Summary of the invention
The object of the present invention is to provide a kind of simple to operate, safe arch bridge jack-up construction method.
Technical scheme particular content of the present invention is: a kind of construction method of arch bridge jacking, comprises the following steps:
(1) build jacking base: arch bridge base position is excavated to concrete foundation end face, then concreting carries out Longitudinal Extension processing to former impost to bridge inner side, new impost length after expansion is greater than the distance of the first arch rib outside to the second arch rib inner side, expansion position and former basis, between former impost, answer dabbing, the concavo-convex degree of depth is not less than 6mm, can make like this those widened sections position and former basis, the connection of former impost is more firm, bar planting between inclined-plane, new impost after extension process is as jacking base, jacking base is the counter-force basis of arch bridge jacking, build and connect into entirety with upper tray beam at the mixed soil of doubting of arch bridge jacking rear use in place.
(2) build pallet beam and stretch-draw prestressing force steel strand: above impost, build pallet beam, pallet beam is rectangular-shaped concrete platform, its outer end end points is in the first arch rib outside, and its inner end points is in the inner side of the main arch of same level news, and its width is greater than the width of arch rib; Clearance height between pallet beam and jacking base equals suspended ceiling steel plate thickness, jack height, tool-type pad thickness and reserved operating space height sum; In pallet beam, stretch-draw anchor has some prestress wires, and main arch two ends are socketed and process to offset the horizontal thrust in arch bridge jacking process, and the size of prestress wire and quantity will be analyzed, calculate and determine arch bridge is stressed.Described pallet beam can pre-buried some longitudinal corrugated pipes in the time building, for prestress wire described in stretch-draw anchor.
(3) stopping means is set: build steel concrete block in abutment termination, vertical misalignment occurs while preventing arch bridge jacking; On bridge floor guardrail, rivet triangular steel support, steel cable one end is fixed on triangular steel support, and the other end penetrates turnbuckle upper end, and turnbuckle lower end connects anchor pole, and anchor pole anchors in arch bridge base, adjusts the restriction of turnbuckle shell, adjusts arch bridge lateral displacement.Before each jacking, first the reserved needed length of jacking stroke at flange socket place, tightens turnbuckle, carries out jacking.In the time there is unstability in jacking process, should adjust in time turnbuckle and make bridge keep stable.
Wherein, the order of step (1), (2), (3) is interchangeable.
(4) integral jacking:
A. clear up behind shrinkage joint, arrange, install several jack and supporting steel pipe on jacking base, arrange, several jack are installed at abutment bearing place, the weight of the number Main Basis jacking bridge of required jack and supporting steel pipe is determined.
B. after all preparation completes, jack is carried out to punching press 60%, make it tentatively stressed, then utilize rope saw to being connected between anchor point and bridge arch and abut carrying out cutting and separating, it is all thrown off, cutting absolute altitude position between lifting platform and jacking base.
C. check the reliability of jack-up system, comprise the reliability of check element, the reliability of system, the cleannes of hydraulic oil, stability, the stability of position closed loop etc. of power closed loop.
D. weigh: first will carry out pressurize test, install oil cylinder, oil pipe, pumping plant console, monitor and check errorlessly, by 70%~90% pressurization of calculating load, carry out the pressurize test of oil cylinder, check the working condition of whole system, oil circuit situation, before jacking, should measure the actual loading at each Jacking point place according to calculating jacking load, adopt the mode loading step by step to carry out, in certain top lifting height (1 ~ 10mm), by repeatedly adjusting the oil pressure of each group, can set one group of jacking oil pressure value, make jacking pressure and its upper load on each summit in a basic balance, by the measured value of every and calculated value comparison, calculate its measures of dispersion, jointly analyze reason by hydraulic engineer and structural engineer, finally organize a reference value while determining that can this measured value serve as jacking by leader, as differ greatly, to be adjusted accordingly.
E. determine and deliver for a check a little.
F. try jacking: in order to observe and examine the duty of whole jack-up construction system and the check to weighing results, before formal jacking, should try jacking, after examination jacking finishes, provide the situations such as overall attitude, displacement structure, for formal jacking provides foundation;
D. formal jacking.
(5) connect high construction, bridge jacking carries out abutment and props up that seated connection is high builds after completing, and new impost connects height and builds;
(6) bearing is installed: the high part of concrete joint has been constructed, and concrete curing reaches after design strength, erection support, and beam falls;
Further, the embedment length of described anchor pole is the bolt diameter of 20 times.
The invention has the advantages that simple to operately, safe, power transmission is clear and definite; Though jacking rear arch is across slightly reducing, jacking rear abutment base integral in place is good, and overall safety degree is higher than former design.
The specific embodiment
Below in conjunction with specific embodiment and Figure of description, the present invention is further described.
What the arch bridge for the treatment of jacking was certain speedway is upper across pedestrian overcrossing, and its structure is Deck Arch Bridges.49.59 meters of overall length of bridge, main span is 36.6 meters, and bridge is wide 5.5 meters, and class of loading is highway-II level.Superstructure has been adopted C40 steel bar concrete, support cast-in-place, and mortar flag stone chute is established in abutment both sides.Now, due to headroom deficiency, need carry out jacking to its entirety, top lifting height is 1.4 meters.
As shown in Figure 1, before arch bridge jacking, first to carry out Construction Scheme and demonstration and carry out some preparations of construction.
One, Construction Scheme and demonstration
(1) prestress steel twist line computation
This engineering adopts civil midas to set up bridge analysis model.Modeling after the first bridge opening is established pallet beam, conditions setting operating analysis obtains each Bearing Seat Force as shown in Figure 3.Horizontal force size
Therefore intend in this work progress adopting 16 steel strand, every 4 is a branch of.
When construction, actual stretching force should amplify according to loss of prestress calculated value.
Be below loss of prestress calculated value:
Loss due to anchorage deformation:
Ground tackle adopts porous intermediate plate anchor, adopts the strand tapered anchorage reinforcing bar value of inside contracting and tension ground tackle distortion to get, and stretching end is to the distance 1=19917mm between ground tackle end
The modulus of elasticity of prestressed reinforcement
The stress relaxation loss of prestressed reinforcement:
Meet the demands.
Two, pallet beam arrangement of reinforcement calculates
1. resistance to compression is calculated
Therefore resistance to compression meets the demands.
Only need to press constructional reinforcement.
Three, anchored end partial pressing is calculated
1. local compression area checking computations
The single hole anchor diameter 100mm adopting, the thick 16mm of backing plate, after 45 ° of diffusions, the diameter of compression area is increased to 100+2 × 16=132mm.
(meeting the demands)
2. local compression checking of bearing capacity
Under anchor plate, configure three grades of spiral reinforcing bars, bar diameter 10mm, 4 circles (enclosing apart from 25mm loop diameter 150mm).
Meet the demands.
Two, preparation of construction
Comprise the preparation of construction work that fence setting, place layout etc. are conventional, these have not just described in detail.Soil excavation requires arch bridge base position to be excavated to concrete foundation end face 5.
Three, build jacking base 3, pallet beam 7
(1) build jacking base: arch bridge base position is excavated to concrete foundation end face, then concreting carries out Longitudinal Extension processing to former impost 31 to bridge inner side, new impost length after expansion is greater than the distance of the first arch rib 21 outsides to the second arch rib 22 inner sides, between expansion position 32 and former basis, former impost 31, answer dabbing, the concavo-convex degree of depth is not less than 6mm, can make like this those widened sections position more firm with being connected of former basis, former impost 31, bar planting between inclined-plane, the new impost after extension process is as jacking base.
(2) build pallet beam and stretch-draw prestressing force steel strand 6: above impost, build pallet beam, pallet beam is rectangular-shaped concrete platform, length is respectively 5680mm, 3500mm, 600mm, its outer end end points is in the first arch rib 21 outsides, its inner end points is in the inner side of the main arch 1 of same level, and its width is greater than the width of arch rib; Clearance height between pallet beam and jacking base equals suspended ceiling steel plate thickness, jack 8 height, tool-type pad thickness and reserved operating space height sum; Gap between pallet beam and jacking base is used for laying jack 8, its highly about 600mm, pallet beam has been embedded with 4 longitudinal corrugated pipes 71 while building, facilitate stretch-draw anchor to have prestress wire 6, and main arch 1 two ends are socketed and process to offset the horizontal thrust in arch bridge jacking process.In the present embodiment, use 16 of 7 strands of prestress wires, every 4 is a branch of.
Four, stopping means is set
Longitudinal limiting device is set: build steel concrete block in abutment 4 terminations, vertical misalignment occurs while preventing arch bridge jacking.
Horizontal limit devices is set: on bridge floor guardrail 12, rivet triangular steel support 14, steel cable 131 one end are fixed on triangular steel support, the other end penetrates turnbuckle 132 upper ends, turnbuckle 132 lower ends connect anchor pole 133, anchor pole 133 anchors in arch bridge base, and the embedment length of anchor pole 133 is the bolt diameter of 20 times.Adjust the restriction of turnbuckle shell, adjust arch bridge lateral displacement.Before each jacking, first, in the reserved needed length of jacking stroke of flange connections 13, tighten turnbuckle 132, carry out jacking.In the time there is unstability in jacking process, should adjust in time turnbuckle 132 and make bridge keep stable.
Five, integral jacking
1. cleaning shrinkage joint
Carefully check in shrinkage joint, jacking section two ends, whether have the foreign material, the especially concrete that hinder jacking before jacking, in order to avoid beam body is damaged when jacking.
If there is concrete in shrinkage joint, to chisel shrinkage joint with air compressor machine and extract rubber strip out, inspection box beam block contacts situation with casing, also cuts in the lump if desired, confirms that bridge is separated into absolute construction.
2. jack 8 and supporting steel pipe 9 are installed
(1) jack is arranged and supervising device
1) jack is arranged
A, anchor point place jack are arranged: as calculated, jacking bridge weight is about 500 tons, and every side is arranged 6 row's Jacking points altogether.First arrange 2 200 tons of hydraulic jack, 4 100t jack at every side anchor point place, the top power of 1600 tons can be provided altogether, its safety stock coefficient is 3.2, can meet top power demand;
B, abutment bearing 41 place's jack are arranged: through primary Calculation, the support reaction of abutment bearing 41 positions, both sides is about 10 tons, on present every side abutment bearing 41, arranges 2 100 tons of hydraulic jack, can meet top power demand;
Full-bridge is arranged 4 of 200 tons of hydraulic jack altogether, and 8 of 100 tons of hydraulic jack, can provide 1600 tons of top power altogether.
2) jack is installed
Jack is inverted, and bottom is connected on concrete bracket, installs before jack, checks smooth the bottom surface in the scope of installation jack.The axis that should guarantee jack when installation is vertical, produces horizontal component in order to avoid install to be tilted in jacking process because of jack.At the bottom of jack furred ceiling steel plate and beam, pad with wedge-shaped steel plate, at the bottom of beam, use high grade mortar levelling.
3) jack grouping
Every side anchor point is a control point, and full-bridge is established totally 4 control points altogether; A displacement monitoring sensor is all established in each control point.
4) jacking stroke monitoring: adopt the displacement transducer that precision is 0.01mm to monitor.
3. steel is installed to be supported
Steel brace foundation use former pier or widen after pier, and between former pier shaft, stay 15cm space.When steel support is installed, to strictly control its verticality and be no more than 2%, prevent from occurring the situation of unstability in the time of jacking.
The special temporary steel cushion block of jacking be used in respectively under jack and temporary supporting under.Temporary steel cushion block is corresponding with the steel pipe of jacking bracket system, also adopts Φ 500 × 12mm steel pipe, and two ends welding is thick is the flange of 12mm.Steel cushion block has I, II, III, IV Four types, and for adapting to the jacking stroke of jack, the height of steel cushion block is respectively 100mm, 200mm.Each temporary supporting top all configures the steel plate that a pair of voussoir and thin and thick differ, to meet the requirement of different top rise.For avoiding supporting unstability in jacking process, between steel cushion block, connect by flange, in the time that cushion block height arrives 1.0 meters, increase by a joint steel pipe support in order to replace temporary cushion block, to strengthen stability of strutting system.Between braced structures, link firmly, between bolt between temporary cushion block, steel pipe support and jacking base bolt, steel pipe support and be all connected with bolt between temporary cushion block.Guarantee that by above measure braced structures has good globality, prevent from causing because of the contingent slippage of bridge beam body jacking the unstable failure of support system.
Steel supports composition jacking bracket systems such as adopting accurately machined tool type steel pipe support, and bracket system is connected with jacking base by the method for bar planting, and is unified into an entirety by bridging etc., has good globality and stability; Make to connect to an entirety in the support system jacking process of every side, increase the integral rigidity of synchronization of jacking up.
4. anchor point and bridge arch, wall cutting
After all preparation completes, jack is carried out to punching press 60%, make it tentatively stressed, then utilize rope saw to being connected between anchor point and bridge arch and abut carrying out cutting and separating, it is all thrown off.Cutting absolute altitude position between lifting platform and jacking base.
5. jacking is prepared
(1) jack-up system certificate authenticity
The certificate authenticity of element: the quality of element is the basis of mass of system, reliable for guaranteeing element, the element that native system is selected is quality product or the international top-brand product of Enerpac.Implement before jacking formal, by the pressurize 5 hours at the scene of the top lift with 70%-90%, reaffirm the reliability of sealing.
The reliability of system: hydraulic system is carried out the full loading test of 31.5MPa 24 hours transporting to before scene, carry out 0-31.5MPa cyclic test, makes system fault-free without leakage.
The cleannes of hydraulic oil: the cleannes of hydraulic oil are that system guarantees reliably, the design of native system and assembly technology, except in strict accordance with polluting the design criterion of controlling and technological requirement carries out, connecting hose is strictly being rinsed, after sealing, move to scene, scene installs carries out no-load running, to get rid of in site assembly process, and the dirt that may surprisingly sneak into.The cleannes of system should reach NAS9 level.
The stability of power closed loop: so-called power closed loop is exactly that the error of power is in 5% when default is well after certain power, and when power exceedes after this scope, system is adjusted to the scope of setting value automatically; Power closed loop is the basis of native system, and the debugging of power closed loop utilizes dead point pressurization, is undertaken by platform.
The stability of position closed loop: so-called position closed loop is exactly to set after top lifting height to grating scale when system, when exceeding this height system, top lifting height is automatically down to this height, when top lifting height rises to this height automatically lower than this height system, guarantee safety and the synchronism of system jacking.
(2) jacking control area is divided and hydraulic system layout
Control area is divided into 6 regions.The division principle at control point is that jacking process safety is reliable, the attitude control of the synchronism that stresses and pontic.
Control area arranges the synchronism of displacement transducer control displacement, and according to the structure of bridge, displacement synchronous precision is controlled at 2mm.Thereby being connected to form the closed-loop control of displacement, displacement transducer and central controller realize the accurate control of displacement in jacking process.
(3) pumping plant is installed
2 of jacking pumping plants make the economical rationality of jack oil length of tube as far as possible.
(4) jack-up system structure division checks
Whether a, jack are installed firmly vertical;
Whether b, lifting-up support are installed firm;
Whether c, position limiting structure are installed firm, and whether the spacing value value of establishing size meets the requirements;
D, affect the whether complete removal of facility of jacking;
Whether all e, agent structure were removed with being connected of other structure.
(5) jack-up system debugging
The main contents of debugging comprise:
A, hydraulic checking system;
B, control system inspection;
The setting of c, initial value with read.
6. weigh
(1) pressurize test
It is errorless that a, oil cylinder, oil pipe, pumping plant console, monitor etc. install inspection;
B, 70%~90% pressurization of pressing calculating load, carry out the pressurize of oil cylinder and test 5 hours;
The working condition of c, inspection whole system, oil circuit situation;
(2) weigh
A, for guaranteeing synchronously carrying out of jacking process, before jacking, should measure the actual loading at each Jacking point place
B, while weighing according to calculating jacking load, adopt the mode loading step by step to carry out, in certain top lifting height (1 ~ 10mm), by repeatedly adjusting the oil pressure of each group, can set one group of jacking oil pressure value, make the jacking pressure on each summit and its upper load in a basic balance.
C, for observe jacking place whether depart from, need measure its stroke with dial gage.
D, by the measured value of every and calculated value comparison, calculate its measures of dispersion, jointly analyze reason by hydraulic engineer and structural engineer, finally organize a reference value while determining that can this measured value serve as jacking by leader.As differ greatly, will be adjusted accordingly.
7. deliver for a check a little determine
On the bridge floor of each anchor point, get 3 monitoring points, 2 a bit, on center line, are respectively used to monitor absolute altitude and the midline position variation of jacking process Bridge in bridge floor both sides, and delivering for a check a little after finishing as jacking.Before jacking, should record relief initial value, so that jacking is checked after completing.
8. examination jacking
In order to observe and examine the duty of whole jack-up construction system and the check to weighing results, before formal jacking, should try jacking, examination top lifting height 10mm.
After examination jacking finishes, provide the situations such as overall attitude, displacement structure, for formal jacking provides foundation
9. formal jacking
After examination jacking, if observe no problem, just carry out formal jacking, jack range is 140mm, and each jacking standard stroke is 100mm, maximum jacking speed 10mm/min.
Six, connect high construction
After bridge jacking completes, carry out abutment bearing 41 and connect height and build, new impost connects height and builds.Connecing height is undertaken by following scheme:
Should be first before implementing to increase on truncation surface cut the concrete of 30cm left and right height, and column the old and new concrete bound fraction is carried out to surperficial dabbing processing, be beneficial to the connection of the old and new's concrete.After concrete cuts, must clean by water, must not leave dust and foreign material.
Reinforcement construction: according to former design drawing, increase main muscle and the stirrup welding of the quantity such as the employing of spreading part and original structure same specification.Reinforcing bar in arch rib is directly anchored at and newly waters in platform.
Template construction: steel form is by designing and producing, and " horn mouth " shape is made on top, to facilitate concrete building.
Concreting:
1. precast concrete block together in the time that Di Dun builds, 48 of concrete block size 200*200*200,4 of 200*200*240, now do temporary supporting when removing jack and steel pipe, the folded height of concrete block does four temporary support columns, directly pours into and connects in high concrete after removing jack and steel pipe.
2. connect high concrete and adopt slow setting, slightly expanded concrete, slow blowing in concrete casting process, and puddling reality is watered in layering.By total concrete consumption, extrapolate the height of building concrete, be one deck every 30cm left and right, guarantee the density of every layer of concrete smashing of water.
Seven, bearing is installed
The high part of concrete joint has been constructed, and concrete curing reaches after design strength, gets final product erection support, and beam falls.
After bearing is installed, next just carry out bridge check in place, recover bridge floor and connect, remove the operations such as jacking temporary structure, these are all the conventional operations of bridge jacking, have not just repeated here.