A method of installing a ramp for a roll-on / roll-off ship

Abstract

The application discloses a method for installing a roll-on roll-off ship ramp, and steps are as follows: hoisting the ramp corresponding to a ship body foundation total section, performing three-dimensional positioning and calibration according to a design baseline and a rib position line, and then performing full-position welding to form a rigid installation reference; marking a hinge seat installation reference line, hoisting a ship body end hinge seat, and calibrating coaxiality, and then completing welding and fixation; hoisting the ramp body hinge, adjusting the level, and temporarily locking, hoisting the ramp cover, calibrating fitting precision, measuring the glue pressing amount, marking the relative installation reference, hoisting the movable deck to a temporary work station, avoiding the hoisting path of the upper total section, hoisting the upper total section, performing positioning and calibration, and then welding to form an upper structure, disassembling the ramp and the cover, cleaning the installation position, installing a glue pressing groove and a glue strip, resetting the two, and assembling electrical and outfitting parts. The method optimizes the process and operation time sequence, controls the installation precision in a closed loop, improves construction efficiency, reduces cost and construction risk, and has strong universality.

Description

Technical Field

[0001] This application relates to the technical field of ship cleaning, and more particularly to a method for installing a ramp for a roll-on / roll-off ship. Background Technology

[0002] Currently, the conventional installation method for roll-on / roll-off ramps in the industry involves first completing the full closure of the upper and lower hull sections, and then installing and matching the ramp body with the ramp cover. This method has many insurmountable technical drawbacks. Not only is the process logic reversed, requiring waiting for the upper section to be closed before core installation work can begin, resulting in a long rigid waiting period, a long overall construction cycle, and low construction efficiency, but it also suffers from insufficient control over installation precision. Ramp matching and adjustment must be carried out in a small, enclosed compartment, making it difficult to accurately control core parameters such as fit clearance and pressure application, which can easily lead to leaks. Faults such as seal failure and rotation jamming result in high rework costs and require the welding of numerous temporary lifting brackets, round pipe supports, and other auxiliary structures. This not only increases a lot of unnecessary work but also damages the hull material and the original anti-corrosion coating, posing long-term structural safety and corrosion risks. In addition, the frequent hot work after painting can easily damage the hull's formed anti-corrosion layer, and the anti-corrosion performance of the repainted areas cannot meet the overall painting standards, which will shorten the service life of the hull structure. Furthermore, the construction process overlaps and is dense with other processes such as hull hoisting, painting, and outfitting, making construction coordination difficult, posing high safety risks, and easily causing project delays. Summary of the Invention

[0003] The purpose of this invention is to provide a method for installing a roll-on / roll-off ship ramp, which can solve the above-mentioned problems existing in the prior art.

[0004] To achieve the above objectives, this application adopts the following technical solution:

[0005] On the one hand, a method for installing a roll-on / roll-off ship ramp is provided, including the following steps: S1. The hull foundation section corresponding to the installation area of ​​the hoisting and roll-on ramp is calibrated in three dimensions with the hull design baseline and rib line as the core reference. After the calibrated hull foundation section is calibrated, all-position welding is performed to form a rigid reference foundation for the ramp installation. S2. Mark the hinge seat installation baseline at the ramp installation position of the hull foundation section, hoist the hull end hinge seat along the installation baseline, perform coaxiality calibration on the hull end hinge seat, and weld and fix the hull end hinge seat after calibration. S3. Lift the ramp body, connect the hinged end of the ramp body to the hinge seat at the hull end through the shaft, drive the ramp body to rotate to the preset horizontal position, perform level calibration on the ramp body, and insert the limit pin to perform temporary locking; Lift the ramp cover, align the ramp cover and place it on the mating end of the ramp body, perform mating accuracy calibration on the ramp cover and ramp body, simultaneously measure the amount of adhesive applied to the mating surfaces of the two, and mark the relative installation reference of the two. S4. The lifting ramp body and the multiple movable decks corresponding to the ramp cover are lifted to the preset temporary work position and the adjustable slow lifting is fixed so that the movable decks avoid the lifting path of the upper section. S5. The upper section above the hoisting ramp installation area is positioned, calibrated and welded to form a complete hull superstructure. S6. Release the temporary locks on the ramp body and ramp cover, hoist them to the temporary placement position, clean the perimeter of the ramp installation position, install the pressure groove and sealing strip, then reset the ramp body and ramp cover according to the marked relative installation reference, and assemble the ramp's matching electrical accessories and outfitting parts in sequence.

[0006] Furthermore, in step S1, during the three-dimensional positioning calibration process, a total station is used to detect the position of the hull foundation section in the X, Y, and Z directions in real time, and the position of the section is adjusted until the position deviation is no more than 1mm; after the welding operation is completed, the flatness of the hinge seat mounting surface of the hull foundation section is detected, and a scraper is used to grind the mounting surface until the flatness error of the mounting surface is no more than 0.5mm / m.

[0007] Furthermore, in step S2, during the coaxiality calibration process, a laser coaxiality detector is used to detect the shaft holes of the hinge seats on both sides of the hull in real time, and the position of the hinge seats is adjusted until the coaxiality error of the shaft holes is no more than 0.3mm; the welding operation is performed in a symmetrical segmented welding manner, and the coaxiality change of the hinge seats is monitored synchronously during the welding process, and the position correction is performed immediately when the deviation exceeds the tolerance.

[0008] Furthermore, in step S3, during the levelness calibration process, a level is used to perform real-time multi-point detection on the upper surface of the ramp body, and the attitude of the ramp body is adjusted with the help of a jack until the levelness error of the ramp body is no greater than 2mm / m; after inserting the limit pin, the pin is locked to prevent it from coming off.

[0009] Furthermore, in step S3, during the calibration of the fit accuracy, a three-dimensional laser scanner is first used to scan the mating surfaces of the ramp body and the ramp cover to obtain a three-dimensional model. After that, virtual pre-matching is performed, and the hoisting posture of the ramp cover is adjusted according to the virtual pre-matching results. After the physical alignment, a feeler gauge is used to measure the mating gap between the two, and the gap is adjusted to a uniform deviation of no more than 0.2mm. At the same time, the amount of adhesive applied to the mating surfaces is measured using the lead pressing method to ensure that the deviation of the amount of adhesive applied is within ±0.2mm of the design value.

[0010] Furthermore, after step S3 is completed, all hot work related to ramp installation, including welding, grinding, and cutting, is immediately performed. After all hot work is completed and passes inspection, the subsequent step S4 is then performed.

[0011] Furthermore, in step S4, during the process of adjusting the slow-lifting fixation, the permanent lifting lugs pre-installed on the hull are used as lifting points, and the movable deck is lifted and fixed in conjunction with the adjustable lifting tool with tension sensor. The tension of the lifting tool is monitored in real time, and the tension of each lifting tool is adjusted to be uniform to ensure that the deformation of the movable deck is not greater than 1mm. The temporary fixing position avoids the lifting operation range of the upper section.

[0012] Furthermore, in step S5, before hoisting the upper section, a secondary inspection is performed on the temporary fixed state of the ramp body, ramp cover and movable deck, and a protective covering operation is performed on the mating surfaces of the ramp; during the hoisting process, the distance between the upper section and the lower structure is monitored in real time to limit structural displacement caused by hoisting collisions.

[0013] Furthermore, in step S6, before installing the sealing strip, the cleanliness of the pressure groove is tested to remove oil, rust and impurities. Then, a sealing primer is applied to the pressure groove before the sealing strip is embedded. After embedding, a pre-compression test is performed on the sealing strip to verify that the sealing performance meets the design requirements before the ramp body and ramp cover are reset.

[0014] Furthermore, the method is applicable to the installation of mobile roll-on / roll-off ramps and side ramps on roll-on / roll-off ships, passenger roll-on / roll-off ships, and car carriers with a rated load capacity of not less than 20t.

[0015] The beneficial effects of this application are as follows: Addressing the aforementioned shortcomings of existing roll-on / roll-off ramp installation methods, this application achieves significant technical benefits through innovative improvements such as process logic reconstruction, closed-loop control of installation accuracy throughout the entire process, and optimization of work sequence. It not only moves the core pre-matching process of the ramp and cover to before the hoisting of the upper section, completely eliminating the rigid waiting time of the original process and significantly reducing the overall construction cycle, thus greatly improving shipbuilding efficiency, but also establishes a closed-loop transfer system for the entire process installation benchmark. Through high-precision testing methods, it achieves full controllability of the matching parameters, fundamentally ensuring the sealing performance and reliability of the ramp, and significantly reducing the later rework rate. All temporary auxiliary structures were eliminated, and permanent hull lifting lugs were used in conjunction with adjustable lifting equipment for construction. This not only avoided structural damage to the hull material but also reduced ineffective work, manpower, and material consumption, thus lowering construction costs. In addition, all hot work was completed before painting, completely avoiding damage to the anti-corrosion layer caused by hot work after painting, ensuring the integrity and long service life of the hull's anti-corrosion layer. It also completely avoided the cross-operation of multiple processes, eliminating safety hazards caused by overlapping operations such as lifting and hot work, and reducing the difficulty of construction coordination and management. At the same time, this method can be directly applied to the installation of movable ramps and side gangplanks on various types of roll-on / roll-off ships and passenger roll-on / roll-off ships, making it widely applicable. Attached Figure Description

[0016] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a schematic flowchart illustrating the installation method of the roll-on / roll-off ship ramp described in the embodiments of this application. Detailed Implementation

[0018] To make the technical problems solved by this application, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this application are further described in detail below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0021] This embodiment provides a method for installing a roll-on / roll-off ship ramp, such as... Figure 1 As shown, it includes the following steps: S1. The hull foundation section corresponding to the installation area of ​​the hoisting and roll-on ramp is calibrated in three dimensions with the hull design baseline and rib line as the core reference. After the calibrated hull foundation section is calibrated, all-position welding is performed to form a rigid reference foundation for the ramp installation. S2. Mark the hinge seat installation baseline at the ramp installation position of the hull foundation section, hoist the hull end hinge seat along the installation baseline, perform coaxiality calibration on the hull end hinge seat, and weld and fix the hull end hinge seat after calibration. S3. Lift the ramp body, connect the hinged end of the ramp body to the hinge seat at the hull end through the shaft, drive the ramp body to rotate to the preset horizontal position, perform level calibration on the ramp body, and insert the limit pin to perform temporary locking; Lift the ramp cover, align the ramp cover and place it on the mating end of the ramp body, perform mating accuracy calibration on the ramp cover and ramp body, simultaneously measure the amount of adhesive applied to the mating surfaces of the two, and mark the relative installation reference of the two. S4. The lifting ramp body and the multiple movable decks corresponding to the ramp cover are lifted to the preset temporary work position and the adjustable slow lifting is fixed so that the movable decks avoid the lifting path of the upper section. S5. The upper section above the hoisting ramp installation area is positioned, calibrated and welded to form a complete hull superstructure. S6. Release the temporary locks on the ramp body and ramp cover, hoist them to the temporary placement position, clean the perimeter of the ramp installation position, install the pressure groove and sealing strip, then reset the ramp body and ramp cover according to the marked relative installation reference, and assemble the ramp's matching electrical accessories and outfitting parts in sequence.

[0022] Based on the above scheme, using the hull design baseline and rib lines as core benchmarks, the three-dimensional positioning calibration and all-position welding of the corresponding hull foundation sections in the ramp installation area are first completed to establish a stable rigid installation benchmark. Then, based on the unified benchmark, the marking, positioning, coaxiality calibration, and welding fixation of the hull end hinge seats are completed, realizing the accurate transfer of the installation benchmark from the hull section to the hinge component, providing a reliable positioning foundation for the subsequent ramp installation. By advancing the core matching processes such as the alignment and assembly of the ramp body and the ramp cover, the fitting accuracy calibration, and the measurement of the adhesive application amount, to before the hoisting of the upper section, the installation is completed. The full parameter calibration and relative position marking of the ramp and cover were completed in an open working space without the obstruction of the hull structure. This completely eliminated the rigid waiting period caused by the existing technology that required the upper section to be fully closed before core operations could be carried out. This significantly reduced the overall construction cycle and improved the efficiency of shipbuilding. It also completely avoided the problems of limited operation and insufficient precision control caused by working in small and enclosed compartments. It achieved precise control of core functional parameters such as fit clearance and pressure application, which fundamentally prevented the occurrence of usage failures such as sealing failure and rotation jamming, and greatly reduced the cost of rework in the later stage.

[0023] Meanwhile, through optimized design with pre-process preparation, the ramps and movable decks are directly hoisted and temporarily secured using pre-installed permanent lifting lugs on the hull and large-scale hoisting equipment for the main sections. This completely eliminates redundant auxiliary structures such as temporary lifting brackets and circular pipe supports required by existing technologies. This reduces a large amount of ineffective work caused by the installation, dismantling, and grinding of temporary structures, lowers the additional consumption of manpower and materials, and avoids mechanical damage to the hull base material and original anti-corrosion coating caused by temporary welding operations, thus eliminating safety hazards and corrosion risks in the long-term use of the hull structure. In addition, this solution concentrates all hot work operations such as welding and grinding involved in the entire ramp installation process before the hoisting of the upper main sections and the overall hull painting operation, completely avoiding hot work operations after painting is completed. The disruption of the hull's anti-corrosion layer ensures its integrity and consistent anti-corrosion performance, effectively extending the service life of the hull structure. Furthermore, through rational planning of the process sequence, the core operation of ramp installation is completely separated from parallel processes such as the hoisting of the upper hull sections, overall painting, and cabin outfitting. This thoroughly avoids the problems of high construction coordination difficulty, frequent operational conflicts, and high safety risks caused by multiple overlapping operations, effectively improving the management efficiency and construction safety of shipbuilding. Moreover, the process logic of this method has strong versatility and replicability, and can be directly applied to the installation of similar articulated functional structures such as ramps and side ramps on various types of roll-on / roll-off ships, passenger roll-on / roll-off ships, and car carriers, demonstrating its high versatility.

[0024] Furthermore, in step S1, during the three-dimensional positioning calibration, a total station is used to detect the positional accuracy of the hull foundation section in the X, Y, and Z directions in real time, and the section position is adjusted until the positional deviation is no greater than 1 mm. After the welding operation is completed, the flatness of the hinge seat mounting surface of the hull foundation section is checked, and a scraper is used to grind the mounting surface until the flatness error of the mounting surface is no greater than 0.5 mm / m. Through the dual closed-loop control of the positioning accuracy and mounting surface accuracy of the hull foundation section, a high-precision rigid reference system is established for the entire process installation of the roll-on / roll-off ramp, which has significant technical benefit effects. As the underlying reference carrier for the installation of the roll-on / roll-off ramp, the accuracy of the three-dimensional spatial position of the hull foundation section directly determines the accuracy of the installation reference transfer for all subsequent components such as hinge seats and the ramp body. This technical feature employs a total station to perform real-time positional detection of the hull foundation section in the X, Y, and Z directions. Leveraging the millimeter-level high-precision three-dimensional measurement capabilities of the total station, dynamic calibration is achieved during the hoisting and positioning process of the section, strictly controlling the positional deviation of the section to within 1mm. This establishes a unified reference consistent with the hull design coordinate system from the very beginning of installation, completely avoiding the cumulative errors in subsequent installation procedures caused by positioning deviations of the foundation section. Simultaneously, addressing the unavoidable welding deformation problem during the welding operation of the foundation section, after welding... After completion, the flatness of the hinge seat mounting surface is inspected, and the flatness error is controlled within 0.5mm / m through precision grinding with a scraper. This effectively eliminates defects such as warping and unevenness of the mounting surface caused by welding deformation, ensuring uniform contact between the subsequent hull-end hinge seat and the mounting surface. It avoids problems such as uneven load and misalignment of shaft holes after the hinge seat is installed due to uneven mounting surface. This provides a reliable benchmark for the subsequent coaxiality calibration of the hinge seat and the attitude adjustment of the ramp body. It reduces the workload of repeated calibration and adjustment in subsequent processes from the root, improving the overall installation accuracy and efficiency of the ramp, and ensuring the long-term operational stability, smooth rotation, and load-bearing safety of the ramp hinge structure.

[0025] Furthermore, in step S2, during the coaxiality calibration process, a laser coaxiality detector is used to detect the shaft holes of the hinge seats on both sides of the hull in real time, and the position of the hinge seats is adjusted until the coaxiality error of the shaft holes is no more than 0.3mm; the welding operation is performed in a symmetrical segmented welding manner, and the coaxiality change of the hinge seats is monitored synchronously during the welding process, and the position correction is performed immediately when the deviation exceeds the tolerance. As the core load-bearing hinge component connecting the ramp body and the hull structure, the coaxiality accuracy of the shaft holes on both sides of the hull end hinge seat directly determines the smoothness of ramp rotation, the uniformity of stress on the hinge structure, and its long-term service life. A laser coaxiality measuring instrument is used to perform real-time detection of the shaft holes on both sides of the hull end hinge seat. Leveraging the advantages of non-contact, high-resolution, and real-time feedback technology of laser detection, the spatial positional deviation of the shaft holes on both sides is accurately captured, strictly controlling the coaxiality error of the shaft holes to within 0.3mm. This achieves high-precision alignment of the hinge reference during the pre-installation stage, fundamentally avoiding problems such as difficulty in hinge shaft insertion, ramp rotation jamming, and uneven wear at the hinge joint caused by excessive coaxiality deviation. Simultaneously, a symmetrical segmented welding process is used for welding fixation, utilizing symmetrically distributed heat input to offset the heat generated during the welding process. The uneven welding stress generated reduces welding deformation at the source of the process. Furthermore, the coaxiality of the hinge seat is monitored synchronously throughout the welding process, allowing for immediate position correction as soon as welding deformation begins to show signs of exceeding tolerances. This completely avoids the drawbacks of traditional welding processes that require "welding first, then measuring, and reworking after deformation exceeds tolerances." This ensures the stability of the coaxiality accuracy of the hinge seat after welding, significantly improving the first-pass yield rate of hinge seat installation and reducing the amount of ineffective rework and adjustment later. It also achieves precise transfer from the hull foundation section benchmark to the hinge component benchmark, providing a stable and reliable hinge benchmark for subsequent ramp body attitude calibration and ramp-to-cover matching. This avoids cumulative errors during installation, further ensuring the consistency of the entire ramp installation system's precision and improving the load-bearing safety and long-term operational reliability of the roll-on / roll-off ramp.

[0026] In some embodiments, during step S3, a level instrument is used to perform real-time multi-point detection on the upper surface of the ramp body, and a jack is used to adjust the attitude of the ramp body until the levelness error of the ramp body is no greater than 2mm / m; after inserting the limit pin, an anti-disengagement locking operation is performed on the pin. As a core functional component that achieves a sealed fit and synchronized operation with the ramp cover, the consistency of the ramp body's horizontal posture directly determines the uniformity of the gap between the two mating surfaces and the control precision of the adhesive application. It also directly affects the uniformity of stress and the smoothness of rotation of the hinged structure. This technology employs a level to perform real-time multi-point detection on the upper surface of the ramp body. The layout of multiple measuring points comprehensively covers the entire load-bearing plane of the ramp body, accurately capturing overall tilt, local warping, and other full-dimensional posture deviations, completely avoiding the detection blind spots and data distortion problems caused by single-point detection. Simultaneously, a jack is used to dynamically fine-tune the ramp body's posture in multiple dimensions, strictly controlling the horizontality error of the ramp body within 2mm / m. This achieves high-precision closed-loop calibration of the ramp body's posture, ensuring that the flatness of the ramp mating surfaces is completely consistent with the hull design benchmark. This fundamentally avoids problems such as uneven mating gaps and excessive adhesive application deviations caused by ramp tilt, effectively guaranteeing the sealing performance of the ramp and cover fit, and significantly reducing the risk and cost of later repairs due to insufficient fit precision. Furthermore, performing an anti-loosening locking operation on the limit pin after insertion effectively avoids pin loosening and ramp body posture displacement caused by vibration and accidental collisions during subsequent hoisting operations and upper section construction. This ensures the stability and consistency of the calibrated ramp posture throughout the entire construction process, completely avoiding the ineffective work of repeated calibration and adjustment required due to changes in ramp posture in subsequent processes, and further improving the overall installation efficiency and the reliability of installation accuracy. At the same time, precise level calibration also ensures the uniformity of force on the ramp hinge shaft during the full stroke rotation process, avoiding faults such as uneven load wear and rotation jamming of the hinge shaft caused by ramp posture deviation, effectively improving the long-term operational stability and service life of the roll-on / roll-off ramp hinge structure.

[0027] Meanwhile, in step S3, during the calibration of the fit accuracy, a three-dimensional laser scanner is first used to scan the mating surfaces of the ramp body and the ramp cover to obtain a three-dimensional model. After that, virtual pre-matching is performed, and the hoisting posture of the ramp cover is adjusted according to the virtual pre-matching results. After the physical alignment, a feeler gauge is used to measure the mating gap between the two, and the gap is adjusted to a uniform deviation of no more than 0.2mm. At the same time, the amount of adhesive applied to the mating surfaces is measured using the lead pressing method to ensure that the deviation of the amount of adhesive applied is within ±0.2mm of the design value. Addressing the challenges of large dimensions, complex mating surfaces, and difficult physical alignment adjustments in roll-on / roll-off ramps and ramp covers, this technology employs a 3D laser scanner to perform a full-range non-contact scan of the mating surfaces of the ramp body and ramp cover. This accurately acquires full-size 3D topographic data of the mating surfaces, constructing a digital twin model that perfectly matches the physical structure. Multi-pose pre-matching simulations are then performed in a virtual environment, identifying inherent matching defects such as local protrusions and surface deviations in advance. This allows for the identification of the optimal hoisting alignment posture, completely overturning the inefficient traditional "physical hoisting - manual alignment - repeated adjustments" work mode. This avoids structural damage and wasted lifting resources caused by repeated physical hoisting, significantly reduces the amount of ineffective on-site alignment adjustments, and eliminates potential mating deviations from a digital perspective, providing advance digital guidance for precise physical alignment. This avoids the blindness of physical adjustments. After completing the physical alignment guided by virtual pre-matching, a feeler gauge is used to continuously measure the gap between the ramp body and the ramp cover at multiple points. The uniform deviation of the gap is strictly controlled within 0.2mm, ensuring the smoothness and consistency of the gap between the two mating surfaces. This fundamentally avoids problems such as ramp rotation interference and misalignment caused by excessive or insufficient local gaps. At the same time, the lead pressing method is used to perform high-precision contact measurement of the amount of adhesive applied to the mating surfaces. The deviation of the amount of adhesive applied is strictly controlled within ±0.2mm of the design value. This precisely ensures that the compression of the sealing strip is uniform across the entire mating surface. It prevents the ramp's waterproof sealing performance from failing due to insufficient compression, and also prevents the sealing strip from being over-compressed and prematurely aging due to excessive compression. This achieves dual precision control of mating accuracy and sealing performance. This technology combines digital pre-simulation with precise physical calibration to achieve one-time molding of the ramp and cover installation, significantly improving the first-pass yield rate of the mating structure installation. It fundamentally avoids the problem of repeated disassembly and rework caused by insufficient mating precision in the later stages. This not only improves the installation efficiency of roll-on / roll-off ramps but also ensures the long-term stable operation of the ramp's core sealing and rotation functions. At the same time, this technical solution can be directly applied to the high-precision installation of various large articulated mating structures and large-size sealing mating surfaces in ships, demonstrating strong engineering practicality.

[0028] In addition, after step S3 is completed, all hot work related to ramp installation, including welding, grinding and cutting, shall be performed immediately. After all hot work is completed and passes inspection, the subsequent step S4 shall be performed.

[0029] Addressing the industry pain points of existing roll-on / roll-off ramp installation processes, such as fragmented hot work sequences, damage to the ship's anti-corrosion layer from hot work after painting, and high safety risks associated with hot work in enclosed compartments, this solution addresses the core deficiencies of existing technologies by rigidly controlling and centrally planning the timing windows for hot work throughout the entire process. This fundamentally resolves these shortcomings in the process design, demonstrating significant engineering value and technological benefits. Its core working principle involves precisely locking the execution window for hot work throughout the ramp installation process. After completing the pre-installation and precision calibration of the ramp body, hull-end hinge seat, and ramp cover in step S3, thus establishing a complete ramp installation benchmark, the ramp... All hot work related to installation, such as welding, grinding, and cutting, is performed centrally and in one go. Only after all hot work is completed and passes quality and safety inspections can the subsequent steps of S4 (movable deck hoisting), S5 (superstructure hoisting), and overall hull painting be initiated. This completely breaks away from the unreasonable process logic of existing technologies that disperse hot work after superstructure assembly and painting, resulting in multi-dimensional technical benefits: Firstly, it fundamentally avoids damage to the hull's anti-corrosion coating caused by hot work after painting, ensuring the integrity and anti-corrosion performance of the hull's anti-corrosion layer. Consistency is achieved, completely avoiding the problems of decreased anti-corrosion performance and shortened structural service life caused by coating repair, and eliminating the safety hazards of long-term rust on the hull structure; secondly, all hot work is carried out in an open and unobstructed space before the upper section is hoisted, completely avoiding the safety problems of poor ventilation, difficult fire rescue, and high risk of flammability and explosion caused by hot work in closed compartments, and greatly improving the construction safety and compliance of hot work; thirdly, centralized hot work can realize the intensive configuration of construction personnel, welding equipment, and fire protection facilities, avoiding the repeated entry and exit of personnel and equipment caused by decentralized operations. The ineffective consumption of leaving the site reduces conflicts with other processes such as hull hoisting, painting, and outfitting, significantly reducing the difficulty of construction coordination and improving overall construction efficiency. Fourth, completing all hot work in a concentrated manner after the ramp installation benchmark calibration can avoid the displacement damage caused by welding stress and construction vibration from subsequent dispersed hot work to the calibrated ramp installation accuracy and matching benchmark, ensuring the long-term stability of the installation accuracy calibrated in the early stage, reducing the amount of rework work required for repeated adjustments due to accuracy deviations in the later stage, and further improving the first-pass yield and construction quality stability of ramp installation.

[0030] Optionally, in step S4, during the process of adjusting the slow hoisting and fixing, the permanent lifting lugs pre-installed on the hull are used as the hoisting points, and the movable deck is hoisted and fixed in conjunction with the adjustable lifting tool with tension sensor. The tension of the lifting tool is monitored in real time, and the tension of each lifting tool is adjusted to be uniform to ensure that the deformation of the movable deck is not greater than 1mm. The temporary fixing position avoids the hoisting operation range of the upper section.

[0031] This solution abandons the traditional method of temporary welding of lifting brackets and directly uses the pre-installed permanent lifting lugs on the hull as the lifting and fixing points for the movable deck. Relying on the design load-bearing strength and structural reliability of the permanent lifting lugs, it replaces the temporary auxiliary lifting points without the need for additional temporary structures. At the same time, it uses adjustable lifting equipment with tension sensors to carry out lifting and fixing. The sensors monitor the tension of each lifting point in real time and adjust the tension value of each lifting equipment to a uniform distribution based on the monitoring data. This counteracts the uneven stress caused by the movable deck's own weight and external stress, strictly controlling the deformation of the movable deck to within 1mm, ensuring the flatness and structural accuracy of the deck itself. In addition, when planning the temporary fixing position, it precisely avoids the lifting operation range of the upper section, completely avoiding the interference and collision risks of the two lifting processes from a spatial path perspective. This technology brings significant technical benefits. First, it completely eliminates the welding, dismantling, and grinding operations of temporary lifting brackets, avoiding mechanical damage to the hull material caused by temporary welding and preventing damage to the original anti-corrosion coating. This ensures the integrity of the hull structure and the consistency of its anti-corrosion performance, fundamentally eliminating the safety hazards of long-term rust and strength degradation of the hull structure. Second, by controlling the uniform force at each lifting point, the deformation of the movable deck is precisely limited to within 1mm, effectively ensuring the flatness and structural accuracy of the movable deck and avoiding gaps in subsequent fitment with the ramp and upper section due to deck deformation. Issues such as exceeding standards and misalignment during assembly were addressed, ensuring consistent installation accuracy in subsequent processes and significantly reducing the amount of ineffective rework and adjustments. Thirdly, relying on the combination of permanent lifting lugs and adjustable force control lifting equipment, efficient hoisting and fixing of the movable deck was achieved, eliminating the entire process of temporary structure preparation and improving the construction efficiency of temporary fixing. At the same time, the spatial planning of avoiding the hoisting path of the upper section completely avoided the safety risks of hoisting collisions, significantly reduced conflicts between cross-operations, improved construction coordination efficiency and on-site operation safety, and achieved a seamless and orderly connection between the temporary fixing of the movable deck and the hoisting process of the upper section.

[0032] Generally, in step S5, before hoisting the upper section, a secondary inspection is performed on the temporary fixed state of the ramp body, ramp cover and movable deck, and protective covering is performed on the mating surfaces of the ramp; during the hoisting process, the distance between the upper section and the lower structure is monitored in real time to limit structural displacement caused by hoisting collisions. Before the hoisting of the upper section, a second comprehensive verification was conducted on the ramp body, ramp cover, and the temporary fixation status of the movable deck, which had been precisely calibrated and temporarily locked. The reliability and stability of the connection of the limiters, lifting tools, and locking structures were confirmed one by one, and potential hazards such as loosening and displacement were identified in advance. At the same time, protective covering was applied to the precision mating surfaces of the ramp and ramp cover to form a physical protective barrier to isolate external interference such as dust, welding slag, and collisions and scratches during the hoisting process. During the actual hoisting of the upper section, the distance between the section and the lower hull structure, ramp, and movable deck was monitored in real time. The hoisting posture and travel speed of the section were adjusted in a timely manner based on the monitoring data to avoid problems such as hard collisions and scrapes during dynamic construction, and to completely eliminate structural displacement, damage to the base material, or damage to the precision benchmark caused by the hoisting operation.

[0033] Optionally, in step S6, before installing the sealing strip, the cleanliness of the pressure groove is tested to remove oil, rust and impurities. Then, a sealing primer is applied to the pressure groove before the sealing strip is embedded. After embedding, a pre-compression test is performed on the sealing strip to verify that the sealing performance meets the design requirements before the ramp body and ramp cover are reset. Before installing the sealing strip, a special cleanliness test is performed on the pressure groove to accurately identify and remove contaminants such as oil, rust, and impurities. Then, professional cleaning methods are used to thoroughly remove all contaminants, ensuring the cleanliness and flatness of the pressure groove's bonding surface. Next, a sealing primer is applied to the pressure groove to optimize the compatibility of the adhesive interface between the strip and the metal groove, improving their bonding strength and tightness. After the sealing strip is embedded in the pressure groove, a pre-compression test is immediately performed to simulate the actual compression conditions after the ramp body and ramp cover are reset. This verifies in advance whether the uniformity of the strip's compression and the overall sealing performance meet design requirements. Only after the sealing performance verification is passed can the ramp body and ramp cover be reset, achieving pre-emptive closed-loop control of sealing performance.

[0034] In one solution, the method is applicable to the installation of movable ro-ro ramps and side ramps on ro-ro ships, passenger ro-ro ships, and car carriers with a rated load capacity of not less than 20t. The core technical solutions designed in this solution, such as process reconfiguration, closed-loop precision control throughout the entire process, hoisting and fixing without temporary structures, and hot work sequence planning, are not designed for a single ship type or a single light-load ramp structure. The high-precision installation indicators set for three-dimensional positioning, coaxiality, and levelness, as well as the hoisting and fixing methods relying on permanent lifting lugs and force-controlled spreaders, are all adapted to the installation mechanics requirements and precision standards of heavy-duty articulated loading and unloading structures with a rated load capacity of not less than 20t. Simultaneously, it is compatible with the hull structure design characteristics of ro-ro ships, passenger ro-ro ships, and car carriers, as well as the common installation technologies of similar articulated sealed loading and unloading components such as movable ro-ro ramps and side ramps. This breaks through the application limitations of a single ship type and a single equipment, realizing the cross-category and cross-ship type reuse of the technical solution in the field of heavy-duty articulated loading and unloading equipment installation.

[0035] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and other orientations or positional relationships are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used merely for descriptive distinction and have no special meaning.

[0036] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0038] The technical principles of this application have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this application without inventive effort, and these embodiments will all fall within the scope of protection of this application.

Claims

1. A method for installing a ramp for roll-on / roll-off ships, characterized in that, Includes the following steps: S1. The hull foundation section corresponding to the installation area of ​​the hoisting and roll-on ramp is calibrated in three dimensions with the hull design baseline and rib line as the core reference. After the calibrated hull foundation section is calibrated, all-position welding is performed to form a rigid reference foundation for the ramp installation. S2. Mark the hinge seat installation baseline at the ramp installation position of the hull foundation section, hoist the hull end hinge seat along the installation baseline, perform coaxiality calibration on the hull end hinge seat, and weld and fix the hull end hinge seat after calibration. S3. Lift the ramp body, connect the hinged end of the ramp body to the hinge seat at the hull end through the shaft, drive the ramp body to rotate to the preset horizontal position, perform level calibration on the ramp body, and insert the limit pin to perform temporary locking; Lift the ramp cover, align the ramp cover and place it on the mating end of the ramp body, perform mating accuracy calibration on the ramp cover and ramp body, simultaneously measure the amount of adhesive applied to the mating surfaces of the two, and mark the relative installation reference of the two. S4. The lifting ramp body and the multiple movable decks corresponding to the ramp cover are lifted to the preset temporary work position and the adjustable slow lifting is fixed so that the movable decks avoid the lifting path of the upper section. S5. The upper section above the hoisting ramp installation area is positioned, calibrated and welded to form a complete hull superstructure. S6. Release the temporary locks on the ramp body and ramp cover, hoist them to the temporary placement position, clean the perimeter of the ramp installation position, install the pressure groove and sealing strip, then reset the ramp body and ramp cover according to the marked relative installation reference, and assemble the ramp's matching electrical accessories and outfitting parts in sequence.

2. The installation method of the roll-on / roll-off ship ramp according to claim 1, characterized in that, In step S1, during the three-dimensional positioning calibration, a total station is used to detect the position of the hull foundation section in the X, Y, and Z directions in real time, and the position of the section is adjusted until the position deviation is no more than 1 mm. After the welding operation is completed, the flatness of the hinge seat mounting surface of the hull foundation section is detected, and a scraper is used to grind the mounting surface until the flatness error of the mounting surface is no more than 0.5 mm / m.

3. The installation method of the roll-on / roll-off ship ramp according to claim 1, characterized in that, In step S2, during the coaxiality calibration process, a laser coaxiality detector is used to detect the shaft holes of the hinge seats on both sides of the hull in real time, and the position of the hinge seats is adjusted until the coaxiality error of the shaft holes is no more than 0.3mm. The welding operation is carried out in a symmetrical segmented welding manner, and the coaxiality change of the hinge seats is monitored synchronously during the welding process. If the deviation exceeds the tolerance, the position correction is immediately performed.

4. The installation method of the roll-on / roll-off ship ramp according to claim 1, characterized in that, In step S3, during the levelness calibration process, a level is used to perform real-time multi-point detection on the upper surface of the ramp body, and the attitude of the ramp body is adjusted with the help of a jack until the levelness error of the ramp body is no more than 2mm / m; after inserting the limit pin, the pin is locked to prevent it from coming off.

5. The installation method of the roll-on / roll-off ship ramp according to claim 1, characterized in that, In step S3, during the calibration of the fit accuracy, a 3D laser scanner is first used to scan the mating surfaces of the ramp body and the ramp cover to obtain a 3D model. After that, virtual pre-matching is performed, and the hoisting posture of the ramp cover is adjusted according to the virtual pre-matching results. After the physical alignment, a feeler gauge is used to measure the mating gap between the two and the gap is adjusted to a uniform deviation of no more than 0.2mm. At the same time, the amount of adhesive applied to the mating surfaces is measured using the lead pressing method to ensure that the deviation of the amount of adhesive applied is within ±0.2mm of the design value.

6. The method for installing a roll-on / roll-off ship ramp according to any one of claims 1-5, characterized in that, After step S3 is completed, immediately perform all hot work related to ramp installation, including welding, grinding, and cutting. After all hot work is completed and passes inspection, proceed with the subsequent step S4.

7. The method for installing a roll-on / roll-off ship ramp according to any one of claims 1-5, characterized in that, In step S4, during the process of adjusting the slow hoisting and fixing, the permanent lifting lugs pre-installed on the hull are used as the hoisting points. Adjustable lifting tools with tension sensors are used to hoist and fix the movable deck. The tension of the lifting tools is monitored in real time, and the tension of each lifting tool is adjusted to be uniform to ensure that the deformation of the movable deck is not greater than 1mm. The temporary fixing position avoids the hoisting operation range of the upper section.

8. The method for installing a roll-on / roll-off ship ramp according to any one of claims 1-5, characterized in that, In step S5, before hoisting the upper section, a secondary inspection is performed on the temporary fixed state of the ramp body, ramp cover and movable deck, and protective covering is performed on the mating surfaces of the ramp; during the hoisting process, the distance between the upper section and the lower structure is monitored in real time to limit structural displacement caused by hoisting collisions.

9. The method for installing a roll-on / roll-off ship ramp according to any one of claims 1-5, characterized in that, In step S6, before installing the sealing strip, the cleanliness of the pressure groove is tested to remove oil, rust and impurities. Then, a sealing primer is applied to the pressure groove before the sealing strip is embedded. After embedding, a pre-compression test is performed on the sealing strip to verify that the sealing performance meets the design requirements. Then, the ramp body and ramp cover are reset.

10. The method for installing a roll-on / roll-off ship ramp according to any one of claims 1-5, characterized in that, The method is applicable to the installation of mobile roll-on / roll-off ramps and side ramps on roll-on / roll-off ships, passenger roll-on / roll-off ships, and car carriers with a rated load capacity of not less than 20t.

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