SOIL-STRUCTURE INTERACTION OF FRP PILES IN INTEGRAL ABUTMENT BRIDGES

The rapid degradation of conventional material piling is one of the major problems in the bridge and civil infrastructure industry. Conventional construction materials have major disadvantages that increase their maintenance cost and reduce their service life especially in aggressive environments. The use of advanced composite materials such as Fiber Reinforced Polymers (FRPs) offers a better alternative to conventional building materials in terms of strength, weight, durability, and life cycle cost. Integral abutment bridges are a special type of bridges that are built without bearings or expansion joints. These bridges are usually subjected to cycles of expansion and contraction that causes horizontal movements of the pile foundations. Accommodating such movements requires some flexibility in the piling system. Fiber reinforced composites (FRPs) have the strength and flexibility and can be custom designed as needed. An extensive literature and market survey indicated that composite materials are increasingly being considered for use in civil infrastructure applications ranging from the retrofit and rehabilitation of buildings and bridges to the construction of new structural systems. Very little research has been conducted on FRPs as piling materials. The current research investigates the use of fiber reinforced composites as piling materials for jointless bridges. Three-dimensional finite element models were developed and analyzed using the multi purpose FEM package ANSYS. The models were built to take into consideration multiple design parameters including the non-linear behavior of soil and concrete and the orthotropic behavior of unidirectional composites. Investigation results showed that FRP composites are good candidates for use in piling systems. Because of their flexibility in both geometrical shaping and layer lay-up, FRPs provide more options to designers to come up with suitable systems based on their needs. A new pile section is introduced to be used with or without concrete filling. The section consists of two flanges and a double web to allow flexibility in controlling the size of concrete filling between the webs. Analysis results showed that flexibility of the geometry of the new pile section and the flexibility of tailoring multi-layered unidirectional FRP composites make the pile customizable for best performance. FRP composites lend themselves to be optimized to achieve desired properties. The study showed that favorable stiffness and stress results can be obtained for composite piles in integral abutment bridges by optimizing the section's geometry while keeping a fixed cross-sectional area

Plastic shrinkage cracking and bleeding of concrete prepared with alkali activated cement

Restrained shrinkage cracking that appears on concrete surfaces during construction, or while concrete in the curing process adversely affect the long-term durability and other performance attributes of concrete-based-infrastructures. This study investigates the effects of early-age surface cracking on restrained shrinkage concrete made of alkali activated cement. Concrete produced using this class of cement differs from ordinary Portland cement concrete in terms of surface qualities and some other properties. Bleeding which could be a main cause of plastic shrinkage cracking was measured and compared with that of Portland cement. Rheological tests were performed to gain further insight into factors that may influence the early-age performance of the cement paste. Portland cement was used as control for comparative assessment of the alkali activated cement performance. Experimental test showed that alkali activated cement improved the characteristics of the newly produced concrete. The concrete prepared using alkali activated cement has low tendency to bleeding and higher resistance to plastic shrinkage, also, the viscosity and yield stress of the alkali activated cement paste were relatively higher when compared to those of ordinary Portland cement paste. Test data collected from rheological and bleeding tests on the alkali activated cement concrete were used to explain its desired resistance to plastic shrinkage cracking

Molecular Characterization of Staphylococcus aureus Isolated from Meat and Their Antibiotic Resistance Profiles

The aims of this study were to characterize S. aureus isolates from different meat sources in Jordan and study their genetic relationship using PCR-RFLP in addition to their antibiotic resistance profiles. Thirty S. aureus isolates were identified and confirmed by PCR techniques. The isolates from goat and camel meats were sensitive to the majority of the tested antibiotics. Plasmid profiling revealed that 26 isolates contained at least one plasmid with no correlation between the number of plasmids and the resistance profiles. PCR-RFLP of the coagulase gene (coa) classified the isolates to several clusters upon digestion with Alu I or Cfo I restriction enzymes. This study concluded that the 30 S. aureus isolates were genetically diverse and comprised heterogeneous population with 7 genotypes at both 33.1 and 51.2 similarity levels

The Internet of Energy: Smart Sensor Networks and Big Data Management for Smart Grid

Smart sensor networks provide numerous opportunities for smart grid applications including power monitoring, demand-side energy management, coordination of distributed storage, and integration of renewable energy generators. Because of their low cost and ease-of-deployment, smart sensor networks are likely to be used on a large scale in future of smart power grids. The result is a huge volume of different variety of data sets. Processing and analyzing these data reveals deeper insights that can help expert to improve the operation of power grid to achieve better performance. The technology to collect massive amounts of data is available today, but managing the data efficiently and extracting the most useful information out of it remains a challenge. This paper discusses and provides recommendations and practices to be used in the future of smart grid and Internet of things. We explore the different applications of smart sensor networks in the domain of smart power grid. Also we discuss the techniques used to manage big data generated by sensors and meters for application processing.Published versio

Using Social Media Network by Special Education Teachers

This study aimed at identifying the use of the social media network (Facebook) and its relationship to psychological compatibility of special education teachers by answering four questions that include all the variables of the current study. The study used the descriptive approach and developed a scale to reveal the relationship of Facebook use and psychological compatibility. The psychological scale was applied to a random sample of special education teachers (n=520), who constitute 18% from the study population in Aseer region. The results of the study showed that the period that special education teachers spend using Facebook that received the highest frequency was less than two hours per day. The results revealed that the level of psychological compatibility among special education teachers, who use Facebook was high. There was a negative relationship between the period that special education teachers spend using Facebook and the level of psychological compatibility. The results also indicated that there were no statistically significant differences attributed to the effect of gender on the period of use of Facebook among special education teachers