CN117552311A

CN117552311A - Combined stressed bridge with inflatable membrane body and bridge deck plate bottom coupled

Info

Publication number: CN117552311A
Application number: CN202210928741.0A
Authority: CN
Inventors: 张立乾; 闫晶; 陈红; 李兵; 孟良; 吴星; 王卉; 李泽; 王永强; 贾佳
Original assignee: 63921 Troops of PLA
Current assignee: 63921 Troops of PLA
Priority date: 2022-08-03
Filing date: 2022-08-03
Publication date: 2024-02-13

Abstract

The invention discloses a combined stressed bridge with an inflatable membrane body and a bridge deck plate bottom coupled, which belongs to the technical field of bridge structure design, and comprises a bridge deck bearing plate and an inflatable mould body; the inflatable mould body is a closed mould body with a geometric shape, the top of the inflatable mould body is coupled with the bottom surface of the bridge deck bearing plate, and medium-low pressure inflation is carried out in the inflatable mould body, and the internal pressure is 60 kPa-100 kPa. The inflatable membrane body is used as a sealing membrane of the inflatable membrane and is equivalent to a tensioning dense cable coupled with the membrane body, the expansion and tensioning of the membrane body are realized through the inflation deformation of the membrane body, the upper support of a bridge deck bearing plate is realized, and meanwhile, the automatic inflation function is matched in the pressurizing and inflating process, so that the erection time can be greatly shortened, and the rapid assembly of a bridge is realized.

Description

Combined stressed bridge with inflatable membrane body and bridge deck plate bottom coupled

Technical Field

The invention belongs to the technical field of bridge structure design, and particularly relates to a combined stressed bridge with an inflatable membrane body and a bridge deck bearing plate bottom coupled.

Background

The bridge equipment is an important engineering guarantee device for realizing rapid maneuver along with task actions, in particular to crossing obstacles such as canyons, ditches and the like in the strong river. The traditional bridge equipment has the problems of large weight, large volume, low erection speed, low bearing capacity, more security personnel, more transportation vehicles and the like, and the maneuvering performance of the equipment is seriously affected. The development of a novel bridge device with light weight, quick erection, strong bearing capacity and high maneuverability has important practical significance.

The inflatable structure has a unique advantage and is focused in the wide engineering field, and the inflatable structure has a wide application prospect in the fields of aerospace, near-space vehicles and large-scale buildings. The inflatable structure is a special structural form, and compressed air is utilized to form the inflatable fabric into a predetermined shape and achieve a predetermined function. Compared with the traditional steel structure and aluminum structure, the inflatable structure has the characteristics of light weight, small storage and transportation volume, high erection speed and high structural damping. With the development of related industrial technologies of the inflatable structure, particularly the appearance of high-performance fibers and fabrics, conditions are created for the further development of the inflatable structure.

The inflatable structure causes the film to generate tensile stress through the internal pressure of the air bag and causes the structure to reach considerable rigidity, thereby causing the structure to have strength and rigidity resisting external load. The bearing capacity of the air bag depends on the magnitude of the internal pressure, and the improvement of the internal pressure of the air bag can improve the bearing capacity of the structure to a certain extent, but the large breakthrough cannot be realized, and the film is subjected to excessive stress due to excessive internal pressure, so that the safety problem is easily caused. Therefore, to fully exploit the advantages of the inflatable structure in reducing its limitations, it is necessary to develop a combined version of the inflatable structure and other rigid structures.

Disclosure of Invention

In view of the above, the invention provides a combined stressed bridge with an inflatable membrane body and a bridge deck plate bottom, the inflatable membrane body is used as a sealing membrane of the inflatable membrane and is equivalent to a tensioning dense cable coupled with the membrane body, the inflation and tensioning of the membrane body are realized through the inflation deformation of the membrane body, the support of a bridge deck bearing plate is realized, and meanwhile, an automatic inflation function is matched in the pressurizing and inflating process, so that the erection time is greatly shortened, and the rapid assembly of the bridge is realized.

A combined stressed bridge with an inflatable membrane body and a bridge deck plate bottom coupled comprises a bridge deck bearing plate and an inflatable mould body;

the inflatable die body is a closed die body with a geometric shape, the top of the inflatable die body is coupled with the bottom surface of the bridge deck bearing plate, medium-low pressure inflation is carried out in the inflatable die body, and the internal pressure is 60 kPa-100 kPa.

Further, the edge to the bottom of the inflatable die body is in arc transition.

Further, the mid-span sagittal height of the inflatable membrane takes 1/15 to 1/4 of the span of the bridge deck bearing plate.

Further, the inflatable membrane body is formed by overlapping three layers of a closed inner container, a stress layer and an outer sleeve, and the closed inner container is made of high-toughness rubber materials; the stress layer is made of carbon fiber, polyester fiber or a high-strength steel wire material compounded outside the rubber layer; the material of the outer sleeve is canvas; the thickness of the three layers is between 3mm and 6 mm.

Further, the cross section of the bridge deck bearing plate adopts a triangular multi-cavity truss type, namely a sandwich plate structure type formed by an upper panel, a lower panel and a middle triangular diagonal brace, the diagonal brace included angle is 60 degrees, the total thickness of the aluminum alloy bridge deck bearing plate is 150mm, and the upper panel, the lower panel, the diagonal brace plate and the vertical supporting plate at the end part are all 5mm.

Further, the length of the inflatable membrane body is smaller than the length of the bridge deck bearing plate, and the width of the inflatable mould body is equal to the width of the bridge deck bearing plate.

Further, the inflatable membrane body is structurally divided into a top membrane and a bottom membrane, the top surface of the top membrane is adhered to the bottom surface of the bridge deck bearing plate, the top membrane and the bottom membrane are clamped through steel clamping plates after being overlapped in a certain width of the edge, vertical stress is applied to the membrane body after being overlapped through high-strength bolts by the steel clamping plates, meanwhile, the steel clamping plates penetrate through the bridge deck bearing plate through the high-strength bolts to be fixed, the bridge deck bearing plate and the inflatable membrane body are combined and fixed, lining membranes are arranged in the joint of the top membrane and the bottom membrane, the lining membranes are continuously distributed around the top membrane on a plane, and the lining membranes are adhered to the top membrane and the bottom membrane through high-strength colloid.

The beneficial effects are that:

1. the invention combines the inflatable membrane body and the bridge deck bearing plate based on the stress principle of the inflatable membrane, the top of the inflatable membrane body is directly connected with the bridge deck bearing plate, the membrane body is used as a sealing membrane of the inflatable membrane and is equivalent to a tensioning dense cable coupled with the membrane body, the inflation and tensioning of the membrane body are realized through the inflation deformation of the membrane body, the upper support of the bridge deck bearing plate is realized, the quality of the full bridge can be controlled within 1700kg, the pressurization and inflation process is matched with an automatic inflation function, and the erection time can be greatly shortened, thereby realizing the rapid assembly of the bridge.

2. The edge to bottom of the inflatable die body is in arc transition, so that when the internal pressure of the inflatable die body is between 60 and 100kPa, the inflatable die body generates optimal matching of the jacking force of the bridge deck bearing plate and the internal pressure when expanding.

3. The inflatable membrane body is formed by overlapping three layers of a closed inner container, a stress layer and an outer sleeve, wherein the closed inner container mainly provides a closed airtight environment; the stress layer is made of high tensile strength material, and can be made of carbon fiber, polyester fiber or composite high-strength steel wire outside the rubber layer; the outer cover is made of canvas materials, and can provide necessary friction resistance and abrasion resistance for the surface.

4. The numerical calculation of the combined stressed bridge proves that the requirements of strength and rigidity can be met, the stress of the inflatable membrane body can be controlled within 250MPa, the deflection of live load is controlled within 1/200 of the span, and meanwhile, the bridge deck bearing plate can meet the overall and local stability.

5. The bottom film of the inflatable film body in the bridge deck bearing plate coupling stress mechanism can be equivalent to a flexible dense cable similar to a string beam, the gas in the film body can be equivalent to a supporting rod, and the bridge deck bearing plate can be equivalent to a rigid upper chord, so that a bidirectional self-balancing structure system is formed, the rise of the middle of the inflatable film body is 1/15-1/4 of the span of the bridge deck bearing plate, and the coupling stress of the film body and the bridge deck bearing plate can achieve the optimal effect.

6. The inflatable membrane is formed by combining the top membrane and the bottom membrane which are relatively independent, a lining membrane is arranged in the joint of the top membrane and the bottom membrane, the lining membrane is continuously distributed along the periphery of the top membrane on a plane, and the lining membrane is bonded with the top membrane and the bottom membrane by adopting high-strength colloid, so that the membrane stress of the joint of the top membrane and the bottom membrane can be improved; meanwhile, a closed space between the top film and the bottom film can be formed, so that air leakage is prevented, and the service time and the service life of the inflatable die body are prolonged.

Drawings

FIG. 1 is a schematic elevation view of a combined stressed bridge with the inflatable membrane coupled to the deck slab bottom of the present invention;

FIG. 2 is a schematic cross-sectional view of a composite stressed bridge with the inflatable membrane coupled to the deck slab floor of the present invention;

FIG. 3 is a schematic elevational view of the inflatable membrane of the present invention;

FIG. 4 is a schematic cross-sectional view of the inflatable membrane of the present invention;

FIG. 5 is an enlarged view of a portion of FIG. 1 at A;

FIG. 6 is a partial enlarged view at B in FIG. 2;

FIG. 7 is a schematic view of a partial structure of a deck load bearing plate;

FIG. 8 is a three-dimensional schematic view of a computational model (obliquely upward looking);

FIG. 9 is a schematic diagram of an equivalent force transfer mechanism of the midsole of an inflatable mold body;

FIG. 10 is a cross-sectional view of an inflatable mold body in three selected line shapes;

FIG. 11 is a view of three selected linear longitudinal sections of the profile of an inflatable mold body;

wherein, 1-bridge deck loading board, 2-inflatable membrane body, 2-1-basement membrane, 2-2-top film, 2-3-lining film, 3-steel splint, 4-high strength bolt.

Detailed Description

The invention will now be described in detail by way of example with reference to the accompanying drawings.

As shown in fig. 1 and 2, the invention provides a combined stressed bridge with an inflatable membrane body and a bridge deck plate bottom, wherein the combined stressed bridge comprises a bridge deck bearing plate 1 and an inflatable mould body 2.

The inflatable die body 2 is a closed die body with a geometric shape, the edge of the inflatable die body 2 in the embodiment is in arc transition from the bottom to the bottom, the top of the inflatable die body 2 is coupled with the bottom surface of the bridge deck bearing plate, medium-low pressure inflation is carried out in the inflatable die body 2, and the internal pressure is 60 kPa-100 kPa.

As shown in fig. 3 and 4, the inflatable membrane is structurally divided into a top membrane 2-2 and a bottom membrane 2-1; as shown in figures 5 and 6, the top surface of the top film 2-2 is adhered to the bottom surface of the bridge deck bearing plate 1, the top film 2-2 and the bottom film 2-1 are clamped by the steel clamping plates 3 after being overlapped within a certain width at the edge, the steel clamping plates 3 apply vertical stress to the overlapped film body by the high-strength bolts 4 so as to realize the combination fixation of the top film 2-2 and the bottom die 2-1, meanwhile, the steel clamping plates 3 penetrate through the bridge deck bearing plate 1 by the high-strength bolts 4 so as to realize the combination fixation of the bridge deck bearing plate 1 and the inflatable film body 2, the lining film 2-3 is arranged in the combination position of the top film and the bottom film, the lining film 2-3 is continuously distributed on the plane along the periphery of the top film, and the lining film 2-3 is adhered by adopting the high-strength colloid and the top film 2-2 and the bottom film 2-1.

The material of the inflatable membrane in the embodiment is composed of a closed inner container, a stress layer and an outer sleeve which are overlapped, wherein the closed inner container mainly provides a closed airtight environment and is composed of a high-toughness rubber material; the stress layer is made of high tensile strength material, and can be made of carbon fiber, polyester fiber or composite high-strength steel wire outside the rubber layer; the outer cover mainly provides necessary friction and abrasion resistance on the surface and can be made of canvas and other materials. The thickness of the three layers is between 3mm and 6 mm.

The bottom film in the coupling stress mechanism of the inflatable film body 2 and the bridge deck bearing plate 1 can be equivalent to a flexible dense cable in a similar string beam, the gas in the film body can be equivalent to a supporting rod, the bridge deck bearing plate can be equivalent to a rigid upper string, and the two-way self-balancing structural system is provided, and the equivalent force transmission mechanism of the film body is shown in figure 7.

The bridge deck carrier plate 1 in this embodiment adopts aluminum alloy bridge deck carrier plate, and bridge deck carrier plate 1 cross-section adopts triangle multicavity truss type, and the sandwich plate structural style that upper and lower panel adds middle triangle bracing constitution promptly, and the bracing contained angle is 60, and aluminum alloy bridge deck carrier plate total thickness is 150mm, and upper and lower panel and bracing board and tip vertical support board are 5mm, and the partial schematic diagram is shown in fig. 8.

The membrane body and the bridge deck bearing plate are required to have a certain sagittal height from the angle of coupling stress, and generally 1/15-1/4 of the span of the bridge deck bearing plate can be taken; from the simple membrane stress angle, the stress of the whole flow line without any angle is optimal. The linear shape of the cross section of the inflatable membrane base membrane is selected from circular arc, parabola or combination of straight line and circular arc or parabola, as shown in figure 9.

The two ends of the linear form of the vertical section of the inflatable mould body are formed by the curve sections at the two ends and the straight line section in the middle, and the two ends are formed by the rotation and sweep of the cross section linear form around the central axis, so that the joint of the end part and the middle part is completely tangent, and the full-film full-flow line is realized, and the linear form of the end part and the transverse linear form are consistent, as shown in figure 10.

And (3) bridge bearing performance analysis:

the physical and mechanical parameters of the calculation model are shown in table 1, and the three-dimensional representation of the whole calculation model is shown in figure 11.

TABLE 1 physical and mechanical index Table

Model name	Density of	Modulus of elasticity	Poisson's ratio	Thickness of structure	Remarks
						Inflatable membrane	1.0	4E4	0.32	3	Internal pressure of
Bridge deck bearing plate	2.7	7.0E4	0.33	5

Modeling amount: the numerical calculation object is an arc shell which spans an 8m bridge and has the bridge deck width of 3.673m, and the initial state of the inflatable membrane body is 500mm in height.

Splitting units: the inflatable membrane body adopts a three-dimensional membrane unit, the bridge deck bearing plate adopts a shell unit, the size of the inflatable membrane unit is 50mm multiplied by 50mm, and the size of the bridge deck bearing plate unit is 50mm multiplied by 50mm.

Material constitutive relation: elastic mechanism is adopted.

Interaction: the contact area between the top periphery of the inflatable membrane and the bottom of the bridge deck bearing plate is in binding connection.

Boundary conditions: the width of 50mm at the end part of the bridge deck bearing plate is simply supported constraint.

Load step division: the method comprises the steps of 4, wherein the first load step is to inflate an inflatable membrane, the inflation is divided into multiple stages of loading, the maximum load step length is 0.01, and the inflation is finally loaded to the internal pressure of 80 kPa; the second loading step is the structure gravity field loading, and is divided into 1 loading step loading; the third loading step is the load loading of the level II lane of the road with the least favorable quarter span, and is divided into uniform load and concentrated load, wherein the value of the uniform load is 10.5kPa, the uniform load is distributed on the top surface of the bridge deck bearing plate, the concentrated force of the concentrated load is 276kN, the concentrated force is uniformly distributed on 2 areas of 0.2m multiplied by 0.6m, and the corresponding load concentration is 1150kN/m ² Maximum load step size 0.1; the fourth loading step is loading of the load of the class II lane of the least favorable road in the midspan, and the maximum load step length is 0.1. When the fourth load step is applied, the concentrated load of the third load step fails.

Load effect under the first load step:

when the inflation internal pressure is loaded to 80kPa, the film body is vertically expanded by 6.4 percent, namely 32mm, from the integral structure vertical displacement cloud picture, and the expansion rate of the film body is much smaller than that of the film body in the combination II, because the film body configuration in the combination II is closer to the inflation tightening state, and the bridge deck bearing plate generates a pre-camber of 31 mm. The maximum stress of the membrane Msies stress cloud chart after the inflation loading is 211.9MPa, the membrane Msies stress cloud chart is positioned at the root part of the middle part of the membrane and connected with the bridge floor, and the membrane stress of other areas is between 70MPa and 80MPa of the membrane except the area, and is within the allowable stress range of the membrane. The Msies stress cloud chart of the bridge deck bearing plate shows that the maximum stress is 147.3MPa, and the peak stress appears in the middle areas of the bottom plate and the top plate of the bridge deck, which is identical to the stress mechanism of the bridge deck bearing plate, namely the bottom of the bridge deck bearing plate bears the action of the air pressure of the film body and the periphery of the plate is fixedly connected with the film body, which is equivalent to the bidirectional stress plate under the action of upward uniformly distributed load of the bridge deck bearing plate.

Load effect under the action of the second load step:

the second loading step is to apply a gravitational field, which is about 59kg/m because the structure itself is very light in weight ² The gravitational field effect is small. Compared with the first loading step, the central area of the bridge deck bearing plate is lowered by 1.1mm from the vertical displacement cloud chart of the integral structure, and the extreme stress is equivalent to that of the first loading step from the Msies stress cloud chart of the second loading step.

Load effect under the action of the third load step:

the third load step is to apply lane load, uniformly distribute load to act on the whole span and concentrate load to act on one quarter of the span. The cloud display of the structural vertical displacement diagram shows that the maximum forward vertical displacement of the center of the bridge deck bearing plate is reduced to 1.9mm from 29.9mm of the last load step, and the difference value between the maximum forward vertical displacement and the last load step is the deflection under the action of live load, namely 28mm, and is 1/286 of the span, so that the requirement is met; the Msies stress cloud chart of the film body shows that the extreme stress is equivalent to that of the first loading step and the second loading step; the Msies stress cloud chart of the bridge deck bearing plate shows that the maximum stress is 154.3MPa, and the maximum stress is increased by 4.8% compared with the first load step.

Load effect under the action of the fourth load step:

and the fourth load step is to apply lane load, uniformly distribute load to act on the whole span and concentrate load to act on the middle span. The cloud of the structural vertical displacement diagram shows that the maximum forward vertical displacement of the center of the bridge deck bearing plate is reduced to-6.4 mm from 29.9mm of the second load step, and the difference value between the maximum forward vertical displacement and the second load step is the deflection under the action of live load, namely 36.3mm, which is 1/220 of the span, so that the requirement is met; the Msies stress cloud chart of the film body shows that the extreme stress is equivalent to that of the first loading step, the second loading step and the third loading step; the Msies stress cloud of the bridge deck bearing plate shows that the maximum stress is 156.7MPa, which is equivalent to the third loading step.

Structural stability analysis:

the film body structure and the bridge deck bearing plate joint part of the centralized load in the lane load are extracted from the film body internal force when the centralized load is positioned in the midspan, and the film body internal force and the film body internal pressure are applied to the outer boundary of the film body top surface and the film body top surface together. And taking the uniformly distributed load and the concentrated load of the lane as external loads for structural stability analysis, keeping boundary constraint conditions at two ends of a bridge deck bearing plate unchanged, examining the buckling stability characteristic value of the structure, and taking the first 10-order mode. The position, form and characteristic values of the front 10-order buckling mode of the bridge deck bearing plate are shown in table 2. According to the equivalent membrane loading schematic diagram, the front four-stage buckling modes are the plate bottom of the midspan region and the bulging instability of the support plate, which are related to the fact that the region is under the concentrated load of the lane and the stress is large, the minimum buckling characteristic value is 2.81, and the structure is proved to have certain safety reserve; as shown in Table 2, the ten-stage buckling instability positions are all in the midspan region, the midspan center is alternately changed to the two sides of the midspan, the buckling characteristics are improved from 2.81 to 5.80, and the buckling characteristics are unstable due to buckling of the plate bottom and the supporting plate.

Table 2 bridge deck load bearing plate buckling mode table

Step(s)	Unsteady position	Morphology of the product	Special buckling tool
				A first part	Center of midspan	Board bottom and diagonal bracing	2.81
Two (II)	Near the bottom of the mid-span plate	Board bottom and diagonal bracing	3.13
				Three kinds of	Near the bottom of the mid-span plate	Board bottom and diagonal bracing	3.88
Fourth, fourth	Near the bottom of the mid-span plate	Board bottom and diagonal bracing	4.44
				Five kinds of	Near the bottom of the mid-span plate	Board bottom and diagonal bracing	4.61
Six kinds of	Near the bottom of the mid-span plate	Board bottom and diagonal bracing	5.00
				Seven pieces of	Middle left Bian Ceban	Board bottom and diagonal bracing	5.51
Eight (eight)	Middle right side plate	Board bottom and diagonal bracing	5.58
				Nine pieces	Middle left Bian Ceban	Board bottom and diagonal bracing	5.73
Ten times	Middle left Bian Ceban	Board bottom and diagonal bracing	5.80

Numerical calculation proves that the top of the membrane body in the structure system is directly connected with the bridge deck bearing plate, the membrane body is used as a sealing membrane of an inflatable membrane and is equivalent to a tensioning dense cable coupled with the membrane body, and the expansion and tensioning of the membrane body are realized through the inflation deformation of the membrane body, so that the upper support of the bridge deck bearing plate is realized. The tensile strength of the existing high-strength membrane material can reach more than 500MPa, the maximum stress of the membrane material analyzed by the method is within 250MPa and is far lower than the strength limit value, if a carbon fiber material is adopted, the tensile strength of the membrane material can reach more than 2000MPa and far exceeds the peak stress in the calculation example, so that the existing high-strength fiber material provides a wide application space for a high-strength membrane body. Full bridge mass energy in calculation exampleThe pressure and inflation process can be matched with an automatic inflation function within 1700kg, so that the erection time is greatly shortened, and the possibility of realizing rapid assembly of the bridge is provided.

In summary, the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The combined stressed bridge with the coupled inflatable membrane body and the bridge deck plate bottom is characterized by comprising a bridge deck bearing plate and an inflatable mould body;

2. The composite stressed bridge of claim 1, wherein said inflatable membrane is in a rounded transition from edge to bottom.

3. The composite stressed bridge of claim 2, wherein said inflatable membrane is mid-span with a sagittal elevation of 1/15-1/4 of the span of the deck carrier.

4. The combined stressed bridge with the coupling of the inflatable membrane body and the bridge deck slab bottom according to claim 2, wherein the inflatable membrane body is formed by overlapping three layers of a closed inner container, a stressed layer and an outer sleeve, and the closed inner container is made of a high-toughness rubber material; the stress layer is made of carbon fiber, polyester fiber or a high-strength steel wire material compounded outside the rubber layer; the material of the outer sleeve is canvas; the thickness of the three layers is between 3mm and 6 mm.

5. The composite stressed bridge with the inflatable membrane coupled with the bottom of the bridge deck plate as claimed in claim 4, wherein the cross section of the bridge deck bearing plate adopts a triangular multi-cavity truss type, namely a sandwich plate structure type formed by an upper panel, a lower panel and a middle triangular diagonal brace, the diagonal brace included angle is 60 degrees, the total thickness of the aluminum alloy bridge deck bearing plate is 150mm, and the upper panel, the lower panel, the diagonal brace plate and the end vertical supporting plate are 5mm.

6. The composite stressed bridge of claim 5, wherein the length of the inflatable membrane is less than the length of the deck load-bearing plate, and the width of the inflatable membrane is equal to the width of the deck load-bearing plate.

7. The combined stressed bridge of claim 5 or 6, wherein the inflatable membrane body is structurally divided into a top membrane and a bottom membrane, the top surface of the top membrane is adhered to the bottom surface of the bridge deck bearing plate, the top membrane and the bottom membrane are clamped by a steel clamping plate after being overlapped within a certain width at the edge, the steel clamping plate applies vertical stress to the overlapped membrane body through a high-strength bolt so as to realize the combined fixation of the top membrane and the bottom mould, and meanwhile, the steel clamping plate penetrates through the bridge deck bearing plate through the high-strength bolt so as to realize the combined fixation of the bridge deck bearing plate and the inflatable membrane body, a lining membrane is arranged in the joint of the top membrane and the bottom membrane, the lining membrane is continuously distributed around the top membrane on a plane, and the lining membrane is adhered by adopting the high-strength colloid, the top membrane and the bottom membrane.