A kind of closure method of large-span continuous steel truss arch
The present invention relates to the closure construction method of large-span continuous steel truss arch in the bridge engineering.
The closure of traditional large-span steel braced arch for the amount of deflection of closure mouthful and the adjustment of yardarm corner, mainly utilizes Dun Ding to arrange vertical, direction across bridge, vertical bridge to hydraulic jack equipment, a closure mouthful construction need the steel braced arch be pushed up, fall (vertical position adjustment).In the long span bridge beam, the vertical top lifting amount and the horizontal adjustment displacement of purlin are very big, and the jacking force of jack is also very big, so the configuration difficulty and the operation easier of equipment such as jack are big, the system conversion process complexity, and construction risk is big.Bridge involved in the present invention is three Pin continuous steel truss arch structures, and as by tradition top, the beam method that falls closure, single Pin purlin lower fulcrum counter-force reaches 9000t, and every purlin need dispose 4 on the jack of 3000t level, and full-bridge needs 36 at least.Present domestic this tonnage jack that still do not have, what its research and development were produced involves great expense.
Abandoning tradition of the present invention with large-tonnage hydraulic jack top, the beam adjustment that falls closure mouth method, be the adjustment means with the suspension cable on the multilayer jump stay multilayer tower with suspended cable, in conjunction with the vertical shift of purlin section, the closure of realization steel braced arch, economical and practical.
Summary of the invention
The objective of the invention is at above-mentioned present situation, aim to provide a kind of a kind of closure method of economical and practical large-span continuous steel truss arch.
Feature of the present invention is to utilize close cable system of tower with suspended cable and the horizontal rope of multilayer to adjust yardarm displacement and corner, in conjunction with the vertical shift of purlin section, thereby closure mouthful rod member is installed smoothly, realizes the closure of steel braced arch.
Steel truss arch is established in the process, when Dun Ding both sides steel braced arch is symmetrical fully, the flat rope of multilayer is set to drawing system, realizes two cantilever erections of self-balancing type.Draw cable force to change the displacement and the corner of closure mouthful boom by adjustment, to translation, make be suitable for the joining the two sections of a bridge, etc unstressed installation of rod member of the gap of closure mouthful in conjunction with the vertical bridge of purlin section.
The main construction sequence of continuous steel truss arch span centre closure:
(1) behind the end bay closure of steel braced arch both sides, removes 3#, 5# pier pier-side bracket (4), 3#, the temporary fixed bearing of 5# pier are released to sliding support.2 gantry beams loop wheel machines (3) are installed on 4# pier vault girder steel, and the symmetric double cantilever is installed the steel braced arch.
(2) 3#, 5# pier steel purlin lock 3#, 5# pier girder steel sliding support afterwards to the about 170mm of 4# pier direction vertical shift.
(3) on the node that winds up of 3#, steel purlin, 5# Dun Dun top, tower with suspended cable (1) is installed.
(4) 3#, 5# pier girder erection crane continue to set up the steel purlin forward, hang three layers of hoist cable of stretch-draw (8), (9), (10) successively with the progress of setting up.Hoist cable one end is anchored on the tower with suspended cable, and the other end is anchored on the node of purlin.
(5) 4# pier two gantry beams loop wheel machines set up the steel purlin to bilateral symmetry, hang also three layers of flat rope of stretch-draw (11), (12), (13) successively with the progress of setting up.The two ends of flat rope all are anchored on the node of purlin.
(6) 3#, 4#, 5# pier steel girder erection are adjusted 3#, three layers of stay cable force of 5# pier tower with suspended cable to closure mouthful (7) position, adjust three layers of flat cable force of 4# pier simultaneously, to change main span steel braced arch closure mouthful both sides displacement; The vertical bridge of fine setting 3#, 5# Dun Ding is a mate-assist to displacement, successively realizes the closure of 4#-5# pier and 3#-4# pier two main span main trusses;
(7) remove 4# pier pier-side bracket; Progressively discharge 3#, 4#, the 5# pier draws cable force for three layers, makes main span tie-rod closure mouth be flared to design theory length, and a closure mouthful tie-rod is installed afterwards, finishes the closure of two main spans.
(8) progressively discharge removal suspension cable, flat cable force, and finally remove tower with suspended cable, remove girder erection crane, realize that continuous steel truss arch becomes the bridge state.
The closure method of this large-span continuous steel truss arch does not adopt traditional with large-tonnage hydraulic jack top, the beam adjustment that falls closure mouthful, with the suspension cable on the multilayer tower with suspended cable is the adjustment means, vertical shift in conjunction with the purlin section, realize the closure of steel braced arch, easy, the safety of this method has good economic effect.
Description of drawings
Fig. 1 continuous steel truss arch closure conceptual scheme
Fig. 2 a～Fig. 2 h continuous steel truss arch closing construction block diagram
The close cable system arrangement diagram of Fig. 3 tower with suspended cable
The horizontal rope self equilibrium systems of Fig. 4 arrangement diagram
Fig. 5 a, Fig. 5 b 3# pier, 5# Dun Dun top arrangement diagram
The corresponding relation of each several part title and numbering
|The each several part title
||The representative numbering
|Tower with suspended cable
| Horizontal rope
| Girder erection crane
|Hang beam and promote the station
|Girder steel promotes the station
|The closure mouth
|The first floor provinculum
|Second layer provinculum
|The 3rd layer of provinculum
|The flat rope of first floor
|The flat rope of the second layer
|The 3rd layer of flat rope
| Distribution beam 1
| Support buttress
| Bearing pad stone
| Pier cap
| Distribution beam 2
|Put on the bearing
The specific embodiment
(1) three layer of close cable system of tower with suspended cable is referring to Fig. 3.
The close cable system of tower with suspended cable is respectively applied for 3#, 5# pier steel truss arch is established; The anchor point of tower with suspended cable height, rope and angle of inclination selection all will guarantee the safety of steel braced arch in erection process, and satisfy and adjust the closure mouth when joining the two sections of a bridge, etc to suitable position.Pylon column lower end and steel braced arch wind up, and to reserve the free bearing plate hinged for node, begins assembly unit after the closure of end bay girder steel.
The tower with suspended cable suspension cable adopts high-strength parallel steel wire, outsourcing PE topping, and two ends anchor case anchoring up and down, the chill casting anchor is adopted in anchoring, and the hoist cable lower end is the stretch-draw end.The length of chill casting ground tackle is selected meticulously, to guarantee suspension cable enough adjusting length is arranged.
(2) horizontal rope self equilibrium systems is referring to Fig. 4.
The assembly unit of 4# pier steel braced arch, 2 internodes in pier top are installed on pier-side bracket, and all the other internodes are two cantilever symmetry cantilevers.Utilize the symmetrical configuration characteristics of 4# pier both sides steel braced arch, respectively at the level that is provided with between the corresponding node to drag-line.This horizontal Suo Jineng improves the stress of Steel Cantilever braced arch, has reserved the adjustment means for the closure of steel braced arch again.The high-strength parallel steel wire of horizontal Suo Caiyong, two ends are anchored in the girder steel node by the anchor case and reserve on the swallow plate.When main span was joined the two sections of a bridge, etc, 4# pier steel braced arch and pier-side bracket were fixed, adjusted first, second, third layer of horizontal cable force successively, made closure mouthful beam-ends amount of deflection and corner reach the ideal design state.
(3) Dun Ding arranges, referring to Fig. 5
3#, the formal bearing of 5# Dun Ding are freely movable bearing, place the design theory position, are initially lock-out state, carry out spacing with the thrust upper frame to pendulum on the bearing.After the end bay closure, remove the bearing constraint, end bay girder steel integral body in stride the vertical shift New Testament bundle branch seat of laying equal stress on, stride the side girder steel in the free cantilever erection until closure.In stride steel braced arch closure before, to finely tuning, the girder steel vertical shift is to finish in the slip of laying out down by pendulum (21) on the bearing to 3#, the vertical bridge of 5# pier girder steel.The formal bearing of 4# Dun Ding (14) is a fixed bearing, places the design theory position, need not conversion.In the girder steel work progress, only arrange vertical bridge to thrustor at 3#, 5# Dun Ding, 4# Dun Ding does not establish top lifting equipment.