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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The Performance of Self-Compacted High Strength Concrete Columns with Laced Steel Section
Majeet, Anas Hameed;
Alshimmeri, Ahmad Jabbar Hussain
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091185
In view of the great orientation to the steel buildings and the large role played by the columns in carrying and transferring the loads it is necessary to go to strengthen the steel rolled columns to meet the requirements of the architecture that witch is looking for large spacing. In present paper this research the objectives of this research can be summarized as following: prevent local buckling occurs in columns, strengthen the steel columns from the weak axis in a new methodology, to compare buckling loads of single lacing reinforcement versus double lacing reinforcement and obtain a high bearing column steel section with small surface area increase in column strength capacity. Different parameters are taking into account to investigate the behavior and strength of steel and composite columns such as slenderness ratio, and double lacings and presence of longitudinal reinforcement that parallel to the column height. The type of concrete that adopt is self-compact concrete with high compressive strength. The new and alternative method is were used to strengthen the steel rolled columns at low cost by strengthening the weak axis to preventing or minimize buckling of the columns by using high strength concrete self-compacted without main reinforcements with steel section columns reinforced by lacing as single and double so that it work as full composite structural element and there are connections between concrete block and steel column. There are five specimens with the same height of 1450 mm that was classified as the control specimen and the others with different parameters such as lacing configurations, presence of longitudinal dowels and presence of concrete subject to concentric load. All specimens except the control filled with self-compacted high strength concrete. The result showed that as increase in strength in presence of concrete as compared with the control specimen. Control specimen gave strength capacity compared with the others composite specimens; the increased are 50% composite column, 62.50% composite column with single lacing and 75.00% composite column with double lacing respectively. Specimen (CL1CDL2R) increased in strength capacity as compared with the control specimen 87.50% and 7.14% compared with specimen (CL1CDL) because of presence dowels along the specimen height that increase the stiffness of the composite column. Presence of single and double lacing reduced the buckling value because of reduced the effective columns height. Specimen (CC1L1) gave maximum buckling 32.00 mm compared with the others specimens such as CL1C), (CL1CSL), (CL1CDL) and (CL1CDL2R) respectively, there is significant difference in buckling that reduced by 17.19%, 28.13%, 45.31% and 55.63% respectively.
Evaluation of the Performance of Reinforced Red Coffee Soils Embankments Subject to Rainfall Event
Salim Ali Zimbu;
Joseph Thuo;
Nathaniel Ambassah
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091180
Infrastructure development in Kenya has led to the need for alternative material in slopes and embankments construction. Sourcing of recommended cohesionless material often leads to the destruction of the environmental features such as rivers and involves high extraction and transportation costs. The need for alternative material is the motivation behind this study. The study aims to evaluate the potential of Red coffee soils of Kenya as a backfill material in the construction of slopes and embankments. Provision of sand cushion layers to sandwich non-woven geotextile material has been suggested to overcome the water drainage and stability problems that have been associated with these soils. The study first involved identifying the properties of both the Red coffee soils (RCS) and the river sand that is to aid in drainage. Numerical model SEEP/W was used in evaluating the effect of geotextile inclination on the performance of RCS embankments before the effect of introducing sand cushions of different thickness evaluated. The numerical results revealed that the stability of reinforced RCS decreased with increase in pore water pressure in the embankments due to rainfall infiltration. Provision of sand cushion layers helped improve both the local and global stabilities of the RCS subjected to rainfall infiltration. The results showed that 150mm sand cushion layer was adequate to improve the performance of RCS embankments and reduced the sand consumption in the construction of embankments to 15%.
Investigation of Strength Parameters of PVA Fiber-Reinforced Fly Ash-Soil Mixtures in Large-Scale Direct Shear Apparatus
Gohari Lasaki, Ashkan;
Jamshidi Chenari, Reza;
Shamsi Sosahab, Javad;
Jafarian, Yaser
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091186
Soil reinforcement is an old and still efficient technique in improving soil strength and stiffness properties. Current paper aims at quantifying the effects of different inclusions on mechanical behavior of fiber-reinforced cemented soil. An experimental program was conducted to study simultaneous effects of randomly oriented fiber inclusions and cement stabilization on the geotechnical characteristics of fly ash-soil mixtures. Chamkhaleh sand, polyvinyl alcohol (PVA) fiber, cement and fly ash with some water were mixed and compacted into large scale direct shear apparatus with three equal layers. PVA fibers were randomly distributed in three compacted layers at predetermined weight contents. Direct shear tests were carried out on fly ash-soil specimens prepared with different cement, fly ash and polyvinyl alcohol contents, and 7 different curing periods. Results show that cement increases the strength of the raw fly ash-soil specimens. The fiber inclusion further increases the strength of the cemented and uncemented soil specimens and transforms their brittle behavior to ductile behavior. The fiber reinforcement and distribution throughout the entire specimen results in a significant increase in the strength of fly ash -soil- cement mixtures.
Strength and Serviceability of Reinforced Concrete Deep Beams with Large Web Openings Created in Shear Spans
Jasim, Waleed A.;
Allawi, Abbas Abdulmajeed;
Oukaili, Nazar K.
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091181
Deep beams are used in wide construction fields such as water tanks, foundations, and girders in multi-story buildings to provide certain areas free of columns. In practice it is quite often occurring to create web opening in deep beams to supply convenient passage of ventilation ducts, cable channels, gas and water pipes. Experimental studies of ten 10 deep beams were carried out, where two of them are control specimens without openings and eight with large web openings in the shear spans. The variables that have been adopted are the ratio of the shear span to the overall depth of the member cross-section, location and dimensions of the opening. Test results showed that there was a decrease in the load carrying capacity of deep beams with openings compared to the control deep beams. This reduction may reach 66% in particular cases. It is clear that, the position of opening in shear span has less effect on the performance of structural concrete deep beams at different serviceability stages. Only 11% increase in load capacity at failure was observed in specimens with openings adjacent to the interior edges of shear spans in comparison with specimens with openings at the center of shear span because the discontinuity of the load path is less. Also the midspan deflection at service load level of the reference beam in specimens with openings adjacent to interior edge of shear spans was less than the midspan deflection of reference specimens by 10% - 33%. Evaluating all these advantages facilitates to recommend, if it is very required, the creation of openings at the interior edges of shear spans of the structural concrete deep beams.
Rock Failure Analysis under Dynamic Loading Based on a Micromechanical Damage Model
Ahmadi, Mohammad Hosein;
Molladavoodi, Hamed
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091199
A micromechanical constitutive damage model accounting for micro-crack interactions was developed for brittle failure of rock materials under compressive dynamic loading. The proposed model incorporates pre-existing flaws and micro-cracks that have same size with specific orientation. Frictional sliding on micro-cracks leading to inelastic deformation is very influential mechanism resulting in damage occurrence due to nucleation of wing-crack from both sides of pre-existing micro-cracks. Several homogenization schemes including dilute, Mori-Tanaka, self-consistence, Ponte-Castandea & Willis are usually implemented for up-scaling of micro-cracks interactions. In this study the Self-Consistent homogenization Scheme (SCS) was used in the developed damage model in which each micro-crack inside the elliptical inclusion surrounded by homogenized matrix experiences a stress field different from that acts on isolated cracks. Therefore, the difference between global stresses acting on rock material and local stresses experienced by micro-crack inside inclusion yields stress intensity factor (SIF) at the cracks tips which are utilized in the formulation of the dynamic crack growth criterion. Also the damage parameter was defined in term of crack density parameter. The developed model was programmed and used as a separate and new constitutive model in the commercial finite difference software (FLAC). The dynamic uniaxial compressive strength test of a brittle rock was simulated numerically and the simulated stress-strain curves under different imposed strain rates were compared each other. The analysis results show a very good strain rate dependency especially in peak and post-elastic region. The proposed model predicts a macroscopic stress-strain relation and a peak stress (compressive strength) with an associated transition strain rate beyond which the compressive strength of the material becomes highly strain rate sensitive. Also the damage growth process was studied by using the proposed micromechanical damage model and scale law was plotted to distinguish the dynamic and quasi-dynamic loading boundary. Results also show that as the applied strain rate increases, the simulated peak strength increases and the damage evolution becomes slower with strain increment.
Analytical Assessment of Bending Ductility in FRP Strengthened RHSC Beams
Ebrahimpour Komleh, Houman;
Maghsoudi, Ali Akbar
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091194
Over the past few years, a wide use of externally-bonded fiber-reinforced polymer composites (EB-FRP), for rehabilitation, strengthening and repair of existing/deteriorated reinforced/prestressed-concrete (RC/PC) structures has been observed. This paper presents a nonlinear iterative analytical approach conducted to investigate the effects of concrete strength, steel-reinforcement ratio and externally-reinforcement (FRP) stiffness on the flexural behavior and the curvature ductility index of the FRP-strengthened reinforced high-strength concrete (RHSC) beams. Analysis results using the proposed technique have shown very good agreement with the experimental data of FRP-strengthened/non-strengthened RHSC beams, regarding moment–curvature response, ultimate moment and failure mode. Also, a newly prediction equation for the curvature ductility index of FRP strengthened RHSC beams has been developed and verified. Then, converting equation of the curvature ductility index to energy one is proposed. Results indicate that the proposed predictions for the curvature and energy ductility indices are accurate to within 1.87% and 3.03% error for practical applications, respectively. Finally, limit values for these bending ductility indices, based on different design codes’ criterion, are assessed and discussed.
A Framework to Predict Time and Cost Risks based on Project Factors
Mohamad Hadi Jalili;
Martin Skitmore
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091195
The occurrence and severity of risks are directly associated with the project factors, and in the case of determining a logical and significant correlation between project factors and risks, the final conditions of the project based on the initial and definite project factors can be predicted. In this research, a final list of 112 risks was prepared using the views of experts. Then, the risks’ weight was determined based on their impact on time and cost and according to the repetition of each risk in the earlier studies, as well as the use of 630industry experts using online web-based forms. Afterwards, 21 project factors that could affect the probability of occurrence and severity of risks related to time and cost were identified, and these factors were prioritized for each risk using the views of 25 experts. Then, applying the Pareto Principle, 14 project factors were identified. In all 4cases, including calculating the weight of risks in the technical literature as well as the experts’ views by time and cost, 14 selected factors were the same, but the weight and effects were different. The results indicate that considering these factors, the risks of time and cost increase from the initial estimate can be accurately predicted.
The Effect of Soil Reinforcement on the Stress and Strain Field Around Underground Square-Shaped Areas and its Internal Lining Efforts in Urban Areas
Alireza Darvishpour;
Asadollah Ranjbar;
Amirmohammad Amiri
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091196
The passage of underground structures from the bottom of the structures on the ground causes a change in the stresses and strains created in the structure as well as the soil environment surrounding the tunnel due to the existence of an interaction between these two sides. In this way, the existence of the surface structure leads to a change in the strain and stress conditions around the tunnel, and in contrast, the tunnel also leads to a change in the stress and settlement around the structures. Therefore, such a reciprocal behavior is very important. In this research, with the help of Abaqus finite element software, two main possible conditions are considered: the creation of an underground structure in the presence of the superstructure, as well as the reverse state of the concept of constructing a building in the state in which the underground structure already exists. One of the subjects studied in this research is the physical modelling effect of the structure, rather than the effect of its wide load on the ground. Other parameters considered in this research are the number of story, the depth of the tunnel, the width of the tunnel, the thickness of the lining, the effect of changes in the soil parameters in the depth and the horizontal distance of the tunnel center from the building center. The results of this research are validated based on the results obtained by other researchers. According to the results obtained in this research, by the increase of the distance between the tunnel center and structure center and depending on the stiffness of the tunnel lining, significant asymmetric stresses are created in the superstructure. The construction of the structure before and after the tunnel construction can affect the unsymmetrical settlement of the structure The stress and strain created in the lining of the tunnel and the surrounding area are also different due to the amount of mobilized force in the reinforcements.
Assessment of Al-Sabtea Bridge under the Effects of Static Loadings
Ali Laftah Abbas;
Qassim Yehya Hamood
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091191
The behavior and strength of composite for composite bridges relay on the connectors that used to connect the steel beams or girders with reinforced concrete deck slab. Different type of shear connectors that available in the market such as headed stud or steel channels are commonly welded to the top face of the steel section to prevent slip at the interface between the two different materials. In present paper, existing composite bridge built in Iraq is modeled using finite elements approach by ANSYS. The bridge is simulate by adopt real dimensions and geometry to check out the performance of connectors and strengths of composite girder under worst static loading conditions proposed by general Iraqi Standard Specification for Road and Bridges such as track, knife and military loadings. The analysis results indicate that the three types applied loading show that all stresses within the acceptable limits and did not reach high values compared capacities of these materials according to the AASHTO ASD code. The maximum stress at bottom face of steel girder is 114.7 MPa and the maximum deflection is 59 mm these values within limits of code.
Design Methodology of Base Plates with Column Eccentricity in Two Directions under Bidirectional Moment
Ebadi, Parviz;
Soleimani, Mohammad;
Beheshti, Mohsen
Civil Engineering Journal Vol 4, No 11 (2018): November
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091197
Base plate is a critical structural component responsible for transferring loads from the structure to the foundation. By increasing the contact surface between the column foot and the foundation, base plates contribute to more manageable distribution of column forces and the resulting stresses in the substructure. The off-center positioning of column on the base plate, which is sometimes unavoidable because of the limitations imposed by elevator shaft, adjacent buildings, etc. could be a major design issue. This paper investigates the effects of column eccentricity on the design and stress distribution of base plates and the impact of stiffeners on the thickness of these plates. In this investigation, a comparison is made between the superposition method and the finite element method in terms of their evaluation of stress levels under the base plate with column eccentricity. The study also aims to determine the magnitude and distribution of maximum stresses with plateâs thickness and dimensions and columnâs position on the plate taken into account. The results show that the superposition method can be confidently used in the force analysis and design of base plates with column eccentricity under bidirectional moments.