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2010 Vol. 40, No. 6
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2010, 40(6): 1-4.
doi: 10.13204/j.gyjz201006001
Abstract:
Erosion-resisting characteristics of C25,C35 and C50 concretes were tested in an environment of freezing and thawing cycle. The result showed that the corrosion became more and more serious successively under clear water,the solution of sodium sulfate,and the solution of sodium sulfate with sodium chloride after 300 times of freezing-thawing actions. The damage to a concrete specimen was gradually serious with a decrease in concrete strength and a gradual increase in water cement ratio. The concrete samples protected by SPUA were in good condition. The main problem was spalling from surface to interior which appeared different tendency with different salt solution.
Erosion-resisting characteristics of C25,C35 and C50 concretes were tested in an environment of freezing and thawing cycle. The result showed that the corrosion became more and more serious successively under clear water,the solution of sodium sulfate,and the solution of sodium sulfate with sodium chloride after 300 times of freezing-thawing actions. The damage to a concrete specimen was gradually serious with a decrease in concrete strength and a gradual increase in water cement ratio. The concrete samples protected by SPUA were in good condition. The main problem was spalling from surface to interior which appeared different tendency with different salt solution.
2010, 40(6): 5-8,20.
doi: 10.13204/j.gyjz201006002
Abstract:
To explore working mechanism and life of prestressed structure under pre-freeze-thawing environment which includes freeze-thaw and dynamic fatigue，this paper searched the main factors of fatigue life and the relative relations. On the basis of test and statistical theory，this paper deduced multivariate curve relation，with effective variables. A model about pre-freeze-thawing coefficient C was built using many test data of members that had undergone different freeze-thaw times T and had different pre-stressed grade S，whose fatigue lives were measured and analyzed. The results show that with the increase of freeze-thawing times T，the fatigue life influence coefficient C decreases，but when the times T reach a certain value，the coefficient C has a complicated relation with pre-stressed grade S. More freeze-thaw times has more influence on higher grade pre-stressed members than the lower ones. This papers model can get the influence coefficient and fatigue lifes predicted value when the survival probability is given.
To explore working mechanism and life of prestressed structure under pre-freeze-thawing environment which includes freeze-thaw and dynamic fatigue，this paper searched the main factors of fatigue life and the relative relations. On the basis of test and statistical theory，this paper deduced multivariate curve relation，with effective variables. A model about pre-freeze-thawing coefficient C was built using many test data of members that had undergone different freeze-thaw times T and had different pre-stressed grade S，whose fatigue lives were measured and analyzed. The results show that with the increase of freeze-thawing times T，the fatigue life influence coefficient C decreases，but when the times T reach a certain value，the coefficient C has a complicated relation with pre-stressed grade S. More freeze-thaw times has more influence on higher grade pre-stressed members than the lower ones. This papers model can get the influence coefficient and fatigue lifes predicted value when the survival probability is given.
2010, 40(6): 9-11,26.
doi: 10.13204/j.gyjz201006003
Abstract:
Inner shear test method was used to study CFRP-concrete bond behavior under freeze-thaw cycles.Through this test，the influence of freeze thaw cycle to interface durabilities was revealed，and scientific basis for structural reinforcement of cold regions was provided. The tests results indicate that freeze-thaw cycles has significant effects on the failure modes of interface between CFRP and concrete. The bond strength and crack initial load of CFRP-concrete exhibit decreasing trends with an increase in number of freeze-thaw cycles.
Inner shear test method was used to study CFRP-concrete bond behavior under freeze-thaw cycles.Through this test，the influence of freeze thaw cycle to interface durabilities was revealed，and scientific basis for structural reinforcement of cold regions was provided. The tests results indicate that freeze-thaw cycles has significant effects on the failure modes of interface between CFRP and concrete. The bond strength and crack initial load of CFRP-concrete exhibit decreasing trends with an increase in number of freeze-thaw cycles.
2010, 40(6): 12-15.
doi: 10.13204/j.gyjz201006004
Abstract:
Depending on the environment coupling of salts and freeze-thaw cycles，the test method of single-side saltfrost was selected and improvement of mineral admixture and air-entraining agent on salt-frost scaling resistance of concrete was researched. The results show that the scaled mass and the dynamic modulus of elasticity loss rate of the concret are reduced as compared with control concrete by adding mineral admixture and air entraining agent into concrete. The salt-frost scaling resistance of concrete is improved. The salt-frost scaling resistance of concrete mixed with ground slag is better than flyash concrete. Compared with the concrete of other proportion the salt-frost resistance of concrete with fly ash，silica fume and air-entraining agent is better. So the mineral admixture coupled technology is promoted in this more complex situation of salt and freeze-thaw cycles. After single-side salt-frost the scaled mass of the concret is more but the dynamic modulus of elasticity loss rate is less，so the damage of concrete mainly depends on the surface scaling.
Depending on the environment coupling of salts and freeze-thaw cycles，the test method of single-side saltfrost was selected and improvement of mineral admixture and air-entraining agent on salt-frost scaling resistance of concrete was researched. The results show that the scaled mass and the dynamic modulus of elasticity loss rate of the concret are reduced as compared with control concrete by adding mineral admixture and air entraining agent into concrete. The salt-frost scaling resistance of concrete is improved. The salt-frost scaling resistance of concrete mixed with ground slag is better than flyash concrete. Compared with the concrete of other proportion the salt-frost resistance of concrete with fly ash，silica fume and air-entraining agent is better. So the mineral admixture coupled technology is promoted in this more complex situation of salt and freeze-thaw cycles. After single-side salt-frost the scaled mass of the concret is more but the dynamic modulus of elasticity loss rate is less，so the damage of concrete mainly depends on the surface scaling.
2010, 40(6): 16-20.
doi: 10.13204/j.gyjz201006005
Abstract:
The simulative experiment was carried out for researching the degradation rule of shear strength,deformation,stiffness and failure mechanism of the reinforced concrete beams under the action of different persistent loading and freeze-thaw cycles and mixed aggressive solution. The conclusion indicate that persistent loading influence the shear capacity of RC beams observably,and the degradation of stiffness and ductility of RC beams arise in part from stirrup corrosion and concrete deterioration in shear-compression zone. Calculation mehtod of shear strength of RC beam under the alternative action of freeze-the cycles and mixed aggressive solution based on the experiment data was also proposed.
The simulative experiment was carried out for researching the degradation rule of shear strength,deformation,stiffness and failure mechanism of the reinforced concrete beams under the action of different persistent loading and freeze-thaw cycles and mixed aggressive solution. The conclusion indicate that persistent loading influence the shear capacity of RC beams observably,and the degradation of stiffness and ductility of RC beams arise in part from stirrup corrosion and concrete deterioration in shear-compression zone. Calculation mehtod of shear strength of RC beam under the alternative action of freeze-the cycles and mixed aggressive solution based on the experiment data was also proposed.
2010, 40(6): 21-26.
doi: 10.13204/j.gyjz201006006
Abstract:
The ductility of a corroded reinforced concrete (RC) beam was investigated. On the condition that the plane cross-section assumption is no longer tenable,the relation between the strain of reinforcement and concrete of beams with different corroded levels in yield state and ultimate state was conjectured based on the regression analysis of the experimental data of 48 beams (32 corroded beams and 12 contrasted beams). Through the strain relation,the computation expression of the compressive height of corroded beam in both yield and ultimate state and the computation model of the curvature ductility factor of corroded beam was deduced. And then based on this computation model,the M- curve of beams with different corroded levels was drawn and the characteristic and reason of the change in ductility was discussed.
The ductility of a corroded reinforced concrete (RC) beam was investigated. On the condition that the plane cross-section assumption is no longer tenable,the relation between the strain of reinforcement and concrete of beams with different corroded levels in yield state and ultimate state was conjectured based on the regression analysis of the experimental data of 48 beams (32 corroded beams and 12 contrasted beams). Through the strain relation,the computation expression of the compressive height of corroded beam in both yield and ultimate state and the computation model of the curvature ductility factor of corroded beam was deduced. And then based on this computation model,the M- curve of beams with different corroded levels was drawn and the characteristic and reason of the change in ductility was discussed.
2010, 40(6): 27-30,78.
doi: 10.13204/j.gyjz201006007
Abstract:
After designing rationally the assessment targets on concrete durability，the assessment parameters are used to show the durability deterioration course of concrete in sulfate environment. The results show that every performance deterioration degree of concrete can be compared on the same coordination axis by assessment parameters. The assessment parameters are applicable to the same determination criterion，and the determination principle is simple and convenient. The comparing of the deterioration course and sensitivity degree of concrete performance is much easy. If concrete performance of anti-sulfate erosion is tested at laboratory，the result assessment ought to be done by the two non-destructive test assessment parameters.
After designing rationally the assessment targets on concrete durability，the assessment parameters are used to show the durability deterioration course of concrete in sulfate environment. The results show that every performance deterioration degree of concrete can be compared on the same coordination axis by assessment parameters. The assessment parameters are applicable to the same determination criterion，and the determination principle is simple and convenient. The comparing of the deterioration course and sensitivity degree of concrete performance is much easy. If concrete performance of anti-sulfate erosion is tested at laboratory，the result assessment ought to be done by the two non-destructive test assessment parameters.
2010, 40(6): 31-35.
doi: 10.13204/j.gyjz201006008
Abstract:
Deformation，cracking，bearing capacity and the failure mechanism of beams with corroded reinforcement under repeated loading were investigated. Twenty sample beams，including 4 uncorroded and 16 corroded reinforced concrete beams were tested under repeated loading. The effect of corrosion rate on the bearing capacity and flexural cracking was presented. Formulas for the bearing capacity and cracking load of corroded beams under repeated load were suggested.
Deformation，cracking，bearing capacity and the failure mechanism of beams with corroded reinforcement under repeated loading were investigated. Twenty sample beams，including 4 uncorroded and 16 corroded reinforced concrete beams were tested under repeated loading. The effect of corrosion rate on the bearing capacity and flexural cracking was presented. Formulas for the bearing capacity and cracking load of corroded beams under repeated load were suggested.
2010, 40(6): 36-39,59.
doi: 10.13204/j.gyjz201006009
Abstract:
Industrial buildings are often exposed to some kinds of industrial media，causing problems of durability and long-term safety in reinforced concrete structures，which threats the directly safety in production. In this paper，three cases of concrete structure deterioration due to different corrosion media，including acid，alkali，industrial chlorides and dry-wet cycle，were investigated. Finally，the items needing attention during design of new industrial mill building and maintenance of old industrial buildings were offered.
Industrial buildings are often exposed to some kinds of industrial media，causing problems of durability and long-term safety in reinforced concrete structures，which threats the directly safety in production. In this paper，three cases of concrete structure deterioration due to different corrosion media，including acid，alkali，industrial chlorides and dry-wet cycle，were investigated. Finally，the items needing attention during design of new industrial mill building and maintenance of old industrial buildings were offered.
2010, 40(6): 40-44.
doi: 10.13204/j.gyjz201006010
Abstract:
The local environment within industrial buildings is greatly various because of its production process，so the durability performance and degradation rate of concrete structures under the environmental effect are different.This article adopts fuzzy mathematics method to confirm the local environmental factors in different environments，which quantifies the relationship between environmental effect and durability damage. Taking the bent columns in different local environment of one foundry workshop as the object and based on the durability data on the workshop，the residual life of the mill building was predicted，whose result was contrasted with actual situation of the mill building.
The local environment within industrial buildings is greatly various because of its production process，so the durability performance and degradation rate of concrete structures under the environmental effect are different.This article adopts fuzzy mathematics method to confirm the local environmental factors in different environments，which quantifies the relationship between environmental effect and durability damage. Taking the bent columns in different local environment of one foundry workshop as the object and based on the durability data on the workshop，the residual life of the mill building was predicted，whose result was contrasted with actual situation of the mill building.
2010, 40(6): 45-47,51.
doi: 10.13204/j.gyjz201006011
Abstract:
The existing industrial buildings had the opportunity to regenerating in the history of urban development since the lapse of their glorious age. In this course of reusing and sustainable development of the existing industrial buildings，environmental control acted as the important backstop technology. In general，the key points of relevant technologies were analyzed and expounded and the technical measures for the existing industrial buildings regeneration and redevelopment were also proposed.
The existing industrial buildings had the opportunity to regenerating in the history of urban development since the lapse of their glorious age. In this course of reusing and sustainable development of the existing industrial buildings，environmental control acted as the important backstop technology. In general，the key points of relevant technologies were analyzed and expounded and the technical measures for the existing industrial buildings regeneration and redevelopment were also proposed.
2010, 40(6): 48-51.
doi: 10.13204/j.gyjz201006012
Abstract:
The state-of-the-art of the conservative and adaptive reuse of old industrial buildings both at home and aboard was summarised. The appropriate ways for the conservative and adaptive reuse of old industrial buildings in Shenyang Tiexi Industrial Zone were proposed. By the design of the conservative and adaptive reuse of old industrial buildings of the mining equipment of Shenyang Heavy Industries Group，old industrial buildings was presented the investigation how to better protect and adaptability reuse. Also a feasible development model for the regeneration of old industrial buildings was found.
The state-of-the-art of the conservative and adaptive reuse of old industrial buildings both at home and aboard was summarised. The appropriate ways for the conservative and adaptive reuse of old industrial buildings in Shenyang Tiexi Industrial Zone were proposed. By the design of the conservative and adaptive reuse of old industrial buildings of the mining equipment of Shenyang Heavy Industries Group，old industrial buildings was presented the investigation how to better protect and adaptability reuse. Also a feasible development model for the regeneration of old industrial buildings was found.
2010, 40(6): 52-55.
doi: 10.13204/j.gyjz201006013
Abstract:
Taking the land for old industrial heritages and the renovation of mill buildings in area of Shanghai World Expo and those of Shougang Group and Coking Plant of Beijing for example，it is explored that the attitude and designing conception that should be used in confronting the theses of industrial heritage protection and development:i. e. the conception of casting aside simple copy and returning to reason and science，as well as faith and invention，which is the core spirit displayed to the public by urban industrial heritages.
Taking the land for old industrial heritages and the renovation of mill buildings in area of Shanghai World Expo and those of Shougang Group and Coking Plant of Beijing for example，it is explored that the attitude and designing conception that should be used in confronting the theses of industrial heritage protection and development:i. e. the conception of casting aside simple copy and returning to reason and science，as well as faith and invention，which is the core spirit displayed to the public by urban industrial heritages.
2010, 40(6): 56-59.
doi: 10.13204/j.gyjz201006014
Abstract:
The traces of urban development can often be obtained from the industrial buildings. As a material carrier of industrial civilization，the reuse of industrial buildings became a hot reasearch subject. Through the analysis of transformation design of Maoxin Flour Mill in Wuxi，the reuse of space and site probed into，the excavation of historical information in the process of reforming industrial buildings were probed into， and the significane of industrial heritage reuse to the urban cultural renaissance was explored.
The traces of urban development can often be obtained from the industrial buildings. As a material carrier of industrial civilization，the reuse of industrial buildings became a hot reasearch subject. Through the analysis of transformation design of Maoxin Flour Mill in Wuxi，the reuse of space and site probed into，the excavation of historical information in the process of reforming industrial buildings were probed into， and the significane of industrial heritage reuse to the urban cultural renaissance was explored.
2010, 40(6): 60-67,73.
doi: 10.13204/j.gyjz201006015
Abstract:
Two thermal behavior experiments of light gauge steel-framed composite walls with slotted studs and withexternal thermal insulation layers were carried in the lab of combined energy consumption test board for components of building envelope in school of municipal and environmental engineering at HIT. The method of thermocouple temperature measurement was used. The heat transfer coefficients and temperature of the measure points of composite wall were deeply investigated. Two conclusions were drawn from the test. According the test，the web slotted studs can reduce heat loss of the light gauge steel-framed composite walls，thus weakening the thermal bridge effect of the location in stud part，then significantly improve the thermal insulation properties of the composite walls; the composite wall heat transfer coefficients of the two test schemes are 0.315 W/ (m2K) and 0.250 W/ (m2K)，which can meet the residential building envelope heat transfer coefficient limit value of cold areas well. Using the standard studs which recommended by Light Gauge Steel Framing Assembly Housing Specification(JG /T 1822005)，standard steel-framed walls were made up and selected as the research object. ANSYS finite element model is used to analyse the wall heat transfer properties. To obtain the goal as the light gauge steel-framed composite wall to meet the Harbin area construction outer wall energy conservation standard，the comprehensive inspection and contrast were analyzed of mean heat conductivity of four kinds of walls，the walls economic comparison was carried on，too. The design scheme of the light gauge steel-framed composite walls was proposed to meet the construction energy conservation standard in cold areas in China.
Two thermal behavior experiments of light gauge steel-framed composite walls with slotted studs and withexternal thermal insulation layers were carried in the lab of combined energy consumption test board for components of building envelope in school of municipal and environmental engineering at HIT. The method of thermocouple temperature measurement was used. The heat transfer coefficients and temperature of the measure points of composite wall were deeply investigated. Two conclusions were drawn from the test. According the test，the web slotted studs can reduce heat loss of the light gauge steel-framed composite walls，thus weakening the thermal bridge effect of the location in stud part，then significantly improve the thermal insulation properties of the composite walls; the composite wall heat transfer coefficients of the two test schemes are 0.315 W/ (m2K) and 0.250 W/ (m2K)，which can meet the residential building envelope heat transfer coefficient limit value of cold areas well. Using the standard studs which recommended by Light Gauge Steel Framing Assembly Housing Specification(JG /T 1822005)，standard steel-framed walls were made up and selected as the research object. ANSYS finite element model is used to analyse the wall heat transfer properties. To obtain the goal as the light gauge steel-framed composite wall to meet the Harbin area construction outer wall energy conservation standard，the comprehensive inspection and contrast were analyzed of mean heat conductivity of four kinds of walls，the walls economic comparison was carried on，too. The design scheme of the light gauge steel-framed composite walls was proposed to meet the construction energy conservation standard in cold areas in China.
2010, 40(6): 68-73.
doi: 10.13204/j.gyjz201006016
Abstract:
Based on the test of 22 bond-slip specimens under the monotonous and repeated dynamical loads，the main factors affecting the bond-anchorage properties，the bond-anchorage mechanism，the bond stress-slip curves and the bond stress-position curves，were also given. According to the comparative tests under the monotonous and repeated dynamical loads，the degeneration performances of bond-anchorage for the specimens with chemical adhesive anchorage bars were investigated.
Based on the test of 22 bond-slip specimens under the monotonous and repeated dynamical loads，the main factors affecting the bond-anchorage properties，the bond-anchorage mechanism，the bond stress-slip curves and the bond stress-position curves，were also given. According to the comparative tests under the monotonous and repeated dynamical loads，the degeneration performances of bond-anchorage for the specimens with chemical adhesive anchorage bars were investigated.
2010, 40(6): 74-78.
doi: 10.13204/j.gyjz201006017
Abstract:
It has theoretical and practical value to carry out the experimental research of simply-supported T-type beam reinforced by externally tendons，whose mechanism can be deeply recognized. By means of the experiment，the service performances of simply-supported beam before and after strengthened by externally tendons were investigated，such as the distribution and development of crack，deflection of mid-span，deformation of whole beam under different loading cases. It can be inferred that the bearing capacity of beam can be improved sharply after strengthening，the development of cracks can be suppressed and the deformation capacity can be improved.
It has theoretical and practical value to carry out the experimental research of simply-supported T-type beam reinforced by externally tendons，whose mechanism can be deeply recognized. By means of the experiment，the service performances of simply-supported beam before and after strengthened by externally tendons were investigated，such as the distribution and development of crack，deflection of mid-span，deformation of whole beam under different loading cases. It can be inferred that the bearing capacity of beam can be improved sharply after strengthening，the development of cracks can be suppressed and the deformation capacity can be improved.
2010, 40(6): 79-84,92.
doi: 10.13204/j.gyjz201006018
Abstract:
The superimposed slab shear wall system，as a new lateral force resisting system，was introduced. This structural system possesses several advantages compared to normal shear wall system，such as good quality control，speedy construction，the low-cost of constructions and the high level industrialization of production. The superimposed slab shear walls system is a new green structure system with good market future. A systematically analytical study on the superimposed slab shear walls was carried out，which provided the reliable scientific basis for compiling the trade standardsTechnical Specification for Superimposed Slab Concrete Shear Wall Structure，Comparative experimental studies on superimposed slab shear walls and general shear walls are carried out. The experimental results show the seismic behaviors of the superimposed slab shear walls are general shear walls are not obviously different.
The superimposed slab shear wall system，as a new lateral force resisting system，was introduced. This structural system possesses several advantages compared to normal shear wall system，such as good quality control，speedy construction，the low-cost of constructions and the high level industrialization of production. The superimposed slab shear walls system is a new green structure system with good market future. A systematically analytical study on the superimposed slab shear walls was carried out，which provided the reliable scientific basis for compiling the trade standardsTechnical Specification for Superimposed Slab Concrete Shear Wall Structure，Comparative experimental studies on superimposed slab shear walls and general shear walls are carried out. The experimental results show the seismic behaviors of the superimposed slab shear walls are general shear walls are not obviously different.
2010, 40(6): 85-88.
doi: 10.13204/j.gyjz201006019
Abstract:
In view of the random and fuzzy characteristics of excavation soil stability，the fuzzy probability of the bottom of the excavation against heave failure was studied. The example's results indicate that the fuzzy probability will increase along with the increasing of the fuzzy transition area. The fuzzy-random analysis method can provide a theoretic basis for determining the safety factor with traditional empiric safety factor method of excavation projects.
In view of the random and fuzzy characteristics of excavation soil stability，the fuzzy probability of the bottom of the excavation against heave failure was studied. The example's results indicate that the fuzzy probability will increase along with the increasing of the fuzzy transition area. The fuzzy-random analysis method can provide a theoretic basis for determining the safety factor with traditional empiric safety factor method of excavation projects.
2010, 40(6): 89-92.
doi: 10.13204/j.gyjz201006020
Abstract:
Based on the theory of soil plasticity，a model of the passive earth pressure from trapezoodal-cross-section finite soil body was built. The proportional relation and the effect of the model parameter on relationship between the passive earth pressure from trapezoodal-cross-section finite soil body and half-space passive earth pressure were researched. A reinforcing deep excavation was designed in Rankine theory and the model introduced in the paper.The effect of the passive earth pressure from trapezoodal-cross-section finite soil body on the stability of deep excavation and municipal slop was revealed，which verified the calculation results by the model.
Based on the theory of soil plasticity，a model of the passive earth pressure from trapezoodal-cross-section finite soil body was built. The proportional relation and the effect of the model parameter on relationship between the passive earth pressure from trapezoodal-cross-section finite soil body and half-space passive earth pressure were researched. A reinforcing deep excavation was designed in Rankine theory and the model introduced in the paper.The effect of the passive earth pressure from trapezoodal-cross-section finite soil body on the stability of deep excavation and municipal slop was revealed，which verified the calculation results by the model.
2010, 40(6): 93-96.
doi: 10.13204/j.gyjz201006021
Abstract:
A experiment of 12 000 kNm energy dynamic compaction for collapsible loess was carried out. Through comprehensive analyzing the data of standard penetration test，soil mechanics experiment，cone penetration test，Rayleigh test，static test，and compare with other energy dynamic compaction results of collapsible loess，some results of effective reinforced depth and coefficient of collapsibility were obtained. References for design，construction，and detection of collapsible loess were provided.
A experiment of 12 000 kNm energy dynamic compaction for collapsible loess was carried out. Through comprehensive analyzing the data of standard penetration test，soil mechanics experiment，cone penetration test，Rayleigh test，static test，and compare with other energy dynamic compaction results of collapsible loess，some results of effective reinforced depth and coefficient of collapsibility were obtained. References for design，construction，and detection of collapsible loess were provided.
2010, 40(6): 97-101.
doi: 10.13204/j.gyjz201006022
Abstract:
In order to study the deformation capacity of steel reinforced concrete (SRC) shear walls，the relationship between drift ratio and cross sections curvature，edge strain，transverse reinforcement characteristic value are theoretically deduced according to SRC shear walls test with low-cycle reversed loading. A drift-based deformation capacity design method was proposed for SRC shear walls. The reliability of the method was verified through test results. It was obtained that the relationships about the drift ratio，the axial compression ratio，the transverse reinforcement characteristic value and shear span ratio. The allowable axial load ratios of SRC shear wall in different seismic grades and transverse reinforcement characteristic value were proposed.
In order to study the deformation capacity of steel reinforced concrete (SRC) shear walls，the relationship between drift ratio and cross sections curvature，edge strain，transverse reinforcement characteristic value are theoretically deduced according to SRC shear walls test with low-cycle reversed loading. A drift-based deformation capacity design method was proposed for SRC shear walls. The reliability of the method was verified through test results. It was obtained that the relationships about the drift ratio，the axial compression ratio，the transverse reinforcement characteristic value and shear span ratio. The allowable axial load ratios of SRC shear wall in different seismic grades and transverse reinforcement characteristic value were proposed.
2010, 40(6): 102-106.
doi: 10.13204/j.gyjz201006023
Abstract:
Through an experimental research on static load-carrying properties of 2 groups of multi-planar complex tubular joints (4 joints) ，the effects of different structural type of the joints on both flow of stresses and damage modes were discussed. A special self-equilibrium spatial loading installation was designed for all tests of the scaled specimens，and the limit states of bearing capacity of the two groups of joints with different ways of being internally stiffened. Reasonable suggestions on design were proposed according to damage modes of the joints obtained by the tests: sufficient bearing capacity of 67FB joint was guaranteed with the two kinds of internally stiffened configuration;cross stiffeners had to be placed in base tube and are reliably welded with the chord member in order to acquire sufficient bearing capacity of 67EB joint.
Through an experimental research on static load-carrying properties of 2 groups of multi-planar complex tubular joints (4 joints) ，the effects of different structural type of the joints on both flow of stresses and damage modes were discussed. A special self-equilibrium spatial loading installation was designed for all tests of the scaled specimens，and the limit states of bearing capacity of the two groups of joints with different ways of being internally stiffened. Reasonable suggestions on design were proposed according to damage modes of the joints obtained by the tests: sufficient bearing capacity of 67FB joint was guaranteed with the two kinds of internally stiffened configuration;cross stiffeners had to be placed in base tube and are reliably welded with the chord member in order to acquire sufficient bearing capacity of 67EB joint.
2010, 40(6): 107-110.
doi: 10.13204/j.gyjz201006024
Abstract:
The semi-rigid steel frame-reinforced concrete infill wall structure (SRCW) ，which combines advantages of a steel frame and a shear wall，is considered as a new type of aseismatic structure with a brilliant future. The FEM study on SRCW structure was localized on the linear elastic stage so far. In order to study seismic behavior and force distribution in the structural system of the SRCW，the basic process for non-linear FEM simulation was expatiated using the software ANSYS，and then the FEM model was validated by experimental data. Based on which the structural behavior was evaluated from four aspects: strength， stiffness， load distribution， ductility and energy dissipation. The analytical results indicate that the structure has ample lateral bearing capacity and high safety factor.The structure has good performances on ductility and energy dissipation. The steel framework undertakes 80%～100% of the whole overturning moment and the infill wall takes 80%～90% of overall lateral load. Finally，suggestions on aseismic design were presented.
The semi-rigid steel frame-reinforced concrete infill wall structure (SRCW) ，which combines advantages of a steel frame and a shear wall，is considered as a new type of aseismatic structure with a brilliant future. The FEM study on SRCW structure was localized on the linear elastic stage so far. In order to study seismic behavior and force distribution in the structural system of the SRCW，the basic process for non-linear FEM simulation was expatiated using the software ANSYS，and then the FEM model was validated by experimental data. Based on which the structural behavior was evaluated from four aspects: strength， stiffness， load distribution， ductility and energy dissipation. The analytical results indicate that the structure has ample lateral bearing capacity and high safety factor.The structure has good performances on ductility and energy dissipation. The steel framework undertakes 80%～100% of the whole overturning moment and the infill wall takes 80%～90% of overall lateral load. Finally，suggestions on aseismic design were presented.
2010, 40(6): 111-112,88.
doi: 10.13204/j.gyjz201006025
Abstract:
It was described that the problems needing attention during the design and construction of the rectangular concrete-filled steel tube double-limb columns.
It was described that the problems needing attention during the design and construction of the rectangular concrete-filled steel tube double-limb columns.
2010, 40(6): 113-117.
doi: 10.13204/j.gyjz201006026
Abstract:
A chemical plant was suffered greater damage after a fire hazard. In order to eliminate the hidden danger of the structure，the safety detection and evaluation of structure were taken. Temperature distribution of the fire and temperature of the structural components were deduced，the properties of steel and concrete after fire were tested，and damage extent of the structural components were evaluated. Based on the results，detailed strengthening scheme was put forward. The structure could completely meet the requirements of the bearing capacity and durability after strengthening by the scheme.
A chemical plant was suffered greater damage after a fire hazard. In order to eliminate the hidden danger of the structure，the safety detection and evaluation of structure were taken. Temperature distribution of the fire and temperature of the structural components were deduced，the properties of steel and concrete after fire were tested，and damage extent of the structural components were evaluated. Based on the results，detailed strengthening scheme was put forward. The structure could completely meet the requirements of the bearing capacity and durability after strengthening by the scheme.
2010, 40(6): 118-122.
doi: 10.13204/j.gyjz201006027
Abstract:
A single story industrial building in Xi'an is positioned on a high-filled ground. Because the designeradopted unsuitable ground treatment method，so cracks occurred on the wall and the floor，whose width was about 2.0centimeter inside and outside of the ground which were nearly SN direction; the extensional fracture was mainly on the west of building， which was a serious hidden danger of the building. The scheme of rectifying deviation by underpinning pile was employed after investigation for sake of safety. Based on which the following aspects were investigated: the formula to determine the numbers of underpinning piles for rectifying the leaning building was presented; scheme choice of rectifying deviation，designing method，construction procedure of underpinning pile，jacking monitoring and controlling were introduced in derail; difficult factors and corresponding problems during jacking construction were provided. After reinforcement construction， the settlement of the building tended to stabilization and the normal operation of the workshop was restored. After deformation observation for 6 months，it can be concluded that underpinning pile by manual digging is feasible to reinforce similar structures and project in loess region.
A single story industrial building in Xi'an is positioned on a high-filled ground. Because the designeradopted unsuitable ground treatment method，so cracks occurred on the wall and the floor，whose width was about 2.0centimeter inside and outside of the ground which were nearly SN direction; the extensional fracture was mainly on the west of building， which was a serious hidden danger of the building. The scheme of rectifying deviation by underpinning pile was employed after investigation for sake of safety. Based on which the following aspects were investigated: the formula to determine the numbers of underpinning piles for rectifying the leaning building was presented; scheme choice of rectifying deviation，designing method，construction procedure of underpinning pile，jacking monitoring and controlling were introduced in derail; difficult factors and corresponding problems during jacking construction were provided. After reinforcement construction， the settlement of the building tended to stabilization and the normal operation of the workshop was restored. After deformation observation for 6 months，it can be concluded that underpinning pile by manual digging is feasible to reinforce similar structures and project in loess region.
2010, 40(6): 123-126.
doi: 10.13204/j.gyjz201006028
Abstract:
Due to the change of environmental conditions and so on，basements without considering uplift are often floated and cracked during the construction process or to be used before completion of the project. Therefore，how to analyse and deal with the float of the basement is worthy of being studied and discussed by engineers. Based on a gym，whose beams，columns and slabs of foundation were cracked and floated，the analysis was implemented and the related treatment scheme was proposed to meet the requirements of serviceability. The experience can be used as reference for analyzing and treating similar accidents.
Due to the change of environmental conditions and so on，basements without considering uplift are often floated and cracked during the construction process or to be used before completion of the project. Therefore，how to analyse and deal with the float of the basement is worthy of being studied and discussed by engineers. Based on a gym，whose beams，columns and slabs of foundation were cracked and floated，the analysis was implemented and the related treatment scheme was proposed to meet the requirements of serviceability. The experience can be used as reference for analyzing and treating similar accidents.
2010, 40(6): 127-130.
doi: 10.13204/j.gyjz201006029
Abstract:
In Shenzhen a buildings basement rose up unevenly because of groundwater buoyancy force action，the maximum rising was up to 397 mm，which caused serious damage to structural components. In this paper，the floated reason of the basement and the failure mechanism of the structure were analyzed，and on this basis，the completed permanent anti-buoyant treatment and the structure reinforcement of the basement were carried out，which achieved good economic and social benefits.
In Shenzhen a buildings basement rose up unevenly because of groundwater buoyancy force action，the maximum rising was up to 397 mm，which caused serious damage to structural components. In this paper，the floated reason of the basement and the failure mechanism of the structure were analyzed，and on this basis，the completed permanent anti-buoyant treatment and the structure reinforcement of the basement were carried out，which achieved good economic and social benefits.
