Method and system for controlling unbalance loading of TY piers in construction period

Abstract

The invention discloses a construction period TY pier unbalance loading control method and system, and the method comprises the steps: S100, preparing a balance weight in advance, transporting the balance weight to a TY pier of a to-be-erected beam, installing the balance weight on one side of the rear erected beam of the TY pier, and setting the force of the balance weight on the TY pier; s200, a box girder is slowly erected on the side, where the girder is firstly erected, of the TY pier, the force of a balance weight on the TY pier is continuously increased while the girder is dropped, and the stress at the two ends of the TY pier is kept within a safety difference value; s300, a box girder is slowly erected on the side, where the girder is erected, of the rear portion of the TY pier, the force of the balance weight on the TY pier is continuously reduced while the girder is dropped, and the stress of the two ends of the TY pier is kept within the safety difference value; and S400, after all the box girders on the two sides of the TY pier are erected, all the counterweights are removed. Ballast is additionally applied to one side of a rear frame beam of a TY pier, the weight is continuously increased when a beam is erected on one side of a first frame beam, and the weight is continuously reduced when a beam is erected on one side of the rear frame beam, so that the difference between loads at the two ends of the TY pier fluctuates within a normal range in the beam erecting process, and permanent damage to the TY pier caused by overlarge unbalance loading is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering, and more specifically, relates to a method and system for controlling the eccentric load of TY piers during the construction period. Background Art

[0002] In some municipal engineering projects, when erecting a bridge, it is necessary to not only ensure the bearing requirements of the bridge itself, but also consider its aesthetics during construction. In some urban viaducts and overpasses, due to the scarcity of land resources and the complexity of road planning, the smaller the floor area of the pier, the better. At this time, TY piers are used during construction. TY piers have the advantages of small floor area, high space utilization rate, and beautiful bridge shape, and have been widely used. However, during the use of TY piers, because the cross-section above is larger than the cross-section of the bottom support end, the situation of uneven left and right forces will occur. In this case, it will cause the bridge to overturn laterally, or the TY pier will be subjected to excessive eccentric load, resulting in damage to its structure and affecting the subsequent use of the bridge.

[0003] Currently, there are various anti-overturning and anti-falling beam strengthening devices for single-column piers on the market. After the paired hoop is attached to the upper end of the single-column pier, it is then fixed to the vertical plate of the paired bracket. In this way, the hoop fixes the bracket, and the inner surface of the bracket is symmetrically provided with a backing plate and a bearing seat in an L shape. The backing plate and the bearing seat can prevent the beam body from overturning laterally and falling longitudinally. Then, the arc section of the prestressed tie rod is limited inside the support member through the support member on the positioning plate. One end of the prestressed tie rod penetrates the sleeve, and the other end is fixed between the connecting plate and the bearing platform. In this way, prestress can be applied to the prestressed tie rod. When the bridge is subjected to eccentric load, the prestressed tie rod can provide a reverse pulling force, and the unbalanced force on the single-column pier can be transmitted to the stable bearing platform, effectively avoiding the overall overturning of the pier.

[0004] This kind of anti-overturning and anti-falling beam strengthening device for single-column piers can effectively prevent the bridge from overturning due to inconsistent vehicle weights on both sides during operation. However, during the erection process of the bridge, it is often necessary to erect the left and right box girders separately. This will cause the TY pier on the side erected first to be subjected to extremely large forces, while the other side is in an unloaded state. In this case, it will cause cracks in the bottom structure of the TY pier on the unloaded side due to tension, affecting the subsequent safety of the bridge. Moreover, the weight of the box girder itself is extremely large, and the reverse support force provided by the above strengthening device is too small to meet the support requirements. Therefore, a method and system for controlling the eccentric load of TY piers during the construction period are needed to balance the unilateral load during the bridge erection process and prevent permanent damage to the TY piers caused by excessive eccentric load. Summary of the Invention

[0005] In view of the above deficiencies or improvement requirements of the prior art, the present invention provides a method for controlling the eccentric load of TY piers during construction. By applying additional weights to the side of the TY pier where the beam is to be erected later, and continuously increasing the weights when erecting the beam on the side where the beam is erected first, and continuously reducing the weights when erecting the beam on the side where the beam is erected later, the difference in loads on both sides of the TY pier is kept fluctuating within a normal range during the entire beam erection process, preventing excessive eccentric load caused by too large a difference in loads at both ends, and avoiding permanent damage to the TY pier due to excessive eccentric load.

[0006] To achieve the above objectives, an embodiment of the present invention provides a method for controlling the eccentric load of TY piers during construction, which specifically includes the following steps:

[0007] S100. Prepare the counterweights in advance and transport them to the location of the TY pier where the beam is to be erected. Install the counterweights on the side of the TY pier where the beam is to be erected later, and set the force exerted by the counterweights on the TY pier.

[0008] S200. Slowly erect the box girder on the side of the TY pier where the beam is erected first. While lowering the beam, continuously increase the force exerted by the counterweights on the TY pier to keep the forces at both ends of the TY pier within a safe difference.

[0009] S300. Slowly erect the box girder on the side of the TY pier where the beam is erected later. While lowering the beam, continuously reduce the force exerted by the counterweights on the TY pier to keep the forces at both ends of the TY pier within a safe difference.

[0010] S400. After all the box girders on both sides of the TY pier are erected, remove all the counterweights.

[0011] Further, during the beam erection process, it is necessary to monitor the force exerted by the box girder on the TY pier in real time to control the increase and decrease of the counterweights. Specifically:

[0012] S501. During hoisting, install pressure sensors on both sides of the capping beam of the TY pier, and measure the pressure generated by the box girder and the counterweights through the pressure sensors.

[0013] S502. Set the maximum value of the eccentric load at both ends of the TY pier, and calculate the loads at both ends based on the measured pressure and the center of the force to calculate the eccentric load on the TY pier.

[0014] S503. Set the maximum tensile load value of the TY pier determined according to the material properties to limit the calculated eccentric load.

[0015] S504. Increase or decrease the counterweights according to the calculated eccentric load and the maximum tensile load value to keep the actual eccentric load always less than the maximum tensile load value.

[0016] Further, in step S502, the eccentric load ΔM(t) on the TY pier is specifically:

[0017] ΔM(t) = |Ml (t)-M r (t)|·α(t),

[0018] Wherein, M l (t) is the variation of the left torque with time,

[0019] M r (t) is the variation of the right torque with time,

[0020] α(t) is the safety factor varying with time.

[0021] Furthermore, the variation of the left torque with time M l (t) is specifically:

[0022]

[0023] Wherein, F l (τ) is the pressure measured on the left side,

[0024] k(τ) is the calibration coefficient varying with time, used to adjust the torque difference caused by the installation position,

[0025] W m (τ) is the weight of the left box girder,

[0026] Wc(τ) is the weight of the left counterweight,

[0027] D is the distance from the center of the box girder or the counterweight to the center of the TY pier, and the two are equal,

[0028] W w (τ) is the external disturbing force;

[0029] The variation of the right torque with time M r (t) is specifically:

[0030]

[0031] Wherein, F r (τ) is the pressure measured on the right side.

[0032] Furthermore, in step S504, in order to maintain the actual eccentric load ΔM(t) less than the maximum tensile load value F max (t), it is necessary to adjust the counterweight by W c (τ), specifically:

[0033]

[0034] Wherein, γ(t) is the adjustment rate factor, used to control the amplitude of each adjustment,

[0035] ∈(t) is the construction error;

[0036] Control ΔM(t) ≤ F max (t)·δ(t), where δ(t) is the system response time factor to ensure stability during the adjustment process.

[0037] Furthermore, after the bottom of the box girder contacts the capping beam of the TY pier, it is necessary to control the force exerted by the crane on the box girder to decrease slowly until the entire weight of the box girder falls entirely on the capping beam of the TY pier. The specific method is as follows:

[0038] S601. Set an elastic buffer device at the top of the TY pier. During the beam lowering process, the bottom of the box girder first contacts this elastic buffer device;

[0039] S602. After contacting the elastic buffer device, continue to lower the beam slowly downward. The elastic buffer device is compressed by the force, generating a reaction force on the box girder, causing the TY pier to bear part of the gravity of the box girder;

[0040] S603. During the process of lowering the beam downward, monitor the force exerted by the box girder on the TY pier, and correspondingly increase or decrease the counterweight on the TY pier to keep the eccentric load on the TY pier always within the normal range;

[0041] S604. Continue to lower the box girder, compressing the elastic buffer device downward until the entire gravity of the box girder is supported entirely by the elastic buffer device;

[0042] S605. After the box girder is completely supported by the elastic buffer device, lock the elastic buffer device. Set an adjusting jack between the box girder and the capping beam of the TY pier. After slightly lifting the box girder, remove the elastic buffer device;

[0043] S606. Then retract the adjusting jack to make the box girder fall on the bearing padstone at the top of the TY pier, completing the beam lowering.

[0044] Furthermore, the specific operation is as follows:

[0045] R100. Arrange sliding tracks on the capping beam of the TY pier, and formwork and pour multiple precast blocks on the pedestal of the TY pier;

[0046] R200. Use a floating crane to hoist the precast blocks to the corresponding positions on the sliding tracks of the capping beam on the side of the TY pier where the beam is erected first, and make temporary fixation;

[0047] R300. Set a bearing padstone at the top of the capping beam, and set an adjusting jack beside the bearing padstone, ensuring that the top of the jack is higher than the upper surface of the precast block;

[0048] R400. Hoist the box girder and make it slowly fall on the adjusting jack on the capping beam on the side of the TY pier where the beam is erected first. At the same time, continuously add precast blocks on the sliding tracks of the capping beam on the side where the beam is erected later until the box girder on the side where the beam is erected first completely falls on the adjusting jack;

[0049] R500. Lift the box girder and slowly lower it onto the adjusting jack on the capping beam on the side of the later - erected beam after it is placed on the TY pier. At the same time, continuously reduce the precast blocks on the slideway on the side of the later - erected beam of the capping beam until the box girder on the side of the later - erected beam completely falls onto the adjusting jack.

[0050] R600. Slide the precast blocks on the slideway towards the middle part of the capping beam to the middle position between the two box girders, and carry out block - by - block hoisting and demolition. After the demolition is completed, adjust the adjusting jack so that both box girders fall onto the bearing stones.

[0051] Furthermore, step R400 specifically further includes the following steps:

[0052] R401. The front fulcrum of the bridge - erecting machine falls on the position slightly in the middle of the TY pier, and increase the precast blocks to keep the eccentric load within the normal range.

[0053] R402. Move the bridge - erecting machine forward so that the bridge - erecting machine passes through the hole of the TY pier. At the same time, tow the precast blocks to move along the slide, and always keep the bridge - erecting machine and the precast blocks in a mirror - image position relative to the central axis of the TY pier.

[0054] R403. Add counterweights while hoisting the box girder to keep the eccentric load in dynamic balance within the normal range.

[0055] R404. After the box girder on the side of the first - erected beam is erected, dismantle the bridge - erecting machine and remove some counterweights at the same time.

[0056] Furthermore, the specific operation is as follows:

[0057] T100. Reserve holes on the capping beam at the top of the TY pier, pre - place multiple sand barrels on the bearing platform at the bottom of the TY pier, fill the sand barrels with heavy objects including sand, and set a winch at the center position of the capping beam.

[0058] T200. The steel wire rope of the winch is lowered from the reserved hole on the capping beam to the water surface, place the sand barrels in the water, and tie them with steel wires to tow the counterweight blocks.

[0059] T300. Use the winch to lift the sand barrels up a part as the initial counterweight, then set bearing stones on the top of the capping beam, and set adjusting jacks beside the bearing stones.

[0060] T400. Hoist the box girder and slowly lower it onto the adjusting jack on the capping beam on the side of the first - erected beam of the TY pier. At the same time, continuously lift the sand barrels on the winch on the side of the later - erected beam to increase the counterweight until the box girder on the side of the first - erected beam completely falls onto the adjusting jack.

[0061] T500. Lift the box girder and slowly lower it onto the adjusting jack on the capping beam on the side of the girder erection after the TY pier. At the same time, continuously lower the sand bucket on the winch on the side of the girder erection after the TY pier to reduce the counterweight until the box girder on the side of the girder erection after the TY pier completely falls onto the adjusting jack.

[0062] T600. Completely lower the sand bucket into the water, remove the sand bucket and dismantle the winch on the top of the TY pier.

[0063] Furthermore, the specific operation is as follows:

[0064] G100. Reserve holes on the capping beam on the top of the TY pier, drive steel pipe columns in the water at the bottom of the bridge, and set a plurality of counterweight jacks on the steel pipe columns.

[0065] G200. Use steel strands to connect one side of the top of the TY pier with the counterweight jack through the reserved holes on the capping beam.

[0066] G300. Then set a bearing pad on the top of the capping beam and set an adjusting jack beside the bearing pad. After the counterweight jack is pulled back to the design tension, it is anchored as the initial counterweight.

[0067] G400. Lift the box girder and slowly lower it onto the adjusting jack on the capping beam on the side of the girder erection first after the TY pier. At the same time, continuously tighten the counterweight jack on the side of the girder erection after the TY pier to increase the counterweight until the box girder on the side of the girder erection first after the TY pier completely falls onto the adjusting jack.

[0068] G500. Lift the box girder and slowly lower it onto the adjusting jack on the capping beam on the side of the girder erection after the TY pier. At the same time, continuously loosen the counterweight jack on the side of the girder erection after the TY pier to reduce the counterweight until the box girder on the side of the girder erection after the TY pier completely falls onto the adjusting jack.

[0069] G600. Completely loosen the counterweight jack to unload all the counterweights, and dismantle the counterweight jack and the steel strands.

[0070] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0071] 1. The unbalanced load control method of the present invention applies additional ballast to the side of the girder erection after the TY pier, continuously increases the ballast when erecting the girder on the side of the girder erection first, and continuously reduces the ballast when erecting the girder on the side of the girder erection after the TY pier, so that during the entire girder erection process, the difference in loads on both sides of the TY pier always fluctuates within a normal range, preventing the unbalanced load from being too large due to the large difference in loads at both ends, and avoiding permanent damage to the TY pier caused by excessive unbalanced load.

[0072] 2. The eccentric load control method of the present invention enlarges the stroke of lowering the box girder onto the TY pier by setting an elastic buffer device at the top of the TY pier, thereby lengthening the process from when the gravity of the box girder begins to act on the TY pier to when it fully acts on the TY pier. Thus, the effect of the gravity of the box girder acting on the TY pier can be controlled by controlling the lowering speed and stroke, so that the operator can timely increase the counterweight and better control the magnitude of the eccentric load.

[0073] 3. The eccentric load control method of the present invention gives different counterweight loading methods according to TY piers at different positions, enabling better loading for each TY pier and making it easier to control the eccentric load of TY piers in different environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a schematic flow chart of a method for controlling the eccentric load of a TY pier during the construction period according to an embodiment of the present invention;

[0075] Figure 2 It is a schematic flow chart of controlling the increase and decrease of counterweight in a method for controlling the eccentric load of a TY pier during the construction period according to an embodiment of the present invention;

[0076] Figure 3 It is a schematic flow chart of beam lowering buffer in a method for controlling the eccentric load of a TY pier during the construction period according to an embodiment of the present invention;

[0077] Figure 4 It is a schematic flow chart of the specific process of a method for controlling the eccentric load of a TY pier during the construction period according to an embodiment of the present invention;

[0078] Figure 5 It is a schematic flow chart of step R400 in a method for controlling the eccentric load of a TY pier during the construction period according to an embodiment of the present invention;

[0079] Figure 6 It is a schematic flow chart of the specific process of the second method for controlling the eccentric load of a TY pier during the construction period according to an embodiment of the present invention;

[0080] Figure 7 It is a schematic flow chart of the specific process of the third method for controlling the eccentric load of a TY pier during the construction period according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0081] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0082] As Figure 1As shown in the figure, during the bridge erection process of the TY pier, when erecting a box girder, the TY pier will be severely unevenly stressed on both sides. The unloaded side will be in tension, resulting in large tensile stresses at the intersection of the inclined leg and the capping beam and at the intersection of the inclined leg and the pier body. After calculation, the tensile stress generated during the beam erection process has exceeded the bearing limits of the concrete and steel bars, and cracks are very likely to occur, ultimately affecting the safety of the bridge in use. Therefore, the present invention provides a method for controlling the eccentric load of the TY pier during the construction period, which specifically includes the following steps:

[0083] S100. Prepare the counterweight in advance and transport it to the TY pier where the beam is to be erected. Install the counterweight on the side of the TY pier where the beam will be erected later, and set the force of the counterweight on the TY pier;

[0084] S200. Slowly erect the box girder on the side of the TY pier where the beam is erected first. While lowering the beam, continuously increase the force of the counterweight on the TY pier to keep the forces at both ends of the TY pier within a safe difference;

[0085] S300. Slowly erect the box girder on the side of the TY pier where the beam is erected later. While lowering the beam, continuously reduce the force of the counterweight on the TY pier to keep the forces at both ends of the TY pier within a safe difference;

[0086] S400. After all the box girders on both sides of the TY pier are erected, remove all the counterweights.

[0087] In step S100, when controlling the eccentric load, it is necessary to consider that the eccentric loads on both sides of the TY pier should not be too large. Therefore, during the process of increasing or decreasing the counterweight, it is necessary to control the size of the counterweight to avoid generating an eccentric load towards the counterweight side. In the subsequent steps S200 and S300, while lowering the beams on both sides, it is necessary to increase or decrease the counterweight so that the eccentric loads on both sides fluctuate within a safe range to prevent the eccentric load from being too large due to the counterweight.

[0088] In steps S200 and S300, through calculation, the standard value of the tensile strength of C45 is 2.51 MPa, and the unbalanced force generating a tensile force of 2.5 MPa is 800 t. Therefore, during the process of erecting the box girder, the maximum eccentric load of the TY pier should be maintained at about 2.5 MPa. And control the distances from the centers of the box girder and the counterweight to the center point of the TY pier to be the same, and each box girder should be supported by at least two TY piers.

[0089] As Figure 2 shown, during the beam erection process, it is necessary to monitor the force exerted by the box girder on the TY pier in real time to control the increase and decrease of the counterweight. Specifically:

[0090] S501. During hoisting, pressure sensors are installed on both sides of the capping beam of the TY pier, and the pressure generated by the beam erection tools on them is measured through the pressure sensors;

[0091] S502. Set the maximum eccentric load at both ends of the TY pier, and calculate the loads at both ends according to the measured pressure and the stress center point to calculate the eccentric load on the TY pier;

[0092] S503. Set the maximum tensile load value of the TY pier determined according to the material properties to limit the calculated eccentric load;

[0093] S504. Increase or decrease the counterweight according to the calculated eccentric load and the maximum tensile load value, so that the actual eccentric load always remains less than the maximum tensile load value.

[0094] In step S502, the eccentric load ΔM(t) on the TY pier is specifically:

[0095] ΔM(t) = |M l (t) - M r (t)|·α(t),

[0096] where M l (t) is the change of the left - hand moment with time,

[0097] M r (t) is the change of the right - hand moment with time,

[0098] α(t) is the safety factor changing with time.

[0099] The change of the left - hand moment with time M l (t) is specifically:

[0100]

[0101] where F l (τ) is the pressure measured on the left side,

[0102] k(τ) is the calibration coefficient changing with time, used to adjust the moment difference caused by the installation position,

[0103] W m (τ) is the weight of the left - hand box girder,

[0104] W c (τ) is the weight of the left - hand counterweight,

[0105] D is the distance from the center of the box girder or the counterweight to the center of the TY pier, and the two are equal,

[0106] W w (τ) is the external disturbing force;

[0107] The change of the right - hand moment with time M r (t) is specifically:

[0108]

[0109] Among them, F r (τ) is the pressure measured on the right side.

[0110] In step S503, the maximum tensile load value F of the TY pier max (t) is:

[0111] F max (t) = σ(t)·A(t)·β(t)·E age (t),

[0112] Among them, σ(t) is the function of the maximum allowable tensile stress of the material varying with time and temperature,

[0113] A(t) is the function of the tensile cross-sectional area varying with temperature,

[0114] β(t) is the influence of temperature change on the material properties,

[0115] E age (t) is the aging effect of the material.

[0116] In step S504, in order to maintain the actual eccentric load ΔM(t) less than the maximum tensile load value F max (t), it is necessary to adjust the counterweight W c (τ), specifically:

[0117]

[0118] Among them, γ(t) is the adjustment rate factor, used to control the amplitude of each adjustment,

[0119] ∈(t) is the construction error;

[0120] Control ΔM(t) ≤ F max (t)·δ(t), where δ(t) is the system response time factor, used to ensure the stability during the adjustment process.

[0121] During the hoisting process of the box girder, after the bottom of the box girder contacts the capping beam of the TY pier, when lowering the box girder further, slightly lowering it will cause the entire weight of the box girder to directly fall on one side of the TY pier, resulting in an instantaneous increase in the eccentric load and thus an increase in the tensile stress of the TY pier. And increasing too much counterweight in advance will also cause an excessive eccentric load on the opposite side of the TY pier, which will also increase the tensile stress of the TY pier. Therefore, after the bottom of the box girder contacts the capping beam of the TY pier, it is necessary to control the force exerted by the crane on the box girder to decrease slowly until the entire weight of the box girder falls on the capping beam of the TY pier.

[0122] As Figure 3 shown, during the beam lowering process, the specific method is:

[0123] S601. Set an elastic buffer device at the top of the TY pier. During the process of girder lowering, the bottom of the box girder first contacts this elastic buffer device;

[0124] S602. After contacting the elastic buffer device, continue to slowly lower the girder downward. The elastic buffer device is compressed under force, generating a reaction force on the box girder, causing the TY pier to bear part of the gravity of the box girder;

[0125] S603. During the process of lowering the girder downward, monitor the force exerted by the box girder on the TY pier, and correspondingly increase or decrease the counterweight on the TY pier, so that the eccentric load on the TY pier is always within the normal range;

[0126] S604. Continue to lower the box girder, compressing the elastic buffer device downward until all the gravity of the box girder is supported by the elastic buffer device;

[0127] S605. After the box girder is completely supported by the elastic buffer device, lock the elastic buffer device. Set an adjusting jack between the box girder and the capping beam of the TY pier. After slightly jacking up the box girder, remove the elastic buffer device;

[0128] S606. Then retract the adjusting jack to make the box girder fall on the bearing pad stone at the top of the TY pier, completing the girder lowering.

[0129] Embodiment 1

[0130] As Figure 4 shown, in this embodiment, by placing a pressing block on one side of the TY pier where the girder is erected later, a counterweight is formed. At this time, it is applicable to the transition pier. At this time, the bottom of the TY pier is provided with a capping platform exposed. The eccentric load control method is specifically as follows:

[0131] R100. Arrange a slideway on the capping beam of the TY pier, and formwork and pour multiple precast pressing blocks on the capping platform of the TY pier;

[0132] R200. Use a floating crane to hoist the precast pressing blocks to the corresponding positions on the slideway of the capping beam on one side of the TY pier where the girder is erected later, and make temporary fixation;

[0133] R300. Set a bearing pad stone on the top of the capping beam, and set an adjusting jack beside the bearing pad stone, ensuring that the top of the jack is higher than the upper surface of the precast pressing block;

[0134] R400. Hoist the box girder and make it slowly fall on the adjusting jack on the capping beam on one side of the TY pier where the girder is erected first. At the same time, continuously add precast pressing blocks on the slideway of the capping beam on the side where the girder is erected later until the box girder on the side where the girder is erected first completely falls on the adjusting jack;

[0135] R500, hoist the box beam and make it slowly fall on the adjusting jack of the cap beam on the rear beam side of the TY pier, and at the same time, continuously reduce the prefabricated pressing blocks on the cap beam slideway on the rear beam side until the box beam on the rear beam side completely falls on the adjusting jack;

[0136] R600, slide the prefabricated pressing block on the slideway toward the middle part of the cap beam to the middle position of the two box beams, and lift and remove it in blocks. After the removal is completed, adjust the adjusting jack so that both box beams fall on the cushion stone.

[0137] like Figure 5 As shown, in step R400, since the bridge erection machine has its own weight and is installed on one side of the bridge, its weight cannot be ignored compared to the box girder. Therefore, the influence of the bridge erection machine's weight needs to be considered in the process of calculating the eccentric load. Step R400 specifically includes the following steps:

[0138] R401, the front support point of the bridge erecting machine is located in the middle of the TY pier, and prefabricated pressure blocks are added to keep the eccentric load within the normal range;

[0139] R402, move the bridge erection machine forward to make it pass through the hole of the TY pier, and at the same time pull the prefabricated pressing block to move along the slide, always keeping the bridge erection machine and the prefabricated pressing block in a mirror position relative to the central axis of the TY pier;

[0140] R403. Add counterweight while lifting the box girder to ensure that the eccentric load is in dynamic balance within the normal range;

[0141] R404. After the box girder on one side is erected, dismantle the bridge-erecting machine and remove part of the counterweight at the same time.

[0142] Example 2

[0143] like Figure 6 As shown, since the method of using the pier top weight in Example 1 is all operated on the pier top, it is also necessary to hoist the prefabricated pressure block with a very large deadweight to the pier top, which makes the method difficult to implement. In addition, since the space on the pier top is small and the space for stacking is limited, the operation is restricted. Therefore, this embodiment provides another method for controlling the eccentric load of the TY pier during the construction period to reduce the pier top operation, which specifically includes the following steps:

[0144] T100, reserve holes on the cap beam at the top of the TY pier, place multiple sand buckets on the capping platform at the bottom of the TY pier, put heavy objects including sand in the sand buckets, and set a winch at the center of the cap beam;

[0145] T200, the wire rope of the winch is lowered to the water surface through the reserved hole on the cap beam, the sand bucket is placed in the water and tied with steel wire to pull the counterweight;

[0146] T300. Use a winch to lift the sand bucket partially as the initial counterweight. Then, set a bearing block on the top of the capping beam and set an adjusting jack beside the bearing block.

[0147] T400. Lift and install the box girder, and slowly lower it onto the adjusting jack on the capping beam on the side of the first - erected beam of the TY pier. At the same time, continuously lift the sand bucket on the winch on the side of the later - erected beam to increase the counterweight until the box girder on the side of the first - erected beam completely falls onto the adjusting jack.

[0148] T500. Lift and install the box girder, and slowly lower it onto the adjusting jack on the capping beam on the side of the later - erected beam of the TY pier. At the same time, continuously lower the sand bucket on the winch on the side of the later - erected beam to reduce the counterweight until the box girder on the side of the later - erected beam completely falls onto the adjusting jack.

[0149] T600. Completely lower the sand bucket into the water, remove the sand bucket and dismantle the winch on the top of the TY pier.

[0150] In step T200, since there is buoyancy of the sand bucket in water, control the depth of the sand bucket immersed in water through the winch to change the pulling force on the winch, thereby changing the counterweight. Because the density of the heavy object in the sand bucket is much higher than the density of water, even if it is completely immersed in water, it will cause excessive counterweight and too large side load on the opposite side. At this time, reduce the amount of heavy object in the sand bucket to lower the overall density of the sand bucket, and increase the number of sand buckets to meet the weight requirement of the counterweight.

[0151] Example 3

[0152] As Figure 7 shown, during the actual construction process, since the intermediate piers are all in deep water, and in this case, there is no capping beam above the water surface at the bottom of the TY pier, it is not convenient to operate tools such as sand buckets. Therefore, this example provides a third method for controlling the eccentric load of the TY pier during the construction period, including the following steps:

[0153] G100. Reserve holes on the capping beam at the top of the TY pier, drive steel pipe columns in the water at the bottom of the bridge, and set multiple counterweight jacks on the steel pipe columns.

[0154] G200. Use steel strands to connect one side at the top of the TY pier with the counterweight jack through the reserved holes on the capping beam.

[0155] G300. Then, set a bearing block on the top of the capping beam and set an adjusting jack beside the bearing block. After the counterweight jack is pulled back to the design tension, anchor it as the initial counterweight.

[0156] G400. Lift and install the box girder, and slowly lower it onto the adjusting jack on the capping beam on the side of the first - erected beam of the TY pier. At the same time, continuously tighten the counterweight jack on the side of the later - erected beam to increase the counterweight until the box girder on the side of the first - erected beam completely falls onto the adjusting jack.

[0157] G500. Lift the box girder and slowly lower it onto the adjusting jack on the capping beam on the side of the girder erection after it reaches the TY pier. At the same time, continuously loosen the counterweight jack on the side of the girder erection to reduce the counterweight until the box girder on the side of the girder erection completely lands on the adjusting jack.

[0158] G600. Completely loosen the counterweight jack to unload all the counterweights, and then remove the counterweight jack and the steel strand.

[0159] Example 4

[0160] During the erection of the last girder, due to the large span, the weight of the box girder on the last TY pier is relatively large. And after the erection of one box girder is completed, the erection of the other box girder needs to wait for half a year or even longer. Therefore, in this example, a concrete-filled steel tube support is used to support the side of the previously erected girder to ensure that the transverse offset of the capping beam of the TY pier during the erection of the segmental girder is within the controllable range and prevent the TY pier from being damaged due to long-term overweight and offset loading. The steel tube support is set on the TY pier foundation. The steel tubes are processed in sections of 6m, and the concrete in the steel tubes is poured in the backfield. The assembly of the concrete-filled steel tube support is carried out after the prestress construction of the TY pier is completed.

[0161] During the pouring process, the following matters need to be noted:

[0162] ① Before pouring, check whether there are sundries and accumulated water in the tube. If there are, clean them up and moisten the surface.

[0163] ② The concrete in the tube is poured in a layered manner with a layer thickness of 50cm. During pouring, use an insertion vibrator to vibrate the concrete in the tube layer by layer. The vibrator is inserted vertically into the concrete, inserted quickly and pulled out slowly, and inserted 5 - 10cm into the next layer of concrete. The concrete is vibrated until the surface is flat and oozes slurry and no more bubbles appear.

[0164] ③ After the pouring of each section of concrete is completed, when the strength reaches 10MPa, grind the surface at the joint position to ensure that the top surface of the concrete is flat, which is beneficial to the installation of the on-site steel pipe piles in the later stage.

[0165] ④ After the pouring of each steel pipe column is completed, remove the floating slurry on the top of the steel pipe. After the concrete begins to set, cover it with geotextile for curing.

[0166] The concrete in the tube is required to reach the design strength requirement, without voids and without separating and debonding from the tube wall. The inspection of the concrete strength is determined through test blocks cured under the same conditions. The voids and debonding of the concrete in the tube are inspected by the knocking method.

[0167] When inspecting the concrete in the pipe by the percussion method, it is required to conduct a 100% percussion inspection for each section and each steel pipe column, and at least 2 inspections should be carried out. The two inspection times are 7 days and 28 days after concrete pouring respectively, and it is required that the first inspection time after concrete pouring shall not be carried out within 7 days. Four points are taken at equal distances along the periphery of the steel pipe, and the bottom of the section is knocked to the top of the section. It is required that the vertical spacing of the steel hammer percussion shall not exceed 50 cm.

[0168] If it is found that the local concrete is not dense and exceeds the allowable void ratio of the specification, drill holes in the steel pipe wall and grout for reinforcement. The strength of the grouting liquid should be higher than the strength of the concrete in the steel pipe. After grouting reinforcement, plug and weld the drilled holes flat.

[0169] Since the TY pier cap has been constructed, the bottom embedded parts of the concrete-filled steel pipe support are set on the pier cap by the method of implanting steel bars. After the embedded steel plate on the pier cap is anchor welded with the steel bars, the space between the steel plate and the pier cap surface is filled with grouting material to ensure the density between the top surface of the pier cap and the embedded plate.

[0170] The bottom curve of the TY pier capping beam has a large radian. To ensure the force of the concrete-filled steel pipe support, a reinforced concrete cross beam is set on the top of the column, and the concrete cross-sectional size is 1.5×1 m (height×width).

[0171] The top layer steel bars and the middle part of the concrete cross beam are connected through the embedded sleeves during the construction of the capping beam. After the construction of the capping beam is completed, the surface concrete at the embedded position is chiseled to expose the sleeves, and the main steel bars and the middle part of the stirrups are connected into a whole through the sleeves. After the steel bar installation is completed, the formwork installation is carried out.

[0172] Embodiment 5

[0173] The embodiment of the present invention provides a construction period TY pier eccentric load control system, including:

[0174] The first counterweight module is used to prepare the counterweight in advance, transport it to the TY pier where the beam is to be erected, install the counterweight on one side of the TY pier for the beam erected later, and set the force of the counterweight on the TY pier;

[0175] The first beam erection module is used to slowly erect the box girder on one side of the TY pier where the beam is erected first. While the beam is being lowered, the force of the counterweight on the TY pier is continuously increased to keep the forces at both ends of the TY pier within a safe difference;

[0176] The second beam erection module is used to slowly erect the box girder on one side of the TY pier where the beam is erected later. While the beam is being lowered, the force of the counterweight on the TY pier is continuously reduced to keep the forces at both ends of the TY pier within a safe difference;

[0177] The second counterweight module is used to remove all the counterweights after the box girders on both sides of the TY pier are all erected.

[0178] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for controlling eccentric load of TY pier during construction period, characterized in that: The specific steps include: S100, prepare the counterweight in advance and transport it to the TY pier where the beam is to be erected, install the counterweight on one side of the beam erected behind the TY pier, and set the force of the counterweight on the TY pier; S200, slowly erect the box beam on the side of the TY pier where the beam is first erected, and continuously increase the force of the counterweight on the TY pier while lowering the beam, so that the force on both ends of the TY pier remains within the safety difference; S300, slowly erect the box beam on the side behind the TY pier, and continuously reduce the force of the counterweight on the TY pier while lowering the beam, so that the force on both ends of the TY pier remains within the safety difference; After all the box girders on both sides of S400 and TY piers are erected, all counterweights are removed.

2. A method for controlling eccentric load of TY pier during construction period according to claim 1, characterized in that: During the beam erection process, the force exerted by the box beam on the TY pier needs to be monitored in real time to control the increase or decrease of the counterweight, specifically: S501. During hoisting, pressure sensors are installed on both sides of the cap beam of the TY pier to measure the pressure exerted on it by the box beam and the counterweight through the pressure sensors; S502, setting the maximum value of the eccentric load at both ends of the TY pier, and calculating the loads at both ends according to the measured pressure and the center point of force to calculate the eccentric load on the TY pier; S503, setting a maximum tensile load value of the TY pier determined according to material properties, so as to limit the calculated eccentric load; S504. According to the calculated eccentric load and maximum tensile load value, the counterweight is increased or decreased so that the actual eccentric load is always kept smaller than the maximum tensile load value.

3. A method for controlling eccentric load of TY pier during construction period according to claim 2, characterized in that: In step S502, the eccentric load ΔM(t) on the TY pier is specifically: ΔM(t)=|M l (t)-M r (t)|·α(t), Among them, M l (t) is the change of the torque on the left side with time, M r (t) is the change of the torque on the right side with time, α(t) is the safety factor that varies with time.

4. A method for controlling eccentric load of TY pier during construction period according to claim 3, characterized in that: The left moment changes with time M l (t), specifically: Among them, F l (τ) is the pressure measured on the left side, k(τ) is a time-varying calibration factor used to adjust for torque differences due to mounting position. W m (τ) is the weight of the left box girder, W c (τ) is the weight of the left counterweight, D is the distance from the center of the box girder or counterweight to the center of the TY pier, and the two are equal. W w (τ) is the external disturbance force; The change of the right moment M with time r (t), specifically: Among them, F r (τ) is the pressure measured on the right side.

5. A method for controlling eccentric load of TY pier during construction period according to claim 4, characterized in that: In step S504, in order to maintain the actual eccentric load ΔM(t) less than the maximum tensile load value F max (t), the counterweight needs to be W c (τ) is adjusted, specifically: Among them, γ(t) is the adjustment rate factor, which is used to control the amplitude of each adjustment. ∈(t) is the construction error; Control ΔM(t)≤F max (t)·δ(t), where δ(t) is the system response time factor, which is used to ensure stability during the adjustment process.

6. A method for controlling eccentric load of TY piers during construction according to any one of claims 1 to 5, characterized in that: After the bottom of the box girder contacts the cap beam of the TY pier, the force applied by the crane to the box girder needs to be controlled to slowly decrease until the weight of the entire end box girder falls on the cap beam of the TY pier. The specific method is: S601. An elastic buffer device is arranged on the top of the TY pier, and during the beam dropping process, the bottom of the box beam contacts the elastic buffer device first; S602, after contacting the elastic buffer device, the beam continues to be slowly dropped downward, the elastic buffer device is compressed, and a reaction force is generated on the box beam, so that the TY pier bears part of the weight of the box beam; S603, during the process of lowering the beam, monitor the force applied by the box beam to the TY pier, and increase or decrease the counterweight on the TY pier accordingly, so that the eccentric load on the TY pier is always within a normal range; S604, continue to lower the box girder, and compress the elastic buffer device downward until the entire weight of the box girder is supported by the elastic buffer device; S605. After the box girder is fully supported by the elastic buffer device, lock the elastic buffer device, set an adjustment jack between the box girder and the cap beam of the TY pier, lift the box girder slightly, and then remove the elastic buffer device; S606. Retract and adjust the jacks again to allow the box girder to fall on the pad stone at the top of the TY pier, completing the beam drop.

7. A method for controlling eccentric load of TY piers during construction according to any one of claims 1 to 5, characterized in that: The specific operations are: R100. Arrange a slideway on the cap beam of the TY pier, and cast multiple prefabricated blocks on the cap of the TY pier; R200, use floating crane to hoist the prefabricated pressing block to the corresponding position of the slideway on the cap beam on the rear beam side of the TY pier, and temporarily fix it; R300, set a cushion stone on the top of the cap beam, and set an adjustable jack next to the cushion stone to ensure that the top of the jack is higher than the upper surface of the prefabricated pressing block; R400, hoist the box beam and make it slowly fall on the adjusting jack of the cap beam on the first beam erection side of the TY pier, and at the same time, continuously add prefabricated pressure blocks on the cap beam slideway on the rear beam erection side until the box beam on the first beam erection side completely falls on the adjusting jack; R500, hoist the box beam and make it slowly fall on the adjusting jack of the cap beam on the rear beam side of the TY pier, and at the same time, continuously reduce the prefabricated pressing blocks on the cap beam slideway on the rear beam side until the box beam on the rear beam side completely falls on the adjusting jack; R600, slide the prefabricated pressing block on the slideway toward the middle part of the cap beam to the middle position of the two box beams, and lift and remove it in blocks. After the removal is completed, adjust the adjusting jack so that both box beams fall on the cushion stone.

8. A method for controlling eccentric load of TY pier during construction period according to claim 7, characterized in that: Step R400 specifically also includes the following steps: R401, the front support point of the bridge erecting machine is located in the middle of the TY pier, and prefabricated pressure blocks are added to keep the eccentric load within the normal range; R402, move the bridge erection machine forward to make it pass through the hole of the TY pier, and at the same time pull the prefabricated pressing block to move along the slide, always keeping the bridge erection machine and the prefabricated pressing block in a mirror position relative to the central axis of the TY pier; R403. Add counterweight while lifting the box girder to ensure that the eccentric load is in dynamic balance within the normal range; R404. After the box girder on one side is erected, dismantle the bridge-erecting machine and remove part of the counterweight at the same time.

9. A method for controlling eccentric load of TY piers during construction according to any one of claims 1 to 5, characterized in that: The specific operations are: T100, reserve holes on the cap beam at the top of the TY pier, place multiple sand buckets on the capping platform at the bottom of the TY pier, put heavy objects including sand in the sand buckets, and set a winch at the center of the cap beam; T200, the wire rope of the winch is lowered to the water surface through the reserved hole on the cap beam, the sand bucket is placed in the water and tied with steel wire to pull the counterweight; T300, use the winch to lift a part of the sand bucket as the initial counterweight, then set a pad stone on the top of the cap beam, and set an adjusting jack next to the pad stone; T400, hoist the box beam and let it slowly fall on the adjusting jack of the cap beam on the first beam erection side of the TY pier. At the same time, continuously raise the sand bucket on the winch on the rear beam erection side to increase the counterweight until the box beam on the first beam erection side completely falls on the adjusting jack; T500, hoist the box beam and let it slowly fall on the adjusting jack of the cap beam on the rear beam side of the TY pier. At the same time, the winch on the rear beam side continuously lowers the sand bucket to reduce the counterweight until the box beam on the rear beam side completely falls on the adjusting jack; T600. Lower the sand bucket completely into the water, remove the sand bucket and dismantle the winch on the top of the TY pier.

10. A method for controlling eccentric load of TY piers during construction according to any one of claims 1 to 5, characterized in that: The specific operations are: G100: Reserve holes on the cap beam at the top of the TY pier, drive steel pipe columns in the water at the bottom of the bridge, and install multiple counterweight jacks on the steel pipe columns; G200, use steel strands to connect the top side of the TY pier to the counterweight jack through the reserved holes on the cap beam; G300, then set a cushion stone on the top of the cap beam, and set an adjusting jack next to the cushion stone. The counterweight jack is pulled back to the designed tension and then anchored as the initial counterweight; G400, hoist the box girder and let it slowly fall on the adjusting jack of the cap beam on the first beam erection side of the TY pier, and at the same time, continuously tighten the counterweight jack on the rear beam erection side to increase the counterweight until the box girder on the first beam erection side completely falls on the adjusting jack; G500, hoist the box beam and make it slowly fall on the adjustment jack of the cap beam on the rear beam side of the TY pier, and at the same time, keep the counterweight jack on the rear beam side to prevent it from loosening to reduce the counterweight until the box beam on the rear beam side completely falls on the adjustment jack; G600, completely loosen the counterweight jack, unload all the counterweight, and remove the counterweight jack and steel strand.

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