Presentation on theme: "RECENT TRENDS IN CIVIL ENGINEERING PRACTICES SUMITA DEY General Manager (Engineering) Mani Square Limited Kolkata 25 th September 2014."— Presentation transcript:
RECENT TRENDS IN CIVIL ENGINEERING PRACTICES SUMITA DEY General Manager (Engineering) Mani Square Limited Kolkata 25 th September 2014
PREAMBLE Civil Engineering is regarded to be the mother of all engineering. Although building homes, roads, bridges, sewerage etc. is as old as civilisation itself, we continually see new trends emerging. New thoughts, innovations and techniques are fast replacing age old practices and traditional methods of construction. Like in every other field, the real estate sector has also seen a number of such innovations and adoption of the state-of-the-art in construction techniques.
SOME RECENT INNOVATIONS
TALL BUILDINGS All over the world builders are starting to build higher and higher. In India, mainly in the metropolises, the skyline has risen. In Kolkata, due to a set of new building laws, builders have started to add floors to buildings already under construction. New buildings are being planned for heights hitherto unheard of in the city of Kolkata.
The structural engineer has to find ways and means to make the structure capable to withstand the additional loads, to reduce the loads or simply to make more correct assumptions and recalculate loads.
ADVENT OF SOFTWARE The advent of latest and powerful software and hardware take seconds to analyse the model of a huge multi-storeyed building. This makes innumerable iterations possible in no time.
REDUCTION OF LOADS AAC Blocks Air entrained autoclaved blocks are basically lightweight bricks. The specific gravity of these bricks are less than half compared to conventional clay or fly-ash bricks. Steel Floor Plates Extending an RC building by using steel columns/steel beams and a thin layer of concrete slab for buildings whose foundations and lower level columns have already been constructed.
REDUCTION OF LOADS (cont’d) RC Load Bearing Walls Walls may be designed as RC load bearing members. Use of aluminium formwork system like ‘Mivan’, in which 160 mm thick RC external and internal walls carry the loads. As a result… no columns, no beams and reduced slab thickness due to smaller panels.
What has made tall buildings possible in Kolkata where the sub-soil conditions are hardly conducive to weighty structures? Other than social and psychological barriers, Kolkata was probably missing the ‘structural’ atmosphere to build structures that would kiss the clouds.
SOME MORE RECENT INNOVATIONS
HIGH GRADE CONSTRUCTION MATERIAL For reinforcing steel, Fe 250 gave way to Fe 415, which made way for Fe 500. We now use Fe 550 or Fe 600. For concrete, M 15 gave way to M 20, which made way for M 25. The number after ‘M’ kept on increasing and reached the improbable figure of 70 i.e. M 70, which is quite common these days.
oCement (OPC)–360 Kg oFlyash–120 Kg o20 mm down aggregates–592 Kg o10 mm down aggregates–484 Kg oSand (Zone II)–718 Kg oWater–158 Kg (w/c ratio = 0.33) oAdmixture–2 Kg Strength at 7 days–32 to 36 MPa Strength at 28 days–45 to 49 MPa TYPICAL DESIGN MIX FOR M40 GRADE CONCRETE
METHODS OF SHUTTERING/STAGING AND DETAILING The ’Rail Climbing’ system have helped to increase the speed of construction manifold.
METHODS OF SHUTTERING/STAGING AND DETAILING In another system of staging, the props are left in place and only the shutters are removed.
METHODS OF SHUTTERING/STAGING AND DETAILING Use of couplers instead of lapping of bars has helped reduce congestion and wastage. It is also possible to have 100% lap at one place, as per code.
METHODS OF SHUTTERING/STAGING AND DETAILING Creation of safety platform has helped in enhancement of worker productivity by creating a psychological feeling that they are working at ground level. This has contributed to a large extent in increasing the speed of work.
CONCLUSION This presentation dealt with only a particular sector of Civil Engineering and some of the recent trends being adopted. Every day, some new technique is being introduced at some part of the globe thereby encouraging smarter designs, slicker structures, robust and safer construction practices. I have, however, scratched only the surface. Scores of innovations and modern techniques have come in vogue during the last decade, both in design and execution.