Central Building Research Institute Research Articles

Innovative multi-setup modal analysis using random decrement technique: a novel approach for enhanced structural characterization

PurposeThis paper introduces a novel multi-setup merging method and assesses its performance using simulated response data from a Finite Element (FE) model of a five-storey frame and experimental data from a cantilever beam tested in a laboratory setting.Design/methodology/approachIn the research conducted at the Central Building Research Institute (CBRI) in Roorkee, India, a cantilever beam was examined in a laboratory setting. The study successfully extracted the modal properties of the multi-storey building using the merging technique. Identified frequencies and mode shapes provide valuable insights into the building's dynamic behavior, which is essential for structural analysis and assessment. The sensor layout and data merging approach allowed for the capture of relevant vibration modes despite the limited number of sensors, demonstrating the effectiveness of the methodology.FindingsThe results show that reducing the number of sensors can impact the accuracy of the mode shapes. It is recommended to use a minimum of 8 sensor locations (every two floors) for the building under study to obtain reliable benchmark results for further evaluation, periodic monitoring, and damage identification.Originality/valueThe results demonstrate that the developed algorithm can improve the system identification process and streamline data handling. Furthermore, the proposed method is successfully applied to analyze the modal properties of a multi-storey building.

Performance evaluation, energy conservation potential, and parametric study of borehole heat exchanger for space cooling in building

A building integrated Borehole Heat Exchanger (BHE) has been designed and installed at Central Building Research Institute, Roorkee (29.87°N 77.88°E) India. The thermal performance and energy conservation potential (cooling potential) of installed BHE have been evaluated during summer months in the year 2013. The parametric study has also been done for its maximum performance. Quantitative assessment of CO2 mitigation has also been computed. The constant BHE water temperature (approximately 25 °C) witnessed the transferring of heat from air to water and vice-versa. It is found that the air temperature is reduced by 8–13 °C during summer season at air velocity of 18.9 m/s from the inlet of the BHE (exit of blower), whereas outdoor temperature was recorded as 35–39 °C. This system is capable of maintaining room temperature between 26 and 30 °C during peak summer season. The cooling capacity is evaluated between 150 and 180 kW h. BHE integrated with building can significantly reduce the 39836.25 kW h of electrical power needed for space cooling load and it can reduce global warming by substantially mitigating the carbon-dioxide to the tune of 50.10 tonnes annually. During the parametric study, it is found that double U-tube, circular pipe with optimum pitch of 4 in. is needed to achieve higher performance from the BHE.

Composite materials from local resources

An overview of building materials from local resources is briefly presented with a particular attention on natural fibres based composites. Natural fibres are low-cost, locally available in abundance and obtained from renewable resources. At the Central Building Research Institute, Roorkee, the potential of sisal and jute fibres as reinforcements have been systematically investigated to overcome their well-defined problems of moisture absorption. The performance of polymer composites made from these natural fibres and unsaturated polyester/epoxy resin was evaluated under various humidity, hygrothermal and weathering conditions. Consequent to this, various composite products such as laminates/panels, doors, roofing sheets, shuttering and dough moulding compound have been prepared. The suitability to these products is assessed as an alternate material according to the existing Indian standard specifications. The process know-how for the manufacturing of natural fibre composite panels/door shutters has also been commercialized.

Estimation of source parameters of Chamoli Earthquake, India

The devastating earthquake (mb = 6.6) at Chamoli, Garhwal Himalaya, which occurred in the morning hours on 29th March 1999, was recorded on Delhi Strong Motion Accelerograph (DSMA) Network operated by the Central Building Research Institute, Roorkee. In this paper the source parameters of this event calculated from the Strong Motion Data are presented. The seismic moment for this event has been found to be of the order of 1025 dyne.cm and the moment magnitude has been calculated in the range of 6.53–6.69 at different stations. The stress drop and source radius for the earthquake are also calculated.

Building materials for low-cost housing

This paper commences from where the previous paper ends. It provides an insight into the present scenario of R&D being pursued in India partially with the perception presented by the previous author. The paper not only presents the state of the art of R&D in the ongoing programme in the Central Building Research Institute but also provides a national overview of the ongoing efforts in search of new building materials from wastes, from alternative resources to complement and substitute the traditional building materials where they are in short supply for housing programmes.

Role of voluntary organizations in low-cost housing

The author, a former Director of the Central Building Research Institute, Roorkee, who is now a committed member of a voluntary organization, has emphasized not only the necessity but has suggested ways and means of including the intellectual and other resources of these organizations into the shelter programme. His active association with voluntary organizations indicates the level of intellectual resource available to such agencies, which is the rule rather than exception for most NGOs now operating in India.

Roofing finishes

Scientists at the Central Building Research Institute, CBRI, at Roorkee conclude, in a detailed study as part of their normal research programme, that good‐quality roofing tiles possessing adequate breaking strength and durability can be produced from properly blended and processed clay, either on a potter's wheel or on a tile‐moulding table.

Disposal of solid wastes—red mud and fly‐ash in the production of heavy clay products

With the rapid industrialisation and growth progress in India, huge quantities of industrial and agricultural waste materials are accumulating every year; they are finding limited use and are therefore causing a severe disposal problem, besides health hazards affecting the ecology of the country. About 20 million tonnes of fly‐ash and 2 million tonnes of red mud are annually obtained from thermal power plants and aluminium industries, respectively. Investigations of the use of such industrial wastes for the production of heavy clay products have been extensively undertaken at the Central Building Research Institute, Roorkee and the results attained have been reported in the paper.

Stabilized soil in brickmaking

This article from the Central Building Research Institute, at Roorkee, India, reviews experiences from several countries in the use of stabilized soil for building, pointing out that results from this technique in road works could be extended to the production of bricks and blocks made from stabilized soil. However, there are many different kinds of soil, each requiring careful examination before deciding on the appropriate method of stabilization.

Direct electric curing of in situ concrete

Reviewing the uses of accelerated curing of concrete, this article from the Indian Central Building Research Institute at Roorkee notes that various forms have been used, but mostly for precast work. Attention has now focused on rapid curing of in situ construction, and this paper presents the results from direct electric curing, which has proved to be more economical and to consume less energy than other methods. An appendix outlines the finite element method formulation used to decide the number of electrodes required and their distribution pattern within the concrete.

Slim precast stone blocks for masonry

The relative absence of code guidance on stone masonry walk prompted the Central Building Research Institute at Roorkee, India, to devise a method of using stone spalls in precast blocks 100–200 mm thick for a new wall construction system. Now being widely used in projects throughout India, the system is a labour‐oriented precast process requiring little capital investment, very attractive to developing countries. Tests and application results are discussed in this paper.

Simple Prefabrication Proves its Worth

Reporting a user-reaction study of low-income dwellings near Delhi, the author, who is an architect with the Central Building Research Institute, Roorkee, presents evidence to show the general superiority of the Holopan System dwellings over the traditionally-built dwellings with similar specification on the same site. This type of simple prefabrication is advocated as an appropriate technology for mass housing in developing countries.

Agro-Industrial Wastes in Brickmaking

This review from the Central Building Research Institute, Roorkee, India, describes test and field manufacture results from using particular soils mixed with rice husk, rice husk ash, fly ash and cinder for brickmaking. Optimum-proportion admixtures of the wastes, depending on material characteristics, and firing at 1000 ± 20 °C in continuous kilns, have produced bricks of 50–225 kg/cm2 compressive strengths. Fuel savings in firing of up to 25 per cent can also be achieved.

Influence of phosphate pretreatment on durability of zinc‐rich paints

Corrosion protection efficiency of any protective system depends not only on the nature and quality of the coating system used but also on the condition of the mrface on which it is to be applied. Various metal cleaning methods include (a) chemical cleaning — solvent degreasing, alkali cleaning and acid pickling (b) mechanical cleaning — shot blasting and (c) chemical conversion coatings — phosphating. Several of the recent advances in the field of prepaint treatment of steel have had as an objective the provision of an intrinsically fine, compact, well adhered zinc phosphate coating. Studies in this direction have been carried out in Central Building Research Institute, Roorkee and conditions for a suitable phosphating process have been optimised. Some work on the development of zinc rich paints based on both inorganic as well as organic binders have already been reported. The study has been extended by evaluating the performance of these zinc rich coatings on phosphated steel panels. In this report the performance of the above mentioned coatings when applied on the phosphated steel panels have been discussed. The studies reported include the preparation of the phosphated mild steel panels having three levels of coating wight ranging between 1.5–7.5 g/m2 (obtained by varying only the immersion time and keeping other parameters similar). A cost of zinc rich paint (75m?) based on either sodium silicate or chlorinated rubber binder was then applied on these panels along with the unphosphated ones. Comparison of the corrosion protection efficiency of the various systems thus obtained was carried out by using both laboratory and accelerated laboratory tests as well as by outdoor exposure studies. The performance of the coatings on phosphated panels has been remarkedly satisfactory as compared to the unphosphated panels. This is particularly so when the coating weight of the phosphate layer is between 4.5–7.5 g/m2; there is not any marked difference in the performance of paints applied on a phosphated layer with a coating weight of about 1.5 g/m2 as compared to the unphosphated panels.

Bored compaction piles

Cast in-situ bored piles of a special type developed at the Central Building Research Institute, Roorkee, India, have proved particularly useful for loose soils with a high water table as well as in other situations. Their construction and applications are described in this article. Professor Mohan, who is Vice-President of CIB, is director of the Institute, where G. S. Jain is scientist co-ordinator and M. P. Jain is a research scientist.

Lime blowing in bricks

The problem of lime bursting in brick manufacture is acute in some parts of India and elsewhere — fired bricks turn into powder when exposed to the atmosphere, due to the presence of lime particles. Work at the Central Building Research Institute, Roorkee, has concentrated on the mechanism by which chlorides can prevent this.

Movable roof insulation in hot climates

This paper presents the results of experiments on the effect of a system of movable insulation – with and without a roof pond – on temperature and heat flow at the ceiling surfaces of air conditioned and unconditioned rooms in buildings roofed with thick reinforced concrete which are exposed to extremes of hot and cold weather. Results indicate that there is considerable merit in adopting such a system, particularly in hot, dry conditions, in addition to the limited benefits of harnessing solar energy in winter conditions. The experiments were carried out at the Central Building Research Institute, Roorkee, UP, India. Mr Rao is at present working as an associate professor in the Department of Building Science, Faculty of Architecture, University of Singapore.

Preparing a national schedule of rates and specifications

Wide variations in the description of similar items, the units adopted, methods of measurement and in the provision of basic data between one region and another lead contractors to include costly safeguards in their tenders for public works, argue the authors in this paper presented at a symposium on ‘Standardisation in Construction and Buildings’ held at Roorkee, UP, India last year, sponsored by the Civil Engineering Division of the Institution of Engineers, India, and the Central Building Research Institute, Roorkee. The work of preparing such a standard schedule has now been undertaken by the National Buildings Organisation, and the authors briefly outline the methodology adopted.

Housing needs at the subsistence level

The problem of housing is most acute when the users belong to a very low income group who cannot pay for the houses they occupy. Intuitive solutions aggravate the problem to a further degree. An investigation by three researchers of the Architecture and Physical Planning Division, Central Building Research Institute, Roorkee, India, outlines how the users' actual requirements can be discovered and then interpreted for arriving at economic planning solutions.

Manufacture of Building Bricks by a Semi-Mechanized Process

In view of the heavy capital investments and expenditure of foreign exchange involved in importing each of the fully mechanized brick making plants established in the country in recent years, a project was undertaken at the Central Building Research Institute to design and develop indigenously a semi-mechanized brick making machine suitable for making wire-cut bricks from alluvial days. The machine has been developed primarily to meet the pressing demand for such a machine from the small scale producers of building bricks.In this paper, the main features of the machine, its output, operation, etc. have been described and an estimate presented on the capital outlay for a plant producing about 7 million bricks per annum. A break up of the estimated cost of production is also given.