The Company lays significant emphasis on improvements in methods and processes in its areas of construction and operations. The Research & Development Division of the Company continues to enjoy recognition by the Department of Scientific and Industrial Research, Ministry of Science and Technology, Government of India. The primary focus of research is to continually refine the frequently used systems at our project sites to derive optimization, reduction in the breakdowns, improve effectiveness and efficiency of use and hence provide a competitive edge for any project with value Engineering.
1.Monitoring of Pile driving with Hydraulic Hammer
Monitoring of Pile driving with Hydraulic Hammer Pile driving analysis by hammer requires assessment of actual energy applied on pile top, which is conventionally based on applying hammer efficiency factors to the empirical equations. A study was undertaken at a site using Energy meter which was connected to the hydraulic hammer to convey vital information of actual hammer energy when it strikes the precast pile. This device will eliminate empirical parameters, and result in factual analysis for pile driving, and result in optimal hammer drop with fuel saving.
2. Real Time Monitoring of Diesel Generator Performance at Sites
Majority of fuel consumption at sites also emanate from running of Diesel Generators (DGs).Bearing this fact, areal time monitoring of DG sets is currently in progress using GEOHEMS software. This dedicated monitoring system is a part of all New CPCB II Compliance Generators and conveys information on useful diesel consumption,and targets wastage elimination. This monitoring is providing vital optimization information for DGs.
1.Phase wise Replacement of Energy Efficient Office Lighting System
At the Head Office, old fluorescent 36W tubes and bulbsare being replaced with LED tubes and bulbs. General working areas have been completely replaced with T822W LED tubes, while phase wise replacement in cabins and at Depot areas is currently in progress.
1. Use of Polymer Slurry for installation of High Capacity Bored Piles in Sandy Sub-soil Environment
At a construction site near Delhi, high capacity piles were desired, since the number of piles was restricted due to alimited footprint area of structure. Three dedicated load testswere performed on 1000mm diameter piles installed using polymer slurry. To increase the unit weight of the polymer,a commercially available supplement Alfabond was added along with fine sand. A gravel pad was also deployed at the bottom of the bore for improving base resistance. All three piles gave safe capacity excess of 750MT against a normally achieved value of around 500MT with conventional piling procedure. These trials proved significant improvement in frictional capacity using polymer slurry, paving way for economic pile foundation applications.
2. Special Concrete for soft Piles
Secant piles are overlapping combination of soft and hardpiles constructed in an array. In a project site near Delhi involving such piles, a special concrete mix design exercise was undertaken to ensure low strength for initial 7 days while still retaining a desired strength of 20MPa at 28 days. Exercise for trial concrete mixes was undertaken using more than fifty different proportions involving retarders and flyash, while still maintaining required work ability for piling concreting. Amix was devised that could achieve a 9-12MPa strength at 7days, while maintaining a desired 28 day strength of 20MPa.This concrete mix design exercise is expected to minimize to great extent cutting of concrete during boring for adjacent hard piles in the construction of Secant pile wall.
3. Top Down Construction – Special Adaptations
Top down technique which allows simultaneous construction of sub- and super-structures has been used for metro stations,multi-level car parking and commercial complexes. New adaptation in the process of Top Down technique used at Wadala site at Mumbai, were undertaken to account for variations in rock level encountered. This technique involved bored pre-cast piling, which, subsequently doubled up as a pre-cast column for the basement. To address variations in rock levels, a plate was fitted at the bottom of precast column to which a structural member with enveloping reinforcement cage was welded later. After lowering the column, the annular portion at the bottom could be concreted in situ. This facility ensured precast column of a standard length and could address variations in rock levels.
4. Tunnel Boring Machine for Tunneling through Mixed Soil and Rocky Strata
For a project of MRTS for DMRC in Delhi, MIXED SHIELDEPB TBM Machine is utilized for tunneling through mixed soiland rocky strata with great success.
5. Spun Pile Driving and Strength Gain Characterization
Spun piles have been introduced in India very recently,and over 1700 such piles had been driven by the Company at a site. These piles were 600mm diameter and driven in two segments, each of 12m length. To have assessment of strength gain in Spun piles, 50 piles were subjected to End of the Initial Driving (EOID) monitoring through Dynamic tests. This furnished pile capacity immediately after driving. Of these, about 14 piles were subjected to Re-strike test to determine capacity after a rest period of 14 and 21 days. With these tests, a Setup factor was determined which confirmed that there isa strength gain in pile by at least 2.5 times after initial driving. The Set-up factor is to be a valuable tool for all future operations to determine long term pile capacity,since EOID tests are easier to conduct.
6. Anchor Plates at JNPT Site
Ground improvement work is currently in progress at a site using Pre-fabricated Vertical Drains (PVDs).Conventional 2-piece spot welded MS anchor plates were initially used for anchoring PVDs, which comprised spot welded handle. This anchor used to rust and the handle broke frequently during field operations, thus inviting reworking through welding. This problem was alleviated by devising a slitted type anchor plate extruded from a single plate and prepared from tool die.With this measures, excess of 2 lakhs PVDs have been successfully installed without any problems. Apart from smooth operations, the price of this new product was less than 50.76% compared to its erstwhile counterpart.
7. Stationery Slow Crane for Muck removal
An in-house stationery slow crane was fabricated and assembled using available winch and structural steelelement for Muck Removal at Box Pushing Project with good success in saving cost and utilization of usable resources. This practice is being extended to other project as practicable.
8. Cement Saving by using Primer Additives for Concrete Pumping Operation
A study is currently under progress for cost-effective replacement of cement based slurries during priming operations of Concrete pumps or Boom placer.Currently, proportions for preparing priming cement slurry is 300 Kg of cement + 700 Kg of Sand + 1100 lit of water. Studies are currently underway using anionicpolymer additive as a cost-effective replacement of cement slurries from priming. Polymer slurries are known to create a thin lubricating film inside concrete pump, hoses and pipe lines and reduce friction while also preventing blockages. Outcome of this study is expected to save cement cost, particularly for project swhere mass concrete volume is expected.