Faculty Profiles - SHIMIZU Masaru

FATIGUE STRENGTH IMPROVEMENT OF ROOT-DECK CRACK IN ORTHOTROPIC STEEL DECK BY MODIFYING U-RIB SHAPE

MAEDA Satoshi, TATEISHI Kazuo, HANJI Takeshi, SHIMIZU Masaru, TAKATA Koyo

Japanese Journal of JSCE Vol. 82 ( 2 ) page： n/a 2026

Language：Japanese Publisher：Japan Society of Civil Engineers

This paper investigates the fatigue strength improvement of root-deck crack in orthotropic steel decks with closed ribs by modifying the shape of the U-rib. First, the influence of U-rib width and spacing on stress at the crack initiation point was examined using finite element analysis, and structures expected to have improved fatigue strength compared to a conventional structure were proposed. Next, cyclic loading tests on cross-beam intersection and wheel running tests were conducted on the proposed structure to validate its fatigue strength. Finally, an analytical study on an actual bridge model was performed to quantitatively estimate the fatigue life under service conditions. The results of these studies demonstrate that modifying the U-rib shape is effective in improving the fatigue strength of deck propagation cracks.

DOI： 10.2208/jscejj.25-00223

Bending fatigue strength of slotted tubular joints in transmission steel tower members

SODA Naohiro, TATEISHI Kazuo, HANJI Takeshi, SHIMIZU Masaru

Kou kouzou rombunshuu Vol. 32 ( 128 ) page： 163 - 178 2025.12

Language：Japanese Publisher：Japanese Society of Steel Construction

Slotted tubular joints are commonly used in transmission steel tower members. In these joints, fatigue cracks have been initiated at plate-end welds, tube-end welds and bolted connections due to bending loads. In this study, bending fatigue tests on slotted tubular joints were conducted to investigate fatigue strength based on nominal stress. As a result, cracks at tube-end welds were caused by in-plane bending of the slotted plate, and their fatigue strength satisfied Class H in the Specifications for Highway Bridges. On the other hand, cracks at plate-end welds were caused by out-of-plane bending, and their fatigue strength was higher than that of tube-end welds, while it was lower than that of bolted connections.

DOI： 10.11273/jssc.32.128_163

Fatigue life evaluation of root failure in welded joints based on displacement around the weld root Open Access

Pradana, EW; Tateishi, K; Hanji, T; Shimizu, M

WELDING IN THE WORLD 2025.12

Publisher：Welding in the World

Unanticipated load transfer in load-carrying cruciform and butt-welded joints with incomplete penetration can initiate fatigue cracks from the weld root. Conventionally, the fatigue life of such joints is assessed using the nominal stress approach. However, this method is often inadequate for geometrically complex joints, particularly when the weld throat nominal stress cannot be clearly defined due to non-uniform stress distribution. Although the effective notch stress (ENS) method provides an alternative, it is computationally demanding and relies on an assumed notch radius which lacks a well-defined physical basis. This study proposes an alternative fatigue evaluation method based on displacement around the weld root, offering a physically meaningful and mesh-insensitive fatigue damage parameter. A linear-elastic finite element model with a 1 mm mesh around the unfused zone was employed to evaluate the displacement at a reference point 1 mm from the weld root. A dataset comprising 398 fatigue test results from specimens with incomplete penetration exhibiting root failure was extracted from the literature to validate the proposed method. A correction factor was introduced to normalize the fatigue damage parameter into a dimensionless form, allowing direct comparisons across specimens of varying sizes and geometries. The relationship between the normalized fatigue damage parameter and fatigue life was presented on logarithmic scales, resulting in the normalized Δd–N curve. This curve not only demonstrates improved predictive accuracy and reliability compared to the conventional S–N curve but also offers a physically interpretable approach applicable to complex welded joint geometries.

DOI： 10.1007/s40194-025-02293-y

Hot-spot stress fatigue strength curves for weld toe on plate edges Open Access

Hanji, T; Tateishi, K; Takeshi, M; Shimizu, M

WELDING IN THE WORLD 2025.11

Publisher：Welding in the World

Hot-spots are classified into two types: Type “a”, which refers to weld toes located on the plate surface, and Type “b”, which refers to weld toes located at the plate edge. In this study, fatigue test data on joint details in which Type “b” cracks occur were collected from 25 published papers, comprising a total of 264 data points across several different joint details. Finite element analysis was performed to compute hot-spot stress, with variations in element type and element size near the reference points used for hot-spot stress calculation. When the data were organized according to the nominal stress range, significant scatter was observed in the S–N diagram due to variations in fatigue strength among different joint details. In contrast, when analyzed based on the 4–8–12 mm method, as recommended in the IIW Designer’s Guide, the scatter was significantly reduced. Taking into account data scatter, the lower limit, which is defined as the mean minus two standard deviations, was 95.4 N/mm2. These findings indicate that fatigue test results for in-plane gusset welded joints, as well as other joint details, can collectively be assessed using the fatigue design curve of FAT90. Additionally, it was confirmed that variations in element size within the range of 1 mm to 4 mm near the reference points, as well as changes in element type, had negligible effects on the hot-spot stress assessment.

DOI： 10.1007/s40194-025-02244-7

ENHANCEMENT OF FATIGUE STRENGTH AT THE ROOT OF OUT-OF-PLANE GUSSET WELDED JOINT BY HIGH FREQUENCY INDUCTION HEATING TREATMENT Open Access

SHIMIZU Masaru, MURAI Kouhei, KANO Suguru, TATEISHI Kazuo, HANJI Takeshi

Kou kouzou rombunshuu Vol. 32 ( 127 ) page： 72 - 82 2025.9

Language：Japanese Publisher：Japanese Society of Steel Construction

In this study, the enhancement of fatigue strength at the weld root in out-of-plane gusset welded joint by high frequency induction heating (IH) treatment was investigated. Fatigue tests were conducted to examine the fatigue strength enhancement by IH treatment. IH treatment was applied to both sides of a boxing weld in the specimens. Test results show 1-grade or more fatigue strength enhancement while the fatigue cracks were generated both from weld root and weld toe in a longitudinal attachment. Additionally, finite element analysis was performed to investigate the fatigue strength enhancement based on effective notch stress. Two million cycle fatigue strength was improved 2.25 times than the welded joint without IH treatment.

DOI： 10.11273/jssc.32.127_72

Extending fatigue life of weld roots in fillet-welded cover plates by installing tap bolt joints

Niwa, Y; Tateishi, K; Hanji, T; Shimizu, M

WELDING IN THE WORLD Vol. 69 ( 8 ) page： 2239 - 2251 2025.8

Publisher：Welding in the World

This study developed a tap bolt joint method with tap holes in both plates as a preventive maintenance method against weld root failure in fillet-welded cover plates. The method aims to reduce the relative displacement between two plates, which is the cause of weld root crack. To evaluate the fatigue strength of the joint and the relative displacement of the plates, fatigue tests and finite element analysis were conducted to examine the fundamental characteristics of tap bolt joints. The results showed that the fatigue strength of the tap bolt joint was distributed around the JSSC-E class under cyclic tensile axial loads and the JSSC-A class under cyclic compressive axial loads and was significantly higher than the JSSC-S class under cyclic shear loads. Furthermore, tap bolt joints were installed in fillet-welded sole plates in plate girders, and their effectiveness was examined through fatigue tests and finite element analysis. The results showed that the tap bolt joint method can extend the fatigue life of the weld root of a sole plate.

DOI： 10.1007/s40194-025-01986-8

Investigation on the rational cut-out shape for fatigue countermeasure in vertical stiffeners of orthotropic steel decks

Shimizu M., Tateishi K., Hanji T., Hasegawa H., Suetsugu H.

IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report page： 2909 - 2916 2025

Publisher：IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report

In orthotropic steel deck, many fatigue cracks have been found at the weld joint between deck plate and vertical stiffeners. As a countermeasure for fatigue, semicircular cut-out has been adopted to reduce the stress concentration around the welded joint between the deck plate and the vertical stiffeners. However, more effective cut-out geometry should be considered in terms of ease of design and fatigue improvement. In this study, the stress reductions were investigated for newly developed slit-like cut-out and sigma-shaped cut-out. In addition, fatigue tests were conducted on the welded joints between the deck plate and the vertical stiffener with sigma-shaped cut-out. The crack initiation life and crack propagation can be prolonged by constructing a sigma-shaped cut-out at the top of the vertical stiffener.

DOI： 10.2749/tokyo.2025.2909

Fatigue Strength of Fillet Welded T-Joints using New Welding Materials

Asano K., Hanji T., Tateishi K., Shimizu M., Kotani Y., Takebuchi T.

IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report page： 2474 - 2482 2025

Publisher：IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report

In this study, fatigue tests and finite element analyses were conducted on T joints using various new welding materials to investigate the effect of enhancing fatigue strength through the application of unconventional welding materials, which are not commonly used in steel bridges. The results revealed that low transformation temperature welding materials reduced the tensile residual stress around the weld, leading to the improvement of fatigue strength. Additionally, it was found that applying additional welding method with a newly developed material for Ar-shielded MIG welding decreased stress concentration at the weld toe, resulting the improvement of fatigue strength.

DOI： 10.2749/tokyo.2025.2474

Fatigue Strength Improvement by Induction Heating against Weld Root Failure in Out-of-Plane Gusset Welded Joints

Kano S., Maeda S., Tateishi K., Hanji T., Shimizu M.

IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report page： 1159 - 1166 2025

Publisher：IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report

This study investigated the improvement of fatigue strength at the weld root in out-of-plane gusset welded joints by induction heating (IH). IH works by locally heating the object with coils energized by high-frequency AC power, which can alter the residual stress distribution. Unlike other methods such as weld toe treatment, IH does not need to treat the potential crack initiation site directly, making it a promising approach for improving fatigue strength at the weld root. The improvement in fatigue strength by IH was verified using fatigue tests under out-of-plane bending loads with a vibration-type fatigue testing machine. Further numerical investigation based on finite element analysis to reproduce the welding and IH clarified the residual stress distributions around the weld.

DOI： 10.2749/tokyo.2025.1159

Evaluation of Through-Thickness Residual Stress at T-Joint Weld Toes Using Slitting Method

Wu Y., Hanji T., Tateishi K., Shimizu M.

IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report page： 2459 - 2465 2025

Publisher：IABSE Symposium Tokyo 2025 Environmentally Friendly Technologies and Structures Focusing on Sustainable Approaches Report

Residual stress in welds is a critical factor influencing the fatigue strength of welded joints. Understanding the residual stress distribution, both on the surface and within the interior of the plates, is essential for improving the accuracy of fatigue strength evaluations in welded joints. This study aims to numerically evaluate the through-thickness residual stress at the weld toe of T-joints using the slitting method. This approach involves welding simulation, slitting simulation, and fracture mechanics to investigate the relationship between the internal residual stress and the strain changes on the plate surface near the weld toe, which occur due to stress relief during the slitting process. The results indicate that the through-thickness residual stress distributions estimated through the slitting method are consistent with those initially present in the welded joint, even under varying conditions such as different initial residual stress distributions, geometrical parameters of the joint (e.g., plate thickness, weld size), and slitting conditions (e.g., slit width and location, cutting depth ratio). Furthermore, this study identifies an optimal slitting strategy, which enhances the accuracy of residual stress evaluation.

DOI： 10.2749/tokyo.2025.2459

Evaluation of Fatigue Damage Ratio for Slotted Tubular Joints of Overhead Transmission Tower with Fatigue Cracks

Stress Measurement for Vortex-induced Vibration of Steel Tubular Tower Member Open Access

SODA Naohiro, TATEISHI Kazuo, HANJI Takeshi, SHIMIZU Masaru

Summaries to Technical Papers of Annual Meeting, Japan Association for Wind Engineering Vol. 2025 ( 0 ) page： 217 2025

Soda, N; Tateishi, K; Hanji, T; Shimizu, M

PROCEEDINGS OF THE 18TH EAST ASIA-PACIFIC CONFERENCE ON STRUCTURAL ENGINEERING AND CONSTRUCTION, VOL 2, EASEC 2024 Vol. 725 page： 502 - 509 2025

Publisher：Lecture Notes in Civil Engineering

To systematically maintain a large number of overhead transmission towers, it is important to understand the mechanism of fatigue failure and its evaluation methods. In this study, we evaluate the fatigue damage ratios for a case involving fatigue cracks in the slotted tubular joints of a testing transmission tower to discuss the applicability of the evaluation method and relevant factors for the fatigue damage ratio. The fatigue damage ratios are calculated using wind data observed near the tower, estimated vortex-induced vibration (VIV), and previous fatigue strength data for slotted tubular joints. The results show that the fatigue damage ratios of horizontal and web members on the north side of the tower, directly exposed to strong winds, exhibited good agreement with the actual fatigue progression. However, the accuracy of the results for members in the cross-arm sections was diminished, primarily due to the stress range induced by VIV nearing the cut-off limit. Additionally, the wind acting on these members were disturbed by the other members located upwind of them. Furthermore, the slenderness ratio of a member with a high fatigue damage ratio was limited to a specific range.

DOI： 10.1007/978-981-96-9917-9_65

Study on the Seismic Capabilities of Various Diameters Oil Storage Tanks Located in an Earthquake Hazard Area Open Access

Hafidz M., Panjaitan A., Afifuddin M., Hasibuan P., Putra R., Bermansyah S., Fauzi M., Haiqal M., Shimizu M.

Iop Conference Series Earth and Environmental Science Vol. 1578 ( 1 ) 2025

Publisher：Iop Conference Series Earth and Environmental Science

Oil storage tanks are essential structures that may be located in an earthquake hazard area. However, the tank's seismic capabilities due to random amplitude (earthquake loading) have not been clarified. This research work elaborates on the seismic capabilities of several different diameter storage tanks, F-6020, F-6021, and F-6022, which are located at PT. Arun in Lhokseumawe City. The research began with a site visit that revealed rusted areas on most surfaces of the roof and tank walls. Next, some FE models of tanks were subjected to Random Variable Amplitude Loading (RVAL). Results showed that the largest diameter tank (F-6022) demonstrated the best dissipated energy ratio (general seismic capability) due to the widest support at the bottom plate to withstand earthquake load. Additionally, the dissipated energy ratio followed a power function trend as displacement increased, regardless of the distinction of tank diameter. Observing the strength-dissipated energy relationships showed that the F-6022 performs the longest plots of strength at the sustenance of dissipated energy due to the largest and most stable hysteretic curve. Furthermore, the smallest diameter tank (F-6020) performed the von Mises stress exceeded the allowable limit, suggesting that seismic reinforcements are necessary for F-6020.

DOI： 10.1088/1755-1315/1578/1/012004

Seismic Performance of the High-Speed Diesel Storage Tank Wall under Several Different Random Variable Amplitude Loadings Open Access

Ayyasi R., Panjaitan A., Afifuddin M., Hasibuan P., Putra R., Bermansyah S., Fauzi M., Haiqal M., Shimizu M.

Iop Conference Series Earth and Environmental Science Vol. 1578 ( 1 ) 2025

Publisher：Iop Conference Series Earth and Environmental Science

A High-Speed Diesel (HSD) oil storage tank is composed of steel and prone to rusting on its walls and roof. This study aims to evaluate the seismic performance of an HSD storage tank in the PT. Arun Gas Lhokseumawe, named F-6018, with a focus on its wall components. The study was initially conducted through a site investigation, which revealed that corrosion was predominantly exposed on the roof and wall surfaces. The seismic analysis was carried out by applying Random Variable Amplitude Loadings (RAs) to the FE models. The results showed that the dissipated energy (general seismic performance) exhibited an escalation trend in the power function at the sustenance of the displacement, regardless of the difference in RA displacement ranges. Additionally, observing the alteration in displacement amplitude of RAs revealed a distinct pattern in the dissipated energy ratio. Increasing amplitudes in RAs revealed that the dissipated energy ratio linearly escalates, and the decreasing amplitude showed a constant function of dissipated energy ratio, together with the additional value of displacement ratio. Furthermore, the analysis also discovered that the equivalent stresses were higher than the allowable values, indicating that the tank requires seismic strengthening.

DOI： 10.1088/1755-1315/1578/1/012001

Structural hot-spot stress approach for toe cracking from plate edge of load-carrying welded attachment

鋼床版横リブ交差部ビード進展き裂に対するデッキプレート上面からの当て板補強に関する解析的検討 Reviewed

寺沢拓哉，清水優，舘石和雄，判治剛，長谷川秀也，末次宏基

鋼構造年次論文報告集 Vol. 32 page： 1 - 9 2024.11

Evaluation of fatigue damage ratio for slotted tubular joints of overhead transmission tower with fatigue cracks Reviewed

Naohiro Soda, Kazuo Tateishi, Takeshi Hanji, Masaru Shimizu

Proceedings of the 18th East Asia-Pacific Conference on Structural Engineering and Construction page： E0054 2024.11

新しい溶接材料を用いたT形すみ肉溶接継手の疲労強度 Reviewed

浅野景太，判治剛，舘石和雄，清水優，小谷祐樹，竹渕敏郎

鋼構造年次論文報告集 Vol. 32 page： 77 - 88 2024.11

AE計測によるルートき裂の検知に関する基礎的検討 Reviewed

清水優，舘石和雄，判治剛

鋼構造年次論文報告集 Vol. 32 page： 39 - 46 2024.11

Extending fatigue life of weld roots in fillet-welded cover plates by installing tap bolt joints Reviewed

Yuichiro Niwa, Kazuo Tateishi, Takeshi Hanji, Masaru Shimizu

The 77th Annual Assembly of International Institute of Welding 2024.7

PREVENTIVE MAINTENANCE MEASURES AGAINST FATIGUE CRACKS AT WELDED JOINTS OF SOLE PLATES OF STEEL BRIDGES Invited Reviewed Open Access

Yuichiro NIWA, Kazuo TATEISHI, Takeshi HANJI, Masaru SHIMIZU

Japanese Journal of JSCE Vol. 80 ( 5 ) page： 1 - 18 2024.5

Hanji, T; Tateishi, K; Rabsel, N; Shimizu, M

WELDING IN THE WORLD Vol. 68 ( 5 ) page： 1201 - 1209 2024.5

Publisher：Welding in the World

The structural hot-spot stress approach is an effective method for assessing welding details when nominal stress is hard to determine due to geometric or loading complexities. Hot spots can be classified into two types: type “a,” which refers to a weld toe located on a plate surface, and type “b,” denoting one located on a plate edge. Previous studies on type “b” hot spots have mainly focused on in-plane gusset welded joints, and the applicability of type “b” hot-spot S-N curves proposed for in-plane gusset joints in IIW to the other details is not well understood. In this study, fatigue tests were conducted with a load-carrying attachment welded on a plate surface, where a crack occurred from a weld toe on the plate edge. The tests were also numerically simulated using finite element analysis. Upon evaluating the test results through the nominal stress, structural hot-spot stress (4, 8, and 12 mm method), and notch stress approaches, it was found that all the data lie above FAT71 for nominal stress, FAT100 for hot-spot stress, and FAT225 for effective notch stress.

DOI： 10.1007/s40194-024-01724-6

Evaluation of Thickness Effect on Fatigue Life Variation of Longitudinal Welded Gusset Joint

Putri, CA; Tateishi, K; Shimizu, M; Hanji, T

INTERNATIONAL JOURNAL OF STEEL STRUCTURES Vol. 24 ( 2 ) page： 246 - 255 2024.4

Publisher：International Journal of Steel Structures

Numerous studies have been conducted regarding the fatigue strength of longitudinal welded gusset joints. Most studies employed relatively small specimens. Thus, this study aims to evaluate the variation of fatigue life of longitudinal welded gusset joints by using the probabilistic fracture mechanics approach, particularly for larger specimens. Although some studies claimed that lower fatigue strength is found in the thicker main plate specimens, however only a limited number of fatigue test was conducted. A probabilistic approach was employed to conquer the shortfall. In this study, fatigue crack propagation analysis was performed on the main plate thicknesses of 12, 40, and 60 mm to evaluate the effect of main plate thickness on the fatigue life of the joints. Then, a probabilistic approach is given to investigate the variation of fatigue life of the joint. In addition, fatigue tests were carried out to investigate the crack propagation behavior on larger specimens. A significant decrease in fatigue life was observed by the increase of the main plate thickness from 12 to 40 mm, however, no further decrease thereafter. The fatigue strength of longitudinal welded gusset joints with the main plate thickness of 12 mm was appertained to category F in the JSSC design curve. Meanwhile, the fatigue strength of longitudinal welded gusset joints with the main plate thickness of 40 and 60 mm falls into category G in JSSC. This condition was also confirmed by the fatigue test results, where both specimens were classified as category G in JSSC.

DOI： 10.1007/s13296-024-00812-z

Numerical simulation of fatigue crack propagation and repair with drilled hole in trough-girder bridges Reviewed

Takeshi Hanji, Kazuo Tateishi, Miki Shibata, Masaru Shimizu, Makoto Yamaguchi, Yuichiro Niwa

The 77th Annual Assembly of International Institute of Welding page： XIII-3083-2024 2024.4

タップボルト継手の疲労強度および材間相対変位の評価 Reviewed Open Access

丹羽雄一郎，舘石和雄，判治剛，清水優

鋼構造論文集 Vol. 31 ( 121 ) page： 115 - 126 2024.3

鋼床版Uリブ・デッキプレート溶接継手におけるルートの局部応力による疲労強度評価 Reviewed Open Access

清水優，判治剛，内田大介，服部雅史，吉田黎

鋼構造論文集 Vol. 31 ( 121 ) page： 72 - 87 2024.3

FATIGUE EVALUATION OF U-RIB TO DECK WELD JOINT IN ORTHOTROPIC STEEL DECK BASED ON LOCAL STRESS AT WELD ROOT Reviewed Open Access

SHIMIZU Masaru, HANJI Takeshi, UCHIDA Daisuke, HATTORI Masafumi, YOSHIDA Rei

Kou kouzou rombunshuu Vol. 31 ( 121 ) page： 72 - 87 2024.3

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Steel Construction

Many fatigue tests have been conducted to reproduce a root crack in deck-to-U rib welded joints and to investigate its fatigue durability. Nevertheless, no unified fatigue strength evaluation method for the root crack has been established. In this study, total of 154 fatigue test results were reproduced in the analysis to obtain artificial notch stress at weld root, and the test results were rearranged by the notch stress. Two million cycles fatigue strength and its standard deviation based on the notch stress are discussed in this paper. Two million cycles fatigue strength tends to be higher when the mean stress in cyclic loading is in compression. By correcting the test results with the stress ratio, all test results located around a unified fatigue strength curve.

DOI： 10.11273/jssc.31.121_72

EVALUATION OF FATIGUE STRENGTH OF TAP BOLT JOINT AND RELATIVE DISPLACEMENT OF PLATES Reviewed Open Access

NIWA Yuichiro, TATEISHI Kazuo, HANJI Takeshi, SHIMIZU Masaru

Kou kouzou rombunshuu Vol. 31 ( 121 ) page： 115 - 126 2024.3

Language：Japanese Publisher：Japanese Society of Steel Construction

In this study, as a preventive maintenance method against root cracks at welded joints of cover plates, the tap bolt joint method with tap holes in both plates was proposed based on the concept of reducing the relative displacement between plates which is the cause of root crack initiation. As a fundamental study on the tap bolt joint, the fatigue strength of the joint and relative displacement of plates were evaluated by fatigue tests and FEA. It was revealed that the fatigue strengths were distributed around JSSC-E to F classes under cyclic tensile axial loads, JSSC-A class under cyclic compressive axial loads and much higher than JSSC-S class under cyclic shear loads.

DOI： 10.11273/jssc.31.121_115

疲労耐久性に優れた鋼床版垂直補剛材上端部の切欠き形状の検討 Reviewed Open Access

清水優，舘石和雄，判治剛，金子大介，末次宏基

構造工学論文集A Vol. 70A page： 458 - 469 2024.3

疲労き裂が発生した鉄塔部材の鋼管割込み継手に対する疲労損傷比の評価 Reviewed Open Access

早田直広，舘石和雄，判治剛，清水優

構造工学論文集A Vol. 70A page： 521 - 534 2024.3

鋼製橋脚角溶接部の面外曲げ作用による破壊過程と照査法の検討 Reviewed Open Access

真木有岳，川東龍則，舘石和雄，清水優，萩原直樹，稲熊唯史

構造工学論文集A Vol. 70A page： 577 - 588 2024.3

Failure processes and study on verification methods for corner weld joint of steel pier due to out-of-plane bending Reviewed Open Access

Maki Aritake, Kawahigashi Tatsunori, Tateishi Kazuo, Shimizu Masaru, Hagiwara Naoki, Inaguma Tadashi

Journal of Structural Engineering, A Vol. 70A ( 0 ) page： 577 - 588 2024.3

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers

Several corner weld failures of steel piers during large earthquakes have been attributed to the rupture of corner welds with unwelded section. First, both of tensile tests and finite element analysis of the corner weld model were conducted parametrically in order to clarify the fracture mechanism of corner welds. As a result of the study, a fracture process was observed in which the cracks firstly occurred in the inner corner welds and then in the outer welds. Next the simplified verification method for the corner weld was also investigated. As a result of the investigation, it was found that the approximate bending strength can be calculated without considering the effects of stress concentration. In the future, we plan to investigate structural models through experiments and finite element analysis.

DOI： 10.11532/structcivil.70A.577

Evaluation of fatigue damage ratio for slotted tubular joints of steel tower members with fatigue cracks Reviewed Open Access

Soda Naohiro, Tateishi Kazuo, Hanji Takeshi, Shimizu Masaru

Journal of Structural Engineering, A Vol. 70A ( 0 ) page： 521 - 534 2024.3

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers

Fatigue cracks were initiated at slotted tubular joints in a testing overhead transmission tower. It was estimated that the cracks were caused by vortex induced vibration (VIV). In this study, the fatigue evaluation for steel tub ular memb ers in the tower was conducted with observed wind data and a response estimation method for VIV. The fatigue damage ratios of horizontal members and web members on the north side of the tower were good agreement with the actual failure state. However, those of members in the cross arm section were low accuracy because stress ranges were similar to the cut-off limit and wind was disturbed by upwind members Moreover, it was clarified that slenderness ratio of a member with a high fatigue damage ratio was limited to a certain range.

DOI： 10.11532/structcivil.70A.521

Examination of the notch geometry effective in fatigue durability constructed to the top of vertical stiffeners in orthotropic steel deck Reviewed Open Access

Shimizu Masaru, Tateishi Kazuo, Hanji Takeshi, Kaneko Daisuke, Suetsugu Hiroki

Journal of Structural Engineering, A Vol. 70A ( 0 ) page： 458 - 469 2024.3

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers

In orthotropic steel deck, many fatigue crack has been found at the weld joint between deck plate and vertical stiffeners. As a counter measure for the fatigue, semi-circular notch has been adopted to reduce the stress concentration around boxing weld. However, more effective notch geometry should be considered from viewpoint of ease of construction and fatigue improvement. In this study, reduction of stress and stress intensity factor were investigated for newly developed slit-like notch and sigma-shaped notch. In addition, fatigue tests were performed for the weld joints between deck plate and vertical stiffener with sigma-shaped notch. The crack initiation life and crack propagation can be extended by constructing sigmashaped notch at the top of vertical stiffener.

DOI： 10.11532/structcivil.70A.458

PREVENTIVE MAINTENANCE MEASURES AGAINST FATIGUE CRACKS AT WELDED JOINTS OF SOLE PLATES OF STEEL BRIDGES Open Access

NIWA Yuichiro, TATEISHI Kazuo, HANJI Takeshi, SHIMIZU Masaru

Japanese Journal of JSCE Vol. 80 ( 5 ) page： n/a 2024

Language：Japanese Publisher：Japan Society of Civil Engineers

Many cases of fatigue cracks at welded joints of sole plates in steel bridges have been reported. And the causes of the cracks generation and countermeasures have been studied. However, the study has so far mainly focused on corrective maintenance, and practical preventive maintenance measures have not been established. In this study, focusing on the toe crack and root crack that generates at welded joint of sole plate, preventive maintenance measures by peening treatment and tap bolts were studied by FEA and fatigue tests. As a result, it was clarified that the peening treatment could improve the fatigue strength of the weld toe of sole plate under the conditions of compressive stress acting on the weld, and the method using tap bolts could extended the fatigue life of the weld root of sole plate.

DOI： 10.2208/jscejj.23-00234

Fatigue strength evaluation by measurable stresses for root cracks in U-rib to deck welded joints of orthotropic steel decks

AE計測によるルートき裂の検知に関する基礎的検討 Reviewed

清水優, 舘石和雄, 判治剛

鋼構造年次論文報告集 Vol. 32 page： 39 - 46 2024

鋼床版横リブ交差部ビード進展き裂に対するデッキプレート上面からの当て板補強に関する解析的検討 Reviewed

清水優, 舘石和雄, 判治剛

鋼構造年次論文報告集 Vol. 32 page： 1 - 9 2024

未溶着部を有する鋼製橋脚角溶接部の低サイクル疲労による破壊形態の推定 Reviewed

清水優，舘石和雄，判治剛，村上智明，萩原直樹，稲熊唯史，真木有岳

鋼構造年次論文報告集 Vol. 31 page： 160 - 170 2023.11

新しいリベットにより取替え補修した継手の力学的挙動に関する研究 Reviewed

柴田美希，判治剛，舘石和雄，清水優，長坂康史，竹渕敏郎

鋼構造年次論文報告集 Vol. 31 page： 409 - 416 2023.11

未溶着部を有する鋼製橋脚角溶接部の低サイクル疲労による破壊形態の推定 Reviewed

清水優, 舘石和雄, 判治剛, 村上智明, 萩原直樹, 稲熊唯史, 真木有岳

鋼構造年次論文報告集 Vol. 31 page： 160 - 170 2023.11

新しいリベットにより取替え補修した継手の力学的挙動に関する研究 Reviewed

柴田美希, 判治剛, 舘石和雄, 清水優, 長坂康史, 竹渕敏郎

鋼構造年次論文報告集 Vol. 31 page： 409 - 416 2023.11

Hattori, M; Tateishi, K; Hanji, T; Shimizu, M

WELDING IN THE WORLD Vol. 67 ( 9 ) page： 2273 - 2282 2023.9

Publisher：Welding in the World

Root cracks initiating from U-rib to deck welded joints of orthotropic steel deck bridges have become a problem for maintenance. Some fatigue strength evaluation methods for root cracks based on local stress criteria have been proposed, such as the effective notch stress method, but these methods cannot evaluate fatigue strength directly from the measurable response values of the structure. In this study, the evaluation method of crack initiation by measurable stresses was investigated by fatigue tests and FE analysis for both deck and bead propagation-type cracks, which are root cracks in U-rib to deck welded joints of orthotropic steel decks. As a result of the study, the relationship between the stress of weld root and the fatigue life was obtained by using the fillet shaped notch stress as the evaluation stress, and the S-N curve for the evaluation stress was proposed. And a method to estimate the evaluation stress of the root from the measurable stresses at four points was proposed. It was confirmed that the error of the proposed estimation method was generally within 10%. As a validation of the estimation method, it was confirmed that the fatigue test results could be properly evaluated.

DOI： 10.1007/s40194-023-01568-6

Study on unsymmetrical steel gable frames constructed from built up columns and rafters

Panjaitan A., Hasibuan P., Shimizu M.

Aip Conference Proceedings Vol. 2711 2023.5

Publisher：Aip Conference Proceedings

Steel gable frames is a structure type widely used for warehousing. Such structure is characterized by the long span roof truss and minimum number of columns to optimaze storage capacity. A gable frame is commonly composed by single profile of rafter and column to ensure the compactness of sectional area. However, in many cases, the capacity of single profile cannot be met and a gable frame has to be established from built up profile sections. This paper analytically investigated a design of gable frame constructed from built up profiles with considering unsymmetrical slopes in rafter. Three different unsymmetrical steel gable frames (SGF) with different rafter slope at the left and right side were provided. For each model, the left rafter has gentler slope than the right rafter. The models were named according to the left rafter slope: SGF 10 (10-degree slope), SGF 20 (20-degree slope), and SGF 30 (30-degree slope), respectively. First, the model of gable was established and load combinations were applied. The internal forces obtained from analysis were used to design the gable frames. The design referred to SNI-1729-2020. This study revealed that SGF 30 experienced the lowest internal forces and resulted the smallest sectional area for rafters and columns. Furthermore, torsional effects were also negligible in all steel gable frames. Investigation on three gable frames indicated that SGF 30 which has the steeper slopes exhibited the best performance than the SGF 10 and SGF 20.

DOI： 10.1063/5.0137293

鋼橋ソールプレート溶接部の発生応力推定に関する解析的検討 Reviewed Open Access

丹羽雄一郎, 舘石和雄, 判治剛, 清水優

構造工学論文集A Vol. 69A page： 568 - 578 2023.4

Analytical study on estimation of stress generated in sole plate welds of steel bridges Reviewed Open Access

Niwa Yuuichirou, Tateishi Kazuo, Hanji Takeshi, Shimizu Masaru

Journal of Structural Engineering, A Vol. 69A ( 0 ) page： 568 - 578 2023.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers

In this study, a screening method for the fatigue cracks around the sole plate welds in preventive maintenance was studied based on measurements of the actual bridge and finite element analysis. First, the results of the actual bridge measurements show that the compressive stress at the lower surface of the lower flange increases as closer to the sole plate welds. Next, by parametric study with plate thickness, it was shown that the hot-spot stress range at the front fillet weld toe between the lower flange and sole plate can be estimated by the local cross-sectional area and the horizontal reaction force. Based on the results, a formula for the hot-spot stress range at the front fillet weld toe between the lower flange and sole plate was proposed to screen locations at high risk against fatigue.

DOI： 10.11532/structcivil.69A.568

Fatigue Crack Growth Characteristics of Several Kinds of Structural Steels Under Low-Cycle Fatigue Loading Reviewed International coauthorship

Jiang Chao, Hanji Takeshi, Tateishi Kazuo, Shimizu Masaru

INTERNATIONAL JOURNAL OF STEEL STRUCTURES Vol. 23 ( 1 ) page： 37 - 49 2023.2

既設鋼床版のUリブ・デッキプレート溶接部に対する床版下面からの疲労対策 Reviewed Open Access

服部雅史, 舘石和雄, 判治剛, 清水優

土木学会論文集 Vol. 79 ( 1 ) page： 1 - 20 2023.1

FATIGUE COUNTERMEASURES FOR U-RIB TO DECK WELDED JOINTS FROM UNDERSIDE OF EXISTING ORTHOTROPIC STEEL DECKS Reviewed Open Access

HATTORI Masafumi, TATEISHI Kazuo, HANJI Takeshi, SHIMIZU Masaru

Japanese Journal of JSCE Vol. 79 ( 1 ) page： 1 - 20 2023.1

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers

This paper proposes a countermeasure for fatigue cracks that propagate from the weld root of U-rib to deck welded joints to the deck plate or weld bead of orthotropic steel deck. Specifically, the lower flange of the U-rib is removed and the U-rib and deck plate welds are welded from the inside of the U-rib as a countermeasure method. First, to confirm the feasibility of this countermeasure with structural changes, the load-bearing capacity, workability of welding, and effects on asphalt pavement were verified. Next, changes in the local stress properties of the focused welds and other areas due to the countermeasures were confirmed by finite element analysis. Finally, the fatigue durability of the countermeasure was determined by fatigue tests.

DOI： 10.2208/jscejj.22-00231

Fatigue evaluation for root cracks in U-rib to deck welded joints of orthotropic steel decks

Hattori M., Tateishi K., Hanji T., Shimizu M.

Bridge Safety Maintenance Management Life Cycle Resilience and Sustainability Proceedings of the 11th International Conference on Bridge Maintenance Safety and Management Iabmas 2022 page： 2123 - 2130 2023

Publisher：Bridge Safety Maintenance Management Life Cycle Resilience and Sustainability Proceedings of the 11th International Conference on Bridge Maintenance Safety and Management Iabmas 2022

This paper examines a fatigue evaluation method for the cracks in the weld joints between a U-rib and a deck plate in orthotropic steel bridge decks. The crack initiates from the weld root and propagates into the deck plate or the weld bead. Fatigue tests and FE analyses were conducted in order to examine the local stresses available for fatigue assessment, and to propose a method to estimate them from some reference stresses around the weld joint. In addition, based on fatigue crack propagation analyses, a method to predict the crack propagation path was proposed.

DOI： 10.1201/9781003322641-263

Numerical investigation of fatigue crack propagation behavior in trough-girder bridges Open Access

Putra Teuku Habil, Hanji Takeshi, Tateishi Kazuo, Shimizu Masaru, Yamaguchi Makoto, Niwa Yuuichirou

Journal of Structural Engineering, A Vol. 69A ( 0 ) page： 558 - 567 2023

Language：English Publisher：Japan Society of Civil Engineers

Fatigue cracks have been observed from welded joints of end diaphragms at steel railway troughgirder bridges due to vertical movement behavior at their supports that is not expected during the design phase. Since this movement behavior is complicated and varies on each bridge depending on the damage around the support, effective retrofitting methods against the crack have not been established yet. In this study, the influence of the vertical movement tendency at the bridge supports on the crack initiation location and crack propagation behavior at the end diaphragm was investigated through numerical simulation. The result indicated that the relative displacement at the bedplate affected the crack initiation location and crack propagation path, and that the stress intensity factor tended to gradually decrease after propagating a certain length.

DOI： 10.11532/structcivil.69a.558

Fatigue strength enhancement of welded joints in existing steel bridges using high-frequency mechanical impact treatment

Prediction of Residual Stress Induced by High-Frequency Mechanical Impact (HFMI) Treatment

HANJI Takeshi, MASUI Shunsuke, TATEISHI Kazuo, SHIMIZU Masaru, ONO Shuichi

Preprints of the National Meeting of JWS Vol. 2023s ( 0 ) page： 180 - 181 2023

Hanji T., Tateishi K., Kano S., Shimizu M.

Publisher：Bridge Safety Maintenance Management Life Cycle Resilience and Sustainability Proceedings of the 11th International Conference on Bridge Maintenance Safety and Management Iabmas 2022

In this study, the effect of the stress state of a welded joint during application of high-frequency mechanical impact (HFMI) treatment on the resulting fatigue strength was investigated through fatigue tests and finite element analysis. A high-frequency impact treatment tool was used as the HFMI device. Longitudinal attachment welded joints were treated under a state in which a static load was applied and subsequently tested under a constant stress amplitude with stress ratios of 0 or 0.5. In addition, residual stress measurements and finite element analysis simulating welding and treatment processes were performed. The results indicate that the HFMI treatment is beneficial even when applied under a static tensile load, as the resulting compressive residual stresses are similar regardless of the stress state in the joint during treatment, meaning that the HFMI is applicable to existing structures.

DOI： 10.1201/9781003322641-262

Effect of UHPFRC Overlay on Fatigue Cracks Propagating from U-rib Welds of Orthotropic Steel Decks Reviewed

Hattori Masafumi, Tateishi Kazuo, Hanji Takeshi, Shimizu Masaru

INTERNATIONAL JOURNAL OF STEEL STRUCTURES Vol. 22 ( 6 ) page： 1808 - 1816 2022.12

Fatigue Strength of Deck-to-Rib Welded Joint And Correlation to Full-Scale Orthotropic Steel Deck System Reviewed

Masaru SHIMIZU, Takayuki UCHIDA, Kazuo TATEISHI, Takeshi HANJI, Masafumi HATTORI

Vol. 30 page： 297 - 305 2022.11

Fatigue Strength of Deck-to-Rib Welded Joint And Correlation to Full-Scale Orthotropic Steel Deck System Reviewed

Masaru SHIMIZU, Takayuki UCHIDA, Kazuo TATEISHI, Takeshi HANJI, Masafumi HATTORI

Vol. 30 page： 297 - 305 2022.11

コーナープレート切欠き部の疲労耐久性とICR処理による延命効果 Reviewed Open Access

清水優, 舘石和雄, Shinta Ayuningtyas, 判治剛, 高田佳彦, 熊澤美早, 山口樹, 岡本亮二, 西芝貴光

構造工学論文集 Vol. 68A page： 580 - 590 2022.4

Fatigue durability of cut-out in corner plate and fatigue life extension by ICR treatment Reviewed Open Access

Shimizu Masaru, Tateishi Kazuo, Ayuningtyas Shinta, Hanji Takeshi, Takada Yoshihiko, Kumazawa Misa, Yamaguchi Itsuki, Okamoto Ryoji, Nishishiba Takamitsu

Journal of Structural Engineering, A Vol. 68A ( 0 ) page： 580 - 590 2022.4

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Society of Civil Engineers

Corner plates are often welded at the intersection between web and flange in steel box girders. As a measure against fatigue in the weld joint between corner plate and lateral rib, the end of corner plate was cut-out in U-shape. Nevertheless, fatigue cracks have been generated from exposed root on the cut-out surface. In this study, fatigue strength and fatigue life improvement by ICR treatment were investigated. The fatigue strength of the weld joint was JSSC-G class. Application of ICR treatment improves the fatigue strength by 1 grade or more, and the fatigue limit was improved as 59 N/mm2 or more. Furthermore, stress concentration factor around exposed root was investigated by finite element analysis.

DOI： 10.11532/structcivil.68A.580

Effect of static load during HFMI treatment on fatigue strength and residual stress field of longitudinal atachment welded joints (Nov, 10.1007/s40194-021-01208-x, 2021) Open Access

Effect of static load during HFMI treatment on fatigue strength and residual stress field of longitudinal atachment welded joints Reviewed

Hanji Takeshi, Tateishi Kazuo, Kano Suguru, Shimizu Masaru

WELDING IN THE WORLD Vol. 66 ( 4 ) page： 685 - 697 2022.4

Prediction of residual stress induced by high-frequency mechanical impact treatment Reviewed Open Access

Hanji Takeshi, Tateishi Kazuo, Kano Suguru, Shimizu Masaru

WELDING IN THE WORLD Vol. 66 ( 4 ) page： 709 - 720 2022.4

Hanji, T; Tateishi, K; Kano, S; Shimizu, M

WELDING IN THE WORLD Vol. 66 ( 4 ) page： 845 - 845 2022.4

Failure Probability for Fatigue Crack in Web Plate of Bridge Girder Reviewed International coauthorship

Putri Cut Atika, Tateishi Kazuo, Shimizu Masaru, Hanji Takeshi

INTERNATIONAL JOURNAL OF STEEL STRUCTURES Vol. 22 ( 1 ) page： 42 - 55 2022.2

Study on Fatigue Durability of Steel Box Girder Corner Plate Weld with Peening Reviewed

Takamitsu Nishishiba, Yoshihiko Takada, Misa Kumazawa, Ryoji Okamoto, Kazuo Tateishi, Shimizu Masaru

Conference: IABSE Symposium, Prague 2022: Challenges for Existing and Oncoming Structures page： 783 - 791 2022.1

FATIGUE EVALUATION FOR ROOT CRACKS IN U-RIB TO DECK WELDED JOINTS OF ORTHOTROPIC STEEL DECKS BASED ON FIELD MEASUREMENTS Open Access

HATTORI Masafumi, TATEISHI Kazuo, HANJI Takeshi, SHIMIZU Masaru

Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)) Vol. 78 ( 2 ) page： 287 - 300 2022

Language：Japanese Publisher：Japan Society of Civil Engineers

This paper examines application of a fatigue evaluation method for the cracks in the weld joints between a U-rib and a deck plate in orthotropic steel bridge decks. Field measurements were conducted in two sections with different crack initiation trends, and a method was proposed to obtain the cumulative fatigue damage ratio from the measurement results and routinely obtained data such as temperature and traffic volume. In addition, the validity of the evaluation of crack initiation and propagation direction by the developed evaluation method is verified by comparing with the actual crack situation, and a method to screen out the priority inspection and investigation area is proposed.

DOI： 10.2208/jscejseee.78.2_287

Study on Fatigue Durability of Steel Box Girder Corner Plate Weld with Peening

Nishishiba T., Takada Y., Kumazawa M., Okamoto R., Tateishi K., Shimizu M.

IABSE Symposium Prague 2022 Challenges for Existing and Oncoming Structures Report page： 783 - 791 2022

Publisher：IABSE Symposium Prague 2022 Challenges for Existing and Oncoming Structures Report

Corner plates are sometimes added to the web-to-flange joints of box girder bridges by welding on a single side to increase stiffness. In the case of the Minatogawa Bridge on the Hanshin Expressway, a steel box girder with low girder height and corner plate was used to reduce the weight of the superstructure. In this bridge, many fatigue cracks were observed in the welds of the corner plates. As a crack suppression measure, the end of corner plate was cut-out in U-shape. Although the stress concentration relaxation reduced the risk of crack initiation, the risk of crack initiation starting from the un-welded area still remains. In this study, we focused on peening as a countermeasure to improve the fatigue endurance. As a result, it was confirmed that peening to the un-welded area was effective in improving the fatigue endurance.

DOI： 10.2749/prague.2022.0783

Residual stress and fatigue strength of longitudinal attachment joints improved by HFMI treatment under static load Open Access

Hanji Takeshi, Kano Suguru, Tateishi Kazuo, Shimizu Masaru

Journal of Structural Engineering, A Vol. 68A ( 0 ) page： 591 - 602 2022

Language：Japanese Publisher：Japan Society of Civil Engineers

In this study, the effect of the stress state of a welded joint during application of high-frequency mechanical impact (HFMI) treatment on the resulting fatigue strength was investigated. Longitudinal attachment joints were treated under a state in which a static load was applied and subsequently tested under a constant stress amplitude with stress ratios of 0 or 0.5. The test results indicated that enhanced fatigue strength can be achieved even under a high stress ratio when the joint is treated under the minimum stress of fatigue loading. In addition, residual stress measurements and finite element analysis simulating a treatment process indicated that the magnitude of compressive residual stress introduced to a weld toe is similar regardless of the stress state in the joint during treatment.

DOI： 10.11532/structcivil.68a.591

RETARDATION OF FATIGUE CRACK GROWTH BY CORROSION ACCELERATOR INJECTION Open Access

PUTRI Cut Atika, TATEISHI Kazuo, SHIMIZU Masaru, HANJI Takeshi

Kou kouzou rombunshuu Vol. 28 ( 112 ) page： 112_111 - 112_116 2021.12

Language：English Publisher：Japanese Society of Steel Construction

In this study, fatigue crack growth was retarded by injecting corrosion accelerator, Nitric acid (HNO3), into the crack to induce corrosion. The presence of the corrosion products is expected to reduce the crack opening width and act as a wedge to control the crack closure. Fatigue tests were carried out on the compact tension (CT) specimens. The test revealed that the corrosion process due to HNO3 injection ends after 24 hours. Then, the reduction in crack opening displacement range can be observed. Retardation in the crack growth was observed regardless of the load range and the effective stress intensity factor range (ΔKeff) at injection. Meanwhile, the retardation level tends to be affected by the ΔKeff and crack length at injection.

DOI： 10.11273/jssc.28.112_111