In this paper, fire resistance and residual capacity tests were carried out on encased pultruded glass fiber-reinforced polymer (GFRP) I-beams with high-strength concrete beams. The specimens were loaded concurrently under 25% of the ultimate load and fire exposure (an increase in temperature of 700 °C) for 70 min. Subsequently, the fire-damaged specimens were allowed to cool and then were loaded statically until failure to explore the residual behaviors. The effects of using shear connectors and web stiffeners on the residual behavior were investigated. Finite Element (FE) analysis was developed to simulate the encased pultruded GFRP I-beams under the effect of fire loading. The thermal analyses were performed using the general-purpose FE ABAQUS package. This simulation considered the material and geometric nonlinearities and the effect of temperature on the constitutive models of materials. The FE results showed good agreement with the experimental data. The residual peak load and the corresponding mid-span deflection obtained were 5% and 4% higher than those of the experimental results. The validated FE model was utilized to explore the influence of the tensile strength of GFRP and concrete compressive strength on the post-fire flexural behavior of the encased GFRP I-beams. The encased GFRP beams kept higher residual peak loads. Moreover, the encased GFRP beam with shear connectors (EGS-F), encased GFRP beam with web stiffeners (EGW-F), and encased GFRP beam with shear connectors and web stiffeners (EGSW-F) exhibited higher residual peak loads due to the presence of shear connectors and web stiffeners. However, the web stiffeners showed a minor enhancement in the peak load.
Objective(s): The present study aims at identifying the Iraqi Colleges of Nursing Deans' leadership
behaviors effectiveness and faculty members' motivation towards work in these colleges.
Methodology: Descriptive design has been used for the sample survey manner, which is the
appropriate approach to the study of social phenomena in the field where provides data on the reality of
these phenomena and relations between the causes and consequences and an analysis of it and perhaps
the factors affecting it and how it appears. The study relies on a questionnaire to collect data from the
participants which is composed of (86) items distributed on three axes: First, the demographic
characteristics which are composed of (8) i
Some structures such as tall buildings, offshore platforms, and bridge bents are subjected to lateral loads of considerable magnitude due to wind and wave actions, ship impacts, or high-speed vehicles. Significant torsional forces can be transferred to the foundation piles by virtue of eccentric lateral loading. The testing program of this study includes one group consists of 3 piles, four percentages of allowable vertical load were used (0%, 25%, 50%, and 100%) with two L/D ratios 20 and 30, vertical allowable load 110 N for L/D = 20 and 156 N for L/D = 30. The results obtained indicate that the torsional capacity for pile group increases with increasing the percentage of allowable vertical load, when the percentage of allowable vertica
... Show MoreGypseous soils are considered one of the most problematic soils. The skirted foundation is an alternative technology that works to improve the bearing capacity and reduce settlement. This paper investigates the use of square skirted foundations resting on gypseous soil subjected to concentric and eccentric vertical load with eccentricity values of 4, 8, and 17 mm in 16 experimental model tests. To obtain the results by using this type of foundation, a small-scale physical model was designed to obtain the load–settlement behavior of the square skirted foundation; the dimension of the square footing is 100 mm × 100 mm with 1 mm thickness, the skirt depth (
Autorías: Muwafaq Obayes Khudhair, Hayder Talib Jasim, Ahmed Thare Hani. Localización: Revista iberoamericana de psicología del ejercicio y el deporte. Nº. 6, 2022. Artículo de Revista en Dialnet.
In this work, mesoporous silica SBA-15 was prepared and functionalized with amine groups (i.e., NH2) to form NH2/SBA-15. The curcumin (CUR) was encapsulated into the surface and pore of NH2/SBA-15 to create CUR@NH2/SBA-15 as an efficient carrier in drug delivery systems (DDSs). The three samples (i.e., SBA-15, NH2/SBA-15, and CUR@NH2/SBA-15) were characterized. The study investigated the effect of the carrier dose, initial CUR concentration, pH, and contact time on the CUR loading efficiency (DLE%) via adsorption. The best DLE% for the SBA-15 and NH2/SBA-15 were found to be 45% and 89.7%, respectively. The Langmuir isotherm had a greater correlation coefficient (R2) of 0.998 for SBA-15. A pseudo-secondorder kinetic model seemed to fit well
... Show MoreThe Dynamic Load Factor (DLF) is defined as the ratio between the maximum dynamic and static responses in terms of stress, strain, deflection, reaction, etc. DLF adopted by different design codes is based on parameters such as bridge span length, traffic load models, and bridge natural frequency. During the last decades, a lot of researches have been made to study the DLF of simply supported bridges due to vehicle loading. On the other hand, fewer works have been reported on continuous bridges especially with skew supports. This paper focuses on the investigation of the DLF for a highly skewed steel I-girder bridge, namely the US13 Bridge in Delaware State, USA. Field testing under various load passes of a weighed load vehicle was u
... Show MoreTo enhance the structural performance of concrete-filled steel tube (CFST) columns, various strengthening techniques have been proposed, including the use of internal steel stiffeners, external wrapping with carbon fiber-reinforced polymer (CFRP) sheets, and embedded steel elements. However, the behavior of concrete-filled stainless-steel tube (CFSST) columns remains insufficiently explored. This study numerically investigates the axial performance of square CFSST columns internally strengthened with embedded I-section steel profiles under biaxial eccentric loading. Finite element (FE) simulations were conducted using ABAQUS v. 6.2, and the developed models were validated against experimental results from the literature. A comprehen
... Show MoreIn most Reinforced Concrete (RC) buildings, the cross-section size of rectangular columns that conventionally used in these structures is larger than the thickness of their partitions. Consequently, a part of the column is protruded out of the wall which has some architectural disadvantages. Reducing the column size by using high strength concrete will result in slender column, thus the stability problem may be occurred. The stability problem is difficult to be overcome with rectangular columns. This paper study the effectiveness of using new types of columns called Specially Shaped Reinforced Concrete (SSRC) columns. Besides, the use of SSRC columns provides many structural advantage
This paper presents theoretical parametric study of the curvature ductility capacity for reinforced concrete column sections. The study considers the behavior of concrete and reinforcing steel under different strain rates. A computer program has been written to compute the curvature ductility taking into account the spalling in concrete cover. Strain rate sensitive constitutive models of steel and concrete were used for predicting the moment-curvature relationship of reinforced concrete columns at different rate of straining. The study parameters are the yield strength of main reinforcement, yield strength of transverse reinforcement, compressive strength of concrete, spacing of ties and the axial load. The results indicated that hi
... Show More