Yoshikazu Araki

Yoshikazu Araki
Nagoya University | Meidai · Department of Environmental Engineering and Architecture

Doctor of Engineering

About

94
Publications
29,894
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,209
Citations
Additional affiliations
April 2018 - present
Nagoya University
Position
  • Professor (Full)
April 2004 - March 2018
Kyoto University
Position
  • Professor (Associate)
April 2000 - March 2004
Kyoto University
Position
  • Professor (Assistant)

Publications

Publications (94)
Article
Full-text available
Recently, single-crystal Cu-Al-Mn (CAM) superelastic alloy (SEA) bars have been developed to address the shortcomings of traditional Ni-Ti SEA bars, i.e., high cost, low workability, and lack of superelasticity at low temperatures. The CAM SEAs have a wide range of potential applications in biomedical, aerospace, mechanical, and civil industries. H...
Article
Full-text available
The objective of this paper is to examine the orientation dependence of plasticity and fracture in single-crystal superelastic Cu-Al-Mn shape memory alloy (SMA) bars. For this purpose, we prepared 14 single-crystal superelastic Cu-Al-Mn SMA bars of 15-mm diameter and 140-mm length. The crystal orientation was measured using electron backscatter dif...
Article
Cu-Al-Mn (CAM) superelastic alloys (SEAs) have been shown to improve the seismic performance of bridges and buildings by replacing the plastic hinge steel reinforcement. Despite research on mechanical performance at the material and structural scales, there is limited data on the degradation in the properties of CAM SEAs under harsh environmental c...
Article
Full-text available
This paper examines the feasibility of roll-threading superelastic Cu-Al-Mn shape memory allow (SMA) rods. The key idea behind this study was to perform roll-threading between quenching and aging, where cold workability of the material is relatively high. To obtain excellent superelasticity, single-crystal superelastic Cu-Al-Mn SMA rods were prepar...
Article
Full-text available
Full base shear seismic demand analyses with calculated examples for heavy stone masonry buildings are not present in the literature. To address this shortcoming, analyses and calculations are performed on nominally reinforced rubble stone masonry house and school designs, as typically built in Nepal. The seismic codes are literally applied for cou...
Article
Full-text available
Nearly 325 seismic and masonry codes from all over the world have been analyzed, of countries where stone masonry was, or still is, abundantly practiced. This paper compares and summarizes design specifications and construction requirements, with a specific focus on “nominally reinforced rubble stone masonry (NRM) with cement mortar and wooden diap...
Article
This research reports on the experimental verification of an enhanced energy conversion device utilizing a tuned inerter called a tuned inertial mass electromagnetic transducer (TIMET). The TIMET consists of a motor, a rotational mass, and a tuning spring. The motor and the rotational mass are connected to a ball screw and the tuning spring interfa...
Article
Full-text available
This paper analyzes the cost breakdown of earthquake resistant schools in Kaski District of Nepal, as built by Smart Shelter Foundation (SSF). Three types of designs are compared, which are rubble stone masonry with a wooden roof structure, and concrete block masonry with either a wooden roof or with a steel trussed roof. An in-depth cost analysis...
Article
Full-text available
The alkaline activator has a significant effect on the microstructure and mechanical properties of fly ash-based alkali activated products. This paper aims to identify the reaction products of fly ash (FA) activated with alkaline activators of different concentrations of Na2O and different SiO2/Na2O ratios. NaOH solution (NA), a mixture of NaOH and...
Article
Full-text available
A literature review was carried out with the aim to determine the current state-of-the-art with regards to non-engineered stone masonry in seismic areas. Specific search criteria and definitions were determined for school buildings with loadbearing walls of rubble stone masonry in cement mortar, nominally tied with horizontal reinforcements. A tota...
Article
Full-text available
In recent years, geopolymers have gained a wide attention as highly ecological-friendly building materials, having a capability to cut down 70% of CO2 emissions in comparison to the ordinary cement concrete. In this study, geopolymer mortars are proposed as repair materials for reinforced concrete structures, due to their superior acid resistance,...
Article
Full-text available
Self-centering earthquake resistant systems have attracted the attention of researchers because of their promising potential in controlling seismic residual drifts, and, therefore, reducing the associated repair costs. The use of Ni-Ti superelastic shape memory alloy (SMA) constitutes a considerable portion of this research. Cu-Al-Mn su-perelastic...
Article
Full-text available
This paper examines the feasibility of mechanical splicing using a steel coupler to connect headed ends of superelastic Cu-Al-Mn alloy (Camalloy) bars and steel reinforcing bars to be used in concrete structures. Although threading of Camalloy is as easy as that of steel, mechanical splicing using threaded ends requires machining of Camalloy bars i...
Chapter
Full-text available
In this research work, high-density concrete (μ = 4.71 g/cm³) using steel balls as aggregates and a normal concrete using recycled aggregates from the debris of the demolished concrete buildings of the earthquake-affected region have been evaluated for the radiation-shielding property for the radioactive contaminated soil in Fukushima. Two cylindri...
Article
Historic timber structures that are widely distributed in East Asia are suffering from the earthquakes. This research is aiming to develop a technique to enhance the seismic performance of historic timber buildings with Dou-Gon system. High strength steel bars and super-elastic alloy bars have been used instead of the conventional wood peg connecti...
Article
Full-text available
Producing a single crystal is expensive because of low mass productivity. Therefore, many metallic materials are being used in polycrystalline form, even though material properties are superior in a single crystal. Here we show that an extraordinarily large Cu-Al-Mn single crystal can be obtained by abnormal grain growth (AGG) induced by simple hea...
Article
This paper presents an energy-consistent approach for reducing the number of degrees-of-freedom (DOFs) in tall steel frames. In the present approach, the moment resistance of beams and columns in each story is represented by the moment resistance of a rotational spring and a beam-column element, respectively. The shear resistance provided by braces...
Article
This paper investigates the validity of the tuned inertial mass electromagnetic transducer (TIMET) applied to building structures subjected to seismic motions. The TIMET is a device inspired by two innovative structural control devices proposed recently, that is, tuned viscous mass damper and electromagnetic transducer. The TIMET consists of a spri...
Article
This paper presents a passive vertical quasi-zero-stiffness vibration isolator intended for relatively small objects. The present isolator has features of compactness, long stroke, and adjustability to various load capabilities. To realize these features, we use constant-force springs, which sustain constant load regardless of their elongation, and...
Article
Full-text available
Shape-memory alloys possess a number of unique characteristics, such as shape memory and superelasticity. Shape memory means the alloys return to their original condition when heated, whereas superelasticity allows large deformations with limited or no residual strain. When the alloys repeatedly undergo phase transformation, they have superior ener...
Article
Full-text available
This paper studies the response of Cu-Al-Mn superelastic alloy (SEA) bars to repeated tensile load at room temperature. The test specimens are three polycrystalline and one single crystal SEA bars of 11 mm diameter and 100 mm length. Strain-controlled tensile load is applied for 1,000 cycles with target strain amplitudes of 6–7%. In the test, varia...
Article
Shaking table tests are performed on a one-bay one-story steel frame with superelastic Cu–Al–Mn shape memory alloy (SMA) tension braces. The frame is subjected to a series of scaled ground motions recorded during the 1995 Kobe earthquake, Japan. The test results demonstrate that the SMA braces are effective to prevent residual deformations and pinc...
Article
SUMMARY This paper investigates the feasibility of tension braces using Cu–Al–Mn superelastic alloy bars as energy dissipating and self-centering elements for steel frames by performing 1/3 scale shaking table tests. The difficulty with conventional steel tension braces lies in pinching or significant deterioration of stiffness and strength under c...
Article
When high-rise buildings are subjected to intense earthquake ground motions, deformation concentrates into a restricted lower part of a building frame in the process of collapse even though it is designed in accordance with the strong-column-weak-beam concept. This paper examines the mechanisms behind the deformation concentration based on the moda...
Article
Full-text available
This paper studies the effectiveness of an externally activated self-repairing technique for concrete members with epoxy injection network and Cu-Al-Mn superelastic alloy (SEA) reinforcing bars (rebars). Compared to existing crack self-repairing and self-healing techniques, the epoxy injection network has the following strengths: (1) Different from...
Article
This paper proposes a turnbuckle brace with Cu-Al-Mn superelastic alloy for reducing residual deformation. Firstly, mechanical properties of Cu-Al-Mn superelastic alloy bar is obtained from coupon test. Secondly, mechanical behavior of screw joint with threaded superelastic alloy bar is examined from cyclic loading test. Then, design method of scre...
Article
Full-text available
The Truss Topology Design (TTD) problem deals with the selection of optimal configuration for pin-jointed trusses, in particular, optimization of the connectivity of the nodes by the members, in which volume and/or compliance are minimized. In general, it is known that such truss structures are statically determinate and not redundantly rigid, that...
Article
Full-text available
This article examines the feasibility of Cu-Al-Mn superelastic alloy bars as possible self-sensor components, taking electrical resistance measurement as a feedback. Superelastic alloy bars change their crystallographic structure with phase transformation, as well as electrical resistance during loading–unloading process at ambient temperature. Thi...
Article
This paper presents results from recent experiments performed on superelastic Cu-Al-Mn alloy bars (rods) with different diameters under various loading rates and temperatures. Previously, Araki et al. [2] tested the rate-dependent response of 8 mm bars up to 1 Hz loading rate. In this paper, loading rate (up to 15 Hz) and temperature (-40 to 50 deg...
Conference Paper
Full-text available
In order to solve the situation laying contaminated soils beside children on a daily basis, two types of shielding concrete pods and two levels of the contaminated soil with radioactive cesium were prepared. First concrete pod was made by special heavy concrete with the density of 4.57 g/cm3, which were developed by using special iron balls and dev...
Article
Full-text available
This paper reports extensive experimental study done to compare workability and bond strength of five different types of polymer-based bonding agents for reinforcing bars in pinning retrofit. In pinning retrofit, steel pins of 6 to 10 mm diameters are inserted into holes drilled diagonally from mortar joints. This technique is superior to other tec...
Article
Full-text available
In polycrystalline materials, grain growth occurs at elevated temperatures to reduce the total area of grain boundaries with high energy. The grain growth rate usually slows down with annealing time, making it hard to obtain grains larger than a millimeter in size. We report a crystal growth method that employs only a cyclic heat treatment to obtai...
Article
The aim of this article is to demonstrate the potential of using shape memory alloy (SMA) as a dowel in timber connection to provide a recenterable effect and higher energy dissipation capacity. Two dowel-type timber connections were fabricated for double shear tests under cyclic loadings. The results not only showed that the timber connection with...
Article
Full-text available
This study evaluated the radiation shielding performance of high density (4.57g/cm3) concrete containers against gamma rays radiated from soil volume source contaminated by radioactive cesium (134Cs and 137Cs), through experiments and analysis. From the results of the experiment, it was demonstrated that high density cylindrical concrete containers...
Article
This paper presents the results on shaking table tests of half-scale brick walls performed to investigate the effectiveness of newly developed Cu–Al–Mn superelastic alloy (SEA) bars in retrofitting of historical masonry constructions. Problems associated with conventional steel reinforcing bars lie in degradation of stiffness and strength, or pinch...
Article
We study the dynamic response of high-rise steel buckling-restrained braced frames (BRBFs). Three BRBFs designed using different design base shear are subjected to two types of artificial ground motions: One is the long-period ground motion with peak value of 250 cm/s around a dominant period of 3 sec in the velocity response spectrum, expected to...
Article
Full-text available
Experimental and numerical works are reported to assess the cyclic response of concrete beams reinforced with superelastic alloy (SEA) bars. The feasibility of newly developed Cu–Al–Mn SEA bars, characterized by large recovery strain, low material cost and high machinability, is examined as partial replacements for conventional steel bars, in order...
Article
The authors thank Dr. Hitoshi Kuwamura for his discussion. The authors' response to his discussion is as follows; 1) The mechanism of shear transmission between steel and timber is considered as combination of bearing and friction. 2) The formula to calculate the maximum shear strength has been revised. 3) Although the water content ratio varied in...
Article
Full-text available
We report the results of tensile cyclic loading tests conducted to examine the dependence of constitutive relations for superelastic Cu–Al–Mn alloy rods on loading rates. Recently, Cu–Al–Mn alloy rods with diameters up to 8 mm have been developed by the authors, and it has been demonstrated that these rods have excellent superelastic strains of mor...
Article
This paper reports the results of shaking table tests performed to assess the response of an object placed on a vibration isolator to intense ground motions whose peak accelerations are close to or over the gravity acceleration in both vertical and horizontal directions. The passive vertical and horizontal vibration isolator, developed by the autho...
Article
A shape and section optimization method is presented for free-form steel structures considering cost of connections. Two types of rigid connections are considered. One is a conventional full-strength connection, and the other is a partial-strength connection using for example fiber reinforced mortar. The inherently different costs of the two are ma...
Article
We study dynamic instability in high-rise steel moment resisting frames (SMRFs) subjected to synthetic long-period ground motions caused by hypothetical huge subduction earthquakes. Since long duration as well as long dominant periods is a characteristic of long-period ground motions, interstory drifts may enter the negative postyield stiffness ran...
Article
Full-text available
This paper investigates the applicability of newly developed Cu-Al-Mn shape memory alloy (SMA) bars to retrofitting of historical masonry constructions by performing quasi-static tests of half-scale brick walls subjected to cyclic out-of-plane flexure. Problems associated with conventional steel reinforcing bars lie in pinching, or degradation of s...
Article
Full-text available
This note examines the feasibility of an improved slotted bolted connection for timber moment frames. In the improved connection, steel tubes are inserted into drill holes in glulam and fixed to the glulam with resin injection. Aluminum splice plates with curved slots, or curved elongated holes, are fastened mechanically by using high-strength bolt...
Article
Firstly, a nonlinear optimization problem is formulated taking only representative dimensions of steel sections as independent design variables. The other dimensions are determined using proportions, prepared from a list of standard profiles, to the design variables. In the optimization, the members are divided into groups having identical sectiona...
Article
Although timber is a combustible material, the char layers created on the surface during fires prevent further burning of the inner sections. Taking advantage of this feature, steel-timber composite (a steel plate sandwiched with timber using high strength bolts) section members were developed, expecting steel alone to take the load under fires. In...
Article
Although timber structures are advantageous for their cost and fabrication, there is a difficulty in obtaining large members and assuring strength in joints. Composite section members with steel plates sandwiched with timber sections can overcome these disadvantages; however, an effective method is required for their connection. In this research, a...
Article
Full-text available
This paper focuses on finite element (FE) modeling of the out-of-plane response of retrofitted masonry walls subjected to quasistatic cyclic loading. Retrofitting involves inserting inclined stainless steel bars on the plane perpendicular to the wall face, already practiced in several historical masonry structures in Japan. The FE model for masonry...
Article
We present the results of the quasi-static cyclic tensile tests of Cu–Al–Mn shape memory alloy (SMA) bars of 4 and 8 mm diameters to examine their superelasticity and other mechanical properties closely related to seismic applications. The present Cu–Al–Mn SMA bars have achieved the recovery strains of over 8% and the fracture strains of over 17%....
Article
This paper reports the results of cyclic out-of-plane flexural experiments of brick wall specimens, reinforced by inserting stainless pins. Inserting stainless pins into unreinforced masonry walls is a technique suitable for the seismic retrofit of historic masonry constructions because of not only its lower cost and shorter construction period but...
Article
In this paper, we present a method for controlling the distribution of optimal member sections for a steel frame. The smoothing parameter is selected by using Bayesian Information Criterion, which is called ABIC. The checkerboard problem refers to the formulation of regions of alternating large and small elements ordered in a checkerboard-like fash...
Article
We present a vertical vibration isolator having a piecewise-constant restoring force, which belongs to a class of passive and nonlinear vibration isolators. In vertical vibration isolation, direct use of low-stiffness elements leads to unacceptably large deformations due to self-weight. To overcome the difficulty, we apply a combination of constant...
Article
We study the influence of the P-Δ effect on the dynamic response of 20 story moment-resisting steel frames under extreme earthquake ground motions. In this paper, we perform nonlinear time-history analyses of 3 frame models having different design base shear. The major findings include: (a) If the design base shear was close to the lower bound of e...