Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
Based on the project of Modaoxi Bridge, an experimental study on the compressive behavior of ultrahigh strength concrete filled\nsteel tube (UHSCFST) short column was conducted.Atotal of 9UHSCFST specimens were tested, and the cube strength (...
CFRP has been used mainly for strengthening of existing structures in civil engineering area. Prestressed strengthening is being\nstudied to solve the bond failure model featuring EBR and NSMR methods. The largest disadvantage of the prestressing system\nis that the system cannot be removed until the filler is cured. This problem lowers the turning rate of the equipment and makes\nit limited to experiment, which stresses the necessity of a new prestressing system. Therefore, the present study applies a new\nprestressing systemwhich reliefs the need to wait until the curing of the filler after jacking to the prestressing ofNSMR and examines\nthe effect of the prestressing size and location of the anchorage on the strengthened behaviour.The experimental results show that\nthe crack and yield loads increase with higher level of prestress, while the ductility tends to reduce, and the anchor plate should\nbe installed within the effective depth ...
Based on Hamilton�s principle, this study has developed a continuous treatment for the steel-concrete composite truss beam\n(SCCTB). It has also deduced the SCCTB element stiffness matrix and mass matrix, which include the effects of interface slip,\nshear deformation, moment of inertia, and many other influencing factors. A finite beam element method (FBEM) program for\nSCCTB�s natural vibration frequency has been developed and used to calculate the natural vibration frequencies of several SCCTBs\nwith different spans and different degrees of shear connections. The FBEM�s calculation results of several SCCTBs agree well with\nthe results obtained from ANSYS. Based on the results of this study, the following conclusions can be drawn. For the SCCTB with\nhigh-order natural vibration frequency and with short span, the effect of the shear deformation is greater. Hence, the effect of the\nshear deformation on the SCCTB�s high-order natural vibration frequency cannot be ignored. On the other hand, the effect of the\ninterface slip on the SCCTB�s high-order natural vibration frequency is insignificant. However, the effect of the interface slip on the\nSCCTB�s low-order natural vibration frequency cannot be ignored....
Available guidelines do not provide design procedures for the general case of retrofitting\nreinforced concrete (RC) columns using fiber reinforced polymer (FRP) sheets subjected to\nsimultaneous bi-axial flexural and axial loads. In many practical cases, columns essentially undergo\nsimultaneous axial force and bi-axial bending moments, especially in in-situ construction. This paper\nsuggests a simplified design method based on the equivalent uni-axial moment concept to calculate\nthe required number of layers FRP sheets for retrofitting RC square columns. The proposed procedure\nis then verified against available bi-axial moment and axial force test data found in the literature.\nResults demonstrate that the proposed procedure is appropriate for practical applications with\nacceptable accuracy. It also appears that retrofitting RC square columns by longitudinal fiber\narrangement is only effective for columns with tension-controlled behavior, while transverse and\ncombined longitudinal-transverse arrangements are more effective in enhancing the load bearing\ncapacity of both the compression- and tension-controlled columns. A design example will also\nbe presented....
A three dimensional finite element of nonlinear pushover analysis for short\nspan Reinforced Concrete (RC) bridge with circular piers cross section is\nmodeling to present effects of soil structural interaction (SSI). Structural elements\nmodels are including linear foundation springs modeling, and nonlinear\nRC piers modeling. The paper succeeded to present the SSI effects of\nnonlinear pushover analysis of short spans RC bridges to determine the significant\neffects on dynamic characteristics and displacement capacity of short\nspan RC bridges performance; that is increasing within range 11% to 20%\ncompared to baseline pushover analysis of bridge without SSI effects. Results\nshow the bridge stiffness decreases due to SSI effects on the bridge support for\nmore flexible soils types that generates large displacement, with corresponding\nless base shear in bridge piers and footings by average percentage 12% and\n18%, which is important for structural evaluation for new bridge construction\nand also, for strengthening and repair works evaluation of existing bridges....
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