steel shed the lifting speed is generated by the inconsistent between the beam bodies internal stress interaction complex.According to past experience, every piece of lifting beam between the maximum lifting height control in average height of 1 mm or less, can guarantee the beams and continuous slab-deck structure safety.Due to the traditional lifting process is improved, so the lifting equipment is adjusted accordingly, Jack should be placed at the beam end horseshoe, the past design without much consideration after the lifting bearing replacement spacing, at the site of the field reconnaissance and found the beam end, horseshoe and coping at the top of the pitch in the 7.8 general to 8.8 cm, so Jack thickness should not only meet the space requirements, but also meet the requirement of lifting stroke (replacing support),
To this end, we contacted the professional Jack manufacturers, specializing in the production of the special-shaped jack.The same pier 10 jacks use 1 sets of pump control, thus 10 jacks synchronization.The present bridge single every hole consists of 5 pieces of T beam.Each beam weight includes the whole layer of bridge deck pavement and bumpers, weight.One of the dead weight of the beam aggregate 43 tons, edge beam weight aggregate 46 tons.Folding each bearing under self-weight load for middle beam 211 kn, edge beam of 225 kn.Using 150 tons of Jack, each beam bottom arrangement 1, relative to the load beam is about 7 times the safety coefficient, edge beam is about 6.5 times the safety coefficient, the bearing capacity is enough.The actual beam construction measurement of pump pressure of about 40 mpa.The construction steps of traditional work generally consider the erection bracket system form working platform, support system, adopted for lifting hydraulic system, operator and all quality by the tie beam, slab or foundation directly bear.Considering the engineering schedule and site conditions, the traditional process for improvement of the beam end, arranged for workers to operate the work platform - light hanging basket, basket field processing, at the same time, hanging basket mounted on both sides of the handrail, and ensure construction safety.The cap top surface and bottom surface of the beam body put Jack position steel shed, to ensure both surfaces are parallel; according to Jack the layout principle of its respective position; the oil pump machine is arranged in a good field of view position; according to a direction identification, easy to control principle,
jack
Oil pipe and oil valve connected in order.Installation pipe should pay special attention to inspection of tubing joints found dirt should be cleaned, to avoid lifting plug oil pump or oil.Jack is installed before the need for a trial run and debugging, to provide certain top lift its rate of roughly the same, error control in 1 mm.Check before installation jack and sealing, to ensure Jack good seal, oil and oil quantity to meet the requirements of varieties.After the examination, manual installation and adjustment in the jack, Jack pretravel, ensure the jack and the cushion block between close.General insurance block by steel plate, planar size should not be less than the total height of the 2/3, to ensure that the case role pad not instability.All the preparations are available after (such as inspection pad, Jack installation, bearing the basis of legislation, all construction equipment and materials etc.), Jack to simultaneously actuate, try to top, according to lifting stroke is lifting control.After unloading shall carefully check the system respective control system and epigenetic phenomena, check the key: all the oil has no leakage, Jack has no abnormal phenomenon, power supply lines and apparent wear.After unloading at the same time also should check the jack plate has no deformation, when necessary, can adjust the thickness of the sheet to meet the jacking requirement; check Jack position under the structure has no difference from the lift before the event, such as the existence of, should be carefully to find out why before the formal lifting, no case unknown continued jacking.Try top end, the professionals under the unified command of all Jack slowly force whole jacking beam,
When the top lifting synchronism rises, each top with displacement between hierarchical control, the piers and abutments to radio contact, began in 3 millimeter level, each level in place after the uniform stop, padded steel stool and steel, check the top case, ensure good working condition before proceeding to the next stage lift, so repeatedly.Lifting height above the support design height of 20 mm.In order to ensure that each piece of beam uniformity synchronous rise gradually to the upper top beam, classification, various height of 3 mm, from the top to the construction requirements of height, pad groove plate bench, and in the steel shed jacking process of complete measurement, recording work, ensure that the girder, bridge bearing replacement repair consistent.As a result of new old bearing height ranging from as far as possible, take on the same pier uniform replacement of all support measures, to ensure the same pier all support the same height.Demolition of old support, cleaning up old support around the debris; the beam bottom steel plate rust rust and antirust processing; epoxy material pad bearing pad stone and beam bottom surface is not parallel to part (both in horizontal plane shall prevail); according to the accurate position of the installation of the new support lofting.Construction process control measures of bearing replacement need top up the entire span bridge, enhance the capacity, enhance the speed, displacement control is strict, glue River Bridge at the most need dozens of Jack synchronous operation, at the same time insurance block change, replacing the bearing, displacement measurement, the oil valve control needs more skilled workers in a relatively short period of time in a tacit understanding with homework.Thus on the whole process control is particularly important.Top beam before operation must be prepared for all the equipment and materials.The oil pump, oil pipe and each jack to do maintenance and debugging.The site must have enough wearing parts and spare materials.The new support, epoxy self-leveling material and its preparing tools must be at the scene ready, and staff for.Top beam work must do all workers training, for every worker must confirm their responsibilities and proficiency.Personnel must be thoroughly familiar with the top command process in all aspects, as well as matters needing attention and emergency countermeasures.Before operation should first check personnel, equipment and materials to and normal use.The implementation of jacking focus when control of pump and valve division division personnel, strictly in accordance with predetermined step steel shed command operations, in each stage were carefully check the hydraulic condition, vertical displacement of beam body.Rubber bridge bearing replacement of the whole process of construction smoothly, the construction speed is faster, without any accidents.In the process of bridge bearing replacement, without interruption, jacking process and jacking construction monitoring shows that after the completion of the bridge deck pavement, bridge structure includes did not show any abnormalities.Therefore, glue river bridge bearing replacement of successful experience, to the same type of simply supported bridge bearing replacement construction is had draw lessons from action.
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