Abstract
This study explores the use of Fiber Bragg grating (FBG) systems as embedded sensors for monitoring strain and temperature in residential timber buildings. FBG sensors are chosen for their corrosion resistance, immunity to electromagnetic interference, and high sensitivity. They have been successfully employed as embedded sensors for real-time structural health monitoring in aerospace, automotive, and civil infrastructure applications. A proof-of-concept experimental setup has validated the system's performance and functionality. Multiple one-story and two-story scaled-down (~1:20) prototype timber buildings were constructed and placed in a wind tunnel to assess their structural performance and stability under wind speeds ranging from 0 to 150 mph. FBG sensors attached to the buildings measured strain and wavelength changes in real-time. The measured strain data can be used to estimate the load-carrying capacity and assess the building's reliability. The FBG sensors demonstrated accurate measurement and real-time monitoring of strain changes in selected structural elements during high wind speeds. Assessment results can inform condition-based maintenance, safety evaluations, and stability reports. Additionally, the system can issue real-time warnings for potential failures and damages, thereby enhancing the overall resilience of residential buildings.
Key Words
condition-based; FBG; health monitoring; hurricane; residential building, stability
Address
Abolghassem Zabihollah and Rajesh Vuddandam: Department of Mechanical, Environmental, and Civil Engineering, Tarleton state University, Stephenville, USA
Poorya Hajyalikhani: Department of Engineering Technology, Tarleton state University, Stephenville, USA
Abstract
Stone arch bridges in Japan consist of ring stones, wall stones, and filling material. Some stone arch bridges have a filling material of small size, while others have a filling material of large size. During past earthquakes, the filling material collapsed and made the wall stones to collapse together, therefore, the stability of the filling material itself seems to have an important influence on the seismic performance of stone arch bridges. However, few studies have investigated the filling material. This study focused on the effect of the filling material size on the seismic performance of stone arch bridges. The seismic behavior of stone arch bridges with large or small crushed stones as the filling material was compared through shaking table tests and numerical simulation using the refined distinct element method. The shaking table test revealed that the natural frequencies and resonance curves of stone arch bridges with large and small crushed stones are similar. However, the seismic performance was different depending on the size of crushed stone. The stone arch bridge with larger crushed stones withstood the earthquake shaking for longer time. The post-collapse appearance of the test specimen revealed that large crushed stones were more stable than small crushed stones, because large crushed stones stabilized with a steeper slope angle. The numerical simulation revealed a trend similar to that in the shaking table test. The results revealed that replacing the filling material with larger stones is expected to improve seismic performance in the maintenance of stone arch bridges.
Key Words
DEM; filling material size; seismic performance; shaking table test; stone arch bridge
Address
Aiko Furukawa and Yusuke Higashi: Department of Urban Management, Graduate School of Engineering, Kyoto University,
Kyotodaigaku-katsura, Nishikyo-ku, Kyoto-shi, Kyoto 615-8540, Japan
Abstract
There are various retrofitting strategies for strengthening damaged masonry walls. GFRPs are known as one of the new FRP-reinforcing techniques that are widely employed in masonry constructions. The purpose of this study is to evaluate the in-plane performance of damaged masonry walls which are strengthened by different GFRP configurations utilizing macro-scale numerical approach. To achieve this aim, firstly, a macro-scale numerical model of a masonry wall is simulated by finite element method in ABAQUS software and it is validated with an experimental result under a combination of a pre-compressive vertical and a horizontal cyclic loading. Secondly, according to constitutive equation-based methods, damaged areas which were observed in the experimental test are assigned to the validated model and the wall is retrofitted with six different GFRP layouts including Circuit, Vertical, Horizontal, H-shape, I-shape and Plus. Lastly, the in-plane cyclic behavior of walls is conducted and compared in terms of strength, stiffness, energy absorption and efficiency. The results revealed that the Horizontal and H-shape layouts have better performances than the Circuit and I-shape configurations. The Circuit and Horizontal configurations displayed quite similar resistance as well as H-shape and I-shape patterns. It was also observed that the Vertical configuration is the most effective GFRP layout since it provides the most enhanced in-plane resistance (51.91%) and dissipated energy (83.88%) with the highest efficiency index.
Key Words
damaged masonry walls; dissipated energy; finite element simulation; GFRP layouts; in-plane cyclic loading
Address
Nima Moradi, Mahdi Yazdani and Hanan Al Sachit: Department of Civil Engineering, Faculty of Engineering, Arak University, Arak, Iran
Abstract
In this study, two new models were developed to predict the peak axial capacity of reinforced concrete (RC) compressive members having fiber-reinforced polymer (FRP) bars at different eccentricity levels (e/h = 0 and e/h ranges from 0.08 to 1) using two distinct methods: the general regression method and the eXtreme Gradient Boosting (XGBoost) algorithm. These models were developed based on a wide range dataset comprising tests data of 308 FRP-reinforced concrete samples compiled from the existing literature. Besides, the efficiency and accuracy of the proposed models were assessed using five statistical indicators namely, coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), average absolute error (AAE), standard deviation (SD), and were equated with design codes and previously proposed formulas in the literature. The findings demonstrate that the suggested estimation models were suitable for capturing the axial capacity of FRP-RC compressive members. Particularly, the XGBoost model exhibited outstanding performance with a high R2 value of 0.98 and minimal RMSE, MAE, AAE and SD values of 259.05 kN, 144.36 kN, 0.11, and 0.14 respectively, indicating excellent efficiency and accuracy compared to both the empirical model proposed and other existing models. This outcome highlights the ability of machine learning models to estimate the axial capacity of FRP-RC compressive members. Consequently, the XGBoost model offers a viable alternative method to empirical models for design applications.
Address
Sarra Sendjasni and Mohammed Berradia: Department of Civil Engineering, Laboratory of Structures, Geotechnics and Risks (LSGR), Hassiba Benbouali University of Chlef, B.P 78C, Ouled Fares Chlef 02180, Algeria
Riad Benzaid: Department of Civil Engineering, L.G.G. Research laboratory, Jijel University, BP.96 Ouled Issa,
Jijel-18000, Algeria
Ali Raza: Department of Civil Engineering, University of Engineering and Technology Taxila, 47080, Pakistan
Abstract
Delamination cracks are detected often in multilayered beam structures during lifetime. This fact raises concerns about serviceability of multilayered structures. Apparently, there is a need for tools to adequately predict whether further functioning of these structures is safe. Developing of such tool is subject of this work. In particular, the work is concerned with the problem of delamination analysis of a multilayered beam structure subjected to bending at a constant velocity (the angle of rotation of the free end of the lower arm of the delamination crack varies with time at a constant velocity). The layers of the beam are made of non-linear elastic structural materials that exhibit smooth inhomogeneity along the thickness. Therefore, the material parameters of the non-linear constitutive law are continuous function of the transversal coordinate, z. The method of the integral J is used for analyzing the delamination behavior of the beam. The analysis takes into account the bending velocity. A check-up of the analysis is performed by deriving the strain energy release rate (SERR). The analysis is applied for determining the safe velocity of the angle of rotation. The safe delaminaton length and the time of safe functioning of the beam structure are determined too. The effect of additional support introduced in the beam on the time of safe functioning is also evaluated.
Key Words
analysis; delamination; material inhomogeneity; multilayered structure; safety; serviceability
Address
Victor I. Rizov: Department of Technical Mechanics, University of Architecture, Civil Engineering and Geodesy,
1 Chr. Smirnensky blvd., 1046 – Sofia, Bulgaria
