CN111254979B - A cable anchor system for an underwater cable-stayed suspension tunnel - Google Patents

Abstract

The invention discloses a cable anchor system for an underwater cable-stayed suspension tunnel, comprising four cable receiving wells, four groups of cable steering piers, cable ramps and multiple cables. Four cable receiving wells are respectively set on the shore side of the two sides of the tunnel and on the opposite bank side; each cable receiving well includes cable anchoring piers and monitoring room; four groups of cable steering piers are respectively located on the two sides of the tunnel. The bank slope of this side coast on the side and the bank slope of the opposite bank side are close to the four cable receiving wells in one-to-one correspondence; the cable ramps are located between each group of cable steering piers and the corresponding cable receiving wells. One end of the stay cable is anchored on both sides of the floating tunnel in the water, and the other end passes through the steering fairlead in the steering pier of the stay cable and extends to the ground along the underwater stay cable ramp, and then anchors On the cable anchor pier. The cable anchor system of the invention can be used for tunnel positioning when the tunnel pipe section is installed; during the tunnel operation period, it can also perform cable force monitoring and stay cable maintenance and replacement.

Description

A cable anchor system for an underwater cable-stayed suspension tunnel

technical field

The invention relates to an underwater suspension tunnel, in particular to a cable anchor system for an underwater cable-stayed suspension tunnel.

Background technique

Submerged Floating Tunnel, the English name is "Submerged Floating Tunnel", or "SFT" for short. In Italy, it is also known as "Archimedes Bridge", referred to as "PDA" bridge. Generally, it consists of a tubular body floating at a certain depth in the water (the tubular body has a large space enough to meet the requirements of road and railway traffic), a support system (anchor cables anchored on the seabed foundation, piers or floating boxes on water) and It is composed of structures on both sides of the strait. It is a new type of structure for transportation vehicles to cross between the two banks separated by deep water. It is suitable for all transportation vehicles that need to pass through water. It can pass trains, cars, small motor vehicles and pedestrians. It can also be used to pass through various Service channels for pipes and cables. The difference between a suspended tunnel in water and a traditional submerged tunnel or excavated tunnel is that the suspended tunnel structure is surrounded by water, neither on the stratum nor through the stratum, but mainly depends on the gravity of its own structure, the buoyancy of the structure and the support The anchoring force of the system to hold it in a fixed position. Suspended tunnels are sealed all around, this structure has all the characteristics of a normal tunnel and should be considered a "tunnel" rather than a "bridge" from a usage point of view.

Suspended tunnels can pass through different waters, such as rivers, fjords, straits, lakes, etc., and provide a possible and acceptable fixed spanning structure form for those places that are considered insurmountable due to the consideration of deep water or the distance between the two banks is too large. The suspension tunnel is built at a certain depth underwater. Compared with the open channel on the water surface and ferry transportation, severe wind and waves, fog, rain, snow and other weather will not affect the all-weather operation of the suspension tunnel. On the premise of ensuring the same navigable capacity, compared with bridges, the slope of suspension tunnels is gentler and the overall length is also reduced. The suspension tunnels will not have any impact on the environment and natural landscape during the construction process or when they are put into use; when the span exceeds a certain span When the water depth increases, the unit cost of the suspension tunnel will not increase significantly with the increase of the spanning channel length or the channel depth, while the unit cost of the cable-stayed bridge and the suspension bridge will increase significantly with the increase of the span.

Although suspended tunnels have certain advantages compared with immersed tunnels, deep buried tunnels, bridges and other cross-sea passage schemes, the design and construction of suspended tunnels are still a worldwide problem, and no suspended tunnels have been built yet. At present, there are 7 countries in the world (Norway, Italy, Japan, China, Switzerland, Brazil, and the United States). And the design of the landing structure, the feasibility of the tunnel structure, the construction and operation risks, etc. Whether these problems can be solved determines whether the suspension tunnel can move from a feasible solution to an actual project.

So far, in the study of suspended tunnels, according to the relationship between the gravity of the suspended tunnel itself and the buoyant force, the proposed structural types can be roughly divided into three categories: buoyant type, anchored type, and pier-column type. The buoy-type suspension tunnel is to suspend the tunnel on the buoy on the water surface through the anchor cable or anchor chain. The gravity of the tunnel is greater than the buoyancy, and the vertical direction is greatly affected by the fluctuation of the tide level. On the anchorage foundation below the bed, the gravity of the tunnel is less than the buoyancy, and the tunnel will be displaced or shaken under the action of hydrodynamics; the pier-column type is actually a tunnel bridge supported on underwater piers, which is difficult and expensive to construct. Since the tunnel floats in the water, the installation and construction of the tunnel is affected by wind, waves, currents and ships traveling waves. The three types of tunnels are difficult to locate underwater and connect underwater or above the water, and the comfort and safety during the underwater operation period are very difficult. Risks are difficult to predict.

In order to make the force of the suspension tunnel more reasonable, reduce the influence of the unfavorable sea conditions during the construction period, and be more conducive to the control during the construction period, the maintenance during the operation period and the replacement of parts, an underwater cable-stayed cable system suspension tunnel is proposed. Structure and construction method of jack-up installation of tunnel pipe sections. The underwater cable-stayed cable system suspension tunnel is composed of an underwater suspension tunnel 1, a shore connection structure 2, a cable-stayed anchor system, a floating-weight ratio adjustment system, an anti-collision warning system, an escape system, and tunnel auxiliary facilities. The underwater suspension tunnel 1 is connected to the shore connection structure 2, and is connected to the ground road through the land slope tunnel 6. The underwater suspension tunnel 1 is provided with stay cables 3 and fixed on the cable anchor piers 4 on the banks 5 on both sides of the tunnel to form a stable structure. the force system (see Figure 1). The construction method of pushing and installing the pipe sections of the cable-stayed suspension tunnel is as follows: after all the pipe sections are prefabricated in the prefabrication field behind the entrance (or exit) of the land area of the tunnel, they are transported to the shore connection structure 2 through the land area slope tunnel 6 for Docking section by section, outfitting for the second time, sealing into the water, and then pushing it into the landing structure 2 on the opposite bank one by one. After the jacking is completed, pour the concrete on the outer surface of the pipe section of the landing section in the landing structure 2 to complete the floating tunnel 1 in the water. Consolidation of the pipe joints of the landing section at both ends and the landing structure 2.

Therefore, it is necessary to propose a cable anchor system corresponding to the suspended tunnel structure and construction method of the underwater cable-stayed cable system.

SUMMARY OF THE INVENTION

The purpose of the present invention is to fill the gap of the prior art and provide a cable anchor system for an underwater cable-stayed suspension tunnel, which can be used for tunnel positioning when the tunnel pipe section is installed; Cable force monitoring and cable maintenance and replacement.

The purpose of the present invention is to achieve this: a cable anchor system for an underwater cable-stayed suspension tunnel, the underwater cable-stayed suspension tunnel includes a tunnel body, a pair of shore structures, a cable anchor system and a floating Gravity ratio adjustment system; the tunnel body includes a water suspension tunnel and a land slope tunnel;

The cable anchor system adopts bidirectional single cable plane or bidirectional double cable plane and includes four cable receiving wells, four groups of cable steering piers, cable ramps and multi-channel stay cables; wherein,

Four cable receiving wells are located on the shore on both sides of the tunnel and on the opposite bank on both sides of the tunnel in one-to-one correspondence; each cable receiving well includes cable anchoring piers and a monitoring room; The cable anchor pier is arranged at the lower part of the cable receiving well; the water-facing side of the cable anchor pier is provided with a fairlead; the middle part of the cable anchor pier is provided with a cable force monitoring slot, and the cable force monitoring slot is arranged in the cable force monitoring slot. Force monitor, the two ends of the cable force monitoring slot are anchor blocks; the rear end of the cable anchor pier is provided with an electric windlass; the monitoring room is set at the upper part of the cable receiving well, and the monitoring room is provided with a stay cable monitoring device;

Four groups of cable steering piers are located on the shore slope on both sides of the tunnel and on the opposite shore side of the tunnel in a one-to-one correspondence, and are close to the four cable receiving wells in a one-to-one correspondence; each group of cable steering The piers are located at the maximum depth of the channel; the number of cable steering piers in each group is half of the total number of stay cables; the bottom of each cable steering pier is higher than the elevation of the suspended tunnel in the water and not higher than the minimum bottom elevation of the channel ;In the interior of each stay cable steering pier, a cable channel is set along the direction of the stay cable, and a steering fairlead is pre-embedded on the cable channel;

The cable ramp is arranged on the bank slope between each group of cable steering piers and the corresponding cable receiving well;

Half of the multi-channel stay cable is the bank side stay cable, and the other half is the opposite bank side stay cable; For the stay cables connected to the two sides of the water suspension tunnel respectively; one end of the shore side stay cable is anchored at intervals on the stay cable anchors on the outer surfaces of both sides of the water suspension tunnel near the half length of the bank, and the bank side is inclined. The other end of the stay cable passes through the two sets of stay-cable steering piers on the bank, and then extends to the ground along the stay-cable ramp, and then anchors on the two stay-cable anchor piers on the bank. One end of the cable is anchored at intervals on the cable anchors on the outer surfaces of the two sides of the water suspension tunnel close to the opposite bank. The road is extended to the ground, and then anchored on the two cable anchor piers on the opposite bank.

In the above-mentioned cable anchor system for an underwater cable-stayed suspension tunnel, the cable anchor system further includes four power stations each provided on the land behind the four cable receiving wells.

In the above-mentioned cable anchor system of an underwater cable-stayed suspension tunnel, the cable anchor pier is a reinforced concrete pier structure with a pile foundation at the lower part.

In the above-mentioned cable anchor system of an underwater cable-stayed suspension tunnel, each cable steering pier is a reinforced concrete pier structure with a pile foundation at the bottom.

In the above-mentioned cable anchor system of an underwater cable-stayed suspension tunnel, the structure of the cable ramp is composed of riprap slope protection, crushed stone cushion and concrete surface layer in order from bottom to top.

In the above-mentioned cable anchor system of an underwater cable-stayed suspension tunnel, the cable-stayed cable adopts an ultra-high molecular weight polyethylene fiber cable, and the water-floating-to-weight ratio of the cable-stayed cable is 1.

The cable anchor system of the underwater cable-stayed suspension tunnel of the present invention has the following characteristics:

1) The underwater suspension tunnel cable anchor system of the present invention is suitable for the cable-stayed underwater suspension tunnel type, especially suitable for the cable-stayed suspension tunnel type using the jacking installation process.

2) The cable anchor system of the present invention can be used for tunnel positioning when the tunnel pipe section is installed; during the tunnel operation period, it can also perform cable force monitoring and cable maintenance and replacement.

3) The cable anchor system of the underwater suspension tunnel of the present invention extends the cable-stayed index to above the water surface, and the cable anchor pier is located in the cable monitoring room. Therefore, the installation of the suspension tunnel pipe joint is not restricted by the climatic and meteorological conditions of the open sea , greatly reducing the construction period.

4) The stay cable anchorage system of the underwater suspension tunnel of the present invention can adjust the length and tension of the stay cable correspondingly when adjusting the buoyancy-to-weight ratio of the suspension tunnel during the construction period and the operation period.

Description of drawings

Fig. 1 is the plan view of underwater cable-stayed suspension tunnel;

Fig. 2 is the structural representation of the cable anchor system of the underwater cable-stayed suspension tunnel of the present invention;

Fig. 3 is the structural representation of the cable receiving well in the cable anchor system of the underwater cable-stayed suspension tunnel of the present invention;

Fig. 4 is the structural representation of the cable anchor pier in the cable anchor system of the underwater cable-stayed suspension tunnel of the present invention;

5 is a schematic structural diagram of a cable steering pier in the cable anchor system of the underwater cable-stayed suspension tunnel of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

Please refer to FIG. 1 to FIG. 5 , the cable anchor system of the underwater cable-stayed suspension tunnel of the present invention is suitable for the underwater cable-stayed suspension tunnel. It is composed of float-weight ratio adjustment system, anti-collision warning system, escape system, tunnel auxiliary facilities, etc. The tunnel body includes an underwater suspension tunnel 1 and a land slope tunnel 6. The underwater suspension tunnel 1 is connected by prefabricated multi-section tunnel pipe joints;

The cable anchoring system of the present invention adopts two-way single cable plane or two-way double cable plane and includes four cable receiving wells 4, four power stations 7, four groups of cable steering piers 8, cable ramps 9 and multiple channels stay cable 3.

The four cable receiving wells 4 are located on the shore on both sides of the tunnel and on the opposite bank on both sides of the tunnel in one-to-one correspondence; each cable receiving well 4 includes a cable anchor pier 4A and a monitoring room 4B; ,

The cable anchor pier 4A is located at the lower part of the cable receiving well 4; the cable anchor pier 4A is a reinforced concrete pier structure with a pile foundation 40 at the lower part to increase the pullout resistance and ensure the stability of the bank slope; A fairlead 41 is provided on the waterside side of the pier 4A to turn the stay cable 3 in the horizontal direction; a cable force monitoring slot 42 is arranged in the middle of the cable anchor pier 4A, and a cable force monitor 43 is arranged in the cable force monitoring slot 42 The two ends of the cable force monitoring groove 42 are anchor blocks, and the anchor blocks are all used for the anchoring of stay cables 3;

The monitoring room 4B is arranged on the upper part of the cable receiving well 4, and the monitoring device 45 for the stay cable is arranged in the monitoring room 4B.

The four power stations 7 are provided on the land behind the four cable receiving wells 4 in a one-to-one correspondence.

The four groups of cable steering piers 8 are located on the shore slope on both sides of the tunnel and on the opposite shore side of the tunnel in a one-to-one correspondence, and are close to the four cable receiving wells 4 in a one-to-one correspondence; The cable steering piers 8 are all located at the maximum depth of the channel; the number of each group of cable steering piers 4 is half of the total number of stay cables 3; each cable steering pier 8 is a reinforced concrete pier structure with a pile foundation 80 at the bottom ; The bottom of each cable steering pier 8 is higher than the elevation of the water suspension tunnel 1 and not higher than the minimum bottom elevation of the channel; the interior of each cable steering pier 8 is set along the direction of the stay cable 3. A steering fairlead 81 is pre-embedded on the channel.

The cable ramp 9 is arranged on the bank slope between each group of cable steering piers 8 and the corresponding cable receiving well 4; and concrete surface.

Half of the multi-channel stay cables 3 are the bank side stay cables, and the other half are the opposite bank side stay cables; Stay cables; if two-way double cable planes are used, each stay cable 3 includes four stay cables connected to both sides of the water suspension tunnel 1 in pairs; one end of the shore-side stay cables is anchored at intervals On the cable anchors on the outer surfaces of the two sides of the water suspension tunnel 1 near the half length of the bank, the other ends of the stay cables on the bank side respectively pass through the two sets of cable steering piers 8 set on the bank and then follow the cable ramp. 9. Extend to the ground, and then anchor on the two stay cable anchor piers 4A set on this bank; one end of the stay cable 3 on the opposite bank is anchored at intervals on the outer surfaces of the two sides of the water suspension tunnel 1 close to the opposite bank. On the other side, the other ends of the stay cables on the opposite bank respectively pass through the two sets of cable steering piers 8 located on the opposite bank, and then extend to the ground along the cable ramp 9, and then anchor to the two cable anchor piers 4A located on the opposite bank. superior.

The stay cable 3 is mainly used to resist horizontal forces such as water flow force, and at the same time, in order to maintain the underwater stability of the suspended tunnel 1 in the water, the gravity of the suspended tunnel 1 in the water is slightly larger than the buoyancy. Therefore, the stay cable 3 bears the vertical force generated by the weight of part of the tunnel pipe at the same time. The stay cable 3 must have the performance requirements of wear resistance, corrosion resistance, high tensile strength and easy replacement. High molecular weight polyethylene fiber cable, and the floating weight ratio of the stay cable 3 in water is 1.

The cable anchor system of the underwater cable-stayed suspension tunnel of the present invention is mainly used for fixing the underwater suspension tunnel 1. The balance of the generated forces such as gravity, water flow force, wave force, etc., enables the underwater suspension tunnel 1 to be stable in the design position. The force transmission mode is that the load on the tunnel pipe section is transmitted to the stay cable anchor pier 4A through the stay cable 3 . The cable anchor system needs to meet the technical requirements of underwater jacking and installation of the tunnel pipe section during the construction period of the suspension tunnel and the anchorage and force monitoring requirements of the stay cable 3 during the service period of the suspension tunnel. The basic principles of design are reasonable force system, reliable technology, convenient construction, good durability and maintainability.

The stay cable 3 is anchored on the cable anchor pier 4A on the shore. The cable anchor pier 4A must be located on a stable foundation on the coast and meet the requirements of slope stability. The pullout resistance and the stability of the bank slope must be checked. . A cable force monitor 43 and an electric windlass 44 are arranged on the cable anchor pier 4A for monitoring the cable force. The monitoring of the cable force of the stay cable 3 and the replacement during the operation period are carried out in the cable monitoring room 4B on the cable anchor pier 4A. The stay cable 3 is extended to the ground along the underwater stay cable ramp 9 through the steering fairlead 81 in the stay cable steering pier 8, and is anchored on the stay cable anchor pier 4A; each stay cable 3 is individually configured with one The cable steering pier 8, the cable steering pier 8 is used for the steering of the stay cable 3 and is to reduce the elevation of the stay cable 3 in the water, so that it does not affect the navigation; the stay cable 3 is turned from the stay cable to the pier 8 The lower part of the steering fairlead 81 is passed through, and then extended along the cable ramp 9 to above the water surface, so as to facilitate the tensioning operation of the stay cable 3; when the stay cable 3 is tensioned, the stay cable turns to the pier 8 Due to the upward pulling force, the cable steering pier 8 must have sufficient pull-out resistance and the ability to bear horizontal loads. The bottom of the cable steering pier 8 is higher than the tunnel elevation, and not higher than the minimum bottom elevation of the channel, the angle between the cable surface and the horizontal direction is not greater than 45°, and the cable steering pier 8 must be located on a stable foundation within the bank slope, satisfying To meet the requirements of slope stability, the pullout resistance and bank slope stability must be checked. The slope surface of the stay cable ramp 9 is integral, that is, it includes the range of all the stay cables 3 on one side, which not only prevents the stay cables 3 from being worn, but also protects the bank slope.

The construction steps of the cable anchor system of the underwater cable-stayed suspension tunnel of the present invention are as follows:

Step 1: The cable turns the pile foundation of the pier 8 to sink the pile on the water.

Step 2: Construction of cofferdam 8 for cable steering pier;

Step 3: Cast-in-place construction of the cable steering pier 8;

Step 4: Construction of cable ramp 9;

Step 5: Concrete cast-in-place construction of cable anchor pier 4A;

Step 6: The temporary fairlead installation of the stay cable 3 on the cable steering pier 8;

Step 7: Remove the cofferdam of the cable steering pier 8;

Step 8: Installation of tunnel pipe sections, installation of stay cables 3, and initial tensioning;

Step 9: Adjust the cable force of the suspended tunnel 1 in the water;

Step 10: Install and seal the safety cable at the anchoring end of the stay cable 3.

The construction requirements of the cable anchor system of the underwater cable-stayed suspension tunnel of the present invention are:

The butt end of the stay cable 3 and the tunnel tube section is installed on the shore connection structure 2, and all of them are temporarily fixed on the tunnel tube section. The cable is anchored to the pier 4A. The stay cable 3 is pushed out of the landing structure 2 along with the top of the tunnel tube section, and then the traction rope is stretched to guide the stay cable 3 to the cable anchor pier 4A, and then the slope is adjusted according to the push of the tunnel tube section and the force requirements of the stay cable 3. Length and tension of cable 3. The length and tension of the stay cable 3 are adjusted by the electric windlass 44 on the cable anchor pier 4A, and the tension of the stay cable 3 is measured in real time by the cable force monitor 43 .

The cable steering pier 8 is located in the water, the pile foundation 80 can be constructed by a piling boat or a temporary platform on the water, and the concrete pier and ancillary facilities can be installed by using the cofferdam method to form dry construction conditions.

The part below the water surface of the cable ramp 9 can be excavated by a dredger for foundation trenches, riprap on the water for slope protection, divers to level the gravel foundation underwater, and the concrete surface layer is constructed by prefabricated installation method; the part above the water surface is carried out by excavators Earthwork excavation and foundation replacement, the concrete is cast-in-place, and temporary support structures can be set up if necessary.

The structural construction of the cable anchor shaft 4 is located on the shore, and the construction of the cable anchor pier 4A can adopt the cast-in-place method in the cofferdam.

The above embodiments are only for illustrating the present invention, rather than limiting the present invention. Those skilled in the relevant technical field can also make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalents The technical solution of the invention should also belong to the scope of the present invention and should be defined by the claims.

Claims (6)

1. A guy cable anchor system of an underwater cable-stayed suspension tunnel comprises a tunnel body, a butt-joint shore structure, a guy cable anchor system and a floating weight ratio adjusting system; the tunnel body comprises an underwater suspension tunnel and a land slope tunnel; it is characterized in that the preparation method is characterized in that,

the cable anchorage system adopts a bidirectional single cable surface or a bidirectional double cable surface and comprises four cable receiving wells, four groups of cable steering piers, a cable ramp and a plurality of stay cables; wherein,

the four inhaul cable receiving wells are correspondingly arranged on the shore side seashore at two sides of the tunnel and the opposite shore side seashore at two sides of the tunnel one by one; each cable receiving well comprises a cable anchorage pier and a monitoring room; the guy cable anchorage pier is arranged at the lower part of the guy cable receiving well; a cable guide device is arranged on the water side of the guy cable anchorage pier; a cable force monitoring groove is formed in the middle of the cable anchorage pier, a cable force monitor is arranged in the cable force monitoring groove, and anchorage blocks are arranged at two ends of the cable force monitoring groove; the rear end of the guy cable anchorage pier is provided with an electric anchor machine; the monitoring chamber is arranged at the upper part of the inhaul cable receiving well, and the inhaul cable monitoring device is arranged in the monitoring chamber;

the four groups of cable steering piers are correspondingly arranged on the bank side coast bank slopes on two sides of the tunnel and the opposite bank side coast bank slopes on two sides of the tunnel one by one and are close to the four cable receiving wells one by one; each group of stay cable steering piers are positioned at the maximum depth of the channel; the number of the stay cable steering piers in each group is half of the total number of the stay cables; the bottom of each guy cable steering pier is higher than the elevation of the underwater suspended tunnel and not higher than the minimum bottom elevation of the channel; a stay cable channel is arranged in each stay cable steering pier along the direction of a stay cable, and a steering cable guide is embedded in each stay cable channel;

the stay cable ramp is arranged on a bank slope between each group of stay cable steering piers and the corresponding stay cable receiving well;

one half of the plurality of stay cables is the shore side stay cable, and the other half is the opposite shore side stay cable; each stay cable comprises two stay cables which are respectively connected with two sides of the underwater suspension tunnel or four stay cables which are respectively connected with two sides of the underwater suspension tunnel in pairs; one end of the bank side inclined guy cable is anchored on guy cable anchors on the outer surfaces of two sides of the underwater suspended tunnel which is close to the half length of the bank at intervals, and the other end of the bank side inclined guy cable penetrates through two groups of guy cable steering piers arranged on the bank respectively and then extends to the ground along guy cable ramp ways and is anchored on two guy cable anchor piers arranged on the bank; one end of each opposite bank side inclined guy cable is anchored on guy cable anchors on the outer surfaces of the two sides of the water suspension tunnel close to the opposite bank at intervals, and the other end of each opposite bank side inclined guy cable penetrates through two groups of guy cable steering piers arranged on the opposite bank and then extends to the ground along a guy cable ramp and is anchored on two guy cable anchor piers arranged on the opposite bank.

2. A cable anchor system for an underwater cable-stayed suspension tunnel according to claim 1, wherein the cable anchor system further comprises four power stations each provided on the land ground behind the four cable receiving wells.

3. The cable anchor system of the underwater cable-stayed suspension tunnel according to claim 1 or 2, wherein the cable anchor pier is a reinforced concrete pier structure with a pile foundation at the lower part.

4. The cable anchor system of an underwater cable-stayed suspension tunnel according to claim 1 or 2, wherein each cable deflector pier is a reinforced concrete pier structure having a pile foundation at the lower part.

5. The cable anchor system of the underwater cable-stayed suspension tunnel according to claim 1 or 2, wherein the structure of the cable ramp is a riprap slope, a gravel cushion layer and a concrete surface layer in sequence from bottom to top.

6. A cable anchor system for an underwater cable-stayed suspension tunnel according to claim 1 or 2, wherein the stay cable is an ultra-high molecular weight polyethylene fiber cable, and the underwater buoyant weight ratio of the stay cable is 1.

Images