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Comparative Analysis of the Compaction of Natural Offshore Sand and Cement Stabilized Offshore Sand for Road Construction
Issue:
Volume 6, Issue 2, April 2021
Pages:
21-27
Received:
18 February 2021
Accepted:
3 March 2021
Published:
12 March 2021
Abstract: This research concerned itself with the comparative analysis of compaction of natural offshore sand and cement stabilized offshore sand for road construction in swampy regions. Sieve analysis and compaction (moisture-density relationship) tests were conducted on the offshore sand sample to compare the compaction efforts of the two materials for road subbase filling. Based on the results of the tests carried out, the offshore sand sample was found to belong to the A-2 group and falls within Grading Zone 2. The results of dry density against cement content as well as optimum moisture content against cement content shows that compaction of the offshore sand is poor with values of maximum dry density and optimum moisture content obtained as 1.755g/cm3 and 11.67% respectively. After 4% Cement Content stabilization, the values increased to 1.935g/cm3 and 12.21% respectively. At 6% Cement Content stabilization, the value of Maximum Dry Density increased to 1.948g/cm3 while the Optimum Moisture Content dropped to 8.77%. At 8% cement content stabilization, the values obtained were 1.967g/cm3 for maximum dry density and 10.40% for optimum moisture content. At 10% cement content, the results were 1.982g/cm3 for maximum dry density and 12.25% for optimum moisture content. Upon increasing cement content to 12%, the values obtained became 2.027g/cm3 for maximum dry density and 9.76% for optimum moisture content. It follows therefore that increasing cement contents yielded increase in compaction of the offshore sand sample. This investigation concludes that cement can be used to stabilize offshore sand to improve its engineering property of compaction for use as subbase material for construction of road in swampy regions.
Abstract: This research concerned itself with the comparative analysis of compaction of natural offshore sand and cement stabilized offshore sand for road construction in swampy regions. Sieve analysis and compaction (moisture-density relationship) tests were conducted on the offshore sand sample to compare the compaction efforts of the two materials for roa...
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Bridge Safety Dangers-Fatigue Cracks, Brittle Failures and Grit Blasting
Issue:
Volume 6, Issue 2, April 2021
Pages:
28-45
Received:
24 February 2021
Accepted:
12 March 2021
Published:
22 March 2021
Abstract: Fatigue failures in bridges have been extensively studied for decades, and experimental data was applied to create fatigue curves to be used for bridge designs, however, new research questions the validity of these curves with respect to safe bridge design. Specifically, grit blasting for coating adherence creates surface damage in the form of sharp indentations and peaks over entire steel surfaces. These imperfections act as stress raisers that accelerate bridge failures by reducing the number of cycles to failure and the stresses required to cause failure. Strong differences of opinion exist with respect to this complex issue. This author believes that there is a significant threat to bridge safety, while other authors believe that there is no safety threat at all. The goal of this article is to effectively refute opinions which claim that bridge safety is adequate. To do so, a thorough review of earlier publications is combined with new developments on grit blasting fatigue. Bridge safety is questionable since bridge design requirements in the form of fatigue curves are questionable. There is limited information, one way or the other, to prove the full extent of grit blasting effects on steel bridge fatigue failures, and this paper fosters an understanding of this dangerous threat. Available results clearly prove that bridge fatigue properties are reduced by grit blasting, which in turn reduces the safety of design practices for bridges. An open and unknown question exists, what is the complete extent of grit blasting effects on large structures? That is, bridge failure mechanisms are not fully understood, there are uncertain risks with respect to bridge fatigue damages, and a paramount risk concerns grit blasting. Grit blasting safety effects cannot be dismissed. Moreover, evolving facts prove that the inherent dangers in bridge design practices must be addressed and resolved. Specifically, bridge design curves account for repeated loads on bridges caused by traffic, and further research is mandatory to determine the safety errors inherent in these curves, which are shown to be inadequate by this innovative research. A resistance to new ideas serves as an unacceptable reason to curtail technology that will improve bridge safety.
Abstract: Fatigue failures in bridges have been extensively studied for decades, and experimental data was applied to create fatigue curves to be used for bridge designs, however, new research questions the validity of these curves with respect to safe bridge design. Specifically, grit blasting for coating adherence creates surface damage in the form of shar...
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Strengthening Strategy of Old Bridge in Indonesia (Tukad Yeh Bakung) by Using Optimization and Preservation Approach
I Nyoman Sutarja,
I Gede Adi Susila,
Made Ari Ariarsha Sumekar
Issue:
Volume 6, Issue 2, April 2021
Pages:
46-53
Received:
9 February 2021
Accepted:
8 March 2021
Published:
26 March 2021
Abstract: A reliable, integrated and sustainable highway road network system throughout the national territory needs to include an upgraded structural capacity of bridges; particularly Tukad Yeh Bakung bridge in Bali-Indonesia. It was essentially needed to improve transportation services to provide direct impacts of economic growth and social welfare locally. To upgrade structural capacity an old bridge has been done by applying a preservation method sustainably: maintenance and rehabilitation in order to keep the bridges provide services properly. This preservation method has also been intended to provide an acceptance and functional criteria (certification of life services) of bridge 50 up to 100 year, and further. An old bridge (Tukad Yeh Bakung) was built in 1977 located along the national road network between Denpasar and Gilimanuk with reference (stationing of km 54+400). The bridge was suffered with structural damages due to exceeded load services, earthquakes, and material degradation. The damages of bent was essentially needed to be preserved since the damages found such as cracked and porous on concrete deck/slab and exposed of slab/bending reinforcement which clearly hazard from corrosions as well as decreasing its capacity. Simple bridge preservation has been done by giving additional or replacement of flexural reinforcement as well as a confinement method for the concrete column. Ultimate capacity ratio (Mu/φMn) of bent has been evaluated and typical confinement method will also increase lateral load capacity of the pier and prevents of collapse (due to local and global/longitudinal buckling).
Abstract: A reliable, integrated and sustainable highway road network system throughout the national territory needs to include an upgraded structural capacity of bridges; particularly Tukad Yeh Bakung bridge in Bali-Indonesia. It was essentially needed to improve transportation services to provide direct impacts of economic growth and social welfare locally...
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Analysis on Disease State of Urban Operational Subway Tunnels
Fei Dong,
Jun Huang,
Ao Li,
Caichi Gao
Issue:
Volume 6, Issue 2, April 2021
Pages:
54-62
Received:
19 March 2021
Accepted:
29 March 2021
Published:
7 April 2021
Abstract: Structure form, steel bar and service time were considered to be the main factors of the tunnel disease state, based on the disease inspection results of subway tunnels in Beijing. The conclusion indicated that the diseases of shield tunnel such as ovalization of tunnel cross section, lining cracks, crushing and dislocation of duct pieces and water leakage were caused by the deformation of segment joints. Lining crack was the main disease form in monolithic tunnel. The width and depth of cracks were greatly influenced by tunnel operation time and had the characteristics of discreteness and random. Steel bar used in concrete lining could significantly enhance safety of tunnel structures. Water leakage in subway tunnel was influenced by rainfall and usually could be observed at the gaps of tunnel structures, such as bolt holes and segment joint of shield tunnel or the construction joints, deformation joints and lining cracks of monolithic tunnel. The most lining cavities were found located at the vault and the cavity shape was similar to strip, square or oval with lining cracking nearby. The carbonation depth of lining concrete was proportional to tunnel operation time and its value and speed at ballast bed was most, sidewall less and vault least. It is hoped that the results can provide some reference for the disease law analysis and treatment of urban tunnel.
Abstract: Structure form, steel bar and service time were considered to be the main factors of the tunnel disease state, based on the disease inspection results of subway tunnels in Beijing. The conclusion indicated that the diseases of shield tunnel such as ovalization of tunnel cross section, lining cracks, crushing and dislocation of duct pieces and water...
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Engineering Properties of Nagar Parkar Plutonic & Volcanic Rocks as a Construction Aggregates, District Tharparkar, Sindh Province Pakistan
Mushtaque Ahmed Pathan,
Maryam Maira Pathan
Issue:
Volume 6, Issue 2, April 2021
Pages:
63-68
Received:
11 May 2020
Accepted:
26 March 2021
Published:
13 April 2021
Abstract: The purpose of this paper is to study the important engineering properties of the volcanic rocks present with the Nagar Parkar Granites located from Sindh University Campus Jamshoro 5 h 44 min (355.3 km) via Hyderabad - Badin Road and 5 h 57 min (323.5 km) via Naukot - Mithi Road and Islamkot, the rocks look suitable for pavement and concrete aggregates. Number of standard tests were conductedted. Which included; Specific Gravity, Gradation, Soundness, Particle shape and Surface Texture Absorption Index, Abrasion Resistance, Deleterious Materials,, in addition to moisture content and Fineness modulus. Geologically there are two main components known as Pink Granites and Grey granites on the basis of the plagioclase / orthoclase mineral component. Results of the standard tests depicted that both Pink Granites and Grey Granites samples have different characteristics especially concerning abrasion resistance. After comparing the obtained results with standard specifications showed that both samples can produce aggregates that are suitable for pavement but only Pink sample can produce concrete aggregates. It was also assumed that there should be a technical control in the crushing circuit to produce the required gradation.
Abstract: The purpose of this paper is to study the important engineering properties of the volcanic rocks present with the Nagar Parkar Granites located from Sindh University Campus Jamshoro 5 h 44 min (355.3 km) via Hyderabad - Badin Road and 5 h 57 min (323.5 km) via Naukot - Mithi Road and Islamkot, the rocks look suitable for pavement and concrete aggre...
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Effect of Different Material Schemes on Carbon Emissions in Construction Material Production Stage
Yang Hu,
Bin Dai,
Jianhong Wu,
Yinan Wu,
Jing Yuan
Issue:
Volume 6, Issue 2, April 2021
Pages:
69-76
Received:
9 March 2021
Accepted:
30 March 2021
Published:
13 April 2021
Abstract: Introduction: Building energy consumption accounts for a large proportion of global energy consumption, and it is urgent to reduce building carbon emissions. There are many different components in the Building, each of which produces a somewhat different amount of carbon emissions, such as column, beam, floor, exterior wall and interior wall. This Paper is focusing on looking for the components’ differences in carbon emission in order to provide some valuable advises in choosing building materials. Methods: Using the building information model, the sample building is divided into five parts: column, beam, floor, exterior wall and interior wall. Firstly, the quantities of each part of the building is calculated from building information model. Secondly, the method of permutation and combination is performed by choosing different materials including concrete, steel, wood, brick and glass, and then forming 14 schemes. Finally, carbon emissions at production stages are calculated of all 14 schemes by known carbon emission factors. Conclusion: The average proportion of each part of carbon emissions is obtained both with the carbon emissions from different materials. Choosing the lowest and highest theoretical scheme in order to analysis the influence of different materials on carbon emissions in construction production stage, so that the effective data reference for building energy saving and emission reduction can be concluded.
Abstract: Introduction: Building energy consumption accounts for a large proportion of global energy consumption, and it is urgent to reduce building carbon emissions. There are many different components in the Building, each of which produces a somewhat different amount of carbon emissions, such as column, beam, floor, exterior wall and interior wall. This ...
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Assessment of Quality Management Practices of Building Construction Firms in Uganda: A Case of Kamwenge District
Muhwezi Lawrence,
Baguma Andrew,
Mubiru Joel
Issue:
Volume 6, Issue 2, April 2021
Pages:
77-86
Received:
15 February 2021
Accepted:
26 March 2021
Published:
20 April 2021
Abstract: Quality management in the construction industry includes quality control, quality planning and quality assurance to improve the quality of buildings. However, there have been challenges related to cost variations, timeliness and delays in maintenance which affect quality management of buildings. The study assessed quality management practices of building construction firms in Uganda with the purpose of developing a framework that can be used by construction firms to improve on the quality of buildings. In this study, descriptive design was employed in which both qualitative and quantitative data were collected from a sample size of 54 respondents purposively selected from employees of construction firms and Kamwenge local government using a survey questionnaire and documentary reviews. Data were analyzed using descriptive and multivariate analysis in SPSS version 25. The contribution of each of the factors on the quality of construction firms was determined by use of Relative Importance Index (RII) and the ranking of these attributes in terms of their criticality as perceived by the respondents. The findings indicated that procurement systems, third party certification and on site supervision greatly influenced the cost, timeliness and delivery of buildings hence affecting the quality management practices. The developed framework shall be used to engage stakeholders in the phases of the construction projects mainly buildings to improve on cost estimation and timely completion hence improving on quality management of buildings and service delivery.
Abstract: Quality management in the construction industry includes quality control, quality planning and quality assurance to improve the quality of buildings. However, there have been challenges related to cost variations, timeliness and delays in maintenance which affect quality management of buildings. The study assessed quality management practices of bu...
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