| Modelling of Monthly Streamflows using Stochastic and ANN Models | Streamflow modelling is essential for planning, designing and operation of water resources projects. In the present study, monthly streamflows during monsoon period at a gauging site were modelled using the streamflows of the previous periods at the gauging site and, the streamflows at the upstream gauging sites using stochastic and artificial neural network models. The gauging sites of Mancherial, Perur and Polavaram of Godavari basin and, Agraharam, Wadanapalli and Vijayawada of Krishna basin were selected for the present study.The study reveals that the performance of stochastic models at the gauging sites is satisfactory and the optimal artificial neural networks showed significant improvement at the upstream gauging sites over stochastic models. The stochastic streamflow models may satisfactorily be adopted at the downstream gauging sites of Godavari and Krishna basins where the flows do not exhibit much of nonlinearity and, ANN models at the upstream gauging sites for the estimation of streamflows. |
| 2 |  | Behaviour of Under-designed Beam-column Joints Upgraded by Steel Bracing in form of Haunch | A large number of gravity load designed (GLD) reinforced concrete (RC) structures are present throughout the world which are extremely vulnerable during earthquake. Various techniques are being proposed by the researchers to upgrade the GLD structures. Introduction of steel bracing at the beam-column joint of RC structures is one of the modern techniques which is gaining considerable interest from research community. A diagonal metallic haunch system is introduced at the beam-column connections to protect the joint panel zone from extensive damage and brittle shear mechanisms.In this paper, a study is presented to evaluate the influence of different parameters, such as, angle of inclination, location of bracing and axial stiffness of the steel bracing on force transfer mechanism. Further, it is shown that the strength hierarchy which is the most important parameter can be rectified and a desirable failure mode by judiciously adopting the geometric configuration of the bracing system can be achieved. |
| 3 | | Retrofitting of Multi-bay Multi-storied RC Frames for Lateral Load Resistance | This paper deals with an experimental investigation carried out to examine the effectiveness of ferrocement wrapping system for retrofitting of reinforced concrete (RC) multi-bay multi-storied frames. Two identical one fourth scaled down three-bay, three storied reinforced concrete frames were cast and subjected to lateral reversed cyclic loading. One specimen was loaded till failure and the other was subjected to 80% of its load carrying capacity.After unloading, distressed beam-column joints of the frames were retrofitted with ferrocement wrapping and subjected to same loading sequence. The performance parameters such as strength, stiffness degradation and ductility factors were obtained and the results are presented. The ferrocement wrapping system is observed to be an effective measure of retrofitting of distressed Reinforced Concrete frames. |
| 4 | | Flexural Analysis of Deep Beams using Trigonometric Shear Deformation Theory | In the present paper, the flexural analysis of deep beams using trigonometric shear deformation theory taking into account transverse shear deformation effects is presented. The number of variables in the present theory is same as that in the first order shear deformation theory. The sinusoidal function is used in displacement field in terms of thickness coordinate to represent the shear deformation effects. The transverse shear stresses can be obtained directly from the use of constitutive relations with accuracy, satisfying the shear stress free conditions on the top and bottom surfaces of the beam. Hence, the theory obviates the need of shear correction factor.Governing differential equations and boundary conditions are obtained by using the principle of virtual work. The deep isotropic beams are considered for the numerical studies to show the efficiency of the theory. It has been shown that the theory is capable of predicting the local effects due to concentrated load. The results obtained for flexure of simply supported, uniform, isotropic beams using the present theory are presented and discussed critically with those of other theories, and are found to agree well with the exact elasticity results wherever applicable. |
| 5 | | Effect of Infill on Performance of Frame Buildings | Masonry infill walls are provided in reinforced concrete frame buildings as cladding and partitions. The infill walls increase the stiffness of buildings and influence the dynamic response. The Indian seismic code takes care of the effect of infill indirectly through approximate period formula. In this paper the consequence of the codal procedure of design on nonlinear performance of reinforced concrete frame buildings with infill have been investigated. Four building plans and two building heights have been considered. In the first phase of the investigation, the performance of the buildings designed as per Indian codes has been evaluated through pushover analysis and nonlinear time history analysis.In the second phase of the investigation, the same designed buildings are fitted with diagonal infill struts modeled as per FEMA-356. The performance of the buildings is again evaluated and the results are compared with the former set of results. The second set of evaluation is realistic and reflects the real seismic condition when the buildings shake along with infill walls. From the results it has been found that evaluation of building performance only by using period formula and base shear correction and without incorporating infill strut elements in the model exhibit inferior performance and, hence, may be misleading. |
| 6 | | Effect of Countdown Timers on Red Light Violations under Heterogeneous Traffic Conditions | The expectation with which timers are installed at signals is that they will reduce lost times, delays and accidents. However, studies which analysed the correctness of these assumptions on the effectiveness of timers by systematic analysis are very limited and none of them were from Indian traffic conditions. Present study is an attempt in this direction to study the effect of timers on red light violations (RLV). This study was carried out using video data collected at a four legged signalized intersection in Chennai, with and without timer. Classified violations were counted at the start and end of red, for every signal cycle.The data is analyzed and the effect of various parameters on RLV was evaluated and a model was developed. The results indicated that, contrary to expectation, the over all number of violations is increasing with the presence of timer. Also, this increase in RLVs was observed to happen at the end of red. Overall, the study sheds light on the nature of red light violations with respect to timer presence, and can be useful for decision makers on the effectiveness of installing timers at intersections. |
| 7 | | Seismic Design of Buildings with Viscous Fluid Dampers – A Methodology | A seismic design methodology for designing of the buildings with linear Viscous Fluid Dampers (VFDs) installed in different brace configurations, using Linear Static Procedure (LSP) and Linear Dynamic procedure (LDP) of IS: 1893-2002 and, energy dissipation device design methodology described in FEMA 273/274 and FEMA 356 is proposed.The developed methodology is used for designing the dampers to the required effective damping in a 3-storey scale down model of a steel building with diagonal, chevron, upper, lower and reverse toggle damper configurations. The developed procedure helps in selecting optimum number, capacity and their distribution of dampers in different floors of the building. |
| 8 | | Influence of Facing Rigidity on the Stability of Reinforced Soil Retaining Walls | Reinforced soil retaining walls are retaining walls consisting of alternating layers of granular backfill and reinforcing strips with a facing. The performance advantages combined with low materials volume and a rapid, predictable and easy construction process make reinforced earth an extremely cost-effective solution over conventional retaining structures. Segmental retaining walls with modular block facings are a better development over the ordinary reinforced earth retaining walls where only a thin facing is provided.The present investigation is aimed at studying the influence of facing rigidity on the structural stability of a reinforced retaining wall. It includes a comparative study of the performance of a reinforced earth segmental retaining wall against an ordinary reinforced earth retaining wall. It is seen from the studies that the facing rigidity is an important factor, which controls the deformation in a reinforced soil wall system. |
| 9 | | Optimal Design of Different Shaped Polymer Modified Ferrocement Roofing/Flooring Elements using Genetic Algorithms | Studies on flexural behaviour of ferrocement roofing/flooring elements indicate that these elements can be made structurally more effective by minimising the deflection and cost. This could be achieved by using an optimum cross-section for the elements. For arriving at the optimum shape of ferrocement flexural elements, optimization techniques capable of handling combinatorial problems are required.Genetic Algorithms based optimal design methodologies provide techniques for realistic modelling of such systems and help in arriving at rational and optimal solutions. This paper presents the formulation of optimal design for channel shaped and trapezoidal shaped ferrocement structural elements in detail with identification of design variables, objective function and constraints. Optimised section details obtained from the study is also discussed in this paper. |
