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Design Technology of Continuous Beam-Arch Combination Bridges
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作者 Maozhao Yang 《Journal of Architectural Research and Development》 2023年第2期6-10,共5页
In this paper,a research was conducted on the design technology of continuous beam-arch composite bridges.A brief introduction is given on the of continuous beam-arch composite bridges,its basic mechanical characteris... In this paper,a research was conducted on the design technology of continuous beam-arch composite bridges.A brief introduction is given on the of continuous beam-arch composite bridges,its basic mechanical characteristics is analyzed,and three aspects of design technology is studied,which are rise-span ratio,stiffness ratio,and bridge deck cracking.This article acts as a reference for relevant design units in China to improve the design of continuous beam-arch combination bridges. 展开更多
关键词 Continuous beam-arch combination bridge design Analysis of rise-span ratio bridge deck cracking
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Analysis on influence of seismic travelling wave effect on semi-active control for long-span rigid-continuous bridge 被引量:1
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作者 亓兴军 李小军 周国良 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2006年第2期199-206,共8页
The analysis approach of semi-active control for long-span rigid-continuous bridge under seismic travelling wave input is established. Magnetorheological dampers are set on the positions of the bridge beatings. The se... The analysis approach of semi-active control for long-span rigid-continuous bridge under seismic travelling wave input is established. Magnetorheological dampers are set on the positions of the bridge beatings. The semi-active control calculation and analysis are performed for a five-span rigid-continuous bridge under seismic travelling waves with different apparent surface velocities. The results indicate that travelling wave effect remarkably influences the uncontrolled seismic responses, the semi-active control seismic responses and vibration control effects for the long-span rigid-continuous bridge. It is disadvantageous to the responses of the beams and the piers under the travelling wave input with lower apparent surface velocity, and travelling wave effect can decrease the vibration control effects evidently. Therefore, the travelling wave effect should be considered for the selection of the parameter values of semi-active control system in order to get the designing control effect. 展开更多
关键词 travelling wave effect semi-active control long-span rigid-continuous bridge magnetorheoiogicai damper
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Effects of bridge combined internal fixation system internal fixation on fracture healing and shoulder joint function in elderly patients with displaced midshaft clavicle fractures 被引量:1
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作者 Wang Guang-Xin Xiao Wan-Jun +1 位作者 Wang Chen Liang Qing-Wei 《Journal of Hainan Medical University》 2019年第18期35-39,共5页
Objective:To compare the clinical therapeutic effect of bridge combined internal fixation system and locking compression plate internal fixation in the treatment of displaced midshaft clavicle fractures by emphaticall... Objective:To compare the clinical therapeutic effect of bridge combined internal fixation system and locking compression plate internal fixation in the treatment of displaced midshaft clavicle fractures by emphatically observing fracture healing and shoulder joint function.Methods:Totally 44 elderly patients with Robinson type 2B displaced midshaft clavicle fractures were included from the Department of Orthopaedics,Shenyang Fourth People's Hospital during February 2016 and December 2018,including 23 males and 21 females,mean age(69.8±10.2)years old.The patients were divided into a bridge combined internal fixation system group(bridge group,n=22)and a locking compression plate internal fixation group(plate group,n=22)according to the internal fixation methods.The operation time,intraoperative blood loss,fracture healing time,and postoperative complications were recorded.At 12 months after surgery,the shoulder joint Constant-Murley score and DASH score were used to assess the recovery of joint function.The serum levels of bone turnover biochemical markers procollagen I N-terminal peptide(P1NP),cross-linked Carboxy-terminal telopeptide of typeⅠcollagen(CTX-I),and osteoblast specific factor(OSF)were measured before and 3 months after surgery.Results:The operation time,intraoperative blood loss and fracture healing time of the bridge group were significantly shorter than those of the plate group(P<0.05).Constant scores and DASH scores in the bridge group were significantly better than those of the plate group at 12 months after surgery(P<0.05).Serum levels of CTX-I was significantly decreased,while the P1NP and OSF were significantly increased compared with before surgery in the both groups(P<0.05),and the changes were more obvious in the bridge group(P<0.05).The incidence of complications was similar between the two groups(P<0.05).Conclusion:Compared with the locking plate system,the bridge combined internal fixation system can effectively improve the operation efficiency,have more benefits on fracture healing,better promote the recovery of patients'function,and reduce the failure rate of internal fixation,thus providing a better choice to treat displaced midshaft clavicle fractures by intraoperative internal fixation. 展开更多
关键词 bridge combined INTERNAL FIXATION Locking plate old age Mid-clavicular displacement FRACTURE INTERNAL FIXATION FRACTURE healing shoulder function Bone turnover
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PSC Bridge Subjected to Combined Post Tension and Post Compression—A Case Study
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作者 Sujith Shetty Sundar Suraj Sathyanrayana Rao 《World Journal of Engineering and Technology》 2018年第4期767-779,共13页
Starting from the ideas of Conventional Post Tensioning we present a heuristic argument of advantages of combined actions of post compression along with post tensioned technique for a PSC member through a Design Examp... Starting from the ideas of Conventional Post Tensioning we present a heuristic argument of advantages of combined actions of post compression along with post tensioned technique for a PSC member through a Design Example. Our aim was to assess the characterization of a pre stressed member if it was?to be under the Load effects of post compressing a bar with post tensioned method through hydraulic jacks as the reinforcements in the tensioned zone of conventional PSC bridge were to be compressed in order to induce internal tensile stress similar to internal compressive stresses developed due to conventional post tensioned design. The results ultimately concluded that post compressing a Slender bar by a pre stressing force in the compression zone by a value equal to 0.1?-?0.7 times the pre stressing force in the tension zone would eventually lead to cancelling out of tensile and compressive stresses, thereby forming the desired section which is comparatively smaller in size but can account for sustainability. The anchorage at the top end was?provided by special slender steel rods to eliminate the compressive stresses. All the dead loads?were?counteracted by the action of prestress and the bridge section was able to carry only live load which is deduced through examples in the article. 展开更多
关键词 combined POST Tension and POST Compression PRESTRESS Concrete Design of bridgeS
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Segmental Bridges under Combined Torsion, Bending and Shear
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作者 黄真 刘西拉 《Journal of Shanghai Jiaotong university(Science)》 EI 2003年第2期111-114,共4页
Segmental bridges with unbonded prestressed tendons have some advantages, such as the weather independence and the corrosion protection of prestressing tendons. This paper analyzed the behavior of a prestressed segmen... Segmental bridges with unbonded prestressed tendons have some advantages, such as the weather independence and the corrosion protection of prestressing tendons. This paper analyzed the behavior of a prestressed segmental bridge with unbonded tendons under combined loading of torsion, bending and shear. According to the experiment research, a modified skew bending model was developed to calculate the bearing capacity of segmental bridges subjected to combined bending, shear and torsion. The finite element method was used to investigate the deflection behaviors of such structure, also to check the theoretical model. The theoretical and FEM research results were compared favorably with the test results from Technical University of Braunschweig, Germany. Finally, suggestion for the design and construction of segmental bridges with external prestressing was made. 展开更多
关键词 unbonded prestressing tendons segmental bridge combined loading of torsion bending and shear
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Optimizing selection of bridge raft based on fuzzy matter-element model and combination weighting
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作者 Li Feng Shao Fei +1 位作者 Wang Jianping Li Zhigang 《Engineering Sciences》 EI 2012年第1期61-64,96,共5页
It' s a necessary selection to support the maneuver across Yangtze River by floating bridge constructed by portable steel bridge and civilian ships. It is a comprehensive index for the scheme of bridge raft, containi... It' s a necessary selection to support the maneuver across Yangtze River by floating bridge constructed by portable steel bridge and civilian ships. It is a comprehensive index for the scheme of bridge raft, containing a variety of technical factors and uncertainties. The optimization is the selection in the constructing time, quantity of equipments and man power. Based on the calculation result of bridge rafts, an evaluating system is established, consisting of index of spacing between interior bays, raft length, truss numbers, operation difficulty and maximal bending stress. A fuzzy matter element model of optimizing selection of bridge rafts was built up by combining quantitative analysis with qualitative analysis. The method of combination weighting was used to calculate the value of weights index to reduce the subjective randomness. The sequence of schemes and the optimization resuh were gained finally based on euclid approach degree. The application result shows that it is simple and practical. 展开更多
关键词 bridge raft optimizing selection fuzzy matter-element combination weighting euclid approach degree
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Developments and Prospects of Long-Span High-Speed Railway Bridge Technologies in China 被引量:61
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作者 Shunquan Qin Zongyu Gao 《Engineering》 SCIE EI 2017年第6期787-794,共8页
With the rapid developments of the high-speed railway in China, a great number of long-span bridges have been constructed in order to cross rivers and gorges. At present, the longest main span of a constructed high-sp... With the rapid developments of the high-speed railway in China, a great number of long-span bridges have been constructed in order to cross rivers and gorges. At present, the longest main span of a constructed high-speed railway bridge is only 630 m. The main span of Hutong Yangtze River Bridge and of Wufengshan Yangtze River Bridge, which are under construction, will be much longer, at 1092 m each. In order to overcome the technical issues that originate from the extremely large dead loading and the relatively small structural stiffness of long-span high-speed railway bridges, many new technologies in bridge construction, design, materials, and so forth have been developed. This paper carefully reviews progress in the construction technologies of multi-function combined bridges in China, including com- bined highway and railway bridges and multi-track railway bridges. Innovations and practices regarding new types of bridge and composite bridge structures, such as bridges with three cable planes and three main trusses, inclined main trusses, slab-truss composite sections, and steel-concrete composite sections, are introduced. In addition, investigations into high-performance materials and integral fabrication and erection techniques for long-span railway bridges are summarized. At the end of the paper, prospects for the future development of long-span high-speed railwav bridges are provided. 展开更多
关键词 High-speed railway Long-span bridges Multi-function combined bridges High-performance materials Spatial structures with three cable planes Integral fabrication
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Design, Calculation and Model Test of Zhongshan Bridge
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作者 李永河 张俊平 黄道沸 《Journal of Southwest Jiaotong University(English Edition)》 2004年第1期49-55,共7页
Zhongshan Bridge is a kind of steel arch bridge with a particular space-combined structure. The rationality of design, accuracy of theoretical calculation and reliability of transportation were studied. Its design, FE... Zhongshan Bridge is a kind of steel arch bridge with a particular space-combined structure. The rationality of design, accuracy of theoretical calculation and reliability of transportation were studied. Its design, FEM calculation of stresses and strains, and model test were introduced in detail. The theoretical analysis and model test verified that the design was reliable and safe. The simulated stresses, rigidity and stability, which are based on the selected loading system and cross-section geometry, satisfy the related design standards. Some of the issues that need to be considered in the real bridge construction were also discussed. 展开更多
关键词 Space-combined structure Steel arch bridge FEM Model test
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SFCC现场导热系数与温度场实测及预测方法研究 被引量:1
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作者 牛艳伟 匡笑艳 +2 位作者 郑军涛 党王辉 汤颖颖 《建筑材料学报》 EI CAS CSCD 北大核心 2024年第3期245-252,282,共9页
为确定钢纤维页岩陶粒混凝土(SFCC)现场实际的导热系数,与桥面板施工同步制作了不同钢纤维体积分数的SFCC试件,采用热板法进行测定,校核并扩展了导热系数预测公式,并且对高温沥青摊铺时SFCC桥面板的温度场进行了实测和数值模拟.结果表明... 为确定钢纤维页岩陶粒混凝土(SFCC)现场实际的导热系数,与桥面板施工同步制作了不同钢纤维体积分数的SFCC试件,采用热板法进行测定,校核并扩展了导热系数预测公式,并且对高温沥青摊铺时SFCC桥面板的温度场进行了实测和数值模拟.结果表明:环境湿度为67%时,SFCC的实测导热系数为0.915~1.409 W/(m·K),增加钢纤维体积分数可提高SFCC导热系数;考虑湿度和钢纤维影响后的扩展Maxwell公式预测值与实测值吻合良好;高温沥青摊铺时桥面板SFCC混凝土内的温度梯度可达20.5℃,超过规范日温差,采用数值模拟可有效计算桥面板温度场. 展开更多
关键词 钢纤维 页岩陶粒混凝土 组合桥面 导热系数 高温沥青摊铺温度场
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超长大跨度公铁合建桥梁结构体系研究 被引量:1
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作者 王小飞 《铁道标准设计》 北大核心 2024年第1期87-95,共9页
新建甬舟铁路西堠门公铁两用大桥连接金塘岛和册子岛,桥位处海域宽2.7 km,最大水深93 m,地形复杂,桥梁设计难度大。为研究超长大跨度公铁合建桥梁合理结构体系,结合地形地质条件,选取主跨1500 m悬索桥、斜拉桥及斜拉悬索协作体系3种桥... 新建甬舟铁路西堠门公铁两用大桥连接金塘岛和册子岛,桥位处海域宽2.7 km,最大水深93 m,地形复杂,桥梁设计难度大。为研究超长大跨度公铁合建桥梁合理结构体系,结合地形地质条件,选取主跨1500 m悬索桥、斜拉桥及斜拉悬索协作体系3种桥型方案,对上部结构设计进行详细介绍,并从静力性能、动力性能、经济性能等方面对不同结构体系进行对比分析。研究表明:(1)与斜拉体系相比,协作体系桥可减小30%~50%的主梁内力和60%的桥塔内力,一定程度上解决了加劲梁承受巨大轴压力造成屈曲问题,并有效减小了桥塔规模;(2)与悬索桥相比,协作体系可减小50%的主缆内力,主缆钢丝和锚碇的工程量相应减小,施工难度得以降低,同时协作体系扭转频率更高,降低了结构在较低风速下发生涡激振动的可能性;(3)斜拉悬索协作体系能够充分发挥斜拉结构和悬索结构的组合优势,实现超大跨度的同时具有较大的纵向刚度和竖向刚度,满足铁路行车对结构刚度的要求;(4)对于主跨1500 m级超长大跨度公铁合建桥梁,斜拉悬索协作体系经济性更好。 展开更多
关键词 超长大跨度公铁合建桥 斜拉悬索协作体系 斜拉桥 悬索桥 桥梁结构体系
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四主缆大跨悬索桥抗震性能分析及减震措施优化 被引量:1
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作者 刘志文 魏祎博 +4 位作者 王连华 丁少凌 谢功元 谢学鑫 陈政清 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第3期8-19,共12页
以燕矶长江大桥为工程背景,首先,采用动力非线性时程法分析了燕矶长江大桥抗震性能,并研究了设置电涡流-摩擦组合型阻尼器和黏滞阻尼器对大跨悬索桥抗震性能的影响;然后,对附加电涡流-摩擦组合型阻尼器摩擦力、阻尼系数和阻尼指数开展... 以燕矶长江大桥为工程背景,首先,采用动力非线性时程法分析了燕矶长江大桥抗震性能,并研究了设置电涡流-摩擦组合型阻尼器和黏滞阻尼器对大跨悬索桥抗震性能的影响;然后,对附加电涡流-摩擦组合型阻尼器摩擦力、阻尼系数和阻尼指数开展了参数敏感性分析;最后,从耗能角度分析地震作用下电涡流-摩擦组合型阻尼器减震特点.结果表明:在E2地震作用下,桥塔关键截面抗弯能力均大于弯矩需求;在“纵向+竖向”地震作用下梁端纵向位移较大.设置塔梁处纵桥向阻尼器后,可有效降低主桥梁端纵向位移;增大摩擦力、阻尼系数与降低阻尼指数均可提升梁端纵向地震响应的控制效果,但参数变化对桥塔控制截面的地震响应影响较小.阻尼系数较大时,电涡流阻尼主导了电涡流-摩擦组合型阻尼器耗能,相较于黏滞阻尼器,电涡流-摩擦组合型阻尼器对梁端纵向位移控制效果更好. 展开更多
关键词 四主缆大跨悬索桥 抗震性能 非线性时程分析 黏滞阻尼器 电涡流-摩擦组合型阻尼器
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D-S理论和Markov链组合的桥梁性能退化预测研究
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作者 杨国俊 田里 +2 位作者 唐光武 毛建博 杜永峰 《应用数学和力学》 CSCD 北大核心 2024年第4期416-428,共13页
为准确预测桥梁性能退化,考虑到数据随机性和微小扰动发生状态跳跃,提出了一种D-S(Dempster-Shafer)证据理论和Markov链组合的桥梁性能退化组合预测模型和性能退化率的概念.该模型基于指数平滑(exponential smoothing,ES)方法获得新的... 为准确预测桥梁性能退化,考虑到数据随机性和微小扰动发生状态跳跃,提出了一种D-S(Dempster-Shafer)证据理论和Markov链组合的桥梁性能退化组合预测模型和性能退化率的概念.该模型基于指数平滑(exponential smoothing,ES)方法获得新的预测数据序列,并利用Markov链和D-S理论不断进行优化,从而实现桥梁性能退化的组合预测.实际工程的应用结果表明:性能退化率可以直观地表征在梁性能退化的速度.其次,该模型的平均相对误差为1.54%,较于回归、灰色和模糊加权Markov链模型,精度分别提高了1.11%,0.88%和2.8%,而后验差比值为0.242,小于0.35;模型的标准差为9.021,相比其他模型分别减小了3.978,3.405和7.500,而变异系数为0.109,均小于其他模型,验证了组合预测模型在精度和稳定性方面的优越性,可为在役桥梁结构性能退化预测与维护提供理论基础. 展开更多
关键词 桥梁工程 性能退化预测 D-S证据理论 MARKOV链 组合预测模型 桥梁性能退化率
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大跨铁路混凝土梁矮塔斜拉桥结构体系研究
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作者 刘晓春 符应文 +2 位作者 李海华 谢腾飞 韦国华 《桥梁建设》 EI CSCD 北大核心 2024年第4期134-140,共7页
为研究不同结构体系对大跨铁路混凝土梁矮塔斜拉桥力学性能的影响,并寻求最优的结构体系,以崇凭铁路上金左江双线特大桥为背景,采用MIDAS Civil和ANSYS软件建立主桥有限元模型及车-轨-桥耦合动力学模型,对半飘浮体系、刚构体系、塔梁固... 为研究不同结构体系对大跨铁路混凝土梁矮塔斜拉桥力学性能的影响,并寻求最优的结构体系,以崇凭铁路上金左江双线特大桥为背景,采用MIDAS Civil和ANSYS软件建立主桥有限元模型及车-轨-桥耦合动力学模型,对半飘浮体系、刚构体系、塔梁固结体系和塔梁固结-刚构组合(高墩塔墩梁固结、矮墩纵向设置双排活动支座)体系方案进行比选,分析典型工况下主桥的静、动力特性。结果表明:在列车活载和温度作用下,采用塔梁固结-刚构组合体系的桥梁受力性能良好,采用较小的梁高即可满足桥梁结构的刚度要求;CRH2列车编组通过时不同结构体系的桥梁结构和列车编组的动力响应值均满足要求,考虑温度变形影响时不同结构体系对列车运行的安全性和舒适性的影响较小。基于力学性能计算结果,上金左江双线特大桥主桥最终采用塔梁固结-刚构组合体系。 展开更多
关键词 铁路桥 矮塔斜拉桥 结构体系 塔梁固结-刚构组合体系 静力性能 动力性能 有限元法
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马鞍山长江公铁大桥Z3号桥塔施工关键技术 被引量:1
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作者 潘博 李维 刘爱林 《世界桥梁》 北大核心 2024年第2期29-35,共7页
巢马城际铁路马鞍山长江公铁大桥主航道桥为(112+392+2×1120+392+112)m三塔钢桁梁斜拉桥,Z3号桥塔为超高多肢钢-混组合塔,高308 m。上塔柱钢结构高87.5 m,分13个吊装节段,最重505 t;中、下塔柱混凝土结构高217.5 m,分38个节段液压... 巢马城际铁路马鞍山长江公铁大桥主航道桥为(112+392+2×1120+392+112)m三塔钢桁梁斜拉桥,Z3号桥塔为超高多肢钢-混组合塔,高308 m。上塔柱钢结构高87.5 m,分13个吊装节段,最重505 t;中、下塔柱混凝土结构高217.5 m,分38个节段液压爬模施工;钢-混结合段高3 m,内部采用PBL键+剪力钉+高强度钢锚杆+高强度混凝土结构形式。在中塔柱设置钢管临时横撑控制塔柱线形及应力;下横梁采用落地支架法分层施工,与对应塔柱同步浇筑;钢-混结合段混凝土采用C60细石补偿收缩混凝土+高强度灌浆料,保证了混凝土施工质量;采用工厂“2+1”立体匹配制造、“提升站+运输栈桥”钢塔节段转运等技术,并研制15000 t•m超大型塔吊,实现了钢塔柱大节段的制造、整体滩地运输和吊装;钢塔节段间采用栓焊组合连接形式,通过设置工艺隔板、双面坡口等措施控制了钢塔焊接变形;利用定位桁架临时锁定钢塔合龙段实现了钢塔的精确合龙,定位桁架受力及变形均满足要求。 展开更多
关键词 斜拉桥 钢-混组合桥塔 超高多肢 钢-混结合段 整体吊装 钢塔合龙 栓焊组合连接 施工技术
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钢桁梁断面形式对公铁两用桥上列车气动特性影响
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作者 何旭辉 肖海珠 +2 位作者 高宿平 邹云峰 刘路路 《铁道学报》 EI CAS CSCD 北大核心 2024年第4期184-193,共10页
钢桁梁断面形式的不同可能会改变桥上列车的气动力,进而影响桥上列车运行安全性和舒适性。为此,以某千米级公铁两用悬索桥为工程为背景,通过风洞试验对三种常用钢桁梁断面形式的桥上列车进行测力、测压试验。研究结果表明,当单列车位于... 钢桁梁断面形式的不同可能会改变桥上列车的气动力,进而影响桥上列车运行安全性和舒适性。为此,以某千米级公铁两用悬索桥为工程为背景,通过风洞试验对三种常用钢桁梁断面形式的桥上列车进行测力、测压试验。研究结果表明,当单列车位于三种钢桁梁断面形式上的上游时,列车的阻力、升力系数无明显差异,而单列车位于下游时,列车的阻力、升力系数有较大的区别;在双车状态下,由于迎风侧列车的遮挡作用,改变了不同钢桁梁断面形式下列车的流场,使得钢桁梁断面形式对背风侧列车影响较小。无论列车位于上游、下游,其三种钢桁梁断面形式下列车的阻力系数、升力系数随风攻角的变化趋势一致。当列车位于上游时,其三种钢桁梁断面形式上列车顶部和底部圆弧过渡段都出现不同程度的流动分离,使得其列车平均风压系数不同;当列车位于下游时,三种钢桁梁断面形式上列车平均风压系数变化趋势一致,说明钢桁梁断面形式对下游列车的平均风压影响较小。列车位于上、下游时,其脉动风压系数会有显著的差异,其脉动风压系数的大小受腹杆布置形式的影响要比梁高的不同更为显著。本文研究结果可为大跨钢桁梁桥的断面形式选取提供参考和依据。 展开更多
关键词 钢桁梁断面形式 车桥组合 三分力系数 平均风压 脉动风压 风洞试验
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地震-波浪联合作用下考虑冲刷效应的跨海斜拉桥振动台试验研究
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作者 李忠献 郑庆涛 +1 位作者 苏俊省 赵博 《土木工程学报》 EI CSCD 北大核心 2024年第10期71-81,共11页
针对跨海桥梁服役期内可能遭受地震、波浪以及冲刷效应影响的问题,开展地震与波浪联合作用下考虑冲刷效应的跨海斜拉桥振动台试验,研究地震与波浪联合作用下冲刷效应对斜拉桥动力特性及关键截面动力响应(加速度、位移和应变)的影响规律... 针对跨海桥梁服役期内可能遭受地震、波浪以及冲刷效应影响的问题,开展地震与波浪联合作用下考虑冲刷效应的跨海斜拉桥振动台试验,研究地震与波浪联合作用下冲刷效应对斜拉桥动力特性及关键截面动力响应(加速度、位移和应变)的影响规律。研究表明:随着冲刷深度的增加,斜拉桥自振频率逐渐降低;冲刷深度的增加,降低了桥塔桩基础侧向约束,引起地震与波浪联合作用下桩顶动力响应明显增大,且增幅比其他位置更为显著;边墩墩顶加速度和相对位移均大于辅助墩墩顶,桥墩抗震设计时,应采用不同配筋率和不同的截面尺寸对边墩和辅助墩开展差异化设计;考虑冲刷效应明显增大了地震与波浪联合作用下塔底、边墩和辅助墩墩底等关键截面的应变,相较于无冲刷工况,大冲刷工况下塔底、边墩及辅助墩墩底应变分别增加39%、36%和42%,抗震设计时应高度重视。 展开更多
关键词 跨海斜拉桥 振动台试验 地震-波浪联合作用 冲刷效应 动力响应
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索-悬链线拱联合结构的受力机理与力学特征
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作者 郝天之 李春华 +2 位作者 杨涛 龙夏毅 邓年春 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第8期89-102,共14页
早期拱桥已运营多年,缺乏有效的养护,且设计荷载等级偏低;随着交通量的增加及车辆超载,其在活载作用下的力学性能已不能满足现代交通需求。为改善此类拱桥的受力性能,提出一种索-悬链线拱联合结构,在拱肋两侧对称设置索,使索和拱肋形成... 早期拱桥已运营多年,缺乏有效的养护,且设计荷载等级偏低;随着交通量的增加及车辆超载,其在活载作用下的力学性能已不能满足现代交通需求。为改善此类拱桥的受力性能,提出一种索-悬链线拱联合结构,在拱肋两侧对称设置索,使索和拱肋形成新的受力体系,从而改变悬链线拱结构的传力路径,进而降低拱结构的内力。在索-拱联合结构图式下,基于弹性中心法对其力法方程进行简化,采用近似曲线积分方法推导了竖向移动荷载作用下拱肋的内力解析解,并借助ANSYS有限元软件验证解析解的准确性;分析了在车道荷载作用下索约束位置、拱轴系数、矢跨比和轴向刚度比等设计参数对拱结构的影响,揭示了索-拱联合结构的受力机理和内力变化规律。研究表明,内力解析解与有限元结果的相对误差在1%以内;索的设置改变了拱结构弯矩影响线量值的正、负区间分布,而且有效地降低了拱结构弯矩影响线的峰值,从而使拱结构的整体弯矩得到较大幅度的降低,弯矩分布更均匀;沿拱脚至拱顶,拱结构弯矩的降低幅度和轴力的增长幅度均逐渐减小;轴向刚度比从0.02增加至0.10,拱脚负弯矩的减小幅度呈非线性增大,最大降幅达63.7%;索力的增长幅度与其数值大小成反比,当索设置在距拱顶0.3L(L为拱跨经)时,索力可增至轴向刚度比为0.02时的1.9倍。矢跨比对拱结构内力带来的影响不容忽视,矢跨比越大拱结构的内力变化幅度越大;拱轴系数对拱结构内力的影响可以忽略。 展开更多
关键词 索-拱联合作用 拱桥加固 悬链线拱 矢跨比 拱轴系数 内力影响线 解析解
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沁水盆地煤层气水平井缝网体积压裂工艺优化研究
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作者 王静 王青川 +2 位作者 张永琪 姚伟 张金笑 《中国煤层气》 CAS 2024年第1期8-11,47,共5页
从煤层气的解吸机理开展剖析,明确气井的增产是要构建立体的人工缝网,以增加更多的裂缝参与流动。为此首先分析实现人工缝网所需的压裂液体系,认为低粘度压裂液是形成大面积缝网的首要因素;其次,从施工排量、成本控制、安全风险等多方... 从煤层气的解吸机理开展剖析,明确气井的增产是要构建立体的人工缝网,以增加更多的裂缝参与流动。为此首先分析实现人工缝网所需的压裂液体系,认为低粘度压裂液是形成大面积缝网的首要因素;其次,从施工排量、成本控制、安全风险等多方面综合考虑,选取主体压裂工艺为桥射联作;再次就所选压裂工艺进行不断优化,根据现场实际情况设计出沁水盆地南部压裂所使用的施工参数。通过现场试验应用结果表明,该工艺能够满足构建体积缝网的需要,达到了增产的目的,为沁水盆地南部高阶煤煤层气井的压裂增产提供了新思路,为高效开发煤层气提供了新方法。 展开更多
关键词 煤层气 压裂 桥射联作 改造
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温度-轨道不平顺组合激励下车-轨-桥耦合动力响应分析 被引量:3
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作者 李鹏鑫 邢书科 +3 位作者 王兆刚 郭玉鹏 杨宇栓 杨荣山 《铁道标准设计》 北大核心 2024年第1期72-79,共8页
为研究温度-轨道不平顺组合激励下千米级矮塔斜拉桥上无砟轨道的行车安全,根据运营环境确定温度荷载工况,并采用ANSYS进行静力分析,确定最不利温度荷载工况。基于车-轨-桥耦合动力分析理论,分析温度-轨道不平顺组合激励下千米级的矮塔... 为研究温度-轨道不平顺组合激励下千米级矮塔斜拉桥上无砟轨道的行车安全,根据运营环境确定温度荷载工况,并采用ANSYS进行静力分析,确定最不利温度荷载工况。基于车-轨-桥耦合动力分析理论,分析温度-轨道不平顺组合激励下千米级的矮塔斜拉桥上无砟轨道行驶高速列车的动力响应,计算不同行车速度对车辆和桥梁动力响应的影响,并根据现有规范标准,评价千米级的矮塔斜拉桥上无砟轨道的行车安全,提出温度-轨道不平顺组合激励下桥上安全行车的舒适行驶速度范围。分析结果表明:以350km/h设计行车速度过桥时,动车、拖车垂向加速度最大值分别为0.8 m/s^(2)和0.66 m/s^(2),各动力响应数据均处于优良水平,满足相关规范要求;车体的加速度最值与行车速度呈正相关趋势;行车速度为400 km/h时,动车车体垂向加速度最大值为0.95 m/s^(2),是行车速度为250 km/h的1.48倍;当车速达到400 km/h时,Sperling舒适性指标由“优秀”转为“良好”,行车舒适度相对较差。为保证桥上行车安全,建议行车速度不超过400 km/h。 展开更多
关键词 高速铁路 斜拉桥 无砟轨道 组合不平顺 动力响应
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基于周期组合序列调制的三电平双有源桥均压策略 被引量:1
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作者 李林柘 邹旻洋 +2 位作者 吴京驰 费跃 舒泽亮 《电工技术学报》 EI CSCD 北大核心 2024年第2期514-524,540,共12页
应用在双极性直流微电网(BDC-MGs)的三电平双有源桥(TL-DAB)变换器,在匹配多类型不平衡负载运行时,输出侧正负母线电压的不平衡将影响系统稳定运行。该文首先分析不平衡负载工况时TL-DAB变换器输出侧上、下端口分电容电压的不均衡原因,... 应用在双极性直流微电网(BDC-MGs)的三电平双有源桥(TL-DAB)变换器,在匹配多类型不平衡负载运行时,输出侧正负母线电压的不平衡将影响系统稳定运行。该文首先分析不平衡负载工况时TL-DAB变换器输出侧上、下端口分电容电压的不均衡原因,并提出一种基于功率传输与电压均衡的周期组合序列调制策略。该均压策略无需附加额外电路和储能器件,仅通过改变功率传输的周期数及单周期内端口电平脉宽占比,便可实现输出侧上下端口传输功率的差额分配以达到分电容电压的均衡。仿真和实验结果表明,在上下分电容负载极不平衡工况下,相对于传统对称调制策略,该文所提均压策略可以将电压不均衡度从12%降低至1%以下。 展开更多
关键词 双极性直流微电网 母线电压 三电平双有源桥(TL-DAB)变换器 周期组合序列调制
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