Retrofitting Notch Damaged Box Steel Beams with Composite Materials (original) (raw)
Related papers
Experimental and Numerical Studies of Structural Performance of Notch Damaged Steel Beams
Proceedings of International Structural Engineering and Construction, 2019
Performance of notch damaged unrepaired steel I-shaped beam specimens was examined experimentally and numerically simulated using finite element modeling. Nine U-shaped notch damaged specimens and one control beam specimen were considered. The nine unrepaired laterally unsupported I-shaped full-scale steel specimens were tested in two-point loadings and the parameters considered in the study were the size and location of the notch. The notch size was 30 mm, 40 mm, and 60 mm in depth with a constant opening width of 20 mm. The location of the notch was at one-quarter, one third, and middle of the specimen clear span. All pre-damaged specimens had notches on one side of the tension flange with respect to the beam web except for two specimens where two notches were cut at the middle of the specimen clear span on both sides of the tension flange. The test specimens were modeled analytically using three-dimensional models of the bare-steel I-shaped specimens for comparison of the analyti...
Enhancing Ultimate Compressive Strength of Notch Embedded Steel Cylinders Using Overwrap CFRP Patch
Applied Composite Materials, 2011
In this study, the application of Fiber Reinforced Polymer (FRP) patch for strengthening of the damaged area in thin walled steel cylinders under compression loading was investigated. In this direction, some experimental tests were carried out on the selected notch induced specimens with unique diameter-to-thickness ratio (D/t). The obtained results were compared to the intact cylinder in order to find out the reduction effect of notch on the buckling load of cylinders. Following that, the notched specimens were treated using externally FRP by wrapping around the notched area and the stability strength of the retrofitted specimens was measured experimentally. The investigation was also carried out in numerical analysis using FEM in order to develop the proposed technique for determination of optimum FRP configurations and also better understanding of the experimental observations considering the nonlinear behavior and failure modes for composite member.
Shear Repair of P/C Box Beams Using Carbon Fiber Reinforced Polymer (CFRP) Fabric
2006
The report documents the retrofit work carried out on the KY3297 Bridge over Little Sandy River in Carter County, Kentucky. Field investigation and evaluation revealed that the bridge superstructure was deficient in shear. The repair work was carried out using externally bonded carbon fiber reinforced polymer (CFRP) fabric system. The repair, using externally bonded fiber system, offers the following benefits: (1) the use of light construction equipment, hand kits and tools, (2) minimal traffic disruption as all lanes were open to traffic while work was being performed underneath the bridge, and (3) cost saving; the cost for the repair and 3-years monitoring was USD 105,000.00comparedtotheestimatedsuperstructurereplacementcostofUSD105,000.00 compared to the estimated superstructure replacement cost of USD 105,000.00comparedtotheestimatedsuperstructurereplacementcostofUSD600,000.00. The repair began in June 2001 and was completed in October 2001. After the repair, crack gauges were used to monitor all shear cracks that existed in the bridge. Inspection of the bridge was carried out at specific intervals from October 2001 to July 2005. No crack movement has been observed during the inspections. This indicates that the retrofit was a success.
Analytical and experimental study on repair effectiveness of CFRP sheets for RC beams
Journal of Civil Engineering and Management, 2013
This paper presents the results of both analytical and experimental study on the repair effectiveness of Carbon Fibre Reinforced Polymer (CFRP) sheets for RC beams with different levels of pre-repair damage severity. It highlights the effect of fixing CFRP sheets to damaged beams on the load capacity, mid-span deflection, the steel strain and the CFRP strain and failure modes. The analytical study was based on a Finite Element (FE) model of the beam using brick and embedded bar elements for the concrete and steel reinforcement, respectively. The CFRP sheets and adhesive interface were modelled using shell elements with orthotropic material properties and incorporating the ultimate adhesive strain obtained experimentally to define the limit for debonding. In order to validate the analytical model, the FE results were compared with the results obtained from laboratory tests conducted on a control beam and three other beams subjected to different damage loads prior to repair with CFRP sheets. The results obtained showed good agreement, and this study verified the adopted approach of modelling the adhesive interface between the RC beam and the CFRP sheets using the ultimate adhesive strains obtained experimentally. © 2013 Vilnius Gediminas Technical University (VGTU) Press. http://www.tandfonline.com/doi/abs/10.3846/13923730.2013.799095#.Usu2xPuA\_5M
Experimental and numerical analysis of notched CFRP composites under multiaxial loadings
HAL (Le Centre pour la Communication Scientifique Directe), 2017
Experimental quasi-static tests were performed on center notched carbon fiber reinforced polymer (CFRP) composites having different stacking sequences made of G40-600/5245C prepreg. The three-dimensional Digital Image Correlation (DIC) technique was used during quasi-static tests conducted on quasi-isotropic notched samples to obtain the distribution of strains as a function of applied stress. A finite element model was built within Abaqus to predict the notched strength and the strain profiles for comparison with measured results. A user-material subroutine using the multi-continuum theory (MCT) as a failure initiation criterion and an energy-based damage evolution law as implemented by Autodesk Simulation Composite Analysis (ASCA) was used to conduct a quantitative comparison of strain components predicted by the analysis and obtained in the experiments. Good agreement between experimental data and numerical analyses results are observed. Modal analysis was carried out to investigate the effect of static damage on the dominant frequencies of the notched structure using the resulted degraded material elements. The first in-plane mode was found to be a good candidate for tracking the level of damage.
This paper presents the numerical study to simulate the fatigue crack growth of artificially damaged steel Broad Flange I-beams section by single edge notched repaired with carbon fiber reinforced polymer CFRP strips. The study is carried out using ANSYS classic modeling approach is suggested to simulate the fatigue response of the beams, based on the cumulative damage theory and strain life method. Experimental test results were compared with FE results obtained. A parametric study was conducted using the validated model. The considered parameters were the number of CFRP strip layers used in the repair, the applied load range, initial crack length at time of strengthening and the thickness of CFRP strip. The numerical results indicated that the CFRP increased the critical crack length at which fracture occurred, and the strengthening was more effective at lower stress ranges. Moreover, the CFRP Strips can substantially delay failure and the results demonstrate the possibility of technique and highlight the importance of early intervention when repairing fatigue critical details. The ultimate load and ductility decreased substantially with increasing initial crack length at the time of installing the strengthening layer. Furthermore, increased capacity was achieved by increase the CFRP thickness and layers.
Thin-Walled Structures, 2017
This paper investigates the flexural performance of pre-damaged steel-concrete composite beams repaired using externally-bonded carbon fiber-reinforced polymer (CFRP) laminates with and without mechanical anchors. A total of 10 beams were prepared, one beam was left undamaged, whereas nine beams were artificially damaged by cutting different U-shaped notches in the bottom flange at the beams' mid-span that resulted in 45%, 73% and 100% losses in the flange thickness. Three damaged beams were not strengthened, whereas six damaged beams were repaired in flexure using externally-bonded CFRP laminates with and without mechanical anchors. The load-carrying capacities of the unstrengthened beams with damage states of 45%, 73% and 100% were approximately 11%, 23%, and 50% lower than that of the control-undamaged beam, respectively. The CFRP repair schemes were capable of restoring the original load capacity of the damaged beams with the lower damage state of 45%. For the beams with the higher damage states of 73% and 100%, the repair schemes could restore a maximum of 81% of the original load capacity. The inclusion of mechanical anchors in the repair regime improved the strength gain from 15% to 19% and from 46% to 63% for the beams with 45% and 100% damage states, respectively, relative to the strength of the corresponding damaged-unstrengthened beam.
Improving the Performance of Steel Beams by using Carbon Fiber Reinforced Polymer: A Review
2020
In latest years, the application of carbon fiber reinforced polymer (CFRP) composites for strengthening structural elements has become one of the efficient options to meet repair due to fatigue cracking, corrosion or the increasing cyclic loads. Therefore, the aim of this survey is to explore the existing carbon fiber reinforcing polymer (CFRP) techniques used for strengthening structural steel elements that are damaged due to fatigue. The current survey also deals with the researches that studied the efficiency of using (CFRP) in strengthening steel beams and rehabilitating (reestablishing) damaged ones. It also reviews the researches that used the finite element method (FEM) to evaluate the performance of steel beams strengthened by CFRP. Keyword: Steel beams, Carbon fiber reinforced polymer, strengthening steel beams, rehabilitation damaged steel beams, fatigue, Finite element method. ةعجارم لاقم :نوبركلا فايلأب ةمعّدملا تارميلوبلا مادختساب ةيذلاوفلا تابتعلا ءادأ نيسحت اضرلا بايذ...
Composites Part B: Engineering, 2016
As compared to other structural applications of polymeric composites, limited information is available on structural behavior of wood members strengthened with polymer composites. The focus of this paper is to evaluate the structural performance and practical use of wooden beams repaired and retrofitted with fiber-reinforced-polymeric (FRP) composites. The paper presents a summary results of an experimental study on the behavior of both Douglas Fir and Glulam wood beams repaired and retrofitted with different composite strengthening systems. In addition, the paper presents a simplified design procedure to predict the capacity of timber beams strengthened with FRP composites. Two types of composites; wet layup laminates and sandwich panels, and two lamination schedules; unidirectional and bidirectional, and two lamination geometries; U-laminate and flat laminates were evaluated. For "flexure/shear" wood beams repaired and retrofitted with bidirectional, carbon/epoxy U-shaped wet layup laminates, a total of eight Douglas Fir (Dug Fir) Larch # 1 wood beams were tested to failure. For "flexure-only" wood beams retrofitted with flat unidirectional laminates, both wet layup and precured sandwich honeycomb composites were evaluated. Experimental results indicated that the use of composites as external repair and rehabilitation elements resulted in an appreciable increase of both strength and stiffness. A practical case study is also presented that provides a step-by-step procedure for analyzing and designing a polymeric composite system for repair of partially damaged wood girders by fire.