Abstract
This paper presents a theory concerning the beam element subjected to an eccentric rolling disk (or simply called the eccentric-disk-loaded beam element) such that the dynamic responses of a beam subjected to an eccentric rolling disk with its inertia force, Coriolis force and centrifugal force considered can be easily determined. To this end, the property matrices of an eccentric-disk-loaded beam element are firstly derived by means of the Lagrange\'s equations. Then, the overall property matrices of the entire vibrating system are determined by directly adding the property matrices of the eccentric-disk-loaded beam element to the overall ones of the entire beam itself. Finally, the Newmark direct integration method is used to solve the equations of motion for the dynamic responses of a beam subjected to an eccentric rolling disk. Some factors relating to the title problem, such as the eccentricity, radius and rotating speed of the rolling disk, and the Coriolis force and centrifugal force induced by the rolling disk are investigated. Numerical results reveal that the influence of last factors on the dynamic responses of the pinned-pinned beam is significant except the centrifugal force.
Key Words
eccentric rolling disk; eccentricity; rotating speed; Coriolis force; centrifugal force
Address
Jia-Jang Wu : Department of Marine Engineering, College of Maritime, National Kaohsiung Marine University, No. 482,Jhongjhou 3rd Road, Cijin District, Kaohsiung City 80543, Taiwan
Abstract
This paper presents a framework for seismic damage evaluation for Algerian buildings adapted from HAZUS approach (Hazard-United States). Capacity and fragility curves were adapted to fit the Algerian building typologies (Reinforced Concrete structures, Confined or Non-Confined Masonry, etc). For prediction purposes, it aims to estimate the damages and potential losses that may be generated by a given earthquake in a prone area or country. Its efficiency is validated by comparing the estimated and observed damages in Boumerdes city, in the aftermath of Boumerdes earthquake (Algeria: May 21st 2003; Mw = 6.8). For this purpose, observed damages reported for almost 3,700 buildings are compared to the theoretical predictions obtained under two distinct modelling of the seismic hazard. In one hand, the site response spectrum is built according to real accelerometric records obtained during the main shock. In the other hand, the effective Algerian seismic code response spectrum (RPA 99) in use by the time of the earthquake is considered; it required the prior fitting of Boumerdes site PGA (Peak Ground Acceleration) provided by Ambraseys\' attenuation relationship.
Key Words
Algerian buildings; HAZUS; seismic damage; Boumerdes earthquake; Algerian seismic code
Address
Mehdi Boukri, Mohammed Naboussi Farsi, Mohamed Belazougui : National Earthquake Engineering Research Centre (CGS), Rue Kaddour RAHIM, BP 252, Hussein-Dey, Algiers, Algeria
Mehdi Boukri : Civil Engineering Department, Saad Dahlab University, Blida, Algeria
Ahmed Mebarki : Universite Paris-Est, Laboratoire Modelisation et Simulation Multi Echelle, MSME, UMR 8208 CNRS, 5 Bd Descartes, 77454 Marne-La-Vallee, France
Abstract
In this paper, a new efficient optimization algorithm called Teaching–Learning-Based Optimization (TLBO) is used for the least weight design of trusses with continuous design variables. The TLBO algorithm is based on the effect of the influence of a teacher on the output of learners in a class.
Several truss structures are analyzed to show the efficiency of the TLBO algorithm and the results are compared with those reported in the literature. It is concluded that the TLBO algorithm presented in this study can be effectively used in the weight minimization of truss structures.
Key Words
teaching-learning-based optimization; truss structure; weight minimization
Address
Tayfun Dede : Department of Civil Engineering, Karadeniz Technical University, 61080, Trabzon, Turkey
Yusuf Ayvaz : Department of Civil Engineering,Yildiz Technical University, 34220, Esenler, İstanbul, Turkey
Abstract
In this paper, an improved version of particle swarm optimization based optimum design algorithm (IPSO) is presented for the steel grillage systems. The optimum design problem is formulated considering the provisions of American Institute of Steel Construction concerning Load and Resistance Factor Design. The optimum design algorithm selects the appropriate W-sections for the beams of the grillage system such that the design constraints are satisfied and the grillage weight is the minimum. When an improved version of the technique is extended to be implemented, the related results and convergence performance prove to be better than the simple particle swarm optimization algorithm and some other metaheuristic optimization techniques. The efficiency of different inertia weight parameters of the proposed algorithm is also numerically investigated considering a number of numerical grillage system examples.
Key Words
optimum structural design; particle swarm optimization; minimum weight; search technique; combinatorial optimization; grillage systems
Address
Ferhat Erdal : Department of Civil Engineering, Akdeniz University, Antalya, Turkey
Erkan Doğan : Department of Civil Engineering, Celal Bayar University, Manisa, Turkey
Mehmet Polat Saka : Department of Civil Engineering and Architecture, University of Bahrain, Bahrain
Abstract
Compared with pavement structures of ordinary road sections, pavement structures in the intersection are exposed to more complex traffic characteristics which may exacerbates pavement distresses such as fatigue-cracking, shoving, shear deformation and rutting. Based on a field survey about traffic characteristics in the intersection conducted in Shanghai China, a three dimensional dynamic finite-element model was developed for evaluating the mechanistic responses in the pavement structures under different traffic characteristics, namely uniform speed, acceleration and deceleration. The results from this study indicated that: (1) traffic characteristics have significant effects on the distributions of the maximum principal strain (MPS) and the maximum shear stress (MSS) at the pavement surface; (2) vehicle acceleration or deceleration substantially impact the MPS and MSS at pavement surface and could increase the magnitude of them by 20 percent to 260 percent; (3) in the vertical direction, with the increase of vehicle deceleration rate, the location of the MPS peak value and the MSS peak value changes from the sub-surface layer to the pavement surface.
Key Words
intersection area; traffic characteristic; dynamic finite element; maximum principal strain; maximum shear stress
Address
Qun Yang and Jingwang Dai : Key Laboratory of Road and Traffic Engineering of the Ministry of Education, Tongji University, Shanghai 201804, China
Abstract
Disposal of construction wastes poses major challenge to the municipal administration in the developing countries. At the same time new developments in these countries are unscrupulously exploiting the natural resources. The sustainable development requires judicious and careful utilization of natural resources. In this context, reuse of construction and demolition waste can save the global natural resources to greater extent. In this work the bricks and concrete waste from construction sites were crushed to the desired sizes and mixed in various proportions to study its properties in the concrete both in fresh and hardened states. Six mixes of natural and recycled aggregates were used to make the coarse aggregates for the concrete. From each mix nine cylinders were cast, which were tested at 7,14 and 28 days. The properties of concrete with recycled aggregates were compared with the control mix having natural aggregates. The nominal ratio of cement sand and coarse aggregates were kept at 1:2:4 by weight for all mixes. The tests have shown that concrete with recycled aggregates made from old concrete and brick bats provide greater opportunities for reuse of construction wastes in concrete.
Key Words
sustainable development; concrete; construction wastes; recycled aggregates
Address
Attaullah Shah : Project Directorate, Allama Iqbal Open University, Islamabad, Pakistan
Irfan U. Jan : National Centre of Excellence in Geology, University of Peshawar, Pakistan
Raza U. Khan : National Agriculture Research Centre, Islamabad, Pakistan
Ehsan U. Qazi : National Institute of Science and Technical Education (NISTE), Islamabad, Pakistan
Abstract
Geometrically non-linear axisymmetric bending of a shallow spherical shell with a clamped or a simply supported edge under axisymmetric load was investigated numerically. The partial load was introduced by the Heaviside step function, and the solution was obtained by the finite difference and the Newton-Raphson methods. The thickness of the shell was considered to be uniform and the material was assumed to be homogeneous and isotropic. Sensitivity analysis was made for three geometrical parameters. The accuracy of the algorithm was checked by comparing the central deflection, the radial membrane stress at the edge, or the transverse shear force with the solutions of plates and shells in the literature and good agreement was obtained. The main findings of the study can be outlined as follows: (i) If the shell is fully
loaded the central deflection of a clamped shell is larger than that of a simply supported shell provided that the shell is not very shallow, (ii) if the shell is partially loaded the central deflection of the shell is sensitive
to the parameters of thickness, depth, and partial loading but the influence of the boundary conditions is negligible.
Key Words
shell, non-linear, partial loading, bending, plate
Address
Murat Altekin and Receb F. Yukseler : Department of Civil Engineering, Yildiz Technical University, 34220, Esenler, Istanbul, Turkey
Abstract
The study presents the results of an experimental program concerning the shear force transfer between reinforced concrete (RC) jackets and existing columns with damages. In order to investigate the effectiveness of the repair method applied and the contribution of each shear transfer mechanism of the interface. It includes 22 concrete columns (core) (of 24,37MPa concrete strength) with square section (150mm side, 500 mm height and scale 1:2). Ten columns had initial construction damages and twelve were subjected to initial axial load. Sixteen columns have full jacketing at all four faces with 80mm thickness (of 31,7MPa concrete strength) and contain longitudinal bars (of 500MPa nominal strength) and closed stirrups spaced at 25mm, 50mm or 100mm (of 220MPa nominal strength). Fourteen of them contain dowels at the interface between old and new concrete. All columns were subjected to repeated (pseudo-seismic) axial compression with increasing deformation cycles up to failure with or without jacketing. Two load patterns were selected to examine the difference of the behavior of columns. The effects of the initial damages, of the reinforcement of the interface (dowels) and of the confinement generated by the stirrups are investigated through axial- deformation (slip) diagrams and the energy absorbed diagrams. The results indicate that the initial damages affect the total behavior of the column and the capacity of the interface to shear mechanisms and to slip: a) the maximum bearing load of old column is decreased affecting at the same time the loading capacity of the jacketed element, b) suitable repair of initially damaged specimens increases the capacity of the jacketed column to transfer load through the interface.
Key Words
concrete jacket; initial damage; force transfer; repair and strengthening
Address
Achillopoulou D.V. and Karabinis A.I.: Reinforced Concrete Laboratory, Civil Engineering Department, Polytechnic School, Democritus University of Thrace, Vas. Sofias 12, 67100, Xanthi, Greece
