i-manager's Journal on Structural Engineering (JSTE)


Volume 7 Issue 1 March - May 2018

Research Paper

Analysis of Structures Subject to Uncertain Displacements Using Interval Methods

Mehdi Modares*
Associate Professor, Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago, USA.
Modares, M.(2018). Analysis of Structures Subject to Uncertain Displacements Using Interval Methods. i-manager’s Journal on Structural Engineering, 7(1), 1-5. https://doi.org/10.26634/jste.7.1.14277

Abstract

This paper presents a new framework for analysis of structures subjected to imprecise or uncertain displacements through application of interval methods. This pertains to quantification of uncertainty existing in the induced displacements using unknown-but-bounded or interval variables. In deterministic conventional displacement-based structural methods, the unknown displacements are obtained followed by determination of internal forces. In order to attain sharp results, using this method, the two main steps of conventional static analysis is combined which leads to determination of bounds of internal forces/moments as well as internal stresses directly. Using this method, the functional dependencies of uncertain interval parameters are considered in the calculations leading to obtaining sharp results. An example illustrating the behavior of the method developed is presented and the results are compared with Monte-Carlo simulations results.

Research Paper

Lateral - Torsional Buckling of Various Steel Trusses

K.S.Vivek* , C. Ravi Kumar Reddy**, K. S. Sai Ram***
* Assistant Professor, Department of Civil Engineering, VVIT, Andhra Pradesh, India.
** Professor, Department of Civil Engineering, KHIT, Andhra Pradesh, India.
*** Professor, Department of Civil Engineering, RVR & JC CE, Andhra Pradesh, India.
Vivek, K.S., Reddy, C.R.K., and Ram , K.S.S. (2018). Lateral - Torsional Buckling of Various Steel Trusses. i-manager’s Journal on Structural Engineering, 7(1), 6-12. https://doi.org/10.26634/jste.7.1.14280

Abstract

Lateral-torsional buckling behavior of various types of steel trusses without and with intermediate lateral rigid supports is investigated by performing finite element analysis. Commonly used parallel chord trusses, such as Pratt, Howe, Warren (with verticals), K and Diamond trusses of span 8 m and rise 0.8 m are considered. Two different types of intermediate lateral rigid support systems are considered. Elastic critical buckling joint loads of the trusses are found by modeling and performing finite element analysis using ANSYS - commercial software. From the obtained results it can be understood that critical buckling load, the magnitude and shape out of plane deflection depends upon whether the intermediate lateral support is provided or not and if provided, the type of lateral supports and spacing between them. The pattern and inclination of the web lacing also affect the stability of the truss. It is found that the Diamond and K trusses resulted in better stability and hence suggested for use in place of large spans and heavy loading.

Research Paper

A Step by Step Procedure to Perform Isogeometric Analysis of Beam and Bar Problems in Civil Engineering Including Sizing Optimisation of a Beam

K. N. V. Chandrasekhar* , N. S. S. Sahithi**
* Assistant Professor, Department of Civil Engineering, CVR College of Engineering, Hyderabad, India.
** PG Scholar, Department of Civil Engineering, CVR College of Engineering, Hyderabad, India.
Chandrasekhar, K.N.V., and Sahithi, N.S.S. (2018). A Step By Step Procedure to Perform Isogeometric Analysis of Beam and Bar Problems In Civil Engineering Including Sizing Optimisation of a Beam. i-manager’s Journal on Structural Engineering, 7(1), 13-27. https://doi.org/10.26634/jste.7.1.14283

Abstract

The integration of CAD geometry and analysis is really a big advantage of using Isogeometric analysis. The Galerkin weak formulation is used to solve the governing differential equations using the B-splines and NURBS functions. The main focus of this paper is to present a detailed step by step procedure to solve beam and bar problems in Civil Engineering. The beam is analysed for static and dynamic loading, and the bar problem is analysed to find the natural frequency of vibration. The sizing optimization of the beam is also perfomed to determine the optimal cross section dimensions of the beam. The results from the Isogeometric analysis are then compared with the theoretical results. The results from Isogeometric analysis shows a good agreement with those obtained by using the analytical methods. The solution from the Isogeometric analysis has better precision over other standard methods. The structures are designed with a basic set of criteria, which include minimum weight, frequency, compliance, and volume. In this paper, the problems related to the weight and frequency are presented, and this paper provides a few basic examples to discuss in a classroom.

Research Paper

Effect of Suspension to Main Span Ratio on the Behaviour of Cable-Stayed Suspension Hybrid Bridge

G.M. Savaliya* , A. K. Desai**
* Assistant Professor, Department of Civil Engineering, Government Engineering College, Palanpur, Gujarat, India.
** Professor, Department of Applied Mechanics, Sardar Vallabhbhai Patel National Institute of Technology (SVNIT), Surat, Gujarat, India.
Savaliya, G.M., and Desai, A.K.(2018). Effect of Suspension to Main Span Ratio on the Behaviour of Cable-Stayed Suspension Hybrid Bridge. i-manager’s Journal on Structural Engineering, 7(1), 28-34. https://doi.org/10.26634/jste.7.1.14279

Abstract

To accomplish utmost central span in bridges is a fascinating rational challenge. The idea of modified cable-supported bridges has been projected in the past that promise to go beyond the traditional cable-supported bridges in terms of central span length. There are different ways through which long span bridges could be achieved like structural system with innovative form, use of high strength materials, and latest method of analysis and design. The cable supported bridge systems, such as cable-stayed bridge and suspension bridge are used to achieve longer span bridges. The suspension bridge has the ability to offer longer span and cable-stayed bridge has better structural stiffness. Advantages of above system could combine in a system known as long span cable-stayed suspension hybrid bridge. To discriminate behaviour and check the feasibility of this modern form of bridge, 1400 m central span and 700 m side span cablestayed suspension hybrid bridge is selected for analysis. The span of bridge supported by suspenders also influence the behaviour of suspension bridge. Here, the influence of suspension portion is presented in the form of suspension portion to main span ratio. The analysis like modal analysis and nonlinear static analysis is carried out using SAP2000 v14.0.0. The effects of suspension portion to main span ratio on nonlinear static performance of bridge are presented in form of axial forces and bending moment in deck of cable-stayed suspension hybrid bridge.

Research Paper

Influence of VSI Aggregates on Properties of Pervious Concrete

Tejas Joshi* , Urmil Dave**
* Research Scholar, Department of Civil Engineering, Institute of Technology, Nirma University, Ahmedabad, Gujarat, India.
** Professor, Department of Civil Engineering, Institute of Technology, Nirma University, Ahmedabad, Gujarat, India.
Joshi, T. and Dave, U.(2018). Influence of VSI Aggregates on Properties of Pervious Concrete. i-manager’s Journal on Structural Engineering, 7(1), 35-40. https://doi.org/10.26634/jste.7.1.14281

Abstract

This paper investigates the effect of replacement in Vertical Shaft Impactor (VSI) aggregates with Natural coarse aggregates on pervious concrete properties. Pervious concrete is a special type concrete prepared without use of fine sand. Pervious concrete is produced with different size of coarse aggregates. For the present investigation comparison has been made between VSI aggregates and Natural aggregates used in pervious concrete. The physical properties of Natural aggregate and VSI aggregate are compared. For the pervious concrete mix design, cement content, 375 3 -10 kg/m is used with 4.75 mm size of coarse aggregate. Three w/c ratios are used, such as 0.4, 0.425, and 0.45. The main properties were studied, such as void ratio, compressive strength permeability, and density. Comparison of results in Natural aggregate and VSI aggregate for making pervious concrete are included in this paper. Test results reveal considerable enhancement in the compressive strength of pervious concrete and other properties are found in similar range. VSI aggregate is a special type of aggregate having rounded edges. It has been found that VSI aggregates is more suitable to use in pervious concrete as compared to Natural coarse aggregates.

Research Paper

Structural System Prediction Model Based On Cost – Time – Quality Analysis

shashank* , Pratul N. Nema**, P. Sathishkumar***, B. S. Shashank****, B. L. Shivakumar*****
*-*** Department of Civil Engineering, Visvesvaraya Technological University, Belgaum, Karnataka, India.
**** Assistant Professor, Department of Civil Engineering, R.V. College of Engineering, Bengaluru, India.
***** Professor and Former Dean, R.V. College of Engineering, Bengaluru, India.
Shreenidhi, R., Nema, P.N., Sathishkumar, P., Shashank. B.S., and Shivakumar, B.L. (2018). Structural System Prediction Model Based on Cost - Time - Quality Analysis. i-manager’s Journal on Structural Engineering, 7(1), 41-47. https://doi.org/10.26634/jste.7.1.14282

Abstract

In present scenario, most building systems are decided on the basis of experience and preferences of Architects and Structural consultants, but seldom are the Project Management aspects considered. Even when they are considered, it is not done in a systematic manner. Because of this it quite often happens that in the middle of the project there are drastic changes in the building systems adopted, which have implications with time, cost, quality, or all of them. There is a general lack of awareness in industries about the different structural systems available and the knowledge about their reliability in the industry. In this work, the construction management methodologies of various building systems, such as Column beam slab, Post Tensioned slab, Reinforced Concrete Wall, and Flat slab were studied. The authors compared the different systems with respect to parameters like suitability, cost, duration, and quality. The authors have generated a prediction model to identify the suitable building system considering the constraints given by the client. From the overall study, Resource-Cost- Duration analysis of a project is carried out and other parameters are optimized when one parameter becomes a constraint, for efficient construction management.

Case Study

Analysis of Stability of Finite Slopes by Using Visual Slope

K. Ramya Chitra* , D. Kiranmaye**
* M.Tech Scholar, Department of Structural Engineering, Ashoka Institute of Engineering and Technology, Telangana, India.
** Assistant Professor, Department of Civil Engineering, Mahatma Gandhi Institute of Technology, Telangana, India.
Chitra, K.S., and Kiranmaye, D. (2018). Analysis of Stability of Finite Slopes by Using Visual Slope. i-manager’s Journal on Structural Engineering, 7(1), 48-57. https://doi.org/10.26634/jste.7.1.14278

Abstract

Slopes are either man-made (cuttings, embankments for highways, railroads, etc.) or natural (hillside, valleys). Slopes are of two types, viz., finite and infinite. Forces due to instability are force of gravity, force of seepage, earthquake forces, etc. (Ranjan and Rao, 2007). Slope failures are of two types, viz., translational and rotational. Slopes can be analysed by many methods, such as Total stress analysis, Swedish circle method or Method of slices, Bishop's method, Friction circle method, Stability number method, etc. Other than these, different types of software are available for analysis in stability of slopes, for eg: Geoslope, Visual Slope, Geo- Techpidia, C programming, etc. The present work is to analyse the stability of slopes using Visual Slope. Visual Slope is a user-friendly software used for analysis in stability of slopes. By calculating the different input parameters for different trials, least Factor of Safety (F.O.S) could be obtained so that slope can be analysed and stabilised. By using this software, large amount of arithmetic operations can be done within in a few seconds and hence very useful to engineers in the analysis of slope stability.