Journal of Civil Engineering Beyond Limits (CEBEL)

Enrique Martinez-Rueda Oday AL-MAMOORI

Yield devices of “C” shape, known as C-devices, supplement the energy dissipation sources when installed in earthquake resistant structures. However, the explicit modelling of C-devices is time consuming. Accordingly, this paper presents a new reliable methodology to define and calibrate an equivalent uniaxial inelastic spring that effectively reproduces the expected hysteretic response of a C-device. The shape of the C-device under study resembles that of a rectangular portal frame with circular interior corner transitions to avoid stress concentration and to control the extension of the dissipative region. The characterization of the properties of the equivalent spring is supported by both, finite element (FE) analyses of a family of C-devices and by experimental validation. Two types of FE models are used to predict the response of the C-device. A simple FE model idealizes the device as an inelastic frame with pinned supports, whereas the more elaborate model analyses the device as a C-shaped inelastic plate under in-plane actions and explicitly reproduces the boundary conditions of the plate at the device connections. Results indicate that the FE analysis results and those obtained with the equivalent inelastic spring are in a good agreement with experimental tests for monotonic and reversed cyclic loading.

https://doi.org/10.36937/cebel.2022.1579

Saad Issa Sarsam

One of major asphalt pavement distresses is the moisture damage which influences the degradation of the viscoelastic properties of the mixture. The present work assesses the impact of practicing micro-crack healing on the viscoelastic properties of moisture damaged asphalt concrete. Roller compacted slab samples of asphalt concrete were prepared at optimum binder content. Beam specimens were obtained from the slab samples and subjected to moisture damage. Part of the asphalt concrete beam specimens were then tested under dynamic flexural stresses, while another part of the asphalt concrete beams was subjected to micro-cracks healing process using external heating at 60° C for 120 minutes, then tested under the dynamic flexural stresses. The viscoelastic properties of asphalt concrete in terms of permanent deformation, flexural stiffness, phase angle, and cumulative dissipated energy were monitored and compared among both testing conditions. It was observed that a significant increase in the flexural stiffness could be observed after healing. The increase in the phase angle after healing is significant at the early stages of loading. Higher cumulative dissipated energy could be observed for mixture which had practiced micro-crack healing. It was concluded that healing process does not exhibit positive influence on permanent deformation of moisture damaged asphalt concrete. A significant increase of 41.6 % in the flexural stiffness could be observed after healing after the first load repetition as compared with the mixture before healing. The permanent deformation after healing is higher by 22 % at failure as compared with that of mixture before healing.

https://doi.org/10.36937/cebel.2022.1703

Nirmal Chandra Roy Md. Belal Hossain Md. Saifullah Mansur Md. Sifat Ahmed1 Md. Shaidur Rahaman

In various studies, driver fatigue is a major contributing factor to fatal road accidents. In Bangladesh, road accidents and fatalities increased by 13.43% and 15.7% respectively, in 2021 compared with 2020. It is growing substantially and frighteningly, resulting in a significant loss of life and resources. Drivers in Bangladesh are more likely to have fatigue-related accidents, which increases their vulnerability on the social and economic aspects as well as their probability of becoming disabled. This study was conducted in three districts (Dinajpur, Gaibandha, Rajshahi) which are northwest region of Bangladesh. In these, study 103 drivers of long route above 400km were interviewed through discussions to gather information on drivers, such as their age, driving history, economic conditions, the times of day when they are most likely affected by fatigue, causes of fatigue, and suggestions from their perspective. The study found 17 factors and the most important factors are lack of sleep (17%), traffic jams (8%), police harassment (8%), bad road conditions (13%), daytime driving restriction (1%) and drug consumption (1%). This study will assist policymakers in creating an environment to adopt appropriate preventive measures to reduce fatigue induced accidents.

https://doi.org/10.36937/cebel.2022.1726

Osama Amer Hany el-Kady Ahmed Hassan Ali Hesham Ahmed Haggag Ashraf Shawky

Using Glass fiber-reinforced polymer (GFRP) bars as a replacement for conventional steel bars is one of the most potential solutions to steel-corrosion-related problems in concrete. Their durability and high strength-to-weight ratio make them a cost-effective and applicable alternative to conventional steel bars. This study investigates the characteristic behavior of concrete shear walls reinforced with steel, GFRP, and a hybrid scheme of steel and GFRP bars under seismic loading. Six full-scale RC shear walls with an aspect ratio of 3.25 were tested under pseudo-static reversed-cyclic lateral load to investigate the potential of a hybrid reinforcement scheme of steel-GFRP to improve the seismic behavior of slender RC shear walls. The overall performance of each tested wall was characterized by investigating the hysteretic response, crack propagation, lateral load capacity, and energy dissipation behavior. Furthermore, the effects of the GFRP web reinforcement ratio on different behavioral aspects are also investigated. The results indicated that the GFRP-reinforced concrete cantilever walls had an elastic behavior with recoverable deformation up to more than 80% of its ultimate lateral strength. A considerable enhancement in the self-centering capacity of hybrid GFRP-steel reinforced walls was observed, which helped to mitigate the experienced concrete damage. Moreover, higher displacement capacity, increased lateral strength, and equivalent viscous damping coefficient were attained with the GFRP web reinforcement ratio.

https://doi.org/10.36937/cebel.2022.1737

Barış BAYRAK Mahmut Kılıç Mahyar Maali Oğuzhan Çelebi Abdulkadir Cüneyt Aydın

The reinforced concrete (RC) shear walls are widely used to serve as the primary lateral load-resisting member in the high-rise buildings. An experimental investigation and analysis of the mechanical behaviour of hybrid fiber reinforced self-compacting concrete (HFRSCC) shear walls under pure torsion moment is presented in this paper. The nine HFSCC shear walls with the same cross-sectional and longitudinal reinforcement ratio were tested under pure torsion moment and no axial load. The effect of hybrid fiber ratio and horizontal reinforcement amount and aspect ratio on the failure characteristics, torsional behaviour, energy dissipation capacity of squat shear walls was studied. Result indicate that both hybrid and horizontal reinforcement ratio are increased the maximum torsional moment capacity and twist angle and that the hybrid fiber ratio is the key parameter that determines the failure mode of the HFSCC shear walls.

https://doi.org/10.36937/cebel.2022.1745