CN101186273A - The Method of Lowering Overweight Structures by Two Jacks in Series - Google Patents

Abstract

The invention provides a construction method which can carry out the integration dropping-down of overweight structures such as movable formwork, etc. by adopting normal jack, steel strand, etc. The invention is characterized in that after the construction of box girder is implemented, two reaction frames are assembled on the bridge by bailey beam or section steel and the normal perforation jack is adopted to carry out the integration dropping-down of the movable formwork; two perforation jacks fixed on the reaction frame are connected in series to form a fulcrum power device; the two jacks alternatively transfer external force in order to implement continuous operation.

Description

The Method of Lowering Overweight Structures by Two Jacks in Series

technical field

The invention relates to a construction method for integrally lowering overweight structures by using ordinary jacks in the construction of bridges or tall buildings.

Background technique

At present, more and more prestressed continuous box girders are used in the superstructure of bridges with a span of 30 to 50m. It is most economical and efficient to use the mobile formwork (ie bridge building machine) method in the construction of the superstructure of such bridges. Fast, and easy to ensure the construction quality of the box girder. Especially in the construction in mountainous and hilly areas, compared with the traditional full house support method, a large number of steel pipe supports and formwork are saved, and the construction progress is greatly accelerated. Therefore, the formwork is usually made relatively large, and it is quite difficult and unsafe to disassemble at a high altitude. It is very expensive to ask a professional company to lower the overall structure of the overweight structure. And no matter how decentralized it is, the disassembly still needs to be done by yourself. It is quite expensive to buy special decentralized equipment, and the versatility is not strong, and the frequency of use is not high, which is also relatively wasteful. Lifting equipment is used to realize the overall lowering of overweight structures such as large mobile formwork.

Contents of the invention

The purpose of the present invention is to reduce the waste of resources, realize the disassembly of large-scale construction equipment such as mobile formwork (bridge building machine) on the ground, and safely and quickly realize the overall lowering of the formwork to the ground for easy disassembly. A construction method that realizes the overall lowering of large-tonnage structures for auxiliary facilities such as tools and steel strands.

The technical solution adopted by the present invention to solve its technical problems is:

A method for lowering an overweight structure with two jacks connected in series. It is a method for dismantling a mobile formwork. Its features: after the construction of the box girder is completed, two reaction frames are first assembled on the bridge with Bailey sheets or section steel. Conventional through-hole jacks are used to lower the mobile formwork as a whole, and two through-hole jacks fixed on the reaction frame are connected in series to form a lifting point power device, and the two jacks alternately receive external forces to realize continuous operation.

The steps of connecting two through-hole jacks in series to form a lifting point power device are as follows: assemble the reaction force frame at the calculated lifting point position, place the working anchorage of the through-hole jack machine on the jack base of the reaction force frame, Install the lifting point anchor beam at the lifting point of the longitudinal beam of the mobile formwork, pass the steel strand through the anchor plate of the lifting point anchor beam and the two coaxial jacks and working anchors on the reaction frame in turn and tighten them Steel strand, after all the hoisting equipment is installed at all lifting points, oil is supplied to the jacks above each lifting point at the same time, so that the entire mobile formwork is separated from the original support device, and the original support system is removed, and the lower jack is released at the same time The upper working anchor clip, and push the piston to the maximum stroke, and then return the oil to the jack above each lifting point at the same time, and the formwork starts to lower.

The steps for the two jacks to transfer external force alternately are: when the piston stroke of the upper jack is close to zero, stop the oil return and push the piston of the lower jack to near the maximum stroke, and anchor the supporting working anchor Safe, then continue to return the oil to the upper jack, and transfer the tension of the steel strand to the lower jack. When all the external force borne by the upper jack is transferred to the lower jack, loosen the upper working anchor and put it The piston is pushed to nearly the maximum stroke position, ready to take over the external force suffered by the jack below. The number of reaction frames, jacks, steel strands and the location of lifting points must be determined according to the actual lifting weight calculation.

In addition to being applicable to the disassembly of large construction equipment such as the above-mentioned mobile formwork (bridge building machine) on the ground, the present invention can also be applied to the transfer and disassembly of components in the construction of tall buildings.

The beneficial effect of the present invention is that a conventional jack and matching simple tools can be used to safely and quickly lower the structure with enlarged tonnage. Save time and equipment, improve efficiency.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is an overall schematic diagram of the overall lowering of the mobile formwork of the present invention.

FIG. 2 is a side view of FIG. 1 .

Part numbers in the figure: 1. Reaction frame, 2. Through-hole jack and working anchorage, 3. Steel strand, 4. Lifting point anchor beam, 5. Mobile formwork.

Detailed ways

In Figure 1 and Figure 2, one end of the steel strand is anchored on the lifting point with a squeeze anchor, and the other end passes through two through-hole jacks and working anchors at the same time, and the external force is alternately transmitted through the two jacks to realize the movement of the mold. The overall lowering operation of overweight structures such as racks. Assemble the reaction force frame (1) at the position of the lifting point determined by calculation, place the working anchorage (2) of the through-hole jack machine on the jack base of the reaction force frame (1), and hang it on the longitudinal beam of the mobile formwork (5) The lifting point anchor beam (4) is installed at the lifting point position, and the steel strand (3) passes through the anchor plate of the lifting point anchor beam (4) and the two coaxial jacks on the reaction force frame and the working anchorage (2 ) and tighten the steel strands (3), and after all the hoisting equipment at the lifting points are installed, oil is supplied to the jacks (2) above each lifting point at the same time, so that the entire mobile formwork (5) is separated from the original supporting device , and remove the original support system. At the same time loosen the working anchor clip on the jack (2) below, and push the piston to the maximum stroke, then return the oil to the jack (2) above each lifting point at the same time, and the formwork (5) starts to lower, when the upper one When the piston stroke of the jack (2) is close to zero, stop the oil return and push the piston of the lower jack (2) to near the maximum stroke, and anchor the supporting working anchors securely, and then continue to return the oil to the upper jack (2). oil, and the tension of the steel strand is borne by the jack (2) below. When the external force borne by the jack (2) on the top is all transferred to the jack (2) on the bottom, the working anchorage on the top is released, and its piston is pushed to a position close to the maximum stroke, ready to take over the external force suffered by the jack on the bottom. Alternate delivery in this way realizes the overall lowering operation of the mobile formwork.

Claims (3)

1. the method for a lowering overweight structure by connecting two jacks in series, it is the method that a kind of mobile formwork is removed, it is characterized in that: after box girder construction is finished, earlier with shellfish thunder sheet or shaped steel assembly unit twice reaction frame on bridge, adopting conventional punching jack to carry out mobile formwork integral body transfers, form a suspension centre engine installation by two punching jack series connection that will be fixed on the reaction frame, two jacks alternately connect passs external force, realizes continuous working.

2. the method for lowering overweight structure by connecting two jacks in series according to claim 1, it is characterized in that: the step that two punching jack series connection are formed a suspension centre engine installation is: the good reaction frame of determining in calculating of hoisting point position assembly unit (1) is placed in punching jack machine work ground tackle (2) on the jack base of reaction frame (1), longeron hoisting point position at mobile formwork (5) installs suspension centre anchor beam (4), steel strand (3) are passed anchor plate and two the coaxial jacks and the work ground tackles (2) on the reaction frame of suspension centre anchor beam (4) successively and tighten up steel strand (3), treat that whole suspension centre weight-lifting equipments install, send oil for simultaneously each jack (2) above the suspension centre place, make whole mobile formwork (5) break away from original bracing or strutting arrangement, and remove former support system, unclamp the work anchor intermediate plate on the following jack (2) simultaneously, and piston is pushed into range, give jack (2) oil return of each suspension centre top then simultaneously, mould bases (5) begins to transfer.

3. the method for lowering overweight structure by connecting two jacks in series according to claim 1; it is characterized in that: two jacks alternately connect pass external force step be: when the jack in top (2) piston stroke near zero the time; suspend oil return and the piston of the jack (2) of bottom is pushed near range; and the work ground tackle anchoring that it is supporting is safe; continue to give jack (2) oil return of top then; the tension force of steel strand is transferred to following jack (2) to be born; treat to unclamp when external force that the jack (2) of top is born is all transferred to following jack (2) the work ground tackle of top; and its piston is pushed into maximum travel position nearly, prepare to take over the following suffered external force of jack.

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