DIYALA JOURNAL OF ENGINEERING SCIENCES

The aim of this research is to investigate experimentally the effect of adding shear connectors to the composite deck slabs which have various geometries of steel sheeting. The behavior and resistance of composite slab is basically depending on the development of longitudinal shear resistance. In this study six specimens of composite deck slabs which have different types of geometries of steel sheets (trapezoidal, triangle and T-shapes) with dimensions (1850mm x 500mm x 110mm) were casted and tested under four-point load in presence and absence of shear connectors in order to evaluate the behavior and longitudinal shear resistance of composite slabs. The results show that the adding shear connectors to composite slabs with trapezoidal shape and triangle shape act to increase ultimate load capacity by 22.2% and 17.8% respectively as compared with composite slabs without shear connectors while effect of adding shear connectors to the composite slab with T-shape was very little or can be neglected. As well as the adding shear connectors to composite slabs with trapezoidal shape and triangle shape act to decreasing the deflection as compared with the same load also act to enhance the general performance of slabs.

Variation Orders is often a reason for construction projects exceeding projects budget and delays; it is a global problem, particularly intensive in the case of a recession of the local economy and stagnation. In Iraq, all the projects have delays in completion, and the cost affects because of the variation orders, which are not well managed. The objective of this study was to identify the key causes responsible for the variation order in construction projects in Iraq using the system dynamic. System's dynamics is the discipline of academics and rooted initially been in management and the engineering sciences. The data relating to the performance of construction projects from 27 projects adopted by Diyala University were collected. Personal interviews and questionnaires survey to the selected projects of specialized engineers were done. The results revealed that the size of variation orders in Iraqi construction projects was high, and 13 key causative factors led to variation orders. The variation in cost wasthe most influential factor effecting the construction project in Iraq. When variation orders in a cost increased, the owner's opinion decreased. When the external factors increased, cost variation orders increased. It was concluded that minimizing the variation orders was very important to realize the cost in the construction projects. Therefore, the authority management and project managers must make a plan to address these key causes in future projects to ensure their success.

Carbon steel is widely used in building industry. The different structural element might be exposed to high temperature during fire. The structural safety of steel buildings must be evaluated after they have suffered a fire. The assessment requires understanding the behaviour of carbon steel after heating.Therefore, this paper is aimed at studyingthe post-fire behaviour of carbon steel. A total of seventeen coupon specimens were tested by uniaxial tensile test. One of them was tested without heating and considered as a reference. Sixteen specimens were heated at a temperature of either 400°C or 700°C for different durations. Eight specimens were cooled in air and the others cooled in water. Heating durations were 30 min, 60 min, 90 min and 120 min. Results showed that the high-temperature has a great influence on decreasing the ultimate and yield stress and elongation for specimens cooled in the air. For specimens cooled in water, the decreased in yield and ultimate stress was minor comparing to the reference specimen. The ductility of water-cooled specimens showed a noticeable reduction comparing to specimens cooled in air. Increasing the heating time results in higher elongation for specimens heated to 400oC and lower elongation for specimens heated to 700oC, but the specimen loses strengthin both cases

Gets in the world at this time continued growth and rapid development in the whole aspects of life. The urgent needing accomplished that is in civil engineering demands like the construction of houses, schools, hospitals, roads, and other structures. Because of that and for economic and security reasons; classifying soil and knowing its bearing capacity appeared tobe very necessary conditions that offer a large domain of benefits that could not be counted. This study focused on classifying and determining the bearing capacity of some samples of soil that classified as soft soils of Baquba city the center of Diyala governorate in Iraq. Then trying to increase their bearing capacity. The California Bearing Ratio (CBR) was used in the paper to define soil strength because it is considered a force measuring parameter. Five elected physical and chemical treatments were used in predetermined percents taken from the literature and suited the kind of soil. They were quicklime, class F fly ash activated by cement, rock powder, crushed waste concrete, and crumb rubber of tires. The treatment that was the best among the five used methods was by the rock powder that improved CBR value by 570% in soil samples A used.

Pile is the form of deep foundation some time may be applying as a condition of inclined loading. There are limited experimental studies in existence on the performance of vertical piles exposed to inclined loads. In this paper, a static inclined load with four angles applied load varying (i.e., 0,15, 30, and 45 degrees) from the horizontal axis of the pile are used to the comparison of behavior for pile group as a three configurations 2x2, 2x3, and 3x2 in sandy soil. The experimental works include a soil tank and several of tools used to achieve the objective of this study. It can be seen that the pile group is influenced by the angle of inclination of applying load, furthermore the results displays that the increase in spacing between pile cause decrease lateral movement under the similar angle of inclination of load applied. The performing of each models better-quality using S/D=7, this is attributable to reduce the interface of pile-soil-pile for the group. Groups 2x3 showing resistance and have bearing capacity to the lateral displacement from other groups about 40% for group 2x2 and about 50% for group 3x2

Construction projects are of a special nature affected by many factors, which makes them exposed to multiple risks that may lead to the abandonment of projects. Recently, the Iraqi construction sector is facing a number of problems. Abandoned construction projects are one of the most common and dangerous problems in the construction industry in Iraq, with their negative effects on stakeholders, the economy, and the environment due tothe lack of sufficient financial and administrative capabilities to complete construction projects, which is reflected in exceeding the time limit for the completion of projects. The aim of this research is to use the analytic network process (ANP) technique to choose the best form of Public-Private Partnership (PPP) contracts to fund abandoned projects in Iraq. using a questionnaire survey to determine the most criteria and alternatives for selecting appropriate financing for the abandoned project. The results shown final weight of the Build-Own-Operate (BOO) contract from ANP is 0.533, which is the best form of PPP contract among the alternatives proposed to fund the project

Design structures to resist natural hazards is a vital issue to mitigate the impact of such threats. Earthquakes could lead to numerous injuries and infrastructure destruction. Specifically,when structures are not designed to resist seismic load. This article presents dynamic analysis of four-story shear frame under moderate ground motion to determine the dynamic response. The proposed location of the considered frame is near Iraq-Iran border due to increase of seismic activities in last years. Structures in the considered seismic zone are essentially either residential or commercial buildings and not designed to resist seismic load, therefore structural system failure is probable. Simplified model is considered to determine response spectrum according to the International Building Code requirements. The algorithm of the analysis is developed using MATLAB®code to get mode shapes, response spectrum acceleration, maximum displacement, maximum shear forces, and modal participation mass at each story. The article develops design response spectra curve of Erbil city. Furthermore, the analysis results showed that first mode shape has more contribution than the other modes because higher percentage of the mass of the shear frame responds to the ground motion, and 88.53% of shear-frame mass is participating responds to the ground motion in the same mode

The phenomenon of liquefaction is one of the most important problems in engineering projects. It occurs in saturated sandy soils during the occurrence of earthquakes. Methods based on the standard penetration test (SPT) were developed to calculate the liquefaction potential according to the seismic loads. These methods have been developed and updated over time by some researchers. This paper analyses the comparison between methods of calculating liquefaction potential. The case study that was selected for the analysis of the comparison methods is Diyala Governorate soil. The methods that have been chosen for making a comparative analysis are the Japanese method, National Centre for Earthquake Engineering Research 1997 (NCEER) workshop, Task Force Report 2007 (Vancouver) and Boulanger and Idriss 2014. The analysis of results stated that the Boulanger and Idriss method is considered more suitable than others for calculating the potential for liquefaction in Diyala Governorate soil. It is found that the Boulanger and Idriss method has higher safety factor than the two methods (80.7% from Vancouver and 38.8% from the NCEER workshop) and less than the Japanese method.

Construction projects in Iraq face many dangers that cause exceeding the estimated cost of the project and not completing the project on time, and since the risk management process in construction projects is of great importance in controlling and reducing the impact of risks in construction projects, so it is necessary to identify these risks and evaluate them correctly in order to increase accuracy and the health of the subsequent stages of the risk management process in construction projects. This paper aims to identify the most important risks in construction projects in Iraq and to conduct a qualitative assessment of the identified risks and arrange them according to their importance. The researcheradopted the questionnaire method as a tool to determine the risks and used the technique of probability and effect matrix to conduct the qualitative assessment of the identified risks. The study found that there are 48 risk factors that constitute the most dangerous factor in construction projects in Iraq, and 9 of the determining factors were within the high level of risk, and at the forefront of which was the inability of the owner to finance the project

The existing buildings can be improved under the seismic effect by adding rubber to the bolts in the connection.The buildings when maintenance work is happening there is a problem many times and it should be evacuated and requires high cost.This study aims to maintain the building without having to remove it and at a very low cost compared to other methods.This study includes six models divided into two groups. The two groups differ in terms of the number of bolts in the contact area between the column and the beam in the steel frame.The first group models contain four bolts in the connection area and the second group forms contain five bolts in the contact area.Each group includes three models representing the first form of a reference model that has not rubber material around the bolts in the connection area, the second model contains 150% rubber than a bolt diameter around one bolt of the connection area, and all the boltsin the connection area in the third model are warped with rubber.The presence of rubber around one boltgave a load, displacement, drifting, damping ratio, ductility index energy dissipation close to models where all contact boltsare warpedwith rubber material.

n personal image recognition algorithms, two effective factors govern the system's evaluation, recognition rate and size of the database. Unfortunately, the recognition rate proportional to the increase in training sets. Consequently, that increases the processing time and memory limitation problems. This paper's main goal was to presenta robust algorithm with minimum data sets and a high recognition rate. Images for ten persons were chosen as a database, nine images for each individual as the full version of the training data set, and one image for each person out of the training set asa test pattern before the database reduction procedure. The proposed algorithm integrates Principal Component Analysis (PCA) as a feature extraction technique with the minimum means of clusters and Euclidean Distance to achieve personal recognition. Afterindexing the training set for each person, the clustering of the differences is determined. The recognition of the person represented by the minimum mean index; this process returned with each reduction. The experimental results show that the recognition rate is 100% despite reducing the training sets to 44%, while the recognition rate decrease to 70% when the reduction reaches 89%. The clear picture out is the results of the proposed system reduces the training sets in addition to obtaining a high recognition rate.

The aim of this paper was to review the mechanism of the expansive soil-lime reactions: short term and long-term reactions in both lime modification and lime stabilization. The focus of the study was the effect of curing time for a certain centigrade 25C curing temperature in both lime modification / stabilization-expansive soils on the coefficient of permeability. Peer reviewed articles published between 2000-and 2019 were collected and relevant data were extracted. Results of this review study showed that the coefficient of permeability of expansive soils modified with lime increased during the first 7 days of curing time at curing temperature 25C and it remains constant or slightly decreased for longer curing time periods. However, for expansive soils stabilized with lime, it was found that the coefficient of permeability increased during the first 7-day curing time at curing temperature 25C, then decreased during the longer curing time periods (pozzolanic reaction). It is also noted that even though the coefficient of permeability decreased during pozzolanic reaction, it remains higher than that of the untreated soils