Civil engineering reopsitory

ABSTRACT Weak soils, such as loose sand, have high compressibility and low shear strength. Construction on weak soils often requires utilization of ground improvement techniques. However, cement and lime, which are the most common used binder, are the major contributor of CO2 and have sever impacts on the environment. Recently, the construction industry immense pressure to come up with materials and processes that are ecofriendlyand promote sustainable development. Therefore, this research deals with improving the performance of the weak soil in term of increasing it strength using sustainable materials. Two approaches have been employed in this study. The first one dealt with investigating the performance of soil improved by (cement kiln dust, calcined clay, and alkali activator) considering various percentages of Alkali material and activator ratios. While the other approach investigated the using of such sustainable materials as a binder to improve the bearing capacity of the soil by the deep mixed columns, experimentally and numerically.The first approach showed increasing the unconfined compressionstrength of the soil with increasing the Alkali material, cement kiln dust,for all the activator ratios. Cement kiln dust-soil Alkali of 0.4 MPa compared with 0.0167MPa of the untreated soil. Incorporating the calcined clay, which is an alumina-silicate enriched material, consequence of pronounce improvement, where the strength increased drastically to about 3.57MPa when calcined clay/Alkali material= 0.5. Regarding the activator ratio, the optimum ratio necessary to activate the inert cement kiln dust and calcined clay is 0.5, beyond that there is a slow increase or decrease in the strength, depending on the Alkali material content.In the second approach, tests performed using pilot field models, the diameter of column = 15cm and its height = 150cm, revealed clearenhancing of the performance of footing resting on soil reinforced by deep sustainable mixed columns. Compared with bearing capacity ofunreinforced soil of 88 kPa, the bearing capacity of square footing (B = 75cm) increased by 50, 126, 223, 243, 338, 324, 328, 365, and 385%corresponding to reinforcing the soil with 1, 2, 4, 6, 8, 10, 12, 16 and 20 deep soil mixing columns, respectively. However, when the load was applied on the column only and not the surrounding soil, the bearingcapacity was 16 times that of the untreated soil. The results of this approach were verified numerically using PLAXIS 3D software.

This research aims to experimentally investigate the flexural behavior of reinforced concrete beams with hybrid fiber. For this purpose seven mixes were studied, one control mix without fibers and six hybrid fiber mixes were prepared consisting of different ratios of steel fibers and polypropylene fibers. Steel fiber crimped was an aspect ratio 50 and volume fractions of 0.5%, 1%, and 1.5% , while the polypropylene fiber used had an aspect ratio 375 and volume fractions of 0.15% and 0.3%. Superplasticizer was added in a ratio of 1.5% and the ratio of water to cement was constant in all concrete mixtures and equal to 0.47. In the present study, cubes (150 x 150 x 150)mm were casted for compressive strength test and cylinders (150 x 300)mm to obtain the compressive stress-strain diagrams for each mix. Fourteen reinforced concrete beams with dimensions of (120 x 200 x 1200) mm were casted. All beams were tested under three point loading, seven beams under the static load and the other seven under the repeated load . The load-deflection curves characteristic, ultimate load, and cracking behavior were observed and studied. Additionally, the effect of hybrid fibers on concrete properties has been investigated, and failure patterns in specimens were recorded and discussed intensively. The experimental results indicated that the increase in the hybrid fiber content led to decrease of the workability. All concrete mixtures showed improvement in compressive strength test results due to the effect of the hybrid fiber on the final resistance properties. As a result of the effect of the hybrid fiber, the number of cracks has increased and the distances between them were reduced. However, the cracking pattern caused by the repeated loading was more segmented and extensive than the static loading pattern. These results indicated an increase in the ductility of the concrete and thus improved the structural performance of the beams. The load-carrying capacity of beams was increased by adding the fibers. The highest improvement in compressive strength and ultimate load compared to the plain concrete was 27% and 14%, respectively. This was obtained from including 1% of steel fibers and 0.3% of polypropylene fibers in the concrete mix. Repeated loading has no significant influence on the ultimate load-carrying capacity of the tested beams, but deflections and propagation of cracks increased successively. In addition to that, the vast majority of cracks number were occurred during the first loading cycle. Evaluation of the load-deflection curves of hybrid fiber reinforced beams under static and repeated loads that fibers contribute significantly to maintaining the structural integrity and stability of the concrete. The analytical equations were used in this study indicated the Zhang et. al (2018) analytical model give closer prediction of the flexural strength of beams with hybrid fiber than ACI 544 model. In conclusion the combining of polypropylene and steel fibers improves the multiple properties of a concrete mixture, which can contribute of the prolonging the service life of the building

Establishing geotechnical maps for Nasiriyah is essential for the preliminary design of soil foundations for any structure, especially with the increase in investment projects. They permit fast access to the engineering properties of soil, define the problematic soil, suggest suitable methods of improvement, detect the water table, and propose the type of foundation. In addition, offering prior knowledge and correlations for the soil parameters that greatly aid in reliability analysis and design of the geotechnical structures. In this study, a robust database of soil properties in Nasiriyah was considered based on data collected from 423 boreholes from several projects in the governorate. The data was analyzed using a geostatistics analyzer, represented by two methods: the Inverse Distance Weighted (IDW) and Kriging approaches. The results of the two methods were compared in terms of accuracy to create geotechnical maps by matching field results that were isolated for comparison and were not included in the calculations. The allowable bearing capacity qall of Nasiriyah soil was calculated according to the average results to computed by six methods, Terzaghi (1943), Skempton (1951), Hansen (1970), Vesic (1973), Meyerhof (1963), Eurocode7 (1996) and for three types of foundations (square, circular and strip). The correlations were made for different soil a property which helps in modern design. Relationships, graphs, maps, and equations were then linked to guide the geotechnical engineers when designing projects in Nasiriyah. On the other hand, the design characteristics of the strength variables of soil in Nasiriyah were determined, utilizing Eurocode 7 equations and Bayesian statistics. Various methods of determination for laboratory and field tests were expressed through probability distribution models and the reduction of spatial variance. The geotechnical maps, that were produced by applying Arc GIS (10.7.1) on an extensive database and based on two statistical methods: Kriging and IDW, demonstrated a good agreement with the results obtained using Python programs. The Kriging method yielded a 1% error rate, while the IDW method yielded a 7% error rate. With respect to the bearing capacity of soil, the lowest bearing capacity of soil in the region south of Nasiriyah was (57-94) kN/m2, and the highest a bearing capacity the eastern region of Nasiriyah was (290) kN/m2, while in the northern region was (94-124) kN/m2. For the correlations between soil parameters, the correlation between c and φ° is positive and medium. This relationship was based on 75 test boreholes at an Al-Gharf oil-producing facility. However, the value of the angle of friction in most other Nasiriyah projects approaches zero and is occasionally ignored. To create a reliable design, the average values of soil parameters are not enough, and the number of data and the variance of the site must be taken into account. In a Bayesian analysis of typical soil parameters, the ordinary, normal distribution (OND) method produced results similar to those of the bivariate normal (BV) method, with a marginal difference due to covariance. The maximum posterior density (MPD) technique presupposes that the bivariate posterior probability distribution is expected in approach Bayesian, the process of MPD outcomes are comparable to those of the analytic solution. The kriging method produces more precise results, forecasting data in the preliminary design and making prior data. It's used in a Bayesian approach to provide the final design within an accurate, dependable, and economically distinct value.

During the last few decades, many studies have been conducted to assess the shear performance of steel fiber RC beams. However, most of the previous works have not taken into account the effect corrosion of main steel on the shear behavior of RC beams incorporated with corroded and non-corroded steel fibers (SF). In this research, the corrosion effect on the shear behavior of steel fiber RC beam has been studied experimentally and numerically. The experimental program includes the test of nineteen beam specimens with dimensions of 100 x 150 x 1300 mm to evaluate the shear behavior of steel fiber-reinforced concrete (SFRC) beams exposed to corrosion. The tensile reinforcement of the specimens was subjected to 7% and 20% corrosion rates. Volume fractions of steel fibers of 0.8%, 1.2%, and 1.8% were added to the concrete mixes. Four beams were the referenced RC beam with and without shear reinforcement. Two of these beams which without stirrups exposed to 7% and 20% corrosion process. The other three beams without stirrups contained 0.8%, 1.2%, and 1.8% steel fiber did not exposed to corrosion process. While, six beams have contained the same three volume fraction of non-corroded steel fiber subjected to 7% and 20% corrosion, another six beams were mixed with pre-corroded steel fibers at a corrosion rate of 50% to investigate the hybrid effect of the longitudinal reinforcement and steel fiber corrosion on shear performance. The analysis of results was focused on the shear capacity, crack initiation and propagation due to corrosion, mode of failure and midspan deflection. It was noticed experimentally that the shear capacity of the non-corroded SFRC beams increased by about 68%, 72%, and 82% for the 0.8%, 1.2%, and 1.8% volume fractions of steel fiber, respectively, compared to RC beams without fiber. Also, the mode of failure was changed from brittle shear failure to flexure-shear or flexure failure for SFRC beams. The improvement of the shear behavior increased with the increase of volumetric ratio of steel fibers. The corrosion in the tensile reinforcement of the beams reduced the load carrying capacity of RC beams by 6%-8% for the corrosion rates of 7% and 20%, respectively. The corrosion also reduced the load carrying capacity of SFRC beams by 10%-22%. Furthermore, both the corroded steel fibers and corroded bars reduced the loads by 6%-37%. A computer system program (ABAQUS 6.14) was used to develop a finite element model for the analysis of the RC and SFRC beams with and without corrosion effect. The proposed model was validated by using the results of experimental study of RC and SFRC beams of this study. It was found that there is a good convergence between experimental and numerical results. The maximum difference in ultimate shear capacity between the numerical and experimental results was 5%. The simulated model results showed a clear positive effect of the use of the SFs in the RC beams by reducing the deterioration when subjected to corrosion compared to the reference beam. Finally, it can be concluded that SF can enhance the shear performance of the beams even in a harsh environment.

A static pile load test (SPLT) can be considering the best choice to determine the pile foundation bearing capacity (BC). However, interpretation methods of SPLT give different results for the ultimate BC value (Qu), and the test takes a long time. For the preliminary design of piles, the Standard Penetration Test (SPT) based design methods can be used. Still, the predictions of SPT methods provided a significant difference in the resulting values compared to the actual value computed based SPLT. Therefore, the main objective of this research is to evaluate these methods and propose a modified framework to estimate the BC based on SPT results. The suggested framework requires determining the failure zone of the piles by using the finite element method (FEM) and finding the best method to determine the appropriate factors for the soil in Nasseriyah. The research considered 22 piles in different areas of the city of Nasseriyah in southern Iraq and included data analysis using fifteen methods to interpret the loads resulting from the SPLT. Then the value of the ultimate bearing capacity (BC) of the pile was predicted by applying seven direct methods of SPT. Three criteria have been used to evaluate direct SPT methods: best fit line, mean, standard deviation and log distribution curve. Also, the FEM has been used for single piles to analyze the behavior of the pile subjected to vertical load and produce the pile load-settlement (Q-S) curve. The method of analysis using the FEM offered possibilities to determine the depths of failure of the piles, which provided the opportunity to determine the limits of failure for each pile. Then, an equation was proposed to calculate the BC of the pile. In addition, FEM was applied to a group of piles as a case study. Finally, a reliability analysis was performed to update the resistance factors used in load resistance factors design (LRFD), utilizing both measured ultimate bearing capacity and predicted ultimate bearing capacity depending on SPT. It was concluded that some methods of interpretation, such as Shen and Buttler, did not give a clear visualization of the failure curve of the piles and others such as Chin-Kondner and Decourt could be used to complete the failure curve of the piles. It was also found that the Chin-Kondner method gave the highest Qu while the Buttler method provided the lowest load. With respect to SPT direct methods, they provided a high BC of piles while the proposed equation with modified factors gave Qu with a coefficient of variation (COV) value of 10% for twelve piles and 33.3% for the other ten piles as evaluated by three criteria. Concern to the effective zone limits of piles computed by FEM, it was concluded that the limits of the effective zone of the piles for clay (8.4B above the base of the pile and 6.46B below the base) with the dispersion 2.3% and 1.4% for above and below the end pile, respectively. The effective zone of piles in sand (4B above the base and 3.65B below the base) with the dispersion of 0.43% and 0.4% for above and down the end pile, respectively. The proposed SPT-based design method in this research was also verified for a case of group piles that showed a good agreement with FEM. Finally, the resistance factor for piles based on the proposed equation gave a value of 0.43, which can be used in the LRFD method.

Strengthening is becoming the most popular way of enhancing the capacity of Reinforced Concrete (RC) beams. Steel plate is one of the most typical materials used for strengthening of RC structures. This research focuses on using the steel plates internally to improve the flexure performance of simply supported RC beams. Compared to other strengthening techniques, using steel plates provides very slight increase in the weight of the strengthened elements, in addition, this technique does not change in the structure's appearance. Furthermore, using it does not require high skills or special workers. In this research, experimental and numerical investigations on strengthening of RC beams with different configurations of internal steel plates were carried out and its contribution to flexural behaviour was obtained. Eighteen reinforced concrete beams were cast and cured for 28 days. The steel plates were fixed at the tension side of the RC beams to investigate their effect on the flexural behaviour of the tested beams. To achieve the research objectives, three configurations of the shape of steel plates were proposed: flat, curved and rounded. In addition, two holes were made in each piece of steel plates to enhance the bond between steel plates and concrete, and to decrease the weight of them. The results showed that the higher load-carrying capacity was achieved using flat steel plate by an average of 54% compared with the reference beam. Furthermore, using flat steel plates provided higher enhancements in flexural behaviours such as ductility, elastic stiffness, and toughness by 200, 22.84 and 621%, respectively, compared with the reference beam. Similarly, constrained the flat, curve, and rounded steel plates with lateral steel plates provided a high load-carrying capacity, ductility, elastic stiffness and toughness. For instance, constraining the flat steel plate with two inclined steel plates by 45o on both sides improved the ultimate load, ductility and elastic stiffness by 7.6, 3.16 and III 35.65%, respectively compared with non-constrained specimen. Regarding the effect of steel plate’s thickness, the load-carrying capacity and other flexural behaviours enhanced with the increase of thickness, except in the rounded steel plated specimens. The numerical part included modelling and verifying the results of eighteen reinforced concrete beams using (ABAQUS) finite element program. A parametric study included compressive strength of concrete, yield strength of steel plates, degree of curvature of steel plates and existence of holes in steel plates were also conducted. An acceptable match has been obtained between the experimental and numerical results, which proves the adequacy of the simulation process. And the maximum difference between the numerical and experimental ultimate loads was 6.13%. Also, there was an agreement in crack pattern and modes of failure between numerical and experimental beams. From the experimental and numerical investigations, it can be concluded that using flat steel plate with 6 mm thickness and constraining the plate with two 45o inclined steel plates enhances the bond between steel plates and concrete and results in improving the flexure behaviour. Also, in the case of using curved steel plates, it can be concluded that beams with curved steel plate showed improvement in the load-carrying capacity. However, it was slightly lower than its comparable flat steel plate. Furthermore, the height of the curve must be less than the neutral axis depth to achieve the best effect on flexure behaviour.

Numerous types of structures have been retrofitted and rehabilitated using carbon fiber reinforced polymer (CFRP) composites. The common method of strengthening is Externally Bonded Reinforcement (EBR), however this method has a main problem which is debonding issue. Recently, alternative methods were presented to delay or eliminate the deboning issue such as Externally Bonded Reinforcement on Groove (EBROG). In this study, ten reinforced concrete (RC) beams with dimensions of 1200 mm in length, 170 mm in depth and 120 mm in width were investigated. One beam was un-strengthened (reference beam) and nine beams were strengthened with CFRP sheets against shear and tested under four-point loading. Three strengthening techniques have been considered in this research; EBR, EBR with longitudinal anchoring (center or upper and lower anchoring) and Externally Bonded Reinforcement on Grooves (EBROG). Three beams strengthened by EBR method, two of those beams with CFRP sheet anchorage. The remaining six beams were strengthened by grooving method. Number of layers, grooves shape and surface preparation are considered as variables of this study. The test results indicated that EBROG strengthening technique leads to improve the shear capacity in comparison with EBR method. Besides, test results demonstrate that EBROG method performed better than EBR; as a result, debonding of CFRP sheet are eliminated for all beam specimens strengthened by EBROG technique. Two layers of CFRP and vertical and horizontal grooves comparing to the vertical groove attained a little additional gain in shear capacity for strengthening beams. The improving in shear capacity for beam strengthened by EBR was 2%, while the improving in the capacities of beam specimens strengthened by EBR method with anchoring ranged from IV 13% to 25%. In addition, EBROG method improved the capacities of the beams by 12% to 28% comparing to the un-strengthened beam. The results of some of the available design codes and guidelines for calculating the CFRP contribution to the shear strength were presented. It was observed that the predicted results obtained from ACI-440.2R- 17 and Chen model- 2010 match well with the experimental results while the predicted results obtained from CNR-DT 200 R1, Fib Bulletin 14, Chen model -2003 and Dias and Barros model were overestimated

The solar cooker is one of the best, easiest and cheapest ways to use the solar energy to cook food or boil water for sterilization, heating and other uses is to use a solar cooker. The technical solutions of solar cookers will be of great value to solve the problem of the effect of the use of fossil fuel and its high prices, the increase of desertification and the elimination of environmental and health problems. The present work was done using four parabolic solar concentrators manufactured using a parabolic dish, three of them with diameters (96 cm, 120 cm, and 140 cm) with a reflector made of aluminum foil. The fourth solar concentrator was (96 cm) in diameter with a reflector from pieces of mirrors. Metal tin cans with four volumetric capacities (1 liter, 2 liters, 3 liters, and 4 liters) were used as a thermal receiver coated with black paint were used to increase the absorption of concentrated sunlight falling on the surface of the thermal receiver. Seven experiments were conducted on each thermal receiver, four experiments were conducted using the four concentrators separately, while the remaining three experiments were conducted by collecting the solar concentrator of a diameter of (96 cm) with a reflector of aluminum foil with the rest of the solar concentrators, where the data for each experiment are measured and recorded (the experiment time (t), the beam solar intensity (𝐼𝑏) falling on the concentrator aperture area (𝐴𝑎), the water temperature (𝑇𝑤), the surface temperature of the thermal receiver in the place of the concentrated solar incident on it (𝑇𝑎𝑏𝑠), the ambient air temperature (𝑇𝑎𝑚𝑏) and ambient air velocity (𝑉𝑎𝑖𝑟) for calculating the important parameters of the parabolic solar cooker, which are (the optical efficiency (𝜂𝑜) of the solar concentrator, the amount of heat received by the aperture of the solar concentrator (𝚀𝑠), the heat losses from the receiver by radiation and convection (𝚀𝑙𝑜𝑠𝑠), the amount of useful heat used by the receiver (𝚀𝑢𝑠𝑒𝑓𝑢𝑙), the collector efficiency (𝜂𝑐), overall thermal efficiency (𝜂𝑢) and cooking power (P)). The experiments were conducted from the roof of the house in Nasiriyah city, southern Iraq, from September 2020 until April 2021. The following results were reached : The optical efficiency of the solar cooker depends on the quality of the reflective material used in the concentration dish, the quality of the surface of the receiver, and the quality of its coating, in addition to the area of the receiver shade reflected on the concentration dish. The amount of concentrated heat reflected by the concentration dish affected by the diameter of the dish, its optical efficiency, the quality of the reflector used, and the accuracy of tracking the sun. It was observed that the thermal losses increased with the increase in the focus area on the surface of the receiver, the increase in the velocity of the ambient air, and the increase in the temperature of the receiver surface, meaning that the ambient conditions greatly affect at the increase in thermal losses. As for the amount of useful heat used by the receiver, it increased with an increase in the diameter of the concentration dish, the quality of the reflective material, and the reduction of thermal losses. It was the highest possible when combining two solar concentrators. The collector efficiency or concentration efficiency was high by increasing the diameter of the concentration dish, combining two concentration dishes, increasing the optical efficiency, reducing thermal losses and accurate tracking the sun, and it was highest possible when combining two solar concentrators. The overall thermal efficiency was affected by the cooking period, the mass of water used, the combination of two concentration dishes, the diameter of the concentration dish, the amount of solar radiation captured by the reflector and the accuracy of tracking the sun too, and the overall thermal efficiency was greater when combining two solar concentrators. The cooking power increased by increasing the mass of water or food prepared for cooking and reducing the cooking time. Despite the low overall thermal efficiency and cooking power of the solar cooker, it is recommended for its easy manufacture, low financial costs, and no harm to humans and the surrounding environment.

The thesis starts from the need to identify methods, materials, techniques that can contribute to the reinforcing of the reinforced concrete structure. The thesis presents the results of the experimental investigation on the shear performance of beams reinforced with different types of grids (i) GFRP (Glass Fiber Reinforced Polymers) mesh, (ii) geogrid, and (iii) steel mesh. The experimental work reports the test results of twelve reinforced-concrete (RC) beams reinforced internally, with dimensions of 1200mm in length, 150mm in width, and 200mm in depth, are constructed and tested up to failure using a symmetrical four-point loading system. One beam is considered as a control beam and the other beams are divided into three groups; the first group consist of four beams which is reinforced by GFRP mesh while the second group has three beams reinforced with steel mesh and the remaining beams of the third group, reinforced by Geo-grid materials. Experimental results of load, deflection and failure modes of all the tested beams are obtained. Various parameters are considered in this study including the number of mesh layers, the type of reinforcement material mesh, and the reinforcing configurations. All beams failed in diagonal shear failure due to slip and rupture of mesh. The test results indicate that the beams reinforced using steel mesh as shear reinforcement give high performance than any other specimen where they improve the load-carrying capacity up to 66% higher then that of the control beam. While the development in the ultimate load for reinforced beams using GFRP ranges from 1% to 18% compared to the control beam. finally, the experimental results show Insufficient improvement in the ultimate load for beams that reinforced using Geo-grid type

Flexural behavior of reinforced concrete beam specimens containing horizontal cold joints at variable levels was discussed in this study. Cold joints in reinforced concrete elements can be formed due to many reasons. Lack of concrete quantity delivered to the site, accidents or problems happened while pouring the concrete, massive infrastructures that are very difficult to be poured continuously, rejecting “out-of-specifications” concrete patches, etc. all can consequently cause the formation of cold joints. To achieve the goals of the study, sixteen rectangular reinforced beams with overall dimensions of 1200 mm in total length and a rectangular cross- section of 160 mm × 100 mm were cast and tested as simply supported beams under two-point loading. The beams have been designed to ensure that flexural failure is the mode of failure. Sixteen RC beams were divided into four groups and examined according to the time of cold joint ,location of cold join , compaction process and use steel fiber to strength : Thirteen beams , divided into three categories: one control beam (without cold joint , without steel fiber)and twelve divided into three group, each group contains four beams according to the difference in the time elapsed between pouring the two layers: two with horizontal cold join at compression fiber ,two with horizontal cold joint at tension fiber and whether the first pour had been compacted before pouring the second patch have been investigated as well. The second pour in the first group (G1) has been done after 1.5 hour after the first pour. Similarly, the second pour in groups (G2 and G3) have been done after 3.0 and 4.5 hours after the first pour, respectively., Furthermore three beams were cast by choosing the least failure load and strengthening the joint interface with steel fiber of 1.0% volume ratio as a trial to enhance the behavior of joint interface.II The main parameters of this study are the effect of time elapsed between the first pour and the second pour, the effects of location of the joint, the effect of compaction of the first RC layer and addition of steel fiber. The experimental results showed that a longer time delay between the first and second pours may result in a larger decrease in the total capacity, it can also be noted from these results that compacting the first layer prior to pouring the second layer in the first two samples has provided for a better behavior than leaving the first layer uncompacted. The location of the cold joint, on the other hand, has also influenced the load carrying capacity and midspan deflection. A significant reduction in the flexural loading capacity has been reported when the joint is located at the compression zone of the beam’s cross section (i.e., at 0.7h), especially when the first pour had been left uncompacted. It was found that the presence of cold joints has decreased the ultimate load and ultimate deflection, ductility, stiffness and toughness in comparison to reference beam. The decrease in the ultimate load and ultimate deflection were by about 40.91% and 43.4% when the time between pours has been changed from 1.5 to 4.5 hours, when the cold joint located at the compression fiber and when the first layer had not been compacted. The test result also showed that adding 1.0% hooked-ends steel fiber of aspect ratio equals to 50 for beams with horizontal cold joint it can provide for better bonding between concrete layers, and therefore, increase, or restore, the lost flexural capacity of the beams with cold joints.

The research goal is to investigate the flexural behavior of Warren vertical truss girders infilled with self-compacting concrete experimentally. Ten simply supported truss girders including eight concrete filled steel tube (CFST) truss girders and two hollow tube trusses were tested under third-point bending. The test parameters were the presence of concrete infill in the chords, the addition of reinforcing steel to the concrete core in the lower chord, and sectional types (circular and square). The tested specimens were classified into five groups. The first group was a hollow tube with no concrete filling. The second group of specimens was filled with concrete with no reinforcement in the lower chord. The third group of specimens was reinforced with (1Ø10mm) steel bar in the lower chord. The fourth group of specimens was reinforced with (2Ø10mm) steel bars in the lower chord, and the fifth specimen was reinforced with a circular steel tube with a diameter of 55mm and a thickness of 1.0mm. The steel tube section for each group described above was either square section or circular section. The concrete grade of (SCC) that filled the chords of CFST specimens was 50 MPa. Generally, the test results indicated that the CFST truss girders had higher ultimate load capabilities than their hollow truss girder counterparts. The ultimate load capacities increasing ranged from 50% to 117%. When the square type section of CFST truss girders was compared to the circular type section of CFST truss girders with identical reinforcement, the square type truss was higher in the ultimate load by about (48%- 63%). The adding reinforcement to the self-compacting concrete at the bottom chord increases the CFST strength by about 6 % to 27 %. The best increase in Abstract ultimate load comes from adding a circular steel tube by about 15% and 27% for square and circular steel tubes of CFST truss girders, respectively.

Abstract Externally Bonded Reinforcement (EBR) is the most common technique that is used to strengthen the RC members with Carbon Fiber Reinforced Polymer (CFRP) sheets. Recently, a new proposed technique named; Externally Bonded Reinforcement on Grooves (EBROG) has been presented as an alternative method to avoid or eliminate the undesirable debonding failure mode that is accompanying to EBR method. This research is devoted to investigate the effect of the strengthening techniques on the flexural behavior of reinforced concrete continuous beams externally strengthening with CFRP sheets in both hogging and sagging zones. An experimental and analytical study is presented in the current work on twelve beam specimens. All beams have a rectangular cross-section of (130 ×200) mm with two equal spans, each span with length of 1050 mm. The beam specimens are designed to have a longitudinal reinforcement of (2φ8 mm) steel bars at each compression and tension zones with a (φ8@60 mm) diameter bars as a shear reinforcement. The parameters of this study include strengthening methods (EBR and EBROG), length and layers number of CFRP sheets and number, length and direction of grooves, in addition to the effect of presence steel fiber in the hogging zone. The results showed that the EBROG strengthening method has highly effective in improving the load carry capacity of strengthened beams. The beams strengthened by one of CFRP using EBROG with three longitudinal grooves has an increasing in the load capacity by about (24.4%) than that of the same beam strengthened by EBR. The positive effect of adopting the EBROG as the strengthening technique on the ultimate load is more observing with increasing the formed grooves number. Using double layers of CFRP sheets results in an improvement in II the ultimate load, which be more significant in case of beams strengthening using EBROG method where the increasing ratio reached (87.2%) over the control beam. Decreasing in the length of grooves and CFRP layer leads to reducing in the ultimate load of strengthened beams. Changing the grooves direction from diagonal grooves to inclined grooved with 30o angle had a slight effect on the load carrying capacity. In addition, providing the tested beams with steel fiber in beam hogging zone in addition to CFRP sheet contributed with small increasing in the beams ultimate load. The mode of failure was changed from CFRP de-bonding in case of EBR beams to CFRP rupture, or to concrete cover separation in EBROG beams. The strengthened beams with CFRP sheets presented a more brittle behavior at failure than the non-strengthened specimen, but the beams strengthening by EBROG show more ductile behavior than that reinforced by EBR method. And also, this research introduces a comparison study to check the validity of ten existing different models to predict the ultimate load of beams strengthening with CFRP sheets in this study. It was found that the models introduced by the ACI 440.2R-17 and other checked models are appropriating to estimate the ultimate load of the beams externally strengthening using EBR method, but most of these significantly underestimate the load carry capacity of beams strengthening using grooving method. Both Toutanji et. al., and Li and Wu models are preferred to use in estimating the ultimate load of these types of beams because it shows close predicted load to the experimental ones

This study focuses on the use synthetic fibers and geotextile to improve the performance of soil supporting foundations. The research methodology was divided into two parts: the first part to assess the performance of the reinforced soil supporting the foundation through a comprehensive series of tests, including compaction tests, unconfined compression strength tests, CBR tests, and model footing load tests. The reinforcement materials used in this study include polypropylene fibers, glass fibers and woven geotextile. Fibers were randomly distributed within the soil, with five different ratios (0.6, 0.8, 1, 1.2, and 1.5%by weight of the soil) tested for their impact. The model footing load tests were conducted on a top layer reinforced with synthetic fibers at three thicknesses: 0.5B, 1.0B, and 1.5B (where B represents the width of the footing). Additionally, WG layers were added at varying distances and different parameters studied such as the optimum distance between the footing and the first reinforced layer, the number of layers. The second part included, experimental results of model footing tests conducted on soil reinforced with fibers and geotextile for shallow foundations was simulated with PLAXIS 3D. The maximum dry density decreased from 1.852 g/cm³ to 1.65 g/cm³ and 1.75 g/cm³ after adding percentage up to 1.5% polypropylene fibers and glass fibers, respectively. While the optimum moisture content did not show a significant change decreased from 15% to 14.7% and 14.9 %. after adding percentage up to 1.5% polypropylene fibers and glass fibers, respectively. And the results showed that the compressive strength of the soil were significantly improved when PPF and GF were used as reinforcing materials. The UCS value increased from 122 kPa to 458 kPa and 249 kPa after adding the optimum percentage 1.2% polypropylene fibers and glass fibers, respectively.Additionally, the CBR value slightly increased about 63%, 42%, after adding the optimum percentage1.2% PPF and GF. Also, the test results showed that the inclusion of PPF, GF, and WG can significantly improve the soil bearing capacity and reduce settlement. Concerning of polypropylene fibers and glass fibers, ultimate bearing capacity (qu) was clearly increased as the thickness of the improved layer increased. The (qu) of the top layer reinforced with polypropylene fibers and glass fibers increases about 51% and 62% at thicknesses of 1.5B, respectively. In the case of woven geotextile. It is concluded that the depth of the first layer effects on results. It is observed that BCR is initially increased up to the depth 0.35B and then gradually decreased, peaking at u/B = 0.35. The test results also showed that the BCR increased with increasing the number of reinforcement layers until a certain value three layers, the reinforcing effect becomes negligible. The Finite element method with the help of Plaxis-3D software showed that polypropylene fibers, glass fibers and geotextiles can be successfully used to increase the bearing capacity of soil. The optimal design criteria were also explored which may increase the use of these materials in the construction of foundations on reinforced soils.

The objective of the current work is to study the performance of circular and square concrete-filled steel tube (CFST) truss girders (Warren vertical truss type) incorporating lightweight concrete (LWC). Ten CFST specimens with varying shapes and the presence of internal bar reinforcements are tested experimentally under one point loading at the mid-span. The effect of these variables on load-carrying capacity, stiffness, ductility, longitudinal strain and, failure modes, are evaluated through experimental results. The ten specimens were divided into five groups, each group contented from two specimens. The first group of specimens was filled with LWC without any additional reinforcement in the bottom chord, the second group of specimens was filled with LWC with adding the reinforcing to the middle of the bottom chord by using (1Ø10mm) steel bar, the third group of specimens was filled with LWC with added reinforcing to the lower of the bottom chord by using (1Ø10mm) steel bar, the fourth group of specimens was filled with LWC with adding the reinforcing to the middle of the bottom chord by using (2Ø10mm) steel bars, while the fifth group of the specimens was filled with LWC with reinforcing by using (2Ø10mm) which were added to the lower of the bottom chord. The results showed that the trusses with square steel tubes show ultimate load higher than trusses with circular steel tubes by about 21.7% to 25.46%. Also, the CFST strength shows an increase by about 6.3% to 24.8% when has been added reinforcement in the lightweight concrete at the bottom chord. The addition of reinforcement to the lower of the bottom chord gives the best increase in the ultimate load. All the specimens failed in the joint through the testing.

ABSTRACT "Traffic calming" refers to the practice of reducing the amount of accidents on the road via the use of physical design measures and other methods. The goal is to decrease excessive speeding and other potentially dangerous driving practices in residential areas. The construction of speed bumps is one of the most efficient methods of limiting the speed of moving vehicles while simultaneously improving public safety. A field survey of the road network in Nasiriyah and its surrounding facilities was carried out, in addition to a comprehensive data collection that was used in the GIS program (ArcMap 10.7) to produce maps showing the different types of bumps and the mechanism by which they are distributed in Nasiriyah, taking into consideration the facilities and surrounding structures, as well as the facilities themselves. Ultimately, it was determined that the short bump is a centralized and most appropriate bump for the Nasiriyah road network due to the ease with which it can be obtained. Furthermore, it is regarded to be less costly than other types of bumps. The nature of the study areas roadways and service center make the usage of short bumps a more appropriate solution. Utilizing bumps to calm traffic in the city of Nasiriyah enhances the reality of the streets as well as adds civilized touches to the roadways and helps to clear the city of slums by using the proper kinds in the suitable places at the appropriate time.

في جميع البلدان ، تعتبر الطرق من أكثر العناصر الهيكلية المهمة. يجب الاهتمام بإدارة أعمال الصيانة وتنفيذها في الوقت المناسب من أجل الحفاظ على الارصفة بحالة جيدة ومستوى خدمة مقبول. يعتبر فحص حاله الطريق مفيدًا جدًا لتحسين قدرات نظام ادارة الرصف. الهدف من هذا البحث هو ربط قاعدة بيانات برنامج (PAVER) مع برنامج (GIS) من أجل أداء تحليل استغاثة لحالة الطريق وتطوير خارطة حرارية مرتبطة بالموقع الخرائط على أساس قيم مؤشر حالة الطريق (PCI) تم إجراء مسح بصري لمنطقة البحث لتقييم نوع ومستوى وكمية الفشل الحاصل. تم استخدام تطبيق PAVER 6.5.7 لحساب قيم مؤشر حالة الطريق لكل وحدة عينة بناءً على البيانات التي تم جمعها من المسح البصري. تم دمج البيانات التي تم الحصول عليها بواسطة برنامج (PAVER) مع برنامج (ArcGIS) لإنشاء خرائط حرارية باستخدام أدوات التحليل المكاني مثل أداة تحليل حالة الطريق (IDW). (IDW: قياس المسافات العكسية) تساعد الخريطة في اتخاذ أفضل قرار لصيانة مثلى لمنطقة الدراسة بناءً على قيم (PCI)، مع تمثيل كل فئة من قيم (PCI) بمختلف الألوان. يمثل كل لون في هذه الخريطة نوعًا مختلفًا من الصيانة ، حيث للون الأحمر يشير إلى أن الرصيف يحتاج إلى إعادة البناء ، واللون الأصفر يشير إعادة التأهيل ، والأخضر يشير إلى الصيانة الوقائية. قيم (PCI) الاكثر من 85 تشير إلى أن الرصيف في حالة ممتازة ولا يحتاج إلى صيانة. باستخدام الخرائط الحرارية ، يمكن للمستخدمين رؤية اماكن العيوب بالإضافة إلى قيم (PCI) الخاصة بتلك الاماكن ، وأسماء واتجاهات شوارع ، وعدد الوحدات التالفة بالإضافة إلى العيوب عدد في كل وحدة. بشكل عام ، الطريق المختار في مدينة الناصرية في حالة جيده نوعا ما، على الرغم من وجود بعض الترقيع والتجوية في اكثر الاماكن تقريبا ، والطريق يحتاج إلى اكساء بطبقة من الاسفلت.

Abstract A more recent additive layered manufacturing method is shaped metal deposition (SMD). The use of a heat source like a beam of an electron, laser, or electric arc and metal wire is a unique technique enabling layer-by-layer fabrication of net-shaped metal components. This study focuses on the effect of input process parameters on the maximum temperature generated in the deposited walls and its impact on the characteristics of the final products. An infrared thermometer device was used to study the maximum temperature that develops throughout the deposit process and its effects on microstructure, microhardness, and impact energy. Nine experiments were carried out based on the Taguchi orthogonal array and the selected feature matrix. The results showed that the temperature increases with an increase in the deposition current until it arrives at a maximum value of 828 C° but decreases with increased travel speed and wire feed ratio. At the same time, the frequency parameter did not have much effect on temperature. The average impact energy and microhardness of deposited components attained their maximum values, 111(J) and 456 (kg/mm2), respectively. The most suitable frequency range is within (125-250 Hz), making the process less defective and more stable. The grain size is a function of the heat input parameters and the frequency level. Thus, it can achieve refined grains with low current, high travel speed, and high cold wire feed. Impact energy improves by about 40% using a set of parameters as travel speed (5 mm/s), wire feed ratio 2.5, and frequency (250 Hz) in comparison to a group of travel speed (3 mm/s), wire feed ratio (1.5), and frequency (0 Hz) at the same the current of 160 A. Through the results of the experiments and variance of analysis (ANOVA), we found that the most important factor affecting the temperature was current; on the microhardness was the frequency; on the impact energy was the wire feed ratio and on the grain size, in addition to the heat input, was travel speed.

Abstract Predicting the release of pollutant concentrations into the atmosphere is essential in assessing potential environmental damage from industrial emissions. In order to solve the concentration equation for gases, it is necessary to determine as accurately as possible the velocity field and the intensity of turbulence at the atmospheric boundary layer in the region of interest. This thesis presents a numerical study to model the dispersion of pollutants from the stacks of the thermal power plant in Nassiriya, Iraq. The power plant operates on two types of fossil fuels (liquid and gas) and emits pollutants in the form of (CO, CO2, SO2, and NOX). A 3D mathematical model based on fluid mechanics equations is used with a modified standard k-ɛ turbulence model to calculate flow and scattering at the atmospheric microscale (for distances of several kilometers). In order to obtain the most realistic results with the mathematical model, it is necessary to consider essential phenomena related to scattering in the atmospheric boundary layer as well as the topography of the terrain. In order to confirm the current study's validity, the created numerical model was compared with the previous experimental and theoretical models, and the comparison results showed good agreement, and the average error is about 3%. The calculation was performed for the column flow from the power plant chimney at variable factors such as plume velocity (mass flow rate), wind speed, wind direction angles, and different fuel types (liquid and gas).The ANSYS FLUENT CFD 2020 R2 program is used to simulate numerous flow and dispersion conditions. The findings of this investigation demonstrated that the numerical model correctly predicts the column path and its concentrations. The results indicated that the concentration of pollutants in liquid fuels (crude oil) is higher than the concentration of pollutants in gaseous fuels (natural gas), where the maximum concentration of carbon dioxide (CO2) in crude oil and natural gas fuels at a ix wind speed of (2) m/s and a distance of 203 m is (0.00235, 0.0000362), respectively. It was found that the relationship between distance and concentration is an inverse relationship at different wind speeds, which means that concentration decreases with increasing distance due to the diffusion phenomenon. With increasing speed, the concentration decreases due to the diffusion speed and dilution rate. The maximum concentration of carbon dioxide at wind velocities of (2 and 10( m/s is (0.000594 and 0.000409(, respectively

Abstract During the previous years, the level of safety for potential problems in the soil was taken into account with a global safety factor because of this factor's role in overcoming all risks resulting from possible errors that may arise during tests and examinations, whether on-site or in the laboratory, there is no scientific basis on which to determine the value of the common safety factor other than the engineering experience possessed by the engineer. For most structures which are related to soil mechanics, the safety factor is suggested to be equal to (3). This value does not consider the impact of all factors affecting the properties of the soil separately. The main objective of this thesis is to provide a more efficient approaches to assessing the safety level of structure foundations, which is the probabilistic approach. In this approach, the uncertainty in soil properties, caused by potential sources of errors, is considered, and the percentage of probability of failure of a foundation is expressed (Pf). Within the framework of the probabilistic methods, two types of analysis can be distinguished. The first type is taking into account the uncertainty in the properties of the soil by considering the properties of the soil as random variables, which means taking one model to simulate the soil, and the soil in this type is a suitable material with characteristics of homogeneous. Still, in nature, the soil is a heterogeneous substance whose properties differ spatially in both horizontal and vertical directions. This ultimately leads to the necessity of representing soil properties as random fields with marginal probability functions and a self-correlation function. Within this thesis, different methods of the probabilistic approach are used to achieve the main objective of this research: i- The most powerful and accurate method, is Monte Carlo Simulation Method (MCS), is used for probabilistic analysis in simulating uncertain soil properties through random variables. ii- Subset Simulation approach (SS) is used as newest and highly efficient probabilistic method, through which effort and time are reduced compared to the Monte Carlo method, which is used to simulate uncertain soil properties through random variables that have proven their efficiency. Through the results obtained in a probabilistic analysis of a vertically loaded strip base on multilayered soil with spatially variable properties. iii- This study uses AK-MCS approach which considers the most recent and efficient probabilistic method, a combination of the Monte Carlo and Kriging methods, called the Adaptive Kriging Monte Carlo Simulation method (AKMCS), which is used to reduce computational effort and time consumption for periods. It simulated uncertain soil properties through random variables and random fields. Perform a probabilistic analysis of a vertically loaded based soil with spatially variable properties. The results obtained in this thesis showed the importance of applying the probabilistic approach to analyzing the foundations of structures instead of using the traditional method, which depends on the use of the safety factor.

Abstract The Mesopotamian marshlands are located in southern Iraq, they are the Middle East's largest wetland ecosystem, which has been suffered from drought in recent decades. AL Hammar Marsh is one of these marshes, the salty waters of The Main Outfall Drain, MOD, were suggested to be used to re-flood it. The west part of it was taken In this study as a sample of the marsh. This study attempts to find hydraulic operations of the West Part of Al Hammar Marsh based on the law of conservation of mass. Five equations were developed to find a storages area that maintains the minimum quantity of the salty concentration in the Marsh, the required values of the inflow from Al Khamissiya Canal that achieves this area, the amount of outlet flow over the required submerged area, concentration TDS within the Marsh and the concentration TDS inflow to the Marsh from Al Khamisiya Canal. Data of effecting parameters (inflow, Evapotranspiration, inflow salty concentration) have been collected for a year (2020 ). The results showed that the largest submerged Area of the Marsh was during January and December, with a value of 2678.4 Km2. During May, the lowest area was 244.8 Km2, with an average Area for the year 2020 of 1153 Km2, while the largest amount of discharge coming from Al Khamisiya Canal was during January, with the value of 35 m3/s. The value of the average discharge coming from Al Khamisiya Canal during the year was 25 m3/s. The inflow coming from Euphrates River and Al Khamisiya Canal reached 70m3/s. While the highest discharge of vi the outlet was in December of 2.683 m3/s, and the lowest was during July it reached 0.279 m3/s, While the average discharge of the outlet reached during the year is 0.993 m3/s. As for the salty concentration within the Marsh was the largest amount during November of 5506 mg/l, the lowest amount during January of 2229 mg/l. As for the salty concentration coming from Al-Khamisiya Canal reached 8050 mg/l which is the largest amount was during September, the lowest amount was 4572 mg/l during March, and the annual rate reached 6315 mg/l. To achieve the highest submerged area, the largest discharge feeders, the largest discharge from MOD, which enters the marsh through Al Khamisiya Canal, and the lowest outflow must be selected. According to the results, the largest amount of discharge from the Euphrates feeders was 87.5 m3/s in July, the largest amount of discharge from Al Khamissiya Canal was 35 m3/s in January, and the lowest discharge from the outlet was 0.279 m3/s in July. The lowest TDS concentration within the marsh occurs When the least amount of TDS is taken from AL Khamisiya Canal, which reached 4572 mg/l in March, with the lowest discharge from AL Khamisiya Canal, which was 13 m3/s in June, with the largest outflow discharge to ensure that the salts are expelled, which was 2.683 m3/s in December, and the lowest value of evapotranspiration, which was 50mm in January. As a result of this research, five equations have been obtained to calculate the hydraulic operations of the west part of Al Hammar Marsh at any time without resorting to other methods.