Wind-resistant suspension bridge

A wind-resistant suspension bridge includes a bridge tower, a bridge body, a main rope, a suspension rope and a guardrail. The suspension bridge further includes a wind-resistant rope, one end of which is connected to the bridge tower and the other end of which is connected to the main rope. The wind-resistant rope, the main rope and the bridge tower form a substantially triangle. The contact point between the bridge tower and the main rope, the connection point between the wind-resistant rope and the main rope, and the connection point between the wind-resistant rope and the bridge tower form the three vertices of the substantially triangle.

TECHNICAL FIELD

The present application relates to the technical field of suspension bridge, and particularly relates to a wind-resistant suspension bridge.

DESCRIPTION OF RELATED ART

A bridge is a structure that allows pedestrians and vehicles to pass safely above the water surface. Therefore, when designing, it not only responds to the loads of people and vehicles, but also responds to external forces in the nature such as strong winds and earthquakes. Generally speaking, for suspension bridges, as the span increases, the amplitude of the swing also becomes larger, and the consideration of wind becomes more important.

Bridges mainly include beam bridges, arch bridges, rope-stayed bridges, suspension bridges, etc. Among these bridges, suspension bridges have many advantages compared with other bridges, such as a large span (up to nearly2kilometers), light weight, and economical material, short construction period, cost saving, good earthquake resistance, etc.

The suspension bridge suspends the entire bridge body through a suspension rope system. The bridge body in the main span length direction between the bridge towers is suspended in the air and has a long length, so the middle section of the bridge body has the poorest stability. The middle section of the bridge body is the middle part of the main span of the suspension bridge in the length direction. When strong winds are blowing, the suspension bridge is prone to undulating shake along the bridge axis direction and swing along the direction of the flowing water (perpendicular to the bridge axis). And, as the span of the bridge continues to increase, the flexibility of the bridge continues to increase, and the amplitude of the swing increases, making it more sensitive to wind excitation. Therefore, the impact of wind on the suspension bridge cannot be ignored.

How to reduce the shaking of the suspension bridge and enhance the wind resistance of the suspension bridge has always been a problem in the world of bridges.

SUMMARY

In order to improve the above-mentioned technical problem that the suspension bridge in the prior art is easy to shake, and to enhance the wind resistance of the suspension bridge, the present application provides a wind-resistant suspension bridge. The wind-resistant suspension bridge provided by the present application adopts the following technical solutions.

According to the object of the present invention, there is provided a wind-resistant suspension bridge, including a bridge tower, a bridge body, a main rope, a suspension rope and a guardrail. The suspension bridge further includes a wind-resistant rope, one end of which is connected to the bridge tower and the other end of which is connected to the main rope; the wind-resistant rope, the main rope and the bridge tower form a substantially triangle, the contact point between the bridge tower and the main rope, the connection point between the wind-resistant rope and the main rope, and the connection point between the wind-resistant rope and the bridge tower form the three vertices of the substantially triangle.

Preferably, one end of the wind-resistant rope is connected to the bridge tower through a damper, and the other end of the wind-resistant rope is connected to the main rope through a saddle clamp.

Preferably, the suspension bridge further includes an auxiliary rope provided above the main rope, and the auxiliary rope passes through the top of the bridge tower and both ends thereof are respectively anchored on the shore; the saddle clamp includes a main ring part for surrounding and clamping the main rope, an auxiliary ring part provided above the main ring part for surrounding and grasping the auxiliary rope, and a connecting part provided below the main ring part for connecting the suspension rope or for connecting both the suspension rope and the wind-resistant rope, and the main ring part and the auxiliary ring part are formed as a whole.

Preferably, the main ring part includes two first half rings with a semicircular cross section, and a horizontal first through hole is provided below the main ring part to make the two half rings of the main ring part connected together by a bolt and a nut provided in the through hole so as to form a complete ring and clamp the main rope;

the auxiliary ring part includes two second half rings with a semicircular cross section, and a horizontal second through hole is provided below the auxiliary ring part and above the main ring part to make the two half rings of the auxiliary ring part connected together by a bolt and a nut provided in the through hole so as to form a complete ring and grasp the auxiliary rope;

the saddle clamp further includes a cushion sleeve sleeved on the auxiliary rope and a tightening pipe tightening the auxiliary rope, one end surface of the cushion sleeve abuts against one end surface of the auxiliary ring part, and the other end surface of the cushion sleeve abuts against one end surface of the tightening pipe; for the saddle clamp where the connecting part only connects the suspension rope, the cushion sleeve and the tightening pipe are provided only at an end of the auxiliary ring part away from the bridge tower; for the saddle clamp where the connecting part connects both the suspension rope and the wind-resistant rope, the cushion sleeve and the tightening pipe are provided at both ends of the auxiliary ring part.

Preferably, the wind-resistant rope includes a long rope and a short rope, and each of the bridge tower is connected with two short ropes and one long rope,

two short ropes are provided symmetrically in the length direction of the bridge with respect to the bridge tower, and the short ropes are connected at a position of the bridge tower at the same horizontal plane as the bridge deck, the long rope is connected to the root of the bridge tower, the projections of the connection points between the long rope and the short rope and the main rope on the bridge deck divide the length of the bridge body from the bridge tower to the main span length direction centerline roughly into three equal parts.

Preferably, the suspension bridge includes a counterweight device that can adjust the position of a counterweight block along the bridge length direction and the vertical direction, and the counterweight device includes a rail, a horizontal drive mechanism, the counterweight block and a counterweight suspension frame,the rail extending along the bridge length direction is fixedly provided below the bridge body,the horizontal drive mechanism includes a winch, a fixed pulley and a traction rope symmetrically provided with respect to the main span length direction centerline; the winch is fixed at the bridge tower at one end of the rail below the bridge body on the side facing the river bank, and the fixed pulley is fixed at the other end of the rail at a position of the main span length direction centerline, the traction rope is connected to the winch and surrounds the fixed pulley so as to drive the counterweight suspension frame connected with the traction rope to move along the rail,the counterweight suspension frame is movably suspended on the rail along the bridge length direction; the counterweight block is provided on the counterweight suspension frame so as to be located at the lower portion of the counterweight device; the counterweight suspension frame further includes a hydraulic device so as to adjust the position of the counterweight block vertically with the help of the hydraulic device.

Preferably, the suspension bridge further includes a hanger rod provided in the middle section of the bridge body and fixed integral with the bridge body, the upper end of the hanger rod extends upwards from the bridge deck over the height of the guardrail and is connected to the lower end of the suspension rope, and the lower end of the hanger rod extends downwards from the bridge deck, penetrates the bridge body and is connected to the bottom of the bridge body.

Preferably, the suspension bridge further includes a first set of diagonal struts extending upwards obliquely from the bridge deck towards the hanger rod to be connected with the hanger rod, and the vertical plane on which the first set of diagonal struts is located extends along the bridge length direction and is located on the side of the hanger rod away from main span length direction centerline.

Preferably, the suspension bridge further includes a support plate extending outwards horizontally from the bridge deck along the bridge width direction, a second set of diagonal struts and a third set of diagonal struts, the second set of diagonal struts extends upwards obliquely from the support plate toward the hanger rod to be connected with the hanger rod; the third set of diagonal struts extends downwards obliquely from the support plate toward the bridge body to be connected with the bridge body, and the second set of diagonal struts and the third set of diagonal struts are located outside the guardrail.

Preferably, the suspension bridge further includes an upper slope provided at the edge of the bridge deck outside the guardrail along the bridge width direction, and a lower slope provided at the bottom edge of the bridge body along the bridge width direction,

the upper slope extends downwards obliquely from the edge of the bridge deck in the bridge width direction away from the bridge body, and when it extends to about two-fifths of the thickness of the bridge body from top to bottom, it extends downwards obliquely toward the bridge body to the bottom of the bridge body, thereby forming a harp corner at both ends of the cross section of the bridge body.

By adopting the above technical solutions, various measures have been taken in the main span of the suspension bridge to enhance the stability of the suspension bridge.

DESCRIPTION OF THE EMBODIMENTS

In order to make the purpose, technical solution and advantages of the present application embodiment clearer, the technical solution in the present application embodiment will be clearly and completely described below in conjunction with the drawings in the present application embodiment. Obviously, the described embodiments are part of the present application, rather than all of the embodiments. Based on the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

FIG.1shows an existing traditional suspension bridge1, which mainly includes a bridge tower2, a main rope4, a bridge body3, a guardrail6, etc. Four bridge towers2are symmetrically arranged relative to a main span length direction centerline28and a width direction centerline respectively. The main rope4is provided above the bridge body3. The main rope4is connected to the bridge body3with suspension ropes5. The main rope4passes through the top of the bridge tower2along the bridge length direction, and two ends of the main rope4are anchored at anchorages on the shore, so that the bridge body3can be suspended from the main rope4by the suspension rope5. Since the bridge body3, especially the middle section of the main span portion of the bridge body3, is suspended in the air, in case of strong winds, the suspension bridge1is prone to undulating shaking along the main span length direction or swing shaking along the width direction.

Referring toFIG.2, for a traditional suspension bridge1, the solid line represents the main rope4in a state without wind, and the dashed line represents the main rope4in a shaking state due to a strong wind. As shown in the drawing, when the air pressure above the bridge body3on the left side of the suspension bridge1is lower than the air pressure below the bridge body3, the part of the main rope4on the left side of the main span length direction centerline28is shaken upwards (as shown by the dashed double-dotted line), and the right part is shaken downwards (as shown by the dashed double-dotted line); when the air pressure above the bridge body3on the right side of suspension bridge1is lower than the air pressure below the bridge body3, the part of the main rope4on the right side of the main span length direction centerline28is shaken upwards (as shown by the short dashed line), and the left part is shaken downwards (as shown by the short dashed line). In the above two cases, the main rope4undulates between two contact points with the bridge tower2.

In order to improve wind resistance, the present application provides a suspension bridge1as described below.

A wind-resistant rope7includes a long rope71and a short rope72. Two short ropes72and one long rope71are provided respectively for each bridge tower2. Therefore, the suspension bridge1according to the present application includes eight short ropes72and four long ropes71.

One end of the long rope71is connected to the bridge tower2via a damper8. The damper8is provided at the root of the bridge tower2to act as cushioning when the wind-resistant rope7is subjected to a greater tension, which also makes the main rope4has a certain degree of freedom (the main rope4can be shaken within a certain swing amplitude), thereby improving the stability of the main rope4. The other end of the long rope71is connected to the main rope4of the main span of the suspension bridge via a saddle clamp9provided, which will be described in detail later.

One end of the short rope72is also connected to the bridge tower2via a damper8. The damper8connected to the short rope72is provided at a position of the bridge tower2at the same level as the bridge deck56. The other end of the short rope72is also connected to the main rope4via a saddle clamp9provided. For each bridge tower2, the corresponding two short ropes72are symmetrically arranged with respect to the bridge tower2in the bridge length direction.

In this case, as shown inFIGS.3and4, in the length range of the bridge body3from the bridge tower2to the main span length direction centerline28, projections of connection points, at which the long rope71and the short rope72are connected to the main rope4, on the bridge deck56divide this part of the bridge body3roughly into three equal parts.

The long rope71or the short rope72respectively form a substantially triangle with the bridge tower2and the main rope4to enhance stability. Therefore, By means of the wind-resistant ropes7, in case of a strong wind, the wave undulating and other shaking of the main rope4can be restricted, thereby improving the wind resistance of the suspension bridge1. Specifically, as shown inFIG.4, point A, point B, and the connection point at which the short rope72is connected to the bridge tower2substantially form a triangle; similarly, point A, point C, and the connection point at which the long rope71is connected to the bridge tower2substantially form a triangle. Similarly, point A′, point B′, and the connection point at which the short rope72is connected to the bridge tower2substantially form a triangle; point A′, point C′, and the connection point at which the long rope71is connected to the bridge tower2substantially form a triangle. Therefore, after the wind-resistant ropes7are provided on the suspension bridge1, the main rope4of the main span has a total of six connection points A, B, C, A′, B′, and C′ for controlling its shaking. Comparing with the prior art, the main rope4only has two points A and A′. Therefore, by providing the wind-resistant ropes7, wave undulating and other shaking of the bridge body3along the bridge length direction can be effectively avoided.

Referring toFIGS.5A-5C and5E, an auxiliary rope10and saddle clamps9are shown. The auxiliary rope10is provided above the main rope4, also passes through the top of the bridge tower2, and both ends thereof are respectively anchored on the shore. A conventional saddle clamp9or lock clamp used for the main rope4of the suspension bridge1mainly includes a main ring part11surrounding and clamping on the main rope4. Compared to the conventional saddle clamp9or lock clamp, the saddle clamp9in this embodiment includes an auxiliary ring part12provided above the main ring part11, which is formed integrally with the main ring part11. The auxiliary ring part12surrounds and clamps the auxiliary rope10. In addition, a connecting part13is provided below the main ring part11for connecting the suspension rope5(as shown inFIG.5C) or for connecting both of the suspension rope5and the wind-resistant rope7(as shown inFIG.5B).

The main ring part11includes two half rings14with a semicircular cross section, and horizontal through holes15are provided at the lower part of the main ring part11. The two half rings of the main ring part11are connected together by bolts and nuts provided in the through holes so as to form a complete ring and clamp the main rope4.

The auxiliary ring part12includes two half rings16with a semicircular cross section, and horizontal through holes17are provided at the lower part of the auxiliary ring part12and at the upper part of the main ring part11. The two half rings of the auxiliary ring part12are connected together by bolts and nuts provided in the through holes so as to form a complete ring and clamp the auxiliary rope10.

The saddle clamp9further includes a cushion sleeve18sleeved on the auxiliary rope10and a tightening pipe19tightening the auxiliary rope10. One end surface of the cushion sleeve18abuts against one end surface of the auxiliary ring part12, and the other end surface of the cushion sleeve18abuts against one end surface of the tightening pipe19, as shown inFIGS.5A-5C. For the saddle clamp9of which the connecting part13only connects to the suspension rope5, the cushion sleeve18and the tightening pipe19are provided only at an end away from the bridge tower2, so as to prevent the saddle clamp9from sliding towards the main span length direction centerline28. For the saddle clamp9of which the connecting part13connects to both the suspension rope5and the wind-resistant ropes7, the cushion sleeve18and the tightening pipe19are provided at both ends thereof, so as to prevent the saddle clamp9connected with the wind-resistant ropes7from sliding towards the bridge tower2. Preferably, the saddle clamp9is connected to the wind-resistant rope7via pin holes and pins.

The saddle clamp9clamps the main rope4and the auxiliary rope10, so that the wind-resistant rope7is fixedly connected to the main rope4, thereby enhancing the stability of the suspension bridge1in the case of strong winds.

As shown inFIG.6, in the present application, counterweight devices20are provided below the bridge body3of the suspension bridge1, which can adjust the positions of counterweight blocks23along the main span length direction and the vertical direction. A counterweight device20includes a counterweight block23, a rail21, a horizontal drive mechanism22, and a counterweight suspension frame24that adjusts the position of the counterweight block23in the vertical direction, and so on.

The rail21extends along the main span length direction and is fixedly arranged below the bridge body3. The rail21includes two load-bearing rails32that are arranged in parallel in the same horizontal plane and one guide rail33. The guide rail33is equidistantly arranged between the two load-bearing rails32, as shown inFIGS.7A and7D.

The horizontal drive mechanism22includes winches25, fixed pulleys26and traction ropes27etc., which are respectively symmetrically arranged with respect to the main span length direction centerline28. The winch25is fixed to one end of the rail21underneath the bridge body3at one side facing the river bank of the bridge tower2. The fixed pulley26is fixed to the other end of the rail21at the main span length direction centerline28. The traction rope27is connected to the winch25and surrounds the fixed pulley26so as to drive the counterweight suspension frame24connected with the traction rope27to move along the rail21, as shown inFIG.6andFIG.7A.

The counterweight suspension frame24is movably suspended on the rail21along the main span length direction. The counterweight block23is fixed in the counterweight suspension frame24so as to be located at the lower portion of the counterweight device20. The lower portion of the counterweight suspension frame24is provided with a hydraulic device29, so that the position of the counterweight block23can be adjusted vertically by the hydraulic device29. Specifically, the counterweight suspension frame24includes a rectangular truss30at the upper portion, as shown inFIG.7A. Two first rollers31are arranged vertically on each corner of the truss30, as shown inFIG.7B. By means of the two first rollers31vertically arranged, each corner is movably connected to the load-bearing rail32. A guide rail33is located on an axis of the main span length direction at the bottom of the bridge body3. Along the bridge width direction, at the position corresponding to the guide rail33, two second rollers34are horizontally arranged on the truss30between the two corners for guiding the movement of truss30, as shown inFIG.7C. With the above structure, the counterweight suspension frame24can move horizontally along the main span length direction below the bridge body3. Without wind or with small wind, the counterweight suspension frame24can be moved to be placed at the lower portion of the bridge tower2. With strong wind, the counterweight suspension frame24can be moved to a proper position in the middle section of the main span of the suspension bridge, and fixed to the proper position by a locking device (not shown) provided on the load-bearing rail32.

The counterweight suspension frame24further includes a fixed frame35and a counterweight vertical adjustment mechanism that are provided below the truss30. As shown inFIG.7A, the fixed frame35includes two suspension frame main pipes37that are obliquely arranged relative to the vertical direction. The counterweight vertical adjustment mechanism is arranged on the fixed frame35. The counterweight block23is fixed on the counterweight vertical adjustment mechanism. As shown inFIG.7A, the counterweight vertical adjustment mechanism preferably includes a hydraulic device29installed at the lower portion of the counterweight suspension frame24, and specifically includes a sliding guide rod38, an oil motor39, an oil tank40, an oil cylinder41, a piston42, a piston rod43, and an upper positioning plate44and a lower positioning plate45for the sliding guide rod, an oil cylinder41, a sliding upper plate46and a lower plate47, etc. When the oil motor39operates, with pushing the piston42by the oil, the oil motor39, the counterweight block23, the oil tank (pool)40, and the oil cylinder41move up and down along the two sliding guide rods38. In this way, the height of the center of gravity of the counterweight suspension frame24can be adjusted, that is, the swing frequency of the pendulum is changed by adjusting the length of the swing arm. Since the suspension frame is fixed with the bridge body3as a whole, by adjusting the swing (vibration) frequency of the bridge body3, the periodic vibration of the bridge body3due to external forces such as vortex vibration can be disturbed, thereby avoiding resonating of the bridge body3due to external forces.

The parameters such as weight, size, quantity, etc., of the counterweight suspension frame24can be determined according to the actual situation of the suspension bridge1. Generally, each counterweight suspension frame24weighs about 1 to 4 tons, and the number is 6 to 12. A plurality of counterweight suspension frames24are connected together at equal intervals along the main span length direction. The plurality of counterweight suspension frames24are located in the middle section of the main span of the suspension bridge along the main span length direction.

The above configuration ensures that the height of the center of gravity of the counterweight suspension frame24can be adjusted within a certain range in the vertical direction, so that the vibration frequency of the bridge body3can be adjusted at any time.

The operating process of the counterweight suspension frame24is as follows, seeFIGS.6and7A:(1) without wind or with a small wind, the counterweight suspension frame24is placed below the bridge tower2(a unloading device is required).(2) with a strong wind, the winch25pulls the suspension frame along the rail21with the ropes and the fixed pulley26to a suitable position in the middle section of the main span of the suspension bridge and locks the suspension frame along the rail21. At this time, heavy vehicles are forbidden to pass the bridge, and surface ships are reminded to avoid the counterweight suspension frame24.(3) with a very strong wind, all vehicles are forbidden to pass the bridge deck56, and preferably, large boats in the waterway are forbidden to pass the bridge at the same time.(4) the heights of the center of gravity of the counterweight blocks23of the counterweight suspension frames24are different to avoid resonance at the same time.

4. Hanger Rod Assembly

Referring toFIGS.8-9, a hanger rod assembly is shown. Each suspension rope5is connected to the bridge body3via a hanger rod assembly. The hanger rod assembly includes a hanger rod48, diagonal struts and support plate52etc., which are arranged in the middle section of the main span of the bridge and fixed integrally with the bridge body3. The hanger rod48is located outside the guardrail6. The range of the bridge deck56where the hanger rod48is provided is located in the middle section of the main span and occupies about one-fifth of the length of the main span of the suspension bridge. An upper end of the hanger rod48extends upwards from the bridge deck56over the height of the guardrail6and is connected to the lower end of the suspension rope5, and the lower end of the hanger rod48extends downwards from the bridge deck56to penetrate the bridge body3and is fixed to the bottom of the bridge body3. As shown inFIG.8, the hanger rod assembly includes a first set of diagonal struts49. The first set of diagonal struts49includes two diagonal struts that extend upwards obliquely from the bridge deck56towards the hanger rod48to connect to the hanger rod48. A vertical plane on which the first set of diagonal struts49is located extends along the main span length direction and is located on the side of the hanger rod48away from the main span length direction centerline28. In addition, as shown inFIG.9, the hanger rod assembly includes a support plate52extending outwards horizontally from the bridge deck56along the bridge width direction, a second set of diagonal struts50and a third set of diagonal struts51. The second set of diagonal struts50includes three diagonal struts extending upwards obliquely from the support plate52toward the hanger rod48to connect to the hanger rod48. The third set of diagonal struts51also includes three diagonal struts extending downwards obliquely from the support plate52toward the bridge body3to connect to the bottom of the bridge body3. The second set of diagonal struts50and the third set of diagonal struts51are located outside the guardrail6.

In this example, the hanger rod48is fixed to the bridge body3, and the lifting point57of the suspension rope5is at the top of the hanger rod48, so that the vertical distance between the center of gravity of the bridge body3and the lifting point57has increased a lot, compared with the traditional suspension bridge1, because the traditional lifting point57is located on the bridge deck56. The greater the vertical distance between the lifting point57and the center of gravity of the suspension bridge1, the more stable and balanced the suspension bridge1, and the less likely to vibrate and tilt or flip.

5. Wind Breaker and Tail Wing

An upper slope53is provided at the edge of the bridge deck56outside the guardrail6along the bridge width direction, and a lower slope54is provided at the bottom edge of the bridge body3along the bridge width direction, so that the cross section of the bridge body3of the suspension bridge1is generally streamlined.

As shown inFIG.10, the upper slope53extends downwards obliquely from the edge of the bridge deck56away from the bridge body3, and when it extends to about two-fifths of the thickness of the bridge body3from top to bottom, it extends downwards obliquely toward the bridge body3to the bottom of the bridge body3, thereby forming a harp corner55at both ends of the cross section of the bridge body3, thereby reducing the resistance of the bridge body3to the wind, as shown inFIGS.10to12. The position of the apex of the harp corner55is determined by wind tunnel tests. The harp corner55forms a wind breaker when facing the direction of wind blowing, while the harp corner55forms a tail wing when facing away from the direction of wind blowing, so that the cross section of the bridge body3is generally streamlined. This streamlined structure greatly reduces the transverse impact force of the windward side of the bridge body3from the wind, and the vortex generated after the wind blows through the bridge body3can also be effectively reduced.

In summary, by providing the suspension bridge1with the above measures (especially the wind-resistant rope7and the counterweight device20), the wind resistance of suspension bridge1is greatly improved, thus increasing safety. The utilization rate of the suspension bridge1will also be increased, and the service life is prolonged.

LIST OF REFERENCE SIGNS