A method for determining reduction coefficient and a design method for bracket structure

Abstract

The present invention relates to a method for determining reduction coefficients and a design method for a bracket structure. A method for determining reduction coefficients is used to determine the reduction coefficients for the transfer of concrete loads to the bracket during the layered pouring of the 0# block concrete. The maximum stress and maximum deflection in the concrete pouring process of the (i + 1)-th layer are obtained through finite element simulation. By conducting pouring tests and monitoring the stress and deflection of the bracket, the stress increment Δσ max，i+1 and deflection increment Δω max，i+1 from the formation of the i-th layer of concrete to the concrete pouring process of the (i + 1)-th layer are obtained. Then, stress change calculations are performed to obtain the stress reduction coefficient K i+1 for the (i + 1)-th layer, and deflection change calculations are performed to obtain the deflection reduction coefficient P i+1 for the (i + 1)-th layer. By taking the larger value between K i+1 and P i+1 as the reduction coefficient Q i+1 for the (i + 1)-th layer, and using Q i+1 as the reduction coefficient for the (i + 1)-th layer to design the bracket, it is possible to better reduce material waste while ensuring the design safety factor of the bracket.

Description

Technical Field

[0001] The present invention relates to the technical field of bracket structure design for layered pouring of 0# block concrete, and particularly to a method for determining reduction coefficient and a design method for bracket structure. Background Art

[0002] For the 0# block concrete of continuous beam bridges (rigid frame bridges, etc.), due to the large volume of concrete, it is usually necessary to carry out layered pouring. When designing the bracket structure, since the already poured concrete can participate in the structural force of the upper layer of concrete, the force transmitted to the bracket structure can be reduced to a certain extent, that is, the reduction coefficient of the concrete load transmitted to the bracket structure under the layered pouring of 0# block concrete. Problems existing in current research:

[0003] 1. There is little research on the reduction coefficient of concrete load. Most engineers rely on experience to reduce the load during design. For example, directly selecting a reduction coefficient of 0.5 for bracket design may make the bracket design too conservative, resulting in material waste, or the design safety factor is not enough, leading to inability to guarantee safety.

[0004] 2. When monitoring the bracket test, the layout of measuring points lacks theoretical guidance, which is likely to cause the measuring points not to be arranged at the most unfavorable positions, or although arranged at the most unfavorable positions, in most cases, this is the result of casting a wide net, resulting in too high test costs.

[0005] 3. The test monitoring means are backward. Currently, conventional monitoring techniques are still used. By pasting strain gauges (gages) and arranging dial gauges (displacement gauges) to obtain the response values of the structure, real-time monitoring and early warning cannot be carried out through this method, resulting in high labor cost input and cumbersome later data processing. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for determining reduction coefficient and a design method for bracket structure aiming at the problems that for the 0# block concrete, layered pouring is usually required, and when designing the bracket for 0# block concrete, most engineers rely on experience to reduce the load, which may make the bracket design too conservative, resulting in material waste, or the design safety factor is not enough, leading to inability to guarantee safety. This method can obtain a more accurate reduction coefficient, so as to better reduce material waste on the premise of ensuring the design safety factor of the bracket.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0008] A method for determining reduction coefficient, used for determining the reduction coefficient of concrete load transmitted to the bracket under the layered pouring of 0# block concrete, including the step of obtaining the reduction coefficient Q of the (i + 1)-th layer i+1 :

[0009] S1. Obtain the maximum stress Y of the bracket during the pouring of the (i + 1)-th layer of concrete for the 0# block concrete based on finite element simulation max，i+1 and the maximum deflection X max，i+1 ; conduct a layered pouring test on the 0# block concrete, and obtain the maximum stress σ’ of the bracket after the i-th layer of concrete is formed through monitoring max，i and the maximum displacement ω’ max，i , and obtain the maximum stress σ of the bracket during the pouring of the (i + 1)-th layer of concrete through monitoring max，i+1 and the maximum displacement ω max , i+1 ; then obtain the stress increment Δσ max，i+1 and the deflection increment Δω max of the bracket after the (i + 1)-th layer of concrete is poured, i+1 , where, Δσ max，i+1 = σ max，i+1 - σ’ max，i , Δω max，i+1 = ω max，i+1 - ω’ max，i ;

[0010] S2. Obtain the stress reduction coefficient K i+1 and the deflection reduction coefficient P i+1 of the (i + 1)-th layer, where, K i+1 = Δσ max , i+1 / Y max，i+1 , P i+1 = Δω max，i+1 / X max，i+1 , take the larger value of P i+1 and K i+1 as the reduction coefficient Q of the (i + 1)-th layer i+1 .

[0011] In this solution, the reduction coefficient refers to the reduction coefficient of the concrete load transmitted to the bracket under the layered pouring of the 0# block concrete. The number of layers of the 0# block concrete is related to the height of the 0# block concrete, but generally it is divided into two or three layers. The layering of the 0# block concrete in the finite element simulation of this solution should be consistent with that of the experimental 0# block concrete. The first layer of concrete is poured on the bracket, and generally the reduction coefficient is not considered; the second layer of concrete is poured on the top surface after the first layer of concrete is formed. After the first layer of concrete is formed, it can be used as the bearing structure during the pouring of the second layer of concrete. Therefore, there is a reduction in the concrete load transmitted to the bracket during the pouring of the second layer of concrete; correspondingly, there is also a reduction in the concrete load transmitted to the bracket during the pouring of the third layer of concrete. After the concrete is formed, it means that the concrete strength reaches the preset strength that can be used for the pouring of the next layer. Monitoring can be carried out by setting strain gauges and displacement gauges on the bracket, corresponding to stress monitoring and displacement monitoring respectively.

[0012] Ymax，i+1 It refers to the maximum stress of the bracket in the pouring process of the (i + 1)-th single-layer concrete of the 0# block concrete obtained based on finite element simulation, X max，i+1 It refers to the maximum deflection of the bracket in the pouring process of the (i + 1)-th single-layer concrete of the 0# block concrete obtained based on finite element simulation. In this method, the maximum stress and maximum deflection in the concrete pouring process of the (i + 1)-th layer of the 0# block concrete are obtained through finite element simulation. By conducting pouring tests and monitoring the stress and deflection of the bracket, the stress increment Δσ max，i+1 and deflection increment Δω max，i+1 from the formation of the i-th layer of concrete to the pouring process of the (i + 1)-th layer of concrete are obtained. Then, based on the increment Δσ max，i+1 of the monitored maximum stress and the maximum stress obtained from finite element simulation, the stress change calculation is carried out to obtain the stress reduction coefficient K i+1 of the (i + 1)-th layer. And based on the deflection increment Δω max，i+1 of the monitored and the maximum deflection obtained from finite element simulation, the deflection change calculation is carried out to obtain the deflection reduction coefficient P i+1 of the (i + 1)-th layer. K i+1 and P i+1 are both the ratios of the actual increment to the theoretical calculation, and both can more accurately reflect the reduction of the load of the (i + 1)-th layer of concrete transferred to the bracket. The accuracy of the reduction coefficient is higher, enabling better design of the bracket through the reduction coefficient. And K i+1 and P i+1 are in the relationship of increasing or decreasing simultaneously. By taking the larger value between K i+1 and P i+1 as the reduction coefficient Q i+1 of the (i + 1)-th layer, and using Q i+1 as the reduction coefficient of the (i + 1)-th layer to design the bracket, the bracket structure is made safer, and thus, on the premise of ensuring the design safety factor of the bracket, better reduction of material waste can be achieved.

[0013] Preferably, it further includes step S3. Repeat steps S1 - S2 multiple times to obtain the reduction coefficient Q i+1 of the (i + 1)-th layer in n tests, and take the maximum value among the reduction coefficients Q i+1 of the (i + 1)-th layer in n tests as the design reduction coefficient Q max，i+1 of the (i + 1)-th layer.

[0014] n is a positive integer. Through n tests, n reduction coefficients Q i+1 of the (i + 1)-th layer are obtained, and then the maximum value among the n reduction coefficients Q i+1 is taken as the design reduction coefficient Q max，i+1, it is more conducive to ensuring the design safety factor of the bracket. The number of layers of the 0# block concrete poured in the nth test needs to be the same, but the height and layer height of the 0# block concrete poured in each test are inconsistent, which will not affect the value of the design reduction coefficient Q of the (i + 1)th layer. max，i+1 The value obtained.

[0015] Preferably, when i = 2:

[0016] In step S1, based on finite element simulation, obtain the maximum stress Y of the bracket during the pouring of the second layer of concrete of the 0# block max，2 and the maximum deflection X max，2 , based on finite element simulation, obtain the maximum stress Y of the bracket during the pouring of the third layer of concrete of the 0# block max，3 and the maximum deflection X max，3 ; conduct a layered pouring test of the 0# block concrete, and obtain the maximum stress σ' max，1 and the maximum displacement ω' max，1 of the bracket after the first layer of concrete is formed through monitoring, and obtain the maximum stress σ max，2 and the maximum displacement ω max，2 of the bracket during the pouring of the second layer of concrete through monitoring, and obtain the maximum stress σ' max，2 and the maximum displacement ω' max，2 of the bracket after the second layer of concrete is formed through monitoring, and obtain the maximum stress σ max，3 and the maximum displacement ω max，3 of the bracket during the pouring of the third layer of concrete through monitoring; then obtain the stress increment Δσ max，2 and the deflection increment Δω max，2 of the bracket after the second layer of concrete is poured, and obtain the stress increment Δσ max，3 and the deflection increment Δω max，3 of the bracket after the third layer of concrete is poured, where Δσ max，2 = σ max，2 - σ' max，1 , Δω max，2 = ω max , 2 - ω' max，1 , Δσ max，3 = σ max，3 - σ' max，2 , Δω max，3 = ω max，3 - ω' max，2 ;

[0017] In step S2, obtain the stress reduction coefficient K 2 and the deflection reduction coefficient P 2 , where K 2 = Δσ max，2 / Ymax，2 , P 2 = Δω max，2 / X max，2 , take the larger value of P 2 and K 2 as the reduction coefficient Q of the second layer 2 ; obtain the stress reduction coefficient K of the third layer 3 and the deflection reduction coefficient P 3 , where K 3 = Δσ max , 3 / Y max，3 , P 3 = Δω max，3 / X max，3 , take the larger value of P 3 and K 3 as the reduction coefficient Q of the third layer 3 .

[0018] Since the 0# block concrete is generally poured in 2 - 3 layers, it is necessary to obtain the reduction coefficient of the second layer and the reduction coefficient of the third layer. Through the above method, during the three - layer pouring process of the 0# block concrete from bottom to top during the test, the Q 2 of the second layer and the reduction coefficient Q 3 of the third layer can be obtained simultaneously, which can reduce the number of tests.

[0019] Further preferably, it further includes step S3. Repeat steps S1 - S2 multiple times to obtain the reduction coefficient Q 2 of the second layer and the reduction coefficient Q 3 of the third layer in n tests. Take the maximum value of the reduction coefficient Q 2 of the second layer in n tests as the design reduction coefficient Q max，2 of the second layer, and take the maximum value of the reduction coefficient Q 3 of the third layer in n tests as the design reduction coefficient Q max，3 of the third layer.

[0020] Through the above solution, the design reduction coefficient Q max，2 of the second layer and the design reduction coefficient Q max，3 of the third layer can be obtained simultaneously. Compared with Q 2 and Q 3 , the design reduction coefficient Q max，2 and the design reduction coefficient Q max，3 have higher accuracy.

[0021] Preferably, before conducting the 0# block concrete layered pouring test in step S1, first set the strain gauge at the most unfavorable stress point of the bracket and set the displacement gauge at the most unfavorable deflection point of the bracket;

[0022] The method for obtaining the most unfavorable stress point of the bracket is as follows: Determine the position of the most unfavorable section of the bracket according to the principles of structural mechanics to obtain the most unfavorable section A, and then use midas civil to model and quickly obtain the most unfavorable section B of the bracket based on the position of the most unfavorable section A; if the positions of the most unfavorable section B and the most unfavorable section A on the bracket do not coincide, check and adjust the midas civil model, and re-compare the positions of the most unfavorable section B and the most unfavorable section A on the bracket until the positions of the most unfavorable section B and the most unfavorable section A on the bracket coincide; if the positions of the most unfavorable section B and the most unfavorable section A on the bracket coincide, select the position where the difference between the stress value and the stress limit value is the smallest on the most unfavorable section B as the specific position of the most unfavorable stress point of the bracket.

[0023] The method for obtaining the most unfavorable deflection point of the bracket is as follows: Use midas civil to model and calculate, and obtain the position where the maximum deflection value is located as the specific position of the most unfavorable deflection point of the bracket.

[0024] The most unfavorable stress point is the position where the absolute value of the difference between the component stress response value of the bracket under the action of the load and its stress limit value is the smallest, which means that the stress is more likely to reach the preset limit, and the stress includes bending stress and shear force; the most unfavorable deflection point is the position where the absolute value of the difference between the component deflection response value of the bracket under the action of the load and its deflection limit value is the smallest, which means that the deflection is more likely to reach the preset limit, and can be directly reflected by the maximum deflection value. By setting strain gauges at the most unfavorable stress point of the bracket and displacement gauges at the most unfavorable deflection point, the most unfavorable response value of the bracket can be better reflected, which is beneficial to obtaining the corresponding reduction coefficients more accurately through stress and deflection respectively. And by comparing the stress reduction coefficient calculated from the stress change and the deflection reduction coefficient calculated from the deflection change, and taking the maximum value, even if a certain value between the two becomes smaller due to the reduced force at the most unfavorable point corresponding to the upward layered pouring process, the error can be reduced by the other value, so that the reduction coefficient of this layer of concrete can be obtained more accurately.

[0025] Through the principle of structural mechanics, the force analysis diagram of the bracket can be obtained. Then, based on the position where the difference between the stress value and the stress limit value in the force analysis diagram is the smallest, the location of the most unfavorable section can be initially judged to obtain the most unfavorable section A. According to the position of the most unfavorable section A, the most unfavorable section B can be found more quickly in the midas civil model. Compare the most unfavorable section A in the force analysis with the most unfavorable section B in the midas civil model. If the positions do not coincide, there is an error in the midas civil model, and it needs to be checked and adjusted until the positions of the most unfavorable section A and the most unfavorable section B coincide to determine the accuracy of the midas civil model. On the premise of determining the accuracy of the midas civil model, find the position where the difference between the stress value and the stress limit value is the smallest on the most unfavorable section B, which is the specific position of the most unfavorable stress point of the bracket. And through the above method, the most unfavorable stress point and the most unfavorable deflection point of the bracket can be determined more accurately, which can avoid blindly arranging measuring points and failing to monitor the most unfavorable response value of the structure, and can also avoid arranging a large number of measuring points and causing too high test costs.

[0026] Preferably, a stress monitoring system is used to monitor the maximum stress of the bracket. The stress monitoring system includes a strain gauge, a data transmission module, and a cloud platform automatic monitoring module. The strain gauge is used to collect stress values, the data transmission module is used to transmit the stress value data collected by the strain gauge to the cloud platform automatic monitoring module, and the cloud platform automatic monitoring module is used to monitor the maximum stress.

[0027] Traditional stress monitoring methods require a large amount of manpower and have a low automation level, resulting in high safety risks, and the monitoring efficiency and effect are not ideal. Through the above stress monitoring system, the stress of the bracket can be monitored, transmitted, and processed in real time. It requires less manpower, is more convenient and fast to process, has low safety risks, high monitoring efficiency, and better monitoring effects.

[0028] Preferably, a displacement monitoring system is used to monitor the maximum displacement of the bracket. The displacement monitoring system includes a displacement meter, a data transmission module, and a cloud platform automatic monitoring module. The displacement meter is used to collect displacement values, the data transmission module is used to transmit the displacement value data collected by the displacement meter to the cloud platform automatic monitoring module, and the cloud platform automatic monitoring module is used to monitor the maximum displacement.

[0029] Traditional displacement monitoring methods require a large amount of manpower and have a low automation level, resulting in high safety risks, and the monitoring efficiency and effect are not ideal. Through the above displacement monitoring system, the displacement of the bracket can be monitored, transmitted, and processed in real time. It requires less manpower, is more convenient and fast to process, has low safety risks, high monitoring efficiency, and better monitoring effects.

[0030] Preferably, the stress monitoring system and the displacement monitoring system adopt the same set of data transmission modules and cloud platform automatic monitoring modules, which increases resource utilization rate and reduces costs.

[0031] Preferably, the strain gauges and displacement gauges are both arranged at the transverse middle of the lower flange plate at the mid-span of the main longitudinal beam corresponding to the bottom of the 0# block concrete web.

[0032] Since the 0# block concrete has webs on both sides, during the web pouring process, the stress is the greatest on both sides. The strain gauges and displacement gauges are both arranged at the corresponding members at the bottom of the web during the layered pouring of the concrete. The mechanical property response value of the members here changes greatly, which can better monitor the stress response value and deflection response value of the bracket during the entire pouring process of the 0# block concrete, and is beneficial to conveniently and accurately obtain the load reduction coefficient for each layer of concrete pouring.

[0033] A design method for a bracket structure is used for the design of the bracket for the layered pouring of the 0# block concrete, and the bracket is designed by using the reduction coefficient obtained by the reduction coefficient determination method described in any one of the above or the design reduction coefficient.

[0034] Through the above reduction coefficient determination method, the reduction coefficient or design reduction coefficient corresponding to the calculation of each layer of the 0# block concrete can be obtained more accurately, making the designed bracket safer. Furthermore, on the premise of ensuring the design safety factor of the bracket, the waste of materials can be better reduced; and the bracket designed by the more accurate reduction coefficient or design reduction coefficient is safer and more conducive to the pouring of the 0# block concrete.

[0035] Preferably, when the height of the 0# block concrete is greater than or equal to 6m, the 0# block concrete is poured in three layers, and the reduction calculation of the load transferred from the second layer of concrete to the bracket is carried out by using the design reduction coefficient Q max，2 for calculation, and the reduction calculation of the load transferred from the third layer of concrete to the bracket is carried out by using the design reduction coefficient Q max，3 for calculation;

[0036] When the height of the 0# block concrete is less than 6m, the 0# block concrete is poured in two layers, and the reduction calculation of the load transferred from the second layer of concrete to the bracket is carried out by using the design reduction coefficient Q max，2 for calculation.

[0037] The design reduction coefficient Q max，2 is the reduction coefficient of the second layer obtained by testing and calculating during the three-layer pouring process of the 0# block concrete, and the design reduction coefficient Q max，3 is the reduction coefficient of the third layer obtained by testing and calculating during the three-layer pouring process of the 0# block concrete.

[0038] When the height of the 0# block concrete is greater than or equal to 6m, it is generally poured in three layers. When the height of the 0# block concrete is less than 6m, it is generally poured in two layers. When the 0# block concrete is poured in two layers, the reduction coefficient of the second layer located above corresponds better to the reduction coefficient of the second layer when the 0# block concrete is poured in three layers. Therefore, when calculating the reduction of the second layer of the 0# block concrete poured in two layers, the design reduction coefficient Q obtained from the test and calculation of the three-layer pouring process of the 0# block concrete is used for calculation, which is more accurate. max，2 For calculation, it is more accurate.

[0039] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0040] 1. The reduction coefficient determination method of the present invention obtains the maximum stress and maximum deflection of the concrete pouring link of the (i + 1)-th layer of the 0# block concrete through finite element simulation. By conducting pouring tests and monitoring the stress and deflection of the bracket, the stress increment Δσ max，i+1 and deflection increment Δω max，i+1 from the formation of the i-th layer of concrete to the pouring link of the (i + 1)-th layer of concrete are obtained. Then, based on the increment Δσ max，i+1 of the monitored maximum stress and the maximum stress obtained from finite element simulation, the stress change is calculated to obtain the stress reduction coefficient K i+1 of the (i + 1)-th layer. And based on the monitored deflection increment Δω max，i+1 and the maximum deflection obtained from finite element simulation, the deflection change is calculated to obtain the deflection reduction coefficient P i+1 of the (i + 1)-th layer. Both K i+1 and P i+1 can more accurately reflect the reduction of the load of the (i + 1)-th layer of concrete transmitted to the bracket, and the accuracy of the reduction coefficient is higher, enabling the bracket to be better designed through the reduction coefficient. By taking the larger value between K i+1 and P i+1 as the reduction coefficient Q i+1 of the (i + 1)-th layer, and using Q i+1 as the reduction coefficient of the (i + 1)-th layer to design the bracket, the bracket is made safer, and thus, on the premise of ensuring the design safety factor of the bracket, the waste of materials can be better reduced.

[0041] 2. The design method of the bracket structure of the present invention can obtain more accurate reduction coefficients or design reduction coefficients corresponding to the calculations of each layer of the 0# block concrete through the above reduction coefficient determination method, making the designed bracket safer. Thus, on the premise of ensuring the design safety factor of the bracket, the waste of materials can be better reduced; and the bracket designed with more accurate reduction coefficients or design reduction coefficients is safer and more conducive to the pouring of the 0# block concrete. Description of the Drawings

[0042] Figure 1(a) is a schematic diagram of the first layer of the 0# block concrete after forming in Example 1;

[0043] Figure 1(b) is a side view of the first layer of the 0# block concrete after forming in Example 1;

[0044] Figure 2(a) is a schematic diagram of the second layer of the 0# block concrete after forming in Example 1;

[0045] Figure 2(b) is a side view of the second layer of the 0# block concrete after forming in Example 1;

[0046] Figure 3(a) is a schematic diagram of the third layer of the 0# block concrete after forming in Example 1;

[0047] Figure 3(b) is a side view of the third layer of the 0# block concrete after forming in Example 1;

[0048] Figure 4 is the first theoretical stress analysis diagram of the most unfavorable stress measurement point in Example 1;

[0049] Figure 5 is the second theoretical stress analysis diagram of the most unfavorable stress measurement point in Example 1;

[0050] Figure 6 is the first schematic diagram of the installation state of the bracket on the pier column in Example 1;

[0051] Figure 7 is the strain gauge at Figure 6 the schematic diagram of the layout position of the most unfavorable stress point at the B-B cross-section in;

[0052] Figure 8 is the second schematic diagram of the installation state of the bracket on the pier column in Example 1;

[0053] Figure 9 is the displacement gauge at Figure 8 the schematic diagram of the layout position of the most unfavorable deflection point at the C-C cross-section in;

[0054] Figure 10 is the third schematic diagram of the installation state of the bracket on the pier column in Example 1;

[0055] Figure 11 is the schematic diagram of the strain gauge and displacement gauge arranged at the D-D cross-section at the mid-span of the main longitudinal beam.

[0056] Icon: 1 - strain gauge; 2 - displacement gauge; 3 - main longitudinal beam; 4 - diagonal brace; 5 - support; 6 - pier column; 7 - distribution beam. Specific embodiments

[0057] The present invention will be described in detail below with reference to the accompanying drawings.

[0058] To make the objectives, technical solutions and advantages of the present invention more clear and 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.

[0059] Embodiment 1

[0060] This embodiment provides a reduction coefficient determination method for determining the reduction coefficient of the concrete load transmitted to the bracket under the layered pouring of the 0# block concrete, including obtaining the reduction coefficient Q of the (i + 1)-th layer i+1 The steps are as follows:

[0061] S1. Based on finite element simulation, obtain the maximum stress Y of the bracket during the pouring of the (i + 1)-th layer of the 0# block concrete max，i+1 and the maximum deflection X max，i+1 ; conduct a layered pouring test of the 0# block concrete, and obtain the maximum stress σ' of the bracket after the formation of the i-th layer of concrete through monitoring max，i and the maximum displacement ω' max，i , and obtain the maximum stress σ of the bracket during the pouring of the (i + 1)-th layer of concrete through monitoring max，i+1 and the maximum displacement ω max , i+1 ; then obtain the stress increment Δσ max，i+1 and the deflection increment Δω max of the bracket after the pouring of the (i + 1)-th layer of concrete, where i+1 , Δσ max，i+1 = σ max，i+1 - σ' max，i , Δω max，i+1 = ω max，i+1 - ω' max，i ;

[0062] S2. Obtain the stress reduction coefficient K i+1 and the deflection reduction coefficient P i+1 of the (i + 1)-th layer, where i+1 , K max = Δσ i+1 / Y max，i+1 , P i+1 = Δω max，i+1 / X max，i+1 , and take the larger value of P i+1 and K i+1 as the reduction coefficient Q of the (i + 1)-th layer i+1 .

[0063] In this embodiment, the bracket can be the bracket disclosed in the Chinese patent application document with the publication number of CN113430945A. As shown in Figure 1(b), the bracket is installed on the pier 6 and includes a main longitudinal beam 3, a distribution beam 7, a bearing 5 and a diagonal brace 4 arranged along the longitudinal bridge direction.

[0064] The maximum stress Y max，i+1 and the maximum deflection X max，i+1 are both the finite element simulation results of the i+1th layer of single-layer concrete. In this solution, the reduction coefficient refers to the reduction coefficient of the concrete load transmitted to the bracket under the layered pouring of the 0# block concrete. The number of layers of the 0# block concrete is related to the height of the 0# block concrete, but generally it is divided into two or three layers. The layering of the 0# block concrete in the finite element simulation of this solution should be consistent with that in the test. As Figure 1(a)-1(b) shown, the first layer of concrete is poured on the bracket, and generally the reduction coefficient is not considered; as Figure 2(a)-2(b) shown, the second layer of concrete is poured on the top surface after the first layer of concrete is formed. After the first layer of concrete is formed, it can serve as the bearing structure for the pouring link of the second layer of concrete. Therefore, there is a reduction in the concrete load transmitted to the bracket during the pouring link of the second layer of concrete; correspondingly, as Figure 3(a)-3(b) shown, there is also a reduction in the concrete load transmitted to the bracket during the pouring link of the third layer of concrete. After the concrete is formed, it means that the concrete strength reaches the preset strength that can be used for the pouring of the next layer, such as 70% or more of the design strength. Monitoring can be carried out by setting a strain gauge 1 and a displacement gauge 2 on the bracket, corresponding to stress monitoring and displacement monitoring respectively. Existing monitoring methods can be used to manually collect stress data and displacement data.

[0065] Traditional stress monitoring methods require a large amount of human input and have a low level of automation, resulting in high safety risks and unsatisfactory monitoring efficiency and effectiveness. As a preferred implementation method, in step S1, a stress monitoring system is used to monitor the maximum stress of the bracket. The stress monitoring system includes a strain gauge 1, a data transmission module, and a cloud platform automatic monitoring module. The strain gauge 1 is used to collect stress values, the data transmission module is used to transmit the stress value data collected by the strain gauge 1 to the cloud platform automatic monitoring module, and the cloud platform automatic monitoring module is used to monitor the maximum stress. Through the above stress monitoring system, the stress of the bracket can be monitored, transmitted, and processed in real time. It requires less manpower, is more convenient and fast to process, has a low safety risk, high monitoring efficiency, and better monitoring effect. Optionally, in step S1, a displacement monitoring system is used to monitor the maximum displacement of the bracket. The displacement monitoring system includes a displacement gauge 2, a data transmission module, and a cloud platform automatic monitoring module. The displacement gauge 2 is used to collect displacement values, the data transmission module is used to transmit the displacement value data collected by the displacement gauge 2 to the cloud platform automatic monitoring module, and the cloud platform automatic monitoring module is used to monitor the maximum displacement. Through the above displacement monitoring system, the displacement of the bracket can be monitored, transmitted, and processed in real time. It requires less manpower, is more convenient and fast to process, has a low safety risk, high monitoring efficiency, and better monitoring effect. In addition, the stress monitoring system and the displacement monitoring system use the same set of data transmission module and cloud platform automatic monitoring module, which can increase resource utilization rate and reduce costs.

[0066] Before conducting the 0# block concrete layered pouring test in step S1, first set the strain gauge 1 at the most unfavorable stress point of the bracket and set the displacement gauge 2 at the most unfavorable deflection point of the bracket. The most unfavorable stress point is the position where the absolute value of the difference between the stress response value of the bracket component under the load and its stress limit value is the smallest, which means that the stress is more likely to reach the preset limit. The most unfavorable deflection point is the position where the absolute value of the difference between the deflection response value of the bracket component under the load and its deflection limit value is the smallest, which means that the deflection is more likely to reach the preset limit and can be directly reflected by the maximum deflection value. By setting the strain gauge 1 at the most unfavorable stress point of the bracket and the displacement gauge 2 at the most unfavorable deflection point, the most unfavorable response value of the bracket can be better reflected, which is beneficial to obtaining the corresponding reduction coefficients more accurately through stress and deflection respectively. And by comparing the stress reduction coefficient calculated from the stress change and the deflection reduction coefficient calculated from the deflection change and taking the maximum value, even if a certain value between the two becomes smaller due to the reduced force at the most unfavorable point corresponding to the upward layered pouring link, the error can be reduced by the other value, enabling a more accurate acquisition of the reduction coefficient of this layer of concrete.

[0067] The method for obtaining the most unfavorable stress point of the bracket can be: Through the principles of structural mechanics, the force analysis diagram of the bracket can be obtained, such as Figures 4-5, and then preliminarily determine the location of the most unfavorable section based on the position where the difference between the stress value and the stress limit value in the stress analysis diagram is the smallest, and obtain the most unfavorable section A. Figure 5 Among them, M 跨中 The stress at this position is the largest, which is the bending moment value, and the difference between it and the stress limit value is the smallest. Therefore, it can be determined that the cross-sectional area along the transverse bridge direction corresponding to the mid-span of the bracket is the most unfavorable section A. Then, use midas civil to model and quickly obtain the most unfavorable section B of the bracket based on the position of the most unfavorable section A, as shown in Figure 6 In the cross-section at B-B, that is, based on the position of the most unfavorable section A, the most unfavorable section B can be found more quickly in the midas civil model; compare the most unfavorable section A of the stress analysis with the most unfavorable section B of the midas civil model. If the positions of the most unfavorable section A and the most unfavorable section B on the bracket do not coincide, there is an error in the midas civil model, and it needs to be checked and adjusted until the positions of the most unfavorable section A and the most unfavorable section B on the bracket coincide to determine the accuracy of the midas civil model. On the premise of determining the accuracy of the midas civil model, that is, the positions of the most unfavorable section B and the most unfavorable section A on the bracket coincide, so find the position where the difference between the stress value and the stress limit value is the smallest on the most unfavorable section B, and select this position as the specific position of the most unfavorable stress point of the bracket, as shown in Figure 7 In the figure, according to the experiment, the installation position of strain gauge 1 is the specific position of the most unfavorable stress point.

[0068] The method for obtaining the most unfavorable deflection point of the bracket can be calculated by midas civil modeling, and the position where the maximum deflection value is obtained is the specific position of the most unfavorable deflection point of the bracket. Specifically, as shown in Figures 8-9 As shown, through this method, it can be obtained that the maximum deflection value is located at the mid-span position of the transverse distribution beam 7, that is, at the C-C cross-section, and the most unfavorable deflection point is Figure 9 The layout position of displacement gauge 2 in the figure, that is, at the middle of the bottom surface of the lower flange plate of the distribution beam 7.

[0069] Compared with the prior art, through the above method for determining the most unfavorable points, the most unfavorable stress point and the most unfavorable deflection point of the bracket can be determined more accurately, which can avoid blindly arranging measurement points and resulting in the inability to monitor the most unfavorable response value of the structure, and can also avoid arranging a large number of measurement points and causing too high test costs.

[0070] In addition to installing the strain gauge 1 at the most unfavorable stress point of the bracket and the displacement gauge 2 at the most unfavorable deflection point of the bracket to monitor stress and displacement respectively, since the 0# block concrete has webs on both sides and the stress is the greatest at both sides during the web pouring process, according to experiments and engineering experience, the strain gauge 1 and the displacement gauge 2 can also be installed at the corresponding members at the bottom of the web during the layered concrete pouring process, that is, on the main longitudinal beam 3 arranged along the longitudinal bridge direction. Specifically, the strain gauge 1 and the displacement gauge 2 are both installed at the transverse middle of the lower flange plate at the D-D cross-section at the mid-span of the main longitudinal beam 3 corresponding to the bottom of the 0# block concrete web, as Figures 10-11 shown, the strain gauge 1 and the displacement gauge 2 are installed at the middle of the lower flange plate at the mid-span of the main longitudinal beam 3. The mechanical property response value of the member here changes greatly, and it can also better monitor the stress response value and deflection response value of the bracket during the entire pouring process of the 0# block concrete, which is beneficial to conveniently and accurately obtain the load reduction coefficient of each layer of concrete pouring.

[0071] In this solution, i represents the number of layers, i is an integer greater than 0, and the (i + 1)-th layer represents the adjacent layer above the i-th layer. In this method, the maximum stress and maximum deflection during the concrete pouring process of the (i + 1)-th layer of the 0# block concrete are obtained through finite element simulation. By conducting pouring tests and monitoring the stress and deflection of the bracket, the stress increment Δσ max , i+1 and deflection increment Δω max，i+1 from the formation of the i-th layer of concrete to the concrete pouring process of the (i + 1)-th layer are obtained. Then, based on the increment Δσ max，i+1 of the monitored maximum stress and the maximum stress obtained by finite element simulation, the stress change is calculated to obtain the stress reduction coefficient K i+1 of the (i + 1)-th layer. And based on the monitored deflection increment Δω max，i+1 and the maximum deflection obtained by finite element simulation, the deflection change is calculated to obtain the deflection reduction coefficient P i+1 . Both K i+1 and P i+1 are the ratios of the actual increment to the theoretical calculation, and both can more accurately reflect the reduction of the load of the (i + 1)-th layer of concrete transmitted to the bracket. The accuracy of the reduction coefficient is higher, enabling better design of the bracket through the reduction coefficient. And K i+1 and P i+1 have the relationship of increasing and decreasing together. By taking the larger value between the two values of K i+1 and P i+1 as the reduction coefficient Q i+1 of the (i + 1)-th layer, and taking Q i+1Design the bracket using the reduction coefficient of the (i + 1)-th layer, making the bracket structure safer. Thus, on the premise of ensuring the design safety factor of the bracket, material waste can be better reduced. Finite element simulation is calculated using midas civil.

[0072] As a preferred implementation manner, it further includes step S3. Repeat steps S1 - S2 multiple times to obtain the reduction coefficient Q of the (i + 1)-th layer in n tests. i+1 , and take the maximum value of the reduction coefficient Q of the (i + 1)-th layer in n tests i+1 as the design reduction coefficient Q of the (i + 1)-th layer. max，i+1 .

[0073] n is a finite positive integer, and n can be 2, 3, 4, 5, etc. The test is a real casting, and the 0# block concrete required for pouring in the project is used as the test item. The bracket design of this project adopts the conventional design method to ensure safety. Through n tests, n reduction coefficients Q of the (i + 1)-th layer are obtained. i+1 , and then take the maximum value of the n reduction coefficients Q i+1 as the design reduction coefficient Q of the (i + 1)-th layer. max，i+1 , which is more conducive to ensuring the design safety factor of the bracket. The number of layers of the 0# block concrete poured in n tests needs to be the same, but the height and layer height of the 0# block concrete poured in each test being inconsistent will not affect the value of the design reduction coefficient Q of the (i + 1)-th layer. max，i+1 .

[0074] In this embodiment, taking the pouring of the 0# block concrete from bottom to top in three layers during the test as an example for illustration. Using the pouring of the 0# block concrete from bottom to top in three layers as the test can obtain the reduction coefficients of the second and third layers in one test. The specific steps are as follows:

[0075] That is, when i = 2:

[0076] In step S1, based on finite element simulation, obtain the maximum stress value Y of the bracket during the pouring of the second-layer concrete of the 0# block concrete max，2 and the maximum deflection value X max，2 , and based on finite element simulation, obtain the maximum stress value Y of the bracket during the pouring of the third-layer concrete of the 0# block concrete max，3 and the maximum deflection value X max，3 ; conduct a layered pouring test of the 0# block concrete, and obtain the maximum stress value σ’ max，1 and the maximum displacement value ω’ max，1 of the bracket after the first-layer concrete is formed through monitoring, and obtain the maximum stress value σ max，2 and the maximum displacement value ω max，2, obtain the maximum stress σ’ of the bracket after the second layer of concrete is formed through monitoring max，2 and the maximum displacement ω’ max，2 , obtain the maximum stress σ of the bracket during the pouring of the third layer of concrete through monitoring max，3 and the maximum displacement ω max，3 ; then obtain the stress increment Δσ max，2 and the deflection increment Δω max，2 of the bracket after the second layer of concrete is poured, and obtain the stress increment Δσ max，3 and the deflection increment Δω max，3 of the bracket after the third layer of concrete is poured. Among them, Δσ max，2 =σ max，2 -σ’ max，1 , Δω max，2 =ω max , 2 -ω’ max，1 , Δσ max，3 =σ max，3 -σ’ max，2 , Δω max，3 =ω max，3 -ω’ max，2 ;

[0077] The step S2. Obtain the stress reduction coefficient K 2 and the deflection reduction coefficient P 2 of the second layer, where K 2 =Δσ max , 2 / Y max , 2 , P 2 =Δω max , 2 / X max , 2 , take the larger value of P 2 and K 2 as the reduction coefficient Q 2 of the second layer; obtain the stress reduction coefficient K 3 and the deflection reduction coefficient P 3 of the third layer, where K 3 =Δσ max , 3 / Y max , 3 , P 3 =Δω max , 3 / X max , 3 , take the larger value of P 3 and K 3 as the reduction coefficient Q 3 of the third layer;

[0078] For example, the 0# block concrete is poured in three layers, and midas civil and on-site monitoring methods are used for calculation. The calculation results are shown in Table 1 in detail.

[0079] Table 1 Calculation Results of Reduction Coefficient

[0080]

[0081] Through calculation, it can be known that for the stress reduction coefficient and deflection reduction coefficient of the concrete load transferred to the bracket during the concrete pouring of the second layer, K 2 = 0.40 is obtained from stress calculation, and P 2 = 0.43 is obtained from deflection calculation. Taking the most unfavorable case Q 2 = max{K 2 , P 2} = max{0.40, 0.43} = 0.43; for the reduction coefficient of the concrete load transferred to the bracket during the concrete pouring of the third layer, K 3 = 0.18 is obtained from stress calculation, and P 3 = 0.20 is obtained from deflection calculation.

[0082] Taking the most unfavorable case Q 3 = max{K 3 , P 3} = max{0.18, 0.20} = 0.20.

[0083] Assume that the fluid line load of the second layer of concrete is Q 2 = 80 kN / m 2 , then the line load transferred to the bracket during the concrete pouring of the second layer is Q' 2 = q 2 ×Q 2 = 80×0.43 = 34.4 kN / m 2 ; the fluid line load of the third layer of concrete is Q 3 = 30 kN / m 2 , then the line load transferred to the bracket during the concrete pouring of the third layer is Q' 3 = q 3 ×Q 3 = 30×0.20 = 6.0 kN / m 2 .

[0084] When n tests are carried out, the step S3 needs to be executed, and steps S1 - S2 are repeated multiple times to obtain the reduction coefficient Q of the second layer and the reduction coefficient Q of the third layer in the n tests. Take the maximum value among the reduction coefficients Q of the second layer in the n tests as the design reduction coefficient Q of the second layer 2 and the reduction coefficient Q of the third layer 3 , take the maximum value among the reduction coefficients Q of the second layer in the n tests as the design reduction coefficient Q of the second layer 2 and the maximum value among the reduction coefficients Q of the third layer in the n tests as the design reduction coefficient Q of the third layer max，2, take the maximum value of the reduction coefficient Q of the third layer in n tests as the design reduction coefficient Q of the third layer 3 in it. And the linear load transmitted from the second-layer quasi-concrete pouring link to the bracket and the linear load transmitted from the third-layer quasi-concrete pouring link to the bracket should be calculated with the design reduction coefficient. max，3 . Since the layered pouring of the general 0# block concrete is 2 - 3 layers, it is necessary to obtain the reduction coefficient of the second layer and the reduction coefficient of the third layer. Through the above-mentioned method of pouring the 0# block concrete in three layers from bottom to top during the test, the design reduction coefficient Q of the second layer

[0085] and the design reduction coefficient Q of the third layer max，2 can be obtained simultaneously, which can reduce the number of tests. Of course, if the design reduction coefficient Q of the fourth layer max，3 is needed, the 0# block concrete during the test can also be poured in four layers from bottom to top. max，4

[0086] Example 2

[0087] This example provides a design method for a bracket structure, which is used for the design of the bracket for the layered pouring of 0# block concrete. The bracket is designed with the reduction coefficient or the design reduction coefficient obtained by the reduction coefficient determination method described in Example 1. The specific design of the bracket can adopt the design method of an assembled bracket disclosed in the Chinese patent application document with the publication number CN113430945A.

[0088] And when the height of the 0# block concrete is greater than or equal to 6m, the designed bracket is used for the three-layer pouring of the 0# block concrete. The reduction calculation of the load transmitted from the second-layer concrete to the bracket is carried out using the design reduction coefficient Q max，2 for calculation, and the reduction calculation of the load transmitted from the third-layer concrete to the bracket is carried out using the design reduction coefficient Q max，3 for calculation;

[0089] When the height of the 0# block concrete is less than 6m, the designed bracket is used for the two-layer pouring of the 0# block concrete. The reduction calculation of the load transmitted from the second-layer concrete to the bracket is carried out using the design reduction coefficient Q max，2 for calculation.

[0090] The design reduction coefficient Q max，2 is the reduction coefficient of the second layer obtained by testing and calculating during the three-layer pouring of the 0# block concrete, and the design reduction coefficient Q max，3 is the reduction coefficient of the third layer obtained by testing and calculating during the three-layer pouring of the 0# block concrete.

[0091] ​When the height of the 0# block concrete is greater than or equal to 6m, it is generally poured in three layers. When the height of the 0# block concrete is less than 6m, it is generally poured in two layers. When the 0# block concrete is poured in two layers, the reduction coefficient of the second layer located above corresponds better to the reduction coefficient of the second layer when the 0# block concrete is poured in three layers. Therefore, when calculating the reduction of the second layer of the 0# block concrete poured in two layers, the reduction coefficient Q of the second layer obtained from the test and calculation in the three-layer pouring process of the 0# block concrete is used for calculation, which is more accurate. max，2 Carry out the calculation, which is more accurate.

[0092] The design method of the bracket structure in this embodiment can obtain more accurate reduction coefficients corresponding to the calculation of each layer of the 0# block concrete through the reduction coefficient determination method in Embodiment 1, making the designed bracket safer. Furthermore, on the premise of ensuring the design safety factor of the bracket, it can better reduce the waste of materials; and the bracket designed with more accurate reduction coefficients or designed reduction coefficients is safer and more conducive to the pouring of the 0# block concrete.

[0093] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements 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 determining reduction coefficient, characterized in that, including the step of obtaining the reduction coefficient Q of the (i + 1)-th layer i+1 : S1. Obtain the maximum stress Y of the bracket of the (i + 1)-th layer of concrete in the 0# block during the pouring process based on finite element simulation max，i+1 and the maximum deflection X max，i+1 ; Conduct a layered pouring test on the 0# block concrete, and obtain the maximum stress σ’ of the bracket after the i-th layer of concrete is formed through monitoring max，i and the maximum displacement ω’ max，i , and obtain the maximum stress σ of the bracket during the pouring process of the (i + 1)-th layer of concrete through monitoring max，i+1 and the maximum displacement ω max，i+1 ; Then obtain the stress increment Δσ max，i+1 and the deflection increment Δω max，i+1 of the bracket after the (i + 1)-th layer of concrete is poured, where Δσ max，i+1 =σ max，i+1 -σ’ max，i , Δω max，i+1 =ω max，i+1 -ω’ max，i ; before the 0# block concrete layered pouring test in the step S1, strain gauges are first set at the most unfavorable stress points of the bracket, and displacement gauges are set at the most unfavorable deflection points of the bracket; The method for obtaining the most unfavorable stress points of the bracket is as follows: Determine the position of the most unfavorable section of the bracket according to the principle of structural mechanics to obtain the most unfavorable section A, then use midas civil to model and quickly obtain the most unfavorable section B of the bracket based on the position of the most unfavorable section A; if the positions of the most unfavorable section B and the most unfavorable section A on the bracket do not coincide, check and adjust the midas civil model, and re-compare the positions of the most unfavorable section B and the most unfavorable section A on the bracket until the positions of the most unfavorable section B and the most unfavorable section A on the bracket coincide; if the positions of the most unfavorable section B and the most unfavorable section A on the bracket coincide, then select the position where the stress value has the smallest difference from the stress limit value on the most unfavorable section B as the specific position of the most unfavorable stress point of the bracket; The method for obtaining the most unfavorable deflection point of the bracket is as follows: Use midas civil to model and calculate, and obtain the position where the maximum deflection value is located as the specific position of the most unfavorable deflection point of the bracket; S2. Obtain the stress reduction coefficient K of the (i + 1)-th layer i+1 and the deflection reduction coefficient P i+1 , where K i+1 = Δσ max，i+1 / Y max，i+1 , P i+1 = Δω max，i+1 / X max，i+1 . Take the larger value of P i+1 and K i+1 as the reduction coefficient Q of the (i + 1)-th layer i+1 ; Step S3. Repeat steps S1 - S2 multiple times to obtain the reduction coefficient Q of the (i + 1)-th layer in n trials i+1 , and take the reduction coefficient Q of the (i + 1)-th layer in n trials i+1 The maximum value among them is the design reduction coefficient Q of the (i + 1)-th layer max， i+1 .

2. The method for determining reduction coefficient according to claim 1, characterized in that, when i = 2: Step S1: Obtain the maximum stress value Y of the bracket during the pouring of the second layer of concrete in the 0# block based on finite element simulation max，2 and the maximum deflection value X max，2 , obtain the maximum stress value Y of the bracket during the pouring of the third layer of concrete in the 0# block based on finite element simulation max，3 and the maximum deflection value X max，3 ; conduct a layered pouring test on the 0# block concrete, and obtain the maximum stress value σ’ of the bracket after the first layer of concrete is formed through monitoring max，1 and the maximum displacement value ω’ max，1 , obtain the maximum stress value σ of the bracket during the pouring of the second layer of concrete through monitoring max，2 and the maximum displacement value ω max，2 , obtain the maximum stress value σ’ of the bracket after the second layer of concrete is formed through monitoring max，2 and the maximum displacement value ω’ max，2 , obtain the maximum stress value σ of the bracket during the pouring of the third layer of concrete through monitoring max，3 and the maximum displacement value ω max，3 ; then obtain the stress increment Δσ max，2 and the deflection increment Δω max，2 of the bracket after the second layer of concrete is poured, obtain the stress increment Δσ max，3 and the deflection increment Δω max，3 of the bracket after the third layer of concrete is poured, where, Δσ max，2 = σ max，2 - σ’ max，1 , Δω max，2 = ω max，2 - ω’ max，1 , Δσ max，3 = σ max，3 - σ’ max，2 , Δω max，3 = ω max，3 - ω’ max，2 ; Step S2. Obtain the stress reduction coefficient K of the second layer 2 and the deflection reduction coefficient P 2 , where K 2 =Δσ max，2 / Y max，2 , P 2 =Δω max，2 / X max，2 , take the larger value of P 2 and K 2 as the reduction coefficient Q of the second layer 2 ; Obtain the stress reduction coefficient K of the third layer 3 and the deflection reduction coefficient P 3 , where K 3 =Δσ max，3 / Y max，3 , P 3 =Δω max，3 / X max，3 , take the larger value of P 3 and K 3 as the reduction coefficient Q of the third layer 3 .

3. The method for determining reduction coefficient according to claim 2, characterized in that, It also includes step S3: repeating steps S1 - S2 multiple times to obtain the reduction coefficient Q of the second layer in n trials 2 and the reduction coefficient Q of the third layer 3 , and taking the maximum value among the reduction coefficients Q of the second layer in n trials 2 as the design reduction coefficient Q of the second layer max， 2 , and taking the maximum value among the reduction coefficients Q of the third layer in n trials 3 as the design reduction coefficient Q of the third layer max， 3 .

4. The method for determining reduction coefficient according to claim 3, characterized in that, A stress monitoring system is used to monitor the maximum stress of the bracket. The stress monitoring system includes strain gauges, a data transmission module, and a cloud platform automatic monitoring module. The strain gauges are used to collect stress values, the data transmission module is used to transmit the stress value data collected by the strain gauges to the cloud platform automatic monitoring module, and the cloud platform automatic monitoring module is used to monitor the maximum stress.

5. The method for determining reduction coefficient according to claim 4, characterized in that, The maximum displacement of the bracket is monitored through a displacement monitoring system. The displacement monitoring system includes displacement gauges, a data transmission module, and a cloud platform automatic monitoring module. The displacement gauges are used to collect displacement values, the data transmission module is used to transmit the displacement value data collected by the displacement gauges to the cloud platform automatic monitoring module, and the cloud platform automatic monitoring module is used to monitor the maximum displacement.

6. The method for determining reduction coefficient according to any one of claims 1-4, characterized in that, Both the strain gauges and the displacement gauges are set at the transverse middle of the lower flange plate at the mid-span of the main longitudinal beam corresponding to the bottom of the 0# block concrete web.

7. A design method for a bracket structure, characterized in that, The bracket is designed by using the design reduction coefficient obtained by the reduction coefficient determination method according to any one of claims 4-6.

8. The design method for the bracket structure according to claim 7, characterized in that, When the height of the 0# block concrete is greater than or equal to 6m, the 0# block concrete is poured in three layers. The reduction calculation of the load transferred by the second-layer concrete to the bracket is carried out using the design reduction coefficient Q max，2 for calculation, and the reduction calculation of the load transferred by the third-layer concrete to the bracket is carried out using the design reduction coefficient Q max，3 for calculation; When the height of the 0# block concrete is less than 6m, the 0# block concrete is poured in two layers, and the reduction calculation of the load transferred by the second-layer concrete to the bracket adopts the design reduction coefficient Q max，2 for calculation.

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