CN107299713A - A kind of circular cone roofing integrally-lifting steel truss and its construction - Google Patents

Abstract

This invention discloses an integral lifting steel truss for a conical roof and its construction method. The steel truss mainly consists of a central disc (1), main frame (2), upper line members (3), lower chord members (4), tie rods (5), and diagonal bracing members (16). The construction method includes the following steps: truss design and fabrication; truss assembly; initial overall lifting of the truss by 2m; installation of the lower operating scaffold of the truss; truss lifting; installation of corbels and secure connection with the truss; erection of the upper support frame and binding of reinforcing bars; pouring concrete; and dismantling and removing the truss after the concrete strength reaches 100%. This integral lifting steel truss has a significant time efficiency improvement, and the steel truss replaces the full-span support frame, reducing the large investment and erection of turnover materials. The installation and dismantling process of the steel truss is simple and easy to operate. The steel truss also features the characteristic of one-time investment and multiple reuses.

Description

A conical roof integral lifting steel truss and its construction method

technical field

The invention relates to an integral lifting type steel truss on a conical roof and a construction method thereof, belonging to the technical field of construction engineering.

Background technique

The design of the central storage grain storage mostly adopts the silo structure, which is convenient for the application of slip-form construction technology. There is no specific requirement for the roof design, and most of them adopt conical and curved shapes. There is no uniform requirement for the corresponding roof construction. Common roof support frame construction methods are: The construction method of setting up support frame and steel truss as support frame on full hall support frame, steel platform.

The integral steel truss is a supporting system designed according to the characteristics of the conical roof, which consists of the main body of the truss, the lifting and lowering of the truss, and the supporting structure. Its characteristic is that a steel truss is designed to transmit the loads of formwork, concrete, steel bars, etc. to the supporting corbels through the steel truss. The construction process is as follows: the staff assembles the steel truss on the bottom of the warehouse. After the truss is assembled, the electric hoist is used to lift it to the position of the corbel. After reaching the design strength, the steel truss is lowered as a whole, and the steel truss is removed from the bottom plate. This construction method has great potential for development.

Contents of the invention

The object of the present invention is to provide a conical roof integrated lifting steel truss and its construction method, so that the force of the conical roof integral lifting steel truss structure is reasonable, the construction method is simple and easy to operate, so as to overcome the shortcomings of the prior art.

Technical scheme of the present invention is such:

The present invention firstly proposes a conical roof integrated lift-type steel truss, which includes a central disc, and a disc-shaped floor is arranged above the central disc, and the diameter of the disc-shaped floor is larger than the diameter of the central disc. The projection of the center of the disc-shaped floor on the central disc coincides with the center of the central disc; a number of main rods extend from the semicircle part of the disc-shaped floor to the plane where the central disc is located. The pole frames are evenly distributed in the circumferential direction on the axis of the connection line between the disc-shaped floor and the center of the central disc; on the other side of the disc-shaped floor, a number of rods are extended to the plane where the central disc is located. The upper chord member corresponding to the main rod frame on the opposite side; the connection point between the main rod frame and the upper chord member on the plane where the central disc is located forms a complete large disc, the diameter of which is larger than that of the disc type The diameter of the floor; the above-mentioned three discs and the main rod frame, the upper chord member and other connecting rods that connect them together constitute the structure of the conical roof integral lifting steel truss.

Among them, other connecting rods include at least the lower chord member used to connect the large disk and the central disk, the tie rod used to connect the main rod frame and the central disk, and the inclined rod used to connect the central disk and the disk-shaped floor. Support rod.

The construction method of the integral lifting steel truss on the conical roof is used for the roof construction of conical silos with different diameters. The construction method includes the following steps: truss design and processing; The truss is lifted; the corbels are installed and firmly connected with the truss; the upper support plate of the truss is erected and the steel bars are tied;

Among them, after the construction of the round silo is completed, steel trusses are assembled on the bottom of the silo; the shallow round silo external scaffolding is used to support the gutter formwork as an operating platform, and hoisting hoist steel structure spreaders are installed on the top of the shallow round silo wall. Install the hoisting electric hoist, and the supporting hoisting hoist to connect the cables and the main control box; use the electric hoisting hoist to lift the truss to the design level, connect and fix the steel truss to the corbel, and complete the hoisting of the truss; after the concrete pouring reaches the design strength, the steel truss The electric hoist is used for dismantling the truss. The steel hinges of the electric hoist pass through the reserved holes on the roof panel of the silo, and are firmly connected with the steel structure frame and maintain the balance of the steel structure frame. tear down.

Among them, the truss assembly is carried out according to the following steps: After the steel truss is processed, it is transported to the construction site, re-inspected and numbered, and the truss parts are hoisted into the inner bottom plate of the conical silo by a tower crane, and the installation is carried out in the following order: Reinforce the frame bar →Main frame rod→Diagonal bracing rod→Central disc→Tie rod.

Among them, when the corbels are installed and firmly connected with the truss, the steps are as follows: use the outer scaffolding erected during the construction of the shallow round silo gutter as the operating platform, and install the hoisting hoist spreader and the supporting hoisting hoist connection cable on the top of the silo wall. For the main control box, use the outer scaffolding and the hanger under the steel truss to install the corbel at the reserved position on the warehouse wall.

The integral steel truss of the present invention is a supporting system designed according to the characteristics of the conical roof, and is composed of a truss main body, a truss lifting and a supporting structure. Its characteristic is that a steel truss is designed to transmit the loads of formwork, concrete, steel bars, etc. to the supporting corbels through the steel truss. The construction process is as follows: the staff assembles the steel truss on the bottom of the warehouse. After the truss is assembled, the electric hoist is used to lift it to the position of the corbel. After the design strength is reached, the steel truss is lowered as a whole, and the steel truss is removed from the bottom plate. This construction method has the advantages of reasonable structural force, simple and easy to operate.

The present invention has following technical effect:

First of all, the preliminary processing of the integral lifting steel truss does not occupy the direct construction period, and the installation and removal of the steel truss occupy a small amount of construction period, and the construction period effect is obvious.

Secondly, the steel truss replaces the supporting frame of the whole hall, which reduces the investment and erection of a large amount of turnover materials. The slope of the roof is determined during the processing of the steel truss, and the project quality is easily guaranteed.

Thirdly, the installation and removal process of the steel truss is simple and easy to operate.

Finally, the steel truss has the characteristics of one investment and multiple turnovers, which significantly reduces the construction cost of multiple conical roofs, and has good social benefits and development prospects.

Description of drawings

Fig. 1 is a steel truss elevation view of the present invention;

Fig. 2 is the upper chord plan view of the steel truss of the present invention;

Fig. 3 is the lower chord plan view of the steel truss of the present invention;

Figure 4 is the fixture installation diagram when the spreader and the corbel are installed;

Figure 5 is a side view of the spreader when the spreader and the corbel are installed;

Fig. 6 is an installation diagram of the corbel when the spreader and the corbel are installed;

Figure 7 is a cross-sectional view of the electric hoist steel beam when the steel truss is removed;

Fig. 8 is a plane view of unloading the electric hoist steel beam when the steel truss is removed.

Explanation of reference signs: 1-central disc, 2-main rod frame, 3-upper chord member, 4-lower chord member, 5-tie rod, 6-silo wall, 7-channel steel, 8-reserved lifting hole , 9-fixture bolts, 10-high-strength bolts, 11-hanging holes, 12-fixed steel plates, 13-I-beams, 14-reserved holes, 15-silo roof, 16-diagonal bracing rods.

detailed description

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

First look at Fig. 1, Fig. 1 shows the elevation view of the steel truss of the present invention, and Fig. 2 and Fig. 3 respectively show the plan view of the upper chord and the lower chord of the steel truss. It can be seen from Fig. 1 that a conical roof integral lifting steel truss includes a central disc 1, and a disc-shaped floor is arranged above the central disc 1, and the diameter of the disc-shaped floor is larger than that of the center. The diameter of the disk 1, the projection of the center of the disk-shaped floor on the center disk 1 coincides with the center of the circle of the center disk 1; A number of main rod frames 2 are extended, and the main rod frames 2 are uniformly distributed around the axis of the connection line between the disc-shaped floor and the center of the central disc 1; on the other side of the disc-shaped floor On the plane where the central disc 1 is located, several upper chord members 3 corresponding to the main rod frame 2 on the opposite side are extended; the main rod frame 2 and the upper chord member 3 are connected on the plane where the central disc 1 is Constitute a complete large disc, the diameter of which is greater than the diameter of the disc-shaped floor; the above three discs and the main rod frame 2, the upper chord member 3 and other connecting rods together form a conical The structure of the whole roof lifting steel truss. Among them, other connecting rods include at least the lower chord member 4 for connecting the large disc and the central disc 1, the tie rod 5 for connecting the main rod frame 2 and the central disc 1, and the tie rod 5 for connecting the central disc 1 and the central disc 1. Diagonal bracing bar 16 of dish type floor.

Example 1:

China Construction Fourth Engineering Bureau Co., Ltd. undertook the construction of the central grain reserve warehouse in Kunming. The project is located in Qingshan District, Jinning County Industrial Park, Kunming City. It consists of 12 shallow round warehouses with an inner diameter of 25m and supporting projects, with a storage capacity of 100,000 tons The granary (single-seat shallow round storage capacity is 8,350 tons), the roof of the silo is a reinforced concrete conical roof, a 200mm thick reinforced concrete roof panel, and the roof elevation is 32.97m. After the comparison of multiple schemes, the integral elevating steel truss of the present invention is used as the level formwork support system, which is completed through the implementation of the conical roof of 12 warehouses.

1. Construction sequence and main methods

(1) Steel truss design

1. The steel truss is designed according to the actual characteristics of the project, including the size of the central disc 1, the length and specification of the diagonal bracing rod 16, the length and specification of the main frame rod 2, and the length and specification of the tie rod 5, etc. The diameter of the silo, the height of the cone, and the thickness of the roof concrete are considered in the design to ensure the safety of the truss during construction and to save the amount of steel as much as possible.

2. Calculation tools, load cases and calculation models

2.1 Calculation tools

This construction method adopts the finite element software MIDAS for modeling analysis. The software can analyze and calculate the strength, stiffness and stability of the structure, and in the later processing, you can see the instability mode diagram, as well as the load----displacement The deformation process traces the curve.

2.2 Load Cases

Design concrete load calculation:

[2.238/40.698×3.14×4.512×(9.022+9.02×3.25+3.252)/3+10.337+22.55]

×24/491=3.12kN/ ^m2

Steel load calculation: 35×10/491=0.71kN/m ²

Design support frame load calculation: 1407×0.0358/491=0.11kN/m ²

Design formwork timber load calculation

615.99×0.085/491=0.11kN/m ²

Design construction load (excluding concrete weight) 2.5kN/m ²

Design total load: q=1.2×(3.12+0.71+0.11+0.11)+1.4×2.5=8.36kN/m ² , take 9kN/m ² for calculation.

The construction of temporary facilities does not count the effects of strong winds and earthquakes.

The structure is arranged as two circular rings, the upper one is smaller and the lower one is larger, and the rings are connected by radial section steel to form a circular platform system. The whole structure is divided into 20 symmetrical units, plus supporting rods to form a stable system.

2.3 Calculation model

Through the above finite element analysis results, it can be concluded that the maximum displacement of the steel truss platform in the X direction is 0.89mm, the maximum displacement in the Y direction is 0.893mm, and the maximum displacement in the Z direction is 16.95mm. It can be seen that the deformation is small and can meet the construction requirements. The maximum stress of the steel truss platform is 133.31MP, and the maximum stress occurs at the oblique beam in the center of the platform, which is less than the yield strength of the steel 235MP and 345MP. It can be seen that the steel platform can meet the bearing capacity requirements.

(2) Steel truss processing

After the design is completed, the processing of the truss is carried out. After the processing is completed, the trial assembly is carried out in the factory, and the components are checked and accepted. They can only be transported to the construction site after meeting the design requirements.

(3) Steel truss installation

The steel truss is transported to the construction site, re-inspected and numbered, and the truss parts are hoisted into the bottom plate of the warehouse by tower crane, and the installation is carried out in the following order: reinforced frame rod (upper chord member 3, lower chord member 4) → main frame rod 2 → Diagonal bracing rod 16→central disk 1→pull rod 5.

(4) Corbel measurement and positioning

During the construction of the silo, the positions of the reserved holes for the corbels are determined according to the design of the trusses and corbels, and the positions are accurately positioned to ensure that the lifting points of the trusses coincide with the positions of the corbels.

(5) Installation of spreaders and corbels

Use the external scaffolding built during the construction of the shallow round silo gutter as the operating platform, install hoisting hoist spreaders and supporting hoisting hoist connection cables and the main control box on the top of the silo wall, and use the outer scaffolding and the hanger under the steel truss to hang on the silo wall Reserve a place to install the corbel. The installation of clamps, spreaders and corbels is shown in Figure 4, Figure 5 and Figure 6. In Fig. 4, the fixture clamps the silo wall 6 from both sides through the channel steel 7, and several fixture bolts 9 are provided on one side of the fixture, and a reserved lifting hole 8 is provided. In Fig. 6, the steel plate of the corbel passes through the silo wall 6 from the inside of the silo to the outside of the silo through high-strength bolts 10 and is then tightened and fixed, so that the corbel is fixed on the silo wall inside the silo to withstand the force transmitted from above.

(6), truss lifting

The hoist is used to install the hoist on the spreader to lift the truss synchronously as a whole. The whole truss is initially synchronously lifted by 2 meters, and the whole ring operation hanger, protective net and bottom net are installed on the lower chord of the truss. Continue to raise the steel truss to the design elevation, and use the operating platform under the truss to install the supporting truss corbel. The steel truss and the corbel are connected and fixed, and the hoisting of the truss is completed. Then install the support frame and formwork on the truss to tie the steel bars and pour the concrete.

(7) Steel truss removal

After the concrete reaches the design strength, the trusses are removed. As shown in Figures 7 and 8, when dismantling, a reserved hole 14 is provided between the silo roof 15 and the silo wall 6, and the top of the silo wall 6 and the top of the silo roof 15 are respectively fixed with expansion screws. A 500×500, 12 thick fixed steel plate 12, and then use a 12# I-shaped steel 13 to connect the two fixed steel plates 12, a steel plate extending into the reserved hole 14 is provided under the I-shaped steel 13, the A hanging hole 11 is provided on the steel plate. Their positional relationship can be seen from the plan view shown in Figure 8. When dismantling, use the steel truss of the electric hoist. The steel hinge of each electric hoist passes through the lifting hole 11 of the silo roof 15, and is firmly connected with the steel structure frame to keep the balance of the steel structure frame. The truss is lowered to the bottom of the warehouse, and the entire sliding form platform is disassembled, cut and transported out of the door opening of the bottom of the warehouse by using tools such as welders and workers to operate wrenches.

Certainly, the above are only specific application examples of the present invention, and there are other implementation modes in the present invention, and all technical solutions formed by equivalent replacement or equivalent transformation all fall within the scope of protection required by the present invention.

Claims (6)

1. a kind of circular cone roofing integrally-lifting steel truss, it is characterised in that：It includes center disk（1）, center disk（1）'s Top is more than center disk provided with a collar plate shape superstructure, the diameter of the collar plate shape superstructure（1）Diameter, the collar plate shape superstructure The center of circle is in center disk（1）On projection and center disk（1）The center of circle overlap；Collar plate shape superstructure side semi-circular portions to Center disk（1）Extend some main rod hangers in the plane（2）, main rod hanger（2）With collar plate shape superstructure and center disk（1） The line in the center of circle be uniformly arranged in ring for axle；Collar plate shape superstructure opposite side semi-circular portions to center disk（1）Place Extend the main rod hanger of some and offside in plane（2）Corresponding upper cord member（3）；The main rod hanger（2）With top boom Part（3）In center disk（1）Tie point constitutes a complete big disk in the plane at place, and the diameter of the big disk is more than circle The diameter of dish-type superstructure；Above three disk and the main rod hanger for connecting them（2）, upper cord member（3）It is common with other connecting rods With the structure for constituting circular cone roofing integrally-lifting steel truss.

2. circular cone roofing integrally-lifting steel truss according to claim 1, it is characterised in that：Other connecting rods At least include being used to connect big disk and center disk（1）Lower edge rod member（4）, for connecting main rod hanger（2）And center disk （1）Pull bar（5）, for connecting center disk（1）With the diagonal brace hack lever of collar plate shape superstructure（16）.

3. a kind of construction of circular cone roofing integrally-lifting steel truss as claimed in claim 1, the engineering method is used for difference The roofing construction in diameter conical tube storehouse, it is characterised in that comprise the following steps：Truss Design and processing；Truss assembling；Truss First overall lifting 2m；Operation suspension bracket in truss bottom is installed；Truss is lifted；Bracket is installed and is connected firmly with truss；Set up purlin Frame upper support frame supporting plate, assembling reinforcement；Casting concrete；Drive and remove up to progress truss after 100% after concrete strength.

4. the construction of circular cone roofing integrally-lifting steel truss according to claim 3, it is characterised in that：Circle Cang Cang After the completion of tube construction, in storehouse, tube end plate assembles steel truss；Gutter template conduct is supported with the silo external scaffolding set up in advance Operating platform, lifting cucurbit steel structure suspender is installed on shallow cylinder bulkhead top, installs lifting electric block, and supporting lifting cucurbit Connecting cable and total control box；Truss is lifted to after designed elevation using electronic lifting cucurbit, steel truss is connected with bracket Fixed, truss lifting is completed；Complete concreting to reach after design strength, steel structure truss dismounting electric block, electronic calabash The steel hinge of reed both passes through silo roof roof boarding preformed hole, and the balance of steel construction support body is connected firmly and kept with steel construction support body, Steel truss is drop to manual demolition after silo base surface.

5. the construction of circular cone roofing integrally-lifting steel truss according to claim 3, it is characterised in that truss group Carried out as follows during dress：Steel truss transports to job site after machining, and is rechecked, numbered, using tower crane by truss Loose mail hangs in conical silo inner bottom plating, is installed in the following order：Reinforce hack lever → body frame bar（2）→ diagonal brace hack lever （16）→ center disk（1）→ pull bar（5）.

6. the construction of circular cone roofing integrally-lifting steel truss according to claim 3, it is characterised in that install ox Leg is simultaneously carried out when being connected firmly with truss as follows：The external scaffolding set up when being constructed using silo gutter operates flat Platform, installs lifting cucurbit suspender and supporting lifting cucurbit connecting cable and total control box on silo wall top, utilizes external scaffolding Bracket is installed in bulkhead reserved location with suspension bracket below steel truss.