Journal of Civil Engineering Beyond Limits (CEBEL)

Saad Issa Sarsam

The asphalt concrete mixture is prone to environmental issues such as moisture damage and ageing. This may exhibit a great significance in the service performance of asphalt concrete pavement mixtures which may be more susceptible to many types of early distresses throughout its fatigue life. In the present investigation, asphalt concrete mixtures were prepared and compacted with the aid of laboratory roller compaction into a slab samples. optimum binder content was implemented. Extra samples were prepared at higher and lower binder content of 0.5 % (above and below the optimum). Asphalt concrete beam specimens were obtained from the prepared slab samples with the aid of a diamond saw. Part of the Asphalt concrete beam specimens were tested under four point’s repeated flexural stresses after practicing moisture damage while another part was subjected to long term ageing. The rate of change in the flexural strength was monitored and compared among the various testing conditions at 20 ºC environment and under constant micro-strain level of 750. It was observed that the lower flexural strength was observed for moisture damaged specimens while higher flexural strength could be detected for aged specimens as compared with the control mixtures. The binder content exhibits a significant influence on flexural strength of the asphalt concrete specimens since it declines significantly at higher or lower binder content as compared with that of specimens prepared at the optimum.

https://doi.org/10.36937/cebel.2023.1804

Christopher Ehizemhen Emmanuel Ufuah Engr Agashua Lucia O

Copper and zinc concentrations in water- physiques in five sites at Ikpoba River, Nigeria was ascertained in both arid and wet season by obvious spectrophotometric technique and modelled for contagion and health risks scrutiny. Result shown that copper means for all sites ranges from 1.06 ± 2.09 and 1.34 ± 3.27 in dry and wet seasons respectively, while zinc for wet season ranged from 2.13 ± 2.9 and 2.06 ± 3.01 throughout dry season. Box and whisker plots display a variable’s locality, expanse at a glance as well as give specific clue about data's symmetry as well as skewness. All water bodies sites in dry season were slightly contagion in dry season and dry period order are; site 5 < site 2 < site 3 < site 1 < site 4. Wet season investigated followed the same pattern, for all water bodies contagion values are also slightly contagion with locations order as site 3 > site 2 > site 4 > site 1 > site 5. This signifies that throughout the year the water physiques are too enhanced, thus is at high risks of eutrophication. The spatial distribution map showed Copper /Zinc ratio dispersion of 14.20:0.16, also C:Z was highest at 14.20@0.00, followed by 13.04@0.05 with low impact at 5.08@0.16 The outcomes from the assessed non-carcinogenic hazard quotient and index via the scrutiny pathways on youngster and elderly revealed that children (4.961 & 3.394) mostly had high HI compared to adults (2.539 & 2.207) during wet and dry season respectively.

https://doi.org/10.36937/cebel.2023.1808

Md. Ibrahim Mostazid Mst. Shahanaj Parvin Appel Mahmud Nazmun Nahar

Bangladesh is at high risk of earthquakes due to its geographic location. Earthquakes can cause widespread damage to buildings and infrastructure, as well as significant loss of life, due to the sudden release of energy in the form of seismic waves. Therefore, identifying and assessing the vulnerability of existing buildings is crucial for earthquake risk reduction. Hajee Mohammad Danesh Science and Technology University (HSTU) is situated just 13 kilometers from Dinajpur, which falls under zone II, a medium-risk zone according to the Bangladesh National Building Code (BNBC, 1993). This study aims to evaluate the seismic vulnerability of HSTU's existing buildings. A widely used seismic assessment technique, the Turkish two-level assessment procedure, was employed in this study to identify seismically vulnerable buildings. A total of 79 buildings were surveyed at level I, considering vulnerability parameters such as soft storey, heavy overhanging, pounding effect, topographic effect, short column, shape of building, number of storeys, apparent quality of building, and soil type. Based on these parameters, performance scores were assigned to each building, and they were classified into damage categories of safe, moderate, and unsafe at level I. Digital photographs of each building from at least two directions were taken for easy identification. All 79 buildings on the HSTU campus were found to be safe after the level I survey. Level II assessment was conducted on only one building to validate the level I findings, and it was classified as a low-risk structure. A significant outcome of this study is the identification of damage categories and the potential to reduce seismic risk at HSTU by creating a comprehensive building inventory.

https://doi.org/10.36937/cebel.2023.1887

Elif Agcakoca

In this article, experimental and finite element analysis studies were carried out at different impact heights of steel beams with different geometric cross-sections. The behavior of elements with varying cross-sectional properties was examined when subjected to hammer loads dropped from different heights. In the experimental study, boundary conditions were established using a 2000 mm long rectangular cross-section beam element with pin and roller supports. The behavior of the steel beam under impact load was analyzed using Abaqus Explicit three-dimensional finite element models. Subsequently, a validation process ensuring convergence was performed before conducting a parametric study. 6 finite element models were constructed for the parametric study, comprising circular and ellipse-section steel elements with approximately equivalent unit weights. The cross-sectional geometry and hammer height were varied while keeping the boundary conditions consistent with the samples examined. As the height of the hammer drop increased, the displacement value, Von-Mises stress, and PEEQ (plastic equivalent strain) values of the elements also increased. When transitioning the cross-sectional shape of the beam element from a circle to an ellipse at a constant hammer height, it resulted in a decrease in the displacement value, Von-Mises stress, and PEEQ values. The results indicate that the maximum displacement, highest stress, and PEEQ value are observed in the E#2000 scenario. Similarly, the smallest displacement, lowest stress, and PEEQ value are exhibited in the C#1400 case.

https://doi.org/10.36937/cebel.2023.1891