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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Improving Flexural Behavior of Textile Reinforced Concrete One Way Slab by Removing Weft Yarns with Different Percentages
Omar Hamid Hussien;
Amer M. Ibrahim;
Suhad M. Abd
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091207
Textile reinforced concrete that developed at recent years is composed of the continuous textile fabric incorporated into the cementitious matrix. The geometry of the textile reinforcements has a great influence on the TRC overall behavior since it affects the bond efficiency perfectly. The effect of weft yarns removing on the flexural behavior of (1500 × 500 × 50) mm one way slabs was investigated, eight layers of the carbon fabric were used with (50%, 67% and 75%) removing of weft yarns in addition to one specimen without removing. The four one- way slabs were casted by hand lay-up method, cured for (28) days and tested in flexure using four points method. The bending capacity and the bond efficiency factor were calculated according to the conditions of the equilibrium models by comparing with experimental results. The results revealed that with higher removing proportion there was a perfect improvement in the flexural capacity, higher first crack load, eminent post cracking stiffness, higher average concrete strain and lower ultimate mid span deflection and higher toughness and ductility. Furthermore, the results clarified that there is an optimum percent of weft yarns removing at which the damage occurrence around the weft yarns is significantly reduced, and this negative effect constriction overcome the positive anchoring effect.
Studying Non-coaxiality in Non-lane-based Car-following Behavior
Ramezani Khansari, Ehsan;
Tabibi, Masoud;
Moghadas Nejad, Fereidoon
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091202
In this paper, in order to study non-lane-based car-following, the non-coaxiality concept is defined, where there is a significant lateral difference between the leader and follower vehicle. Two main reasons for non-coaxiality were addressed by drivers in the interview: providing more visible distances beyond leader vehicle and increasing the possibility of escaping in sudden brakes to avoid rear-end collision. Results showed that non-lane-based behavior was due to the effect of the existence of other cars in the traffic flow. By reducing speed or increasing density, vehicles more affect each other. But this trend will continue up until vehicles fill the free spaces. In other words, vehicles make others stick to the leader’s path in high-density flow. Studying the relationship between lateral distance and time headway demonstrated that time headway threshold for initiation of car-following behavior in Iranian drivers can be approximately 2 seconds. In this study, Overtaking was defined as a part or continuation of the non-lane-based driving behavior. For overtaking on the left, steering angle, the final lateral distance and the lateral speed difference between the follower and leader were 33%, 28% and 15% less than overtaking on the right.
Development of Closed-Circuit Elastic Mounting for Working Bodies in the Interrow Cultivator
Kudzaev, Anatoly Beshtauovich;
Korobeinik, Ivan Anatolyevich;
Tsgoev, Alan Elbrusovich;
Tsgoev, David Valeryanovich;
Kalagova, Rita Vladimirovna;
Urtaev, Taimuraz Aslanbekovich
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091218
The main drawbacks of cultivators intended for the tillage of stony soils are low reliability of the working bodies, high draught resistance and inability to maintain the required depth of tillage. Hence, the scientists in the Gorsky State Agrarian University conducted a range of studies and trials that allowed them to improve the design. The aim of the present study was to develop a new design of the closed-circuit elastic suspension for the working bodies of a cultivator that is intended for the performance on stony soils and provides high reliability, low draught resistance of the working bodies (in comparison with the existing models), and the required depth of tillage. The tests of the proposed design were performed in the laboratory conditions on a specially designed and constructed stand equipped with tensometric devices. Horizontal and vertical stiffness of the suspension and its frequency was studied. The field trials were performed by a specially constructed machine that was mounted on a tractor. The machine was equipped with tensometric gauges that were reading the sensors with the frequency of 1000 times per second. All the primary data were processed by the respective methods of mathematical statistics. The authors identified the effective model of the closed-circuit elastic suspension for the central working body with the radius of bows R1=125mm, R2=135mm, horizontal stiffness Сhor=25.6 N/mm and natural vibration frequency ν ϵ [10.2…16.2] Hz. A closed-circuit bow type suspension with the stiffness Сhor=18.34 N/mm and natural vibration frequency ν ϵ [8.5…8.7] were most suitable for the side working bodies of a cultivator. It was established that in comparison with the traditional mounting of working bodies, the designed elastic suspension of the working bodies provided the reduction of the draught resistance by 3.7…15%, high reliability and uniform required depth of tillage.
Influence of Reduced Water Cement Ratio on Behaviour of Concrete Having Plastic Aggregate
Tayyab, Saad;
Ullah, Asad;
Shah, Kamal;
Mehmood, Faial;
Gul, Akhtar
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091213
The production and use of plastic bottles is increasing tremendously with passing time. These plastic bottles become a problem when they are disposed as they are non-biodegradable. This means that the waste plastic, when dumped, does not decompose naturally and stays in the environment affecting the ecological system. The use of alternative aggregates like Plastic Coarse Aggregate (PCA) is a natural step in solving part of reduction of natural aggregates as well as to solve the issue discussed above. The researchers are trying from half a century to investigate the alternative materials to be replaced in concrete mixture in place of either aggregate or cement. In this research, the concrete made from plastic waste as coarse aggregates were investigated for compressive strength and Stress-strain relationship. Plastic coarse aggregate have been replaced in place of natural coarse aggregate by different percentages with w/c 0.5, 0.4 and 0.3. The percentage replacement of plastic aggregate in place of mineral coarse aggregate was 25%, 30%, 35% and 40 %. Using Super-plasticizer Chemrite 520-BAS. OPC-53 grade cement was used. Total of forty five Cylinders were prepared based on different combination of Percentage of Plastic aggregate replaced and W/C as discussed above and checked for compressive strength and stress-strain relationship. The compressive strength increases by about 19.25% due to the decrease in W/C from 0.5 to 0.3 for plastic percentage addition of 40%.
Effectiveness of Locally Available Superplasticizers on the Workability and Strength of Concrete
Ashfaque Ahmed Jhatial;
Samiullah Sohu;
Muhammad Tahir Lakhiar;
Jam Shahzaib;
Ahsan Ali Buriro
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091208
Though superplasticizers (SP) are well-known chemical admixtures which are added into concrete to enhance the workability and achieve higher strength while reducing the water content. But the rapid increase in different SP in Pakistan has created confusion on the effectiveness of SP. This experimental study was carried out to study the effect of locally available SP on the workability and compressive strength of M15 grade concrete. Three different SP were utilized, with dosage ranging from 0.5% to 2.5% with an increment of 0.5%. The water-cement ratio remained constant at 0.5 for all samples. Based upon the results, all three SP increased the workability as well as strength of concrete. The optimum dosage was determined to be 1.5% to 2.00% for all three SPs used in this research work. BASF 561 was determined to be more effective, as it achieved the maximum workability as well as compressive and flexural strengths.
Study on Seismic Dynamic Response of Shallow-Buried Subway Station Structure and Ancillary Facilities
Peng, Miao;
Cui, Wei Jian
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091203
Strong earthquakes can cause damages to structural members and also yield non-negligible damages to nonstructural facilities, the latter being closely related to earthquake-induced inertial forces. At present, the acceleration response regularity of shallow-buried subway station structure is not very clear. Using the finite-element software ABAQUS, a dynamic soil-structure interaction model for a two-story subway station structure is established. The distribution of the peak acceleration response of the structure is obtained, and the damage assessment of non-structural facilities is carried out based on the structural acceleration response. The results demonstrate that, in general, the peak acceleration responses of the subway station structure increase from lower to upper story levels, while the peak acceleration responses at the same height are practically equal. Moreover, the peak accelerations of a shallow-buried subway station structure are generally less than or close to the peak ground acceleration. Furthermore, the nonstructural facilities are slightly damaged when subjected to a peak bedrock input acceleration of 0.1 g, and moderately damaged under a peak bedrock input acceleration in the range 0.2 – 0.6 g. Based on the acceleration response characteristics, it is proposed that the peak surface acceleration can be used as an index to evaluate the damage of non-structural facilities in shallow-buried subway station structure, which is simple, practical and basically meets the precision requirements.
Finding Critical Element in the Progressive Collapse of RC Structures Using Sensitivity Analysis
Farahani, Ahmad;
Kheyroddin, Ali;
Sharbatdar, Mohammad Kazem
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091219
Failure of some elements in the structure can play triggering role for beginning of collapse progression. The critical element is the structural element that when it fails, leads to progressive collapse. To find the critical element of the structure, sensitivity analysis should be done. But there are not specific structural criteria for using in sensitivity analysis. In this paper following GSA, UFC 4-023-03 and ASCE guidelines, sensitivity analysis has been modified and applied to find the critical element of a major number of reinforced concrete structures. 1080 3D nonlinear pushdown analyses were done and the results showed that the place of the critical elements differs in different stories and different plan shapes of high rise structures. In the structures with high aspect ratio in height, the critical element of the whole structure is located in the story of 2/3 height of the structure. When the aspect ratio of the structure in plan increases, sensitivity of the columns in the long dimension of the structure become closer to each other.
Utilizing Modern Experimentation Method to Quantify Jet-Breaker Dimension Effects on Drop Manhole Pool Height
Seyedreza Hasheminejad;
Mohammad-Javad Khanjani;
Gholam-Abbas Barani
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091214
Drop manholes are commonly employed in sewer and drainage systems to reduce pipes slope. The operation of these structures is dominated by their flow regime. Poor hydraulic performance of them under Regime R2 was improved with the jet-breaker, which intersects the inlet jet; yet its proper dimensions were needed to be precisely determined. In this paper, effects of jet-breaker length, width, sagitta, and angle on drop manhole pool free-surface height were experimentally studied under 80% filling ratio of the inlet pipe. The modern statistical Design of Experiment (DoE) methodology and dimensional analysis were utilized to design the experiments in accordance with the 24-1IV fractional factorial design. Consequently, nine specific jet-breakers were built and examined at two different angles, and under various flow rates. The statistical analysis of the results shown that manhole pool height was significantly decreased when jet-breaker length, width, and sagitta were 1, 1.4, and 0.7 times the inlet pipe diameter, respectively, and its angle was at 70°. The use of DoE resulted in 21% reduction in experimental runs, cost, and time, while it provided comprehensive data analysis and objective conclusion.
Seismic Design of Steel Structures with Special Flexural Frame Based on Performance by Durability Method
Pouyan Ashrafzadeh;
Arash Kheyrolahi
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091209
Equivalent static, response spectrum and time history analysis are the well-known analysis methods that traditionally proposed. These methods are highly accurate but requires a great deal of time to match accelerations and the number of analyses, in the other words these methods are time consuming methods. Hence recently the structures are investigated using the durability time method, which plays an essential role in reducing the number of analyses that needs to be created; In fact, the durability time method is a new method of seismic analysis that is presented with a minimum number of time histories analysis. In this method the structure is placed under the influence of an increasing dynamic stimulation, structural response has been investigated over time and evaluated according to the corresponding response to different levels of stimulation intensity, strengths and weaknesses, and structural performance. In this study, steel folding frameworks with 5, 10 and 15 floors were investigated under two analytical methods (Time durability and Time histories methods). At first, the frameworks will be exposed under history of Imperial Governor, Kobe and Lumaprita earthquakes and analysis by finite element software ABAQUS. Then, based on the three analytical functions, the durability is investigated and the results are compared with each other. Finally, the behavior of the structures discussion and conclusion. The results show that the durability analysis method for earthquakes with higher intensity and time is more efficient, and for the Time-less earthquakes by time history method parametrically have a parametrical difference of 5%.
Evaluating the Existing Barriers in Implementing Constructability
Samereh Jadidoleslami;
Ehsan Saghatforoush;
Amirhossein Heravi;
Christopher Preece
Civil Engineering Journal Vol 4, No 12 (2018): December
Publisher : Salehan Institute of Higher Education
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DOI: 10.28991/cej-03091204
In fact, constructability is facilitating the construction of a project through integrating knowledge and experience to achieve the overall and common objectives of the project in all stages of it, but practically there is still a significant gap between design, construction, and achieving the desired project objectives. Studies show that separating the design and construction processes and lack of presence of the contractor in the design stage, prevent the effective use of experiences and specialty of the contractor to improve and develop design processes. This issue results in increasing project time and cost, poor relationships, and also increasing project waste and duplication. The barriers to implementing this concept can have major differences with each other in different locations all over the world, due to the unity of the executive conditions in various countries. This paper evaluates the existing practical barriers to implementation of constructability in the construction industry. A comprehensive literature review has been performed by the authors through using the Meta-Synthesis method and findings were used to form research assumptions. Three case studies of Mass Housing project (MHP) in Tehran were instigated. Outputs taken from nine interviews with different experts in this industry working in diverse areas, including owners, consultants and contractors are then ranked after theoretical saturation compared using the NVIVO Software and through pattern and descriptive analyses. The concept of constructability is focused on the early presence of contractors in the initial stages of the project. So that, through integrating knowledge and experience, problems due to lack of their presence in the early stages of the project can be reduced. Comparing the existing barriers to implementing constructability in Iran with those of the wider world, presents some effective solutions to facilitate the presence of the construction contractors in the early stages of projects.