Cave-in failure is apt to occur in joints of trusses made of square hollow sections. In order to turn the failure mode into a strength failure mode of joint members, the idea is proposed that the chord of the truss is...Cave-in failure is apt to occur in joints of trusses made of square hollow sections. In order to turn the failure mode into a strength failure mode of joint members, the idea is proposed that the chord of the truss is grouted to increase the cave-in beating capacity of a hollow tube chord. An experiment of eight specimens of N- joints made of grout-filled square steel tubes is performed. Based on the experimental study, the geometrical parameters of specimens are analyzed, and the effects of the confinement index ε, the spacing between the two web members g and the ratio of side length of the vertical web member to that of the chord β on the behavior of specimens are investigated through simulation analysis by simulation analyses, the mechanical properties and the failure an ANSYS program. Based on the test results and modes of this kind of joints are analyzed and the formulae to predict the ultimate bearing capacities corresponding to different failure modes are developed. The ultimate bearing capacity of compressive N-joints is calculated in accordance with the cave-in failure mode of a chord member; the ultimate bearing capacity of tension N-joints is calculated in accordance with the punchingshear failure mode; the ultimate bearing capacity of a chord member is calculated in accordance with the shear failure mode in normal sections.展开更多
As an important structural member in self-supporting concrete floor during construction,encased steel truss-concrete composite beam has brilliant prospect in outer-jacketing structures for adding stories or mega frame...As an important structural member in self-supporting concrete floor during construction,encased steel truss-concrete composite beam has brilliant prospect in outer-jacketing structures for adding stories or mega frame structures.Compared with encased angle truss,encased round steel tube truss can facilitate layout of itself in column and facilitate layout and anchorage of prestressed reinforcement placed horizontally.N-joint is wildly used in encased steel truss.For cave-in failure easily occurs in hollow steel-tube joint,the idea that the chord is grouted to increase cave-in bearing capacity of hollow tube is proposed.Test results of 8 grouted-round-steel-tube N-joints from the beginning of loading to failure are reported.Mechanical property and failure mode of this kind of truss joint are analyzed,and the formulas of ultimate bearing capacity of the joint corresponding to different failure modes are established.All these can provide basic data for spreading encased steel truss-concrete composite beam.展开更多
Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each spec...Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Mo...展开更多
海上浮式生产装置(floating production unit,FPU)上部生产模块结构中包含着大量的非管节点,而此类节点在其服役期内易发生疲劳失效。相较于一般管节点,非管节点结构型式更为复杂,其疲劳评估更为困难,通常无法利用海工结构设计软件进行...海上浮式生产装置(floating production unit,FPU)上部生产模块结构中包含着大量的非管节点,而此类节点在其服役期内易发生疲劳失效。相较于一般管节点,非管节点结构型式更为复杂,其疲劳评估更为困难,通常无法利用海工结构设计软件进行直接计算分析。为了实现非管节点疲劳寿命快速计算,该文采用S-N曲线法与整体结构分析和局部有限元分析相结合的方法,对非管节点的疲劳进行了研究,并形成了一套FPU上部生产模块非管节点疲劳预测方法。基于FPU上部三甘醇(triethylene glycol,TEG)处理模块设计实例,采用上述方法对其疲劳寿命进行评估,验证了该计算方法的适用性。结果显示,在考虑安全系数的情况下,TEG模块非管节点的最小疲劳寿命为20.11年,满足设计规范要求。该模块通过了美国船级社(American Bureau of Shipping,ABS)审查,完成陆地建造和交付,并成功应用于印尼马杜拉海域,证明了该非管节点疲劳预测方法的可靠性,相关研究结论可为类似非管节点结构的疲劳分析提供借鉴。展开更多
基金The National Natural Science Foundation of China(No50178026)Program for New Century Excellent Talents in University+1 种基金the Key Technologies R & D Program of Heilongjiang Province(NoGC04A609)the Key Technologies R & D Program of Harbin City(No2004AA9CS187)
文摘Cave-in failure is apt to occur in joints of trusses made of square hollow sections. In order to turn the failure mode into a strength failure mode of joint members, the idea is proposed that the chord of the truss is grouted to increase the cave-in beating capacity of a hollow tube chord. An experiment of eight specimens of N- joints made of grout-filled square steel tubes is performed. Based on the experimental study, the geometrical parameters of specimens are analyzed, and the effects of the confinement index ε, the spacing between the two web members g and the ratio of side length of the vertical web member to that of the chord β on the behavior of specimens are investigated through simulation analysis by simulation analyses, the mechanical properties and the failure an ANSYS program. Based on the test results and modes of this kind of joints are analyzed and the formulae to predict the ultimate bearing capacities corresponding to different failure modes are developed. The ultimate bearing capacity of compressive N-joints is calculated in accordance with the cave-in failure mode of a chord member; the ultimate bearing capacity of tension N-joints is calculated in accordance with the punchingshear failure mode; the ultimate bearing capacity of a chord member is calculated in accordance with the shear failure mode in normal sections.
基金Sponsored by the New Century Excellent Talents in University(Grant No.290)Heilongjiang Key Program on Science and Technology(Grant No.GC04A609)Harbin Key Program on Science and Technology(Grant No.2004AA9CS187).
文摘As an important structural member in self-supporting concrete floor during construction,encased steel truss-concrete composite beam has brilliant prospect in outer-jacketing structures for adding stories or mega frame structures.Compared with encased angle truss,encased round steel tube truss can facilitate layout of itself in column and facilitate layout and anchorage of prestressed reinforcement placed horizontally.N-joint is wildly used in encased steel truss.For cave-in failure easily occurs in hollow steel-tube joint,the idea that the chord is grouted to increase cave-in bearing capacity of hollow tube is proposed.Test results of 8 grouted-round-steel-tube N-joints from the beginning of loading to failure are reported.Mechanical property and failure mode of this kind of truss joint are analyzed,and the formulas of ultimate bearing capacity of the joint corresponding to different failure modes are established.All these can provide basic data for spreading encased steel truss-concrete composite beam.
基金Supported by National Natural Science Foundation of China (No.50608054)
文摘Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Mo...
文摘海上浮式生产装置(floating production unit,FPU)上部生产模块结构中包含着大量的非管节点,而此类节点在其服役期内易发生疲劳失效。相较于一般管节点,非管节点结构型式更为复杂,其疲劳评估更为困难,通常无法利用海工结构设计软件进行直接计算分析。为了实现非管节点疲劳寿命快速计算,该文采用S-N曲线法与整体结构分析和局部有限元分析相结合的方法,对非管节点的疲劳进行了研究,并形成了一套FPU上部生产模块非管节点疲劳预测方法。基于FPU上部三甘醇(triethylene glycol,TEG)处理模块设计实例,采用上述方法对其疲劳寿命进行评估,验证了该计算方法的适用性。结果显示,在考虑安全系数的情况下,TEG模块非管节点的最小疲劳寿命为20.11年,满足设计规范要求。该模块通过了美国船级社(American Bureau of Shipping,ABS)审查,完成陆地建造和交付,并成功应用于印尼马杜拉海域,证明了该非管节点疲劳预测方法的可靠性,相关研究结论可为类似非管节点结构的疲劳分析提供借鉴。
文摘为研究承载型60°斜十字全熔透焊接接头(oblique cruciform full-penetration welded joints,OCFWJs)局部应力分布及疲劳性能,设计3个试验模型完成3种名义应力幅水平下的疲劳试验,得到试件疲劳破坏时的循环次数.利用ABAQUS软件建立60°OCFWJs有限元模型,计算得到焊趾处热点正应力、热点剪应力及等效热点应力.基于规范中的名义应力S-N曲线和热点应力S-N曲线,分别采用名义主应力法、等效热点应力法和相互作用方程方法对拉—剪联合作用下60°OCFWJs疲劳寿命进行了评估.结果表明,采用名义应力幅、名义拉应力幅或名义剪应力幅均无法对60°OCFWJs疲劳寿命进行可靠评估.依据国际焊接学会(International Institute of Welding,IIW)规范无论采用热点拉应力幅或热点剪应力幅也无法对60°OCFWJs疲劳寿命进行可靠评估.按欧洲钢结构设计规范Eurocode3相互作用方程方法预测的疲劳寿命远低于试验值,按等效热点应力方法预测的疲劳寿命与试验值符合良好.
