Loading...
| Friend's email | |
| Your name | |
| Your email | |
| enter code | |
This page was sent successfuly
- Type of Document: Ph.D. Dissertation
- Language: Farsi
- Document No: 40767 (09)
- University: Sharif University of Technology
- Department: Civil Engineering
- Advisor(s): Kazemi, Mohammad Taghi
- Abstract:
- This study deals with the monotonic behavior of reinforced concrete membranes. In the first step, small reinforced concrete membrane panels were studied. Examining the available test results on reinforced concrete panels, a new set of stress-strain relations for normal strength concrete and mild steel bars embedded in concrete. The salient features of the proposed constitutive laws are: 1) considering the effect of reinforcement ratio on average stress-strain relationships of cracked concrete; and 2) considering the gradual reduction of average stiffness of steel bars embedded in concrete. Equilibrium, compatibility, and constitutive relationships were incorporated into an algorithm to obtain a procedure for analyzing reinforced concrete membrane elements. Corroboration with data from panel test specimens shows that the presented model provides good predictions for the entire load-deformation response of membrane elements over a wide range of conditions. Furthermore, in situations that other prevailing smeared crack models have shown to suffer from reduced accuracy, the presented model provides good accuracy. In the next step, a finite element implementation of the proposed constitutive relations using a secant formulation is presented. The procedure is capable of predicting the full load-deformation response of reinforced concrete membrane structures. The model was verified and validated using the results of a classic set of experiments on shear- critical beams with and without stirrups. In spite of utilizing simple 4-node elements the presented finite element code was found to have a good accuracy in estimating stiffness, deformation, and load capacity of the test beams.
In another part of this research, a new simple expression for shear capacity of reinforced concrete beams without stirrups was derived. The proposed relation captures the dependence of shear strength on size, shear span-to-depth ratio, longitudinal reinforcement ratio, maximum aggregate size, and concrete strength. The limits of this formula agree well with the limit solutions of shear failure load for very small and very large sizes; based on plastic and fracture mechanics solutions, respectively. The proposed relation were calibrated by least-square fitting of the existing experimental database (consisting 398 data) and resulted in low coefficients of variation.
- Keywords:
- Reinforced Concrete ; Beams ; Resistance ; Smeared Crack Model ; Membrane Element ; Nonlinear Finite Element Analysis ; Load-Deformation Response
Digital Object List
-
محتواي پايان نامه
- view
Bookmark