Abstract
Various efforts have been made to reduce the weight of concrete slabs while preserving their flexural strength. This will result in reducing deflection and allows the utilization of longer spans. The top zone of the slab requires concrete to create the compression block for flexural strength, and the tension zone needs concrete to join with reinforcing for flexural strength. Also, the top and bottom slab faces must be linked to transmit stresses. Voided slab systems were and are still used to make long-span slab buildings lighter. Eight slab specimens of (1000*1000 mm2) were cast and tested as two-way simply supported slabs in this research. The tested specimens consist of one solid slab and seven voided slabs with the following variables (type of slab solid and voided), thickness of slab (100 and 125 mm), presence of steel fibers (0% and 1%), and the number of GFRP layers). The voids in slabs were made using high-density polystyrene of dimensions (200*200*50 mm) with a central hole of dimensions (50*50*50 mm) at the ineffective concrete zones to give a reduction in weight by (34% to 38%). The slabs were tested as simply supported slabs under partial uniform loading. The results of specimens subjected to monotonic loading show that the combined strengthening by steel fibers and GFRP sheets of the concrete specimen (V-125-2GF-1%) shows the least deflection, deflection (4.6 mm), good ultimate loading capacity (192 MPa), large stiffness at cracking and at ultimate (57 and 41.74) respectively, more ductility (1.44), and high energy absorption (1344.83 kN.mm); so it' s the best specimen that can be used as a voided slab under this type of loading.
Address
Adel A. Al-Azzawi and Shahad H. Mtashar: Department of Civil Engineering, College of Engineering, Al-Nahrain University, Jadriya, Baghdad, Iraq
Abstract
Despite the significance of ports as critical economic infrastructure, the berth facilities usually deteriorate due to heavy loading, unloading, aging, environmental weather conditions, marine growths, and lack of efficient maintenance management. Marine berths require proactive maintenance management to limit deterioration and defects as no berth facility is maintenance-free. Thus, delay in carrying out maintenance work for the marine berths can be devastating to the operational process involving ship entry, loading, and unloading operations. The aim of this research is to coordinate both operations work, and maintenance works that take place inside the berth of a local industrial port in Saudi Arabia, by developing a novel framework that integrates both works without affecting the efficiency and functionality of the berth. The study focused on defining the operational process of the port and identifying the elements with direct and indirect effects. In addition to determining the priority for the entry of ships inside the berth, it also identified the factors involved in designing a framework that included maintenance work as a component of the monthly berth occupancy schedule. By applying a mathematical model, a framework was established, which includes all the important elements of the process. As a result of the mathematical method formulation process, a database was designed that organizes and coordinates the operations of all berths within the port. This creates time to carry out the required maintenance work monthly as well as ease of coordination with the contractors responsible for the implementation of those works.
Key Words
berth maintenance; container terminal; industrial seaport; maintenance management; maritime transportation; time windows
Address
Mohammed E. Shaawat, Abdullah Binomar and Abdulaziz S. Almohassen:Department of Building Engineering, College of Architecture and Planning, Imam Abdulrahman Bin Faisal University, 31451 Dammam, Kingdom of Saudi Arabia
Khalid Saqer. Alotaibi and Mahmoud Sodangi: Department of Civil and Construction Engineering, College of Engineering, Imam Abdulrahman Bin Faisal University, 31451 Dammam, Kingdom of Saudi Arabia
hmad Aftab: Department of Traffic and Transportation Engineering, College of Engineering, Imam Abdulrahman Bin Faisal University, 31451 Dammam, Kingdom of Saudi Arabia
Abstract
Damage monitoring is a prerequisite step to ensure the safety and performance of concrete structures. Smart aggregate (SA) technique has been proven for its advantage to detect early-stage internal cracks in concrete. In this study, a 1-D CNN-based method is developed for autonomously classifying the damage feature in a concrete anchorage zone using the raw impedance signatures of the embedded SA sensor. Firstly, an overview of the developed method is presented. The fundamental theory of the SA technique is outlined. Also, a 1-D CNN classification model using the impedance signals is constructed. Secondly, the experiment on the SA-embedded concrete anchorage zone is carried out, and the impedance signals of the SA sensor are recorded under different applied force levels. Finally, the feasibility of the developed 1-D CNN model is examined to classify concrete damage features via noise-contaminated signals. The results show that the developed method can accurately classify the damaged features in the concrete anchorage zone.
Key Words
1-D CNN; anchorage zone; concrete damage; convolutional neural network (CNN); damage classification; deep learning; impedance-based monitoring; smart aggregate
Address
Quoc-Bao Ta, Ngoc-Lan Pham and Jeong-Tae Kim: Department of Ocean Engineering, Pukyong National University, Nam-gu, Busan 48513, Republic of Korea
Quang-Quang Pham; Bridge and Road Department, Danang Architecture University, Da Nang 550000, Vietnam
Abstract
Structural health monitoring and damage detection are essential for assessing, maintaining, and rehabilitating structures. Most of the existing damage detection approaches compare the current state structural response with the undamaged vibrational structural response, which is unsuitable for old and existing structures where undamaged vibrational responses are absent. One of the approaches for existing structures, numerical model updating/inverse modelling, available in the literature, is limited to numerical studies with high-end software. In this study, an attempt is made to study the effectiveness of the model updating technique, simplify modelling complexity, and economize its usability. The optimization-based detection problem is addressed by using programmable open-sourced code, OpenSees and a derivative-free optimization code, NOMAD Modal analysis is used for damage identification of beam-like structures with several damage scenarios. The performance of the proposed methodology is validated both numerically and experimentally. The proposed method performs satisfactorily in identifying both locations and intensity of damage in structures.
Key Words
damage detection; optimization; model updating; structural health monitoring; vibrational analysis
Address
Devesh K. Jaiswal, Goutam Mondal, Suresh R. Dash and Mayank Mishra: School of Infrastructure, Indian Institute of Technology Bhubaneswar, Bhubaneswar-752050, India
Abstract
Seismic regulations have been updated from time to time to accommodate an increase in seismic hazards. Comparison of seismic fragility of the existing bridges in Indonesia from different historical periods since the era before 1990 will be the basis for seismic assessment of the bridge stock in Indonesia, most of which are located in earthquake-prone areas, especially those built many years ago with outdated regulations. In this study, seismic fragility curves were developed using incremental non-linear time history analysis and more holistically according to the actual strength of concrete and steel material in Indonesia to determine the uncertainty factor of structural capacity, Bc. From the research that has been carried out, based on the current seismic load in SNI 2833:2016/Seismic Map 2017 (7% probability of exceedance in 75 years), the performance level of the bridge in the era before SNI 2833:2016 was Operational-Life Safety whereas the performance level of the bridge designed with SNI 2833:2016 was Elastic – Operational. The potential for more severe damage occurs in greater earthquake intensity. Collapse condition occurs at As = FPGA x PGA value of bridge Era I = 0.93 g; Era II = 1.03 g; Era III = 1.22 g; Era IV = 1.54 g. Furthermore, the fragility analysis was also developed with geometric variations in the same bridge class to see the effect of these variations on the fragility, which is the basis for making bridge risk maps in Indonesia.
Address
Veby Citra Simanjuntak:Structural Engineering Research Group, Faculty of Civil and Environmental Engineering,
Bandung Institute of Technology, Indonesia, Ganesha 10, Bandung 40132, Indonesia;
Ministry of Public Works and Housing, Pattimura No. 20, Kebayoran Baru, Jakarta Selatan 12110, Indonesia
Iswandi Imran,
Muslinang Moestopo and Herlien D. Setio: Structural Engineering Research Group, Faculty of Civil and Environmental Engineering,
Bandung Institute of Technology, Indonesia, Ganesha 10, Bandung 40132, Indonesia
open access
