A Disaster Resilient Road: Effects of Fines on Density and Shear Strength of Sands
Md. Shahin,
Md. Mehedi Hasan Khan,
Md. Niamul Bari
Issue:
Volume 6, Issue 2, June 2020
Pages:
38-43
Received:
2 March 2020
Accepted:
16 March 2020
Published:
23 April 2020
Abstract: During a massive flood or earthquake, the roads are mainly damaged due to the looseness of the subgrades. In recent times for any new constructions of roads and embankments the subgrades mainly constructed with the sand filling. It is difficult to achieve the desired degree of compaction beyond a certain limit. That’s why the bases (subgrades) become loose. This study aims to overcome the situation by increasing compaction and shear strength properties of sand filling. In this paper, an intensive laboratory investigation of fines with sands is investigated by a series of the proctor test and direct shear test. In this study, fines were mixed with the sand samples in a proportion of 10%, 20%, 30%, 45% and 55% to examine the effect on maximum dry density. Tests indicated that 45 to 55% fines with sands having different Fineness Modulus (FM), the Maximum Dry Density (MDD) of the sand can be increased up to 18 to 26% depending on FM. The results revealed that the density and shear strength (cohesion) of sand both increase significantly with the addition of fines with it up to a certain percentage. This increment in MDD and shear strength makes the bases (subgrades) stronger and stable. This result can be used in disaster resilient road or embankment construction and also for the structures having a shallow foundation.
Abstract: During a massive flood or earthquake, the roads are mainly damaged due to the looseness of the subgrades. In recent times for any new constructions of roads and embankments the subgrades mainly constructed with the sand filling. It is difficult to achieve the desired degree of compaction beyond a certain limit. That’s why the bases (subgrades) beco...
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Maritime Labour Demand for LNG Carriers Operations in Nigeria: Augmented Trend Analysis
Nwokedi Theophilus Chinonyerem,
Okafor Cajethan Onyedikachi,
Hussani Yusuf Kodo,
Johnson Mathew Ndubuisi,
Gbasibo Lawrence Addah
Issue:
Volume 6, Issue 2, June 2020
Pages:
44-51
Received:
28 March 2020
Accepted:
16 April 2020
Published:
11 May 2020
Abstract: The study analyzed the maritime labour demand for LNG carriers operations in Nigeria using augmented trend analysis. The objectives of the study among other things were to estimate the demand for maritime labour for LNG carriers operations in Nigeria and to estimate the instantaneous rates of change (IROC) as well as the average rate of change (AROC) for maritime labour demand for LNG carriers operations in Nigeria between 1998 –2016. Historical design approach was adopted and data on maritime labour demand (Dml) and tonnages of seaborne LNG trade between 1998 -2016 were sourced from the annual statistical reports of the Nigeria Liquefied Natural Gas (NLNG) company and Nigeria Petroleum Corporation (NNPC) 2017 editions, covering a period of 19years. The data obtained was analyzed using trend analysis augmented by rate of change and derivative functions from the theory of differentiation. It was found that there exists a significant decrease in the trend of demand for maritime labour for LNG carriers over the years covered in the study. The instantaneous rates of change of demand for maritime labour for LNG carrier per annum over the period was not constant as it showed being driven by the significant relationship between the demand for maritime labour for LNG carriers operations and growth in tonnages of seaborne LNG export trade. It was recommended among other things that to stop the current practice where almost half of the vessels serving the shipping needs of the NLNG are owned and management by foreign ship management companies who employ foreign maritime labour; the management of all LNG vessels serving the shipping needs of the NLNG must be handled by NLNG Ship Management Limited (NSML).
Abstract: The study analyzed the maritime labour demand for LNG carriers operations in Nigeria using augmented trend analysis. The objectives of the study among other things were to estimate the demand for maritime labour for LNG carriers operations in Nigeria and to estimate the instantaneous rates of change (IROC) as well as the average rate of change (ARO...
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Load Characterization and Prediction of Entry into Perpetual Construction Domain for Highway Pavement Structures by Truck Factor Study
Mbaezue Nkwute Donatus,
Chukwuedozie Chinedu Samuel
Issue:
Volume 6, Issue 2, June 2020
Pages:
52-60
Received:
19 June 2020
Accepted:
4 July 2020
Published:
17 July 2020
Abstract: This paper presents the results of pavement characterization study of a highway by Truck Factor and Axle Load Factor. The study highway is one of Nigeria’s most important corridors linking the South and the North of the country. The Truck Factor obtained is 9.30 Equivalent Standard Axle Loads (ESALs) while the average Load Factor per axle is 3.25 ESALs. These values particularly the Truck Factor are on the very high side in comparison to published figures in other countries. In the United States of America, published figures for Truck Factors for the rural Interstate highway system and rural principal arterials are 0.52and 0.38 respectively. That for the United Kingdom for similar roads is 2.75. Truck axle overload could therefore be one of the sources of prevalent premature pavement failures on this and similar highways in the country. Also, while single axles in the trucks carried a load of 2.29 ESALs each, tandem and tridem axles impacted the pavement with loads of 3.59 and 6.4 ESALs per axle respectively. If the study pavement were to be reconstructed for a design life of 20years, 66.05 million ESALs from truck axles would cumulate in this period as obtained from this study. This figure is more than double the 30million ESALs stipulated as the trigger load for perpetual or long life pavement construction. Therefore, the study highway should be reconstructed as such.
Abstract: This paper presents the results of pavement characterization study of a highway by Truck Factor and Axle Load Factor. The study highway is one of Nigeria’s most important corridors linking the South and the North of the country. The Truck Factor obtained is 9.30 Equivalent Standard Axle Loads (ESALs) while the average Load Factor per axle is 3.25 E...
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