Two-layered Grouted Aggregates Fibrous Concrete Composite (TGAFCC) is a new category concrete which became popular recently and attracted the attention of researchers globally. Recent studies indicated that TGAFCC has notable improvement in mechanical properties, which has been sufficiently documented. However, the impact behaviour of TGAFCC when combined with Glass Fibre Mesh (GFM) and Textile Fibre Mesh (TFM) is still unexplored. The research objective is to study the effect of GFM and TFM inser- tion in TGAFCC against the drop hammer impact. Twenty one TGAFCC mixtures were prepared and divided into two series; non-fibrous concrete and fibrous concrete. The combined action of GFM and TFM of various diameters were inserted between the two layers and tested experimentally against drop mass impact. Additionally, all fibrous specimens were reinforced with a constant 3% dosage of 5D hooked end fibre. All specimens were tested under repeated drop mass impact as per ACI Committee 544. The impacts number or number of blows till the first visible crack and failure, impact energy at the first vis- ible crack and failure, impact ductility index and cracking configuration were examined. Besides, Weibull distribution was used to examine the variations in the test results, where impact numbers were pre- sented using the reliability function. The research findings indicate that inserting GFM and TFM between the two layers combined with 5D hooked end steel fibres, provided high impact resistance, higher absorbed energy and prolonged failure duration. Increasing the diameters of the GFM and TFM insertions, in both non-fibrous and fibrous concrete resulted in increasing the impact numbers till the first visible crack and failure. The experimental findings confirm that the major contribution of impact resistance comes from the 5D hooked end steel fibres, while the share of the intermediate meshes was significantly lower. arabic 13 English 88
Hakim S. Abdelgader (12-2020)

Abstract Steel joints are the main part a steel structure. The steel members come together in a joint, to where the load action will be transferred between them.These members are with different section properties, may be joined with different type of connections welds, bolts or rivets. The level of fixity is also important which varies from flexible, semi-rigid to fixed. There is also an important factor of joint behavior, the type of loading (tension, shear, bending and torsion). For these the mentioned different factors that affects the behavior of a joint very complicated to demonstrate exactly.The design procedure according to the well known specification is generally based on experimental studies.The present study tries to throw light on some factors affecting the strength consideration for designing beam to columnconnection because of its importance in steel structures from point of view of uses.
علي عبدالله الجعط (2008)

Download PDF Research Article - Civil EngineeringPublished: 31 July 2019Investigation on Mode I Fracture Behavior of Hybrid Fiber-Reinforced Geopolymer CompositesNeha P. Asrani, G. Murali, […]K. Karthikeyan  Arabian Journal for Science and Engineering volume 44, pages8545–8555(2019)Cite this article 225 Accesses 4 Citations Metricsdetails Abstract Recent reports in the literature have shown that fiber-reinforced geopolymer composites (FRGC) made with monofibers exhibit a significant enhancement in fracture energy. However, many aspects of the fracture performance of hybrid fiber-reinforced geopolymer composites (HFRGC) remain largely unexploited, and these are predominant for the structures. For the first time, the mode I fracture energy of HFRGC is investigated. The mode I behavior was assessed using pre-notched beams in accordance with the RILEM three-point bending test. Five different HFRGC mixtures were prepared using three fiber types: steel, polypropylene and glass (SF, PF and GF). The parameters of the pre-notched beam in flexure tested in this study were the first crack and peak load, crack mouth opening displacement at the first crack load and peak load, equivalent tensile strength, post-peak slope, reinforcing index, residual tensile strength and fracture energy. The results reveal that there is a positive interaction amidst the fibers in geopolymer composites that leads to an enhancement in the mode I fracture energy compared to the reference specimen. This study probes the influence of novel HFRGC while producing high-quality concrete, which can then be leveraged for sustainable infrastructure and various civil engineering works. arabic 15 English 79
Hakim Salem Abdelgader Abdelgader (7-2019)