bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Analysis of Deployable Structure with Scissor-like-element in Architectural Design Class
Authors: Tagawa Hiroyuki , Sugiura Noritoshi , Kodama Shoko
Published: July 2015

A deployable structure with scissor-like-element is designed and constructed in architectural design class. In parallel, structural analyses are carried out using general finite element analysis program to evaluate the stability of intermediate models considered in the design process and determine the configuration of the final product. ods in deployable structure with scissor-like-element are modeled by beam element and hinge and pivotal joints are modeled by setting different nodes per rod located at these joints and imposing constraint equations on these nodal degrees-of-freedom. Stiffening effect by nylon ropes set up diagonally between hinge joints after the deployment is evaluated by the eigenvalue analysis. Beside structural analysis, architectural design process and the final product of deployable structure with scissor-like-element are described.
Structural design approach for slender buildings
Authors: Kawasaki Megumi , Shibata Yoshinobu , Fujinaga Naoki , Shinozaki Yozo
Published: July 2015

When designing a tall slender building, it is important to consider cases such as overturning, pulling out of column bases, and excessive deformation in the shorter elevation during earthquakes.

Where there is a single-span frame across the short (front) side of the structure, deformation readily concentrates in frame stories with low stiffness. If the frame yields in one story, plastic deformation is concentrated in that story, resulting in story collapse. However, there is a growing need to take measures to prevent such damage to building structural safety and usability when unpredictable events such as direct hit earthquakes occur. To meet this need, the authors propose a new frame system of superior performance and test its robustness.

This paper describes the vibration control structure of the new frame, as well as the new "through- wall-column" that forms part of the system.

The through-wall-column is an extremely stiff monolithic structure extending from the basement to the uppermost floor of the main building. It is located at the center of gravity of the building plan in order to avoid excessive concentration of shear force.

The application of this new structural system to a slender retail store building is also described. A structural plan taking full account of the design requirements was developed. Response displacement is controlled by oil dampers at the two narrow ends of the building. Small-diameter bracing dampers were adopted for reasons of design.

In planning this building, the new framing system with a through-wall-column was investigated from the initial setting up of various data to the details of its actual application.

The new system proved successful for the design of a slender building with highly qualified earthquake resistance, as well as structural flexibility.
Seismic Performance Evaluation on Historical Timber Frame Structures with Large Hanging Walls
Authors: Ohmura Saki , Yokobe Tatsuya , Shibuya Yoshihiro , Nambu Yasuhiro , Sugino Mina , Hayashi Yasuhiro
Published: July 2015

In this paper, static loading tests of timber frame structures with large hanging walls and beams (Sashigamoi) have been conducted in order to confirm the damage progress and the hysteresis characteristics until the restoring force loses. As the results of the static loading tests, the following results were obtained.

Specimens of which walls break before breakage of columns have high deformation performance.

Different specification of hanging walls and size of column section give different failure mechanism and bearing force of hanging walls. c) Ratio of shear force of columns given by the results of tests is different from the ratio based on the current code. d) Bearing force of hanging walls is varied by specification of frames such as section size of columns and thickness of crosspieces called Nuki. e) Rear columns are broken at the bending unit stress which is about the half of the flexural strength.
Corrosion evaluation of gusset plate connection removed from steel truss bridge
Authors: Nguyen Xuan Tung , Nogami Kuniei , Yoda Teruhiko , Kasano Hideyuki , Murakoshi Jun , Honda Hiroaki , Tashiro Daiki
Published: July 2015

Many steel bridges currently in use in Japan were built during the country's period of high economic growth. As a result, the number of bridges over 50 years old will increase drastically in the upcoming years. Due to heavy traffic and Japan's severe natural environment, deterioration and damage will increase rapidly. Concerning steel truss bridges, in particular, serious corrosion damage has been reported recently, especially on the diagonal members and the gusset plate connections. This study concerns the evaluation of a corrosion measurement method using laser equipment, which was used to determine the detailed corrosion state of connection P25u that was cut out from a five-span steel truss bridge. The actual corrosion state of the outer and inner surfaces of the gusset plates and the flange surfaces of diagonal members was investigated on the basis of the corrosion depth distribution. Based on the detailed results of corrosion measurement, the corrosion state and the corrosion characteristics of the connection were clarified.
Performance evaluation of the steel-concrete composite slab for the taxiway bridge that carries heavy aircraft
Authors: Kaneko Masahiro , Takei Yuzo , Yamaguhi Kohei , Hino Shinichi
Published: July 2015

At Narita international airport, a bridge is inevitable for the part of new taxiway due to constraints of existing structures. The bridge style taxiways are rare in the world and the design method is not clearly established at present. Therefore, after the design of this bridge adopting the method for vehicle bridges, verification of the results by FEM was done. Furthermore, punching shear loading tests using full scale specimens were carried out to confirm the punching shear strength that affects fatigue performance of the concrete slab and to inspect the mechanism of the process to failure.

Through these tests, it was identified that the deck slab has enough durability. Finally, after the completion of the construction of the bridge, loading tests by real aircraft were executed to identify the distribution of stresses inside the slab under normal use. The distribution of stresses matched assumed one well and it was confirmed the bridge is safe enough to support heavy aircraft.
Numerical Assessment of Seismic Performance of Super High-rise RC Buildings with Buckling Restrained Braces
Authors: Maida Yusuke , Maegawa Toshio , Demizu Toshihiko , Qu Zhe , Kishiki Shoichi , Sakata Hiroyasu , Wada Akira
Published: July 2015

In this paper, the passive control effect of BRBs in RC buildings subjected to earthquake ground motions is investigated by nonlinear time history analysis. In one model, the RC frame was braced by BRBs in each story (each model) and in the other one, each BRB spans over two stories (over model). The analysis results indicate that the over model exhibited almost the same passive control effect as compared to the 'each model', although the number of BRBs was significantly reduced and the RC beams in the braced span were abandoned.
Study on Damping Evaluation of Shell and Spatial Structures
Authors: Shingu Kiyoshi , Hiratsuka Kiyotoshi , Yukawa Masaki , Ishiyama Yusuke , Kondo Norio
Published: July 2015

Damping ratios are evaluated through impact vibration experiments and microtremor observation of two concrete spherical shell structures and two spatial structures. n the experiments, velocity detectors are used and velocities are measured at each measurement point. Further, damping characteristics of shell and spatial structures have been analysed using 55 data of damping of shell and spatial structures.
A Numerical Comparison Between Static Methods For Redundancy of Steel Truss Through Bridges
Authors: Hoang Khuyen Trong , Iwasaki Eiji
Published: July 2015

Structural redundancy analysis has become an important work since some recent bridge collapse accidents. In applications, a linear redundancy method is usually applied. This method is simple, but its accuracy is limited due to its assumptions of linear behavior. An alternative method, such as static nonlinear redundancy analysis, which is well known for higher precision, is not studying much. This paper investigates a nonlinear redundancy method, and compares result of linear redundancy analysis with result of nonlinear redundancy analysis that is applying in an explicit steel truss type bridge designed by Japan Specifications for Highway Bridges. The result by linear redundancy showed that the bridge collapsed after the sectional forces in some members reached its linear strength. On the other hand, in nonlinear analysis, redistribution of bending moments after yielding enlarged the member strength compared with the result of linear analysis. Hence, nonlinear redundancy analysis resulted in higher redundant level than a linear one did.
Design and Construction of Butterfly Web Bridge -Akutagawa Bridge-
Authors: Kaminaga Yuki , Ashizuka Kenichiro , Takahashi Akira , Yamamoto Taizo , Hashi Yutaka , Kawano Kensuke
Published: July 2015

Akutagawa Bridge is a continuous rigid frame bridge located between Takatsuki junction and Kobe junction on the New Meishin Expressway. This is where the new concrete precast "Butterfly Web Bridge" was applied, which uses butterfly shaped panels fabricated in a factory. Compared to a conventional concrete box-girder structure, this unique structure enables the reduction in dead load of the superstructure by approximately 10%. And, a decrease in construction costs is expected through the reduction of both prestressing steel weight and size of bridge substructure.
Fundamental Study on Effect of Fabrication Tolerance on Slip Strength of High Strength Bolted Friction Type Joint with Thick Plates
Authors: Takai Toshikazu , Peng Xue , Yamaguchi Takashi , Yamashina Kiyonori
Published: July 2015

This study focuses on fabrication tolerance of high strength bolted friction type joint. Many researches and studies have evaluated the effect of the tolerance of the joint to its strength. However, this paper especially focuses on long joints with extremely thick plates (75 mm) that contain many bolts (12 bolts) in a line. Past experimental and FEM analytical results have been investigated, which provides statistical characteristics of fabrication variations related to strength of joint.

The characteristic value obtained from the investigation shows that the variation of the thickness of coating (inorganic zing-rich paint) hardly affects the slip strength of the joint. Furthermore, the influence of the variations is evaluated based on the FEM analysis considering the statistical values obtained from the investigation. The results indicate some variations strongly affect to the slip strength. This paper deals with the joints which have a high slip/yield strength ratio and compares the results among the long/not-long joins. The results of the FEM analysis show that the variations of Young's modulus and yield point of the plates, friction coefficient of connected surfaces and pre- load of the bolts significantly affect the slip strength of long joints.
Composite Stiffness of Asphalt and Deck and Its Influence on RD Joint
Authors: Li Ming , Suzuki Yasuo , Sugiura Kunitomo , Aoki Yasumoto , Adachi Yukio , Hashimoto Kunitaro
Published: July 2015

Numerous fatigue cracks were observed recently in many long-time served orthotropic deck bridges. Especially the cracks initiating from rib-to-deck (RD) joint may produce asphalt surfacing damage and hence cause impact on traffic safety. For fatigue evaluation of RD joints, in most current design specifications, the asphalt surfacing is just treated as a layer dispersing wheel loads and the effect of composite stiffness of asphalt surfacing and deck plate is neglected. In this study, Full size experiment for 2 spans orthotropic bridge deck with asphalt surfacing were carried out to investigate the stress distribution around RD joints and a special indoor asphalt heating and cooling system was employed to study the real stress distribution around RD joint with considering asphalt temperature variation. The experiment results show that the most critical transversal load cases for fatigue damage of RD joint are wheel load ride on the RD joint and located around the adjacent RD joint. Moreover the transversal stresses around RD joint are significantly sensitive to the asphalt temperature and the most sensitive temperature range is 5 degree Celsius to 35 degree Celsius.
Structural vibration characteristics of a pedestrian bridge by the 3D acceleration sensing of smart sensors and detailed 3D-FEM model
Authors: Kadota Takanori , Miyamori Yasunori , Watasaki Ryosuke , Mikami Shuichi , Saito Takehiko
Published: July 2015

In this study, we conducted fundamental study of structural health monitoring (SHM) by using 3- dimensional acceleration measurement and high resolution FE model analysis of a simple pedestrian overpass having an actual damage. Vibration measurement is performed on the pedestrian bridge by using Imote2 smart sensors. Plural vibration modes are identified from damped free vibration experiments. To reproduce the measured vibration characteristics with satisfactory accuracy for SHM in the analytical model, it is necessary to appropriately model the boundary conditions and secondary members. In this study, modelling of connecting part of main girder and stairs is examined in several patterns. Then, appropriate method of detailed FE modelling is discussed by comparing natural vibration characteristics from eigenvalue analysis.
Preliminary Experiments of a Structural Health Monitoring Method with an Accurately Controlled Small Vibrator and Wireless Sensor Networks
Authors: Otani Takahiro , Okumura Takefumi , Tsukahara Mika , Ishii Katsuya , Saeki Masayuki
Published: July 2015

This paper shows a structural health monitoring method based on artificially induced vibration response measurements. The method utilizes an accurately controlled small vibrator and multiple wireless sensors, and is capable of precisely measuring frequency response functions in a specified frequency band. The paper shows a design of the instruments and a structure estimation procedure which utilizes the above mechanical system. The procedure is based on the structural analysis of the linear N-degree-of-freedom system and formalizes the task as a maximum likelihood estimation problem. The effectiveness of the method is verified by a numerical simulation with a simple model, and its usability and limits are discussed.
Mechanical Properties and Evaluation of Concrete Beams Made of a Large Amount of Fine Fly Ash
Authors: Wang Junhua
Published: July 2015

Nine reinforced concrete beams were fabricated and tested under monotonic shear and bending to investigate effects of the fine fly ash content on ultimate shear strength and deformation capacity of concrete beams. Taking the fine fly ash content, the shear span ratio, and the section size of beams as primary experimental variables, all test beams were prismatic beams and made of concrete with a water-to-cement ratio as low as 65%. Test results have indicated that increasing the fly ash content can enhance both ultimate shear strength and deformation capacity. The larger the quantity of fine fly ash, the higher the shear strength and the rotation angle at the peak shear. The use of 455 kg/m3 fly ash per unit volume in a concrete beam, which had no transverse hoops and had shear span ratio of 1.0, could enhance the ultimate rotation angle of the beam up to 0.02 radian.
Corrosion deterioration characteristics of Sn-bearing steel and its applicability on steel bridges
Authors: Okuno Takafumi , Hirohata Mikihito , Kamimura Takayuki , Itoh Yoshito
Published: July 2015

The steel with a small amount of tin (Sn), that is, Sn-bearing steel was newly developed by noting the effect of adding such kind of trace alloy element for improving the corrosion resistance of steel. In order to investigate the corrosion deterioration characteristics around paint coating defect of the Sn-bearing steel, accelerated exposure test was performed. After the test, the appearance and surface shape of paint coated Sn-bearing steel were examined for evaluating the degree of deterioration. The corrosion deterioration was evaluated by focusing on the blister of paint coating around the initial defect scribed in X shape (namely, cross-scribe defect). The blister areas from the cross scribe paint defect of the Sn-bearing steel was respectively 95 % in A-type coating and 43 % in C-type coating of those of the SM490 steel at 2200 cycles. For C-type coating, the use of Sn- bearing steel to bridges has the possibility to prolong the life span of paint coating by around l5 %.
Repairing Method for Steel Member with Cross Section Loss by CFRP Bonding
Authors: Hidekuma Yuya , Miyashita Takeshi , Okuyama Yusuke , Ishikawa Toshiyuki , Kobayashi Akira
Published: July 2015

As a repairing method for corroded steel members, a method to bond the carbon fiber sheets with resin to the steel member had been developed. Commonly, the carbon fiber sheet having the tensile stiffness equal to or greater than that of the cross-section loss is bonded to the steel member.

However, in the case of such repairing method, it have been reported that the reinforcing effect may be not sufficient. In this study, a new repairing method was proposed for the steel member having cross-section defects. In new design method, the carbon fiber sheets having the tensile stiffness of the inverse number times of the residual ratio of the defect parts of steel are bonded. In order to confirm the validity of the proposed method, the tensile test and the numerical analysis were carried out. The result showed that the tensile stiffness at the cross-section defect part is recovered to equal to or greater than the original tensile stiffness by bonding the carbon fiber sheet.
Static and seismic analysis of multi-span cable-stayed bridges with steel and CFT towers
Authors: Okamoto Yutaka , Nakamura Shunichi
Published: July 2015

Multi-span cable-stayed bridge is a new and attractive structure. The tower plays an important role to improve the seismic resistance. Two types of towers were studied in this paper: the steel tower and the concrete filled steel tower (CFT tower) which consists of a steel double box section filled with concrete. First, static analysis was conducted to clarify how different pattern of live load distributions affect the multi-span cable-stayed bridge. The live loads applied on alternate spans give the critical bending moments and displacements. Second, seismic analysis was conducted with two different towers due to the ultra-strong earthquake. Three longitudinal support conditions of the girder at the tower positions are considered: movable supports, linear spring supports and bi-linear spring supports. Response and bending moments of the towers are lowest with bi-linear support because seismic energy is dissipated.
NEW CONCEPTUAL DESIGN FOR A TEMPORARY BRIDGE WITH A TRANSFORMABLE STRUCTURAL FORM
Authors: Kishimoto Takahiro
Published: July 2015

When bridges cannot be crossed during natural disasters, temporary bridges are constructed as part of emergency recovery efforts to restore road networks, thereby enabling transportation of refuge and relief supplies. Temporary bridges, however, generally have some disadvantages, including lengthy construction times. Their sizes are restricted by the transporting truck's capacity for transformability. In addition, the span length of these bridges is not easily transformable on site. Thus, this paper proposes a new conceptual design for temporary bridges to overcome these problems. The conceptual design consists of a design concept and a structural design. The design concept consists of (1) a flexible structural form, (2) enhanced transportability, and (3) more efficient construction. The structural design consists of (1) an extendable span system, (2) consolidation of the form system, and (3) simplified and low-on-labor construction.
Optimal Design of Outrigger Systems for Super Tall Buildings
Authors: Zhao Xin , Qin Lang , Dong Yaomin , Jiang Xiang
Published: July 2015

Applied widely to increase the lateral stiffness of supper tall buildings, outriggers can effectively reduce vibration period as well as the structural lateral deflection under wind loads and earthquake actions. Based on the feature of mega frame-core wall structures, this paper discussed the optimal design of outrigger trusses. The location and number of outriggers are optimized by adopting sensitivity vectors algorithm (SVA) method proposed by the authors. Using the principle of virtual work and Rayleigh method, the relationships between the structural member sectional dimensions and the design criteria, such as the story drift and vibration period, are established. Then a Matlab- based computer programe is developed on the basis of SQP approach to minimize the volume of outrigger truss members under multiple constraints. A 729-meter real super tall building project is employed to illustrate the applicability and effectiveness of the proposed optimal design method.
Design and Construction of Bamboo Spatial Structure Using Bended Bamboo Arch and Handmade Joint
Authors: Toki Hirokazu , Nagai Takuo
Published: July 2015

In this article, design and construction process of a building made of bamboo is reported. The design and construction were required to be conducted so that it can be made by manual labor of students due to the limited budget and materials right after the disaster of the East Japan Great Earthquake on 2011. To satisfy those requirements, bamboo which is supplied easily at near the site, was adopted as structural material, and handmade joint with enough strength was developed. We verified the structural behavior and performance of this building by experiments and numerical analysis, and obtained the building permit under the Japan building standard law as 4 years- temporary building made of bamboo structure.
The Long Span Structure Using a Skelsion Structure (Haneda Airport International Terminal Station)
Authors: Ootake Katsuhrio , Sato Yoshihisa , Hosozawa Osamu
Published: July 2015

The skelsion with tension strings (hereafter referred to Skelsion) structure is the combination system of Beam String Structure (hereafter referred to BSS) with brace. This structure system is tension structure. The structure system is materialized by initial tension load. This paper is an introduction of the structure system and construction technique for initial tension load.

The skelsion is a structure system made by slender element using BSS and the tie rods. BSS have been used to resist vertical load. The tie rods were installed in three dimensions to connect each BSS to prevent blowing up by wind load and to resist horizontal seismic load. The tie rods function combination for at both span and girder directions. This structure system was applied for roof of Haneda Airport International Terminal Station (Tokyo Monorail).

The length of span is 31.4m, and girder direction is 2.7 m X 12 units. This structure system is rigid frame structure by H-beams, BSS with combination posts and cables, and the tie rods installed in three dimensions. Two cables for BSS were employed in parallel on each beam. The vertical braces were used for girder direction at the bottom part to secure rigidity. The solid ball joint is installed at the crossing point of five tie rods. The horizontal braces were employed at roof surface between beams and sub-beams to secure rigidity.

These slender elements are showed above platform area and combined with high transparency glass exterior wall. The large span structure with light impression is realized.
The Fiber Concrete Prestressed Ring of the Memorial
Authors: Weill Jean-Marc
Published: July 2015

Tntroduction

Fig.l: The elliptic ring memorial (Source Eiffage+Jerome Pouille Photographer)

Fitting into the site, geometry and geology aspects.

The Ultra High Performance Fiber -Reinforced Concrete Material 4-Structural Analysis

5-Building the ring-ellipse
Collision Analysis of Submerged Floating Tunnel by Underwater Navigating Vessel
Authors: Hong Kwan-Young , Lee Gye-Hee
Published: July 2015

To recognize the collision behavior between a submerged floating tunnel (SFT) and an underwater navigating vessel (UNV), both structure were modelled and analyzed in this paper. The collision span of SFT is a tubular section that was modelled using concrete with steel lining. The other parts of the SFT were modelled elastic beam elements. Mooring lines were modelled as cable elements with tension. The UNV was assumed to be a 1,800 displacement tonnage (DT) submarine, and its total mass at collision was obtained through hydrodynamic added mass. The buoyancy force on the SFT was included in its initial condition using a dynamic relaxation method. The buoyancy ratio (B/W) and the collision speed were considered as the collision conditions. As results, energy dissipation was concentrated on the SFT and that on the UNV was minor. In addition, the collision behavior was greatly depended on B/W and the tension of the mooring lines. In particular, the collision forces showed different tendencies compared to vessel collision forces of the current design code.
Elastic-plastic Behavior of Steel and Concrete Composite Columns Using Cruciform Steel
Authors: Kuratomi Yo , Sakai Junichi , Tanaka Teruhisa
Published: July 2015

The authors have designed to develop two types of steel and concrete (hereinafter referred to as SC, and the other OSC) composite members not used reinforced bars. The details of SC cross section are composed of steel and concrete composite section encased cruciform steel and covered by thin steel tube. On the other hand, OSC sections are composed of only cruciform steel and concrete, and the cross section shape forms an Octagon. In order to study the elastic-plastic behavior of steel and concrete composite columns under earthquake loading, 14 specimens were tested. From the experimental results, SC columns and OSC columns showed good seismic performance up to large deformation. By comparing the elastic-plastic behavior of SC columns with that of OSC columns, when used high strength concrete, SC columns have advantage due to strong confinement effect to the column confined by encased cruciform steel and steel tube.
SEISMIC EFFECT OF MEMBERS FRACTURE ON TRUSS TOWER
Authors: Matsui Ryota , Takeuchi Toru , Horiuchi Kentaro , Imamura Akira , Ogawa Toshiyuki
Published: July 2015

Although truss towers used for telecommunication, electric power transportation, supporting structures for stacks in power plants have been designed against wind loads, a higher level of safety is recently required because of the increase of anticipated large seismic inputs. The ultimate strength of these structures is governed by buckling of tubular members which easily leads to the member fracture. This paper proposes the post-fracture analysis methods for truss structures composed with tubular members with high diameter-to-thickness ratios, and a study on the collapse mechanism of such truss towers after buckling and fracture of members is investigated using incremental dynamic analysis (IDA) analysis. Truss towers without stack members exhibited collapse after buckling of main columns or fracture of diagonal members. The collapse occurred approximately 1.5 times elastic limit.
Structural Retrofitting of Buildings: Turnbuckle Exterior Post Tensioning
Authors: Toral Kenneth , Lejano Bernardo
Published: July 2015

Nowadays the problem of aging and deterioration of reinforced concrete buildings are eminent and due to excessive loading, the flexural performance and serviceability of structures are affected. The turnbuckle exterior post tensioning (T-EPT) is proposed as a retrofitting method wherein it was proven experimentally that it can be able to improve the serviceability and load carrying capacity of beams. A computer modeling method was developed to simulate the application of the T-EPT to full scale beam sections to determine ist effectiveness with different cases. The behavior of the beams as observed from the experimental phase was attributed to the computer model to accurately simulate ist behavior. Different T-EPT configurations were modeled and from there, the most efficient design that can be applied to structures was determined. Overall the T-EPT was effective in improving the serviceability and load carrying capacity of reinforced concrete beams.
Dynamic Responses of High-Rise Base-Isolated Building during the 2011 Great East Japan Earthquake
Authors: Matsuda Kazuhiro , Kasai Kazuhiko
Published: July 2015

Seismic responses of a high-rise base-isolated building in Tokyo Institute of Technology were recorded during the 2011 Tohoku-oki earthquake. The purpose of this paper is to point out various important findings on the building responses from the recorded data, as well as to create the data base for fostering immature research areas on high-rise base-isolated buildings and monitoring. This paper explains a variety of numerical techniques such as transfer function curve-fitting procedure for system identification, comparison with conventional structure by modal analysis, damper hysteresis, axial force variation of rubber bearing, and dynamic characteristic variation due to input amplitude. Reliability of recorded results is confirmed by various methods, and applicabilities of the techniques for the high-rise isolated building are discussed.
Corrosion Damage Assessment for Simply Supported Steel-Concrete Composite Bridges
Authors: Lin Weiwei , Yoda Teruhiko , Lam Heang
Published: July 2015

In Japan, there are more than 50,000 steel railway bridges, where more than half of them have been used over 60 years and some bridges are aged over 100 years. With aging, corrosion becomes one of the major causes of steel deterioration, and its damages seriously affect the durability of steel bridges. On this background, a collapsed steel-concrete composite bridge due to severe corrosion was investigated by using finite element method. Measured corrosion data after the bridge collapse was considered in the numerical simulation, and the failure process was simulated. In addition, parametric analysis was conducted to confirm the contributions of different section loss (due to corrosion) locations to the bridge collapse. The present results in this paper can be used for maintenance and management of existing steel-concrete composite bridges and also can be used for designing new steel-concrete composite bridge structures with higher redundancy.
Vibration measurement with routing-free multihop wireless sensor networks and its application to a long-span bridge
Authors: Nagayama Tomonori , Suzuki Makoto , Narazaki Yasutaka , Morikawa Hiroyuki , Fujino Yozo
Published: July 2015

The use of wireless sensor networks for long span bridge monitoring has been expected to remove large portions of sensor installation cost and time. However, the large size of such structures poses difficulties. The communication distances are oftentimes shorter than the bridge scale. Elaborated plans on RF transmission and installation locations are often required. The authors proposed the use of efficient flooding scheme exploiting constructive interference phenomena. This approach does not require routing. Even when the RF communication environment is not stable, the path information does not need to be updated. As a result, the multihop communication becomes simple and robust, allowing to realize easy and inexpensive sensor networks covering large structures. This communication method is first introduced and then applied to a long-span suspension bridge vibration measurement. The identified dynamic characteristics of the target bridge are discussed.
Development of Tuned Dual-Mass Electric Power Generator for Energy Harvesting of Bridge Vibration
Authors: Takeya Kouichi , Sasaki Eiichi
Published: July 2015

A high quality bridge vibration energy harvester has been proposed in this paper using a tuned dual- mass damper system, named hereafter Tuned Mass Generator (TMG). To harvest and make use of the unused reserve of energy the aforementioned damper system absorbs, a new type of linear electromagnetic transducer has also been applied. The benefits of using dual-mass systems over single-mass systems for power generation have been clarified according to the theory of vibrations. TMG parameters have been determined considering multi-domain parameters, and TMG has been tuned using a newly proposed parameter design method. Experimental results obtained from a trial bridge have verified that for effective energy harvesting, it is essential that TMG has robustness against uncertainties in bridge vibrations, and the proposed TMG has demonstrated this feature.
Non-Linear Ultrasonic Test for Fiber-Reinforced Concrete using 3rd Harmonic Generation
Authors: Ongpeng Jason Maximino C. , Oreta Andres Winston C. , Hirose Sohichi
Published: July 2015

This paper presents non-linear ultrasonic behavior observed in ultrasonic transmission test for fiber- reinforced concrete cubes 150mm x 150mm x 150mm with three water-cement ratios 40%, 50% and 60%. The fibers used were short steel fibers having 1% volumetric ratio. Modes of failure were documented using pictures to relate the behavior of the 3rd harmonic amplitude as load patterns were varied. The normalized 3rd harmonic generation were generated thru Fast Fourier Transform FFT frequency spectra and normalizing it at fundamental frequency of 100kHz. The difference (3rd harmonic dB difference) from each varying step load for the 3rd harmonic amplitude and baseline of zero load's 3rd harmonic amplitude were analyzed. Categorization of modes of failure was done to generalize the behavior of 3rd harmonic dB difference according to the step load pattern. The satisfactory mode of failure produced similar pattern with respect to the step load variation. The 3rd harmonic dB difference increases as load increases, and decreases when the load decreases.
Trigger Analysis for Wireless Bridge Earthquake Monitoring System
Authors: Minesawa George V. , Sasaki Eiichi , Suganuma Hisada
Published: July 2015

Bridge Structural Health Monitoring (SHM) system could provide the assessment of the bridge structure condition immediately after the occurrence of a major seismic event, potentially enhancing safety and reducing the time needed for evaluating the bridge state before bridge is being returned to service.

The bridge wireless SHM sensor node operates on batteries and records data intermittently, when triggered. The sensors located on the bridge records both seismic events and various traffic induced vibrations. An independent triggering algorithm of each sensor node using the acceleration data recorded on the bridge has been adopted. Several trigger algorithms are being compared for enhancing detection of seismic events in the presence of the traffic and wind induced vibration. The preliminary analysis of the data at the bridge sensor setup location is being used for the validation of the proposed triggering algorithm. An in-memory event classification algorithm is being used to determine seismic events triggers and traffic induced triggers. Trigger detection with simulated earthquake records data was conducted to evaluate the effectiveness of trigger detection algorithm.
Corrosion Detection for Steel Wires in Bridge Cables Using Magnetic Method
Authors: Zhang Qiwei , Xin Rongya , Ji Yunfeng
Published: July 2015

Steel Cables are major load-carrying components in cable-supported bridges. The magnetic flux testing method is believed to be feasible to detect steel wire corrosion in bridge cables by evaluating loss of metallic cross section area (LMA). The magnetic properties of rust are vastly different from those of steel, thus making a decrease in both main-flux and return-flux which can be identified by LMA measuring. Variations in the length, width and depth of the corrosion zone will also cause disturbance in the output of the LMA-measuring sensors. The main object of this fundamental research is to clarify the influence of corrosion size on LMA signals during the steel wire magnetic detection. Finite element method (FEM) is used to simulate the magnetic flux testing for steel wires with LMA defects. Variable parameters considered in the FE model include sizes and locations of LMA defects, air gap between the cable and the magnets, and diameter of the cable under test. Model experiments are conducted in our lab for comparison with the FEM simulation. A defect- length factor is suggested to describe the influence of the defect length on the LMA signal and a calibrating method is proposed to eliminate the effect of flaw sizes in LMA quantitative evaluation.
Reinforcement Mechanism of a Gravity-type Breakwater with Steel Walls
Authors: Moriyasu Shunsuke , Kikuchi Yoshiaki , Kawabe Shohei , Tanaka Ryuta , Oikawa Shin
Published: July 2015

"Persistence" is needed for facilities that lied on the coast, since the coastal areas of Tohoku have been extensive damaged by the tsunami caused by the Great East Japan Earthquake (Mw9.0). For existing gravity-type breakwaters, the authors propose a new reinforcement method in which a steel pipe pile wall is placed behind a caisson and the space between the caisson and wall is filled with rubble. By the laterally loading experiment, the proposed method shows the persistent feature that the resistance increases with increasing caisson displacement. Next, analyzing FEM simulation for the experiment, it is discussed how the force of the tsunami is transferred from a caisson to a seabed layer by steel pipe pile wall and filling. This is unique point because the proposed method can utilize the soil resistance of the seabed layer, and this is the reason that the proposed method can show persistence.
Development of Large Tuned Mass Damper with Stroke Control System for Seismic Upgrading of Existing High-rise Building
Authors: Yaguchi Tomoki , Kurino Haruhiko , Kano Naoki , Nakai Takeshi , Fukuda Ryusuke
Published: July 2015

This paper describes a large TMD developed as an effective seismic control device for an existing high-rise building. There were two challenges to be overcome to realize the system. One is how to support a huge mass move in any direction, and the second is how to control mass displacement that reaches about 2 meters. As a solution to the former problem, a simple pendulum mechanism is adopted. To solve latter problem, we developed a high-performance oil damper with unique failsafe functions. This paper first examines the requirements of the TMD using a simple model and clarifies the constitution of the actual system. After the control effect through earthquake response analyses is discussed, the results of performance tests conducted on a full-scale TMD system for retrofitting an existing high-rise building are described.
Design Procedure for Stiffening Panels of Slitted Steel Shear Wall
Authors: Ito Mai , Hayashi Kazuhiro , Nakashima Masayoshi
Published: July 2015

Slitted steel shear wall stiffened by plywood panels is suggested as a new type of stud-type damper for the seismic retrofitting of buildings with many windows. Using experimental observations, finite element method analysis, and equations of plate lateral buckling, design procedures were proposed for estimating the required thickness of wood panels used to stiffen the slitted steel shear wall. Setting the ratio of modified buckling strength, which was obtained by assuming the effect of stiffening as an increase in bending stiffness relative to the yield strength, the design equations for the required stiffening panel thickness were derived. The design equations allowed the estimations of the effect of number of bolts and dimensions, and produced reasonable results in comparison with the experiments and numerical analyses.
CFD Wind-resistant Design of Tall Building in Actual Urban Area Using Unstructured-grid LES
Authors: Yoshikawa Masaru , Tamura Tetsuro
Published: July 2015

Recent development of high-performance computers and numerical techniques on wind engineering has enabled us to simulate the complicated flow such as the wind around buildings. Computational Fluid Dynamics (CFD) is expected to be adopted as an applicable technique for evaluating wind load for wind-resistant design of buildings. For numerical prediction of fluctuating wind pressures on buildings, Large Eddy Simulation (LES) is effective to simulate unsteady flows around buildings. The authors performed LES for investigating the wind characteristics in a real urban district. The complicated flow field in an urban area is reproduced by LES using unstructured grid system. In

this paper, the computed pressures on a tall building are compared with experiments and the applicability of unstructured LES for wind-resistant design of buildings is examined.
Aeroelastic Control of Long Span Suspension Bridges during Erection
Authors: Bakis Konstantinos N. , Massaro Matteo , Williams Martin S. , Limebeer D. J.
Published: July 2015

The 3D structural and aerodynamic modelling of a long span suspension bridge is considered and emphasis is placed on the simulation of the aeroelastic properties during the deck erection process. We then employ a leading-and trailing edge flap configuration on a finite deck length around the mid-point of the main span and investigate ist effectiveness in raising the critical flutter and divergence speed. In order to account for modelling errors and uncertainties in the controller design process we invoke elements from robust control theory and a nonlinear optimization algorithm is proposed to achieve the performance objectives.
A Proposal of Cable-stayed Bridge Composed of Steel Girder and Concrete Girder for Progress in Aerodynamic Stability and Seismic Performance
Authors: Ninomiya Yuuji , Okamoto Mitsuharu , Tanaka Gou
Published: July 2015

The Ikina Bridge spans the strait between the islands of Ikina and Sashima in Ehime prefecture, Japan. Since the particular geographic conditions at the bridge site of the Ikina Bridge pose problem of bad ratio of main span and side spans, a composite cable-stayed bridge structure combining a light-weight steel girder and heavy-weight concrete girders is adopted to ensure the correct sectional forces balance. While a steel girder and concrete girders are joined near the main towers in conventional composite cable-stayed bridges, in the Ikina Bridge, the concrete girder ranges are expanded to positions approximately 1/4 of the main span length from each of the main towers, where they are joined to the steel girder in order to improve not only the workability and economic efficiency of the over-the-sea bridge, but also the wind resistance. A main girder design that achieves excellent economic efficiency by taking simple and rational wind resistance countermeasures was selected after verifying the wind resistance through wind-tunnel tests. In addition, H-shaped concrete main towers are adopted due to their excellent wind resistance and durability, as well as their conformance to the narrow road width condition. Sufficient antiseismic performance of the concrete main towers is ensured by reducing the self-weight by adopting a hollow cross-section and reducing sectional forces by allowing minor plastic deformations in the connecting beams at the top of the H-shaped main towers. Note that this bridge is the first composite cable-stayed bridge in Japan in which stay-cables are anchored diagonally at both steel and concrete girders along the main span.
Controlling Wind Response with Innovative Damper Technology
Authors: Burton Melissa , Cammelli Stefano , Angus Rob , Montgomery Michael
Published: July 2015

A time of architectural aspirations to build super-tall towers has never been more pronounced than it is today. At present there are approximately 80 super-tall towers with heights in excess of 300 m worldwide, this number has more than tripled over the last decade [1]. As design teams seek to push the heights of buildings even taller, engineers and architects are required to be innovative in material use, aerodynamic form finding and in the choice of methods to reducing excessive dynamic response. Three tall buildings have recently been studied in BMT Fluid Mechanics' large boundary layer wind tunnel; one in Tianjin - China (550 m), one in New York City - USA (400 m), and one in Bangkok - Thailand (200m) and a research and development study of a tower in Toronto

- Canada (200 m). Wind tunnel testing highlighted the potential for the highest occupied floors of the towers to experience levels of wind-induced motion that exceeded standard industry occupant comfort criteria. Various methods of controlling the tower motions were considered (aerodynamic optimization, tuned mass dampers (TMDs), and viscoelastic coupling dampers (VCDs)). Each of these solutions has its own merits and faults, the decision for each is typically formulated around space requirements, financial constraints and level of damping required. This technical paper will discuss how innovation was required in both the analysis methods and the damper designs in order to enable the architectural vision for each of these three towers to be achieved and for the research and development study tower.
Structural Protection of Elegant Structures from Wind and Seismic Events
Authors: Fobo Wolfgang , Huber Peter
Published: July 2015

At the hand of 3 slender structures, the authors propose required characteristics of an optimum protection system with Tuned Mass Dampers (TMD) from wind and earthquake and highlight their benefits. Such protection systems consisting on TMDs do not only ensure structural safety, but might also be of commercial relevance, as they may reduce the total construction costs.
Ultra High-rise Building with High Seismic Performance and Dampers Concentrated on Specific Stories
Authors: Kimura Seiya , Koitabashi Yuichi , Ishii Masato , Fuji Shinichi
Published: July 2015

In recent years, frequently the plan and cross-sections of ultra high-rise buildings in Japan have become more complex associated with diversification of use. Also, frequently the lower levels include an atrium space or similar in order to function as public space.

The Yomiuri Shimbun Tokyo Headquarters Building has been designed as a comfortable space with extremely high seismic performance, with a rational structural scheme for a building as described above.
Shaking Table Test on Seismic Performance of Ceiling without Braces and Artificial Spacing to Surrounding Object
Authors: Tahara Kenichi , Sasaki Yasuhito , Sato Yukihiro , Sasaki Satoshi , Motoyui Shojiro
Published: July 2015

A ceiling without artificial spacing to surrounding object ("non-clearance ceiling") is a kind of suspended ceiling, which uses walls, beams or other surrounding objects to support the seismic force of the ceiling. Some previous studies reported that larger gaps between the ceiling and the surrounding objects cause a larger collision force for the ceiling.

In this study, a shaking table test was carried out to investigate the seismic performance of the non- clearance ceiling. The main parameters of the tests are the type of the surrounding objects (beam or light gauge steel wall), axis of the ceilings, gap width and the scale of the input earthquake waves.
Improving Access to, Quality, and the Effectiveness of Digital Tutoring in K–12 Education
Authors: Burch Patricia , Good Annalee , Heinrich Carolyn
Published: July 2015

There is considerable variation in how providers of digital education describe what they do, their services, how students access services, and what is delivered, complicating efforts to accurately assess its impact. We examine program characteristics of digital tutoring providers using rich, longitudinal observational and interview data and then analyze student attendance patterns and effects of digital tutoring on low-income students’ reading and mathematics achievement. We find significant associations between formats, curriculum drivers, tutor locations, and other characteristics of digital providers and their effectiveness in increasing student achievement, as well as differential access by student characteristics, that warrant further investigation as digital providers’ roles in K–12 instruction continue to expand.