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2012 Vol. 42, No. 7
Display Method:
2012, 42(7): 1-13,73.
doi: 10.13204/j.gyjz201207001
Abstract:
To corporate with the promulgation of Technical Specification for Sinusoidal Web Steel Structures ( CECS290:2011 ), the main provisions in the specification and corresponding backgrounds were introduced, associatedwith the latest research progress of sinusoidal web steel structures. As it has special load-carrying mechanism, thetechnical backgrounds of design provisions for the sinusoidal web member were pointed out, covering the design ofstrength, stiffness, and stability of members and joints. More specifically, the methods for checking of sectionalstrength, local bearing strength, stability of the bearing stiffeners, shear stability of the sinusoidal webs and theoverall stability of the members were involved in this study. A simplified FE model and some simplified formulas forcalculating the deformation of the sinusoidal web members and structures were given, and a joint model fordetermining the bolt force and the thickness of the end-plate in the connections were proposed respectively. Some jointconstruction details in the specification for the sinusoidal web gabled frames were also presented. And some keyissues in the fabrication and erection of the sinusoidal web structures were discussed, including the requirements forthe rolling and welding of the members, the error control techniques and the standards for rust removal, coating andcorrosion proof, and besides, an automatic production line to fabricate the sinusoidal web members was introduced.In addition, the performance of sinusoidal steel plate shear walls, and the compression with flat steel plate shear wallsas well, were introduced briefly.
To corporate with the promulgation of Technical Specification for Sinusoidal Web Steel Structures ( CECS290:2011 ), the main provisions in the specification and corresponding backgrounds were introduced, associatedwith the latest research progress of sinusoidal web steel structures. As it has special load-carrying mechanism, thetechnical backgrounds of design provisions for the sinusoidal web member were pointed out, covering the design ofstrength, stiffness, and stability of members and joints. More specifically, the methods for checking of sectionalstrength, local bearing strength, stability of the bearing stiffeners, shear stability of the sinusoidal webs and theoverall stability of the members were involved in this study. A simplified FE model and some simplified formulas forcalculating the deformation of the sinusoidal web members and structures were given, and a joint model fordetermining the bolt force and the thickness of the end-plate in the connections were proposed respectively. Some jointconstruction details in the specification for the sinusoidal web gabled frames were also presented. And some keyissues in the fabrication and erection of the sinusoidal web structures were discussed, including the requirements forthe rolling and welding of the members, the error control techniques and the standards for rust removal, coating andcorrosion proof, and besides, an automatic production line to fabricate the sinusoidal web members was introduced.In addition, the performance of sinusoidal steel plate shear walls, and the compression with flat steel plate shear wallsas well, were introduced briefly.
2012, 42(7): 14-21,44.
doi: 10.13204/j.gyjz201207002
Abstract:
A H-shaped beam with a sinusoidal corrugated web has a high load-carrying efficiency under bending, butit is still verified to be highly efficient as an axial loaded column by a rational design for the section. This paperfocused on the buckling behavior and corresponding design formula of the sinusoidal corrugated web column loadedaxially. Two specimens axially loaded were tested, and the obtained test results were consistent with those of finiteshell element analysis. Additionally, a comparison of load-carrying efficiency and design economics between the flatand corrugated web columns was also made.
A H-shaped beam with a sinusoidal corrugated web has a high load-carrying efficiency under bending, butit is still verified to be highly efficient as an axial loaded column by a rational design for the section. This paperfocused on the buckling behavior and corresponding design formula of the sinusoidal corrugated web column loadedaxially. Two specimens axially loaded were tested, and the obtained test results were consistent with those of finiteshell element analysis. Additionally, a comparison of load-carrying efficiency and design economics between the flatand corrugated web columns was also made.
2012, 42(7): 22-29.
doi: 10.13204/j.gyjz201207003
Abstract:
The effect of shear deformation in singly-stepped sinusoidal corrugated web columns on the effective lengthfactors is analyzed, and theoretically derived formulation was presented firstly. Compared with approximately TheCode for Design of Steel Structures ( GB 5001 7 2003 ) and the FEA results, it was concluded that the verification ofglobal stability in the singly-stepped sinusoidal corrugated web columns is proposed by combing the effective lengthfactors given by GB 5001 7 2003 with the design formula from Technical Specification for Sinusoidal Web SteelStructures ( CECS 290:201 1 ) which reflects the effect of shear deformation of corrugated web. And the formula forcalculating the lateral deformation of singly-stepped sinusoidal corrugated web columns was given. Finally, thestructural construction details and design of shoulder-beam of singly-stepped column were introduced.
The effect of shear deformation in singly-stepped sinusoidal corrugated web columns on the effective lengthfactors is analyzed, and theoretically derived formulation was presented firstly. Compared with approximately TheCode for Design of Steel Structures ( GB 5001 7 2003 ) and the FEA results, it was concluded that the verification ofglobal stability in the singly-stepped sinusoidal corrugated web columns is proposed by combing the effective lengthfactors given by GB 5001 7 2003 with the design formula from Technical Specification for Sinusoidal Web SteelStructures ( CECS 290:201 1 ) which reflects the effect of shear deformation of corrugated web. And the formula forcalculating the lateral deformation of singly-stepped sinusoidal corrugated web columns was given. Finally, thestructural construction details and design of shoulder-beam of singly-stepped column were introduced.
2012, 42(7): 30-36,165.
doi: 10.13204/j.gyjz201207004
Abstract:
Sinusoidal corrugated web H-shaped members are composed of flanges and sinusoidal webs, and it has ahigher load-carrying efficiency than flat web especially as a beam. Based on the section simplified model of thesinusoidal corrugated web, the bend-carrying capacity and the shearing stability capacity of the sinusoidal corrugatedweb beams were proposed. Formula of beam deflection which considers the shearing deformation of sinusoidalcorrugated web was also presented. Two full scale tests of sinusoidal web members under bending were carried out, and loading process and failure mechanism of the beam were shown. Finite element analysis was used to certify thetest results, and the initial defect of members was also considered. It concludes that all of the test results went wellwith the FEA results, and both of them had confirmed the rationality of the proposed formula mentioned above.
Sinusoidal corrugated web H-shaped members are composed of flanges and sinusoidal webs, and it has ahigher load-carrying efficiency than flat web especially as a beam. Based on the section simplified model of thesinusoidal corrugated web, the bend-carrying capacity and the shearing stability capacity of the sinusoidal corrugatedweb beams were proposed. Formula of beam deflection which considers the shearing deformation of sinusoidalcorrugated web was also presented. Two full scale tests of sinusoidal web members under bending were carried out, and loading process and failure mechanism of the beam were shown. Finite element analysis was used to certify thetest results, and the initial defect of members was also considered. It concludes that all of the test results went wellwith the FEA results, and both of them had confirmed the rationality of the proposed formula mentioned above.
2012, 42(7): 37-44.
doi: 10.13204/j.gyjz201207005
Abstract:
It is common to meet the H-shaped member of sinusoidal webs with openings. Currently, the shear andbend-carrying capacity of H-shaped member of sinusoidal web with circular openings was rarely studied. This paperpresents a finite element analysis, resulting in shearing stress distribution and amplitude on the web with opening.Accordingly an equation to predict the shear-carrying capacity of the web with openings was proposed, based on lots ofFE numerical results. Finally, the bend-carrying capacity and deflection of the beam with web openings was alsoanalyzed, as well as the influence of gaps between openings.
It is common to meet the H-shaped member of sinusoidal webs with openings. Currently, the shear andbend-carrying capacity of H-shaped member of sinusoidal web with circular openings was rarely studied. This paperpresents a finite element analysis, resulting in shearing stress distribution and amplitude on the web with opening.Accordingly an equation to predict the shear-carrying capacity of the web with openings was proposed, based on lots ofFE numerical results. Finally, the bend-carrying capacity and deflection of the beam with web openings was alsoanalyzed, as well as the influence of gaps between openings.
2012, 42(7): 45-54.
doi: 10.13204/j.gyjz201207006
Abstract:
The strength of sinusoidal web I-shaped girders under patch loading is not studied well up to now. It wassummarized the previous research work on plane web girders and trapezoidal corrugated web girders, and thenpresented a systemic study on the patch loading behavior of I-shaped girders with sinusoidal corrugated webs. Failuremodes and the influence of initial geometrical imperfection of web were investigated by nonlinear shell elementanalysis. Based upon parametric studies on sinusoidal corrugated web girders, a simplified design formula forestimating the ultimate strength of the girders under patch loading was proposed. In the case of I-shaped girder oftensubjected to combined patch loading and bending moment, an interaction design formula for predicting its limitstrength was proposed accordingly, and validated by FE numerical results.
The strength of sinusoidal web I-shaped girders under patch loading is not studied well up to now. It wassummarized the previous research work on plane web girders and trapezoidal corrugated web girders, and thenpresented a systemic study on the patch loading behavior of I-shaped girders with sinusoidal corrugated webs. Failuremodes and the influence of initial geometrical imperfection of web were investigated by nonlinear shell elementanalysis. Based upon parametric studies on sinusoidal corrugated web girders, a simplified design formula forestimating the ultimate strength of the girders under patch loading was proposed. In the case of I-shaped girder oftensubjected to combined patch loading and bending moment, an interaction design formula for predicting its limitstrength was proposed accordingly, and validated by FE numerical results.
2012, 42(7): 55-64,178.
doi: 10.13204/j.gyjz201207007
Abstract:
Sinusoidal web H-shaped members are composed of flanges and sinusoidal webs, and are widely used ingabled frames steel structures because of their higher load-carrying efficiency and better economic benefit compared totraditional flat web members. Based on joint forms of the traditional gabled frames structure, and combined with themechanical characteristics of almost zero normal stress on the sinusoidal web section, the new joint forms suitable forsinusoidal web gabled frames were given. The typical end plate connections considering contact between plateelements were analyzed by using FEA, thus a simplified design method of the connection of sinusoidal web gabledframes was proposed. Both joint details and fabrication requirements of the sinusoidal web gabled frames were alsopresented. Finally, a practical application of the new joint forms in the sinusoidal web gabled frames was given, providing a useful reference for the similar projects joint design.
Sinusoidal web H-shaped members are composed of flanges and sinusoidal webs, and are widely used ingabled frames steel structures because of their higher load-carrying efficiency and better economic benefit compared totraditional flat web members. Based on joint forms of the traditional gabled frames structure, and combined with themechanical characteristics of almost zero normal stress on the sinusoidal web section, the new joint forms suitable forsinusoidal web gabled frames were given. The typical end plate connections considering contact between plateelements were analyzed by using FEA, thus a simplified design method of the connection of sinusoidal web gabledframes was proposed. Both joint details and fabrication requirements of the sinusoidal web gabled frames were alsopresented. Finally, a practical application of the new joint forms in the sinusoidal web gabled frames was given, providing a useful reference for the similar projects joint design.
2012, 42(7): 65-68.
doi: 10.13204/j.gyjz201207008
Abstract:
The low carbon sustainable residential evaluation system devotes to saving energy, reducing emission, andoptimizing the living environment, which plays a key role in coping with global warming and the sustainabledevelopment of human. It was introduced and analyzed comprehensively the most representative internationalresidential appraisal systemsBritish Code for Sustainable House, American LEED, Japanese CASBEE, ChineseEvaluation Standard for Green Building and Chinese Ecological Residential Assessment Manual from the aspects ofdevelopment process, evaluation content, evaluation software, evaluation system marketization, public education andso forth. It was also analyze the advantages and limitations of those residential evaluation systems, and put forward theproblems of the present Chinese low carbon sustainable residential assessment system and the measures to improve thefuture low carbon sustainable residential evaluation systems.
The low carbon sustainable residential evaluation system devotes to saving energy, reducing emission, andoptimizing the living environment, which plays a key role in coping with global warming and the sustainabledevelopment of human. It was introduced and analyzed comprehensively the most representative internationalresidential appraisal systemsBritish Code for Sustainable House, American LEED, Japanese CASBEE, ChineseEvaluation Standard for Green Building and Chinese Ecological Residential Assessment Manual from the aspects ofdevelopment process, evaluation content, evaluation software, evaluation system marketization, public education andso forth. It was also analyze the advantages and limitations of those residential evaluation systems, and put forward theproblems of the present Chinese low carbon sustainable residential assessment system and the measures to improve thefuture low carbon sustainable residential evaluation systems.
2012, 42(7): 69-73.
doi: 10.13204/j.gyjz201207009
Abstract:
The recycling use of discarded buildings is a popular topic at present. Detailed research was conducted onmissionary school constructed during the period of the Republic of China: the main building of Seminario, RegionaleHonan-Kaifeng. Construction plans and elevations were plotted through on-the-spot investigation, and based onfirsthand information, it was made a deep and meticulous analysis of the construction ＇s spatial distribution anddecoration, and put forward the feasibility protection scheme. Attention is paid to this building and moreover, protection and utilization are what this research expects.
The recycling use of discarded buildings is a popular topic at present. Detailed research was conducted onmissionary school constructed during the period of the Republic of China: the main building of Seminario, RegionaleHonan-Kaifeng. Construction plans and elevations were plotted through on-the-spot investigation, and based onfirsthand information, it was made a deep and meticulous analysis of the construction ＇s spatial distribution anddecoration, and put forward the feasibility protection scheme. Attention is paid to this building and moreover, protection and utilization are what this research expects.
2012, 42(7): 74-78.
doi: 10.13204/j.gyjz201207010
Abstract:
The factor of frequent value and quasi-permanent value given in the current load codes were determined onthe basis of engineering judgment rather than statistical definition. By establishing the relationships between the ratioof mean time of exceedance to design reference period and the factor of frequent value and quasi-permanent value, thefactor of frequent value and quasi-permanent value for live load and wind load on floor were determind. It was shownthat the factors of the frequent value and the quasi-permanent value for live loads on floor determined in this paper arelarger and smaller than those given in current codes, respectively, and the factor of the frequent value for wind loaddetermined was slightly larger than that provided in current codes.
The factor of frequent value and quasi-permanent value given in the current load codes were determined onthe basis of engineering judgment rather than statistical definition. By establishing the relationships between the ratioof mean time of exceedance to design reference period and the factor of frequent value and quasi-permanent value, thefactor of frequent value and quasi-permanent value for live load and wind load on floor were determind. It was shownthat the factors of the frequent value and the quasi-permanent value for live loads on floor determined in this paper arelarger and smaller than those given in current codes, respectively, and the factor of the frequent value for wind loaddetermined was slightly larger than that provided in current codes.
2012, 42(7): 79-81.
doi: 10.13204/j.gyjz201207011
Abstract:
The specification of the failure probability does not match the value with the actual situation. According tothe fact that the reliability of a structure would be reduced on its ageing with time, which was taken into accourct inthe fuilure probability, and was also an increasing process of changing acceleration, so a new linear increment couldbe used to simulate this process, which conformed to the objective situation to some extent. In the bridge designreference period, the failure probability in the aging phase would be linearly increased by 10% per year, by whichthe modified annual failure probability function was proposed.
The specification of the failure probability does not match the value with the actual situation. According tothe fact that the reliability of a structure would be reduced on its ageing with time, which was taken into accourct inthe fuilure probability, and was also an increasing process of changing acceleration, so a new linear increment couldbe used to simulate this process, which conformed to the objective situation to some extent. In the bridge designreference period, the failure probability in the aging phase would be linearly increased by 10% per year, by whichthe modified annual failure probability function was proposed.
2012, 42(7): 82-85.
doi: 10.13204/j.gyjz201207012
Abstract:
The precise integration method and Wilson- method are combined to compute the structural dynamicequation, and wilson- precise integration method is proposed, and applied to structural seismic time-historyresponse analysis. The method through introducing Wilson- method basic assumptions, the structural dynamicdifferential equations of order reduction, then the application of precise integration method and Newton Cotes formulaof integration not only reduces the matrix of order and avoids the matrix inverse. Finally, some examples are given, the calculation results show that the method has good adaptability to seismic action, and good accuracy and highefficiency, which can be applied in the project.
The precise integration method and Wilson- method are combined to compute the structural dynamicequation, and wilson- precise integration method is proposed, and applied to structural seismic time-historyresponse analysis. The method through introducing Wilson- method basic assumptions, the structural dynamicdifferential equations of order reduction, then the application of precise integration method and Newton Cotes formulaof integration not only reduces the matrix of order and avoids the matrix inverse. Finally, some examples are given, the calculation results show that the method has good adaptability to seismic action, and good accuracy and highefficiency, which can be applied in the project.
2012, 42(7): 86-90.
doi: 10.13204/j.gyjz201207013
Abstract:
Four beams with C1 00 high-strength concrete and HRBF 500 grade rebar and different stirrup ratio weretested, with the shear-span ratio being kept around 3. The development form of the crack and failure process of beamswere observed. According to the data of the test, the shear capacity of beams was analyzed. At last, the experimentalresults were compared with the calculation values by current code. The testing results indicate that the beams with C1 00 high-strength concrete and HRBF 500 grade rebar could work well and its failure modes were similar to theordinary concrete beam. Improving stirrup ratio appropriately was an effective way to improve the shear bearingcapacity and control the diagonal crack development of beams. When shear-span ratio is 3, the current Chinese codeformula used for beam without web reinforcement is not safe, and used for beam with web reinforcement isconservative.
Four beams with C1 00 high-strength concrete and HRBF 500 grade rebar and different stirrup ratio weretested, with the shear-span ratio being kept around 3. The development form of the crack and failure process of beamswere observed. According to the data of the test, the shear capacity of beams was analyzed. At last, the experimentalresults were compared with the calculation values by current code. The testing results indicate that the beams with C1 00 high-strength concrete and HRBF 500 grade rebar could work well and its failure modes were similar to theordinary concrete beam. Improving stirrup ratio appropriately was an effective way to improve the shear bearingcapacity and control the diagonal crack development of beams. When shear-span ratio is 3, the current Chinese codeformula used for beam without web reinforcement is not safe, and used for beam with web reinforcement isconservative.
2012, 42(7): 91-94.
doi: 10.13204/j.gyjz201207014
Abstract:
Rectangular geometric model has been used universally for the numerical simulation of air temperature inlarge space structure under fire. For practical structures, however, in order to meet the function and architecturalmodeling requirements, the geometric shapes of large space building are often with curved surfaces or shell. In thispaper, computer simulation was performed by FDS program for fire cases using the algorithm of fitting circular wallbased on rectangular unit. It was summarized the effect of circular wall on air heating-up process for large-spacestructure under fire. Moreover, the empirical formula of air temperature in large space structure, which consideredthe effect of circular wall under fire, was established by a nonlinear curve-fitting method with MATLAB program.
Rectangular geometric model has been used universally for the numerical simulation of air temperature inlarge space structure under fire. For practical structures, however, in order to meet the function and architecturalmodeling requirements, the geometric shapes of large space building are often with curved surfaces or shell. In thispaper, computer simulation was performed by FDS program for fire cases using the algorithm of fitting circular wallbased on rectangular unit. It was summarized the effect of circular wall on air heating-up process for large-spacestructure under fire. Moreover, the empirical formula of air temperature in large space structure, which consideredthe effect of circular wall under fire, was established by a nonlinear curve-fitting method with MATLAB program.
2012, 42(7): 95-99,90.
doi: 10.13204/j.gyjz201207015
Abstract:
According to the practical engineering of rock deep excavation with a depth about 30 m adjacent to thesubway tunnel in Chongqing, two kinds of supporting scheme were introduced. One was the retaining pile and anchorcable, and the other was the reserved rock wall and the retaining pile. Based on the numerical simulation, the mainmonitored results were analyzed. The result showed that deformation of rock excavation was small; the retaining pileand reserve rock wall could effectively control the displacement of the excavation in rock adjacent to tunnel. The maindeformation of supporting structures concentrated in soil strata in rocky area. The overall stability of the slope couldbe improved by reinforcing the top of slope. The position of the biggest settlement points influenced by the existenceof the adjacent tunnel was corresponding to the vault of tunnels, and the lateral deformation was dominant in thetunnel. The displacement field of the rock would changed owing to the inflnences of continuous media and the changeof tunnel geometric shape, the lateral deformation of the funnel was remarked.
According to the practical engineering of rock deep excavation with a depth about 30 m adjacent to thesubway tunnel in Chongqing, two kinds of supporting scheme were introduced. One was the retaining pile and anchorcable, and the other was the reserved rock wall and the retaining pile. Based on the numerical simulation, the mainmonitored results were analyzed. The result showed that deformation of rock excavation was small; the retaining pileand reserve rock wall could effectively control the displacement of the excavation in rock adjacent to tunnel. The maindeformation of supporting structures concentrated in soil strata in rocky area. The overall stability of the slope couldbe improved by reinforcing the top of slope. The position of the biggest settlement points influenced by the existenceof the adjacent tunnel was corresponding to the vault of tunnels, and the lateral deformation was dominant in thetunnel. The displacement field of the rock would changed owing to the inflnences of continuous media and the changeof tunnel geometric shape, the lateral deformation of the funnel was remarked.
2012, 42(7): 100-104.
doi: 10.13204/j.gyjz201207016
Abstract:
In order to solve the problem which permeation radius calculation formula was rare and its application wasrelatively poor in engineering practice, on the basis of the related assumptions, according to Darcy fixed-rate, newformula of penetration radius was derived. In the derivation, the grouting holes were divided into the ones crossingand not crossing the rock stratum, the angle between the grouting hole and grouting rock stratum, and the viscositytime-varying of the slurry were taken into comprehensive consideration. The formula was applied for the first time to acoal mine in Ningxia, the formula had a good practical value through the engineering practice test. This research maybe a reference to permeation grouting design and quality evaluation.
In order to solve the problem which permeation radius calculation formula was rare and its application wasrelatively poor in engineering practice, on the basis of the related assumptions, according to Darcy fixed-rate, newformula of penetration radius was derived. In the derivation, the grouting holes were divided into the ones crossingand not crossing the rock stratum, the angle between the grouting hole and grouting rock stratum, and the viscositytime-varying of the slurry were taken into comprehensive consideration. The formula was applied for the first time to acoal mine in Ningxia, the formula had a good practical value through the engineering practice test. This research maybe a reference to permeation grouting design and quality evaluation.
2012, 42(7): 105-109,151.
doi: 10.13204/j.gyjz201207017
Abstract:
On cement soil pile treatment of high mineralization lake deposits soft clay foundation in Yinchuan, cubetest specimens with 70. 7mm length of each side were prepared by mixing method under natural water content of softsoil and fixed cement content, strength and deformation of test specimens were determined by hydraulic universalmaterial testing machine, microstructure of cement soil with fly ash content, water content, water cement ratio, cement ratio and age was analyzed by SEM. The - relationship and change in strength of high fly ash cement soilwere studied, the rule and mechanism of strength were revealed. Under high fly ash condition, the strength of cementsoil was increased remarkably. Later age strength growth rate was very high. The optimum ratio of fly ash and cementwas about 3. Filling effect and hydration of fly ash were the main mechanism. The relationship between strength andfly ash content, cement water ratio, water content was approximately linear. The linear correlation between strengthand cement water ratio was the best.
On cement soil pile treatment of high mineralization lake deposits soft clay foundation in Yinchuan, cubetest specimens with 70. 7mm length of each side were prepared by mixing method under natural water content of softsoil and fixed cement content, strength and deformation of test specimens were determined by hydraulic universalmaterial testing machine, microstructure of cement soil with fly ash content, water content, water cement ratio, cement ratio and age was analyzed by SEM. The - relationship and change in strength of high fly ash cement soilwere studied, the rule and mechanism of strength were revealed. Under high fly ash condition, the strength of cementsoil was increased remarkably. Later age strength growth rate was very high. The optimum ratio of fly ash and cementwas about 3. Filling effect and hydration of fly ash were the main mechanism. The relationship between strength andfly ash content, cement water ratio, water content was approximately linear. The linear correlation between strengthand cement water ratio was the best.
2012, 42(7): 110-114.
doi: 10.13204/j.gyjz201207018
Abstract:
A series of shear tests of interface between sandy soil and concrete face was performed by developed largescale simple shear apparatus, and the effect of different single grain sandy soil on mechanical properties of interfacewas studied. By the analysis of test results, the interface thickness and shear displacement of different single grainsandy soil were presented when the sample destroyed. It was shown that there was good linearity of shear strength andnormal stress. In the vertical stress at lower, relation curves of the shear stress and displacement showed strainsoftening; with the increase of vertical stress, the trends of relation curves of the shear stress and displacementshowed more obvious, at this time, relation curves of the shear stress and displacement of interface between differentsingle grain sandy soil and concrete face could be seen as being composed of a curve and a flat line. Lower thevertical stress dilatancy more obvious; with the increase of vertical stress, shear dilatancy weakened, and shear stresswas gradually increasing when shear dilatation appeared.
A series of shear tests of interface between sandy soil and concrete face was performed by developed largescale simple shear apparatus, and the effect of different single grain sandy soil on mechanical properties of interfacewas studied. By the analysis of test results, the interface thickness and shear displacement of different single grainsandy soil were presented when the sample destroyed. It was shown that there was good linearity of shear strength andnormal stress. In the vertical stress at lower, relation curves of the shear stress and displacement showed strainsoftening; with the increase of vertical stress, the trends of relation curves of the shear stress and displacementshowed more obvious, at this time, relation curves of the shear stress and displacement of interface between differentsingle grain sandy soil and concrete face could be seen as being composed of a curve and a flat line. Lower thevertical stress dilatancy more obvious; with the increase of vertical stress, shear dilatancy weakened, and shear stresswas gradually increasing when shear dilatation appeared.
2012, 42(7): 115-118.
doi: 10.13204/j.gyjz201207019
Abstract:
Combined with the engineering practice that dynamic compaction produced vibration destruction inCaofeidian Industrial Zone, the large model test of dynamic compaction vibration was researched and developedindependently. Through two aspects tamper vibration influence scope was determined: first, the vibration accelerationtime history was researched and analysed, the decay laws and attenuation formula of horizontal acceleration in dredgerfill foundation were deduced. Based on the fact that the building would be safe when vibration acceleration was lessthan 0. 1 g, the vibration influence ranges of Caofeidian Region with different ramming energy were determined;second, according to the stress distribution of single pile in CFG piles model, the formula of pile body maximumtension stress of the pile with ramming energy and distance to tamping point was fitted, then according to the ultimatetensile stress of concrete the tamper vibration influence scope was determined.
Combined with the engineering practice that dynamic compaction produced vibration destruction inCaofeidian Industrial Zone, the large model test of dynamic compaction vibration was researched and developedindependently. Through two aspects tamper vibration influence scope was determined: first, the vibration accelerationtime history was researched and analysed, the decay laws and attenuation formula of horizontal acceleration in dredgerfill foundation were deduced. Based on the fact that the building would be safe when vibration acceleration was lessthan 0. 1 g, the vibration influence ranges of Caofeidian Region with different ramming energy were determined;second, according to the stress distribution of single pile in CFG piles model, the formula of pile body maximumtension stress of the pile with ramming energy and distance to tamping point was fitted, then according to the ultimatetensile stress of concrete the tamper vibration influence scope was determined.
2012, 42(7): 119-123.
doi: 10.13204/j.gyjz201207020
Abstract:
A novel expansive agent was prepared by using magnetite and dolomite tailings through certain process.The deformation properties of mortar mixed with expansive agent and fly ash were investigated. Results showed that atthe early age, the expansion speed increased obviously with the increase of hydration temperature, but at the later agethere was no obvious effect on the increase of expansion speed. The dry shrinkage of mortar can be seriouslysuppressed by both expansive agents and fly ash, and dry shrinkage tended stable at the age of 90 d. The temperaturewas an important factor for the restricted expansion of mortar, so the temperature should be strictly controlled whenusing this expansive agent. The regression analysis curve showed that the expansion properties of this expansive agentwere stable through the whole course of hydration, and there was no excessive expansion and retraction.
A novel expansive agent was prepared by using magnetite and dolomite tailings through certain process.The deformation properties of mortar mixed with expansive agent and fly ash were investigated. Results showed that atthe early age, the expansion speed increased obviously with the increase of hydration temperature, but at the later agethere was no obvious effect on the increase of expansion speed. The dry shrinkage of mortar can be seriouslysuppressed by both expansive agents and fly ash, and dry shrinkage tended stable at the age of 90 d. The temperaturewas an important factor for the restricted expansion of mortar, so the temperature should be strictly controlled whenusing this expansive agent. The regression analysis curve showed that the expansion properties of this expansive agentwere stable through the whole course of hydration, and there was no excessive expansion and retraction.
2012, 42(7): 124-127,160.
doi: 10.13204/j.gyjz201207021
Abstract:
The collapse of the existing civil structures would cause the loss of life and property and instability ofsociety. For avoiding these collapses, their indications must be found in time and solved. In this paper, the conceptof weak area in the existing civil structures is proposed based on all kinds of damages in the existing civil structuresand these damages evolution. The weak area is the component or the location in a certain component in which thefailure occurs firstly under the effect of environmental erosion, material deterioration and load variation. The methodto find the weak area in the existing civil structures should be to compare the reduction of load carrying capacity andthe increase of load effect of every component and choose that component in which the load effect is closest to the loadcarrying capacity. Finally, some technical problems to be solved for the analysis of weak area are summarized.
The collapse of the existing civil structures would cause the loss of life and property and instability ofsociety. For avoiding these collapses, their indications must be found in time and solved. In this paper, the conceptof weak area in the existing civil structures is proposed based on all kinds of damages in the existing civil structuresand these damages evolution. The weak area is the component or the location in a certain component in which thefailure occurs firstly under the effect of environmental erosion, material deterioration and load variation. The methodto find the weak area in the existing civil structures should be to compare the reduction of load carrying capacity andthe increase of load effect of every component and choose that component in which the load effect is closest to the loadcarrying capacity. Finally, some technical problems to be solved for the analysis of weak area are summarized.
2012, 42(7): 127-133,174.
doi: 10.13204/j.gyjz201207022
Abstract:
Seismic performance of traditional steel reinforced concrete ( SRC) columns was indistinctively improvedrelative to RC columns in that I and H shaped steel couldn't supply enough constraint for core concrete, henceapplication of the composite columns is limited in high earthquake intensity region, and two new type steel reinforcedconcrete columns are proposed based on this background. Numerical models of five specimens which have beencompleted are established using nonlinear finite element method, and accuracy of the numerical analysis is verified bycomparing ABAQUS results with the experiment of five new columns under low cyclic reversed loading, with focus onhysteretic curves, skeleton curves and stress state of steel. In addition, effects of axial compression ratio, concretestrength grade and stirrup spacing on seismic performance of new columns are analyzed, and limited values of axialcompression ratio for three seismic grades are proposed, which supply a reference for standard revision andengineering calculation.
Seismic performance of traditional steel reinforced concrete ( SRC) columns was indistinctively improvedrelative to RC columns in that I and H shaped steel couldn't supply enough constraint for core concrete, henceapplication of the composite columns is limited in high earthquake intensity region, and two new type steel reinforcedconcrete columns are proposed based on this background. Numerical models of five specimens which have beencompleted are established using nonlinear finite element method, and accuracy of the numerical analysis is verified bycomparing ABAQUS results with the experiment of five new columns under low cyclic reversed loading, with focus onhysteretic curves, skeleton curves and stress state of steel. In addition, effects of axial compression ratio, concretestrength grade and stirrup spacing on seismic performance of new columns are analyzed, and limited values of axialcompression ratio for three seismic grades are proposed, which supply a reference for standard revision andengineering calculation.
2012, 42(7): 134-141.
doi: 10.13204/j.gyjz201207023
Abstract:
Setting transmission member in concrete-filled rectangular steel tube ( CFRST ) column has solved theproblems that steel tube and concrete is difficult to work together for existing CFRST. The elastic foundation beamtheory was applied to concrete-filled steel tube column of setting transmission component, when solving the coefficientof concrete work by analytical method, vertical spring stiffness of steel tube, rotational spring stiffness of steel tube, vertical spring stiffness of concrete were critical. Their solutions were obtained by the finite element method, whichwas more complicated and non-intuitive for practical engineering applications, moreover, was also a certain difficulty.Defining vertical spring stiffness coefficient of steel tube, rotational spring stiffness coefficient of steel tube and verticalspring stiffness coefficient of concrete, and using the finite element simulation, it was analyzed the various factors ofthree spring stiffness coefficients, and obtained the relationships between all influencing factors and three springstiffness coefficients respectively. Considering the coupling effect between various factors, it was modified the fittingequations and had the total fitting equation, and the error analysis was done. The results showed that the total fittingequation of the three spring stiffness coefficients solved solution of the spring stiffness effectively, and provided areliable basis for the further solution of the concrete work-bearing factor.
Setting transmission member in concrete-filled rectangular steel tube ( CFRST ) column has solved theproblems that steel tube and concrete is difficult to work together for existing CFRST. The elastic foundation beamtheory was applied to concrete-filled steel tube column of setting transmission component, when solving the coefficientof concrete work by analytical method, vertical spring stiffness of steel tube, rotational spring stiffness of steel tube, vertical spring stiffness of concrete were critical. Their solutions were obtained by the finite element method, whichwas more complicated and non-intuitive for practical engineering applications, moreover, was also a certain difficulty.Defining vertical spring stiffness coefficient of steel tube, rotational spring stiffness coefficient of steel tube and verticalspring stiffness coefficient of concrete, and using the finite element simulation, it was analyzed the various factors ofthree spring stiffness coefficients, and obtained the relationships between all influencing factors and three springstiffness coefficients respectively. Considering the coupling effect between various factors, it was modified the fittingequations and had the total fitting equation, and the error analysis was done. The results showed that the total fittingequation of the three spring stiffness coefficients solved solution of the spring stiffness effectively, and provided areliable basis for the further solution of the concrete work-bearing factor.
2012, 42(7): 142-146.
doi: 10.13204/j.gyjz201207024
Abstract:
In consideration of shear lag and shear deformation effects, It was proposed an approach of analyzing thestatic characteristics of T-beams generally used in projects. A new warping displacement mode of T-beams was chosento meet the axial self-equilibrium condition for corresponding stress, three generalized displacement functions wereemployed in analyzing static characteristics of the thin-walled T-beams with wide flanges by calculus of variations, thedifferential equations and the corresponding natural boundary conditions of the T-beams are induced based on theminimum potential principle. According to the fundamental differential equations and the corresponding naturalboundary conditions, the static characteristics of thin-walled T-beams are discussed. The finite element solutions werecompared with the analytical solutions and verified the validity of the proposed approach.
In consideration of shear lag and shear deformation effects, It was proposed an approach of analyzing thestatic characteristics of T-beams generally used in projects. A new warping displacement mode of T-beams was chosento meet the axial self-equilibrium condition for corresponding stress, three generalized displacement functions wereemployed in analyzing static characteristics of the thin-walled T-beams with wide flanges by calculus of variations, thedifferential equations and the corresponding natural boundary conditions of the T-beams are induced based on theminimum potential principle. According to the fundamental differential equations and the corresponding naturalboundary conditions, the static characteristics of thin-walled T-beams are discussed. The finite element solutions werecompared with the analytical solutions and verified the validity of the proposed approach.
2012, 42(7): 147-151.
doi: 10.13204/j.gyjz201207025
Abstract:
With regard to a two-span continuous curved bridge with steel box girder, finite element analysis modelwas established by using shell elements, and the stress of steel box girder was computed under different loadingconditions. The reason that results in unevenness of stress distribution at both top and bottom slab of curved steel boxgirder was studied through analysis, and the pattern of stress unevenness was also obtained in this paper. In the end, the unevenness coefficient of stress distribution at both support and mid-span of curved box-girder bridge was definedand a reasonable value was proposed, which may provide a reference for the design of similar bridge structures.
With regard to a two-span continuous curved bridge with steel box girder, finite element analysis modelwas established by using shell elements, and the stress of steel box girder was computed under different loadingconditions. The reason that results in unevenness of stress distribution at both top and bottom slab of curved steel boxgirder was studied through analysis, and the pattern of stress unevenness was also obtained in this paper. In the end, the unevenness coefficient of stress distribution at both support and mid-span of curved box-girder bridge was definedand a reasonable value was proposed, which may provide a reference for the design of similar bridge structures.
2012, 42(7): 152-155,170.
doi: 10.13204/j.gyjz201207026
Abstract:
The test methods and contents for a factory building subjected to fire disaster were introduced, includingsection geometry size, concrete strength, steel strength, and carbonation depth in concrete and so on. The firedamaged structure was appraised according to the test results and calculation. The adapted strengthening methodswere put forward through the specific appraisal results. The damaged columns were respectively strengthened withreinforced concrete, externally bonded steel frame and carbon fiber reinforced polymer. For the damaged beams, demolition replacement, strengthened with externally bonded steel frame and carbon fiber reinforced polymer wereused respectively; for the damaged slabs, the demolition replacement, bottom bonded rebar with shotcrete andexternally bonded carbon fiber reinforced polymer were used. The structure completely resumed its bearing capacityafter strengthening.
The test methods and contents for a factory building subjected to fire disaster were introduced, includingsection geometry size, concrete strength, steel strength, and carbonation depth in concrete and so on. The firedamaged structure was appraised according to the test results and calculation. The adapted strengthening methodswere put forward through the specific appraisal results. The damaged columns were respectively strengthened withreinforced concrete, externally bonded steel frame and carbon fiber reinforced polymer. For the damaged beams, demolition replacement, strengthened with externally bonded steel frame and carbon fiber reinforced polymer wereused respectively; for the damaged slabs, the demolition replacement, bottom bonded rebar with shotcrete andexternally bonded carbon fiber reinforced polymer were used. The structure completely resumed its bearing capacityafter strengthening.
2012, 42(7): 156-160.
doi: 10.13204/j.gyjz201207027
Abstract:
Structure inspection and appraisal of a steel plant's old factory building was carried out, the results showedthat for reinforced concrete members such as columns, roof trusses, trussed girders and roof panels, cracks occurredalong steel bars, peeling of concrete covers and corrosion of steel bars. Also there were many defects of roof bracingsand bracings between columns, and the number of bracings was insufficient. There were many serious securitytroubles to the factory building. A reinforcement design was made based on experiences of earthquake disasters. Thelower concrete columns were strengthened with section enlarging and steel plate, the upper concrete columns, rooftrusses and trussed girders were strengthened with steel frame. The old concrete roof panels were replaced with thesteel ones, and seismic measures were improved. Good result was obtained for the strengthening of the factorybuilding, and the design could be referred by the strengthening of similar structures.
Structure inspection and appraisal of a steel plant's old factory building was carried out, the results showedthat for reinforced concrete members such as columns, roof trusses, trussed girders and roof panels, cracks occurredalong steel bars, peeling of concrete covers and corrosion of steel bars. Also there were many defects of roof bracingsand bracings between columns, and the number of bracings was insufficient. There were many serious securitytroubles to the factory building. A reinforcement design was made based on experiences of earthquake disasters. Thelower concrete columns were strengthened with section enlarging and steel plate, the upper concrete columns, rooftrusses and trussed girders were strengthened with steel frame. The old concrete roof panels were replaced with thesteel ones, and seismic measures were improved. Good result was obtained for the strengthening of the factorybuilding, and the design could be referred by the strengthening of similar structures.
2012, 42(7): 161-165.
doi: 10.13204/j.gyjz201207028
Abstract:
The durability inspection of bridge concrete structures in Rizhao coastal area was carried out. And theinvestigation on cover thickness, carbonation depth and free chloride concentration of bridge concrete was executed.The inspection resulted showed that the concrete cover thickness of bridge structures was less than the designed valueand results in durability problem; the unreasonable structure design, unsuitable construction management, shortagemaintenance and excess load were the main reasons of damage to coastal bridges. Moreover, the ingressive chlorideand carbonation would lead to corrosion of steel bar in bridge structures. And the crystalline salt would result inphysical deterioration of bridge concrete.
The durability inspection of bridge concrete structures in Rizhao coastal area was carried out. And theinvestigation on cover thickness, carbonation depth and free chloride concentration of bridge concrete was executed.The inspection resulted showed that the concrete cover thickness of bridge structures was less than the designed valueand results in durability problem; the unreasonable structure design, unsuitable construction management, shortagemaintenance and excess load were the main reasons of damage to coastal bridges. Moreover, the ingressive chlorideand carbonation would lead to corrosion of steel bar in bridge structures. And the crystalline salt would result inphysical deterioration of bridge concrete.
2012, 42(7): 166-170.
doi: 10.13204/j.gyjz201207029
Abstract:
The settlement and inclination of the pier of existing railway bridge is caused by the upper long-term load, which has been affected the running safety. Geological exploration found that a large karst cave is located under thebridge pier foundation. Based on the catastrophe theory, according to the instability conditions of cave roofs thebearing capacity of the original piles was calculated. On this basis, consolidation strengthening was required for thefoundation by using the method of adding piles and enlarging bearing platform, according to the distribution of karstcave and the geological characteristics. And the proper length of adding piles was provided by theoretical calculation.What is more, the relationship between the length of adding piles and the settlement and inclination of the pier wasanalyzed, based on the numerical simulation software. The results showed that the numerical calculation resultsagreed with those of theoretical calculation. The bearing capacity of the original bridge pier foundation could not meetthe design requirements. The proper length of adding piles was 1 4. 5 m. The settlement and the maximum settlementdifference in lognitudinal direction of the bearing platform with the proper length of adding piles was 6. 9 mm and0. 89 mm respectively under the upper loads.
The settlement and inclination of the pier of existing railway bridge is caused by the upper long-term load, which has been affected the running safety. Geological exploration found that a large karst cave is located under thebridge pier foundation. Based on the catastrophe theory, according to the instability conditions of cave roofs thebearing capacity of the original piles was calculated. On this basis, consolidation strengthening was required for thefoundation by using the method of adding piles and enlarging bearing platform, according to the distribution of karstcave and the geological characteristics. And the proper length of adding piles was provided by theoretical calculation.What is more, the relationship between the length of adding piles and the settlement and inclination of the pier wasanalyzed, based on the numerical simulation software. The results showed that the numerical calculation resultsagreed with those of theoretical calculation. The bearing capacity of the original bridge pier foundation could not meetthe design requirements. The proper length of adding piles was 1 4. 5 m. The settlement and the maximum settlementdifference in lognitudinal direction of the bearing platform with the proper length of adding piles was 6. 9 mm and0. 89 mm respectively under the upper loads.
2012, 42(7): 171-174.
doi: 10.13204/j.gyjz201207030
Abstract:
It was carried out that the researches on technical standard improvement, standardization, transfer station, affiliated engineering design and station space development during architectural design of Xi'an No. 3 metro line. Thesuccessful experience in the deisgn of the constructed metro stations and those under construction at home was alsoused for the architectural design, which compensated the deficiency of the architectural design of the past metro lines, thus resulting in standardization and unity of the architectural design of Xi'an No. 3 metro line. Meanwhile a rationaldevelopment of station space was also done during the erchitectural design, which provided support for the sustainabledevelopment of metro construction in Xi'an region.
It was carried out that the researches on technical standard improvement, standardization, transfer station, affiliated engineering design and station space development during architectural design of Xi'an No. 3 metro line. Thesuccessful experience in the deisgn of the constructed metro stations and those under construction at home was alsoused for the architectural design, which compensated the deficiency of the architectural design of the past metro lines, thus resulting in standardization and unity of the architectural design of Xi'an No. 3 metro line. Meanwhile a rationaldevelopment of station space was also done during the erchitectural design, which provided support for the sustainabledevelopment of metro construction in Xi'an region.
2012, 42(7): 175-178.
doi: 10.13204/j.gyjz201207031
Abstract:
In the past few years, low carbon has been valued by the world, it was author proposed low-carbon conceptplanning of Laowo Town according to urban planning professional knowledge. It was recognized that low-carbon plansshould be started from the following aspects: urban functional and industry development positioning, reasonable roadtraffic planning and layout of urban land, the special planning of infrastructure and low carbon planning ofarchitecture etc.
In the past few years, low carbon has been valued by the world, it was author proposed low-carbon conceptplanning of Laowo Town according to urban planning professional knowledge. It was recognized that low-carbon plansshould be started from the following aspects: urban functional and industry development positioning, reasonable roadtraffic planning and layout of urban land, the special planning of infrastructure and low carbon planning ofarchitecture etc.
2012, 42(7): 179-182,141.
doi: 10.13204/j.gyjz201207032
Abstract:
By producing 3D, 4D and even nD parametric models, the technique of building information modeling( BIM ) offers a platform for all participants of a project to enhance communication and cooperation in entire life cycleof a project to realize greater visualization effect, shorter schedules, improved construction methods and better costcontrol. This article aims to describe the BIM modeling process by taking a realistic construction project＇s BIM 3D and4D modeling for example, it is expected to provide a reference for the popularization of BIM application in China.
By producing 3D, 4D and even nD parametric models, the technique of building information modeling( BIM ) offers a platform for all participants of a project to enhance communication and cooperation in entire life cycleof a project to realize greater visualization effect, shorter schedules, improved construction methods and better costcontrol. This article aims to describe the BIM modeling process by taking a realistic construction project＇s BIM 3D and4D modeling for example, it is expected to provide a reference for the popularization of BIM application in China.
