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Effect of Soil-Structure Interaction
on Building Response in Hilly Areas
-- Prabhat Kumar, Sharad Sharma and A D Pandey
Housing and other infrastructure in hilly regions have evolved with time in such a manner that it closely follows the topographical characteristics and blends itself into the environment without compromising the landscape of the area. The structural forms most commonly encountered are usually the stepback or stepback-setback configurations, since they can easily comply with the spatial restrictions. Structurally, such a configuration is symmetric about an axis but asymmetric about an orthogonal axis. The asymmetry so introduced is responsible for pronounced torsional effects. Considering the fact that hilly regions in the northern part of India are also the most seismic-prone areas, it becomes imperative to critically assess the behavior of such structural forms as prevalent in the region. Static and dynamic analysis was carried out taking into account the soil-structure interaction effects of both structural forms that highlight the differences in design parameters when compared with conventional forms, and also the role of foundation flexibility in the design parameters. © 2012 IUP. All Rights Reserved.
Adaptive Neuro-Fuzzy Inference System-Based
Modeling for HSC Columns Strengthened
with GFRP Wraps Under Compression
-- J Saravanan, K Suguna and P N Raghunath
The paper presents the results of a study on the performance of Glass Fiber-Reinforced Polymer (GFRP) wrapped High Strength Concrete (HSC) columns under uniaxial compression. The columns had slenderness ratios of 8, 16, 24 and 32. Three types of wrap materials (chopped strand mat GFRP, unidirectional cloth GFRP, and woven roving GFRP) were used with 3 mm and 5 mm thickness. The columns were tested under monotonic axial compressive loading up to failure. The deflections and axial strain were noted for each load increment. The HSC columns with GFRP wrapping exhibited improved performance in terms of ductility and energy absorption capacity. Adaptive Neuro-Fuzzy Inference System (ANFIS) modeling was proposed for predicting the performance parameters. A better correlation was observed between the test results and those predicted through the proposed modeling. © 2012 IUP. All Rights Reserved.
Non-Destructive Evaluation of Concrete Structures
with Ground Penetrating Radar
and Influencing Parameters
-- P Srinivasan, K Ravisankar and S Thirugnanasambandam
Infrastructures are constructed with reinforced and prestressed concrete. For quality assurance and quality control, non-destructive techniques are adopted. In India, rebound hammer and ultrasonic pulse velocity test are widely used. Most of the time, it becomes necessary to find the reinforcements and ducts present in the concrete structure. Ground Penetrating Radar (GPR), shortly called radar, is one of the advanced non-destructive techniques, used for inspection of concrete structures, pavements and to detect reinforcements and ducts in concrete. It is also used for quality assessment and to locate flaws inside the concrete. It is based on the propagation of short electromagnetic waves of frequency 1.0 GHz to 2.5 GHz. This paper focuses on the detection of reinforcements and ducts which are present inside the concrete and simulated specimens. The effect of grid spacing during the collection of data is an important parameter in locating the reinforcements and ducts. The effect of grid spacing that is effective in identifying the reinforcements and ducts was studied and reported. © 2012 IUP. All Rights Reserved.
Strength of Brick Masonry Prisms
When Cement Is Replaced with Fly Ash
-- C Nagendra Prasad and B Vidya
The paper presents variation of strengths in brick and brick masonry prism with every percentage increment of fly ash. The brick strength ranged between 3.2 and
3.94 N/mm2. Masonry prism strength using these bricks in cement mortar of 1:3 is partially replaced with fly ash by 10%, 20%, 30%, 40% and 50%, and compared with cement mortar of 1:2 and 1:4. Numerical equation is derived for 1:3 cement mortar using regression analysis. It was observed that the compressive strength of 1:3 cement mortar with 20% fly ash is higher than that of 1:4 cement mortar. © 2012 IUP. All Rights Reserved.
Retrofitting of Soft-Storey Buildings
Using Brick Infills and Steel Bracings
-- Sonu Samanta and Radhikesh P Nanda
Reinforced Concrete (RC) frame buildings with masonry infill panels are becoming increasingly common in urban and semi-urban areas all over India. Many such buildings constructed in recent times have a special feature of the ground storey being left open for the social purpose of parking, i.e., columns in the ground storey do not have any partition walls (of either masonry or RC) between them. These buildings are immanently vulnerable to collapse or damage due to earthquake. In this study, an attempt has been made to conduct a nonlinear static analysis (pushover analysis) of a 6-storey RC soft-storey building followed by retrofitting with different combinations of masonry infill and steel bracings. It is concluded that the performance of the soft-storey building can be increased by providing a few infills at the ground without affecting the parking. © 2012 IUP. All Rights Reserved.
Topology Optimization of Structures
for Minimum Structural Compliance
-- A Mallika and N V Ramana Rao
Recently, topology optimization or layout optimization has become a popular topic in the field of optimal design. Topology optimization has been successfully applied to many different types of structural design problems. Most FEM codes have implemented certain capabilities of topology optimization. In this paper, the problem of optimizing the structural topologies is studied for maximizing the static stiffness. In static topology optimization, minimum compliance is considered as objective function to maximize the static stiffness with a constraint on volume. Numerical examples of simple structures, such as cantilever beam, deep beam and bridge pier problems, are investigated and the results are presented. © 2012 IUP. All Rights Reserved.
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