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2008 Vol. 38, No. 1
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2008, 38(1): 1-3,13.
doi: 10.13204/j.gyjz200801001
Abstract:
Damage-reduction seismic design is a practical design method of performance-based seismic design. According to damage mode of multi-ribbed slab structure which releases earthquake energy by stages, block-frame-outer frame, damagereduction design theory is applied to structure seismic design. It is illustrated that damage-reduction seismic design model and three-stage damage-reduction design of multi-ribbed slab structure. Block which acts as damage-reduction member is served as first damage-reduction fortification line, frame which acts as damage-reduction minor structure is served as second fortification line, and outer frame and reinforced measure are served as third fortification line.
Damage-reduction seismic design is a practical design method of performance-based seismic design. According to damage mode of multi-ribbed slab structure which releases earthquake energy by stages, block-frame-outer frame, damagereduction design theory is applied to structure seismic design. It is illustrated that damage-reduction seismic design model and three-stage damage-reduction design of multi-ribbed slab structure. Block which acts as damage-reduction member is served as first damage-reduction fortification line, frame which acts as damage-reduction minor structure is served as second fortification line, and outer frame and reinforced measure are served as third fortification line.
2008, 38(1): 4-8,23.
doi: 10.13204/j.gyjz200801002
Abstract:
A multi-ribbed composite wall is the main bearing member of a new structural systemmulti-ribbed slab structure. According to the results of previous studying, the elastic simplified mathematical model of the multi-ribbed composite wall is studied. Based on the experimental research on the frame grid elements of the wall. It is discussed the influence of the main factors on the mechanical behaviors and failure modes of the frame grid elements, such as the rigidity of beams and columns in frames, the mechanical properties of filling materials and others. The oblique compression bar which diagonally articulates with reinforced concrete frame is adopted to simulate the action of filler block on the whole wall, and that the width formula of the equivalent oblique compression bar is obtained by analyzing and constructing. On this basis the rigid frame-oblique compression bar. s simplified mathematical model which is suitable for the multi-ribbed composite wall is established. Furthermore the elastic lateral stiffness formula of the rigid frame-oblique compression bar is deduced. Theoretical analysis shows that the rigid frame-oblique compression bar can better reflect the real mechanical behavior of the multi-ribbed composite wall and is a kind of reasonable simplified mathematical model.
A multi-ribbed composite wall is the main bearing member of a new structural systemmulti-ribbed slab structure. According to the results of previous studying, the elastic simplified mathematical model of the multi-ribbed composite wall is studied. Based on the experimental research on the frame grid elements of the wall. It is discussed the influence of the main factors on the mechanical behaviors and failure modes of the frame grid elements, such as the rigidity of beams and columns in frames, the mechanical properties of filling materials and others. The oblique compression bar which diagonally articulates with reinforced concrete frame is adopted to simulate the action of filler block on the whole wall, and that the width formula of the equivalent oblique compression bar is obtained by analyzing and constructing. On this basis the rigid frame-oblique compression bar. s simplified mathematical model which is suitable for the multi-ribbed composite wall is established. Furthermore the elastic lateral stiffness formula of the rigid frame-oblique compression bar is deduced. Theoretical analysis shows that the rigid frame-oblique compression bar can better reflect the real mechanical behavior of the multi-ribbed composite wall and is a kind of reasonable simplified mathematical model.
NONLINEAR NUMERICAL ANALYSIS OF INFLUENCE OF FILLED-BLOCK ON BEHAVIOR OF MULTI-RIBBED COMPOSITE WALL
2008, 38(1): 9-13.
doi: 10.13204/j.gyjz200801003
Abstract:
Using finite element software ANSYS, adopting two types of multi-ribbed composite walls with and without filledblock as analysis objects, that are with 1P2 scale, bottom two stories considering different shearing-span ratio, lateral stiffness, bearing capacity, sectional stress and strain distribution of the walls under horizontal and vertical load were analyzed with nonlinear numer ical method. The quantizing results of contribution of the filled-block for lateral stiffness and compression-bending bearing capacity of thewall were obtained. The effects of the filled-block for increasing lateral stiffness and changing compression-bending failure form of the wall were summed. The analysis results indicated that contribution of aerated concrete filled-block for lateral stiffness of the wall was larger than that for compression-bending bearing capacity, and compression-bending failure form of the wall were influenced by the filled-block, which provide support for establishing simplified calculation method of compression-bending capacity of the multi-ribbed composite wall.
Using finite element software ANSYS, adopting two types of multi-ribbed composite walls with and without filledblock as analysis objects, that are with 1P2 scale, bottom two stories considering different shearing-span ratio, lateral stiffness, bearing capacity, sectional stress and strain distribution of the walls under horizontal and vertical load were analyzed with nonlinear numer ical method. The quantizing results of contribution of the filled-block for lateral stiffness and compression-bending bearing capacity of thewall were obtained. The effects of the filled-block for increasing lateral stiffness and changing compression-bending failure form of the wall were summed. The analysis results indicated that contribution of aerated concrete filled-block for lateral stiffness of the wall was larger than that for compression-bending bearing capacity, and compression-bending failure form of the wall were influenced by the filled-block, which provide support for establishing simplified calculation method of compression-bending capacity of the multi-ribbed composite wall.
2008, 38(1): 14-18.
doi: 10.13204/j.gyjz200801004
Abstract:
Based on elastic foundation beam theory, a mechanical model is suggested for multi-ribbed slab structure under ax ial compression, and solving methods of the model are g iven. It is analyzed the various factors of influencing the bearing of components in structure, which are compared with experimental results. Results of the theory analysis and experiment show that the mechanical model is suitable for analyzing multi-ribbed slab structure under compression, and the calculation result is very exact. The mechanical model provides an important theory foundation for more development of compression and shear capability analysis of multi-ribbed slab structure. the proportion of components bearing vertical loads relate to side frame beam stiffness, rib space and side frame column stiffness, and the most influence factors are side frame beam stiffness and rib space.
Based on elastic foundation beam theory, a mechanical model is suggested for multi-ribbed slab structure under ax ial compression, and solving methods of the model are g iven. It is analyzed the various factors of influencing the bearing of components in structure, which are compared with experimental results. Results of the theory analysis and experiment show that the mechanical model is suitable for analyzing multi-ribbed slab structure under compression, and the calculation result is very exact. The mechanical model provides an important theory foundation for more development of compression and shear capability analysis of multi-ribbed slab structure. the proportion of components bearing vertical loads relate to side frame beam stiffness, rib space and side frame column stiffness, and the most influence factors are side frame beam stiffness and rib space.
2008, 38(1): 19-23.
doi: 10.13204/j.gyjz200801005
Abstract:
Based on the experimental study on different scaled models of the frame-supported multi-ribbed slab wall beam under monotonously vertical load, it is discussed the mechanical behavior of the wall beam under vertical load. Moreover, the main factors affecting the internal force distribution are studied by means of finite element analysis. According to the theory of elastic foundation beam and quoting the trigonometric series analysis, the internal force calculation formula of the frame-supported multi-ribbed wall beam is put forward, and the internal force correction coefficient in the formula is obtained by regression analysis at the same time. Theoretical analysis and experimental results show that there has strong combination action between the trimmer beam and multi-ribbed composite wall, and the results calculated by the practical internal force calculation formula can be closer to the experimental values.
Based on the experimental study on different scaled models of the frame-supported multi-ribbed slab wall beam under monotonously vertical load, it is discussed the mechanical behavior of the wall beam under vertical load. Moreover, the main factors affecting the internal force distribution are studied by means of finite element analysis. According to the theory of elastic foundation beam and quoting the trigonometric series analysis, the internal force calculation formula of the frame-supported multi-ribbed wall beam is put forward, and the internal force correction coefficient in the formula is obtained by regression analysis at the same time. Theoretical analysis and experimental results show that there has strong combination action between the trimmer beam and multi-ribbed composite wall, and the results calculated by the practical internal force calculation formula can be closer to the experimental values.
2008, 38(1): 24-27,35.
doi: 10.13204/j.gyjz200801006
Abstract:
Multi-ribbed slab structure (MRSS) is a new structural system developed in recent years, with multi-ribbed slab wall as its main bearing member. Analysis of the multi-ribbed slab wall on the elastic stage by means of composite material theory is made. Based on the ESCM and the IDD methods, an equivalent elastic slab model adapted to multi-ribbed slab wall is established, and in-plane effective shear moduli of orthotropic equivalent elastic slab is deduced. By testing the model and analyzing experimental data, the composite material equivalent elastic slab model is feasible.
Multi-ribbed slab structure (MRSS) is a new structural system developed in recent years, with multi-ribbed slab wall as its main bearing member. Analysis of the multi-ribbed slab wall on the elastic stage by means of composite material theory is made. Based on the ESCM and the IDD methods, an equivalent elastic slab model adapted to multi-ribbed slab wall is established, and in-plane effective shear moduli of orthotropic equivalent elastic slab is deduced. By testing the model and analyzing experimental data, the composite material equivalent elastic slab model is feasible.
2008, 38(1): 28-30,53.
doi: 10.13204/j.gyjz200801007
Abstract:
Based on previous experimental researches, the twin shear unified strength theory is adopted, in which the influence of intermediate principal stress R2 is considered, and it is applied to various materials of different performance in tension and compression under complex stress state. The reason that the bearing capacity under ax ial compression is enhanced is analyzed, and the formula of bearing capacity under axial compression that had been established is modified. Research results show that, comparing the calculated values of the formula for bearing capacity under ax ial compression based on the twin shear unified strength theory and the values of the previous formula, the former are more closed to the experimental values, and can provide more accurate and economic results for practical engineering; the unified strength theory can be well applied to the theoretical calculation in multi-ribbed slab structure.
Based on previous experimental researches, the twin shear unified strength theory is adopted, in which the influence of intermediate principal stress R2 is considered, and it is applied to various materials of different performance in tension and compression under complex stress state. The reason that the bearing capacity under ax ial compression is enhanced is analyzed, and the formula of bearing capacity under axial compression that had been established is modified. Research results show that, comparing the calculated values of the formula for bearing capacity under ax ial compression based on the twin shear unified strength theory and the values of the previous formula, the former are more closed to the experimental values, and can provide more accurate and economic results for practical engineering; the unified strength theory can be well applied to the theoretical calculation in multi-ribbed slab structure.
2008, 38(1): 31-35.
doi: 10.13204/j.gyjz200801008
Abstract:
Outer-horizontal walls of multi-ribbed slab structure are composed of composite-double wall, based on the previous studies of the subject, and by researching on the test of a 1scaled multi-ribbed composite-double wall under monotone horizontal loading in contrast with single wall, the follovings are done: studying the main failure patterns; discussing the mechanical behaviors such as bearing capacity, stiffeners, distortion capacity, ductility and so on; analyzing the strain; finally, the formulas of rigidity and shear-bearing capacity are deduced. It can be concluded as follow: the distortion capacity and ductility of the double wall are better than those of the single wall, and the stiffeners and shear-bearing capacity of the double wall are more than those of the single wall also; strain analysis shows that the ending columns and ribbed beams play a more important role in the double wall with; the value of the shear-bearing capacity formula and stiffeners formula are approximate to the experimental result, and can be applied to the practical engineering.
Outer-horizontal walls of multi-ribbed slab structure are composed of composite-double wall, based on the previous studies of the subject, and by researching on the test of a 1scaled multi-ribbed composite-double wall under monotone horizontal loading in contrast with single wall, the follovings are done: studying the main failure patterns; discussing the mechanical behaviors such as bearing capacity, stiffeners, distortion capacity, ductility and so on; analyzing the strain; finally, the formulas of rigidity and shear-bearing capacity are deduced. It can be concluded as follow: the distortion capacity and ductility of the double wall are better than those of the single wall, and the stiffeners and shear-bearing capacity of the double wall are more than those of the single wall also; strain analysis shows that the ending columns and ribbed beams play a more important role in the double wall with; the value of the shear-bearing capacity formula and stiffeners formula are approximate to the experimental result, and can be applied to the practical engineering.
2008, 38(1): 36-39,44.
doi: 10.13204/j.gyjz200801009
Abstract:
An elastoplastic macro-model is presented for multi-ribbed compositewalls with shear deformation. The model is composed of three vertical line elements to simulate the composite slab and end columns respectively. The model is based on the finite element but with much less degrees of freedom. When the Link element in SAP 2000 is used to establish model, the element stiffness matrix of link element is deduced. A defining method is developed to determine the location of the shear spring. Combined with hysteretic axial model of reinforced concrete columns and hysteretic shear model of composite walls, the calculating formula for force-displacement relationship of plastic hinges in link element is derived. By using this model, nonlinear analysis of the wall is performed. Comparing with the experimental results, it shows that the model is characterized by clearness in principle, preferable calculating precision. It's suitable for nonlinear time-history analysis of multi-ribbed slab structure.
An elastoplastic macro-model is presented for multi-ribbed compositewalls with shear deformation. The model is composed of three vertical line elements to simulate the composite slab and end columns respectively. The model is based on the finite element but with much less degrees of freedom. When the Link element in SAP 2000 is used to establish model, the element stiffness matrix of link element is deduced. A defining method is developed to determine the location of the shear spring. Combined with hysteretic axial model of reinforced concrete columns and hysteretic shear model of composite walls, the calculating formula for force-displacement relationship of plastic hinges in link element is derived. By using this model, nonlinear analysis of the wall is performed. Comparing with the experimental results, it shows that the model is characterized by clearness in principle, preferable calculating precision. It's suitable for nonlinear time-history analysis of multi-ribbed slab structure.
2008, 38(1): 40-44.
doi: 10.13204/j.gyjz200801010
Abstract:
In the production process of multi-ribbed composite wall, cracks will occur on the contact interface between RC ribbed-frame and AAC blocks under temperature action because of the large difference of material property between concrete and AAC. To discuss the mechanism of the thermal crack of MRCW, the 3D FEM is adopted to simulate temperature field transformation and the analysis of thermal stress is carried out. The relationship between thermal stress and temperature field transformation is presented. The results show that the FE model in this paper accords with engineering practices, and dramatic temperature-decline is the primary reason of increasing abruptly tension stress on surface. The component surface is highly sensitive to any temperature changes. And the temperature gradient of the surface is higher than that of the inner of the component. So, the weakness part is at the component surface. It is suggested that a gap should be set on the contact interface, which would effectively avoid the crack caused by thermal stresses.
In the production process of multi-ribbed composite wall, cracks will occur on the contact interface between RC ribbed-frame and AAC blocks under temperature action because of the large difference of material property between concrete and AAC. To discuss the mechanism of the thermal crack of MRCW, the 3D FEM is adopted to simulate temperature field transformation and the analysis of thermal stress is carried out. The relationship between thermal stress and temperature field transformation is presented. The results show that the FE model in this paper accords with engineering practices, and dramatic temperature-decline is the primary reason of increasing abruptly tension stress on surface. The component surface is highly sensitive to any temperature changes. And the temperature gradient of the surface is higher than that of the inner of the component. So, the weakness part is at the component surface. It is suggested that a gap should be set on the contact interface, which would effectively avoid the crack caused by thermal stresses.
2008, 38(1): 45-49.
doi: 10.13204/j.gyjz200801011
Abstract:
Starting from the concept of the industrial culture and landscape, it is introduced that the background and achievement of research in the field. There are two parts in the article, which are the renewal of old industrial landscape and the construction of new industrial landscape. It is shown that some basic design skills and construction model, which will provide experience and guidance for Chinese construction of industrial landscape.
Starting from the concept of the industrial culture and landscape, it is introduced that the background and achievement of research in the field. There are two parts in the article, which are the renewal of old industrial landscape and the construction of new industrial landscape. It is shown that some basic design skills and construction model, which will provide experience and guidance for Chinese construction of industrial landscape.
2008, 38(1): 50-53.
doi: 10.13204/j.gyjz200801012
Abstract:
It is analyzed that the motivations and significance of the industrial building heritagecs adaptive reuse. Based on reviewing development course of the industrial building heritagecs adaptive reuse, it is summarized that the adaptive reusecs principle and methods. And it is also discussed the characteristics, main trends and lessons on the renovation and adaptive reuse of the West Europe citiesc industrial building heritage by case studies of Winterthur, Vienna and so on. It is finally analyzed and compared the difference in this field of West Europe with China in order to study the advanced methods and expericences.
It is analyzed that the motivations and significance of the industrial building heritagecs adaptive reuse. Based on reviewing development course of the industrial building heritagecs adaptive reuse, it is summarized that the adaptive reusecs principle and methods. And it is also discussed the characteristics, main trends and lessons on the renovation and adaptive reuse of the West Europe citiesc industrial building heritage by case studies of Winterthur, Vienna and so on. It is finally analyzed and compared the difference in this field of West Europe with China in order to study the advanced methods and expericences.
2008, 38(1): 54-57.
doi: 10.13204/j.gyjz200801013
Abstract:
In the cultural heritage of architecture, the railway stations always are the eyewitness to the architectural technique and history of the country, which have the unique position in the history. The railway stations are one of heritages which need protection. However, either in China or in Europe and America, the railway stations have been left to deteriorate. Canada has realized that they should protect the railway stations which have been survived firstly; for one thing, the railway development had affected the national economy enormously; for another thing, it shows Canada values the history which maybe not too far. The research on viewpoint to heritage stations which is based on practice, history and environment in Canada and the protective means, can benefit the protection of cultural heritage in China.
In the cultural heritage of architecture, the railway stations always are the eyewitness to the architectural technique and history of the country, which have the unique position in the history. The railway stations are one of heritages which need protection. However, either in China or in Europe and America, the railway stations have been left to deteriorate. Canada has realized that they should protect the railway stations which have been survived firstly; for one thing, the railway development had affected the national economy enormously; for another thing, it shows Canada values the history which maybe not too far. The research on viewpoint to heritage stations which is based on practice, history and environment in Canada and the protective means, can benefit the protection of cultural heritage in China.
2008, 38(1): 58-59.
doi: 10.13204/j.gyjz200801014
Abstract:
In the urbanized advancement, in many urban environments of our country, one large quantities of old buildings that still have the retention value but they are the cultural relic inheritance, which are being or are going to be demolished. Protection and reusing of the abandoned buildings are an urgent and important task.
In the urbanized advancement, in many urban environments of our country, one large quantities of old buildings that still have the retention value but they are the cultural relic inheritance, which are being or are going to be demolished. Protection and reusing of the abandoned buildings are an urgent and important task.
2008, 38(1): 60-64,73.
doi: 10.13204/j.gyjz200801015
Abstract:
Because of small settlement of end-bearing pile, the bearing capacity of soils among piles can not be carried out, even if the space between piles increased. Consequently, all loads of the super-structure should be supported by piles only. The bearing capacity of soils could not be used, and huge waste caused. A kind of tailored-made equipment named deformation adjustor is studied, which are used to adjust the deformation between the end-bearing pile and the soil among piles. The design method of end-bearing composite pile foundation is presented, in which the end-bearing piles and the soil foundation are working together, especially, the soil plays a main role. The design method has been shown to be reliable.
Because of small settlement of end-bearing pile, the bearing capacity of soils among piles can not be carried out, even if the space between piles increased. Consequently, all loads of the super-structure should be supported by piles only. The bearing capacity of soils could not be used, and huge waste caused. A kind of tailored-made equipment named deformation adjustor is studied, which are used to adjust the deformation between the end-bearing pile and the soil among piles. The design method of end-bearing composite pile foundation is presented, in which the end-bearing piles and the soil foundation are working together, especially, the soil plays a main role. The design method has been shown to be reliable.
2008, 38(1): 65-68,122.
doi: 10.13204/j.gyjz200801016
Abstract:
Based on the displacement model and the characters of numerical manifold method, the cover displacement function, the strain matr ix and the stiffness matrix in manifold element of moderately thick plate are derived for plate bending problems analysis. The controlling equation ofMindlin plate manifold element on Winkler elastic foundation is achieved. The calculation result shows the validity of the plate bending analysis of elastic foundation.
Based on the displacement model and the characters of numerical manifold method, the cover displacement function, the strain matr ix and the stiffness matrix in manifold element of moderately thick plate are derived for plate bending problems analysis. The controlling equation ofMindlin plate manifold element on Winkler elastic foundation is achieved. The calculation result shows the validity of the plate bending analysis of elastic foundation.
2008, 38(1): 69-73.
doi: 10.13204/j.gyjz200801017
Abstract:
According to the theory based on sem-i infinite homogeneous isotropic elastic body, the coefficient of elastic uniform compression changes in inverse proportion to the square root of base area. However, the theoritical conclussion disagrees with a number of results of tests. The paper demonstrates the essential reason causing the disagreement. The paper considers that assuming soils in range of sem-i infinite to be a homogeneous isotropic elastic body is not in accord with practice. In fact, the elastic modulus of soils changes with depth. After considering the factor, the variation rate of coefficient Cz with base area F will be much lower than that with F. This conclusion is demonstrated by a number of computational results. Meanwhile, the paper indicates that the determination of value of Cz for layered soil structure characterized by different mechanical properties, adopted by/Code for Design of Dynamic Machine Foundation0 (GB50040 -96) is unreasonable.
According to the theory based on sem-i infinite homogeneous isotropic elastic body, the coefficient of elastic uniform compression changes in inverse proportion to the square root of base area. However, the theoritical conclussion disagrees with a number of results of tests. The paper demonstrates the essential reason causing the disagreement. The paper considers that assuming soils in range of sem-i infinite to be a homogeneous isotropic elastic body is not in accord with practice. In fact, the elastic modulus of soils changes with depth. After considering the factor, the variation rate of coefficient Cz with base area F will be much lower than that with F. This conclusion is demonstrated by a number of computational results. Meanwhile, the paper indicates that the determination of value of Cz for layered soil structure characterized by different mechanical properties, adopted by/Code for Design of Dynamic Machine Foundation0 (GB50040 -96) is unreasonable.
2008, 38(1): 74-75,109.
doi: 10.13204/j.gyjz200801018
Abstract:
Based on model tests of one equal section steel pile and three tapered steel piles with different side obliquity pressed into clay, the compacting effects of equal section pile and tapered pile in clay ground are studied. The laws of ground heave chang ing with depth during the process of static piling in clay, the location and the value of the max imal ground heave are obtained. The testing results of static piling equal section pile or tapered pile with different side obliquity are also compared and analyzed.
Based on model tests of one equal section steel pile and three tapered steel piles with different side obliquity pressed into clay, the compacting effects of equal section pile and tapered pile in clay ground are studied. The laws of ground heave chang ing with depth during the process of static piling in clay, the location and the value of the max imal ground heave are obtained. The testing results of static piling equal section pile or tapered pile with different side obliquity are also compared and analyzed.
2008, 38(1): 76-80.
doi: 10.13204/j.gyjz200801019
Abstract:
Through the punching shear experiments of 6 blocks of steel fiber reinforced high-strength concrete square slabs with the size of 1 800mm @ 1 800mm@ 150mm, the effect of the concrete intensity and the steel fiber volume on the loaddeflection curve are investigated. The results indicate that the deformation of a slab prior to punching shear failure is mainly bending deformation and the mixture of steel fiber hightens the first crack load, rigidity, ductility and limit bearing capacity of reinforced concrete slab. Based on the experiment results, it is introduced the reduction coefficient of rigidity to inflect the effect of steel fiber on deflection varation and it is set up the related formula of load and deflection which is applied to the whole process from loading to destructing.
Through the punching shear experiments of 6 blocks of steel fiber reinforced high-strength concrete square slabs with the size of 1 800mm @ 1 800mm@ 150mm, the effect of the concrete intensity and the steel fiber volume on the loaddeflection curve are investigated. The results indicate that the deformation of a slab prior to punching shear failure is mainly bending deformation and the mixture of steel fiber hightens the first crack load, rigidity, ductility and limit bearing capacity of reinforced concrete slab. Based on the experiment results, it is introduced the reduction coefficient of rigidity to inflect the effect of steel fiber on deflection varation and it is set up the related formula of load and deflection which is applied to the whole process from loading to destructing.
2008, 38(1): 81-83,113.
doi: 10.13204/j.gyjz200801020
Abstract:
Steel fiber reinforced lightweight aggregate concrete has the virtues of both the steel fiber reinforced concrete and lightweight aggregate(haydite ) concrete, and makes up the deficiencies of common concrete such as low tensile strength and large sel-f weight. By studying the fundamental mechanical properties of the new concrete material, the influence on steel fiber reinforced lightweight aggregate concrete caused by the change of volume ratio of steel fiber was analyzed. The experimental results indicated that after using lightweight aggregate concrete and adding steel fiber, the performance of intensity and deformation of the concrete is greatly improved.
Steel fiber reinforced lightweight aggregate concrete has the virtues of both the steel fiber reinforced concrete and lightweight aggregate(haydite ) concrete, and makes up the deficiencies of common concrete such as low tensile strength and large sel-f weight. By studying the fundamental mechanical properties of the new concrete material, the influence on steel fiber reinforced lightweight aggregate concrete caused by the change of volume ratio of steel fiber was analyzed. The experimental results indicated that after using lightweight aggregate concrete and adding steel fiber, the performance of intensity and deformation of the concrete is greatly improved.
2008, 38(1): 84-87,95.
doi: 10.13204/j.gyjz200801021
Abstract:
It is mainly studied the tensile strength of common concrete which is composed of three coarse aggregatesoriginal state gravel, crushed gravel and limestone rubble. The test results show that the uniax ial direct pulling strength of concrete is about 39% ～48% of resistance to bending and pulling strength, but the two-way tensile strength is about 20%～30%, which is lower than its uniaxial tensile strength, showing obviously bidirectional tensile strength weakening effect. For the structure design of common concrete road board which is under the comprehensive action of car load stress and temperature stress, it. s an important problem deserving of deep study.
It is mainly studied the tensile strength of common concrete which is composed of three coarse aggregatesoriginal state gravel, crushed gravel and limestone rubble. The test results show that the uniax ial direct pulling strength of concrete is about 39% ～48% of resistance to bending and pulling strength, but the two-way tensile strength is about 20%～30%, which is lower than its uniaxial tensile strength, showing obviously bidirectional tensile strength weakening effect. For the structure design of common concrete road board which is under the comprehensive action of car load stress and temperature stress, it. s an important problem deserving of deep study.
2008, 38(1): 88-91.
doi: 10.13204/j.gyjz200801022
Abstract:
A new style of composite column(the column of concrete filled prefabricated tubular members) and cas-t in-place concrete column are studied in this paper, whose main parameters are stirrup ratio and concrete strength of the prefabricated tubular members. According to the analysis of the stress state of the prefabricated tubular members with the biax ial strength criterion of concrete under axial pressure, a formula is presented for general calculation of the cracking load. And according to the experimental data, the formula of ultimate axial compressive strength of the column of concrete filled prefabricated tubular members is obtained.
A new style of composite column(the column of concrete filled prefabricated tubular members) and cas-t in-place concrete column are studied in this paper, whose main parameters are stirrup ratio and concrete strength of the prefabricated tubular members. According to the analysis of the stress state of the prefabricated tubular members with the biax ial strength criterion of concrete under axial pressure, a formula is presented for general calculation of the cracking load. And according to the experimental data, the formula of ultimate axial compressive strength of the column of concrete filled prefabricated tubular members is obtained.
2008, 38(1): 92-95.
doi: 10.13204/j.gyjz200801023
Abstract:
It is introduced a new kind of beam string structure with adjustment of the dog-bone type. First it carries on a study on the conjunction methods of strut bar and cable and according to the problem that strut bar. s vertical accuracy can. t be ensured under construction of beam string, it is put forward a settling method that adopted the adjustment of the dog-bone type which assurances strut bar. s vertical position and clarifies its advantages and work mechanism. Then it is put forward static theoretical analysis to the structure and compared it with actual measurement. It draws some conclusions such as cable tension and arch spring height is nonlinear variation; after that variation is linear and the slope is equal to theoretical value; at last, spring height increases rapidly and the slope is greater than the theoretic one. Real structure. s stiffness is less than theoretical stiffness. The adjustment of the dog-bone type makes full use of vertical position immobility of strut. Finally the construction procedure of the beam string is described.
It is introduced a new kind of beam string structure with adjustment of the dog-bone type. First it carries on a study on the conjunction methods of strut bar and cable and according to the problem that strut bar. s vertical accuracy can. t be ensured under construction of beam string, it is put forward a settling method that adopted the adjustment of the dog-bone type which assurances strut bar. s vertical position and clarifies its advantages and work mechanism. Then it is put forward static theoretical analysis to the structure and compared it with actual measurement. It draws some conclusions such as cable tension and arch spring height is nonlinear variation; after that variation is linear and the slope is equal to theoretical value; at last, spring height increases rapidly and the slope is greater than the theoretic one. Real structure. s stiffness is less than theoretical stiffness. The adjustment of the dog-bone type makes full use of vertical position immobility of strut. Finally the construction procedure of the beam string is described.
2008, 38(1): 96-99,105.
doi: 10.13204/j.gyjz200801024
Abstract:
The form-finding analysis of the basketball gymnasium combined-roof membrane structure for SIAS International College of Zhengzhou University is conducted by ANSYS. The membrane shape which meets the shape of initial architectural design is determined and the stress in the membrane is evenly distributed. With the form-finding analysis of this close combined-roof membrane structure, the problems in the form-finding processes such as division of element, boundary condition treatments and value adoption of elastic modulus is approached which improves the form-finding efficiency. At last, the coordinated form-finding analysis between cable membrane and steel truss support system is studied, which puts forward the necessity of coordinated form-finding analysis.
The form-finding analysis of the basketball gymnasium combined-roof membrane structure for SIAS International College of Zhengzhou University is conducted by ANSYS. The membrane shape which meets the shape of initial architectural design is determined and the stress in the membrane is evenly distributed. With the form-finding analysis of this close combined-roof membrane structure, the problems in the form-finding processes such as division of element, boundary condition treatments and value adoption of elastic modulus is approached which improves the form-finding efficiency. At last, the coordinated form-finding analysis between cable membrane and steel truss support system is studied, which puts forward the necessity of coordinated form-finding analysis.
2008, 38(1): 100-102.
doi: 10.13204/j.gyjz200801025
Abstract:
When the W/t ratio is large in square concrete filled steel tubes, the part disability of the section due to local buckling of steel plates should be considered. Reinforcing ribs can help to solve this problem. The buckling coefficient k is analyzed by varying diameters of the steel plate with ribs, and the influence of the dimension of the reinforcing ribs is obtained. Two conditions should be satisfied when choosing ribs. The process and checking method of arranging the ribs in large W/t ratio columns are also given.
When the W/t ratio is large in square concrete filled steel tubes, the part disability of the section due to local buckling of steel plates should be considered. Reinforcing ribs can help to solve this problem. The buckling coefficient k is analyzed by varying diameters of the steel plate with ribs, and the influence of the dimension of the reinforcing ribs is obtained. Two conditions should be satisfied when choosing ribs. The process and checking method of arranging the ribs in large W/t ratio columns are also given.
2008, 38(1): 103-105.
doi: 10.13204/j.gyjz200801026
Abstract:
Beam-string structures have been adopted in several large-span structures. However, theoretical analysis of this kind of structures has not been well established. The effects of the imperfections, rise-span ratio, sag-span ratio and prestressing value on the mechanical performance are researched under uniform ful-l span load and hal-f span load. So the optimal rise-span ratio of the arch is obtained. These conclusions provide some useful suggestions for the design of beamstring structures.
Beam-string structures have been adopted in several large-span structures. However, theoretical analysis of this kind of structures has not been well established. The effects of the imperfections, rise-span ratio, sag-span ratio and prestressing value on the mechanical performance are researched under uniform ful-l span load and hal-f span load. So the optimal rise-span ratio of the arch is obtained. These conclusions provide some useful suggestions for the design of beamstring structures.
2008, 38(1): 106-109.
doi: 10.13204/j.gyjz200801027
Abstract:
Depending on the experiment results analysis of the reinforced concrete frame eccentrically braced with steel (EBF structure) and drift limit comparison of performance-based design and three-stage seismic design, the deflection and behavior of EBF structure under seismic motion is discussed. From the point of three-stage principle of seismic design and performance-based design, the story-drift limit of EBF structure should be more strict than the pure frame. Because of the action of steel brace, the shear force of column in EBF structure is reduced and lateral stiffness of EBF structure is increased. The rupture of column and larger lateral deformation are avoided. It is also found that maximum deformation, acceleration, velocity and column shear of the EBF structure are obviously decreased comparing with the pure frame. The K-type brace is advantageous for the earthquake resistance.
Depending on the experiment results analysis of the reinforced concrete frame eccentrically braced with steel (EBF structure) and drift limit comparison of performance-based design and three-stage seismic design, the deflection and behavior of EBF structure under seismic motion is discussed. From the point of three-stage principle of seismic design and performance-based design, the story-drift limit of EBF structure should be more strict than the pure frame. Because of the action of steel brace, the shear force of column in EBF structure is reduced and lateral stiffness of EBF structure is increased. The rupture of column and larger lateral deformation are avoided. It is also found that maximum deformation, acceleration, velocity and column shear of the EBF structure are obviously decreased comparing with the pure frame. The K-type brace is advantageous for the earthquake resistance.
2008, 38(1): 110-113.
doi: 10.13204/j.gyjz200801028
Abstract:
The main characteristics of lamella reticulated shells are introduced in this paper. According to an engineering example of lamella reticulated shells, the principle of strengthening is indicated for reticulated shells. Based on the results of structural calculation, the main problem is gained for the long-span reticulated shells. Carbon fiber sheet strengthening method is a perfect strengthening method for reticulated shells as comparied with other strengthening methods. So the method could offer experience for the similar strengthening projects.
The main characteristics of lamella reticulated shells are introduced in this paper. According to an engineering example of lamella reticulated shells, the principle of strengthening is indicated for reticulated shells. Based on the results of structural calculation, the main problem is gained for the long-span reticulated shells. Carbon fiber sheet strengthening method is a perfect strengthening method for reticulated shells as comparied with other strengthening methods. So the method could offer experience for the similar strengthening projects.
2008, 38(1): 114-116.
doi: 10.13204/j.gyjz200801029
Abstract:
The earthen architecture site is a rare cultural heritage which is destroyed seriously. The protections of the earthen architecture site include two aspects which are chemistry and physics protection at present. Compared with chemical protection, the structure stability is more important. Combined the protected project of Gaochang Soil Ruins in Xinjiang, the new type anchor of geo-filament anchor is used, whose construction technology is introduced; in addition, the numerical comparative tests in typical soil medium were implemented and compared the bearing capacity of anchor from the different affections. According the test results, the surface state affects the anchor force obviously; the length of archor is feasible from 018～115m. Geo-filament archor is proved to be an excellent material which is used in the walls reinforcement of earthen architecture sites, and it has many typical characters which are advanced technology, novel techniques and convenient construction. Because of that, the new research will play an important part in guiding us to protect the earthen architecture sites.
The earthen architecture site is a rare cultural heritage which is destroyed seriously. The protections of the earthen architecture site include two aspects which are chemistry and physics protection at present. Compared with chemical protection, the structure stability is more important. Combined the protected project of Gaochang Soil Ruins in Xinjiang, the new type anchor of geo-filament anchor is used, whose construction technology is introduced; in addition, the numerical comparative tests in typical soil medium were implemented and compared the bearing capacity of anchor from the different affections. According the test results, the surface state affects the anchor force obviously; the length of archor is feasible from 018～115m. Geo-filament archor is proved to be an excellent material which is used in the walls reinforcement of earthen architecture sites, and it has many typical characters which are advanced technology, novel techniques and convenient construction. Because of that, the new research will play an important part in guiding us to protect the earthen architecture sites.
2008, 38(1): 117-119.
doi: 10.13204/j.gyjz200801030
Abstract:
Through an engineering example, the use of lif-t up technology in the incresing beams and removing column method was introduced, which would provide other similar projects with practical experience and theoretical method of analysis.
Through an engineering example, the use of lif-t up technology in the incresing beams and removing column method was introduced, which would provide other similar projects with practical experience and theoretical method of analysis.
