Thursday, February 26, 2026

 Bài 8, cũng là bài cuối của loạt bài về kết cấu của Bảo tàng Edo Tokyo

This image displays a page from a 1994 technical journal titled "Steel Construction Engineering" concerning welding techniques for structural steel.
• It details the use of two-electrode automatic electroslag welding for 80mm thick TMCP (Thermo-Mechanically Controlled Processing) steel.
• The article includes technical tables regarding welding conditions and mechanical test results such as tensile, impact, and hardness tests.
• The document concludes by emphasizing that the construction method met all mechanical properties and building standards without issue.
Translation
• Steel Construction Engineering Vol. 1 No. 1 (March. 1994)
• After removing the end tabs, the flange groove was shaped with a grinder, and after adjusting the groove, a penetrant inspection confirmed that there were no gouging residues or defects inside the groove, and the work was completed.
• Table 3 Welding Conditions
• Voltage (V)
• Figure 13 Welding part Vickers hardness test results
• Table 4 Test Results
• Photo 9 Automatic electroslag welding
• 6.4 Mechanical Testing
• Although TMCP steel has a lower carbon equivalent and better weldability compared to conventional SM430A, etc., this project uses two-electrode automatic electroslag welding, which is a high heat input welding method, on 80mm thick material. Therefore, strength, impact characteristics, and hardness tests were performed on the welded joint area to confirm that the mechanical properties satisfied those at the time of TMCP material minister certification acquisition.
• The test specimen was BH-500X500X50X50 (TMCP F-3.3t/㎡), and an electroslag welding test was performed under the same conditions as on-site construction.
• The test items are ultrasonic flaw detection test, tensile test, impact test (test temperature 0 degrees), bending test, macro test, and hardness test. The test results are shown in Figure 13 and Table 4. All test results satisfied the base material standard values, and it was confirmed that the bending test results showed no cracks and had good bending ductility. In addition, no defects were observed in the macro test, and it was confirmed that the fusion into the base material was sufficient. In the hardness test results, the maximum hardness was HV203 and the minimum hardness was HV141, and no particular abnormalities were observed.
• 7 Conclusion
• Due to the peculiarity of its shape, this building became a large-scale steel structure, and the weight of a single piece became large. Therefore, the design proceeded while paying attention to the workability and construction method of on-site welding from the design stage. Also, regarding construction, the construction method was examined during the planning stage, and the most rational construction method was adopted. As a result, the construction proceeded without any particular problems.
• In conclusion, I would like to express my sincere gratitude to everyone involved who guided us from the planning of this construction to the completion.
• References
• (1) Kojima Kenji, Miyamura Masamitsu, Kanda Tomohiro, Tsuji Shinichi, Suzuki Kazuo et al., Development of Large-scale Vertical Movement System (Part 1), Architectural Institute of Japan Academic Lecture (November 7, 1983)
• -94-
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 Bài 7 của loạt bài về kết cấu của Bảo tàng Edo Tokyo

This document is a page from a Japanese technical journal, Journal of Structural Construction Engineering (Volume 1, Issue 1, 1994), detailing a specific welding system for steel construction.
• Welding Method: The text describes using a consumable nozzle electro-slag welding process for site construction to simplify equipment needs.
• System Components: The system utilizes a steel-backed backing plate on one side and a water-cooled steel backing plate on the other, eliminating the need to raise or lower the welding machine body.
• Welding Equipment: The welding power supply requires a capacity of roughly 600A to 1000A, and the setup includes a welding machine, wire reel, and vertical/horizontal adjustment devices.
• Procedure Details: The document outlines procedures for managing root gaps (set to 25mm), preventing misalignment to avoid slag leaks, and performing preheating to approximately 50°C to remove moisture.
Translation
• Header: Journal of Structural Construction Engineering, Volume 1, Issue 1 (March 1994)
• Section 6.2 Welding System: For on-site construction, this project used consumable nozzle electroslag welding to simplify the equipment as much as possible, with one side of the backing material made of steel and the other side a water-cooled steel backing plate. This method melts the steel electrode nozzle simultaneously with the wire, eliminating the need to raise or lower the welding machine body, allowing the steel backing plate to be tightly fixed from the beginning, and simplifying the equipment and operation. Table 2 shows the welding equipment and materials. As the welding power source usage is high, a capacity of about 600A to 1000A is required. The wire feeding control method uses a voltage control system, and for operational purposes, it consists of a control box and an operation box equipped with switches, current, and voltage meters necessary for direct operation.
• Figure 11: Example of field joints for large columns and beams
• Figure 12: Groove shape and backing plate installation status
• Section 6.3 Working Procedure: The main work procedures are shown below. Due to assembly errors, the established root gap may become narrower than set. In such cases, an arc may occur between the base metal or the backing plate, causing welding defects, or the molten metal in the slag pool may not convect sufficiently, causing lack of fusion. Therefore, the groove spacing was made as close to the designated spacing as possible. In particular, it is difficult to adjust the groove spacing after the erection is completed, so construction was carried out while checking the groove condition during erection. Also, if the groove misalignment is large, it causes slag leakage and undercutting, so the misalignment was kept to 1mm or less. If moisture enters during welding, it boils in the slag pool, blowing up the molten slag and deteriorating the welding appearance and fusion. Therefore, moisture on the groove surface was thoroughly removed before starting welding. Also, preheating is not necessary for electroslag welding, which has a large heat input, but preheating to about 50°C was performed for the purpose of cleaning and moisture removal. The quality of the installation of the start tab, end tab, and copper backing plate causes molten metal leakage and welding defects, so careful installation was performed. The copper backing plate was securely installed using fixing jigs and wedges.
• Table 3: Welding conditions are shown in Table 3. For the welding start part, preheating tends to improve fusion for thick plates, so the start part was preheated to about 60°C. The welding time was about 2 to 3 hours, during which the copper backing plates were replaced in sequence. After welding was completed, the start tab was removed. Since the end tab is provided at the upper flange groove part, it interferes with the welding of the upper flange along with the slag in the groove part. Therefore, the slag inside the upper flange groove was removed with an arc air gouge.
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 Bài 6 của loạt bài về kết cấu của Bảo tàng Edo Tokyo

The image displays a technical document titled "Steel Construction Engineering" from March 1994, specifically detailing the erection steps and welding processes for large steel structures.
• The document outlines a five-step erection process (STEP 1-5) for steel beam construction. [1]
• It describes a method for site automatic electroslag welding on beam webs to reduce construction time. [2]
• The procedure applies to specific conditions, such as plates thicker than 40mm, constant thickness, and required overhead working space. [3]
Translation
| Section | English Translation |
| --- | --- |
| Title | Steel Construction Engineering Vol. |
| Step Titles | Construction STEP 1, STEP 2, STEP 3, STEP 4, STEP 5 |
| Subtitle | 6 Site Electroslag Welding |
| Subsection | 6.1 Overview of Site Automatic Electroslag Welding |
| Technical Details | To reduce the construction period for site welding, the automatic electroslag welding method was used for beam webs if the plate thickness was 40 mm or more with no change in thickness and a working space of 1 m or more could be secured above. |
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 Bài 5 của loạt bài về kết cấu của Bảo tàng Edo Tokyo

This document is a technical paper detailing the construction planning for a large-scale steel structural frame, specifically highlighting the assembly of "super columns" and "super beams" for a high-rise building. [1, 2]
• Structural Details: The steel structure has a total weight of 23,000 tons, with a maximum plate thickness of 100mm and a maximum piece weight of approximately 40 tons.
• Construction Method: A 400t crawler crane is used to lift four super columns first, followed by the installation of jib cranes on top to assemble the super beams on temporary bents.
• Welding and Joining: Due to the large cross-sections, major structural joints are bolted, and thick plates (over 40mm) use automatic electroslag welding for vertical joints, while others use CO2 semi-automatic welding.
Translation
• Figure-2 Installation of vibration control device
• Figure-3 Vibration control device main body
• 5 Construction
• 1) Steel Frame Structure: Both large columns and large beams are truss shapes combined with large-section single members. It is expected that unignorable construction stress will occur if the deformation caused during construction is corrected. Therefore, the construction plan aimed to minimize the need for correction and minimize construction stress.
• 2) Large Section Framework: Due to transportation weight limits per piece, the number of joints increases, with 7,900 major members, 700,000 high-strength bolts, and 250,000m of field welding (6mm conversion). Considering member shrinkage from field welding, main beam joints are bolted to prevent welding cracks and stress.
• 3) Thick Plates: Many steel members are thick (max 100mm) with large welding volumes. For field welding, beam webs thicker than 40mm use automatic electroslag welding suitable for vertical welding. Otherwise, CO2 semi-automatic welding is used. Upper and lower flanges use CO2 semi-automatic welding.
• STEP 1 Crawler crane
• STEP 2 3500tm jib crane
• Journal of Structural Construction Engineering Vol. 1 No. 1 (March 1994)
• 5.1 Steel Frame Erection
• Table-1 Erection Method Plan
• Figure-10 Steel frame erection overview
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 Bài 4 của loạt bài về kết cấu của Bảo tàng Edo Tokyo

This document from "Steel Construction Engineering" (March 1994) details the structural engineering design of a vibration control system for a large-span building.
• The system uses air springs to reduce vibration acceleration from the structural floor by approximately 75%. [1, 2]
• It incorporates hydraulic dampers to absorb earthquake energy and linear slides to manage horizontal forces. [1, 2]
• A total of 252 units were installed to protect exhibition items from vertical earthquake movements. [1, 3]
Translation
• Figure 7: Analytical Model Diagram. Shows the model for static and vibration analysis, assuming the first-floor slab is fixed and mass is concentrated at the intersections of main streets on each floor.
• 4. Vibration Control Device: The design aim is to protect exhibits from earthquakes in large-span structures. A vertical vibration control layer was incorporated into a double floor at the tip of a 2800 $m^2$ cantilever section.
• Design Policies:
1. The primary natural frequency of the device is set to 1Hz or less, as the building's primary frequency is approximately 2Hz.
2. Include a level adjustment function for human walking and exhibit movement.
3. Transfer horizontal shear force to the floor directly below.
4. The maximum vertical stroke of the device is 18 cm or more.
• Figure 8: Layout of vibration control devices.
• Figure 9: Vibration control device.
• Device Components:
• Air Springs: Transfer floor loads to the structural floor below and reduce transmitted vibration acceleration to about 1/4 (primary natural frequency of about 0.8 Hz).
• Hydraulic Dampers: Absorb earthquake energy and suppress amplification near the resonance frequency of the control device.
• Shear Receiving Materials: Transfer horizontal forces during an earthquake to the structural floor.
• Linear Slides: Installed via hard rubber to allow the air spring to move smoothly vertically even when horizontal force is applied to the control device.
• Automatic Level Adjustment Device: Automatically supplies and exhausts air in the air springs to keep the floor level constant despite load changes from rearranging exhibits or large movements of visitors. It does not perform air supply/exhaust during rapid floor load fluctuations like earthquakes, ensuring the response reduction effect of the air spring is not compromised.
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 Bài 3 của loạt bài về kết cấu của Bảo tàng Edo Tokyo.

The image displays a technical document, likely a research paper or engineering report in Japanese, focusing on structural engineering diagrams. [1]
• The document includes foundation plans ("基礎伏図") and structural framing elevations ("通り軸組図") for a steel-framed structure. [1]
• It describes seismic design principles, mentioning the use of braces ("ブレース"), trusses ("トラス"), and specific steel materials ("SM490A") to ensure structural integrity. [1, 2]
• The diagrams outline components like columns and beams, showing their arrangements on different structural grid lines. [1, 2]
Translation
• Figure 2: Foundation Plan
• Figure 3: 6th Floor Framing Plan
• Figure 4: 7th Floor Framing Plan
• Figure 5: A-Grid Framing Elevation
• Figure 6: C-Grid Framing Elevation
• Steel material type: 40mm or less SM490A, Over 40mm is TMCP steel.
• The trusses are designed so that axial forces are dominant in each member.
• Horizontal bracing was installed.
• The foundational design ensures stability against earthquakes.
• Column/beam materials: Box section BH-800x800x80x80.
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Comparison of Reinforced Masonry Shear Wall and Seismic Design Provisions
masonrysociety.org
Comparison of Reinforced Masonry Shear Wall and Seismic Design Provisions
Authors: Ece Erdogmus, Carlos Cruz-Noguez, Phillipe Ledent, Lane Jobe, Kevin Hughes, Bennett Banting, Jason Thompson TMS Journal Volume 42, December 31, 2024 Abstract As part of a larger project titled, CANUS: Harmonization of Canadian and American Masonry Structures Design Standards Project, in thi...

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