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CONTENTS
Volume 36, Number 2, September30 2010
 

Abstract
This study deals with the viability of using a designed geometrical model consists of plane, polar coordinates (PC) and span length in the determination of bridges deformation. The data of a Tianjin Yonghe bridge located in the southern part of China as collected by RTK-DGPS technique and Accelerometer were used in the analysis. Kalman filter and fast Fourier transformation (FFT) analyses were used to determine the frequency. The results indicate that the designed plane and PC geometrical model are easy to calculate the long-time structural deformation monitoring. In addition, the observed frequency using GPS with the rate of 20 Hz doesn\'t give correction natural frequency of the observation structures.

Key Words
bridge; monitoring; RTK-DGPS; accelerometer; deformation; geometry; tower.

Address
Mosbeh R. Kaloop: Public Works and Civil Engineering Department, Faculty of Engineering, Mansoura University, 35516, El-Mansoura, Egypt
Hui Li: School of Civil Engineering, Harbin Institute of Technology, 150090, Harbin, China

Abstract
Transverse vibrations of axially moving beams with multiple concentrated masses have been investigated. It is assumed that the beam is of Euler-Bernoulli type, and both ends of it have simply supports. Concentrated masses are equally distributed on the beam. This system is formulated mathematically and then sought to find out approximately solutions of the problem. Method of multiple scales has been used. It is assumed that axial velocity of the beam is harmonically varying around a mean-constant velocity. In case of primary resonance, an analytical solution is derived. Then, the effects of both magnitude and number of the concentrated masses on nonlinear vibrations are investigated numerically in detail.

Key Words
axially moving beam; concentrated mass; method of multiple scales; nonlinear vibrations.

Address
M. Sarigul: Department of Mechanical Engineering, Celal Bayar University, Muradiye, 45140 Manisa, Turkey
H. Boyaci: Department of Mechanical Engineering, Celal Bayar University, Muradiye, 45140 Manisa, Turkey

Abstract
Maximum deflection in a beam is a design criteria and occurs generally at or close to the mid-span. Neural networks have been developed for the continuous composite beams to predict the inelastic mid-span deflections (typically for 20 years, considering cracking, and time effects, i.e., creep and shrinkage, in concrete) from the elastic moments and elastic mid-span deflections (neglecting instantaneous cracking and time effects). The training and testing data for the neural networks is generated using a hybrid analytical-numerical procedure of analysis. The neural networks have been validated for four example beams and the errors are shown to be small. This methodology, of using networks enables a rapid estimation of inelastic mid-span deflections and requires a computational effort almost equal to that required for the simple elastic analysis. The neural networks can be extended for the composite building frames that would result in huge saving in computational time.

Key Words
neural network; creep; shrinkage; composite beam; concrete cracking.

Address
Umesh Pendharkar: Department of Civil Engineering, Ujjain Engineering College, Indore Road, Ujjain (M.P.), India
Sandeep Chaudhary: Department of Structural Engineering, Malaviya National Institute of Technology, Jaipur 302017, India
A.K. Nagpal: Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 11016, India

Abstract
Coupled building control is a viable method to protect tall buildings from seismic excitation. In this study, the semi-active control of a building complex is investigated for mitigating seismic responses. The building complex is formed of one main building and one podium structure connected through Magneto-Rheological (MR) Dampers and Tuned Mass Damper. The conventional semi-active control techniques require a primary controller as a reference to determine the desired control force, and modulate the input voltage of the MR damper by comparing the desired control force. The fuzzy logic directly determines the input voltage of an MR damper from the response of the MR damper. The control performance of the proposed fuzzy control technique for the MR damper is evaluated for the control problem of a seismically-excited building complex. In this paper, a building complex that include a 14-story main building and an 8-story podium structure is applied as a numerical example to demonstrate the effectiveness of semi-active control with Magneto-Rheological dampers and its comparison with the passive control with the Tuned Mass Damper and two uncoupled buildings and hybrid semi-active control including the Tuned Mass Damper and Magneto-Rheological dampers while they are subject to the earthquake excitation. The numerical results show that semi-active control and hybrid semi-active control can significantly mitigate the seismic responses of both buildings, such as displacement and shear force responses, and fuzzy control technique can effectively mitigate the seismic response of the building complex.

Key Words
semi-active control; MR damper; Tuned Mass Damper; building complex.

Address
F. Amini: Department of Civil Engineering, Science and Technology University, Tehran 16844, Iran
R. Doroudi: Department of Civil Engineering, Science and Technology University, Tehran 16844, Iran

Abstract
The purpose of this paper is to carry out both experimental and theoretical investigations of R.C. short column subjected to horizontal forces under constant compressive loading. Eight specimens with section of 40 cm x 40 cm, height 40 cm and 50 cm and different type hoop were used of the steel cage to detect the seismic behavior of reinforced concrete short columns. Hoop spacing of column, strength of concrete, and the axial load of experiments were the three main parameters in this test. A series of equations were derived to reveal the theory could be used on analysis short column, too. Through test failure model of R.C short column being established, the type of hoop affects the behavior R.C short column in ductility rather than in strength. And the effect of analysis by Truss Model is evident and reliable in shear failure model of short column.

Key Words
short column; reinforced concrete; truss model.

Address
Chen-Yuan Chen: Department of Computer Science, National Pingtung University of Education, No. 4-18, Ming Shen Rd., Pingtung 90003, Taiwan; Doctoral Program in Management, National Kaohsiung First University of Science and Technology, Kaohsiung 811, Taiwan
Kuo-Chiang Liu: Department of Architectural Engineering, Yung-Ta Institute of Technology & Commerce, 316, Chung Shan Rd. Linlo, Pingtung 909, Taiwan
Yuh-Wehn Liu: Department of Industrial Safety and Hygiene, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan
Wehn-Jiunn Huang: Department of Architecture, National Cheng-Kung University, Tainan 701, Taiwan

Abstract
The aim of this study concerns with the construction stage analysis of highway bridges constructed with balanced cantilever method using time dependent material properties. Komurhan Highway Bridge constructed with balanced cantilever method and located on the 51st km of Elaz - Malatya, Turkey, highway over F rat River is selected as an application. Finite element models of the bridge are modelled using SAP2000 program. Geometric nonlinearity is taken into consideration in the analysis using P-Delta plus large displacement criterion. The time dependent material strength variations and geometric variations are included in the analysis. Elasticity modulus, creep and shrinkage are computed for different stages of the construction process. The structural behaviour of the bridge at different construction stages has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. As analyses result, variation of internal forces such as bending moment, axial forces and shear forces for bridge deck and column are given with detail. It is seen that construction stage analysis has remarkable effect on the structural behaviour of the bridge.

Key Words
balanced cantilever method; construction stage analysis; highway bridges; time dependent material properties.

Address
Ahmet Can Altunisik: Karadeniz Technical University, Civil Engineering Department, 61080, Trabzon, Turkey
Alemdar Bayraktar: Karadeniz Technical University, Civil Engineering Department, 61080, Trabzon, Turkey
Baris Sevim: Karadeniz Technical University, Civil Engineering Department, 61080, Trabzon, Turkey
Suleyman Adanur: Karadeniz Technical University, Civil Engineering Department, 61080, Trabzon, Turkey
Arman Domanic: Yuksel Domanic Engineering Company, 06800, Ankara, Turkey

Abstract
In this study, a hybrid search algorithm combining genetic programming with orthogonal least squares (GP/OLS) is utilized to generate prediction models for compressive strength of high performance concrete (HPC) mixes. The GP/OLS models are developed based on a comprehensive database containing 1133 experimental test results obtained from previously published papers. A multiple least squares regression (LSR) analysis is performed to benchmark the GP/OLS models. A subsequent parametric study is carried out to verify the validity of the models. The results indicate that the proposed models are effectively capable of evaluating the compressive strength of HPC mixes. The derived formulas are very simple, straightforward and provide an analysis tool accessible to practicing engineers.

Key Words
high performance concrete; genetic programming; orthogonal least square; compressive strength; formulation.

Address
S.M. Mousavi: Department of Civil Engineering, Sharif University of Technology, Tehran, Iran
A.H. Gandomi: Department of Civil Engineering, Tafresh University, Tafresh, Iran
A.H. Alavi: School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
M. Vesalimahmood: School of Mathematics, Iran University of Science and Technology, Tehran, Iran

Abstract


Key Words


Address
H.S. Chore: Department of Civil Engineering, Datta Meghe College of Engineering, Sector-3, Airoli, Navi Mumbai - 400 708, India
R.K. Ingle: Department of Applied Mechanics, Visvesvaraya National Institute of Technology, Nagpur - 440 010, India
V.A. Sawant: Department of Civil Engineering, Indian Institute of Technology (IIT), Roorkee - 247 667, India


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