This study presents an innovative hybrid profiled steel- and fiber-reinforced polymer (FRP) reinforced concrete (HPSFRC) structural system that primarily consists of thin semiclosed T-shaped cold-formed steel sheeting that is externally enclosed with an FRP sheet and filled with concrete. The experimental study was conducted in two interdependent parts: a development study and a validation study. In the development study, six specimens were tested to determine the best interlocking technique between the concrete flange and the other components of the cross section. In addition, two specimens were examined to define the shear strength of the steel-concrete composite profiled system. The validation study presented the flexural behaviors of HPSFRC T-beams with different reinforcement configurations. The test results of the HPSFRC beams were assessed in terms of the behavior of a conventional reinforced concrete T-beam and a composite profiled T-beam. The HPSFRC T-beams achieved a ductility comparable to that of a composite profiled beam but exhibited a higher flexural strength. The flexural behaviors of the HPSFRC beams can be controlled using additional longitudinal reinforcement at the beam tension side. The beam with additional steel bars exhibited ductile behavior with a stable increase in the beam resistance to the applied load; however, the addition of FRP layers enhanced the flexural capacity of the beam and greatly controlled the deformability of the beam after steel yielding, resulting in the lowest measured residual deflection.

This paper proposes an analytical method for predicting the nonlinear behavior of reinforced concrete (RC) beams after flexural strengthening with near surface mounted (NSM) fiber reinforced polymer (FRP) laminates. With a gradual increase in the beam curvature and a step-by-step numerical integration method, an algorithm model was designed for predicting the load-deflection response of RC beams strengthened with the NSM technique. Based on the bond mechanism between the NSM FRP laminates and the surrounding concrete, the available calculation methods of the load bearing capacity of RC beams with NSM FRP laminates were derived according to the bearing capacity model for the strengthened RC structure with FRP materials. Using the proposed model, the load-deflection responses of five flexural strengthened RC beams with NSM carbon FRP (CFRP) laminates were analyzed and verified against the experimental results. The presented results indicate that the proposed model based on the available test data can accurately analyze the tensile stresses of the NSM CFRP laminates. Moreover, the results prove the feasibility of the designed algorithm model in precisely predicting the nonlinear behavior of RC beams strengthened with NSM CFRP laminates. The proposed algorithm model could provide a much needed link between structural design and nonlinear behavior analysis of RC structures strengthened with the NSM technique.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures, in addition to the structural integrity of platforms components under the maximum and minimum operating loads when subjected to the environmental conditions. In-place analysis have been executed to check that the structural member with all appurtenance´s robustness have the capability to support the applied loads in either storm or operating conditions. A nonlinear finite element analysis is adopted for the platform structure above the seabed and pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The SACS software is utilized to calculate the dynamic characteristics of the platform model and the response of platform joints then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have significant effects in the results of the in-place analysis behavior. The most of bending moment responses of the piles are in the first fourth of pile penetration depth from pile head level. The axial deformations of piles in all load combinations cases of all piles are inversely proportional with penetration depth. The largest values of axial soil reaction are shown at the pile tips levels (the maximum penetration level). The most of lateral soil reactions resultant are in the first third of pile penetration depth from pile head level and approximately vanished after that penetration. The influence of the soil-structure interaction on the response of the jacket foundation predicts that the flexible foundation model is necessary to estimate the force responses demands of the offshore platform with a piled jacket-support structure well.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures, in addition to the structural integrity of platforms components under the maximum and minimum operating loads when subjected to the environmental conditions. In-place analysis have been executed to check that the structural member with all appurtenance´s robustness have the capability to support the applied loads in either storm or operating conditions. A nonlinear finite element analysis is adopted for the platform structure above the seabed and pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The SACS software is utilized to calculate the dynamic characteristics of the platform model and the response of platform joints then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have significant effects in the results of the in-place analysis behavior. The most of bending moment responses of the piles are in the first fourth of pile penetration depth from pile head level. The axial deformations of piles in all load combinations cases of all piles are inversely proportional with penetration depth. The largest values of axial soil reaction are shown at the pile tips levels (the maximum penetration level). The most of lateral soil reactions resultant are in the first third of pile penetration depth from pile head level and approximately vanished after that penetration. The influence of the soil-structure interaction on the response of the jacket foundation predicts that the flexible foundation model is necessary to estimate the force responses demands of the offshore platform with a piled jacket-support structure well.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures, in addition to the structural integrity of platforms components under the maximum and minimum operating loads when subjected to the environmental conditions. In-place analysis have been executed to check that the structural member with all appurtenance´s robustness have the capability to support the applied loads in either storm or operating conditions. A nonlinear finite element analysis is adopted for the platform structure above the seabed and pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The SACS software is utilized to calculate the dynamic characteristics of the platform model and the response of platform joints then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have significant effects in the results of the in-place analysis behavior. The most of bending moment responses of the piles are in the first fourth of pile penetration depth from pile head level. The axial deformations of piles in all load combinations cases of all piles are inversely proportional with penetration depth. The largest values of axial soil reaction are shown at the pile tips levels (the maximum penetration level). The most of lateral soil reactions resultant are in the first third of pile penetration depth from pile head level and approximately vanished after that penetration. The influence of the soil-structure interaction on the response of the jacket foundation predicts that the flexible foundation model is necessary to estimate the force responses demands of the offshore platform with a piled jacket-support structure well.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures, in addition to the structural integrity of platforms components under the maximum and minimum operating loads when subjected to the environmental conditions. In-place analysis have been executed to check that the structural member with all appurtenance´s robustness have the capability to support the applied loads in either storm or operating conditions. A nonlinear finite element analysis is adopted for the platform structure above the seabed and pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The SACS software is utilized to calculate the dynamic characteristics of the platform model and the response of platform joints then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have significant effects in the results of the in-place analysis behavior. The most of bending moment responses of the piles are in the first fourth of pile penetration depth from pile head level. The axial deformations of piles in all load combinations cases of all piles are inversely proportional with penetration depth. The largest values of axial soil reaction are shown at the pile tips levels (the maximum penetration level). The most of lateral soil reactions resultant are in the first third of pile penetration depth from pile head level and approximately vanished after that penetration. The influence of the soil-structure interaction on the response of the jacket foundation predicts that the flexible foundation model is necessary to estimate the force responses demands of the offshore platform with a piled jacket-support structure well.

This study aimed to investigate the flexural behavior of T-section semi-precast reinforced concrete (RC) beams composed of recycled aggregate concrete (RAC) and natural aggregate concrete (NAC). The experimental program consisted of four large-scale T beams, including three semi-precast T-beams and a reference RC T-beam made of traditionally cast high strength natural aggregate concrete (HSNAC). The web of all the semi-precast beams composed of a precast U-shaped part, which contained the longitudinal and transverse reinforcement and was cast of HSNAC, and an inner RAC core. Normal strength RAC (NSRAC) or high strength RAC (HSRAC) was used as web core filler, and HSNAC or HSRAC was used for the beam flange. Two techniques were adopted to fill the web core: the traditional concrete casting and the placement of well-sized precast concrete blocks. The results indicated the applicability of RAC and NAC in one section to achieve comparable strength, deformability, and failure mode to those of the monolithically cast beam with NAC. In addition, using precast RAC blocks as filler in the web core of RC beams is a promising construction technique, which can be adopted as a critical design parameter to control development, propagation, and width of flexural and shear cracks to a large extent.

More than 40 models have been established to date to determine the axial compressive behavior of noncircular (square or rectangular) concrete sections confined with fiber-reinforced polymers (FRPs) under concentric loadings. In this study, these models were classified into four groups, represented by nine analytical models. The accuracies of these models to capture the cyclic response of seven noncircular RC columns subjected to axial and reversible horizontal loads were evaluated. Specifically, the predicted responses revealed that the studied models predicted a premature FRP rupture failure mode, and in turn the simulation process was aborted early, revealing a low deformability capacity. By scrutinizing the available results, it was concluded that the axial compression behavior of the FRP-wrapped concrete was dependent on the applied loads, e.g., concentric axial load or axial load and bending moment. Subsequently, one of the examined models was adopted and revised to consider this effect. The modified model can accurately and safely simulate the lateral response of RC noncircular columns retrofitted with FRP, and it can be expanded for general application after verification against a notably large number of noncircular columns.

Clock synchronization has been a challenging task in the design of wireless networks because the synchronization accuracy suffers from uncertain transmission delay and/or packet loss due to poor wireless channel conditions. To address this problem, this paper develops a robust clock synchronization schemes based on matrix completion theory to improve the accuracy in presence of random transmission delay and packet loss. We propose a matrix completion based maximum likelihood estimator (MC-MLE) to estimate the clock offset and clock skew under Gaussian transmission delay model. Thanks to the denoise feature of matrix completion, the proposed schemes outperform the maximum likelihood estimator (MLE) in the presence of packet loss and random transmission delay. That is, the proposed schemes are closer to the Cramer-Rao lower bound (CRLB) than the MLE when the timestamp packets are randomly corrupted. The robustness and accuracy of the proposed schemes are validated by numerical results.

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