CN106436573B - Construction method of steel truss support for super high cable tower with large span upper beam corbel - Google Patents

Abstract

This invention relates to a construction method for a steel truss bracket support for the upper crossbeam of a super-high cable tower with a large span, belonging to the field of building construction technology. The method includes the following steps: installing embedded parts, installing lifting equipment, lifting the steel truss, installing the bracket support, and lifting and fixing the entire structure into place. The construction method for the steel truss bracket support for the upper crossbeam of a super-high cable tower with a large span provided by this invention effectively solves the problem that existing methods often use ground-mounted supports for the upper crossbeam, and that ordinary large-span upper crossbeams without ground-mounted bracket supports are prone to causing displacement of the large cantilever flexible cable tower during construction, affecting construction quality. This method features low investment, short construction period, low safety risk, and an orderly and controllable construction process, providing a reference for similar bridge construction.

Description

Construction method of steel truss support for super high cable tower with large span upper beam corbel

technical field

The invention relates to a construction method for a large-span upper beam corbel steel truss support of a cable-stayed and suspension bridge, and belongs to the technical field of bridge construction.

Background technique

Since the 1970s, cable-stayed bridges and suspension bridges have been applied all over the world, and developed rapidly in the 1990s. my country's cable-stayed bridges and suspension bridges are currently developing in the direction of super-high, heavy-load, complex and long-span. Cable towers are the main load-bearing components of cable-stayed bridges and suspension bridges. H-type cable towers are widely favored by designers because of their simple structure, excellent bearing capacity, and clear force characteristics. They have been more and more widely used in large bridges in my country. under construction.

Most of the H-shaped cable towers used in modern bridges have the characteristics of inward inclination of the middle and upper tower columns, relatively small spacing between the lower and upper beams, and the span and height of the lower beams are larger than the upper beams. Super-high H-shaped cable towers may be installed Multiple beams. The upper beam of this type of H-type cable tower can be constructed with traditional floor-standing steel pipe supports, that is, the completed lower beams are used as the temporary support load-bearing system of the upper beams. The construction process is simple, the support has a large bearing capacity, and the safety factor is relatively high.

Considering the appearance and shape of the cable tower structure, and taking into account the amount of engineering investment, some H-shaped cable towers are designed with no slope change inside the double tower limbs, the design position of the upper beam is high, the span is large, the amount of concrete is large, and the clear distance between the upper and lower beams is large. features. If the above-mentioned H-type cable tower is constructed with traditional floor-standing steel pipe supports, there are many defects as follows:

1. The processing and installation period of the steel pipe column is long. During the installation process, the tower crane is occupied for a long time, which affects the construction of the main structure of the tower limb, and the subsequent demolition workload is huge;

2. It is difficult to control the verticality and overall stability of the ultra-long steel pipe column installation;

3. The amount of materials used is large, the investment is large, and the economy is poor.

The above-mentioned H-type cable tower should be constructed by using the method without floor supports. In the existing public technology, such as the publication number: CN104109999 A "Construction Method for Bridge Tower Beams", which introduces a kind of H-type cable tower multi-beam without floor support construction. The method, the technical method is: hoist the beam support to the construction position of the upper beam, complete the construction of the upper beam, then pass the beam support under the through-hole jack to the construction position of the middle beam, and after the construction of the middle beam is completed, then lower the beam support to Ground demolition. However, this technology only emphasizes the installation method and does not specifically involve the structure and layout of the beam bracket. At the same time, the weight of the beam bracket on the long-span is relatively large. The top beam construction position.

For example, the publication number: CN 103352428 A "Construction Method for Cable Tower Crossbeam of Suspension Bridge without Support", introduces a construction method for suspension bridge cable tower beam without support. The technical method is: welding a steel truss, installing a suspension system on the steel truss, Use the suspension system to lift and fix the bottom form. This technical method pours the steel truss into the beam as a permanent structure, which may affect the overall structural properties of the beam and cause material waste, which has certain limitations.

Contents of the invention

The technical problem to be solved by the present invention is to propose a construction method for a super-high cable tower large-span upper beam corbel steel truss support without a floor-type rigid support.

In order to solve the above-mentioned technical problems, the technical solution proposed by the present invention is: a construction method for a super-high cable tower large-span upper beam corbel steel truss support, wherein the corbel steel truss support includes a steel truss and a corbel support; the method includes the following step:

(1) During the construction of the bridge tower column, according to the installation position of the corbel steel truss bracket, the corbel support embedded parts, lower chord embedded parts, upper chord embedded parts and lifting bracket pre-embedded parts are reserved in sequence. Embedded parts;

(2) Weld and install the lifting bracket on the embedded parts of the lifting bracket; install the through-type continuous jack on the lifting bracket;

(3) Hoist the steel truss finished on the ground as a whole to the top of the lower beam of the bridge tower column, the through-type continuous jack penetrates the steel strand, and the bottom of the steel strand is connected with the hoist on the steel truss. point connection;

(4) Start the through-type continuous jack, lift the steel truss to a height that can accommodate the corbel support between it and the lower beam of the tower column, and temporarily fix the steel truss on the on the pylon;

(5) hoisting the corbel support that has been processed on the ground below the steel truss, and welding it with the steel truss to form the corbel steel truss support;

(6) Release the temporary fixation between the steel truss and the bridge tower, and start the through-type continuous jack to lift the corbel steel truss support below the installation position;

(7) Start the through-type continuous jack, lift the corbel steel truss support to the design position, and weld and fix it with the embedded parts;

(8) Load-bearing fulcrums are installed on the corbel support embedded parts, and the corbel steel truss supports on the tower columns on both sides of the bridge are connected into a whole by using a transverse connection system.

A further improvement of the above solution is that: the corbel support is a rigid corbel support composed of steel structure slanted legs and parallel connections between the slanted legs.

A further improvement of the above solution is that: the steel truss is composed of an upper chord, a lower chord, a vertical bar and a diagonal bar.

The construction method of the super-high cable tower large-span upper beam corbel steel truss support effectively solves the problems of large investment, long period, high risk and difficult control in the existing upper beam construction method that mostly adopts floor-standing brackets. A reference is provided for similar bridge construction. Super-high cable tower large-span upper beam corbel steel truss support The support adopts a non-floor rigid support structure, which does not require preloading tests before construction, shortens the construction period, and has large bearing capacity, clear force transmission path, and stable structure , easy installation and disassembly, etc. The processing and assembly of steel trusses and rigid corbels are all completed on the ground, which reduces high-altitude operations and greatly increases construction safety. Promote and facilitate. At the same time, the innovative design, development and application research carried out in this field make the super-high cable tower large-span upper beam corbel steel truss bracket and construction method have a wider promotion value.

Description of drawings

Fig. 1 is a schematic structural diagram of a preferred embodiment of the present invention.

Figure 2 is a schematic diagram of the completed structure of step (3).

Fig. 3 is a schematic diagram of the completed structure of step (5).

Fig. 4 is a schematic diagram of the completed structure of step (6).

Figure 5 is a schematic diagram of the corbel and steel truss structure.

FIG. 6 is a schematic side view of the structure of FIG. 1 .

The symbols in the figure are as follows: Z1-steel truss, Z2-corbel support, Z3-embedded system, Z4-lifting system, 1-top chord, 2-bottom chord, 3-vertical bar, 4-slanting bar, 5 -Steel truss connecting beam, 6-slanted legs of both legs, 7-flat connection, 8-embedded part of corbel support, 9-embedded part of lower chord, 10-embedded part of upper chord, 11-embedded lifting bracket pieces, 12-lifting bracket, 13-through-heart continuous jack, 14-temporary cross brace of tower column.

Detailed ways

Example

The super-high cable tower large-span upper beam corbel steel truss support construction method of the present embodiment comprises the following steps:

(1) As shown in Figure 1, during the construction of the bridge tower column, according to the installation position of the corbel steel truss bracket, the corbel support embedded parts 8, lower chord embedded parts 9, Upper chord embedded parts 10 and lifting bracket embedded parts 11;

(2) Weld and install the lifting system Z4 on the lifting bracket embedded part 11; the lifting system Z4 includes: the lifting bracket 12 welded and fixed with the lifting bracket embedded part 11 and the through-type continuous jack 13 installed on the lifting bracket 12;

(3) As shown in Figure 2, hoist the steel truss Z1 that has been processed on the ground to the top of the lower beam of the bridge tower. The steel truss Z1 is connected by a horizontal connection system, and the continuous jack 13 is inserted into the steel strand. The bottom of the steel strand is connected to the lifting point on the steel truss Z1;

(4) As shown in Figure 3, start the through-type continuous jack 13, lift the steel truss Z1 to a height that can accommodate the corbel support Z2 between it and the lower beam of the bridge tower column, and temporarily place the steel truss Z1 outside On the corbel stretcher;

(5) As shown in Figure 3, the corbel support Z2 that has been processed on the ground is hoisted under the steel truss Z1, and welded with the steel truss Z1 to form an integral corbel steel truss;

(6) As shown in Figure 4, remove the temporary fixation between the steel truss Z1 and the bridge tower column, and start the through-type continuous jack to lift the steel truss Z1 and the corbel support Z2 to the installation position;

(7) Start the through-type continuous jack 13, lift the corbel steel truss support to the design position, and weld and fix it with the embedded parts.

(8) Load-bearing fulcrums are installed on the corbel support embedded parts 8, and the corbel steel truss supports on the tower columns on both sides of the bridge are connected into a whole by using a steel truss connection system 5.

Subsequent tasks such as dismantling the through-type continuous jack 13 will not be repeated.

In the above method, the steel truss Z1 is composed of upper chord 1, lower chord 2, vertical rod 3, and oblique rod 4, as shown in Figure 1 and Figure 5, and the steel truss Z1 is connected as a whole by steel truss connecting beam 5 , wherein, both ends of the upper chord 1 and the lower chord 2 have an embedded part system Z3 that cooperates with the lower chord embedded part 9 and the upper chord embedded part 10 . In order to cope with the dimensional changes caused by thermal expansion and contraction, the size of the upper chord 1 and the lower chord 2 should be slightly longer than the design length. Then, in step (7), firstly, select a constant temperature period and measure the upper chord several times. According to the measurement results for the closing width of the rod 1 and the lower chord 2 and the length of the steel truss Z1, the upper chord 1 and the lower chord 2 are matched and cut on site.

As shown in Fig. 1 and Fig. 5, the corbel support Z2 is composed of oblique legs 6 and parallel joints 7 of both limbs.

The lower chord embedded parts 9, the upper chord embedded parts 10 and the lifting bracket embedded parts 11 are buried during the construction of the tower columns on both sides of the bridge, and the load of the upper beam is transmitted to the tower body through the embedded parts system. The length of the exposed end of the embedded part at both ends of the upper chord 1 of the steel truss Z1 is 0.5m, and the length of the exposed end of the embedded part of the lower chord 2 is 0.3m; the steel truss Z1 is processed into a trapezoid, and the lower chord 2 is slightly longer than the upper chord 1, namely The upper chord 1 is 0.5m shorter than the design on one side, and the lower chord 2 is 0.3m shorter than the design on one side. In this way, it can be ensured that the steel truss Z1 can be lifted smoothly to the design position during the in-situ overall lifting process. Due to the trapezoidal design of the steel truss Z1, in order to prevent the lifting from being too wide at the bottom, the corbel embedded part 8 on the corbel support Z2 should be installed after the overall lifting is in place.

As shown in Figures 1 to 4, if the lifting process of the steel truss Z1 forms space interference with the design position of the temporary cross brace 14 of the tower column, the steel truss Z1 can be divided into left and right parts as shown in Figure 5, and the steel truss Z1 will not be installed temporarily. The truss connecting beam 5 is then divided into two parts, and can be lifted from the top of the lower beam to the design position as a whole.

The present invention is not limited to the specific technical solutions described in the above embodiments, and all technical solutions formed by equivalent replacement are within the scope of protection required by the present invention.

Claims (3)

1. a kind of superelevation Sarasota large span upper beam bracket steel truss stand construction method, the bracket steel truss holder includes steel truss And corbels support；This approach includes the following steps：

（1）In bridge king-post work progress, according to the installation site of the bracket steel truss holder, it is pre- that corbels support is reserved successively Embedded part, lower boom built-in fitting, top boom built-in fitting and lifting bracket built-in fitting；

（2）The welding installation lifting bracket on the lifting bracket built-in fitting；It is continuous that punching is installed on the lifting bracket Jack；

（3）At the top of the steel truss integral hoisting that ground is machined to the bottom end rail of the bridge king-post, the punching connects Continuous jack penetrates steel strand wires, and the steel strand wires bottom is connect with the suspension centre on the steel truss；

（4）Start the punching continuous jack, by the steel truss be promoted to its bottom end rail with the bridge king-post it Between can accommodate the height of the corbels support, and the steel truss is temporarily fixed on the bridge king-post；

（5）The corbels support that ground machines is lifted to below the steel truss, and with the Welding steel truss group At the bracket steel truss holder；

（6）Being fixed temporarily between the steel truss and the bridge king-post is released, and starts the punching continuous jack, Below the bracket steel truss support lift to installation site；

（7）Start the punching continuous jack, by the bracket steel truss support lift to design position, and utilizes the ox The bracket steel truss holder is weldingly fixed on the bridge tower by leg supporting embedded part, lower boom built-in fitting and top boom built-in fitting On column；

（8）Load-bearing fulcrum is installed on the corbels support built-in fitting, using lateral connection system by the bridge of bridge both sides Bracket steel truss holder connection on king-post is integral.

2. superelevation Sarasota large span upper beam bracket steel truss stand construction method according to claim 1, it is characterised in that：Institute State the rigid corbels support that corbels support is made of the lateral between double limb battered legs of steel construction and the battered leg.

3. superelevation Sarasota large span upper beam bracket steel truss stand construction method according to claim 1, it is characterised in that：Institute Steel truss is stated to be made of top boom, lower boom, montant and brace.