Background
With the continuous promotion of the infrastructure construction process of China, people realize that the convenience degree of urban internal traffic and urban inter-traffic greatly influences the national economic development and social progress; therefore, the country has realized the big development of road, bridge engineering in recent decades. The bridge structure is not only widely applied to urban overpasses, subway light rails, high-speed railways and the like, but also widely applied to river-crossing and sea-crossing structures. In recent years, with the construction of ultra-large bridge projects such as the mao bridge in hong kong zhu and the mao bridge in hangzhou bay, bridge structures at home and abroad face unprecedented opportunities for development. In the construction of bridge structures, the bridge deck plate not only plays a role in bearing loads such as the dead weight of an upper structure and passing vehicles, but also faces long-term effects such as wheel friction, driving vibration, water and ion erosion, and the like, so that higher requirements are put forward on the bearing capacity, durability and toughness of the bridge deck plate.
The reinforced concrete bridge deck is widely applied in actual engineering, but cannot be applied to bridge structures with large span due to the fact that the self weight of concrete is large and the tensile property of concrete materials is poor. In order to solve the problem, orthotropic steel bridge deck slabs are produced at the same time; the orthotropic bridge deck system formed by arranging longitudinal and transverse stiffening ribs outside the steel bridge deck can obviously improve the bearing efficiency of the bridge deck and the economic span of the structure; however, considering that steel materials are easy to rust when exposed to air for a long time, the durability of the orthotropic bridge deck becomes a problem to be solved urgently in engineering.
In order to solve the problems, a combined bridge deck system is formed by combining steel and concrete materials in engineering, so that the tensile property of the steel and the compressive property of the concrete are fully exerted, and the bearing performance of the structure is further improved. However, the existing steel-concrete composite bridge deck still has some problems: firstly, in order to ensure sufficient shear connection between steel and concrete and prevent the separation of the interface between the steel and the concrete, more studs (playing the double roles of shear resistance and pulling resistance) are usually arranged between the steel and the concrete, so that the construction workload is greatly increased, and the fatigue performance of the structure is influenced due to the existence of welding seams; secondly, the steel deck sections in the composite deck slab usually require a plurality of stiffening ribs to be welded out of plane, which also increases the amount of construction and affects the fatigue performance of the structure; thirdly, the common concrete material is easy to crack after being tensioned and is sensitive to local defects, cracks are easy to generate under the action of long-term load, water and ions are corroded, the corrosion resistance and durability of the bridge deck are affected, the maintenance cost of the bridge structure is obviously increased, and huge waste is caused to manpower and material resources.
Disclosure of Invention
In order to solve the problems of the traditional steel-concrete combined bridge deck slab system, the invention provides a non-stud toughness combined bridge deck slab system.
A studless flexible composite decking system, comprising:
a plurality of L shape turn-up shaped steel that place side by side along the bridge floor is vertical in succession, L shape turn-up shaped steel include: the L-shaped structure is formed by the bottom plate and the flange plates, one end of the L-shaped structure where the bottom plate is located is curled to form a connecting end, and one end of the L-shaped structure where the flange plates are located is curled to form a reinforcing end;
reinforcing steel bars penetrating through the L-shaped curled profile steels;
and concrete poured on a bridge deck steel framework formed by the L-shaped curled steel sections and the steel bars.
In the invention, the L-shaped curled profile steels are continuously arranged side by side along the longitudinal direction of the bridge deck, and the adjacent profile steels are welded through two fillet welds to form a bridge deck steel framework. A row of round holes are formed in the L-shaped rolled-edge steel flange plate, and the longitudinal steel bars penetrate through the L-shaped rolled-edge steel flange plates through the round holes. The ultra-high toughness concrete is poured on the bridge deck steel skeleton to play a role in protecting the bridge deck steel skeleton. In the combined bridge deck slab system provided by the invention, the ultra-high-toughness concrete can ensure that no or only micro cracks below 100 micrometers are generated under the action of various loads, and the toughness and durability of the structure are improved; the structural mode that L shape turn-up shaped steel and longitudinal reinforcement combine together plays effectual shear and resistance to plucking effect, has replaced the effect of peg and horizontal reinforcing bar, therefore greatly reduced material cost and construction complexity, and fatigue property is superior.
The following are preferred technical schemes of the invention:
the connecting end of the L-shaped structure curled edge is arranged in parallel with the flange plate. And each L-shaped curled profile steel is welded and connected with the connecting end of the next L-shaped curled profile steel in sequence through the flange plate of the previous L-shaped curled profile steel.
The reinforcing end of the L-shaped structure curled edge is formed by curling the edge in a direction parallel to the bottom plate firstly and then curling the edge in a direction parallel to the flange plate secondly.
The L-shaped rolled section steel is provided with a row of round holes, and the steel bars penetrate through the round holes in the L-shaped rolled section steel. The reinforcing steel bars are longitudinally arranged along the bridge deck. Namely, the steel bars longitudinally pass through round holes on the L-shaped curled profile steels along the bridge deck.
The concrete is ultra-high toughness concrete, and the thickness of the ultra-high toughness concrete layer is slightly higher than the height of the bridge deck steel skeleton, so that the effect of protecting the bridge deck steel skeleton is achieved.
In the non-stud toughness combined bridge deck slab system, L-shaped rolled-edge section steel is continuously placed side by side along the longitudinal direction of a bridge deck, and adjacent section steel is welded through two fillet welds to form a bridge deck steel framework.
In the non-stud toughness combined bridge deck slab system, a row of round holes are formed in the L-shaped rolled-edge type steel flange plates, and the longitudinal steel bars penetrate through the L-shaped rolled-edge type steel flange plates through the round holes.
In the non-stud toughness combined bridge deck slab system, ultra-high toughness concrete is poured on a bridge deck steel framework; the thickness of the ultra-high toughness concrete layer is slightly higher than the height of the bridge deck steel framework, and the ultra-high toughness concrete layer plays a role in protecting the bridge deck steel framework. The thickness of the ultra-high toughness concrete layer is 10-30% higher than the height of the bridge deck steel framework.
The ultra-high toughness concrete adopted by the invention comprises cement, an active mineral admixture, aggregate, reinforcing fiber and water, wherein the cement and the active mineral admixture are prepared from the following raw materials in percentage by weight:
most preferably, the ultra-high toughness concrete adopts the following raw materials by weight percent:
the invention provides a non-stud toughness combined bridge deck system, which is formed by combining a steel skeleton formed by welding cold-formed steel, longitudinal steel bars and ultra-high toughness concrete, and has the following advantages:
(1) the adopted ultra-high-toughness concrete has high bearing capacity under compression, shows strain hardening characteristics under tension, can stably reach more than 3 percent under the limit tensile strain, only has a plurality of densely distributed fine cracks under the limit tensile strain, can effectively separate steel from the external environment, prevents the steel from being corroded, and improves the toughness, the corrosion resistance and the durability of a bridge deck structure.
(2) The bridge deck steel skeleton is formed by welding L-shaped curled profile steel, the processing process is simple and efficient, and the bridge deck steel skeleton can be combined with an industrial welding robot, so that the processing process is industrialized; the bridge deck parameters can be flexibly changed by changing the size of the section steel, so that the modularization degree of a bridge deck system is improved while design and construction are facilitated.
(3) The shear connection effect between the steel skeleton and the ultra-high toughness concrete is ensured by utilizing the structural mode of combining the section steel flange and the longitudinally-passing steel bar; the flange structure at the upper end of the flange is further combined to play a role in resisting pulling, so that the separation of the steel and concrete interface is prevented; the system avoids the use of studs, obviously reduces the construction complexity and the cost, and simultaneously obviously improves the fatigue performance of the structure.
(4) The shaped steel flange has transversely played the effect of horizontal reinforcing bar at the bridge floor, therefore the use of horizontal reinforcing bar is avoided to the accessible appropriately adjustment shaped steel size, avoids ligature reinforcing bar net when reducing the steel quantity to show promotion efficiency of construction, reduce cost.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
As shown in fig. 1 and 2, a studless flexible composite bridge deck system comprises the following components: the steel comprises L-shaped curled steel 1, longitudinal steel bars 2 and ultra-high toughness concrete 4.
As shown in figure 3, L-shaped curled steel sections 1 are continuously arranged side by side along the longitudinal direction of the bridge deck, and adjacent steel sections 1 are welded through two fillet welds 3 to form a bridge deck steel framework, wherein 5 is the longitudinal direction of the bridge deck.
As shown in fig. 4, a row of round holes are formed on the flange plates of the L-shaped rolled section steel 1, and the longitudinal steel bar 2 passes through each flange plate of the L-shaped rolled section steel 1 through the round holes.
As shown in fig. 1 and 2, the ultra-high toughness concrete 4 is poured on the bridge deck steel framework; the thickness of the ultra-high toughness concrete 4 is slightly higher than the height of the bridge deck steel framework, and the ultra-high toughness concrete plays a role in protecting the bridge deck steel framework.
The ultra-high toughness concrete comprises the following components of cement, an active mineral admixture, aggregate, fiber and water, wherein the active mineral admixture comprises fly ash, silica fume, granulated blast furnace slag and metakaolin, the maximum particle size of the aggregate is not more than 0.5mm, the fiber adopts one or the combination of more than one of polyvinyl alcohol fiber, polyethylene fiber and aromatic polyamide fiber, the fiber length is 5-25 mm, the diameter is 0.015-0.055 mm, the elastic modulus is 30-150 GPa, the tensile strength is 1000-3500 MPa, the ultimate elongation is 2-15%, and the weight ratio of the cement to the active mineral admixture is as follows:
the performance test of the ultra-high toughness concrete obtained under the mixing proportion shows that the ultimate tensile strain can reach 3.2 percent (about 320 times of the concrete), and the width of a corresponding crack is 0.049mm when the ultimate tensile strain is achieved; the flexural strength was 12.8MPa (about 2 times that of concrete), the uniaxial compressive strength was 48MPa, and the compressive strain corresponding to the peak load was 0.55% (about 2 times that of concrete).
The ultra-high toughness concrete adopted by the non-stud toughness combined bridge deck system provided by the invention can ensure that the non-stud toughness combined bridge deck system does not generate or only generates micro cracks below 100 micrometers under the actions of pulling, pressing, bending and other various loads, has the functions of cracking resistance, seepage prevention and corrosion resistance, and obviously improves the toughness and durability of the structure. The structural mode of combining the open-pore L-shaped curled edge steel bar with the longitudinal passing steel bar can play an effective role in shearing resistance and pulling resistance, thereby effectively replacing the function of the stud in a combined structure. Research shows that in the traditional steel-concrete combined bridge deck slab, if a complete shear connection effect needs to be realized, the number of the studs in each square meter of the bridge deck slab is different from 20 to 100, and the number of the studs is increased along with the increase of factors such as the thickness of a concrete layer, the strength of concrete, external load and the like; the invention can effectively eliminate the negative effects of the material cost, the construction cost and the welding of the studs on the fatigue performance. In addition, the invention effectively avoids the use requirement of the transverse steel bar, reduces the material cost and shortens the construction period. Therefore, the non-stud toughness combined bridge deck plate system provided by the invention can improve the toughness and durability of the structure, greatly reduce the material cost and the construction complexity, and has potential of popularization and application in bridge structures.