Transverse Seismic Design and Analysis of an H Type Bridge Tower Cable Stayed Bridge

According to our current bridge seismic design codes, the bridge tower is explicitly required to remain almost elastic even under the excitation of occasionally happened earthquake. To achieve this seismic performance objective, usually the steel ratios of tower base and strut are required to satisfy the static loading demand and increase by a large margin as well in most engineering practices which leads to engineering inefficiency as well as a rising seismic demand for the substructure. Therefore, the structural design parameters including the location, the stiffness and the constrain condition of the strut with respect to the tower column of H shape tower were studied to explore their effect on the transverse seismic responses of cable-stayed bridge tower, Moreover, the effect of yield intensity of the strut on the seismic responses of the tower column is also studied. The results show that the location and the stiffness of the strut have a slight effect on the seismic responses while the transverse seismic demands of the bridge tower decrease drastically when the constrain condition between the cross beam and the tower column changes.     

Optimal placement of bidirectional sensor for extra high voltage transmission towers

Combined the optimal placement method of triaxial accelerometers based upon the effective independence algorithm(EFI3) and the improved one dimensional effective independence algorithm, the optimal placement method of bidirectional accelerometers for the tower (EFI2) is proposed. The modal matrix on x direction and y direction are used as input instead of the uniaxial data. And according to the most linear independence and greater energy distribution of modal shape, EFI2 can optimize the sensor placement of accelerometers on both directions at the same time. On a long span extra high voltage transmission tower as a case study, the sensor placement in the direction of transversal and longitudinal wires is optimized by the EFI2 method. And with assessment by two methods, it is found that the EFI2 method can optimize the sensor placement of accelerometers on both directions effectively.     

一起塔式起重机吊重坠落事故的分析

通过对一起塔式起重机吊重坠落事故的分析,找出了电控部分的设计缺陷,并提出了解决对策。     

Bending Performance of Tube Gusset Joint in Steel Tubular Tower for Extra High Voltage Transmission Line

This paper explored bending performance of tube gusset joint primarily according to experiment and finite element model. The method which is used to determine ultimate strength of the joint was proposed on the base of three joint types including /4 circle ribbed, half circle ribbed and circle ribbed stiffeners. Compared with the Japanese electricity transmitting steel tubular tower manufacture norm, a conclusion has been drawn that the ultimate strength has relationship with several different parameters. The result shows that the ultimate strength of the joint is related not only to the wall thickness t, diameter D, length of gusset plate B and the yield deflection δ at the top of the relevant section under the current status of the region, but also to the ribbed plate. The formula about ultimate strength has important application value for engineering design.     

Temperature Effect Analysis for structural state Estimation of PC Cable stayed Bridge

The temperature effect was of crucial importance to estimate structural state of existing PC cable stayed bridges. Taking Yonghe Bridge in Tianjin as a case, the influence of temperature effect, including temperature change of whole bridge, difference in temperature of cable and main girder, temperature Gradient in the transverse section of main girder, and temperature gradient in the transverse section of tower, was analyzed on geometry of bridge deck, inclined displacement at the top of tower and cable force. Based on observation data of Yonghe Bridge during the First and Second maintenance, effectiveness of temperature effect analysis based on the present bride code in China was verified. And then a modifying method of temperature effect in structural state estimation was proposed. It was shown that the temperature change of whole bridge and the difference in temperature of cable and main girder were the main factors to inclined displacement at the top of tower, and the difference in temperature of cable and main girder was the main factor to the deflection of main girder. Although a small error between measured and theoretical results caused by the rigidity deterioration of old bridge, the temperature effect analysis based on the present bride code in China could be feasible in structural state estimation of existing PC cable stayed bridges and provided reference for maintenance and construction control.     

COMPUTER-AIDED ANALYSIS AND DESIGN FOR THE BASE STRUCTURE OF A MOVABLE TOWER CRANE

This paper is one of the achievements of the researchitem for computer-aided design of tower crane's steel structure.In thepaper,taking the well-base structure as an example,first the method establishing the mechanical model is explained for the base structure ofa movable tower crane.Then the math model of its optimal design andthe N-S figures for the computer program is described and calculatedusing discrete optimal technology.Finally the problems related to thedesign for the base structure of a movable tower crane are briefly illu-strated.     

长距离高摩阻供水工程中的水锤计算与防护

针对广东省惠州大亚湾供水工程的特点，应用水锤理论进行长距离抽水系统的水锤计算及防护的研究，提出了相应的防护技术措施。计算结果表明，对于长距离输水系统，当以防负水锤为主时，采用不同形式的调压塔向管道补水是一种切实可行的办法，因而应充分考虑不同调压措施的混合运用，并对大容量调压塔的尺寸进行优化。