Iraqi Journal of Civil Engineering

Traffic movement is considered a compound phenomenon that is impacted by behavioral, economic, and physical aspects. It is performed within the context of an urban system that consists of road networks and crossings, where the movement crouches to depend. The measuring of identifying their size and densities and current problems helps to Improve and development for roads and streets network existing and important intersections for purposes the accessibility, potentiality of future intersections, and network development towards constructing a composition to raise the quality and the efficient performance of roads and streets. The study was dependent on a traffic survey for intersections, areas of urban intersections, and the road network of Al-Ramadi city, as well as the number of vehicles that generated a large volume of traffic flow. The use of the program (HCS 2010) to detect appropriate for purposes decreasing traffic congestion and delayed trip time in the areas based on existing and future districts that generate different types and purposes of journeys to lessen the delay trip time to lessen traffic congestion. Therefore, research looks at both sides: first, a study of the existing intersections of the main road network and urban streets, including an examination of the components and shapes of these intersections in the study area; second, an examination of the importance placed on these intersections by the planning and design process.

The accumulation of waste, especially plastic and car tires, has become a major problem facing society today. Therefore, through this research, these wastes were recycled and used to improve some properties of concrete. Recycled crumb rubber from car tires was used instead of sand as a 10% partial replacement. The substitution was done by two methods: random and equivalent-size substitution. As well, 1% polyethylene terephthalate (PET) fiber was added to the volume of concrete to improve some properties of rubberized concrete. Compressive strength and ultrasonic pulse velocity tests (UPV) were conducted in this study to investigate the efficiency of PET rubberized concrete. An impact resistance test was also conducted to investigate the ability of PET rubberized concrete in terms of energy absorption. Slabs of size 50 cm×50 cm×5 cm were utilized for low-velocity impact tests. The results indicated there was a reduction in compressive strength, and UPV results were observed in PET fiber rubberized concrete. The reduction was 37.47% and 5.4%, respectively, as compared with the PETC mixture, and the result of the dynamic modulus of elasticity showed the same pattern as that of the UPV test. In contrast, there was an improvement in the impact resistance when PET fiber and crumb rubber were used; it increased by 117.63% and 52.9% for random and equivalent replacement, respectively, as compared with PETC.

The analysis of the least compressive load that cause buckling failures of Euler-Bernoulli beams resting on two-parameter elastic foundations (EBBo2PFs) is vital for safety. This article presents Ritz variational method (RVM) for the stability solutions of EBBo2PFs under in-plane compressive loads. The Ritz total potential energy functional, was derived for the problem as the sum of the strain energies of the thin beam, the two-parameter lumped parameter elastic foundation (LPEF) and the work potential due to the in-plane compressive load. Ritz functional was found to depend upon the buckling function w(x) and its derivatives with respect to the longitudinal coordinate. The principle of minimization of was implemented for each considered boundary condition to find the w(x) corresponding to minimum Three cases of boundary conditions investigated were: clamped at both ends, clamped at one end and free at the other, simply supported at both ends. For each case, w(x) was found in terms of unknown generalized buckling parameters ci, and buckling shape functions satisfying the boundary conditions. Thus was expressed in terms of the parameters ci. The Ritz functional was subsequently minimized with respect to the parameters yielding an algebraic eigenvalue problem. The condition for nontrivial solutions of homogeneous algebraic equations was used to find the characteristic buckling equations that were solved to find the eigenvalues. The eigenvalues were used to find the buckling loads and the critical buckling load. It was found that a one-parameter RVM solution for the EBBo2PF with both ends clamped, and with one clamped and one free end gave similar critical buckling load solutions to those presented in the literature. It was also found that an n-parameter RVM solution for the EBBo2PFs with both ends simply supported yielded exact buckling load solutions because exact sinusoidal buckling shape functions were used.

Local scour is a primary cause of bridge collapse, presenting a complex challenge due to the numerous factors influencing its occurrence. The complexity of local scour increases with clay-sand beds, particularly in predicting scour depth, as empirical equations are inadequate for such calculations. This study aims to predict local scour around cylindrical bridge piers in clay-sand beds using an artificial neural network (ANN) model. The ANN model was developed using 264 observations from various laboratory experiments. Eight variables were included in the ANN model: clay fraction, pier diameter, flow depth, flow velocity, critical sediment velocity, sediment particle size, bed shear strength, and pier Reynolds number. Sensitivity and statistical analyses were conducted to evaluate the impact of each variable and the accuracy of the ANN model in predicting local scour depth in clay-sand beds. The findings indicate that the ANN model predicted local scour with high accuracy, achieving a mean absolute percentage error (MAPE) of 14.6%. All dimensional variables significantly influenced the prediction of local scour depth, particularly clay fraction and bed shear strength, which were identified as the most crucial parameters. Finally, the MAPE values for local scour depth calculated using empirical equations were significantly higher than those for the ANN model, leading to an overestimation of local scour depth by the empirical equations.

Collapse of gypseous soils may cause excessive settlement and serious damage to engineering structures. Various improvement approaches, such as mechanical techniques and chemical additions, have been used to reduce the collapsibility of these soils. The odometer test has traditionally been used to assess the collapsibility of the improved gypseous soils; however, because the small size of test specimens, this method may not adequately reflect field conditions. In this research, a laboratory model test of 600 x 600 x 600 mm with a model footing of 100 x 100 mm was developed to measure the collapse characteristics of a gypseous soil. The top layer underneath the footing was improved by compaction, cement kiln dust (CKD), geogrid, and a combination between CKD and geogrid. The top layer was improved at two values of thickness of 50 and 100 mm. The results obtained from this study indicate that the values collapsibility settlement reduction factor for compacted soil and the soil treated with CKD were 75 and 82%, 89% receptively. These values increased up to 95 % when a combination of CKD and geogrid was applied. As discussed herein, the aforementioned treatment methods can effectively be used to improve the collapsibility of gypseous soils.

This study investigates the strength performance and microstructural changes of a sandy gypseous soil improved with fly ash-based geopolymer, for shallow and deep applications. Different proportions of geopolymer were added to a natural gypseous soil having a gypsum content of 30% to 40% with different water contents. The fly ash was activated using sodium hydroxide with molar concentrations of 8 and 12 and sodium silicate. The ratios of the fly ash to the activator were 1 and 2. Specimens were cured for different ages at 30°C. To simulate the field conditions, a number of specimens were immersed in a salt-saturated solution. Materials performance was evaluated at the macro level by performing unconfined compression test and at micro level by performing scanning electron microscopy test. The study showed that an increase in the molar concentration of sodium hydroxide and of the binder ratio improved material’s strength particularly at lower water contents of the soil. Increasing the binder content to about 30% improved the strength by enhancing the bonding between the soil particles. On the other hand, immersing the samples in the salt solution led, in most cases, to breakdown of the geopolymer network, as confirmed by the SEM images. It was concluded that the fly ash geopolymer-soil mixtures under investigation can provide as high as 8 MPa uniaxial strength under no sulfate attack. However, under sulfate attack condition, this strength can decrease to as low as 0.5 MPa. Even under the worst case, the later strength can be just enough to support shallow foundations rested on a saturated gypseous soil.

This paper attempts to obtain bending solutions to plates under uniformly distributed and hydrostatic load distributions using Ritz variational methods and basis functions that are found by superposing trigonometric series and third-degree polynomials. Two cases of boundary conditions were considered. In one case, three edges were simply supported and the fourth edge was clamped (SSCS thin plate). In the second case, the adjacent edges were clamped and the other edges were simply supported (SCCS thin plate). This work presents first principles, rigorous derivation of the governing Ritz variational functional and the displacement basis functions for the boundary conditions investigated. The solution is presented in analytical form. The obtained results are compared with previous results obtained using Levy series and Ritz methods and found to be in close agreement. The disadvantage of the method is the associated computational rigour, but the benefit is the accuracy of the results. Comparisons of the present results for center deflections and center bending moments with results in the literature show that there is negligible difference. Double series expressions were found for deflections and bending moments for the plate bending problems solved. Evaluation of the double series expressions at the plate center gave center deflection results that differed from the exact solutions by for to for for uniformly loaded thin plates with three simply supported edges and one clamped edge (SSSC). The differences in the center bending moments Mxx were found to vary from for to for In general, the present results yielded reasonably accurate solutions for the plate bending problems studied.

The evaluation of the undrained shear strength (Su) in fine-grained soils plays a critical role in the context of geotechnical engineering applications. The introduction provides an overview of the significance of Su in the field of geotechnical engineering and highlights the complexity of estimating Su in fine-grained soils. This data was collected from multiple sources, which encompassed consulting engineering offices (collected from the soil test laboratories at the University of Anbar), private contracting companies, and various offices. Data collection is an indispensable step in attaining optimal outcomes. from Fallujah, which predominantly consist of silty clay and clayey silt. Field investigations were conducted to obtain Su values using field vane shear tests. the field-testing data, including borehole depth, SPT results, consistency, Su, Su from SPT NOVO, and soil description. The testing program involved determining the undrained shear strength of the soils using appropriate testing apparatus and procedures. The data acquired from the laboratory experimentation are analyzed to identify trends in Su and soil consistency. Based on the examination of the data, and the results obtained from the laboratory testing, it can be concluded that there is a relatively weak correlation between the undrained shear strength (Su) and the Standard Penetration Test (SPT) N-value. The correlations proposed by (Sowers 1979, Kulhawy 1990, Reese et al. 1976, and Terzaghi 1967) all show modest R2 values, indicating limited correlation between Su and N-value.