Liu A.-L.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2013
The main bridge of Anqing Changjiang River Railway Bridge is a steel truss girder cable-stayed bridge with double pylons, triple cable planes and with span arrangement(101.5+188.5+580+217.5+159.5+116) m. The pylon piers No.3 and No.4 of the bridge are all supported on the foundations that are respectively made up of 37 nos.of the φ3.4 (3.0) m variable diameter frictional bored piles with the length of the piles being up to 108 m and 110 m. The foundations for the pylon piers were constructed by the double-wall steel cofferdam scheme. By way of the artificial effort, the construction environment of the stable stratum was created, the bored holes of the clear water method were completed, using the KTY4000 boring machine. After the holes were bored to the designed elevation, the holes were cleared off for the first time by the boring machine and the holes were then quantitatively inspected, using the JJC-1D Bored Hole Ultrasonic Inspection Instrument. Further after the holes were proved to be qualified through the inspection, the boring machine was removed away, the reinforcement cages and tremie ducts were lowered into the holes and the holes were cleared off for the second time through the ducts. Finally the tremie concrete for the piles was cast to complete the construction of the pile foundations. In the construction of the piles, no accidents like the falling of the boring bits and breaking of the piles took place and the piles were all qualified as Class I piles according to the inspection.
Deng Y.-F.,China Railway Major Bridge Engineering Group Co. |
Zhou M.-X.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2013
The main bridge of Huanggang Changjiang River Rail-cum-Road Bridge is a double-deck steel truss girder cable-stayed bridge with double pylons and double cable planes. The steel truss girder of the bridge was erected by the piece-by-piece assembling method and the girder sections between the pylons and auxiliary piers were erected by the balanced two-side cantilever method. For the erection of the steel truss girder, a kind of the self-balanced wind-resistant device was invented and was used to reinforce the structural safety of the girder in the process of the cantilever erection. The deck cranes were used to directly erect the girder sections in the areas of the pylons and the special spatial positioning riggings were used to lift and install the multi-angle and spatially inclined web members. The integrally movable construction scaffolding was developed and the intrinsic safety of the erection process of the girder was hence improved. On the basis of the sensitivity analysis, the different closure adjustment measures were researched and the highly accurate and rapid closure of the central span steel truss girder was achieved. Practice proves the whole erection process of the girder of the bridge is safe and favorable, the geometric shapes of the completed bridge are smooth and the various indices of the bridge can completely satisfy the design requirements.
Luo R.-H.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2014
The main bridge of Yingwuzhou Changjiang River Bridge in Wuhan is a three-tower suspension bridge with span arrangement (200+2×850+200) m. The foundation for the north anchorage of the bridge is the gravity caisson foundation of "holed ring+crisscross partition walls". The external diameter of the caisson is 66 m and the height is 43 m. The foundation for the Tower No.1 is comprised of 44 nos. of φ2.0 m bored piles, for the Tower No.2 is of 39 nos. of φ2.8 m bored piles and for the Tower No.3 is of 20 nos. of φ2.8 m bored piles. The foundation for the south anchorage is the kind of the foundation of "circular rock-socketed diaphragm wall+lining". The diaphragm wall is the reinforced concrete structure, the external diameter of the wall is 68 m and the thickness is 1.5 m. In the light of the characteristics of the foundation works of the bridge, the caisson for the north anchorage was constructed by the caisson height extending and caisson sinking in 3 times. The pile foundation for the Tower No.1 was constructed by the scheme of artificial island and by the double-row protection bored piles. The foundation for the Tower No.2 was constructed by the scheme of constructing the steel cofferdam first and the working platform late, in which the cofferdam was launched to the river by the air bag method in integrity. The foundation for the Tower No.3 was constructed by the scheme of constructing the working platform first and the cofferdam late and by the single-row protection bored piles and the diaphragm wall for the south anchorage was constructed by the scheme of hydraulic trench cutter aided by percussion boring. ©, 2014, Bridge Construction. All right reserved.
Liu Y.-H.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2015
The non-navigable span bridge of Contract CB05 of the Hong Kong-Zhuhai-Macao Bridge is a 85-m span steel and concrete continuous composite girder bridge. The foundations for the piers of the bridge are the ones of steel pipe composite piles. At each pier, 6 composite piles are provided and there are totally 372 piles for the whole bridge. In the light of the structural features and construction difficulties of the bridge, the construction schemes of a common boring platform of the "steel pipe piles+sectional steels" structure (Scheme 1) and an integral boring platform of the "integral steel truss type" structure (Scheme 2) were proposed for construction of the foundations. Through comparison of those aspects of the civilization construction, safety, environment protection, construction efficiency and construction cost, it was determined that the Scheme 2 should be selected. For the Scheme 2, the components of the boring platform were all fabricated in workshop following the standardization requirements and were welded into the integral steel truss structure. The steel truss structure was then transported by ship to the pier site where the structure would be installed or integrally removed for repeated usage at other pier sites by floating crane and at this stage, the construction of the boring platform was completed. The selected Scheme 2 can effectively shorten the time interval of shifting the platform from pier site to pier site and has advantages of high efficiency, safety, environment protection, energy saving and fast speed. ©, 2015, Wuhan Bridge Research Institute. All right reserved.
Yu B.-J.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2013
The main bridge of Tongling Changjiang River Bridge on Hefei-Fuzhou Railway is a multi-span continuous steel truss girder cable-stayed bridge with double pylons and triple cable planes. The pylon pier No.3 of the bridge is supported on the round-ended caisson foundation that is 68 m high, of the which the upper 18 m part is the reinforced concrete structure and the lower 50 m part is the steel shell concrete structure that totally weighs about 5000 t. The 50 m steel caisson was manufactured and assembled in 6 lifts in workshop, loaded onto the barge by the 1200 t floating crane and transported to the pier site by the 12800 t barge. At the pier site, the first lift of the caisson was integrally lifted to the river by the floating crane, floated there and was temporally positioned by the anchors. The second to the sixth lifts were integrally lifted in succession by the floating carne and jointed with the previous lift(s) of the caisson. The caisson was accurately positioned by the heavy anchors without utilizing the guiding barge. Practice proves that the construction techniques for manufacturing, transporting and site jointing of the full lifts of the huge steel caisson can ensure the overall quality of the caisson and can also accelerate the construction progress of the caisson.
Wang D.-H.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2016
The non-navigable span approach bridge of the Pingtan Straits Rail-cum-Road Bridge over the shallow water area (the water depth being less than 15 m) is a 48-m span prestressed concrete girder bridge. The foundations for the bridge are the bored piles that were constructed, using the cofferdams. A cofferdam for the construction of the piles is the steel boxed cofferdam structure that has the plan dimensions of 14.8×23 m and the height of 12.3 m and in the cofferdam, two tiers of the internal supports were arranged. Through the calculation of the load cases of anti-buoying of the cofferdam by pumping out the water and anti-sinking of the cofferdam after casting the concrete for the pile cap under the condition of base sealing of the cofferdam, it was determined that the depth of the base sealing concrete for the cofferdam should be 2 m. With reference to the sea condition characteristic of the Pingtan Straits and in thorough consideration of the wave force action and the great tidal difference influence, the cofferdam was integrally assembled and was integrally lowered to its designed elevation, using the jacks after the bored piles were constructed. In the cofferdam, 3 tiers of the guiding and limiting devices were also arranged in order to ensure the safety of the cofferdam at the time the cofferdam was being lowered into the water. After the base for the cofferdam was sealed and the water in the cofferdam was pumped out, the slinging system of the cofferdam was installed for the second time, the hangers and slinging corbels were installed again in order to accommodate the construction of the pile cap. The side plates and bottom plate of the cofferdam were connected by pins and the diagonal struts were welded to fix the side plates and bottom plate in order to resist the vibration caused by the wave forces. © 2016, Journal Press, China Railway Bridge Science. All right reserved.
Tao J.-S.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2016
The main bridge of the Qingshan Changjiang River Highway Bridge in Wuhan is a cable-stayed bridge with double pylons, double cable planes and with span arrangement (350+938+350) m. The foundation for the pylon pier No. 20 of the bridge is comprised of 60 nos. of φ2.5 m bored piles and was constructed, using the semi-floating dumbbell-shape double-wall steel cofferdam. The length of the cofferdam is 103.8 m, the diameter of the part of a cylinder is 43.4 m, the total height of the cofferdam is 37 m and the wall thickness is 2 m. Vertically, the cofferdam is divided into 3 parts of the bottom lift, middle lift and top lift, of which the height of the bottom lift is 18.2 m. The bottom lift of the cofferdam was manufactured in the shipyard and was assembled and welded into an integrity on the horizontal building berth also there. By the aid of 44 sets of the rail trolleys, the lift of the cofferdam was shifted from its assembling place to the support changing area of the wedge type launching cradles and was synchronously jacked up apart from its existing steel stands by the jacks on the rail trolleys to start the horizontal transverse shifting. After the supports of the lift of the cofferdam were changed at the comb type building berth, the lift of the cofferdam was then carried by 13 sets of the wedge type launching cradles, was synchronously slid down along the slope slipway and was finally steadily launched to the river and floated there. © 2016, Journal Press, China Railway Bridge Science. All right reserved.
Li L.-S.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2016
The main bridge of the Qingshan Changjiang River Highway Bridge in Wuhan is a cable-stayed bridge with double pylons, double cable planes and with span arrangement (350+938+350) m. The foundation for the main pier No. 19 of the bridge is the one that is comprised of 60 nos. of the variable diameter bored piles (the diameters of the upper 25 m of the piles being 3.0 m while those of the lower 67 m being 2.5 m) and the length of the piles is 92 m. In comprehensive consideration of the various factors of the topography, hydrology, geology and construction time schedule in connection with the construction of the piles, it was determined that the piles should be constructed, using the scheme of the “hydraulic reclamation island platform+rotary boring machine”. The reclamation island platform (the plan dimensions of the platform being 118 m×71 m) was used as the boring construction platform and the construction over the river was thus transformed to that on the land. After the reclamation island platform was well constructed, the steel casings for the piles were inserted and driven, using the resonance-free electrical vibration hammer aided by the 500 t caterpillar crane. The holes of the piles were bored by the large rotary boring machine, the high-quality slurry and circulating system were provided in the boring and the bored holes were cleared by the air-lifting reverse circulation. When the holes were cleared off, the reinforcement cages (a cage being 93.7 m long and being fabricated on the jig by the method of the long line match and a few joints) were lowered into the holes, the C40 tremie concrete was cast through the tremie ducts and at this stage, the construction of the bored piles was completed. The ultrasonic inspection of the completed piles of the main pier No. 19 proved that the shafts of the piles were all up to the Class I piles. © 2016, Journal Press, China Railway Bridge Science. All right reserved.
Yao S.,China Railway Major Bridge Engineering Group Co.
Journal of Railway Engineering Society | Year: 2013
Research purposes: With rapid construction of the intercity railways, the more and more upper stiffened continuous steel truss bridge structure like suspension bridge will be used. The structure of such kind of bridge is fresh, but its main beam has not enough strength when the utmost cantilever is assembled. So it is difficult to assemble it with the conventional methods. The bridge construction is often affected by the navigation, tide change and low construction budget. Consequently, it is necessary to research a economical, safe and quick method for the foundation construction and steel-beam assemble to ensure the construction procedure and save the construction cost. Research conclusions: Many rapid construction technologies were used for the foundation construction and erection of the superstructure. The applicable results show: (1) Application of the standardized construction for the trestle bridge and application of the rapid and safe member can make the turnover rate of the member more rapid and the manufacture and erection costs lower. (2) Application of suspension box-cofferdam which is sub-sealed with funnel instead of concrete for the cushion cap of the main pier, can effectively reduce the concrete quantity for sealing the bottom, lighten the design weight of cofferdam and shorten the construction period of cushion cap and cut the cost by 50%. (3) For construction of the superstructure, application of the one-end-cantilever-assemble way along with the temporary stay cables fixed between stiffening beams of medium span can overcame the problem of strength deficiency of the main beams when the utmost cantilever is assembled, much reduce the crane amount, have no assisting cable tower and temporary piers within the span and cut the cost by 80%. (4) For construction of the main beam, application of the erection method that the beam is not jacked up on the main piles while the beam is jacked up or laid down on the side piers can reduce the large jack quantity and ensure the construction safety, getting the notable economical effect. (5) This rapid construction method for the bridge can provide the reference to construction of cushion cap and erection of the upper stiffened continuous steel truss bridge affected by tide.
Zhang C.-X.,China Railway Major Bridge Engineering Group Co.
Bridge Construction | Year: 2015
The main bridge of the Xijiang River Bridge on the newly-built Nanning-Guangzhou Railway is a half-through steel box basket handle arch bridge with span arrangement (41.2+486+49.1) m and the arch ribs of the bridge are the steel box structures of variable depth. In the construction of the bridge, the segments G0~G3 of a arch rib were erected by the 500-t capacity floating carne and the segments G4~G21 were cantileveredly assembled and erected by the "cable crane+fastening stay method". To ensure that the segments of the arch rib could be smoothly lifted, erected and accurately set in place, the scheme of constructing the towers for support of both the cable crane and fastening stays was adopted. The lifting ears for the segments G4~G9 were arranged on the upper flange plates and upper cross section of the arch rib and for the segments G10~G21 were arranged on the upper flange plates. At the time the arch rib was well assembled, the segments were temporarily connected by the connecting pieces and limiting corbels. The fastening point system for a fastening stay was the two-way hinge and was comprised of the fastening ear, anchor box and pin. The anchor points of the anchor cables were arranged in the anchorage on both sides and the jacking ends of the fastening stays and anchor cables were all arranged on the towers. To ensure that the geometric shapes and force conditions of the completed bridge could be accordant with those in the design, the segments of the arch rib were manufactured by the workmanship of the "6+1" semi-long line match method and the pre-embedded segments of the arch rib were positioned by the accurate spatial positioning technique. The geometric shapes of the arch rib were accurately adjusted for one time after every 3 segments were assembled. In the process of closure of the arch rib, the fastening stay forces were adjusted, the closure temperatures were comtrolled and after the closure of the bridge, the errors of the length, width, height and diagonal lines of the main arch were all controlled within ± 2 mm and could meet the design requirements. ©, 2015, Wuhan Bridge Research Institute. All right reserved.