Journal of Civil Engineering Beyond Limits (CEBEL)

Damilola Ayodele Ogundare Familusi Ayokunle Oluwaseun Adewumi Babatunde Emmanuel Olusami Joel O.

The need to improve the strength and durability of subgrade soil in recent times has become imperative using stabilizing materials that can be sourced locally at no/or very low cost in other to reach their design life span before a major repair is required. This necessitates the improvement that could be achieved by stabilizing subgrade soil along Ede-Abeere road in Ede, Osun State with the Waste Plastic Bottle (WPB). The soil samples were collected at 1m depth at different portions along the road and stabilized with varying percentages of WPB. Laboratory tests conducted were sieve analysis, natural moisture content, specific gravity, Atterberg limit, compaction, California Bearing Ratio (CBR), and Unconfined Compressive Strength (UCS) Test. The CBR of the stabilized soil ranges from 1.28% to 12.20% with 2.5% WPB having the highest CBR value of 12.20% meeting the recommended value for unsoaked CBR of subgrade soils. However, the statistical model reliably adjudged that there is a significant relationship between the CBR values of subgrade soil-WPB mixture obtained. Thus, it is recommended that WPB at 2.5% can serve as a stabilizing material as it increases the CBR of the subgrade soil and as an effective method of disposing of WPB.

https://doi.org/10.36937/cebel.2021.004.001

Saad Issa Sarsam

Modifying asphalt binder with additives can enhance the overall physical properties of asphalt concrete. In the present investigation, an attempt has been made to use 2 % of silica fumes and 4 % of fly ash class F for modification of asphalt binder in wet process. Asphalt concrete wearing course slab samples have been prepared under roller compaction. The beam specimens of 400 mm length and 50 mm height and 63 mm width were extracted from the slab samples. The beam specimens were subjected to the four-point repeated flexural bending beam test. The flexural stiffness was calculated under three constant micro strain levels of (250, 400, and 750). The fatigue life was monitored in terms the number of load repetitions to reach the required reduction in stiffness of 50 %. It was concluded that the flexural stiffness increases by (11, and 15) %, (17.7, and 63.6) %, (57.2, and 65) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 micro strain levels respectively. However, the fatigue life increases by (40, and 72.8) %, (115, and 220.6) %, (46, and 94.6) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 micro strain levels respectively. It is recommended to use modified binder with silica fumes and fly ash in asphalt concrete to enhance the fatigue life and stiffness.

https://doi.org/10.36937/cebel.2021.004.002

Radhwane Boulkhiout Salah Messast

Soil compaction is a considerable construction activity to ensure safety and durability, notably in the transportation industry. This technique of compaction increases soil bulk density and soil strength, while decreases porosity, aggregate stability index, soil hydraulic conductivity, and nutrient availability, thus reduces soil health. Consequently, it lowers crop performance via stunted aboveground growth coupled with reduced root growth. Therefore, if the characteristics of the soil are changed, it will affect the response of the structures. In this work, the effect of improving soil characteristics by compaction techniques on the dynamic response of foundations and structures, taking into consideration the effect of soil-structure interaction was determined. The dynamic response of foundations is presented by the impedances functions, which are determined numerically by the CONAN program, based on the cone method. In addition, the response of the structure will be presented according to the lateral displacement in each level of it. This motion vector is a function of the forces in each level; for this, the equivalent static method was applied, which allows to calculate the seismic force at the base and its distribution on the height of the structure. The results obtained show the efficiency of soil densification on the seismic response of MDOF frames.

https://doi.org/10.36937/cebel.2021.004.003

Raymond Rosa Ávila Justo González Díaz Rafael A. López Ramos

To date, several studies have shown that the Earth's magnetic field suffers alterations at the local geographical location before an earthquake occur. Its study demonstrates that the Earth’s magnetic alterations at specific local geographical zone, is a local seismic precursor alerting a proximity of an earthquake with a margin of error of approximately 10%. The electromagnetic noise from background is very confusing, but that reason was necessary to identify these electromagnetic signal precursors by filtering a large amount of noise. To isolate the electromagnetic noise, was implemented a Magnetic North deflection detection in Smart Phones Magnetometers. Using it technology, was developed a mathematical algorithm that work in combination with the Smart Phones magnetometers. This research was based on the study carried out by the Department of Physics of the Faculty of Physical Sciences and Mathematics (FCFM) of the University of Chile directed by the eminent Enrique Cordado, in his paper called “Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin”.

https://doi.org/10.36937/cebel.2021.004.004

ASHISH R. AKHARE

The efficiency of traditional isolation bearings is doubted for near-field earthquakes because these bearings undergo large displacement. A comparative study of different base isolation systems of base-isolated benchmark building is carried out in the present study. The study is based on assumption that buildings are bi-directionally acted upon by near-field earthquakes for assessing their relative performance in seismic control of the benchmark building. The time history variations of important response parameters and evaluation criteria of the benchmark building has been studied for assessing the effectiveness of the isolation systems. The Shape Memory Alloy (SMA) is utilized with elastomeric bearings and friction bearings to study the effectiveness of SMA wires with different isolators. The benchmark building is modelled as a discrete linear elastic shear structure having three degrees of- freedom at each floor level. Time domain dynamic analysis of this building has been carried out with the help of constant average acceleration Newmark’s method and equilibrium of non-linear forces has been taken care by fourth order Runge-Kutta method. The comparative performance of various isolation systems has been studied with uniform and hybrid combinations. The hybrid combination of SMA supplemented bearings works out the better isolation system keeping in view of the percentage reduction in evaluation criteria for smart base-isolated benchmark building. Furthermore, it is shown that, the functionality of SMA wire is not efficient with Lead Rubber Bearing system, as it is able to control displacement but increases the acceleration, base shear, story drift and isolation forces.

https://doi.org/10.36937/cebel.2021.004.005