ISSN 0970-0137
Current Issue
October – November 2016 Vol. 43 no. 4

         
43-28

Directions in self consolidating concrete research : a bibliometric study

M. Mymoon, S. Mahendran, R. Lakshmi Poorna and S. Suryakala

329

Abstract

In this paper the bibliometric analysis of the growth and development of research in the field of Self Consolidating Concrete or Self Compacting Concrete (SCC), based on the scientific literature available from Web of Science during the period from 1997 to 2013. Self-consolidating concrete (SCC) or self-compacting concrete, as it’s sometimes known, arrived as a revolution in the field of concrete technology. During the study period a total of 1579 papers were published in this research area. Data has been extracted using specialized bibliometric software such as HistciteTM and Bibexcel. An in-depth analysis has been done to understand the growth metrics of this research area.

43-29

Expended energy based damage assessment of RC structures: new damage assessment methods

AnthugariVimala, and Ramancharla Pradeep Kumar

341

Abstract

Many past response analyses of the structures under earthquake excitations revealed that both the maximum displacements and the number of large-amplitude displacement responses cause higher damage to the structures. In the present study, a new methodology is proposed for seismic damage assessment of a reinforced concrete framed structure based on the energy dissipated by the structure along the completed displacement path. Three methods are proposed to assess the global damage state of the structure. In the proposed methods, the damage index is expressed at any instant of deformation as the ratio of the expended energy at the instant to the total energy dissipation capacity of the structure.

43-30

Evaluation of seismic vulnerability of multi-storeyed buildings having columns of different heights in a storey using pushover analysis

Amlan K. Sengupta andShubhayan Sarkar

351

Abstract

The variation of the height of the columns in a storey of a multi-storeyed building increases their vulnerability to seismic forces. Assessment of seismic vulnerability of buildings can be carried out by various approaches. In this paper, an approach based on pushover analysis was used for generating vulnerability indices. The indices quantify the deficiencies in lateral load resistance and lateral drift of a building, storey drift, and the performance ranges of the hinges formed in the beams and columns. First, a regular mid-rise reinforced concrete building was analysed to evaluate the vulnerability indices. Next, the study investigated the effects of increased height of the open ground storey, foundations on sloping levels, split-level floors, and partial height infill walls in similar buildings. It was observed that the increase in vulnerability due to the variation of the height of the columns in a storey could be quantified by the indices for lateral load resistance, storey drift, and the performance of the columns in a storey.

43-31

Synthesis methods for β-belite using lime sludge and silica particles

S. Maheswaran, S. Kalaiselvam, G.S. Palaniand Nagesh R. Iyer

362

Abstract

The objective of this study is to compare the methods of synthesis β-phase belite by using lime sludge (LS), a residual solid generated from paper and pulp industry with nano silica (NS) and silica fume (SF). The precursor study shows that LS and calcined lime sludge (CLS) are not generally pozzolanic, but mainly CaCO3/CaO. Three synthesis methods viz., hydrothermal-calcination route, solid state reaction, and mechanochemical are used for the synthesis of belite. Ca/Si molar ratio of 2.0 is used for all the methods. About 94% of pure belite is obtained by solid state reaction method, followed by mechanochemical and hydrothermal methods. The results show that latter two methods consumes more energy by means of calcination of LS, whereas the former consumes less energy. In addition, hydrothermal method with CLS and SF requires water for the chemical reactions and higher sintering temperature of about 1000°C. However, in all the methods, the belite is synthesized without use of any chemical stabilizers. The micro-analytical characteristic features of the raw material, intermediate products and the formed belite are analyzed qualitatively and quantitatively by means of XRD, XRF, TG-MS-DTA, SEM, FT-IR and BET techniques appropriately. Hence, this study leads to novel development of comparatively low-energy cementitious composite materials for future potential applications in the construction field.

43-32

The Evaluation of unexpected results of a seismic hazard applied to a modern Hydroelectric center in central Ecuador

TheofilosToulkeridis

373

Abstract

At the base of Tungurahua volcano, the huge water flow volume and the high waterfalls of the Pastaza River generate the electrical energy in the San Francisco hydroelectric project (SFHP). At this level, the water flows through an 11.2 km tunnel, until the engine room, with an installed capacity of 230 MW. This area is known as a high seismic hazard, the beams and the columns that compose the building should have a specific design that take in account a particular considerations. Unfortunately, the engine room control building of the SFHP, possess beams stronger than the joints and columns. This study presents (a) design performance of the beam-column connection; (b) momentum-curvature relation of the elements obtained; (c) seismic resistance capacity of a structure obtained using the pushover technique; (d) structure performance of a pseudo-spatial seismic analysis; (e) obtaining reduction factor of the seismic forces. Based on this study, it is evidenced that the engine room control building of the SFHP, despite it modern age, is not appropriate to resist for a future seismic event.

43-33

Influence of chemical curing technique on the properties of fly ash aggregates prepared without conventional binders

G.Venkata Suresh and J. Karthikeyan

381

Abstract

In any conventional concrete, the major volume is occupied by the coarse aggregates only. To fill this volume natural crushed aggregates are generally used and bulk usages of these aggregates lead to depletion of natural resources. In India, according to statistics from 2014-15 nearly 42.37% (73.24 million tons) fly ash generated from thermal power stations are unutilized. Usage of fly ash aggregates into concrete has potential for large scale utilization in the construction industry leading to the reduction of environmental degradation, i.e., effective utilization of fly ash. The conventional existing methods of curing like cold bonding, sintering and autoclaving are experiencing some drawbacks. To overcome these drawbacks, a novel chemical curing technique has been proposed in this paper, the aggregates are cured chemically by immersion in a sodium hydroxide (NaOH) solution prepared with different molar ratios i.e 5M, 8M, 10M, 12M. The present study deals with the influence of chemically cured fly ash aggregates on its physical and mechanical properties and is compared with naturally cured and water cured fly ash aggregates. The strength of Chemical Cured Aggregates (CCA) was found to be 64.93% and 49.03% higher after 7 days and 28 days respectively, when compared to that of Water Cured Aggregates (WCA). The percentage of water absorption of CCA is 4.0% at 7 days and 4.2 % at 28 days.

43-34

A study on cold-formed steel web stiffened lipped battened channel columns

G. Beulah GnanaAnanthi, G.S. Palani and Nagesh R. Iyer

390

Abstract

The objective of this paper is to investigate pin ended cold-formed steel built-up battened columns composing of two lipped channels with stiffened webs. Three types of cross section have been chosen for this study, based on the specifications of the American Iron and Steel Institute 2007. A numerical finite element procedure is set up using the ABAQUSsoftware to validate initially by comparing with the experimental data on the behavior of web stiffened cold-formed lipped battened channel columns connected back-to-back. Local and the overall geometric imperfections are included in non-linear material model. The finite element analysis is conducted on columns of different slenderness ratios ranging from 20 to 120. The parametric study includes 66 columns with different depth and battens. Effects of web depth and number of battens on the ultimate load carrying capacity of the built-up battened column have been examined. The numerical results showed a very good agreement with the experimental data’s.The results are compared with Direct Strength Method. Based on the comparison, modification of the design equations in DSM has been proposed for the built-up battened columns.

43-35

Performance of pedestrian bamboo bridge fabricated by the students

Ishwar P. Sonar, Purva A. Joshi, Pallavi J. Rupnavar, and Pooja S. Bulbule

401

Abstract

Every year Alumni College of Engineering Pune (COEP) organisesstudents techno-craft competition for all undergraduate students for their innovative small projects. Considering strength properties of bamboo, a group of three girl students from second year civil engineering fabricated a proto-type of pedestrian bamboo bridge with reinforced concrete slab deck panel of width 1.5m and span 4.5m using the limited funds available in the competition held in year 2014-15. The model was tested for the live load and it was observed that bridge sustained the maximum load of crowd without failure of any member of the bridge. In short term loading case, maximum deflection shown by the bridge was within permissible limit. The project have demonstrated importance of bamboo as eco-friendly, economical structural material. Students received field experience on fabrication of bolted connections due to this project. Bamboo bridge of different configuration can be tried and there is lot of scope in research works in development of stiffness of bamboo bridges and techniques in improvement of durability of bridges.

43-T6

Elucidation on the application of principle of stationary potential energy method to structural analysis problems

V.K. ManickaSelvam and K.R. Bindhu

408

Abstract

43-T7

Design aid for rolled steel tension and compression members

AnkamreddiSatyaveni, V. Naveen kumar and Venkat Lute

412

Abstract

         

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