Civil Engineering Infrastructures Journal
Volume:55 Issue: 2, Dec 2022

Operational and investment costs increase due to aging of the network, increasing the failure rate, leakage and the water demand, new investments and energy consumption. Several methods and tools with different initial investment and operating costs are proposed for reducing water losses in the related literature. The aim of this study is to make detailed evaluations within the framework of economic components for effective and sustainable water loss management and provide a reference for further studies. The most important advantage is that there has not been a detailed assessment and discussion in this context within the framework of economic analysis and the economic leakage level. The methods and tools for reducing the water losses such as district metered areas, passive leakage control, active leakage control, pressure management, pipe management and network renewal methods, were evaluated economically and discussed. The most important issues in water loss management are the definition of the economic leakage level and the cost components that are the maintenance and break repair, methods applied to detect and control the leaks and automation systems for monitoring, control and data transfer. Moreover, the priority, suitability, applicability and economic impact of the methods should be considered to decide the methods for more efficient use of resources.

The engineering properties of stabilized soils are varied for many factors such as soil heterogeneity, soil composition, soil structures, geological conditions, and the difference of interaction between the soil and stabilizers. These variations required the consideration of stabilization at a specific site option. These natural materials, therefore, critically influence the success of a construction project. The reason for this study was to quantify the improvements achieved in the engineering properties of expansive soils due to lime stabilization. This study considered quantitative experimental to determine lime-stabilized expansive clay soil's engineering properties using a laboratory program. Laboratory tests were to determine Atterberg Limits, compaction test, free swell test, California Bearing Ratio (CBR), and pH values of the mixtures. The collected soil samples were stabilized using 2, 4, 5, 6, and 8% of hydrated lime by weight. The optimum lime for the stabilization of expansive soils was 5% using hydrated lime. As percentages of hydrated lime increased, there were improvements in stabilized subgrade soil properties. The more significant upgrade in engineering properties was observed on California Bearing Ratio (CBR), and lower improvements were on maximum dry density. The result indicated that the stabilizer is very effective in improving strength parameters than index parameters. The hydrated lime stabilized soils under the optimum ratio fulfill the standard requirements as subgrade soils.

Faults have large impact on the mechanical behavior of soil in pipeline’s construction. These pipelines have been embedded to supply vital resources such as water, oil, and gas for consumers. To prevent damage, it is highly recommended not to construct pipelines around active faults. However, it is generally inevitable to cross the fault due to wide extension of pipelines. In this paper, a numerical analysis and parametric study on an underground water pipeline in Tehran, Iran, under the fault-induced displacement is presented. It is important to note that the main focus of this study is on elbow components which are the most critical sections in pipeline systems. The effects of crossing angle, distance to elbow and various soil properties on the elbow response are investigated. It is aimed at finding a safe regulation to embed pipelines with the lowest level of risk expected in elbow components after fault movement. The results show that the elbow component does not suffer serious damage when the crossing angle is 90°, provided they are not located in the close vicinity of the fault rupture surface. However, when the crossing angle decreases to 60 and 45 degrees, these components are much more vulnerable.

Waste generated by steel industry cases environmental and economic problems. Therefore, it becomes very important to utilize steel industrial waste material in a proper manner. One promising use for this huge amount of industrial waste is soil improvement. In this work, Unconfined Compressive Strength (UCS) tests were conducted to study the influence of steel slag on the mechanical characteristics of cement-stabilized sand. The UCS tests were conducted on the compacted specimens which prepared in the laboratory at their Optimum Moisture Content (OMC) and modified proctor Maximum Dry Density (MDD). The results indicate that use of steel slag powder as a partial replacement of chemical stabilizer such as cement in soil stabilization has advantages from economic, environmental and technical points of view. The highest value of UCS was observed in the sample containing 7.2% cement and 0.8% steel slag powder. Beyond optimum steel slag powder dosage, the UCS value decreased. The addition of polypropylene fiber into the specimens treated with cement or steel slag powder improves significantly the mechanical behavior of specimens and significantly increases the UCS and strain corresponding to the maximum compressive strength. The specimen containing 0.2% of polypropylene fiber, 6.4% of cement and 1.6% steel slag exhibits the highest UCS value when the sum of the amounts of cement and steel slag was 8%. The failure pattern of specimen indicates a transition from ductile to brittle behavior with addition of cement and steel slag. However, the addition of polypropylene fiber changes the brittle response of treated specimens to a more ductile behavior.

The placement of bracing can affect the seismic response and energy balance in the outrigger braced systems. In this study, it is attempted to investigate the effect of placement optimization of outrigger braced system on the seismic response of a 50-story structure. IDA curves are used to investigate the seismic responses. Sa and Sd are considered as intensity measure (IM) Parameters. Maximum story drift and inelastic strain energy considered as Engineering Demand Parameters (EDP). At first, IDA curves are derived based on maximum story drift in the structures. When the performance level is determined, their fragility curves are derived and compared. In the next step, the energy balance is investigated in the structures and the strain energy parameter is selected as EDP, which the damage level is determined in accordance with. Fragility curves are plotted and the results are assessed using the plastic strain energy. The results show that the placement optimization of outrigger braced system improves all structural parameters and reduces the collapse probability. Moreover, the fragility curves obtained from plastic strain energy as EDP are quite similar to the fragility curve derived from the selection of story drift as EDB.

Road traffic accidents are one of the major issues that have been investigated by many researchers in transportation communities. One of the effective factors in reducing accidents is to improve the surface friction of the road pavements, which is often measured by the skid resistance. The presence of dust would reduce drivers' field of view and also the skid resistance of the road surface, and thereby contributes many road accidents in these areas. In this research, the existing dust particles were collected from the surface of the roads. These fine dust with variable amounts were scattered as contaminants on the surface of asphalt samples and skid resistance was measured for HMA and SMA asphalt samples with different gradations and temperatures. The results showed that dust deposition on the pavement surface in three months causes pavement skid resistance in the two types of HMA and SMA asphalt mixtures, decreasing 9 to 16% in the dry state and 25 to 35% in the wet state. According to the obtained results, it is recommended to apply SMA asphalt with a nominal size of 19 mm as a Topeka layer in the areas that are exposed to fine dust, especially in conditions of high traffic and high ambient temperature.

Masonry buildings are the most utilized structural system worldwide due to the ease of construction and cost-effectiveness. The effective design of masonry structures has been always an important research subject. Experimental studies are the main component of such research studies. The budget and equipment limitations may challenge the laboratory testing of full-scale masonry specimens and test structures. As such, the use of model-scale specimens may be found as a promising alternative to study the response behavior of this type of structure. In this paper, the stress-strain behavior of half-scale concrete masonry units and prisms (hollow and fully grouted) under compressive loads is evaluated and compared with their full-scale counterparts. The half-scale specimens are standard in that the principles of similitude law have been followed precisely in their aggregate grading, mix-design, physical dimensions, and loading. The stress-strain diagram and failure modes of the half-scale are similar to those of the full-scale. The ratio of half-scale to the full-scale compressive strength of the hollow and grouted masonry prisms on average was found to be 1.07, and 1.08, respectively. The experimentally-evaluated response of the standard half-scale specimens that fully satisfy the requirements of similitude law may be extended with good accuracy to the full-scale masonry.

This paper focuses on the design of Adaptive-Neural Interval Type-2 Fuzzy Logic Controller (AN-IT2FLC) in an active tuned mass damper to reduce the response of building under seismic excitation. One of the main shortcomings of Interval Type-2 Fuzzy Logic Controller (IT2FLC) is its need to adjust in any earthquake. This is whilst the AN-IT2FLC can solve this problem using the training process. In this research, four inputs are used for designing and training of AN-IT2FLC as controlled displacement and velocity of roof level with IT2FLC, acceleration of the implemented earthquakes and the control force of IT2FLC. AN-IT2FLC training performed based on the eight earthquake records of El Centro, Hachinohe, Kobe, Northridge, Loma Prieta, Tabas, Morgan Hill and Erizkan with various seismic characteristics. In order to investigate the effectiveness of the proposed controller, an 11-story building with ATMD on its top floor analyzed under another four ground accelerations of Chi-Chi, Kern-county, Coalinga and Coyote-lake records. The results revealed that ATMD with AN-IT2FLC is able to achieve more response reduction with higher speed and accuracy rather than that of the IT2FLC.

Deterioration due to corrosion is an important issue affecting the durability, strength, and sustainability of buildings and structures. Many cities are located in coastal areas and many reinforced concrete structures in these areas are exposed to chloride aggressive marine environments. Therefore, it is important to provide protection and offer appropriate repair methods of buildings vulnerable to the degrading effects of corrosion. The present study sets out to identify and evaluate the causes and extent of corrosion observed in Piers 11 and 12 in Imam Khomeini port, Iran. The microsilica is used to reduce corrosion. In order to achieve the above-mentioned goals, a number of experimental field tests were performed to determine the level of concrete condition in terms of reinforcement corrosion. Some tests were conducted to determine the conditions of concrete piers in terms of reinforcement corrosion. Then a reinforcement corrosion current density test is performed using a potentiostat involving a placement process; with different water-to-cement ratios and superplasticizers, the microsilica content was 5%, 10%, and 15%. Microsilica can serve as an alternative to cement and was measured according to the ASTM standards. Microsilica was exposed to aggressive conditions at different periods and a concrete compressive strength test was performed. The results showed that the compressive strength and corrosion resistance of the concrete increased for concrete mixture containing 10% microsilica with a water-to-cement ratio of 34% and a superplasticizer ratio of 6%.

The following is an in-depth study discussing various aspects of a sustainable Pavement Quality Concrete (PQC) mix with inclusion of Recycled Concrete Aggregates (RCA) and mineral admixtures. In addition to investigation of basic mechanical properties; compositional, morphological and interspatial aspects of hardened concretes were analysed to understand the macro and micro level effects of incorporating fine particulate fly ash, rice husk ash or bagasse ash in concrete mix having recycled concrete aggregates using state of the art techniques such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Mercury Intrusion Porosimetry (MIP). The study of PQC mixes prepared with assimilation of RCA and mineral admixtures show that addition of particulate mineral admixtures significantly enhanced the compressive and flexural strength of the mix incorporating RCA to the order of 15% and 25%, respectively. The study concluded that admixing mineral admixtures at 15% dosage refined the pore structure by reducing the average pore size by up to a few microns and also reducing the total pore volume which indicates towards the concrete mix being less permeable. This refinement in pore structure of concrete mix resulted in reduced water absorption and higher density values thus indicating improvement in durability of concrete.

Subjected to external loads, granular materials experience severe deformation in a narrow zone before their failure. This phenomenon, which is called strain localisation or shear band, is of vital importance in assessing the stability of the geotechnical structure, studying the stress-strain behaviour of soil and rock materials, and analysing the interaction of soil and structure. The present study is aimed to investigate the effect of various factors on the pattern and inclination of shear band in a general three-dimensional condition of stress using the Discrete Element Method (DEM). Several tests were simulated using a developed version of the TRUBAL program called GRANULE. The GRANULE code was further developed to add the capability of carrying out simulations with different intermediate principal stresses and modelling specimens containing non-spherical particles. The shear band was detected by tracking the motion of the particles and plotting the rotation distribution of particles within the sample. The results prove that the shear band inclination and its pattern, are greatly affected by intermediate principal stress, particle shape, and confining stress. Moreover, it was observed that the change in the b value plays a key role in the alteration of the 3D configuration of the shear band.

One of the layers that is applied on the base layer in asphalt pavements and increases the cohesion between the two layers, is the prime coat layer. Due to the fact that there are usually problems with the prime coat penetration into the base layer and penetration is not usually done well, there is a need to identify the factors affecting the penetration into the base layer. In this study, the penetration rate of prime coat coatings made of emulsified bitumen CSS-1h on the grain base level with different aggregate grading (aggregation close to the lower, middle and upper limits in two different types of aggregate grading) and different compaction levels were examined. Optimum water content, density, California Bearing Ratio (CBR) and the permeability of the samples were also examined. According to the results, the compressive strength of stone materials samples increases with approaching the upper limit (fine grain) and increasing the compaction. Also, increasing the grain size and decreasing compaction, increases the prime coat penetration rate, so that the 90% compacted sample with aggregate grading Type 3 has the highest penetration rate. The effect of moisture is obvious on the prime coat penetration, so that prime coat penetration rate is greatly reduced in saturation mode, but moisture in the base layer can help the prime coat to penetrate into the base layer.