In this paper, a practical method of analysis of the pile displacements is proposed on the basis of the theory of load-transfer curves widely used in pile design and analysis. The parameters of the load-transfer curves for piles under axial load (called t-z, q-z curves) or lateral load (called P-Y curves) were correlated with the number of blows Nspt measured during the standard penetration test (SPT). Well documented case histories of full-scale axial or lateral loading tests on single piles in sand were collected, and the analysis of the experimental results led to define the parameters of the load-transfer curves. Two practical methods of computation of a single pile under an axial load or a lateral load were proposed to be used within the scope of a pile foundation project. At last, a validation process of the load-transfer curves was undertaken by direct comparison of the predicted pile displacements to those measured during other pile loading tests, which showed a good predictive capability of the two proposed methods
Abstract The purpose of highway geometric design is to provide safe and economical highways. One of the utmost important geometric design element for safely travel that should be satisfied is visibility on designed road. This can achieved by providing adequate sight distance in both horizontal and vertical alignments. Minimum sight distance that should be provided at all points along highway is stopping sight distance SSD. In the design of vertical curves AASHTO's Geometric design Policy uses the sight distance requirement as a major criterion in curve length determination. Moreover, sight distance has great effect on highway constructional cost because more required sight distance means more vertical curve length, which in turn means more earthwork materials. Consequently, safety and economics can be considered as a major criterion in design of highways. The AASHTO's model involved design speed, perception-reaction time, and frication factor as a parameters used for SSD computations on level sections. On inclined surfaces, an additional parameter denoted by (G), which reflect grade of sloped surface on SSD. In the present paper a new approximate methodology and Equations are formulated though which a suitable design grade value can be estimated on vertical curves where the grade not constant then utilizing this value to compute SSD on these curves and hence compute vertical curve length corrected for grade effect. Generalization of present methodology is carried out by derivation a general mathematical solution. From these derivations it has been found that the suitable grade value for Type I and Type III (initial and final grade are descending and ascending) is half of the largest grade among G1 and G2. While the design grade value is the average value of G1 and G2 for Type II and Type IV (both grade are descending or ascending). Comparison with other grade estimation on vertical curves suggestions showed that the present methodology produces more reasonable and economical value because the obtained length is no longer to be uneconomical as compared with other suggestions. At the same time it provides a safe value used in all design cases those reflects the actual case as compared with other suggestions those ignored or reduced the effect of grade.
The purpose of this paper is to investigate the relationship between the Ultrasonic Pulse Velocity (UPV) and the compressive strength and the flexural strength of hardened concrete when subjected to different concentrations of sulfate attacks. The specimens used in the studies were made of concrete with different water-cement ratios (w/c). The UPV measurement and compressive and flexural strengths tests were carried out for concrete specimens of ages (4-40) days. The experimental results show that the relationship between UPV and the compressive and the flexural strengths of concrete is significantly influenced by age and the concentration of sulfate attack. The UPV and the compressive strength of concrete grow with age, but the growth rate varies with w/c ratio. It is found that with the same concentration of sulfate attack, a clear relationship curve can be drawn to describe the UPV and compressive and flexural strengths of hardened concrete. This paper presents the UPV-strength relationship curves for concrete having different (w/c) ratios subjected to different concentrations of sulfate attack. These curves are thought to be suitable for prediction of hardened concrete strength with a measured UPV value when sulfate attack is considered. It is concluded that the UPV increases with the increase of the compressive and flexural strength. The observed range for UPV was (3.5 to 4.75 km/sec) corresponds to (24 to 28.5 N/mm2) for compressive strength and to (4.6 to 6.5 N/mm2) for flexural strength. The UPV decreases with the increase of the concentration of sulfate exposure. The obtained maximum reduction in UPV was 31.6% with respect to the control spacemen at age of 40 days.
AbstractSemi-empirical equation for water flow through packed bed of sphere particles of mono size packing system has been estimated depending on Buckingham theorem. Different parameters affecting the pressure drop of fluid flow through packed bed have been studied. These parameters are fluid velocity, bed porosity, bed diameter, sphericity, particle diameter, packing height and wall effect. Several types and kinds of packing materials have been used in this study such as (Pea Gravel, Marbles, Glass Marbles, Black Marbles, Clear Marbles, Acrylic balls and Glass spheres). The diameters of the packing materials used in this model are from the range of (0.2-8.89) cm, the porosity is from the range of (0.3-0.47), the bed diameters is from the range of (7.62 - 15.24) cm and the height of packing is from the range of (26.03 - 55.88) cm. πThe results of all calculations for the estimated equations have been compared with many documented experimental literatures. This comparison gave a very good agreement, and has been represented in curves. The results from Ergun equation using similar conditions have been represented in the curves for the sake of comparison.
Very little attention was given to study learning curves phenomenon in the construction industry, for many reasons related to the nature of production in this industry and also because of the variety of factors which affect these works. This research aims to measure the amount of improvement in the acquired production by the workers on the repeated construction operation because of the experience and learning in Iraq compared with a neighboring country (Syria).The measurement technique involves recording the time required to achieve every unit and finding out the mathematical relation which represents the learning curve for each item of production. The study involves six items (activities) of construction as follows: 1- Ceramic tiles (20 × 20 cm) for walls. 2- Paving the pavement of the street with concrete blocks. 3- Tiling the rooms with mosaic (30 × 30 cm). 4- Building the walls with concrete blocks (20 × 20 × 40 cm). 5- Coating the walls with emulsion paints. 6- Finishing the walls with gypsum The most important results of the research are that the amount of learning varies from 4.2% to 8.6% in Iraq, and 3.3% to 11.8% in Syria, which considered little compared to the developed countries.
The first step toward urban transportation planning is to make a data base then to initiate the first mathematical model known as trip generation model which this study adopts. The study area in the waste sector of Ramadi city (Al-Tameem, 5 km) is considered as one sector consists of eight zones containing about 11640 dwelling units. Home interview survey was made of random sample which represent 5% of the study area population. The collected information was concerned with structure, vehicles, families and each person living in the dwelling unit. The total person’s trips per dwelling unit and various purposes were investigated. All data was programmed for analysis by spss program, which took place firstly by multiple linear regression to obtain the primarily models. After series of analysis and trials, the most significant independent variables were identified as family size and car ownership. Also, the final equations for producing trips were obtained. They were reasonable, more practical and carrying the best statistical measures. Set of curves were developed to put the sub models in any easy and more desirable manner for wide application and forecasting.
In this study, the structural behaviour of RC-deep beams of glass fibre-reinforced polymer (GFRP) rubberized concrete is investigated. Rubberized concrete is manufactured by replacing fine sand aggregate with rubber crumbs in volumetric replacement ratios. The main variables were the crumb rubber content (0%, 10%, and 20%) and the main reinforcement ratio. Tested Six samples of deep beams with different dimensions (b = 150, h = 300 mm, L= 1400 mm) were under a four-point load until failure. The parameters under investigation were the mechanical properties of mixtures, load-midspan deflection curves, toughness, and the load-strain relationship. The results indicate that the increased crumb rubber content led to a decrease in the mechanical properties of rubberized concrete mixtures. It was found that the behaviour of all samples of rubberized concrete affected the deflection load curve, the ultimate load, and the increase in deflection. The sample R2-10% Rub showed the highest toughness among the tested samples, with an increase of 301.6% compared to the reference.
ABSTRACT: In this study an attempt is made to develop a method of analysis dealing with a multi-layer composite beam, for linear material and shear connector behavior in which the slip (horizontal displacement) and uplift force (vertical displacement) are taken into consideration. The analysis is based on a approach presented by Roberts[1], which takes into consideration horizontal and vertical displacement in interfaces. The analysis led to a set of eight differential equations contains derivatives of the fourth and third order. A program based on the present analysis is built. Series of three push-out tests were carried out to investigate the capacity of shear stiffness for connectors. From these tests, load-slip curves were obtained. Also, series of multi-layer composite simply supported beams were tested. Each one consists of three layers in different material properties and dimensions. A comparison between the experimental values and numerical analysis is carried out. Close agreement is obtained with experimental values for different materials, layers thickness and shear stiffness.
One of the most popular non- destructive techniques is ultrasonic pulse velocity (UPV) which used in assessment of concrete properties. A statistical experimental program was carried out in the present study to establish an accurate relation between the UPV and the concrete compressive strength. The program involved testing of concrete cubes cast with specified test variables. The variables are the age and density of concrete. In this research, all the samples were tested by direct ultrasonic pulse velocity (DUPV) and surface ultrasonic pulse velocity (SUPV) to measure the wave velocity in concrete and the compressive strength for each sample. An experimental study was conducted to compare between the velocities of ultrasonic waves that transmitted along the two paths; direct and indirect. A total of more than 150 cubes having dimensions of 150 mm side were prepared to conduct both non-destructive and the compressive strength (destructive testing). The results from experimental program were used as input data in a statistical program (SPSS) to predict the best equation, which can represent the relation between the UPV (direct, indirect), and compressive strength, a linear equation is proposed for this purpose. The UPV measurement and compressive strength tests were carried out at the concrete age of 7, 28, 56 days. A relationship curves were drawn between DUPV, SUPV, compressive strength and density. The mixes composition in this study consists of ordinary Portland cement, fine sand, gravel, super-plasticizer, and water. All the specimens were under (20) Cº. The statistical analysis revealed that the possibility in evaluating the properties of the concrete by using direct and indirect wave velocities