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CONTENTS
Volume 62, Number 4, May25 2017
 

Abstract
In the present study, the advanced procedure has been proposed to estimate higher accuracy of embedment of pipes that are installed on soft clay seabed. Numerical simulation by OrcaFlex simulation code was performed to investigate dynamic seabed embedment, and two steps, i.e., static and dynamic analysis, were adopted. In total, four empirical curves were developed to estimate the seabed embedment including dynamic phenomena, i.e., behaviour of vessel, environmental condition, and behaviour of nonlinear soil. The obtained results were compared with existing methods (named general method) such as design code or guideline to examine the difference of seabed embedment for existing and advance methods. Once this process was carried out for each case, a diagram for estimating seabed embedment was established. The applicability of the proposed method was verified through applied examples with field survey data. This method will be very useful in predicting seabed embedment on soft clay, and the structural behaviours of installed subsea pipelines can be changed by the obtained seabed embedment in association with on-bottom stability, free span, and many others.

Key Words
seabed embedment; soft clay; dynamic installation; dynamic environment; pipe-soil interaction

Address
S.Y. Yu, D.K. Kim: Ocean and Ship Technology, Deepwater Technology Mission Oriented Research, Department of Civil and Environmental Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia

H.S. Choi: Graduate School of Engineering Mastership, Pohang University of Science and Technology, 37673 Pohang, Republic of Korea

K.S. Park, D.K. Kim: Steel Structure Research Group, POSCO Global R&D Center, 21985 Incheon, Republic of Korea

Y.T. Kim: Environmental and Plant Engineering Research Team, Daewoo Institute of Construction Technology, 16297 Suwon, Republic of Korea

Abstract
This study investigates the effects of soft story, short columns, heavy overhangs, pounding, and construction and workmanship quality parameters on seismic response of reinforced concrete buildings through nonlinear static and dynamic procedures. The accounted parameters are selected for their common use in rapid screening of RC buildings. The 4- and 7-story buildings designed according to pre-modern codes are used to reflect majority of the existing building stock. The relative penalty scores are employed in this study to evaluate relative importance of certain irregularities in the existing rapid seismic assessment procedures. Comparison of relative scores for the irregularities considered in this study show that the overall trend is similar. The relatively small differences may be accounted for regional construction practices. It is concluded that initial-phase seismic assessment procedures based on architectural features yield in somewhat similar results independent of their bases. However, the differences in the scores emphasize the proper selection of the method based on the regional structure characteristics.

Key Words
existing buildings; irregularity; mid-rise; seismic assessment; pounding; reinforced concrete

Address
Hayri B. Ozmen: Department of Civil Engineering, Usak University, 64200 Usak, Turkey

Mehmet Inel: Department of Civil Engineering, Pamukkale University, 20070 Denizli, Turkey

Abstract
A new higher shear deformation theory (HSDT) is presented for the thermal buckling behavior of functionally graded (FG) sandwich plates. It uses only four unknowns, which is even less than the first shear deformation theory (FSDT) and the conventional HSDTs. The theory considers a hyperbolic variation of transverse shear stress, respects the traction free boundary conditions and contrary to the conventional HSDTs, the present one presents a new displacement field which includes undetermined integral terms. Material characteristics and thermal expansion coefficient of the sandwich plate faces are considered to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic material. The thermal loads are supposed as uniform, linear and non-linear temperature rises within the thickness direction. An energy based variational principle is used to derive the governing equations as an eigenvalue problem. The validation of the present work is carried out with the available results in the literature. Numerical results are presented to demonstrate the influences of variations of volume fraction index, length-thickness ratio, loading type and functionally graded layers thickness on nondimensional thermal buckling loads.

Key Words
thermal buckling; sandwich plate; functionally graded materials; plate theory

Address
Bouchra Elmossouess, Said Kebdani: Laboratoire de mecanique applique, Universite des Sciences et Technologie d

Abstract
Ultra high performance concrete (UHPC) has aroused interest around the world owing to superior mechanical and durability properties over conventional concrete. However, the application of UHPC in practice poses difficulties due to its inherent brittleness. UHPC filled in steel tube columns (UHPC-FSTCs) are capable of restricting the brittle failure of non-reinforced UHPC columns and forming a high performance member with enhancement of strength and ductility. Currently, research on UHPC-FSTCs remains very limited and there is relatively little information about the mechanical behavior of these columns. Therefore, this study presents a review of past experimental studies to have a deeper insight into the compressive behavior of UHPC-FSTCs under axial loading on entire section and on concrete core. Based on the test results obtained from Schneider (2006) and Xiong (2012), an analysis was conducted to investigate the influence of the confinement index (

Key Words
UHPC; confinement index; strength; ductility; steel tube columns; design codes

Address
An Le Hoang: Division of Construction Computation, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam

An Le Hoang: Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam

An Le Hoang, Ekkehard Fehling: Faculty of Civil and Environmental Engineering, Institute of Structural Engineering, University of Kassel, Kurt-Wolters-Strasse 3, 34125, Kassel, Germany


Abstract
In this article, an analytical-numerical approach is presented in order to determine the dynamic response of thin plates resting on multiple elastic point supports with time-varying stiffness. The proposed method is essentially based on transforming a familiar governing partial differential equation into a new solvable system of linear ordinary differential equations. When dealing with time-invariant stiffness, the solution of this system of equations leads to a symmetric matrix, whose eigenvalues determine the natural frequencies of the point-supported plate. Moreover, this method proves to be applicable for any plate configuration with any type of boundary condition. The results, where possible, are verified upon comparison with available values in the literature, and excellent agreement is achieved.

Key Words
dynamic analysis; elastically point-supported plate; time-varying stiffness; eigenfunctions

Address
Department of Civil Engineering, Sharif University of Technology, Azadi Ave., Tehran, Iran

Abstract
The performance of bolted side-plated (BSP) beams is affected by the degree of transverse partial interaction, which is a result of the interfacial slip caused by transverse shear transfer between the bolted steel plates and the reinforced concrete beams. However, explicit formulae for the transverse shear transfer profile have yet to be derived. In this paper, a simplified piecewise linear shear transfer model was proposed based on force superposition principle and simplification of shear transfer profiles derived from a previous numerical study. The magnitude of shear transfer was determined by force equilibrium and displacement compatibility condition. A set of design formulae for BSP beams under several basic load cases was also derived. Then the model was verified by test results. A worked example was also provided to illustrate the application of the proposed design formulae. This paper sheds some light on the shear force transfer mechanism of anchor bolts in BSP beams, and offers a practical method to evaluate the influence of transverse partial interaction in strengthening design.

Key Words
reinforced concrete beam; strengthening; bolted side-plated beam; curvature factor; transverse partial interaction; transverse slip; transverse shear transfer; piecewise linear

Address
Ling-Zhi Li, Chang-Jiu Jiang: Research Institute of Structural Engineering and Disaster Reduction, College of Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China

Ray Kai-Leung Su, Sai-Huen Lo: Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong

Abstract
Rayleigh damping model is recommended in the recently developed Performance-Based Earthquake Engineering (PBEE) methodology, but this methodology does not provide sufficient information due to the complexity of the damping mechanism. Furthermore, each Rayleigh-type damping model may have its individual limitations. In this study, Rayleigh-type damping models that are used widely in engineering practice are discussed. The seismic performance of a large-span single-layer latticed dome subjected to earthquake ground motions is investigated using different Rayleigh damping models. Herein a simulation technique is developed considering low cycle fatigue (LCF) in steel material. In the simulation technique, Ramberg-Osgood steel material model with the low cycle fatigue effect is used to simulate the non-uniformly distributed material damping and low cycle fatigue damage in the structure. Subsequently, the damping forces of the structure generated by different damping models are compared and discussed; the effects of the damping ratio and roof load on the damping forces are evaluated. Finally, the low cycle fatigue damage values in sections of members are given using these damping models. Through a comparative analysis, an appropriate Rayleigh-type damping model used for a large span single-layer latticed dome subjected to earthquake ground motions is determined in terms of the existing damping models.

Key Words
viscous damping model; single-layer latticed dome; fatigue; damping force; damage

Address
Huidong Zhang, Jinpeng Wang, Xiaoshuai Zhang and Guoping Liu: Tianjin Key Laboratory of Civil Buildings Protection and Reinforcement, No.26 Jinjing Road, XiQing District, Tianjin 300384, PR China

Huidong Zhang, Jinpeng Wang, Xiaoshuai Zhang and Guoping Liu: School of Civil Engineering, Tianjin Chengjian University, No.26 Jinjing Road, XiQing District, Tianjin 300384, PR China

Abstract
Photovoltaic (PV) panels are used in high-rise buildings to convert solar energy to electricity. Due to the considerable energy consumption of high-rise buildings, applying PV technology is of great significance to energy saving. In the application of PV panels, one of the most important construction issues is the connection of the PV panel with the main structures. One major difficulty of the connection design is that the PV panel connection consists of two separate components with coupling and indeterminate dimension. In this paper, the gap element is employed in these two separated but coupled components, i.e., hook and catch. Topology optimization is applied to optimize and design the cross-section of the PV panel connection. Pareto optimization is conducted to operate the optimization subject to multiple load scenarios. The initial design for the topology optimization is determined by the common design specified by the Technical Code for Glass Curtain Wall Engineering (JGJ 102-2003). Gravity and wind load scenarios are considered for the optimization and numerical analysis. Post analysis is conducted for the optimal design obtained by the topology optimization due to the manufactory requirements. Generally, compared with the conventional design, the optimized connector reduces material use with improved structural characteristics.

Key Words
photovoltaic panel connector; topology optimization; SIMP; high-rise building; numerical analysis

Address
Xilin Lu, Jiaqi Xu, Hongmei Zhang: State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, 1239 Siping Rd, Yangpu, Shanghai, China

Peng Wei: State Key Laboratory of Subtropical Building Science, School of Civil Engineering and Transportation, South China University of Technology, 381 Wushan Rd, Tianhe, Guangzhou, Guangdong, China


Abstract
The structural designs of RC flat plates that have no flexural stiffness by boundary beams may be governed not by strength conditions but by serviceabilities. Specially, since over-loading and tensile cracking in early-aged slabs significantly increase the short- and long-term deflections of a flat plate system, a construction sequence and its impact on the slab deflections may be decisive factors in designs of flat plate systems. In this study, the procedure of simulating slab deflections with considering construction sequences, concrete cracking, and long-term effects is proposed. The proposed method is practically useful, as it can predict well the slab deflections at construction and service stages only with a few input data. The proposed method is verified by comparisons with measured results in a real-scale test.

Key Words
flat plate; deflection; construction load; reinforced concrete; deflection simulation

Address
Jae-Yo Kim: Department of Architectural Engineering, Kwangwoon University, 20 Kwangwoon-ro, Nowon-gu, Seoul 01897, Republic of Korea

Su-Min Kang: Department of Architectural Engineering, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, Chungbuk 28644, Republic of Korea


Abstract
The focus of this study were to investigate patterns between wall pressures and stresses with grain moisture of soybean and rice varieties widespread cultivated in Turkey in order to determine needed designing parameters for structure analysis in silos at filling and discharge. In this study, the wall pressures and stresses were evaluated as a function of moisture contents in the range of 8-14% and 10-14% d.b. The pressures and von Mises stresses affected as significant by the change of grain moisture content. The main cause of pressure and stress drops is changed in bulk density. Therefore is extremely important bulk density and moisture content of the product at the structural design of the silos. 4 mm wall thickness, were determined to be safe for von Mises stresses in both soybean and rice silos is smaller than 188000 kPa.

Key Words
rice; soybean; moisture content; model silo; Eurocode

Address
Department of Seed Science and Technology, Faculty of Agriculture and Natural Sciences, Abant Izzet Baysal University, Bolu, Turkey


Abstract
A low damage self-centering braced frame equipped with post-tensioning strands is capable of directing damage to replaceable butterfly-shaped fuses. This paper investigates the seismic performance of rocking braced frame under near-field pulse-like ground motions compared to far-field records. A non-linear time history analysis is performed for twelve self-centering archetypes. A sensitivity analysis is carried out to examine the influences of ground motion types and modeling parameters. Findings represent the proper efficiency of the self-centering system under both far-field and near-field pulse-like ground motions.

Key Words
self-centering braced frame archetype; far-field and near-field pulse-like ground motions; nonlinear time history analysis; engineering demand parameters

Address
Navid Rahgozar, Armin Aziminejad: Department of Structural Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

Abdolreza S. Moghadam: Department of Civil Engineering, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran

Abstract
Due to the discontinuous nature of uncertainty quantification in conventional evidence theory(ET), the computational cost of reliability analysis based on ET model is very high. A novel ET model based on fuzzy distribution and the corresponding combination rule to synthesize the judgments of experts are put forward in this paper. The intersection and union of membership functions are defined as belief and plausible membership function respectively, and the Murfhy

Key Words
evidence theory; fuzzy set; combination rule; hybrid reliability

Address
Y.R. Tao, S.Y. Duan: College of Mechanical Engineering, Hebei University of Technology, Tianjin City, 300401, China

Y.R. Tao, Q. Wang, L. Cao, Z.H.H. Huang and G.Q. Cheng: Department of Mechanical Engineering, Hunan Institute of Engineering, Xiangtan City 411101, China



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