Professor Kojiro UENAKA, Dr. Eng.
Department of Civil EngineeringKobe City College of Technology(KCCT)
Gakuenhigashimachi 8-3, Nishi, Kobe, 6512194, Japan
Email: uenaka at mark kobe-kosen.ac.jp
http://www.kobe-kosen.ac.jp/~uenaka/index_e.html
http://www.kobe-kosen.ac.jp/~uenaka/index.html(in Japanese)
1. Personal History
- [1995]Bachelor of Engineering(Civil Engineering), Kinki University, Japan
- [1997]Master of Engineering(Civil Engineering), Osaka City University, Japan
- [2000]Doctor of Engineering(Civil Engineering), Osaka City University
- [2000]Research Associate of Kobe City College of Technology, Japan
- [2001]Lecturer of Kobe City College of Technology
- [2005]Associate Professor of Kobe City College of Technology
- [2017-present]Professor of Kobe City College of Technology
- [2022-2023]Head of the Department of Civil Engineering
The Title of Doctoral Thesis
Experimental Study on Shear Bond Characteristics of Embossed Steel Plates for Steel-Concrete Composite Members(Doctor of Engineering, Osaka City University, 2000)2.Research Field
Keywords: Steel-Concrete Composite Structures, Tubular Structures, Lighter Structural Members, Shear Connectors
2.1 Experimental Study on Shear-bond Characteristics of Embossed Steel Plates for Steel Concrete Composite Members(Mostly Doctoral Thesis)
In Japan, there have been developed various embossed steel products for composite constructions, for instance, checkered of ribbed plates and tubes with inner or outer embossed surface to improve shear bond characteristics between steel and concrete for composite members. In particular, it should be noted that these embossments are automatically made thorough a hot rolling process. The shear bond strength is not clear enough to apply the practical design method for the composite constructions.
This study aims to investigate shear bond characteristics of two embossed steel plates experimentally. First, pull-out testing method under constant lateral pressure between the plates and the core concrete was conducted. From the pull-out test results, the empirical equation of shear bond strength of embossed steel plates with lateral pressure has been proposed. Secondly, the shear bond test subjected to bending-shear was performed. From the results, the validity of the equation proposed by above-mentioned pull-out test without the lateral pressure was confirmed. Comparison of pull-out test, beam test and an ordinary push out test methods are also discussed.
In addition, symmetrically four-point loading test on twenty three simply supported open-sandwich beams consisting of RC slab and embossed or plain steel plate with headed studs was performed. Ultimate loading capacities and failure modes were examined in relation to the types of steel plates, stud spacing and shear span ratios. Obtained failure modes are divided into three types, which were diagonal shear failure, bending failure and shear bond failure. Methods to predict the ultimate strength of the open-sandwich composite beam based upon the three failure modes are provided.
Keywords: embossed steel plates, shear bond, pull-out test, push-out test, beam test, open-sandwich beam
2.2 Systematic Study on Mechanical Behavior of Concrete Filled Double Skin Tubular Members
Concrete filled double skin tubular, CFDST, member has a hollow section consisting of double concentric steel tubes and sandwiched filled concrete. It is consequently lighter than an ordinary concrete filled tubular, so-called CFT, member with a solid section. CFDST member also holds the same mechanical behavior of CFT member. In addition, structural application of CFDST leads own weight reduction by virtue of its hollow section. Therefore, CFDST member may be advantageous to seismic resistant structures such as high raise bridge pier owing to mitigate seismic force against foundation.
The aim of this work is to investigate mechanical behavior under various loading conditions, namely, centric loading, pure bending moment and bending-shear capacities of the CFDST members experimentally. Biaxial elasto-plastic stress behavior of inner and outer tubes under plane stress conditions was also discussed. Effect of two parameters being inner-to-outer diameter ratio and diameter-to-thickness ratio on various mechanical behavior of CFDST is mainly discussed.
Keywords: concrete filled double steel tubular members, concrete filled steel tubular members, inner-to-outer diameter ratios, confinement stress.
2.3 Shear Bond Characteristics of the Hollow Shear Connectors
The composite slab consisting of channel- or half pipe-welded bottom steel plates with headed stud connectors and RC slab(LWC slab in abbreviation) has been proposed. The welded channel or half pipe inside hollow section of LWC slab can reduce its self weight in comparison with an ordinary steel concrete composite slab.
Purpose of present study is to investigate shear bond characteristics of the channel or the half pipe steel through a push out testing method. Testing parameters selected are web height-to-thickness ratio for the channel and diameter-to-thickness ratio for half pipe. As a result, shearing capacities of channel and half pipe hold a good deformability in comparison with headed stud connector. With respect to the channel specimens, observed failure modes were both compressive failure of concrete and buckling of the channel web. Furthermore, method to predict the channel's shear bond strength based upon web height-to-thickness ratio was mentioned. As to the half pipe specimens, shearing strength is affected by diameter-to-thickness ratios. The shear bond strength under direct shear increases as the diameter-to-thickness ratio decreases.
Keywords: lightweight steel-concrete composite slab, the channel shear connector, half pipe shear connector, push out test, shear bond
2.4 Mechanical Behavior of Concrete Filled Elliptical/Oval Steel Tubular Members
A concrete filled elliptical/oval steel tubular, CFEST in abbreviation, member consists of elliptical/oval hollow steel tube and in-filled concrete. The CFEST member is a family of concrete filled steel tubular, CF(S)T, member which holds high deformability and large toughness under seismic action.
This study aims to investigate mechanical characteristics of CFEST member with large diameter-to-thickness ratio experimentally. Selected testing parameters are diameter-to-thickness ratio of elliptical/oval steel tube and aspect ratios of that. The ultimate capacities of CFEST member is strongly affected by diameter-to-thickness ratio of the tubes.
Keywords: concrete filled elliptical/oval steel tubular, concrete filled steel tubular, diameter-to-thickness ratio, aspect ratio
2.5 Mechanical Behavior of Lightweight Cocnrete Filled Steel Tubular Members
Lightweight structural concrete(LC) consists of cement, water and fine and coarse artificial structural aggregates. The LC is lighter than an ordinary aggregate concrete(NC), however, tensile strength and Young's modulus of the LC is smaller than those of the NC.
Present research aims to investigate mechanical behavior of LC filled steel tubular, L-CFT member, the lightweight concrete in which is reinforced by surrounding steel tube. Compressive and bending-shear behavior of L-CFT is compared with that of normal concrete filled concrete steel tube, N-CFT, member. Method to predict ultimate capacities of L-CFT member is mainly discussed.
Keywords:lightweight concrete, L-CFT, large diameter-to-thickness ratio
3. Teaching Commitments
- Advanced Structural Mechanics II(for advanced course students)
- Structural Mechanics I(for second-term students)
- Structural Mechanics IV(for fifth-term students)
- Fundamentals of Information Technology(for first-term students)
- Practice and Experiment in Civil Engineering(for third- and fourth-terms students)
4. Memberships
- A member of Japan Society of Civil Engineers(JSCE)
- A member of Japan Concrete Institute(JCI)
5. Selected Papers
- Uenaka, K. & Mizukoshi, M.(2021): Lightweight Concrete Filled Steel Tubular Beam under Bending-shear, Structures - Reseach Journal of The Institution of Structural Engineers, 30, 659-666.
- Uenaka, K.(2021): Concrete Filled Double Skin Square Tubular Stub Columns subjected to Compression Load, Structural Engineering and Mechanics, 77(6), 745-751.
- Uenaka, K.(2018): Concrete Filled Double Skin Tubular Deep Beam Having Outer Circular and Inner Square Sections under Bending-Shear, Structures - Research Journal of The Institution of Structural Engineers, 14, 313-321.
- Uenaka, K. & Tsunokake, H.(2017): Concrete Filled Square Steel Tubular Deep Beam subjected to Bending-shear, Materials science, Engineering and Chemistry, 138, doi: 10.1051/matecconf/201713802014.
- Uenaka, K. & Tsunokake, H.(2017): Behavior of Concrete Filled Elliptical Steel Tubular Deep Beam under Bending-shear, Structures -Research Journal of The Institution of Structural Engineers, 10, 89-95.
- Uenaka, K.(2016): Experimental Study on Concrete Filled Double Square Skin Tubular Columns under Centric Loading, Proceeding of the 7th International Conference of Asian Concrete Federation, Asian Concrete Federation, Hanoi, Vietnam.
- Uenaka, K.(2016): CFDST Stub Columns Having Outer Circular and Inner Square Sections under Compression, Journal of Constructional Steel Research, 120, 1-7.
- Uenaka, K. & Tsunokake, H.(2016): Concrete Filled Elliptical Steel Tubular Members with Large Diameter-to-thickness Ratio subjected to Bending, Structures -Research Journal of The Institution of Structural Engineers , 5, 58-66.
- Uenaka, K. & Higashiyama, H. (2015). Mechanical Characteristics of Hollow Shear Connectors under Direct Shear Force, Steel and Composite Structures, 18(2), 467-480.
- Uenaka, K. & Tsunokake, H.(2014). Pure Bending Characteristics of Concrete Filled Elliptical Steel Tubular Beams, Proceeding of The 6th International Conference of Asian Concrete Federation, Asian Concrete Federation, 1079-1084, Seoul, South Korea, 2014.
- Uenaka, K.(2014). Experimental Study on Concrete Filled Elliptical/Oval Steel Tubular Stub Columns under Compression. Thin-Walled Structures, 78, 131-137.
- Uenaka, K.(2013). Concrete Filled Double Skin Circular Tubular Beams with Large Diameter-to-thickness Ratio under Shear. Thin-Walled Structures, 70, 33-38.
- Uenaka, K. & Higashiyama, H.(2013): Experimental Study on Half-pipe Shear Connectors under Direct Shear. Proceedings of the 2013 World Congress on Advances in Structural Engineering and Mechanics , Techno-Press, Jeju, South Korea, 2111-2119.
- Uenaka, K. & Kitoh, H.(2012). Concrete Filled Double Skin Circular Tubular Members subjected to Pure Bending and Centric Compressive Loading. Tubular Structures, 14, 81-87.
- Uenaka, K. & Kitoh, H.(2011). Mechanical Behavior of Concrete Filled Double Skin Tubular Circular Deep Beams. Thin-Walled Structures, 49(2), 256-263.
- Uenaka, K., Higashiyama ,H. & Ishikawa, T.(2010). Mechanical Behavior of Channel Shear Connector under Direct Shear. Proceedings of The 5th Civil Engineering Conference in the Asian Region and Australasian Structural Engineering Conference 2010 , Sydney, No. 117, Australia.
- Uenaka, K., Kitoh, H., & Sonoda, K. (2010). Concrete Filled Double Skin Circular Stub Columns under Compression. Thin-Walled Structures, 48(1), 19-24.
- Uenaka, K. & Kitoh, H.(2009). Bending-shear Behaviors of Deep Concrete Filled Double Steel Tubular Beams. Proceedings of 6th International Conference on Advances in Steel Structures, Hong Kong Institute of Steel Construction, 1, 498-505, Hong Kong, People's Republic of China.
- Uenaka, K., Kitoh, H. & Sonoda, K. (2008). Concrete Filled Double Skin Tubular Members subjected to Bending. Steel and Composite Structures, 8(4), 297-312.
- Uenaka, K., Kitoh, H., & Sonoda, K.(2008). Experimental Study on Concrete Filled Double Skin Tubular Members under Pure Bending. Proceedings of 4th International Conference on Advances in Structural Engineering and Mechanics , Techno-Press, Jeju, South Korea, 1915-1924.
- Uenaka, K., Kitoh, H., Sonoda, K. & Hayami, M.(2003). Experimental Study on Concrete Filled Double Tubular Steel Columns under Axial Loading, Advances in Structures, Balkema Press, 877-882.
- Sonoda, K., Kitoh, H. & Uenaka, K.(2000): Embossed Steel-Concrete Composite Member subjected to Bending and Shear, Composite Constructions in Steel and Concrete IV, American Society of Civil Engineers, Banff, Canada, 355-366.
- Kitoh, H., Uenaka, K., Uehira, K. & Sonoda, K.(1999): Bond Characteristics of the Embossed Steel Plates to Concrete, Proceedings of the fib Symposium, Fédération Intrnationale du Béton, Prague, Czech Republic, 2, 537-538.
- Uenaka, K., Kitoh, H., Uehira, K. & Sonoda, K.(1999): Shear Bond Characteristics of the Embossed Steel Plates with Headed Studs, Transactions of the Japan Concrete Institute, 20, 293-300.