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2013 Vol. 43, No. 12
Display Method:
2013, 43(12): 1-11.
doi: 10.13204/j.gyjz201312001
Abstract:
The sag Rods connected to the webs of puRlins weRe RegaRded as the lateRal elastic suppoRts of the puRlins. The formulas for calculating the Rigidity of the sag Rod weRe established by deRiving the web deformation of the puRlin accoRding to the theoRy of plate and shell，and then the Rigidity of the sag Rod taking account of the web deformation was got，which was modified by FE analysis. It was found that for a Z-section puRlin undeR wind suction，the Reaction within the sag Rod was small. Hence theRe would be a veRy limited effect on the stRess，and also a small distoRtional deformation of the sag Rod section if the sag Rod was simplified as a lateRal Rigid suppoRt oR elastic one. FoR the Z-section the calculated stRess would have excellent accuRacy when the EC3 method，two-way bending method and the method of one-way bending about the paRallel axis weRe used.
The sag Rods connected to the webs of puRlins weRe RegaRded as the lateRal elastic suppoRts of the puRlins. The formulas for calculating the Rigidity of the sag Rod weRe established by deRiving the web deformation of the puRlin accoRding to the theoRy of plate and shell，and then the Rigidity of the sag Rod taking account of the web deformation was got，which was modified by FE analysis. It was found that for a Z-section puRlin undeR wind suction，the Reaction within the sag Rod was small. Hence theRe would be a veRy limited effect on the stRess，and also a small distoRtional deformation of the sag Rod section if the sag Rod was simplified as a lateRal Rigid suppoRt oR elastic one. FoR the Z-section the calculated stRess would have excellent accuRacy when the EC3 method，two-way bending method and the method of one-way bending about the paRallel axis weRe used.
2013, 43(12): 12-20.
doi: 10.13204/j.gyjz201312002
Abstract:
The sag Rods in puRlin systems aRe RegaRded as lateRal elastic suppoRts. C-section puRlins undeR wind suction weRe analyzed using the theoRy of thin-walled membeRs, whose Results weRe compaRed with those of FE analysis using ANSYS plate elements. It was found that for C-section puRlins undeR wind suction acting thRough midpoint of uppeR flange，whose hoRizontal Reaction agReed well with that by ANSYS model，and the Reaction in the sag Rod was also in good agReement with ANSYS analysis, except on and neaR the sag Rod cRoss section; on the cRoss-section of the sag Rod，the stResses of the puRlin weRe affected gReatly by distoRsional deformation caused by sag Rod forces. FoR the contRolling compRessive stRess the EC3 appRoach is on the safe side，but for the contRolling tensile stResses at the tip of the uppeR flang lip，distoRsional stRess should be added to the simple bending stRess to achieve acceptable accuRacy.
The sag Rods in puRlin systems aRe RegaRded as lateRal elastic suppoRts. C-section puRlins undeR wind suction weRe analyzed using the theoRy of thin-walled membeRs, whose Results weRe compaRed with those of FE analysis using ANSYS plate elements. It was found that for C-section puRlins undeR wind suction acting thRough midpoint of uppeR flange，whose hoRizontal Reaction agReed well with that by ANSYS model，and the Reaction in the sag Rod was also in good agReement with ANSYS analysis, except on and neaR the sag Rod cRoss section; on the cRoss-section of the sag Rod，the stResses of the puRlin weRe affected gReatly by distoRsional deformation caused by sag Rod forces. FoR the contRolling compRessive stRess the EC3 appRoach is on the safe side，but for the contRolling tensile stResses at the tip of the uppeR flang lip，distoRsional stRess should be added to the simple bending stRess to achieve acceptable accuRacy.
2013, 43(12): 21-25.
doi: 10.13204/j.gyjz201312003
Abstract:
It was analyzed the stress and deformation of a simple purlin with two sag rods under wind suction，whose roof sheets were connected to the upper flange of the purlin by self-drilled screws; the analytic results were compared with those of FEA. It was found by the analyses that the theory of twisting about upper flange could predict more accurately the lateral deformation of the lower flange，the reaction of the sag rod，and the reaction of the roof sheets close to the non-sag rod zone. There was a maximum compressive stress at the lower flange lip on the section of the sag rod，whose result calculated by EC3 method agreed well with that of ANSYS; there was a maximum tensile stress at the upper flange lip on the section of the sag rod, hence the effect of the distortional deformation must be taken into account. In such case the theory of bending and twisting must be used to calculate the reaction of the sag rod，only then can the positive stress due to the distortional deformation be introduced.
It was analyzed the stress and deformation of a simple purlin with two sag rods under wind suction，whose roof sheets were connected to the upper flange of the purlin by self-drilled screws; the analytic results were compared with those of FEA. It was found by the analyses that the theory of twisting about upper flange could predict more accurately the lateral deformation of the lower flange，the reaction of the sag rod，and the reaction of the roof sheets close to the non-sag rod zone. There was a maximum compressive stress at the lower flange lip on the section of the sag rod，whose result calculated by EC3 method agreed well with that of ANSYS; there was a maximum tensile stress at the upper flange lip on the section of the sag rod, hence the effect of the distortional deformation must be taken into account. In such case the theory of bending and twisting must be used to calculate the reaction of the sag rod，only then can the positive stress due to the distortional deformation be introduced.
2013, 43(12): 26-33.
doi: 10.13204/j.gyjz201312004
Abstract:
Based on the buckling theory of thin-walled members，it was derived the total potentials for instability of cold-formed Z-purlins under wind suction whose lateral displacement of top flange was prohibited. The expressions of the critical moments of the purlins without and with one sag rod were obtained. The results were compared with numerical results using shell elements of ANSYS. It was explored the internal essence of the global stability of the purlin，it was shown by the calculation that the sag rod could be regarded as lateral full support of the purlin.
Based on the buckling theory of thin-walled members，it was derived the total potentials for instability of cold-formed Z-purlins under wind suction whose lateral displacement of top flange was prohibited. The expressions of the critical moments of the purlins without and with one sag rod were obtained. The results were compared with numerical results using shell elements of ANSYS. It was explored the internal essence of the global stability of the purlin，it was shown by the calculation that the sag rod could be regarded as lateral full support of the purlin.
2013, 43(12): 34-37,11.
doi: 10.13204/j.gyjz201312005
Abstract:
Using the theory of thin-walled members，this paper derived the total potential for bending and torsional buckling of C purlins under wind suction，the expression of the critical moments of the purlins was proposed，whose results were compared with those of ANSYS model. The critical moment formula without taking account of deformation effect before buckling was given，and the possible use of the model and the formulas were pointed out by comparing EC3 method with the test results，showing that EC3 method was conservative，yet the proposed formula was simple, whose calculated length coefficient was 10% smaller and bearing capacity was about 20% higher than EC3 method.
Using the theory of thin-walled members，this paper derived the total potential for bending and torsional buckling of C purlins under wind suction，the expression of the critical moments of the purlins was proposed，whose results were compared with those of ANSYS model. The critical moment formula without taking account of deformation effect before buckling was given，and the possible use of the model and the formulas were pointed out by comparing EC3 method with the test results，showing that EC3 method was conservative，yet the proposed formula was simple, whose calculated length coefficient was 10% smaller and bearing capacity was about 20% higher than EC3 method.
2013, 43(12): 38-44.
doi: 10.13204/j.gyjz201312006
Abstract:
It was analyzed the distortional buckling of the flange-lip section in closed form solution. Through modelling the flange-lip section as a parallel system resisting bending loads, it was also proposed formulas to calculate the equivalent bending rigidity of the lip. Using the analytic methods，the bucklings of Z and C sections under axial loading were investigated. The critical stresses of local and distortional bucklings，buckling factors，together with buckling wave-length. Approximate formulas with excellent accuracy were proposed.
It was analyzed the distortional buckling of the flange-lip section in closed form solution. Through modelling the flange-lip section as a parallel system resisting bending loads, it was also proposed formulas to calculate the equivalent bending rigidity of the lip. Using the analytic methods，the bucklings of Z and C sections under axial loading were investigated. The critical stresses of local and distortional bucklings，buckling factors，together with buckling wave-length. Approximate formulas with excellent accuracy were proposed.
2013, 43(12): 45-51,33.
doi: 10.13204/j.gyjz201312007
Abstract:
It was analyzed the distortional buckling of the C and Z sections under bending. In the current Australian and American codes the thin-walled member theory is used to analyze the distortional buckling loads. In this method a reduced restraining rigidity of web to flange is adopted because such a model overestimates the rigidity of flange-lip section. It was derived the formulas to calculate restraining rigidities of web to flange, by using the equivalent bending rigidity of the lip，as well as the theory of plate element，which were used to calculate the local and distortional bucklings of flange-lip sections，whose results were compared with those of FEM，by which the buckling factors had excellent accuracy，and they were on the safe side.
It was analyzed the distortional buckling of the C and Z sections under bending. In the current Australian and American codes the thin-walled member theory is used to analyze the distortional buckling loads. In this method a reduced restraining rigidity of web to flange is adopted because such a model overestimates the rigidity of flange-lip section. It was derived the formulas to calculate restraining rigidities of web to flange, by using the equivalent bending rigidity of the lip，as well as the theory of plate element，which were used to calculate the local and distortional bucklings of flange-lip sections，whose results were compared with those of FEM，by which the buckling factors had excellent accuracy，and they were on the safe side.
2013, 43(12): 52-56,65.
doi: 10.13204/j.gyjz201312008
Abstract:
Taking the bottom flange of purlins as compressed bars and the sag rods as lateral elastic supports along the length of purlins，threshold rigidities of elastic supports which make purlins buckle between adjacent sag rods were found analytically，and the relation of the buckling load and the lateral support rigidity was presented in case the rigidity was less than the threshold values. Calculation was carried out for 24 purlins with thickness of 1. 5 ～ 3 mm and height of 140 ～ 250 mm to check whether sag rods could be regarded as full lateral supports for stability of purlins，and it was found that if the sag rods were close to the centroid of purlins，the purlins were thin，and the distance between sag rods small, then the sag rods could not be regarded as full lateral supports, and measures should be taken in design of purlins.
Taking the bottom flange of purlins as compressed bars and the sag rods as lateral elastic supports along the length of purlins，threshold rigidities of elastic supports which make purlins buckle between adjacent sag rods were found analytically，and the relation of the buckling load and the lateral support rigidity was presented in case the rigidity was less than the threshold values. Calculation was carried out for 24 purlins with thickness of 1. 5 ～ 3 mm and height of 140 ～ 250 mm to check whether sag rods could be regarded as full lateral supports for stability of purlins，and it was found that if the sag rods were close to the centroid of purlins，the purlins were thin，and the distance between sag rods small, then the sag rods could not be regarded as full lateral supports, and measures should be taken in design of purlins.
2013, 43(12): 57-61.
doi: 10.13204/j.gyjz201312009
Abstract:
In Chinese modern times，there were a large number of industrial commercial buildings built in Wuxi City because of the rapid development of industry and commerce in the city. Combined with the construction instance，it was described the industrial and commercial development history of Wuxi in modern times. At the meanwhile，based on the concept of constructing structures and buildings led by commodity economy，it was tried to discuss and analyse the causes and characteristics of the different styles of industrial commercial buildings of Wuxi in morden times from three levels. It was revealed that the vital relations among the construction of buildings，the consciousness of commodity economy and generalization in industrial and commercial development of Wuxi in modern times.
In Chinese modern times，there were a large number of industrial commercial buildings built in Wuxi City because of the rapid development of industry and commerce in the city. Combined with the construction instance，it was described the industrial and commercial development history of Wuxi in modern times. At the meanwhile，based on the concept of constructing structures and buildings led by commodity economy，it was tried to discuss and analyse the causes and characteristics of the different styles of industrial commercial buildings of Wuxi in morden times from three levels. It was revealed that the vital relations among the construction of buildings，the consciousness of commodity economy and generalization in industrial and commercial development of Wuxi in modern times.
2013, 43(12): 62-65.
doi: 10.13204/j.gyjz201312010
Abstract:
From the humanistic perspective，it was probed into three levels needs which people ask for the city, namely，safety needs，belonging emotional needs and fairness justice needs. It was put forward the relationship among the urban safety，urban heritage conservation，urban diversity，social equity，public participation and the humanistic urban planning，and combining with examples it was explored ways of using these five aspects in urban planning. The conclusion could play a guiding role in China's contemporary urban planning.
From the humanistic perspective，it was probed into three levels needs which people ask for the city, namely，safety needs，belonging emotional needs and fairness justice needs. It was put forward the relationship among the urban safety，urban heritage conservation，urban diversity，social equity，public participation and the humanistic urban planning，and combining with examples it was explored ways of using these five aspects in urban planning. The conclusion could play a guiding role in China's contemporary urban planning.
2013, 43(12): 66-70.
doi: 10.13204/j.gyjz201312011
Abstract:
It was presented the conceptual planning of Foshan International Purchase and Ｒegional Logistics Center. The goal of the conceptual planning is to build a logistics center that has a distinctive image，and realize a high efficient transmission of energy，material and information，based on the enlightenment of the cell functional theory, relying on natural conditions，as well as through cultivation an open and sustainable growth ecomatrix system with a scientific，advanced and highly convenient public transportation network.
It was presented the conceptual planning of Foshan International Purchase and Ｒegional Logistics Center. The goal of the conceptual planning is to build a logistics center that has a distinctive image，and realize a high efficient transmission of energy，material and information，based on the enlightenment of the cell functional theory, relying on natural conditions，as well as through cultivation an open and sustainable growth ecomatrix system with a scientific，advanced and highly convenient public transportation network.
2013, 43(12): 71-73.
doi: 10.13204/j.gyjz201312012
Abstract:
Based on the design of reconstructing the old culture square, the spatial layout of Shanghai Culture Plaza is made to be rational and practical. As a result，a delicate，elegant and rich cultural spirit urban oasis that integrates music，art，greenbelt and recreational functions can be created by the concept and starting point of taking the greenness as the predominance，and combining culture with greenness , as well as making full use of embodying the french modern landscape gardening techniques.
Based on the design of reconstructing the old culture square, the spatial layout of Shanghai Culture Plaza is made to be rational and practical. As a result，a delicate，elegant and rich cultural spirit urban oasis that integrates music，art，greenbelt and recreational functions can be created by the concept and starting point of taking the greenness as the predominance，and combining culture with greenness , as well as making full use of embodying the french modern landscape gardening techniques.
2013, 43(12): 74-77,87.
doi: 10.13204/j.gyjz201312013
Abstract:
The tests of nine concrete columns reinforced with fine grain steel bars under eccentric compression were made，the effects of experimental parameters such as eccentricity distance，longitudinal compressive reinforcement ratio，concrete strength and slenderness ratio on their compression performance were studied. Components'failure processes were described; load-strain curves of concrete and steel bars and load-deformation curves were analyzed. Experimental results show that theoretic values of eccentric ＲC column ultimate bearing capacity，average crack spacing and maximal crack width calculated by current code for design of concrete structures are in accordance well with the experimental values. Bearing capacities of eccentric ＲC columns reinforced with HＲBF400 have enough safety factors and tends to conservatively while the yield strength of HＲBF400 was considered as 360 MPa. Under normal service state，maximal crack widths of large compression columns under shot-term load meet the requirement of the current code.
The tests of nine concrete columns reinforced with fine grain steel bars under eccentric compression were made，the effects of experimental parameters such as eccentricity distance，longitudinal compressive reinforcement ratio，concrete strength and slenderness ratio on their compression performance were studied. Components'failure processes were described; load-strain curves of concrete and steel bars and load-deformation curves were analyzed. Experimental results show that theoretic values of eccentric ＲC column ultimate bearing capacity，average crack spacing and maximal crack width calculated by current code for design of concrete structures are in accordance well with the experimental values. Bearing capacities of eccentric ＲC columns reinforced with HＲBF400 have enough safety factors and tends to conservatively while the yield strength of HＲBF400 was considered as 360 MPa. Under normal service state，maximal crack widths of large compression columns under shot-term load meet the requirement of the current code.
2013, 43(12): 78-81,103.
doi: 10.13204/j.gyjz201312014
Abstract:
Deflection tests of seven self-developed new CFRP-PCPs composite reinforced concrete beams were carried out. It was found by comparison that the deflection of CFRP-PCPs composite reinforced concrete beams of all the forced stages was smaller than ordinary prestress CFRP reinforced concrete beams. The deflection of the CFRP-PCPs composite reinforced concrete beams was related to the tension control stress and the cross-sectional area of the composite bar. With the increase of composite prestress and the area，the deflection of the members decreased to some extent. Based on the principle of equivalence of CFRP-PCPs composite reinforcement，the formula of short-term stiffness which suitable for prestressed reinforced concrete beams inCode for Design of Concrete Structures was revised. A suggested formula was put forward which applies to the new type concrete beams of CFRP-PCPs，and the proposed formula was used to compare the five test beams with CFRP-PCPs composite bar. The result shows that the calculated values were accordance well with the experimental values.
Deflection tests of seven self-developed new CFRP-PCPs composite reinforced concrete beams were carried out. It was found by comparison that the deflection of CFRP-PCPs composite reinforced concrete beams of all the forced stages was smaller than ordinary prestress CFRP reinforced concrete beams. The deflection of the CFRP-PCPs composite reinforced concrete beams was related to the tension control stress and the cross-sectional area of the composite bar. With the increase of composite prestress and the area，the deflection of the members decreased to some extent. Based on the principle of equivalence of CFRP-PCPs composite reinforcement，the formula of short-term stiffness which suitable for prestressed reinforced concrete beams inCode for Design of Concrete Structures was revised. A suggested formula was put forward which applies to the new type concrete beams of CFRP-PCPs，and the proposed formula was used to compare the five test beams with CFRP-PCPs composite bar. The result shows that the calculated values were accordance well with the experimental values.
2013, 43(12): 82-87.
doi: 10.13204/j.gyjz201312015
Abstract:
Through bending experiments the paper tested the flexural behaviors of 8 C80 high strength reinforced concrete beams，whose failure modes were studied; and deflections，strains and cracks development were also measured and recorded at 1，3，7，28，90 d. In order to study the influence of the early load (50% of ultimate compressive strength) on the long-term performance of beams，it was also carried out the tests in which beams were loaded to a level about 50% of ultimate compressive strength and then unloaded at the age of 1, 3, 7 d. After that the specimens were cured under natural conditions for 28 d and then were tested again. The two tests'results show that the cracking load，yield load and ultimate load of specimens in the concrete early age(3 d ago) were influenced by ages greatly and were affected little after 3 d，the degree was about 3% after 7 d. The ultimate moment of C80 reinforced concrete beams of 1 d age can reach the 90% of that of 28 d. The cross-section strains at various concrete ages were agreed with those of plane section assumption. The beam carried 50% ultimate load at concrete early age which has smaller influence on deformation capacity and greater one on carrying capacity.
Through bending experiments the paper tested the flexural behaviors of 8 C80 high strength reinforced concrete beams，whose failure modes were studied; and deflections，strains and cracks development were also measured and recorded at 1，3，7，28，90 d. In order to study the influence of the early load (50% of ultimate compressive strength) on the long-term performance of beams，it was also carried out the tests in which beams were loaded to a level about 50% of ultimate compressive strength and then unloaded at the age of 1, 3, 7 d. After that the specimens were cured under natural conditions for 28 d and then were tested again. The two tests'results show that the cracking load，yield load and ultimate load of specimens in the concrete early age(3 d ago) were influenced by ages greatly and were affected little after 3 d，the degree was about 3% after 7 d. The ultimate moment of C80 reinforced concrete beams of 1 d age can reach the 90% of that of 28 d. The cross-section strains at various concrete ages were agreed with those of plane section assumption. The beam carried 50% ultimate load at concrete early age which has smaller influence on deformation capacity and greater one on carrying capacity.
2013, 43(12): 88-92.
doi: 10.13204/j.gyjz201312016
Abstract:
Based on the latest revision of Code for Design of Concrete Structures ( GB500102010 ), transformation formulae for crack width checking is established. Firstly，curves which are related to ratio of reinforcement for longitudinal tensile steel reinforcement，stress in longitudinal steel reinforcement and diameter of steel bar are substituted for curves，which has the function of ratio of steel reinforcement for tensile steel reinforcements calculated according to effective tension sectional area of concrete，stress in longitudinal steel reinforcement and diameter of steel bar. Important messages and tables are also given without checking the crack width of reinforced concrete members. Finally，an accurate simplified expression for the largest diameter of steel bar is proposed. In flexural member's design, there is no need to check crack width but select largest diameter of steel bars according to the specific tables or approximate expression provided in the text，which shall be met the demand of crack width checking automatically.
Based on the latest revision of Code for Design of Concrete Structures ( GB500102010 ), transformation formulae for crack width checking is established. Firstly，curves which are related to ratio of reinforcement for longitudinal tensile steel reinforcement，stress in longitudinal steel reinforcement and diameter of steel bar are substituted for curves，which has the function of ratio of steel reinforcement for tensile steel reinforcements calculated according to effective tension sectional area of concrete，stress in longitudinal steel reinforcement and diameter of steel bar. Important messages and tables are also given without checking the crack width of reinforced concrete members. Finally，an accurate simplified expression for the largest diameter of steel bar is proposed. In flexural member's design, there is no need to check crack width but select largest diameter of steel bars according to the specific tables or approximate expression provided in the text，which shall be met the demand of crack width checking automatically.
2013, 43(12): 93-97.
doi: 10.13204/j.gyjz201312017
Abstract:
Ｒelying on tunnel shield excavation of the Subway Line No. 1 in Wuxi，a series of triaxial tests were performed with different stress path using the undisturbed soil drilled in the construction field in laboratory based on disturbance properties around tunnel. Test results showed that the strength and deformation behavior of soils were highly affected by stress paths. Soil shear strength decreased in turn according to the order of constant stress ratio loading triaxial compression，conventional triaxial compression，axial loading-radial unloading triaxial compression and reduced triaxial compression. The axial strain and soil strength with unloading stress paths were less than those with loading stress paths. In addition，soil shear strength with triaxial compression stress paths was much larger than those obtained through triaxial stretch stress paths.
Ｒelying on tunnel shield excavation of the Subway Line No. 1 in Wuxi，a series of triaxial tests were performed with different stress path using the undisturbed soil drilled in the construction field in laboratory based on disturbance properties around tunnel. Test results showed that the strength and deformation behavior of soils were highly affected by stress paths. Soil shear strength decreased in turn according to the order of constant stress ratio loading triaxial compression，conventional triaxial compression，axial loading-radial unloading triaxial compression and reduced triaxial compression. The axial strain and soil strength with unloading stress paths were less than those with loading stress paths. In addition，soil shear strength with triaxial compression stress paths was much larger than those obtained through triaxial stretch stress paths.
2013, 43(12): 98-103.
doi: 10.13204/j.gyjz201312018
Abstract:
Some kinds of refuse elements were mixed according to classic proportion indoors. Long time landfill test was done with interior settlement apparatus at stated leachating condition. In the course of whole landfill, settlement values were termly measured. On the basis of Gandolla model, considering the speciality of refuse immediate settlement and long term settlement, composite compressibility model considering refuse whole settlement was adopted. According to the measured date of columnar settlement experiment, the calculation parameters of model were back-figured. As a result, based on the composite settlement model, the calculated values and the measured values of landfill test and field test were basically accordant which showed that the analysis of settlement mechanism and the constructed model were reasonable.
Some kinds of refuse elements were mixed according to classic proportion indoors. Long time landfill test was done with interior settlement apparatus at stated leachating condition. In the course of whole landfill, settlement values were termly measured. On the basis of Gandolla model, considering the speciality of refuse immediate settlement and long term settlement, composite compressibility model considering refuse whole settlement was adopted. According to the measured date of columnar settlement experiment, the calculation parameters of model were back-figured. As a result, based on the composite settlement model, the calculated values and the measured values of landfill test and field test were basically accordant which showed that the analysis of settlement mechanism and the constructed model were reasonable.
2013, 43(12): 104-108,161.
doi: 10.13204/j.gyjz201312019
Abstract:
Utilizing CEL (Coupled Eulerian-Lagrangian) finite element method，the penetration process of spudcan foundation was numerically simulated. The penetration mechanism of spudcan foundation into uniform clay，uniform sand and sand overlying clay was respectively explored. Through comparing the finite element predictions with available model centrifuge test results，the rationality of the proposed CEL model was validated，which showed that there existed appreciably large discrepancy in simulating deep penetration using analytical formulations based on bearing capacity theory of circular shallow foundations. The effect on the penetration resistance curve was studied to internal friction angle of upper sand and undrained strength of lower clay. The results could be of reference to design of spudcan foundation in layered soil.
Utilizing CEL (Coupled Eulerian-Lagrangian) finite element method，the penetration process of spudcan foundation was numerically simulated. The penetration mechanism of spudcan foundation into uniform clay，uniform sand and sand overlying clay was respectively explored. Through comparing the finite element predictions with available model centrifuge test results，the rationality of the proposed CEL model was validated，which showed that there existed appreciably large discrepancy in simulating deep penetration using analytical formulations based on bearing capacity theory of circular shallow foundations. The effect on the penetration resistance curve was studied to internal friction angle of upper sand and undrained strength of lower clay. The results could be of reference to design of spudcan foundation in layered soil.
2013, 43(12): 109-112,166.
doi: 10.13204/j.gyjz201312020
Abstract:
Based on the strict Lade-Duncan criterion，to take earth pressure problem as plane strain problem，the formulae of the active and passive earth pressure for clay and non-cohesive soil were derived，which could reflect the action of earth pressure more really，considering the intermediate principal stress. Unlike the past papers，the proposed formulae were derived only from the Lade-Duncan criterion，with no help of the SMP criterion. To verify the feasibility of the proposed formulae，the results determined from the proposed formulae were compared with those obtained from the experiment，also with those obtained from Ｒankine's theory. It was shown that the results determined from the proposed formulae enough safety storage，and were in better agreement with those obtained from the experiment.
Based on the strict Lade-Duncan criterion，to take earth pressure problem as plane strain problem，the formulae of the active and passive earth pressure for clay and non-cohesive soil were derived，which could reflect the action of earth pressure more really，considering the intermediate principal stress. Unlike the past papers，the proposed formulae were derived only from the Lade-Duncan criterion，with no help of the SMP criterion. To verify the feasibility of the proposed formulae，the results determined from the proposed formulae were compared with those obtained from the experiment，also with those obtained from Ｒankine's theory. It was shown that the results determined from the proposed formulae enough safety storage，and were in better agreement with those obtained from the experiment.
2013, 43(12): 113-118.
doi: 10.13204/j.gyjz201312021
Abstract:
It is collectively referred to as reinforcing bar which is able to be in the cooperative work with concrete, and improve the bearing capacity of concrete structure and component. It was obtained the theoretical calculation methods of bond-slip constitutive relation through macro and microscopic analysis of reinforcing bar and concrete，and bond stress distribution and macro bond-slip constitutive relation through theoretical and finite element analysis. Finally，it was contrasted the data of theoretical calculation and experiment，and found that the results of the experiment were consistent well with those of the theoretical analysis.
It is collectively referred to as reinforcing bar which is able to be in the cooperative work with concrete, and improve the bearing capacity of concrete structure and component. It was obtained the theoretical calculation methods of bond-slip constitutive relation through macro and microscopic analysis of reinforcing bar and concrete，and bond stress distribution and macro bond-slip constitutive relation through theoretical and finite element analysis. Finally，it was contrasted the data of theoretical calculation and experiment，and found that the results of the experiment were consistent well with those of the theoretical analysis.
2013, 43(12): 119-123.
doi: 10.13204/j.gyjz201312022
Abstract:
It was found that the strands embedded in duct grout of box grider in the mid-span had corroded when an offshore bridge located in Jiaozhou Bay was demolished. The scanning electron microscope，energy spectrum，X-ray diffraction and Ｒaman spectrum were used to analyze the morphology，element distribution and phases composition of rust samples. The results showed that the steel strand exhibited apparent corrosion pits，and in the rust layer ferrum, oxygen，chlorine，sulfur，calcium, silicon and other elements were found. The corrosion products mainly consisted of goethite，hematite，lepidocrocite，magnetite，calcium carbonate，little ferric sulphate and akageneite. There exist some differences in different locations of the rust layer.
It was found that the strands embedded in duct grout of box grider in the mid-span had corroded when an offshore bridge located in Jiaozhou Bay was demolished. The scanning electron microscope，energy spectrum，X-ray diffraction and Ｒaman spectrum were used to analyze the morphology，element distribution and phases composition of rust samples. The results showed that the steel strand exhibited apparent corrosion pits，and in the rust layer ferrum, oxygen，chlorine，sulfur，calcium, silicon and other elements were found. The corrosion products mainly consisted of goethite，hematite，lepidocrocite，magnetite，calcium carbonate，little ferric sulphate and akageneite. There exist some differences in different locations of the rust layer.
2013, 43(12): 124-128.
doi: 10.13204/j.gyjz201312023
Abstract:
With expanded and vitrified beads insulation mortar and insulation block as the main material, the three-in-one exterior wall thermal insulation system based on integration of insulation mortar interior thermal insulation, insulation block self heat-insulation wall and insulation mortar external thermal insulation was built. At the same time its technical structures，material properties，design points and application scope were analyzed in detail.
With expanded and vitrified beads insulation mortar and insulation block as the main material, the three-in-one exterior wall thermal insulation system based on integration of insulation mortar interior thermal insulation, insulation block self heat-insulation wall and insulation mortar external thermal insulation was built. At the same time its technical structures，material properties，design points and application scope were analyzed in detail.
2013, 43(12): 129-132.
doi: 10.13204/j.gyjz201312024
Abstract:
The technique of structure strengthened with prestressed FＲP sheet is an effective technique with a bright future. Strengthening process and prestress loss are two important problems in this technique. According to the size of small beam，strengthening process is improved by adding a base beam，and then it is analyzed that the production mechanism of this process'prestress loss. The formula of prestress loss can be got through analyzing residual strain. By comparison and analysis，it is found that the values by the formula of prestress loss are basically consistent with measured values. In addition, the rate of presstress loss calculated by the formula and that from the measured data are both 15% ～20%.
The technique of structure strengthened with prestressed FＲP sheet is an effective technique with a bright future. Strengthening process and prestress loss are two important problems in this technique. According to the size of small beam，strengthening process is improved by adding a base beam，and then it is analyzed that the production mechanism of this process'prestress loss. The formula of prestress loss can be got through analyzing residual strain. By comparison and analysis，it is found that the values by the formula of prestress loss are basically consistent with measured values. In addition, the rate of presstress loss calculated by the formula and that from the measured data are both 15% ～20%.
2013, 43(12): 133-137.
doi: 10.13204/j.gyjz201312025
Abstract:
Geometry and stiffness of assembled flexible structure are different because of changes in tensioning process and construction sequence. Seeking rational applying sequence is the key to the construction technology. Using the finite element simulation method，and combining with the Nanjing expo center project it was studied the construction sequence of large-span beam string structures. As example，three typical construction sequences' variation tendency of cable force and displacement was analyzed，and then their curves were given. In the end, according to the structure forming state by different construction sequence，some recommendations for selecting construction method are made.
Geometry and stiffness of assembled flexible structure are different because of changes in tensioning process and construction sequence. Seeking rational applying sequence is the key to the construction technology. Using the finite element simulation method，and combining with the Nanjing expo center project it was studied the construction sequence of large-span beam string structures. As example，three typical construction sequences' variation tendency of cable force and displacement was analyzed，and then their curves were given. In the end, according to the structure forming state by different construction sequence，some recommendations for selecting construction method are made.
2013, 43(12): 138-143.
doi: 10.13204/j.gyjz201312026
Abstract:
Microbial induced carbonate precipitation (MICP)，which use microbial catalyzed hydrolysis of urea and to produce calcium carbonate crystals，is tested to treat the leakage of basement external wall in Jinan. S. pasteurii and reactant are injected into the backfill of the crack wall in the upstream face in-situ. After grouting，the results of permeability field test，ultrasonic measurement，ground penetrating radar detection，concrete coring observation, XＲD analysis and SEM analysis show that a CaCO 3 layer forms in the backstream face of the cracked wall and cover the surface of the crack after four months，there is no water leakage in the basement when subjected to raining; the treated soil becomes denser and more uniform; there is lots of CaCO 3 precipitation in the crack and the filling effect is more obvious in the lower part of the cracked wall. The MICP technology provides a new solution to repair the concrete cracks and control the leakage of underground structures.
Microbial induced carbonate precipitation (MICP)，which use microbial catalyzed hydrolysis of urea and to produce calcium carbonate crystals，is tested to treat the leakage of basement external wall in Jinan. S. pasteurii and reactant are injected into the backfill of the crack wall in the upstream face in-situ. After grouting，the results of permeability field test，ultrasonic measurement，ground penetrating radar detection，concrete coring observation, XＲD analysis and SEM analysis show that a CaCO 3 layer forms in the backstream face of the cracked wall and cover the surface of the crack after four months，there is no water leakage in the basement when subjected to raining; the treated soil becomes denser and more uniform; there is lots of CaCO 3 precipitation in the crack and the filling effect is more obvious in the lower part of the cracked wall. The MICP technology provides a new solution to repair the concrete cracks and control the leakage of underground structures.
2013, 43(12): 144-148.
doi: 10.13204/j.gyjz201312027
Abstract:
The key of super-long concrete frame structure is to control temperature and concrete shrinkage stresses, according to the analysis of PMSAP and ANSYS，their results and variation tendencies are generally consistent. Owing to construction and equipment requirements，the expansion and contraction joints of super-long concrete frame structures can not be installed，then temperature difference between inside and outside and concrete shrinkage should be decreased. Therefore heat insulation layers and flexible joints should be used to reduce influences of temperature stress; applying normal rebar and prestressing reinforcing bar can control crack effectively.
The key of super-long concrete frame structure is to control temperature and concrete shrinkage stresses, according to the analysis of PMSAP and ANSYS，their results and variation tendencies are generally consistent. Owing to construction and equipment requirements，the expansion and contraction joints of super-long concrete frame structures can not be installed，then temperature difference between inside and outside and concrete shrinkage should be decreased. Therefore heat insulation layers and flexible joints should be used to reduce influences of temperature stress; applying normal rebar and prestressing reinforcing bar can control crack effectively.
2013, 43(12): 149-155.
doi: 10.13204/j.gyjz201312028
Abstract:
As a supplement of the traditional concrete wall-steel beam pin joint，combining with some engineering practice，a concrete wall-steel beam T-plate pin joint has been designed to provide more choices for structural engineers. Experimental study on pulling capability of six joints with different key parameters has been conducted. Performance and load-carrying capacity of this type of joint were obtained.
As a supplement of the traditional concrete wall-steel beam pin joint，combining with some engineering practice，a concrete wall-steel beam T-plate pin joint has been designed to provide more choices for structural engineers. Experimental study on pulling capability of six joints with different key parameters has been conducted. Performance and load-carrying capacity of this type of joint were obtained.
2013, 43(12): 156-161.
doi: 10.13204/j.gyjz201312029
Abstract:
An unusual shaped column subjected to axial compression is located inside the casing of a large scale electrostatic precipitator. Because of the peculiarity of section and configuration of the column，its stability design round strong axis can't comply with the current structural specification. In consideration of initial geometrical imperfections and weld residual stresses，the investigation into stability round the strong axis of column by nonlinear finite element method is conducted. The research results indicate that the column doesn't present the flexural buckling round the strong axis，but presents the elasto-plastic flexural-torsional buckling. The stability increases slightly when the connecting channel shaped steel members between two limbs and the stiffeners located on connecting web are strengthened. The stability is weakened significantly when the width-thickness ratio of connecting web increases. When the slenderness of H shaped steel round the strong axis is kept constant and the height-thickness ratio of H shaped steel web increases，the stability increases. Based on a great many computation results，the evaluation recommendation is proposed for the buckling bearing capacity of column under axial compression round strong axis by numerical regression，and the design method of economical width-thickness ratio of connecting web is proposed.
An unusual shaped column subjected to axial compression is located inside the casing of a large scale electrostatic precipitator. Because of the peculiarity of section and configuration of the column，its stability design round strong axis can't comply with the current structural specification. In consideration of initial geometrical imperfections and weld residual stresses，the investigation into stability round the strong axis of column by nonlinear finite element method is conducted. The research results indicate that the column doesn't present the flexural buckling round the strong axis，but presents the elasto-plastic flexural-torsional buckling. The stability increases slightly when the connecting channel shaped steel members between two limbs and the stiffeners located on connecting web are strengthened. The stability is weakened significantly when the width-thickness ratio of connecting web increases. When the slenderness of H shaped steel round the strong axis is kept constant and the height-thickness ratio of H shaped steel web increases，the stability increases. Based on a great many computation results，the evaluation recommendation is proposed for the buckling bearing capacity of column under axial compression round strong axis by numerical regression，and the design method of economical width-thickness ratio of connecting web is proposed.
2013, 43(12): 162-166.
doi: 10.13204/j.gyjz201312030
Abstract:
Based on the ultimate bearing capacity test of transmission tower structure，it was analyzed the Q460 equalley angle of the stress distribution，failure mode and the ultimate bearing capacity of Q460 equal leg angle which had different slenderness ratio and end constraint conditions by finite element software of ANSYS. The research shows that on the failure mode，the finite element analysis of the buckling mode and test phenomenon are basically consistent; on bearing capacity，for the specimens with slenderness ratio of 30 and 45，there is the difference of only 4% between the results of numerical analysis and experimental value. For the specimen of slenderness ratio 60，the difference is 10% and has a good coincidence. The research results provide the reasonable basis for amending the specification and engineering practice of the Q460 high strength angle.
Based on the ultimate bearing capacity test of transmission tower structure，it was analyzed the Q460 equalley angle of the stress distribution，failure mode and the ultimate bearing capacity of Q460 equal leg angle which had different slenderness ratio and end constraint conditions by finite element software of ANSYS. The research shows that on the failure mode，the finite element analysis of the buckling mode and test phenomenon are basically consistent; on bearing capacity，for the specimens with slenderness ratio of 30 and 45，there is the difference of only 4% between the results of numerical analysis and experimental value. For the specimen of slenderness ratio 60，the difference is 10% and has a good coincidence. The research results provide the reasonable basis for amending the specification and engineering practice of the Q460 high strength angle.
2013, 43(12): 167-172.
doi: 10.13204/j.gyjz201312031
Abstract:
It was studied the nondestructive testing methods of rammed-earth material strength of tulou wall. Through the research of working principle of the rebound hammer and rammed-earth material mechanical properties，the area of the rod end of the rebound hammer was enlarged to improve the detection precision. Combined with the compressive strength test of rammed earth cubes，the testing strength curves of rammed-earth material in different chron were set up. And through the field test，it was verified the applicability of the improved rebound hammer, which laid a foundation for field detection of the tulou (earth-building) in service，and contributed to improving protection measures.
It was studied the nondestructive testing methods of rammed-earth material strength of tulou wall. Through the research of working principle of the rebound hammer and rammed-earth material mechanical properties，the area of the rod end of the rebound hammer was enlarged to improve the detection precision. Combined with the compressive strength test of rammed earth cubes，the testing strength curves of rammed-earth material in different chron were set up. And through the field test，it was verified the applicability of the improved rebound hammer, which laid a foundation for field detection of the tulou (earth-building) in service，and contributed to improving protection measures.
2013, 43(12): 173-174,148.
doi: 10.13204/j.gyjz201312032
Abstract:
Combined with color design of the main mill building of Suizhong Power Plant，based on visual integrity, this paper discusses the color design of main workshop of power plants and gives the principle proposal: on the one hand, contrast unified method can be used to perform modern industrial features with bold and lively color supplement，on the other hand coordinated treatment approach can be used to highlight the design principles of local conditions with suitable geographical environment color.
Combined with color design of the main mill building of Suizhong Power Plant，based on visual integrity, this paper discusses the color design of main workshop of power plants and gives the principle proposal: on the one hand, contrast unified method can be used to perform modern industrial features with bold and lively color supplement，on the other hand coordinated treatment approach can be used to highlight the design principles of local conditions with suitable geographical environment color.
2013, 43(12): 175-179,137.
doi: 10.13204/j.gyjz201312033
Abstract:
The stress mechanism of multi ribbed floor slab under vertical load is analyzed. Analysis shows that the results are a bit different among of different software because of different calculation principle. So the stiffness of column cap needs to be calculated. And the main beams and the moment of the first beams connected with the column caps are affected greatly by the column caps; but the other beams are less affected. Because the column caps are equivalent to a rigid component，which can effectively decrease the calculation length of the beams. So the column caps design needs to be well done in multi ribbed floor slab design. The diagram of the bar of column cap is shown. And the bars of main beams need to be adjusted according to the column caps influence. And the results also show that the stiffness of beam is increased because the slab acts as a flange. So the effect of strong column and weak beam can not be easily achieved.
The stress mechanism of multi ribbed floor slab under vertical load is analyzed. Analysis shows that the results are a bit different among of different software because of different calculation principle. So the stiffness of column cap needs to be calculated. And the main beams and the moment of the first beams connected with the column caps are affected greatly by the column caps; but the other beams are less affected. Because the column caps are equivalent to a rigid component，which can effectively decrease the calculation length of the beams. So the column caps design needs to be well done in multi ribbed floor slab design. The diagram of the bar of column cap is shown. And the bars of main beams need to be adjusted according to the column caps influence. And the results also show that the stiffness of beam is increased because the slab acts as a flange. So the effect of strong column and weak beam can not be easily achieved.
2013, 43(12): 180-182.
doi: 10.13204/j.gyjz201312034
Abstract:
The protection and use of the industrial heritages play an important role in the urban construction and the development. It was analyzed comprehensively the research on industrial heritages and the status of their use in China. Based on which，linked with Shanghai's reality，it also was discussed the domestic first glass museum construction course. It was summarized the excellent case of reforming successfully Shanghai Glass Factory, as well as its protection an use; it was pointed out that the reasonable localization，the accurate decision-making，the rigorous design plan as well as the nimble and efficient later period operation were the basic guarantees of the project success.
The protection and use of the industrial heritages play an important role in the urban construction and the development. It was analyzed comprehensively the research on industrial heritages and the status of their use in China. Based on which，linked with Shanghai's reality，it also was discussed the domestic first glass museum construction course. It was summarized the excellent case of reforming successfully Shanghai Glass Factory, as well as its protection an use; it was pointed out that the reasonable localization，the accurate decision-making，the rigorous design plan as well as the nimble and efficient later period operation were the basic guarantees of the project success.
