanghai Communication Hinge, the prestressed truss applied in point-supported glass curtain wall has been studied.
Through the design, construction and test of six stainless steel trusses of south curtain wall for multi-storied building of Shanghai Communication Hinge, the prestressed truss applied in point-supported glass curtain wall has been studied.
2004, 34(9): 81-83.
doi: 10.13204/j.gyjz200409024
Abstract:
The beam joints of concrete filled steel tuble(CFST) and the forced analysis are the key technique for the study and application of CFST structure. Due to the importance of the constitution and performance under loads of beam joints of CFST column, many experimental studies were carried out. According to a column joint which has steel brackets through tubular core, a nonlinear 3D-FEM is presented in Ansysusing the combined reinforced model and smeared cracking model. Under vertical and symmetrical load case the stress distributions and the mechanism of internal force transmission in the joint are studied. The well-agreement between experimental data and calculated result show that the FEM model accurately revealed the performance of the joint. According to the analyses, some advice is given to improve the joint constitution.
The beam joints of concrete filled steel tuble(CFST) and the forced analysis are the key technique for the study and application of CFST structure. Due to the importance of the constitution and performance under loads of beam joints of CFST column, many experimental studies were carried out. According to a column joint which has steel brackets through tubular core, a nonlinear 3D-FEM is presented in Ansysusing the combined reinforced model and smeared cracking model. Under vertical and symmetrical load case the stress distributions and the mechanism of internal force transmission in the joint are studied. The well-agreement between experimental data and calculated result show that the FEM model accurately revealed the performance of the joint. According to the analyses, some advice is given to improve the joint constitution.
2004, 34(9): 84-86,39.
doi: 10.13204/j.gyjz200409025
Abstract:
It is discussed that the seismic action and wind loads of portal frames. The difference between the calculations of wind loads by the standard(GB 50009-2001) and the specification(CECS 102:2002) is analyzed and compared; the conbination of seismic actions in an area with seismic intensity 7 is also compared with that of other loads. The calculations of wind loads on different conditions are proposed and the solution of whether an aseismic checkout is needed in an area with seismic intensity 7 is also given.
It is discussed that the seismic action and wind loads of portal frames. The difference between the calculations of wind loads by the standard(GB 50009-2001) and the specification(CECS 102:2002) is analyzed and compared; the conbination of seismic actions in an area with seismic intensity 7 is also compared with that of other loads. The calculations of wind loads on different conditions are proposed and the solution of whether an aseismic checkout is needed in an area with seismic intensity 7 is also given.
2004, 34(9): 87-92.
doi: 10.13204/j.gyjz200409026
Abstract:
The general principles of joint design of a membrane structure are introduced; and some typical connections are introduced.Moreover, some types of supporting structures and foundation design are also given with a focus on the design methodology of mast and tension anchors.
The general principles of joint design of a membrane structure are introduced; and some typical connections are introduced.Moreover, some types of supporting structures and foundation design are also given with a focus on the design methodology of mast and tension anchors.
2004, 34(9): 93-94,83.
doi: 10.13204/j.gyjz200409027
Abstract:
The steel-encasing strengthening method is used widely in the field of the structural strengthening, based on the Technical Specification for Strengthening Concrete Structures (CECS 25: 90), the principle and the design method of reinforced concrete column strengthened with steel-encasing is descr ibed. Strengthening model and calculating method of steel-encasing strengthening method of compression member in SEU-DEEP are further given, finally an example is used to show this course in detail.
The steel-encasing strengthening method is used widely in the field of the structural strengthening, based on the Technical Specification for Strengthening Concrete Structures (CECS 25: 90), the principle and the design method of reinforced concrete column strengthened with steel-encasing is descr ibed. Strengthening model and calculating method of steel-encasing strengthening method of compression member in SEU-DEEP are further given, finally an example is used to show this course in detail.
2004, 34(9): 95-98.
doi: 10.13204/j.gyjz200409028
Abstract:
This experimental research concentrates on the effects of fiber reinforced plastic(FRP) as a new material to implement structural reinforcement in improving the strength of eccentrically loaded columns. Two cases of large and small eccentricity are considered. Simply-loading test is conducted on the testing columns of each case,which includes the columns reinforced by 2, 3, 4, and 5 layers of FRP and the column without reinforcement.The analysis of testing results provides a testing and theoretical basis for actual usage of FRP reinfor cement.
This experimental research concentrates on the effects of fiber reinforced plastic(FRP) as a new material to implement structural reinforcement in improving the strength of eccentrically loaded columns. Two cases of large and small eccentricity are considered. Simply-loading test is conducted on the testing columns of each case,which includes the columns reinforced by 2, 3, 4, and 5 layers of FRP and the column without reinforcement.The analysis of testing results provides a testing and theoretical basis for actual usage of FRP reinfor cement.
