Kang J.-T.,Wuhan University of Technology |
Yuan M.,Wuhan University of Technology |
Wang T.-M.,The 1st Engineering Co.
Bridge Construction | Year: 2013
To study the influences of the structural parameters of long span self-anchored suspension bridge on the dynamic performance of the completion state of the bridge, the main bridge of Taohuayu Huanghe River Bridge was cited as an example and a spatial finite element model for the whole bridge of the example bridge was established on the platform of the software MIDAS Civil 2012. The subspace iteration method was used to carry out the dynamic calculation and the influences of the parametric changes of the sag-to-span ratios, dead load intensity and structural stiffness on the dynamic performance of the completion state of the bridge were analyzed. The results of the calculation and analysis demonstrate that the bridge has the rational vibration modes and dense frequency spectrum distribution. The influence of the sag-to-span ratios on the vertical bending vibration mode and frequency of the structure is great. The influence of the dead load intensity on the vibration modes and frequencies of the different orders of the structure is significant. The main cable tensile stiffness mainly has influence on the vertical bending and torsional vibration modes and frequencies of the stiffening girder. The influence of the hanger tensile stiffness on the vibration modes and frequencies of the different orders of the structure is very little. The influence of the bending stiffness of the stiffening girder on the vertical, lateral and torsional vibration modes and frequencies is significant. The tower longitudinal bending stiffness mainly has influence on the longitudinal fluctuation vibration mode of the structure.
Mei X.-D.,Bridge Science Research Institute Ltd. |
Mei X.-D.,Key Laboratory of Bridge Structure Safety and Health of Hubei Province |
Li Y.-M.,The 1st Engineering Co. |
Li Z.,The 1st Engineering Co.
Bridge Construction | Year: 2013
To provide solution to the problem of influence from tensioning of the prestressing strands for simply-supported girder and to the optimization of removal of the temporary suspenders and pre-raising amount of the inclination angle of the first segment in the process of span-by-span assembling and erection of precast segments of the prestressed concrete girder bridge, the north approach bridge of Taohuayu Huanghe River Bridge in Zhengzhou on the inner side of the river dyke was cited as an example. The forces of the suspending system formed by the overhead launching gantry, temporary suspenders and concrete main girder for assembling and erection of the precast segments of the bridge were analyzed, using the simplified finite element model that could fulfill rapid calculation and could produce reliable calculation results. The results of the analysis indicate that the tensioning of the prestressing strands for simply-supported girder can cause the main girder to camber inversely and make the force distribution of the temporary suspenders become dramatically worsen, the forces of the midspan suspenders reduced and the forces of the suspenders nearby the girder ends increased. The optimal sequence of removal of the temporary suspenders for system transformation is that the removal should proceed symmetrically from the midspan towards the ends of the girder. Most of the suspenders can be removed in one time while the rest of the suspenders need to relaxed first before removal. The pre-raising amount of the inclination angle of the first segment of the bridge to be constructed by the suspending and assembling technology is 13.6 mm/3.84 m.
Wang M.-H.,Chongqing Guizhou Railway Co. |
Zhang Z.-A.,The 1st Engineering Co. |
Zhang Q.,Chongqing Guizhou Railway Co.
Journal of Railway Engineering Society | Year: 2015
Research purposes: Tianping tunnel of Chongqing-Guizhou railway is 13.928 km long, and is the key workpoint. The geostress conditions of Tianping tunnel is very complicated. When entering the construction of inclined shaft, the deformation of initial supports and baseboard was serious, by measuring the crustal stress, the inclined shaft was judged extreme-high geostress zone, which was apt to effect large deformation. So the problem was what reliable construction methods was adopted to safely pass the high geostress zone. Research conclusions: By the construction practice of Tianping tunnel, the paper summarized the following construction methods to guarantee the safety and quality of high geostress zone: (1) Increase the deformation allowance to guarantee that the deformation of soft rock under high stress was not not beyond limit. (2) Strengthen monitoring measurement and predict the deformation of the surrounding rock to guide the construction. (3) Timely adjust support parameter and dynamically adapt the surrounding rock. (4) Timely cast the secondary linings, when deformation rate was continuously less than 1 mm/d for seven days. (5) The research conclusion can provide references and lessons for constructions of similar high geostress tunnels. © 2015, Editorial Department of Journal of Railway Engineering Society. All right reserved.
Zhou G.-J.,The 1st Engineering Co.
Bridge Construction | Year: 2015
The main bridge of the New Baishatuo Changjiang River Bridge is a steel truss girder cable-stayed bridge with span arrangement (81+162+432+162+81) m. The foundation for the main pier No.3 of the bridge is the one that is comprised of 36 nos.of ■3.2 m bored piles and the dimensions of the pile cap is 67.4 m×31.3 m×6 m. In comprehensive consideration of various factors in the construction, it was determined that the foundation should be constructed by the scheme of the “underwater controlled blasting+multi-function platform+double-wall steel boxed cofferdam”. The underwater blasting was carried out in parallel with the assembling of the multi-function platform. The construction of the bored piles and the assembling of the double-wall steel boxed cofferdam were carried out also in parallel in separated double levels. In the underwater blasting, the emulsion explosive was used. The multi-function platform was integrally floated to the pier site, was lifted in place, using the technique of multi-point and synchronous lifting and together with the flood controlled piles at the pier site, the boring platform was formed. The steel casings for the bored piles were inserted and driven by the vibration pile driver. The holes of the bored piles were constructed by the method of clear water ail lifting and reverse circulating. After the cofferdam was well assembled, the cofferdam was filled in with water and was ready to sink down, the leakage in the cofferdam was stopped, the cofferdam was rip-rapped and backfilled and the base sealing of the cofferdam was constructed. The platform was then lowered down and transformed into the internal support and finally the water in the cofferdam was pumped out and the construction of the pile cap was carried out. ©, 2015, Wuhan Bridge Research Institute. All right reserved.
Lu Z.-L.,The 1st Engineering Co.
Bridge Construction | Year: 2013
The main bridge of Jinshan Huanghe River Bridge is a hybrid structure of 15 units of (2×108)-m single concrete T-frames and stiffening steel truss girders. The construction of the steel truss girders of the bridge was carried out in two stages of embedding the lower gusset plates of the girders in the concrete T-frames and installing the members of the girders, of which the embedding of the gusset plates was the prerequisite for the smooth installing of a full span of a girder. In this paper, the construction techniques for embedding the gusset plates were summarized. In the construction, the locations of the gusset plates were firstly determined through the accurate setting-out. Outside around the embedding area of the gusset plates, the cantilever platform was set up, the gusset plates were then placed in the cantilever device, preliminarily adjusted and set in place and finally by way of welding the sectional steel and bolts, the gusset plates were accurately adjusted and positioned according to their three-dimensional coordinate of the longitudinal, transverse and vertical directions until the plates could meet the construction requirements.
Ren S.-Z.,The 1st Engineering Co.
Journal of Railway Engineering Society | Year: 2013
Research purposes: Based on the research on the comprehensive budget management of the Yangtse River project in Wuhan, this paper analyzes the work steps and key points of the management of the comprehensive project budget for the purposes of strengthening the project management in whole process, enhancing the the management level and achieving the business targets. Research conclusions: (1)The management of the comprehensive project budget, as an internal management and control means, has been widely used in the areas of the industrial and commercial enterprises. But it has not been used comprehensively and deeply in the construction industry because of the industrial limitations. (2)The management of the comprehensive project budge is the whole process and all levels' budget management of allocating the various resources that needs all persons to take part in the management. In the construction industry, the management of the comprehensive project budget can be regarded as the forecast means in the integrated system of the construction progress, construction security, construction cost and construction fund. (3)The comprehensive management was used in the Yangtse River project in Wuhan. The business targets was achieved before the project completed and the project management level was improved much to make the project management being in line with the international standard. (4)The management of the comprehensive project budget can be used in the construction industry.