505 research outputs found
Structural Performance of FRP Bridge Deck
No full textThe purpose of this paper is to present fatigue and strength experimental qualifications performed for an all-composite bridge deck. This bridge deck, made up of fiber-reinforced polymer (FRP) was installed on the campus at University of Missouri at Rolla on July 29th, 2000. The materials used for the fabrication of this 30 foot (9.144 m) long by 9 foot (2.743 m) wide deck were 3 inches (76.2 mm) pultruded square hollow glass and carbon FRP tubes of varying lengths. These tubes were bonded using an epoxy adhesive and mechanically fastened together using screws in seven different layers to form the bridge deck with tubes running both longitudinal and transverse to the traffic direction. The cross-section of the deck was in the form of four identical I-beams running along the length of the bridge. Fatigue and failure tests were conducted on a 30 foot (9.144 m) long by 2 foot (609.6 mm) wide prototype deck sample, equivalent to a quarter portion of the bridge deck. The loads for these tests were computed so as to meet American Association of State Highway and Transportation Officials (AASHTO) H-20 truckload requirements based on strength and maximum deflection. The sample was fatigued to 2 million cycles under service loading and a nominal frequency of 4 Hz. Stiffness changes were monitored by periodically interrupting the run to perform a quasi-static test to service load. Results from these tests indicated no loss in stiffness up to 2 million cycles. Following the fatigue testing, the test sample was tested to failure and no loss in strength was observed. The testing program, specimen detail, experimental setup and instrumentation, testing procedure, and the results of these tests are discussed in detail. A finite-element model of the laboratory test was also developed. The results from the model showed good correlation to deflections and longitudinal strains measured during the tests. The design of the bridge deck has been discussed in detail
Testing and Evaluation of Components for a Composite Bridge Deck
No full textIn this paper the results of an experimental investigation conducted on 76 mm (3 in) square hollow pultruded glass fiber-reinforced polymer (GFRP) tubes and their assemblies have been discussed. These GFRP tubes are used in the fabrication of an all-composite bridge deck that is designed for H-20 truckloads as specified by the American Association of State Highway and Transportation Officials (AASHTO). The study is principally focused on the experimental characterization of flexure performance under static loading of pultruded GFRP tubes made of unidirectional glass fibers. Several tests were conducted on single GFRP tubes followed by combinations of two tubes and a four-layered tube assembly. The tubes were bonded together using epoxy adhesive to build the assembly. The specimen details, experimental setup and instrumentation, testing procedure, failure modes and the test results of these experiments have been discussed in detail. A preliminary design model of each test coupon was developed and analyzed using Finite Element Analysis (FEA). Experiments were conducted to corroborate the analytical design model. Comparison between the theoretical and experimental results showed good correlation. Experimental results show excellent linear elastic flexural and shear behavior up to failure. The stiffness of the tubes and their assemblies demonstrate that they can be used in the building of all-composite bridge decks and for other infrastructure applications. Failure modes for the samples under static flexural loads are described
Design and Technologies for a Smart Composite Bridge
No full textAn all-composite, smart bridge design for shortspan applications is described. The bridge dimensions are 9.14-m (30-ft.) long and 2.74-m (9-ft.) wide. A modular construction based on assemblies of pultruded fiber-reinforced-polymer (FRP) composite tubes is used to meet American Association of State Highway and Transportation Officials (AASHTO) H20 highway load ratings. The hollow tubes are 76 mm (3 in.) square and are made of carbon/vinyl-ester and glass/vinyl-ester. An extensive experimental study was carried out to obtain and compare properties (stiffness, strength, and failure modes) for a quarter portion of the full-sized bridge. The bridge response was measured for design loading, two-million-cycle fatigue loading, and ultimate load capacity. In addition to meeting H20 load criteria, the test article showed almost no reduction in stiffness or strength under fatigue loading and excellent linear elastic behavior up to failure. Fiber optic strain sensors were evaluated on the test article during testing. Sensor characteristics are determined as preparation for permanent field installation
Analysis of Long Cantilever Cylindrical Shell Subjected to Wind Loading
No full textBending analysis of closed cylindrical shells subjected to asymmetric load and having different support conditions is of interest in the design of chimneys, water towers, oil storage tanks, etc. A simple method of analyzing a long cantilever cylindrical shell, subjected to asymmetric load, is presented in the paper, using Schorer’s shell theory and orthogonal functions. The application of the solution has been illustrated with an example of a cantilever shell subjected to wind loads. The results obtained for this problem have been compared with the previously available results to illustrate the accuracy of the results obtained here. The solution presented can also be extended to a cylindrical shell with other support conditions, as well as to the study of free vibration of a cylindrical shell. The present solution will be very useful for designers who need to obtain numerical results for specific problems with minimum computational effort
Free Vibrations of Anisotropic Laminated Doubly Curved Shells
No full textFree vibration characteristics of laminated composite shells are presented using an isoparametric doubly curved quadrilateral shear flexible element. First-order shear deformation theory is accounted for using an extension of Sanders\u27 shell theory. The effects of in-plane inertia and rotary inertia are considered in the formulation of the mass matrix. Numerical results are presented for the doubly curved composite shells to study the influence of various important aspects of the problem such as change in shell geometry, orientation of layers, material parameters, and boundary conditions on the frequencies. Results for plates and cylindrical shells are also presented as special cases and are compared with those available in the literature
Buckling of Multilayered Composite Plates under Uniform Temperature Field
No full textThe buckling behavior of generally layered composite plates subjected to a uniform temperature field is studied. Transverse shear flexibility is accounted for in the analysis using the thermoelastic version of the first order shear deformation theory. Numerical results are presented for thermal buckling problems using a nine noded isoparametric quadrilateral finite element. The influence of boundary conditions, ply orientation, and plate geometries on the critical buckling temperature is examined
Buckling of Laminated Cylindrical Panels under Uniaxial Compression
No full textBuckling characteristics of anisotropic laminated cylindrical panels are presented using an isoparametric nine-noded rectangular element. Kinematic relations, extended to include the first-order shear deformation theory, are utilized in the formulation. Numerical results are presented for laminated cylindrical panels under uniaxial compression loading to illustrate the influence of panel sizes, orientation of layers, material properties, and boundary conditions on the buckling loads. Results for plates are also presented as special cases and are compared with the available solutions
Thermal Buckling of Laminated Plates Using a Shear Flexible Finite Element
No full textThe buckling behavior of laminated composite plates subjected to a uniform temperature field is studied. Transverse shear flexibility is accounted for in the analysis using the thermo-elastic version of the first-order shear deformation theory. The prebuckling behavior of the plate under a uniform temperature field is studied prior to predicting the initial thermal buckling load. Numerical results are presented for thermal buckling problems using a nine-noded isoparametric quadrilateral finite element. The influence of boundary conditions, ply orientation, and plate geometries on the critical buckling temperature is examined
- …
