Abstract
Bonding of carbon fiber reinforced polymer (CFRP) composites has become a popular technique for strengthening concrete structures in recent years. The bond stress between concrete and CFRP is the main factor determining the strength, rigidity, failure mode and behavior of a reinforced concrete member strengthened with CFRP. The accurate evaluation of the strain is required for analytical
calculations and design processes. In this study, the strain between concrete and bonded CFRP sheets across the notch is tested. In this paper, indirect axial tension is applied to CFRP bonded test specimen by a four point bending tests. The variables studied in this research are CFRP sheet width, bond length and the concrete compression strength. Furthermore, the effect of a crack- modeled as a notch- on the strain distribution is studied. It is observed that the strain in the CFRP to concrete interface reaches its maximum values near the crack tips. It is also observed that extending the CFRP sheet more than to a
certain length does not affect the strength and the strain distribution of the bonding. The stress distribution
obtained from experiments are compared to Chen and Teng
Key Words
CFRP; bonding strain; bonded joints; debonding.
Address
Ozgur Anil: Civil Engineering Department, Gazi University, Maltepe, Ankara 06570, Turkey
Cagatay M. Belgin: Civil Engineering Department, Gazi University, Maltepe, Ankara 06570, Turkey
M. Emin Kara: Civil Engineering Department, Aksaray University, Aksaray, Turkey
Abstract
This paper proposes a hybrid heuristic and criteria-based method of optimum design which combines the advantages of both the iterated simulated annealing (SA) algorithm and the rigorously derived optimality criteria (OC) for structural optimum design of reinforced concrete (RC) buildings under multi-load cases based on the current Chinese design codes. The entire optimum design procedure is
divided into two parts: strength optimum design and stiffness optimum design. A modified SA with the strategy of adaptive feasible region is proposed to perform the discrete optimization of RC frame structures under the strength constraints. The optimum stiffness design is conducted using OC method with the optimum results of strength optimum design as the lower bounds of member size. The proposed method is integrated into the commercial software packages for building structural design, SATWE, and
for finite element analysis, ANSYS, for practical applications. Finally, two practical frame-shear-wall
structures (15-story and 30-story) are optimized to illustrate the effectiveness and practicality of the
proposed optimum design method.
Address
Gang Li: Department of Engineering Mechanics, State Key Laboratory of Structural Analysis of Industrial Equipment, Dalian University of Technology, Dalian, 116024, China
Haiyan Lu: School of Architecture & Civil Engineering, Shenyang University of Technology, Shenyang, 110023, China
Xiang Liu: Department of Engineering Mechanics, State Key Laboratory of Structural Analysis of Industrial Equipment, Dalian University of Technology, Dalian, 116024, China
Abstract
Special-shape arch bridge for self-balance (SBSSAB) in Zhongshan City is a kind of new fashioned spatial combined arch bridge composed of inclined steel arch ribs, curved steel box girder and inclined suspenders, and the mechanical behavior of the SBSSAB is particularly complicated. The SBSSAB is aesthetic in appearance, and design of the SBSSAB is artful and particular. In order to
roundly investigate the mechanical behavior of the SBSSAB, 3-D finite element models for spatial member and shell were established to analyze the mechanical properties of the SBSSAB using ANSYS. Finite element analyses were conducted under several main loading cases, moreover deformation and
strain values for control section of the SBSSAB under several main loading cases were proposed. To ensure the safety and rationality for optimal design of the SBSSAB and also to verify the reliability of its design and calculation theories, the 1/10 scale model tests were carried out. The measured results include the load checking calculation, lane loading and crowd load, and dead load. A good agreement is achieved between the experimental and analytical results. Both experimental and analytical results have shown that the SBSSAB is in the elastic state under the planned test loads, which indicates that the SBSSAB has an adequate load-capacity. The calibrated finite-element model that reflects the as-built conditions can be
used as a baseline for health monitoring and future maintenance of the SBSSAB.
Key Words
special-shape arch bridge; self-balance; model tests; finite element method; structural safety.
Address
Pengzhen Lu: School of Civil Engineering, Southwest Jiaotong University, Chengdu, 610031, PR China
Renda Zhao: School of Civil Engineering, Southwest Jiaotong University, Chengdu, 610031, PR China
Junping Zhang: School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China
Abstract
The rigid body inertia properties of a structure including the mass, the center of gravity location, the mass moments and principal axes of inertia are required for structural dynamic analysis, modeling of mechanical systems, design of mechanisms and optimization. The analytical approaches such
as solid or finite element modeling can not be used efficiently for estimating the rigid body inertia
properties of complex structures. Several experimental approaches have been developed to determine the rigid body inertia properties of a structure via Frequency Response Functions (FRFs). In the present work two experimental methods are used to estimate the rigid body inertia properties of a frame. The first approach consists of using the amount of mass as input to estimate the other inertia properties of frame. In the second approach, the property of orthogonality of modes is used to derive the inertia properties of a frame. The accuracy of the estimated parameters is evaluated through the comparison of the
experimental results with those of the theoretical Solid Work model of frame. Moreover, a thorough discussion about the effect of accuracy of measured FRFs on the estimation of inertia properties is presented.
Key Words
rigid body; inertia properties; frequency response functions; mode shapes; transformation matrix.
Address
M.R. Ashory: Department of Mechanical Engineering, Semnan University, Semnan, Iran
A. Malekjafarian: Department of Mechanical Engineering, Semnan University, Semnan, Iran
P. Harandi: Department of Mechanical Engineering, Semnan University, Semnan, Iran
