CN-122013890-A - Quick butt joint installation process of large-span steel structure for constructional engineering

Abstract

The invention discloses a rapid butt-joint installation process of a large-span steel structure for constructional engineering. The technology comprises the steps of placing a steel structure section to be butted on a flexible jig frame to obtain a folding gap, defining an active heat compensation area in a main stress component non-welding area which is at a preset axial distance from a welding line to be butted, heating the area in a controlled manner, pushing the butted end face to move relatively until the folding gap is closed by utilizing axial heat expansion displacement generated by the area, performing backing welding on the butted end face under a constant temperature state of keeping controlled compensation of the area, and dynamically adjusting the cooling rate of the active heat compensation area according to welding heat input parameters and a shrinkage prediction model in the welding line filling and covering stage, so that synchronous shrinkage of the area is used for counteracting or reducing shrinkage deformation of the welding line area. The invention eliminates the large mechanical stretching tool, realizes the micro-stress lamination of the butt joint end surfaces, obviously reduces the overall residual stress level and improves the fatigue resistance of the structure.

Inventors

• Rao Aimei

Assignees

• 江西亮业建设工程有限公司

Dates

Publication Date

20260512

Application Date

20260303

Claims (8)

1. 1. The rapid butt joint installation process of the large-span steel structure for the constructional engineering is characterized by comprising the following steps of: s1, placing a steel structure section to be butted on a flexible jig frame, keeping a natural in-place state, and obtaining a closing gap measurement value between butted end surfaces; s2, defining an active thermal compensation zone in a main stress component non-welding zone which is at a preset axial distance from a weld joint to be butted; S3, heating the active thermal compensation area in a controlled manner to enable the active thermal compensation area to generate axial thermal expansion displacement so as to push the butt end surfaces to move relatively until the folding gap is closed; S4, under the condition that the active thermal compensation area is kept in a controlled compensation state, root bottoming welding is conducted on the butt end face; S5, dynamically adjusting the cooling rate of the active thermal compensation area in the welding seam filling and capping welding stage, so that the synchronous shrinkage of the active thermal compensation area in the time dimension is used for counteracting or reducing the welding shrinkage of the butt joint end surfaces, and the integral residual stress of the structure is effectively restrained.
2. 2. The rapid butt-joint installation process of a large-span steel structure for constructional engineering according to claim 1, wherein the rapid butt-joint installation process comprises the following steps of: in the step S2, the range of the preset axial distance is defined as that the axial distance of the member is 1.5m to 5.0m from the butt welding seam to be welded, and the highest temperature for heating the active heat compensation zone is defined as being lower than the metallographic phase transition temperature of the large-span steel structure base material.
3. 3. The rapid butt-joint installation process of a large-span steel structure for constructional engineering according to claim 1, wherein the rapid butt-joint installation process comprises the following steps of: In step S3, the control unit determines a target temperature rise based on the measured value of the closing gap, the linear expansion coefficient of the main stress member, and the length of the active thermal compensation region; And the control unit takes the target temperature rise as a reference, and dynamically adjusts the heating power by combining a real-time displacement feedback signal until the gap is completely closed and then the heating state is locked.
4. 4. A construction engineering large span steel structure quick butt joint installation process according to claim 3, characterized in that: in the steps S1 and S3, an external bridging displacement sensor is adopted to acquire the folding gap measurement value and a real-time displacement feedback signal; The external bridging displacement sensor is installed in such a way that a main body box is installed on the outer surface of a steel structure on one side of a butt joint end face, a fixed anchor point or a reflecting target is installed on the outer surface of the steel structure on the other side of the butt joint end face, and a measuring connecting line or an optical path spans from the outside of the folding gap so as to avoid physical interference of the sensor when the folding gap is closed.
5. 5. The rapid butt-joint installation process of a large-span steel structure for constructional engineering according to claim 1, wherein the rapid butt-joint installation process comprises the following steps of: In step S5, a control unit is adopted to dynamically adjust the cooling rate of the active thermal compensation area according to the welding heat input parameters and a preset weld shrinkage prediction model.
6. 6. The rapid butt-joint installation process of the large-span steel structure for the constructional engineering, which is characterized in that: The specific logic of the control unit for dynamically adjusting the cooling rate is as follows: Collecting welding speed, welding current and welding voltage parameters of a current layer channel in real time to calculate dynamic line energy input, substituting the dynamic line energy input into the weld shrinkage prediction model by combining the thickness of the steel plate and the joint constraint degree, and outputting an expected shrinkage curve in the cooling process of the current layer channel; And adjusting the heating output power of the active thermal compensation area according to the heating output power, so that the cooling shrinkage curve of the active thermal compensation area is dynamically matched with the expected shrinkage curve.
7. 7. A quick docking installation system for a long span steel structure for implementing the process of any one of claims 1 to 6, comprising: The flexible jig frame is arranged at the bottom of the steel structure section to be butted and is used for providing the freedom degree of axial sliding of the steel structure; the heating device is wrapped and arranged on the outer side of the main stress component of the active thermal compensation zone; the displacement sensor is connected with the butt end surface in a bridging way and is used for acquiring the closing gap measurement value and a real-time displacement feedback signal; and the control unit is respectively in communication connection with the heating device and the displacement sensor, and is configured to control the output power of the heating device based on the folding gap measured value so as to drive the butt end face to be closed and maintain a controlled compensation state in a subsequent welding stage.
8. 8. The large span steel structure quick docking mounting system as recited in claim 7, wherein: the heating device is a flexible electromagnetic induction heating blanket or a heating coil; The system also comprises a temperature sensor arranged on the surface of the active thermal compensation zone, and the temperature sensor is in communication connection with the control unit and is used for providing a real-time temperature feedback signal.

Description

Quick butt joint installation process of large-span steel structure for constructional engineering Technical Field The invention relates to the technical field of constructional engineering and bridge construction, in particular to a rapid butt joint installation process of a large-span steel structure. Background In the aerial butt joint and closure links of large-span steel structures such as large-span roofs, trusses and steel box girder bridges, a closure gap is usually formed between end faces to be butted due to factors such as manufacturing errors, environmental temperature fluctuation, structure dead weight downwarping and the like. In the prior art, temperature variations and heat input are generally considered to be negative factors leading to structural deformations and residual stresses. Therefore, the conventional process generally avoids introducing heat in the non-welding area, and usually adopts mechanical means such as a large hydraulic jack, a chain block or a clamping code to forcedly perform cold stretching or cold propping so as to eliminate the folding gap. However, the tensile forces generated by mechanical means can seal the initial assembly stresses within the structure. In addition, in the process of welding a folding seam, the local high-temperature molten pool is cooled to generate volume shrinkage, and welding residual stress is generated. After the two stresses are superposed, the deflection of the structure after the support is unloaded can be sunk, or fatigue cracking can be caused in long-term service. Meanwhile, large mechanical tools have inconvenient operation and potential safety hazards in high-altitude operation. Disclosure of Invention The invention aims to solve the technical problems of reducing mechanical assembly stress in the folding process of a large-span steel structure and inhibiting shrinkage stress generated in the welding stage, thereby improving the butt joint precision and reducing the residual stress level. The technical aim of the invention is realized by the following technical scheme that the rapid butt joint installation process of the large-span steel structure for the constructional engineering comprises the following steps: s1, placing a steel structure section to be butted on a flexible jig frame, keeping a natural in-place state, and obtaining a closing gap measurement value between butted end surfaces; s2, defining an active thermal compensation zone in a main stress component non-welding zone which is at a preset axial distance from a weld joint to be butted; S3, heating the active thermal compensation area in a controlled manner to enable the active thermal compensation area to generate axial thermal expansion displacement so as to push the butt end surfaces to move relatively until the folding gap is closed; S4, under the condition that the active thermal compensation area is kept in a controlled compensation state, root bottoming welding is conducted on the butt end face; S5, dynamically adjusting the cooling rate of the active thermal compensation area in the welding seam filling and capping welding stage, so that the synchronous shrinkage of the active thermal compensation area in the time dimension is used for counteracting or reducing the welding shrinkage of the butt joint end surfaces, and the integral residual stress of the structure is effectively restrained. Further, in step S2, the range of the preset axial distance is defined as 1.5m to 5.0m of the to-be-butt welded seam along the axial distance of the component, and the highest temperature for heating the active thermal compensation zone is defined as being lower than the metallographic phase transition temperature of the large-span steel structure base material. Further, in step S3, the control unit determines a target temperature rise based on the measured value of the closing gap, the linear expansion coefficient of the main stress member, and the length of the active thermal compensation zone; And the control unit takes the target temperature rise as a reference, and dynamically adjusts the heating power by combining a real-time displacement feedback signal until the gap is completely closed and then the heating state is locked. Further, in the steps S1 and S3, an external bridge-type displacement sensor is adopted to obtain the measurement value of the folding gap and a real-time displacement feedback signal; The external bridging displacement sensor is installed in such a way that a main body box is installed on the outer surface of a steel structure on one side of a butt joint end face, a fixed anchor point or a reflecting target is installed on the outer surface of the steel structure on the other side of the butt joint end face, and a measuring connecting line or an optical path spans from the outside of the folding gap so as to avoid physical interference of the sensor when the folding gap is closed. Further, in step S5, a control unit is adopted to dynamically adjust