Civil Engineering Journal
Civil Engineering Journal is a multidisciplinary, an open-access, internationally double-blind peer -reviewed journal concerned with all aspects of civil engineering, which include but are not necessarily restricted to:
Building Materials and Structures, Coastal and Harbor Engineering, Constructions Technology, Constructions Management, Road and Bridge Engineering, Renovation of Buildings, Earthquake Engineering, Environmental Engineering, Geotechnical Engineering, Highway Engineering, Hydraulic and Hydraulic Structures, Structural Engineering, Surveying and Geo-Spatial Engineering, Transportation Engineering, Tunnel Engineering, Urban Engineering and Economy, Water Resources Engineering, Urban Drainage.
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IMPROVEMENT OF GEOTECHNICAL PROPERTIES OF COHESIVE SOIL USING CRUSHED CONCRETE
Karkush, Mahdi O.;
Yassin, Sarah
Civil Engineering Journal Vol 5, No 10 (2019): October
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-2019-03091397
Some natural resources such as gravel are not renewable, therefore, it is necessary to reduce the use of such resources and replace them with other recycled, economic, and environmentally friendly materials. Recycled crushed concrete aggregates demolished from old buildings and blocks of waste concrete can be used to replace the natural aggregates. The present study focused on using recycled crushed concrete in improvement the chemical and geotechnical properties of soft soil having undrained shear strength of 6.78 kPa. The soft soil samples were mixed with 5, 10, and 15% of crushed concrete. The blocks of waste concrete are grinded by mills to get crushed concrete which passing sieve no. 4. Such aggregates are lighter than natural aggregates and provide a good deformation modulus when mixed with soil. In Iraq, there are hundred thousand tons of concrete blocks used as fences and now considered wastes after removing these security fences, so it?s important to interest from recycling of such materials to be used in the improvement wide region of soft soils in Iraq. The results of tests showed increasing the undrained shear strength of soft soil by 175-193.5% and reduced the compressibility of soft by 25-31% measured in terms of compression index.
Analysis for Stabilization of Soil Slope in Silty Soil with Replacement of Soil Cement
Muhammad Zohair;
Dildar Ali Mangnejo;
Naeem Mangi
Civil Engineering Journal Vol 5, No 10 (2019): October
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-2019-03091407
The slope instability may result due to change in stress conditions, rise in groundwater and rainfall. Similarly, many slopes that have been stable for many years may suddenly fail due to loss of soil shear strength, and external forces. This is a crucial problem as it may destroy buildings, damage roads, and even leads to loss of human life. So it is imperative to understand failure mechanism and adopt safety measures to prevent such failures. The objective of this study is to analyze the slope at different angles (at 300, 350, 450 & 600 ) in silty soil and propose a method to stabilize it. The proposed methods to stabilize the existing slope are replacing soil-cement (7% by weight) by vertical layering and layering along the slope. Limit equilibrium method was used to analyze the slopes. The existing slopes were likely to be failed because values of minimum FOS was computed less than 1.5. The FOS improved significantly after replacing soil cement by both methods. Among the two methods, it was revealed that the layering along slope method of soil replacement was most economical and easy to be executed at the site.
A Suggestion of a Procedural Method for the Management of Post-War Waste
Aws S. Noaman;
Angham E. Alsaffar
Civil Engineering Journal Vol 5, No 10 (2019): October
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-2019-03091400
The increasing number of disasters (natural or man-made) worldwide has made post-disaster waste management an essential aspect of disaster recovery. This is obvious in Iraq where the Iraqi government faces an important challenge regarding the events of 2014 (ISIS gang conflict) and the accumulation of huge volumes of construction and demolition (C&D) waste resulting from military operations and terrorist destruction. Field surveys by the specialist teams estimated the amount of waste at about 10 million tons in the Nineveh governorate only, much of which comprises potentially useful materials that could be reused or recycled in the reconstruction process. This paper investigates the obstacles to the sustainable management of such waste in the Nineveh governorate. A pilot questionnaire survey of 76 experts working in the waste management sector was carried out to identify the obstacles to the sustainable management of accumulated waste in the Nineveh governorate. Data analysis was carried out using SPSS version 23.0. Based on the identified obstacles, a procedural method of managing post-war waste that accumulated in Iraq has been created. The paper illustrates several conclusions in the strategic, economic, social, and environmental sectors to address identified gaps in sustainable waste management in Iraq. It is hoped that this study’s results will support post-disaster sustainable development goals in Iraq.
Mechanical Behavior of Hybrid Connectors for Rapid-Assembling Steel-Concrete Composite Beams
Lu, Senqiang;
Zhao, Wei;
Han, Puge;
Hang, Zhenyuan
Civil Engineering Journal Vol 5, No 10 (2019): October
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-2019-03091395
In order to achieve a kind of shear connector suitable for rapid-assembling steel-concrete composite beams, a new type of hybrid shear connectors is proposed, in which the concrete slab with prefabricated circular holes and the steel beam with welded studs are installed and positioned, and then epoxy mortar is filled in the prefabricated hole to fix the studs. To study the mechanical behavior of these hybrid connectors, test on 18 push-out specimens with different prefabricated circular holes are carried out. ABAQUS finite element software is adopted to verify the relationship between the numerical simulation and experiment, influences of the epoxy mortar strength and prefabricated circular holes diameter are studied. The results show that filling epoxy mortar in the prefabricated hole is beneficial to improve the stiffness and bearing capacity of the specimen; the change of epoxy mortar strength has a certain impact on the bearing capacity and stiffness of the hybrid connector; In the case of the same strength of the filling material, the size of the prefabricated circular holes diameter directly affects the stiffness and bearing capacity of the shear stud. The shear capacity equations proposed by considering the epoxy mortar strength and prefabricated holes diameter, and it has a wide applicability.
Experimental Study of a Gas Engine-driven Heat Pump System for Space Heating and Cooling
Zhang, Wei;
Yang, Xianzhao;
Wang, Tao;
Peng, Xueyuan;
Wang, Xiaolin
Civil Engineering Journal Vol 5, No 10 (2019): October
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-2019-03091411
In this paper, the performance of a gas engine-driven heat pump (GEHP) was experimentally studied for space heating and cooling. An experimental test facility was developed for this purpose. The effect of key parameters on system performance was investigated under both cooling and heating modes. The results showed that as the engine speed increased from 1400 to 2000 rpm, the cooling and heating capacities increased by 23% and 28.5%, respectively while the GEHP system Primary Energy Ratio (PER) decreased by 13.5% and 11.7% in the cooling and heating modes, respectively. The system PER in the cooling mode was found lower than that in the heating mode. This indicated that heat recovery from the engine cylinder and exhaust gas was very important for improving the GEHP system performance. In the heating mode, the ambient temperature and condenser water flow rate had a large effect on the system heating capacity and PER, and insignificant effect on the gas energy input. In the cooling mode, the chilled water inlet temperature showed a large effect on both cooling capacity and gas energy input while the chilled water flow rate had a large effect on cooling capacity and insignificant effect on the gas energy input.
Evaluation of Progressive Collapse Performance in Double layer Diamatic Domes
Javid Rezania;
Peyman Torkzadeh
Civil Engineering Journal Vol 5, No 10 (2019): October
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-2019-03091402
Double-layer spatial domes are one of the most common spatial structures, the stability and progressive collapse of which are of great importance in design, construction and maintenance of such special structures. In this paper considering three loading cases and two types of support conditions, the collapse behaviour of double layer Diamatic dome has been investigated utilizing non-linear static analysis and alternate path method usage. In order to modelling compressive member behaviour, effective buckling modes have been obtained by eigenvalue buckling analysis for all of the members. Behaviour of compressive members has been obtained via definition of initial imperfection and non-linear static analysis. Riks arc-length method has been utilized for non-linear static analysis. The numerical results have indicated that reducing the number of the supports and focusing of load in a local area of the dome extremely impact on its vulnerability to failure, as in similar loading condition, decreasing the number of the supports reduces the capacity of damage resistance in spatial domes up to 50 percent. Investigating some models has shown that removing the critical members of the top layer has little effect on load-bearing capacity of the dome and it causes a slight failure in the structure. In this condition, structural redundancy can be considered equal to static indeterminacy. Load bearing capacity of the structure decreased up to 39 percent when compressive members of the web and bottom layers were removed. In this condition, the structure failure is considered moderate.
Compression Splices of Reinforcing Bars in Reactive Powder Concrete
Hussein Al-Quraishi;
Mahdi Al-Farttoosi;
Raad Abdulkhudhur
Civil Engineering Journal Vol 5, No 10 (2019): October
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-2019-03091406
Compression splices are widely used in compression members such as columns in multi- story buildings. There are efficient design equations for compression splice of reinforcement embedded in conventional concrete proposed by design codes of practice. However, there is no design equation for compression splice in compression members made of reactive powder concrete (RPC). So, it is required to introduce a design equation to calculate the steel bars lap splice length of RPC compression members. In this study, an experimental work was conducted to investigate the effect of different variables on compression splices strength. These variables were compressive strength of concrete, transverse reinforcement amount, splice length, yield stress of reinforcement and spliced rebar diameter. The experimental results showed that; Increase in the yield stress of reinforcing bars, length of spliced bars and compressive strength of concrete result in increasing in splice strength. Meanwhile, increase in diameter of reinforcing bars result in decreasing in compression splice strength. The increase in the amount of transverse reinforcement has insignificant effect on compression spliced strength of rebar. Finite element analysis was used to analyze the tested specimens and compared between numerical and experimental result was carried out. The numerical and experimental ultimate load and load-deflection behavior is very close to each other. Finite element method was used to investigate a wide range of experimental variables values through a parametric analysis. A new proposing equation for compression splicing of rebar in RPC column is presented in this research.