STRUCTURAL DESIGN FROM THE GREEN BUILDING PERSPECTIVE The need, and approach needed towards attaining sustainability GTCS

What is this green building??? Everyone seems to be talking about this….. a)A Building Painted Green is a Green Building ! b)A Building Constructed by a celebrity with High Cost is a Green Building c)It is a building where some things like rain water conservation, solar heating, solar power etc. have been done. d)A Green Building has something to do with energy ?. GTCS

A Green Building is A building where extensive study has gone into the analysis of the site, shape and orientation of the building, choice of materials, services and systems to ensure a happy time for the occupants while reducing the capital expenditure and the life cycle cost of ownership. GTCS

How does this have anything to do with structural design and concrete?? GTCS

To Answer this, we need to just REWIND and take a look at the building design process from the beginning GTCS

The PRIME MOVER of any construction is the BUILDING OWNER or PROMOTER, willing to spend money for a building to be made for a specific PURPOSE or FUNCTION GTCS

The Building is Designed by an Architect or Engineer to suit the owners’ requirements of space and function. GTCS

The Basic Design is forwarded to the Structural Designer for ensuring that the designed structure will stay safe, can be built safely GTCS

The Structural Engineer has to consider various inputs before he is able to complete his design and specifications, such as: 1.SHAPE OF BUILDING 2.SAFE BEARING CAPACITY OF THE SOIL 3.TYPE OF STRUCTURE :: STEEL / CONCRETE/ WOOD ETC. 4.LIKELY LOADING ON THE BUILDING OTHER THAN THE SELF WEIGHT 5.POSSIBLE FRAME DESINGS SUITED TO THE SHAPE AND LOADS etc… GTCS

This is the most important step at which a structural Engineer can think Green. Because basically thinking Green means thinking economy, safety and happiness for all GTCS

The TWO Aspects that a Structural Engineer can consider while initiating the design to lead to GREEN Thinking are:- LOADING DUE TO SELF WEIGHT MODE OF LOAD TRANSFER TO THE SOIL GTCS

LOADING (t/sqm) DUE TO SELF WEIGHT This is defined by the following : 1.Choice of construction system: Steel Frame Concrete Frame and type of slabs No Frame 2.Choice of construction materials: Type and Grade of Concrete and Steel Choice of superstructure materials GTCS

MODE OF LOAD TRANSFER TO THE SOIL This is defined by the following : 1.Choice of Framing System: Vertical Load transfer members Horizontal Load transfer members 2.Choice of spans in the frame: Material for framing Balance of economy between Slab thickness/ Beam dimensions and Column Dimensions GTCS

The Choice of the Framing is best left to the Structural Designer. But the Choice of Materials that determine the loading can be considered for making structures economical. Some superstructure materials which contribute to reducing the loading on buildings are: 1.AAC Blocks 2.CLC Blocks (Cellular Light Weight Concrete) 3.Foam Concrete in slabs GTCS

AAC Blocks GTCS

S.No.ParametersAutoclaved AeratedCellular LightweightBurnt Clay Bricks Concrete Blocks 1Basic raw materials & other inputsCement, Sand/PFA, High Quality Lime, Gypsum, Water & alluminium as aerating Compound Cement, Aggregate, Fly Ash, Water & Foam chemical Compound Top Soil & Energy 2General Properties Dry Density kg/m Compressive Strength in kg/cm – Range of applications / utilityLoad Bearing BlocksPartitionLoad-bearing & non-load bearing AgingNo gain in strength with age Gains strength with ageNo gain in strength with age Thermal Conductivity (W/m.k.) for 600 kg/m for 800 kg/m Sound InsulationSuperior than burnt clay & hollow concrete Normal Ease of WorkingCan be cut, nailed & drilled Normal ProcessCasting –rising –pre curing Casting –Rising- conventional curing Moulding-heat treatment. Comaprison of Properties of AAC Blocks with CLC and Country Bricks

3Shape & Form Pre-cast Brick size600 x 200 x 100/150/200 mm 230 x 100 x 70 mm Pre-cast elementsAny size of elements Not feasible Cast in shapeNot feasibleAny shape & size in any density Not feasible 4Water Absorption % by weight Less than 20% by volume12% for 800 kg/m3 density (by volume) 20% by volume 5Drying Shrinkage mm/meterShrinkage after maturing (for 600 kg/m3) (for kg/m3) 0.1No shrinkage 6ProductivityOutput 100% more than brick work Normal 7Eco FriendlinessPollution free, normal energy requirement, Open process uses fly ash or sand-lime Pollution free, Least energy requirement, Can consume fly ash around 33% Creates smoke, Uses high energy, Wastes agricultural land 8Structural saving due to dead weight reduction 55% reduction in weight of walls. Tremendous structural saving for high rise buildings in Earthquake / Poor soil area No additional saving 9DeliveryPre-Cured and ready for delivery Conventional curing required. Not ready for delivery in post production. Seasonal. 10AutomationAutomated manufacturing process- accurate design mix Semi automationManual

Some more superstructure materials which contribute to reducing the loading on buildings are: 1.Pre Cast Dry Wall Panels (AAC/ Calcium Silicate/ Fly Ash) 2.Hollow Core slabs 3.Composite construction (Steel joists encased in concrete) GTCS

For Structures where concrete is a main component, the structural designer has the definite choice of using upto 30% Fly Ash in cement for all applications: 1.PPC 2.Fly Ash Bricks 3.AAC Blocks 4.Pre Cast Dry Wall Panels (AAC/ Calcium Silicate) 5.Hollow Core slabs 6.Composite construction (Steel joists encased in concrete) In structures where there is no Urgency for de-shuttering, PCC is an ideal choice for Slabs and Beams also GTCS

How does the management of loading and choice of materials help in Green design?? GTCS

The structural design of a building ultimately emerges from the loading and type of design adapted. While using Fly Ash in concrete and cement based applications, the Structural Engineer Contributes to reducing the disposal of Fly Ash into the Environment. By itself, Fly Ash is a POLLUTANT. The only good use for Fly Ash, is in the building Industry. Use in cement, Blocks, Panels etc helps in large scale consumption of Fly ash without being detrimental to the Environment GTCS

The structural design of a building ultimately emerges from the loading and type of design adapted. By reducing the LOADING, natural results are reduction in the quantity of Steel, cement, water, aggregate and sand. This helps in reducing the embodied Energy consumed in a building. GTCS

Embodied Energy for any material is the ENTIRE energy that is consumed in the following processes: 1.Sourcing Raw Material 2.Manufacturing 3.Transportation to site 4.Converting the Material to Suit the site needs GTCS There is ENERGY Consumed at EVERY STEP. Same is the case with Cement, Sand, Aggregates and WATER

The structural design of a building ultimately emerges from the loading and type of design adapted. By adapting scientific methods like cut and bend, where the steel reinforcement is sized to suit the design requirements and delivered to site for immediate laying, there is considerable reduction in WASTAGE and HUMAN effort. GTCS

The structural design of a building ultimately emerges from the loading and type of design adapted. By clear identification and sorting of waste steel etc. on site and sending them for re rolling, there is the possibility of recycling in steel. This adds to the Savings in the Entire Energy consumed by the Building. Re rolled bars may not exhibit the same quality and strength as from virgin steel, but improvements can be made to raise the standards GTCS

The structural design of a building ultimately emerges from the loading and type of design adapted. Using the Appropriate DESIGN MIX CAN REDUCE the requirement of Steel Considerably. Adapting the appropriate methods of concrete mixing and pouring can also help in reducing consumption of raw materials. MOST importantly WATER. GTCS

The structural design of a building ultimately emerges from the loading and type of design adapted. Similarly adapting methods like POST Tensioning in Slabs can also contribute to the reduction in the consumption of Steel. GTCS

The structural design of a building ultimately emerges from the loading and type of design adapted. Adapting PRE CAST concreting technology, HOLLOW CORE Slabs etc. there can be a substantial reduction in the impact on the local environment. GTCS

The structural design of a building ultimately emerges from the loading and type of design adapted. Finally AND MOST IMPORTANTLY :: OVER DEPENDANCE ON STRUCTURAL DESIGN SOFTWARE CAN LEAD TO OVER CONSUMPTION. All design Codes are written as guidelines to be followed within the available technologies. The choice of right materials will enable the designer to arrive at more economical solutions using the same software. MANUAL checking of nodal loading and ultimate loads would be a good practice to identify over design. GTCS

A GOOD STRUCTURAL DESIGN WITH THE APPROPRIATE CHOICE OF MATERIALS AND TECHNIQUES CAN CONTRIBUTE TO ABOUT 3 POINTS DIRECTLY AND NEARLY AS MANY POINTS INDIRECTLY IN A GREEN BUILDING TRYING FOR CERTIFICATION. THIS SUMMARIZES THE ATTEMPT TO LOOK AT STRUCTURAL DESIGN FROM THE GREEN BUILDING PERSPECTIVE GTCS

A GREEN BUILDING COSTS UPTO 8% LESS THAN A CONVENTIONALLY DESIGNED BUILDING ELECTRICITY BILLS IN A GREEN BUILDING ARE 30% LESS THAN IN A CONVENTIONALLY DESIGNED BUILDING WATER REQUIREMENT IN A GREEN BUILDING IS 50% LESS THAN IN A CONVENTIONAL BUILDING HAPPINESS INDEX IS 200% MORE IN A GREEN BUILDING LIVING ENVIRONMENT AND WORK ENVIRONMENT IS FAR BETTER IN GREEN BUILDINGS GTCS

A CERTIFIED GREEN BUILDING IN KERALA WILL COST ONLY Rs 2500/- per sqft for standard specification buildings upto two floors. Land cost excluded. GTCS

OUR EFFORTS ARE DIRECTED AT IMPROVING AWARENESS 1.One of the biggest issues with any concept that appears to be the latest trend, is that the core issues and the basic fundamentals are lost out to hype and misconceptions. 2.All that appears green is NOT green. GTCS

THANK YOU GTCS