An improved theoretical formulation is proposed here to predict the moment field induced in laterally loaded RC rectangular stiffened plates including the effect of strength and stiffness of the internal stiffening beams. Design charts are also presented for their quick proportioning. The study reveals the effect of strength and stiffness of the internal beams on the moment field induced in the plate-system which was not considered, currently, by various methods prescribed by different design codes. The use of stiffened-plates becomes mandatory in buildings to accomodate some architectural constraints as well as for satisfying the serviceability criterion of design codes. This type of a structural system is efficient, economical and readily constructible in most of common materials. Moreover, it can be built as a monolithic unit or as a composite system comprising a plate cast in concrete and beams constructed in prestressed concrete, fabricated sections in steel, and so forth. A working example is presented to demonstrate the validity and efficiency of the simplified approach in comparison to finite element based design and other code prescribed methods. and Obsahuje seznam literatury a Appendix A
This paper evaluates the feasibility of using an Artificial Neural Network (ANN) model for estimating the nominal shear capacity of Reinforced Concrete (RC) beams against diagonal shear failure subjected to shear and flexure. A feedforward back-propagation ANN model was developed utilizing 622 experimental data points of RC beams, which include 111 deep beams data and 20 beams tested for low longitudinal steel ratios. The ANN model was trained on 70% of the data and then it was validated using the remaining 30% data (new data were not used for training). The trained ANN model was compared with three existing approaches, including the American Concrete Institute (ACI) code. The ANN model predictions when compared to the experimental data were very favorable, regarding also the other approaches. The prediction of ANN model was also checked for size effect and deep beams separately. The ANN model was found to be very robust in all situations. The safe form of ANN model was also derived and compared with the design equations of the three methods.
Frequency response analysis of hybrid aluminium beam with piezoelectric actuators was performed using finite element method The finite element model was implemented in Matlab software. The one-dimensional beam element is based on Euler-Bernoulli theory and it assumes bilinear distribution of electric field potential. The piezoelectric actuators were driven by harnonic signal around the first eigenfrequency and the beam oscillations were investigated. Results were compared to experiment. and Obsahuje seznam literatury
The paper deals with stress concentration in inclined bars and beams, where the shoulder radius is often not prescribed in the detail drawings. The commonly accepted notch definition as a stepwise change of the beam cross section, as well as a lack of
nomograms or other data on stress concentration in inclined shoulders in the available literature ([1], [2], [3]) support the assumption of negligible stress concentration in inclined shoulders. Several failures of shaft-like components with inclined shoulders made us to investigate the stress concentration in these shoulders. Computational modelling confirmed a rather high stress concentration even in shoulders with a very low inclination β angle. Even in the case of β = 30°, the stress concentration factor is only slightly lower than in a comparable perpendicular (β = 90°) shoulder. Therefore nomograms for evaluation of stress concentration factors in inclined bar and beam shoulders under basic loading types were created and published in the paper.