CN-121976464-A - Tensioning optimization control method for parallel steel strand stay ropes

CN121976464ACN 121976464 ACN121976464 ACN 121976464ACN-121976464-A

Abstract

The invention provides a parallel steel strand stay cable tensioning optimization control method which comprises the steps of firstly determining basic parameters and unstressed cable length of a stay cable, determining target tensioning control force of the stay cable of a current construction section and theoretical distance between a main beam anchor point and a bridge tower anchor point after tensioning is completed, solving the unstressed cable length of the stay cable by considering suspension cable sag effect and elastic elongation based on parabolic theory, secondly establishing a structure coupling effect-based adjacent strand tensioning force recurrence relation, namely simplifying a bridge tower and main beam structure system into a linear elastic system along the axis direction of the stay cable to obtain a nonlinear proportional relation between adjacent strand tensioning forces caused by flexible coupling effect of structural rigidity and a cable body, thirdly calculating single strand tensioning force theoretical values of the whole stay cable under target value control, and fourthly performing anchoring loss compensation and final tensioning force optimization, namely calculating each strand of accurate tensioning force of the whole stay cable to overstretch the whole stay cable so as to enable the whole stay cable force to be consistent with a design target.

Inventors

YAN GUOXIANG
WANG SIAN
ZHANG LEI
LI XINKUI
ZHONG YUNLONG
ZHOU XIANGYANG

Assignees

上海建工集团股份有限公司

Dates

Publication Date: 20260505
Application Date: 20251231

Claims (5)

1. The tension optimization control method for the parallel steel strand stay cable is characterized by comprising the following steps of: Step S1, basic parameters and the length of the stress-free cable of the stay cable are determined, namely, the target tensioning control force of the stay cable of the current construction section and the theoretical distance between a main beam anchor point and a bridge tower anchor point after tensioning are determined according to a bridge design drawing and simulation calculation analysis; S2, establishing a tensile force recurrence relation of adjacent strands based on a structural coupling effect, namely simplifying a bridge tower and a main girder structure system into a linear elastic system along the axial direction of a stay cable, wherein the rigidity of the linear elastic system is equivalent to the rigidity, and obtaining a nonlinear proportional relation between the tensile forces of the adjacent strands caused by the structural rigidity and the flexible coupling effect of a cable body; S3, calculating a theoretical value of single-strand tension of the whole stay cable under the control of a target value; And S4, anchor loss compensation and final tensioning force optimization, namely, calculating the accurate tensioning force of each strand of the whole stay cable to carry out overstretch so that the cable force of the whole stay cable is consistent with a design target and the stress of each strand of the steel strand is uniform in order to compensate the nonlinear prestress loss generated by the steel strand when the working clamping piece of the anchor device retracts during jacking and anchoring in the actual tensioning and anchoring process.
2. The control method according to claim 1, wherein in the step S1, the calculation formula of the stay cable unstressed cable length S 0 is: Wherein E is the elastic modulus of the stay cable steel strand, the unit is MPa, A is the cross-sectional area of the whole stay cable steel strand, the unit is m 2 , q is the unit weight of the stay cable steel strand, the unit is kN/m, and alpha is the included angle between the axis of the stay cable and the horizontal direction, and the unit is degree.
3. The control method according to claim 1, characterized in that in the step S2, the calculation formula of the equivalent stiffness Ke is: Wherein delta is the final theoretical displacement between the main beam anchor point and the bridge tower anchor point after the whole steel strand is tensioned, and the unit is m; based on the equivalent model, when the single strand is tensioned, after the i-th strand steel strand is tensioned, the force balance calculation formula of the system is as follows: K e ×δ i ＝i×F i (3), Similarly, after the i-1 strand steel strand is tensioned, the following steps are obtained: K e ×δ i-1 ＝(i-1)×F i-1 (4), Delta i 、δ i-1 in the formula is accumulated displacement between a main beam anchor point and a bridge tower anchor point after the tensioning of the ith strand and the (i-1) th strand of steel strands is completed, wherein the unit is m, F i 、F i-1 is the tensioning force of the ith strand and the (i-1) th strand of steel strands, the unit is KN, and the formula (1) is based on the fact that after the tensioning of the (i-1) th strand of steel strands is completed, the method comprises the following steps: Wherein L i-1 is the theoretical distance between main beam anchor points after the i-1 steel strand is stretched, A 0 is the cross-sectional area of a single steel strand, the unit is m 2 ,q 0 is the unit weight of the single steel strand, and the unit is KN/m; Similarly, after the tensioning of the ith steel strand is completed, the following steps are obtained: Wherein L i is the theoretical distance between the main beam anchor point and the bridge tower anchor point after the tensioning of the ith strand of steel strand, simultaneous equations (5) and (6) simplify approximate treatment on the premise of meeting engineering precision, and obtain: Wherein n is the total number of steel strands in a single stay cable, and in the process of tensioning the ith strand, the internal force of the tensioned ith-1 steel strand is attenuated from F i-1 to F i , and the change amount of the internal force causes the change amount of the cable length to be delta i -δ i-1 ＝L i-1 -L i , and the method can be obtained by the formula (7): Wherein the calculation formula of the influence factor beta is as follows: the recurrence relation between F i-1 、F i can be obtained by simultaneous formulas (3), (4), and (8) as follows:
4. A control method according to claim 3, wherein in said step S3, based on the formula (10), the pulling force F i of the steel strand required to be applied in pulling the ith strand is inversely recursively calculated from the final state i=n: Under ideal conditions, the whole stay cable force can reach the final target F according to the series tensioning of the formula (11).
5. The control method according to claim 4, wherein the correction is made to the formula (11), Obtaining the final actual tensioning control force Fi' of the ith steel strand: In the middle of The device is characterized in that the unit of the retraction amount of the working clamping piece is m, so that a control sequence { F 1 ′,F 2 ′,…,F i ′,…,F n-1 ′,F n ' } of the accurate tension force of each strand of the whole stay cable is obtained, and each strand of steel strand is loaded and anchored according to the sequence, namely, the force of the whole stay cable is consistent with a design target F.

Description

Tensioning optimization control method for parallel steel strand stay ropes Technical Field The invention belongs to the technical field of building construction, and particularly relates to a tensioning optimization control method for a parallel steel strand stay cable. Background The steel strand stay cable has become a mainstream cable form of a large-span cable-stayed bridge due to the economical efficiency and construction convenience. The system is formed by combining a plurality of high-strength low-relaxation steel strands, does not need factory prefabrication, and supports on-site flexible blanking and transportation. At present, the tensioning construction generally adopts a single tensioning mode to form a rope, and the core control method is mainly an equivalent tensioning method. However, the traditional method is based on the idealized assumption that the stress influence of each steel strand in an anchorage device is equal, but in the actual tensioning process, the factors such as deformation of a cable-stayed bridge structural system, interaction between the steel strands, slippage of the anchorage device and a clamping piece and the like all have obvious geometric nonlinearity and time-varying characteristics, so that the cable force of the pre-tensioned steel strand can be attenuated in a non-equivalent and nonlinear manner due to structural deformation caused by subsequent tensioning operation, and the cable force distribution deviation is caused, so that the uniformity of the cable force of each final strand of steel strand cannot be ensured. Therefore, how to provide an optimized control method for tensioning parallel steel strand stay cables is a technical problem that needs to be solved by the person skilled in the art. Disclosure of Invention The invention provides an optimization control method for tensioning parallel steel strand stay cables, which aims to overcome the inherent defect of an equivalent tensioning method in the existing single tensioning technology of the parallel steel strand stay cables and solve the problems of uneven cable force distribution, insufficient control precision and the like caused by ignoring multiple factors such as geometric nonlinearity of the stay cables, anchor retraction loss, coupling effect of a structural system and the like. A more accurate tension calculation formula and a control method are provided by fusing accurate finite element modeling, so that high precision and homogenization control of the cable force of the steel strand are realized, one-time tensioning is finally achieved, the problem of unequal attenuation of the cable force is effectively solved, the final tension of the whole cable is ensured to reach a design target, and the overall stress uniformity and service reliability of the stay cable are improved. The technical scheme of the tension optimization control method for the parallel steel strand stay cable is as follows: a tension optimization control method for a parallel steel strand stay cable comprises the following steps: Step S1, basic parameters and the length of the stress-free cable of the stay cable are determined, namely, the target tensioning control force of the stay cable of the current construction section and the theoretical distance between a main beam anchor point and a bridge tower anchor point after tensioning are determined according to a bridge design drawing and simulation calculation analysis; S2, establishing a tensile force recurrence relation of adjacent strands based on a structural coupling effect, namely simplifying a bridge tower and a main girder structure system into a linear elastic system along the axial direction of a stay cable, wherein the rigidity of the linear elastic system is equivalent to the rigidity, and obtaining a nonlinear proportional relation between the tensile forces of the adjacent strands caused by the structural rigidity and the flexible coupling effect of a cable body; Step S3, calculating a single-strand tension theoretical value of the whole stay cable under the control of a target value, and setting the final target of the whole stay cable in the tensioning process to be that after the nth strand (the last strand) of steel strands are tensioned and anchored, the force values of all the n strands of steel strands reach an ideal uniform state, namely F n =F/n; And S4, anchor loss compensation and final tensioning force optimization, namely, calculating the accurate tensioning force of each strand of the whole stay cable to carry out overstretch so that the cable force of the whole stay cable is consistent with a design target and the stress of each strand of the steel strand is uniform in order to compensate the nonlinear prestress loss generated by the steel strand when the working clamping piece of the anchor device retracts during jacking and anchoring in the actual tensioning and anchoring process. Further, in the step S1, the calculation formula of the stay cabl