This study computationally investigates to examine the impacts of repeated loading on L-shaped spandrel beams made of reinforced concrete, which were strengthened by externally bonded carbon fiber reinforced plastic sheets. The object of the research is to evaluate the following three aspects of structural behavior: degradation of reaction forces, evolution of inertia forces, and residual performance. Ayad and Oukaili's experimental impact-loading program, which featured midspan drop-weight loading on RC spandrel beams before and after strengthening, was used to validate a comprehensive three-dimensional finite element model created in ABAQUS. A sequence of 25 impacts before and 25 impacts after CFRP application was simulated to trace impact force, reaction force, inertia force, midspan deflection, and damage progression. Because of cumulative stiffness deterioration, the peak impact force in the unstrengthened beams reduced by 45%, the reaction force decreased by 54.7–57.3%, and the inertia force increased by 237.5–1090%. The peak impact force decline was limited to 31.8% with CFRP strengthening, whereas the reaction force reduction varied from 36.9% to 39%. In comparison to the much greater amplification seen prior to strengthening, the rise in inertia forces was also much reduced, staying between 114.6 and 122.2%. Additionally, there was a 19.2–23.2% decrease in the midspan deflection at the 25th impact. After 25 impacts, CFRP-strengthened beams maintained 68.3–70% of their initial capacity, but unstrengthened beams only maintained 56.2–60.1%, according to the residual performance index (RPI), which showed a notable improvement. Concrete had saturated tensile cracking prior to strengthening, according to damage analysis, but matrix microcracking (HSNMTCRT) without fiber tensile damage (DAMAGEFT) dominated post-retrofit behavior, indicating the efficient confinement and energy-dissipating function of CFRP. These results extend the previous experimental interpretation by quantifying repeated-impact trends in reaction and inertia forces, and show that externally bonded CFRP sheets improve the service-life performance of reinforced concrete ledged beams by enhancing stiffness retention, energy dissipation, inertial stability, and damage control.
Although the axial aptitude and pile load transfer under static loading have been extensively documented, the dynamic axial reaction, on the other hand, requires further investigation. During a seismic event, the pile load applied may increase, while the soil load carrying capacity may decrease due to the shaking, resulting in additional settlement. The researchers concentrated their efforts on determining the cause of extensive damage to the piles after the seismic event. Such failures were linked to discontinuities in the subsoil due to abrupt differences in soil stiffness, and so actions were called kinematic impact of the earthquake on piles depending on the outcomes of laboratory
The theoretical analysis depends on the Classical Laminated Plate Theory (CLPT) that is based on the Von-K ráman Theory and Kirchhov Hypothesis in the deflection analysis during elastic limit as well as the Hooke's laws of calculation the stresses. New function for boundary condition is used to solve the forth degree of differential equations which depends on variety sources of advanced engineering mathematics. The behavior of composite laminated plates, symmetric and anti-symmetric of cross-ply angle, under out-of-plane loads (uniform distributed loads) with two different boundary conditions are investigated to obtain the central deflection for mid-plane by using the Ritz method. The computer programs is built using Ma
... Show MoreThis work investigates the effect of earthquakes on the stability of a collective pile subjected to seismic loads in the soil layer. Plaxis 3D 2020 finite element software modeled pile behavior in dry soils with sloping layers. The results showed a remarkable fluctuation between the earthquakes, where the three earthquakes (Halabja, El Centro, and Kobe) and the acceleration peak in the Kobe earthquake had a time of about 11 seconds. Different settlement results were shown, as different values were recorded for the three types of earthquakes. Settlement ratios were increased by increasing the seismic intensity; hence the maximum settlement was observed with the model under the effect of the Kobe earthquake (0.58 g), where
... Show MoreThe research aims at considering the reality of cognitive bias and organizational inertia as determinants of strategic change in a sample of companies listed in Amman Stock Market. To achieve objectives of the research, a model consisting of two independent variables has been designed, namely:
(1) The cognitive bias resulting from (escalating commitment, analogy, previous assumptions, representative generalization, command and control, convergent thinking), and (2) Organizational inertia due to (Icarus discrepancy, power distribution, rooted organizational culture), and a dependent variable, strategic change in (leadership patterns, strategy, the organization per se).
From the model two main hypotheses were derived;
... Show MoreIn earthquake engineering problems, uncertainty exists not only in the seismic excitations but also in the structure's parameters. This study investigates the influence of structural geometry, elastic modulus, mass density, and section dimension uncertainty on the stochastic earthquake response of a multi-story moment resisting frame subjected to random ground motion. The North-south component of the Ali Gharbi earthquake in 2012, Iraq, is selected as ground excitation. Using the power spectral density function (PSD), the two-dimensional finite element model of the moment resisting frame's base motion is modified to account for random ground motion. The probabilistic study of the moment resisting frame structure using stochastic fin
... Show MoreIn this study, the behavior of screw piles models with continuous helix was studied by conducting laboratory experimental tests on a single screw pile that has several aspect ratios (L/D) under the influence of static axial compression loads. The screw piles were inserted in a soft soil that has a unit weight of 18.72 kN/m3 and moisture content of 30.19%. Also, the soil has a liquid limit of 55% and a plasticity index of 32%. A physical laboratory model was designed to investigate the ultimate compression capacity of the screw pile and measure the generated porewater pressure during the loading process. The bedding soil was prepared according to the field unit weight and moisture content and the failure load was assumed correspondin
... Show MoreThin-walled members are increasingly used in structural applications, especially in light structures like in constructions and aircraft structures because of their high strength-to-weight ratio. Perforations are often made on these structures for reducing weight and to facilitate the services and maintenance works like in aircraft wing ribs. This type of structures suffers from buckling phenomena due to its dimensions, and this suffering increases with the presence of holes in it. This study investigated experimentally and numerically the buckling behavior of aluminum alloy 6061-O thin-walled lipped channel beam with specific holes subjected to compression load. A nonlinear finite elements analysis was used to obtain the
... Show MoreThe purpose of this study is to examine the experimental, numerical, and analytical behavior of a novel class of composite columns. These columns are designed to replace conventional deformed steel bars with small circular steel tubes filled with cementitious grouting material in a longitudinal orientation. Twelve concrete columns in all were assembled and tested under various loading scenarios. These columns were evaluated under concentric compression load, two eccentric compression loads (25 or 50 mm), and flexural load. They included various forms of reinforcement in a longitudinal direction, including steel bars or tubes. A developed three‐dimensional finite element analysi