CN108252425A - A kind of steel tube confined concrete node structure and corresponding truss structure and construction method - Google Patents

Abstract

The present invention relates to a kind of steel tube confined concrete node structures, including chord member and web member, the chord member includes steel pipe and bar frame with web member, one end of the bar frame is embedded in through normal concrete in steel pipe, the other end extends outside steel pipe, it is connected with each other between the chord member and web member through external bar frame, junction has poured ultra-high performance concrete, it is simple in structure, with bearing capacity height, construct the advantages of relatively simple, and overcome concrete-filled steel tube truss node mutually the place of passing through because adjacent steel-pipe welding cause steel pipe tired the shortcomings that.

Description

A steel pipe confined concrete joint structure and corresponding truss structure and construction method

technical field

The invention relates to a steel pipe restrained concrete node structure, a corresponding truss structure and a construction method.

Background technique

Concrete filled steel pipe refers to a component formed by filling concrete in steel pipes. Usually, steel pipes and the core concrete inside bear external loads together, which can make up for the shortcomings of steel pipes and concrete when they are used alone. Concrete-filled steel tubes are often used in long-span space structures and bridges in the form of trusses. As a concrete-filled steel tube truss system, common forms include flat or spatial K, T, X, Y, and N-type concrete-filled steel tube nodes. K-type nodes are the most common. At the nodes of the concrete-filled steel tube truss structure, on the intersecting line connecting the branch and the main pipe, due to the sudden change in geometric shape, and the existence of welding defects and welding residual tensile stress between adjacent steel pipes at the node, near the intersecting line of the tube node High stress concentration often occurs, which is easy to cause the occurrence and development of fatigue cracks, and reduces the resistance of the pipe joints and the entire truss structure to alternating loads. Under daily fatigue loads, the joints of concrete-filled steel tube trusses are prone to cracking. Fatigue cracks originate from the initial defects in the high-stress area. Near the "hot spot", the surface cracks propagate and penetrate the pipe wall, and gradually expand to destroy the joints, resulting in the failure of the entire truss. loss of structural capacity.

Contents of the invention

In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a steel pipe confined concrete joint structure and corresponding truss structure and construction method, which are not only simple in structure, but also convenient and efficient.

In order to solve the above-mentioned technical problems, the technical solution of the present invention is: a steel pipe-constrained concrete node structure, including a chord and a web, the chord and the web both include a steel pipe and a steel grid, and one end of the steel grid They are pre-embedded in steel pipes with ordinary concrete, and the other ends extend out of the steel pipes. The chords and webs are connected to each other through external steel grid frames, and ultra-high performance concrete is poured at the joints.

Preferably, each of the steel grid frames includes several longitudinal reinforcements, and several longitudinal reinforcements are bound together through several stirrups; wherein the length of the longitudinal reinforcement embedded in the steel pipe of the chord is 2-3 times that of the steel pipe of the chord The diameter of the concrete section and the length of the longitudinal reinforcement protruding out of the steel pipe are the length of the joint supervisor; the length of the longitudinal reinforcement embedded in the steel pipe of the web is 2-3 times the diameter of the concrete section inside the steel pipe of the web and the length of the longitudinal reinforcement protruding out of the steel pipe The length is the length of the branch pipe of the node; the anchorage length of the longitudinal reinforcement of the web member on the longitudinal reinforcement of the chord is not less than 12 times the diameter of the longitudinal reinforcement of the web member.

Preferably, the number of the chord and the web is two, and the two chords are located on the straight line where the node main pipe is located, and the two webs are located on the oblique line where the node branch is located, and the chord and the reinforced grid outside the web Interconnected and poured with ultra-high-performance concrete into an inverted "K"-shaped node structure.

A corresponding truss structure of steel pipe confined concrete, including several inverted "K" shaped steel pipe confined concrete node structures, wherein the chords of the left and right adjacent steel pipe confined concrete node structures are connected in a straight line, and the upper and lower adjacent The webs of the steel tube confined concrete node structure are connected in an oblique shape to form a truss structure with upper and lower chords parallel to each other and several wavy webs between the upper and lower chords.

Preferably, the steel pipes of the chords of the left and right adjacent steel pipe-constrained concrete node structures are made into one, and are shared by adjacent chords; The abdominal rod is shared.

A construction method of a steel pipe-constrained concrete node structure, which is carried out in the following steps: (1) the chord and web parts are transported to the construction site after pouring; (2) through the "K"-shaped UHPC cast-in-place node mold, the The chords and webs are fixed at the corresponding positions in the mold, and UHPC is poured into the mold through the pouring hole of the mold; (3) After 28 days of normal temperature curing, the mold is removed to form a UHPC cast-in-place steel pipe confined concrete node.

Preferably, in step (1), when the chord and the web are made, the longitudinal reinforcement is bound and fixed with stirrups, and the binding position is placed in the steel pipe at 1/3-1/2 of the mouth of the steel pipe. Ordinary concrete is poured in the steel pipe, and the formwork is removed after solidification, and then cured at room temperature for 28 days. The length of the longitudinal reinforcement embedded in the steel pipe of the chord is 2-3 times the diameter of the concrete section inside the steel pipe of the chord, and the longitudinal reinforcement protruding out of the steel pipe The length is the length of the main pipe of the node; the length of the longitudinal reinforcement embedded in the steel pipe of the web is 2-3 times the diameter of the concrete section inside the steel pipe of the web, and the length of the longitudinal reinforcement protruding out of the steel pipe is the length of the branch pipe of the node. The anchorage length on the longitudinal reinforcement of the chord is not less than 12 times the diameter of the longitudinal reinforcement of the web.

Preferably, in step (2), the mold is composed of a "K"-shaped left half steel mold and a "K"-shaped right half steel mold, and the left half steel mold and the right half steel mold are connected by bolts Screwed together to form a hollow "K"-shaped mould, the periphery of the mold is provided with a pouring hole leading to the node, and the mold is provided with an exhaust through hole at the periphery of the steel mold forming the branch pipe of the node; The pipe length of the mold is greater than the length of the node main pipe and the node branch pipe.

Preferably, in step (2), for the convenience of demoulding, a layer of machine oil is applied inside the mold.

Compared with the prior art, the present invention has the following beneficial effects: (1) The bearing capacity is greatly improved, the plasticity is increased, and the mechanical properties are reliable. (2) The joints do not need to weld adjacent steel pipes on site, but to pour concrete connections to avoid the fatigue of steel pipes caused by welding at the joint intersections of steel pipe concrete trusses, resulting in cracks and affecting the mechanical performance of the joints.

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

Description of drawings

Figure 1 is a schematic diagram of the structure of a steel tube-confined concrete joint structure.

Fig. 2 is a schematic diagram of the structure of the corresponding truss structure of steel tube confined concrete.

Figure 3 is a schematic diagram of the structure of the chord.

Figure 4 is a schematic diagram of the structure of the web bar.

Fig. 5 is a structural schematic diagram of the left half steel mold.

Figure 6 is a schematic diagram of the structure of the mold.

Fig. 7 is a schematic diagram of the use state of the mold.

Detailed ways

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with reference to the accompanying drawings.

As shown in Fig. 1-7, a steel pipe confined concrete node structure includes a chord 1 and a web 2. Ordinary concrete 4 is pre-embedded in the steel pipe, and the other end extends out of the steel pipe. The chords and webs are connected to each other through an external steel grid frame, and ultra-high performance concrete 5 is poured at the connection.

In the embodiment of the present invention, the reinforced grid includes several longitudinal bars 6, and several longitudinal bars are bound together by several stirrups 7, and the joints are encrypted with longitudinal bars and stirrups to reduce the UHPC tensile cracks. Produced; the length of the longitudinal reinforcement embedded in the steel pipe of the chord is 2-3 times the diameter of the concrete section inside the steel pipe of the chord, and the length of the longitudinal reinforcement protruding out of the steel pipe is the length of the joint supervisor; The length of the longitudinal reinforcement is 2-3 times the diameter of the inner concrete section of the web steel pipe, and the length of the longitudinal reinforcement extending out of the steel pipe is the length of the node branch; the anchorage length of the longitudinal reinforcement of the web on the longitudinal reinforcement of the chord is not less than 12 times the diameter of the longitudinal rib of the rod.

In the embodiment of the present invention, the number of the chord and the web is two, and the two chords are located on the straight line where the main pipe of the node is located, and the two webs are located on the oblique line where the branch pipe of the node is located. The steel grid frames are connected to each other and poured into an inverted "K"-shaped node structure by ultra-high performance concrete.

A corresponding truss structure of steel pipe confined concrete, including several inverted "K" shaped steel pipe confined concrete node structures, wherein the chords of the left and right adjacent steel pipe confined concrete node structures are connected in a straight line, and the upper and lower adjacent The webs of the steel tube confined concrete node structure are connected in an oblique shape to form a truss structure with upper and lower chords parallel to each other and several wavy webs between the upper and lower chords.

In the embodiment of the present invention, the steel pipes of the chords of the left and right adjacent steel pipe-constrained concrete node structures are made into one, and are shared by adjacent chords; the steel pipes of the webs of the upper and lower adjacent steel pipe-constrained concrete node structures are made into one , shared by adjacent webs.

A construction method of a steel pipe-constrained concrete node structure, which is carried out in the following steps: (1) the chord and web parts are transported to the construction site after pouring is completed; (2) through the "K" shaped UHPC cast-in-place node mold 8, Fix the chords and webs at the corresponding positions in the mold, and pour UHPC into the mold through the pouring hole of the mold; (3) After the pouring is completed and the UHPC is solidified, after 28 days of curing at room temperature, the mold is removed to form a UHPC cast-in-place steel pipe Constrained concrete nodes.

In the embodiment of the present invention, in step (1), when the chord and the web are manufactured, the longitudinal reinforcement is bound and fixed with stirrups, and the binding position is at 1/3-1/2 of the steel pipe nozzle, placed Among the steel pipes, the longitudinal bars and stirrups are mainly used to strengthen the bond between the steel pipe-constrained concrete webs and chords and the cast-in-place UHPC joints; pour ordinary concrete in the steel pipes, remove the formwork after solidification, and perform 28-day room temperature curing. The length of the longitudinal reinforcement embedded in the steel pipe of the rod is 2-3 times the diameter of the concrete section inside the steel pipe of the chord, and the length of the longitudinal reinforcement extending out of the steel pipe is the length of the joint supervisor; the length of the longitudinal reinforcement embedded in the steel pipe of the web is 2 -3 times the diameter of the inner concrete section of the web steel pipe, the length of the longitudinal reinforcement protruding out of the steel pipe is the length of the node branch pipe, and the anchorage length of the longitudinal reinforcement of the web member on the longitudinal reinforcement of the chord is not less than 12 times the diameter of the longitudinal reinforcement of the web member times.

In the embodiment of the present invention, in step (2), the mold is prefabricated according to the shape and size of the intersection of steel tube-constrained concrete K-shaped joints. ”-shaped right half steel mold 10, the left half steel mold and the right half steel mold are screwed to each other through bolts 11, and combined into a hollow “K” shaped mold inside, and the periphery of the mold is provided with a The pouring hole 13 of the node is used for UHPC pouring, and the mold is provided with an exhaust through hole 12 on the steel mold periphery forming the node branch pipe, which is convenient for the gas in the mold to discharge when pouring UHPC, and the mold can be reused; the pipe of the mold The length is greater than the length of the node main pipe and the node branch pipe, which is convenient for fixing it on the chord and the web.

In the embodiment of the present invention, in step (2), a layer of machine oil is brushed inside the mold for easy demoulding.

The present invention is not limited to the above-mentioned optimal implementation mode, and anyone can obtain other various forms of steel pipe-confined concrete node structures and corresponding truss structures and construction methods under the inspiration of the present invention. All equivalent changes and modifications made according to the patent scope of the present invention shall fall within the scope of the present invention.

Claims (9)

1. a kind of steel tube confined concrete node structure, it is characterised in that：Including chord member and web member, the chord member is wrapped with web member Steel pipe and bar frame are included, one end of the bar frame is embedded in through normal concrete in steel pipe, the other end extends Outside steel pipe, it is connected with each other between the chord member and web member through external bar frame, junction has poured very-high performance coagulation Soil.

2. steel tube confined concrete node structure according to claim 1, it is characterised in that：The bar frame includes Several vertical muscle, several vertical muscle are integrated through several stirrup bindings；Pre-buried vertical muscle length is wherein in the steel pipe of chord member 2-3 times of chord member steel pipe inner concrete diameter of section, the vertical muscle length stretched out outside steel pipe are node host length；Wherein web member Pre-buried vertical muscle length is 2-3 times in steel pipe web member steel pipe inner concrete diameter of section, the vertical muscle length stretched out outside steel pipe are Node branch length of tube；Anchorage length of the vertical muscle of the web member on the vertical muscle of chord member is not less than the 12 of the vertical muscle diameter of web member Times.

3. steel tube confined concrete node structure according to claim 2, it is characterised in that：The number of the chord member and web member Amount is two, and two chord members are located at node host institute on straight line, where two web members are located at node branch pipe on oblique line, the chord member It is connected with each other with the bar frame outside web member and pours the node structure for " K " shape through ultra-high performance concrete.

4. a kind of corresponding truss structure of steel tube confined concrete, using steel tube confined concrete node as claimed in claim 3 Structure, it is characterised in that：The steel tube confined concrete node structure of " K " shape, the wherein adjacent steel pipe in left and right are fallen including several The linear being connected as one between the chord member of confined concrete node structure, neighbouring steel tube confined concrete node knot The oblique line shape being connected as one between the web member of structure, composition is with the top-bottom chord being mutually parallel and between top-bottom chord Several wavy web members truss structure.

5. the corresponding truss structure of steel tube confined concrete according to claim 4, it is characterised in that：The adjacent steel pipe in left and right The steel pipe manufacturing of the chord member of confined concrete node structure is integrated, and is shared for adjacent chord member；Neighbouring steel tube confinement The steel pipe manufacturing of the web member of concrete joint structure is integrated, and is shared for adjacent web member.

6. a kind of construction method of steel tube confined concrete node structure, which is characterized in that using as described in claim 1-3 Any steel tube confined concrete node structure, and carry out according to the following steps：（1）Chord member and web member part are after the completion of pouring It is transported to construction site；（2）By the UHPC cast-in-place node molds of " K " shape, chord member and web member are fixed on corresponding position in mold, UHPC is carried out by the pouring hole of mold toward mould inside to pour；（3）After room temperature conserves 28 days, mold is removed, is formed by Steel tube confined concrete node cast-in-place UHPC.

7. the construction method of steel tube confined concrete node structure according to claim 6, it is characterised in that：In step （1）In, when making, by vertical muscle stirrup banding fixed, the position of binding is in steel pipe nozzle 1/3-1/2 for chord member and web member Place, is positioned among steel pipe, and normal concrete is poured in steel pipe, and form removal after solidification carries out room temperature maintenance in 28 days, the steel of chord member Pre-buried vertical muscle length is 2-3 times in pipe chord member steel pipe inner concrete diameter of section, the vertical muscle length stretched out outside steel pipe are section Point supervisor's length；Web member steel pipe inner concrete diameter of section, stretching steel of the pre-buried vertical muscle length for 2-3 times in the steel pipe of web member Vertical muscle length outside pipe is node branch length of tube, and the anchorage length of the vertical muscle of web member on the vertical muscle of chord member is vertical not less than web member 12 times of muscle diameter.

8. the construction method of steel tube confined concrete node structure according to claim 6, it is characterised in that：In step （2）In, the mold is made of the left half of punching block of " K " shape and the right half of punching block of " K " shape, the left half of punching block and right half It is mutually spirally connected through bolt between the punching block of side, is combined into " K " shape mold of boring, the mold circumference, which offers, leads to node Pouring hole, the mold formed node branch pipe punching block circumference offer exhaust hole；The pipe range of the mold is all higher than The length of node host and node branch pipe.

9. the construction method of steel tube confined concrete node structure according to claim 6, it is characterised in that：In step （2）In, for convenience of demoulding, in mould inside brush last layer machine oil.