Abstract
This research aims to simulate and investigate the efficiency of strengthening damaged concrete columns using concrete jacketing. The numerical program included unjacketed reference column made of ordinary RC concrete had a cross-sectional dimension of (100X100) mm and 560 mm long reinforced concrete. These cores were damaged by loading them with approximately 60% of their actual ultimate load capacities as a service load. Then, column specimens were strengthened by applying two types of self-compacting concrete SCC jacketing, which were 25 and 30 mm thick, on all four sides. Exposed to external loads at different directions vertically and horizontally simulate to the seismic load. The 3D Finite Element (FE) simulation is used to predict of three structural criteria that were selected and evaluated (deflection, stress, cracks). The results show that the failure of the strengthening columns is interesting and corresponds to the characteristics of the cracks formed in the concrete section, which was documented numerically using 3D Finite Element (FE). A significant improvement of deflection has been noted at the values at the top SECTION of columns compared to the reference sample reaching an average of up to 36.6% when using a 25 mm thick SCC-3500 jacket.
Address
Ammar Tawashi and Soleman Alamoudi: Department of Structural Engineering, Al-Baath University, Faculty of Civil Engineering, Homs, Syria
Abdulkadir Aljundi: Department of Civil Engineering, Al-Wataniya Private University, Faculty of Engineering, Hama, Syria
Abstract
Long-gauge carbon fiber line (CFL) sensors have received considerable attention in the past decade. However, there is still a need for an in-depth investigation of their measuring accuracy. This study investigates the accuracy of carbon fiber line sensors to monitor and differentiate the flexural behavior of two beams, one reinforced with steel bars alone and the other reinforced with steel and basalt fiber-reinforced polymer bars. A distributed set of long-gauge carbon fiber line, Fiber Bragg Grating (FBG), and traditional strain gauge sensors was mounted on the tensile concrete surface of the studied beams to compare the results and assess the accuracies of the proposed sensors. The test beams were loaded monotonically under four-point bending loading until failure. Results indicated the importance of using long-gauge sensors in providing useful, accurate, and reliable information regarding global structural behavior, while point sensors are affected by local damage and strain concentrations. Furthermore, long-gauge carbon fiber line sensors demonstrated good agreement with the corresponding Fiber Bragg Grating sensors with acceptable accuracy, thereby exhibiting potential for application in monitoring the health of large-scale structures.
Key Words
carbon fiber sensors; FBG sensors; flexural behavior; FRP bars; long gauge sensors; strain distribution; structural health monitoring
Address
Mohamed A. Saifeldeen and Nariman Fouad: Department of Civil Engineering, Faculty of Engineering, Aswan University, Egypt
Abstract
During the design phase, it is crucial to determine the interface stresses between the reinforcing plate and the concrete base in order to predict plate end separation failures. In this work, a simple theoretical study of interface shear stresses in beams reinforced with P-FGM and E-FGM plates subjected to an arbitrarily positioned point load, or two symmetrical point loads, was presented using the linear elastic theory. The presence of pores in the reinforcing plate distributed in several forms was also taken into account. For this purpose, we analyze the effects of porosity and its distribution shape on the interracial normal and shear stresses of an FGM beam reinforced with an FRP plate under different types of load. Comparisons of the proposed model with existing analytical solutions in the literature confirm the feasibility and accuracy of this new approach. The influence of different parameters on the interfacial behavior of reinforced concrete beams reinforced with functionally graded porous plates is further examined in this parametric study using the proposed model. From the results obtained in this study, we can say that interface stress is significantly affected by several factors, including the pores present in the reinforcing plate and their distribution shape. Additionally, we can conclude from this study that reinforcement systems with composite plates are very effective in improving the flexural response of reinforced RC beams.
Key Words
FGM plate; interfacial stresses; normal stress; porosity; RC beams; shear stress; strengthening
Address
Zahira Sadoun, Riadh Bennai and Hassen Ait Atmane: Department of Civil Engineering, Faculty of Civil Engineering and Architecture,
University Hassiba Benbouali of Chlef, Algeria;
Laboratory of Structures, Geotechnics and Risks, Department of Civil Engineering,
Hassiba Benbouali University of Chlef, Algeria
Mokhtar Nebab: Laboratory of Structures, Geotechnics and Risks, Department of Civil Engineering,
Hassiba Benbouali University of Chlef, Algeria;
Department of Civil Engineering, Faculty of Sciences,
University of M'Hamed BOUGARA Boumerdes, Algeria
Mouloud Dahmane: Department of planning and hydraulic engineering,
Higher National School of Hydraulics, Blida 9000, Algeria
Abstract
In this paper, to assess the performance of a multi-span simply supported RC bridge, the dynamic characteristics of the bridge were measured and determined by structural health monitoring and resilient assessment via operational modal analysis as well as FE modeling. Supporting finite element (FE) models were created and analyzed according to the design drawings. This study used 2D plane monitoring of locations of hole in the infill wall and used 3D health monitoring and resilient assessment. From the results of 3Dsymmetric frame, if the frame is unsymmetrical, the used model can lead to the reduction in the internal forces. The recommendations from this study is from some discrepancies observed between 2D and 3D models, if possible 3D model should be used in analyzing the real frames.
Key Words
acceleration sensor; bridge; modal analysis; structural health monitoring
Address
C.C. Hung, T.: Faculty of National Hsin Hua Senior High School, Tainan, Taiwan
T. Nguyen: Ha Tinh University, Dai Nai Ward, Ha Tinh City, Vietnam 3 National Pingtung University Education School, No.4-18, Minsheng Rd., Pingtung City, Pingtung County 900391, Taiwan
C.Y. Hsieh: National Pingtung University Education School, No.4 18, Minsheng Rd., Pingtung City,
Pingtung County 900391, Taiwan
Abstract
In cable structure maintenance, particularly for cable-stayed bridges, cable safety assessment relies on estimating cable tension. Conventionally, in Japan, cable tension is estimated from the natural frequencies of the cable using the higher-order vibration method. In recent years, dampers have been installed on cables to reduce cable vibrations. Because the higher-order vibration method is a method for damper-free cables, the damper must be removed to measure the natural frequencies of a cable without a damper. However, cables on some cable-stayed bridges have two dampers: one on the girder side and another on the tower side. Notably, removing and reinstalling the damper on the tower side are considerably more time- and labor-intensive. This paper introduces a tension estimation method for cables with two dampers, using natural frequencies. The proposed method was validated through numerical simulation and experiment. In the numerical tests, without measurement error in the natural frequencies, the maximum estimation error among 100 models was 3.3%. With measurement error of 2%, the average estimation error was within 5%, with a maximum error of 9%. The proposed method has high accuracy because the higher-order vibration method for a damper-free cable still has an estimation error of 5%. The experimental verification emphasizes the importance of accurate damper modeling, highlighting potential discrepancies between existing damper design formula and actual damper behavior. By revising the damper formula, the proposed method achieved accurate cable tension estimation, with a maximum estimation error of approximately 10%.
Key Words
cable tension estimation; damper modeling; natural frequencies; two dampers
Address
Aiko Furukawa and Kenki Goda: Department of Urban Management, Graduate School of Engineering, Kyoto University,
Kyotodaigaku-katsura, Nishikyo-ku, Kyoto-shi, Kyoto 615-8540, Japan
Tomohiro Takeichi: Kobelco Wire Company, Ltd., 10-1, Nakahama-cho. Amagasaki-shi, Hyogo 660-0091, Japan
