Is your house safe

9 March 2014 BARUAH DEVELOPERS &INFRASTRUCTURE PVT. LTD.

BARUAH DEVELOPERS & INFRASTRUCTURE PVT. LTD.

JORHAT

&

MAGNIDUS DESIGN PVT. LTD.NEW DELHI

presentunder their CORPORATE SOCIAL RESPONSIBILITY


ISYOURHOUSESAFE

CONSTRUCTION AWARENESS WORKSHOP # 2VENUE: C K B COMMERCE COLLEGE, JORHAT


What are the potential dangers ?


Natural Disasters Man-made Disasters

Economic Disasters Family Disasters


What is an earthquake ?



What does an earthquake do to your house?


Super-structure

(building)

Ground Level

Sub-structure

(foundation)


Framed Structure normal Framed Structure during an earthquake


TraditionalFramed Structures


Brazil


Japan


England


France


ModernFramed Structures


Steel (London)


Bamboo (Kengu Kuma - Beijing)


Bamboo (PT Bambu - Bali)


Paper (Shigeru Ban - Hannover)


Components of a Framed Structure


Frame

Infill


Framing Materials


RCC


Steel


Wood


Bamboo


Infill Materials


Brick


Gypsum Board


Paper


Bamboo and Paper


Bamboo Mat


WD wall Wattle & Daub


WD Walls


Finish

(optional)

Wattle

Daub


Fabian Ostner - Auroville


Advantages of WD Walls

Earthquake Protection monolithic tensile structure

Less Steel Requirement reduced load due to light walls

Cost Effectiveness locally available materials

Climate Comfort low heat absorption

Larger Room Sizes

Aesthetic modular construction


Some Common Construction Mishaps


Bending of steel reinforcement


Column thickness and clear cover being compromised


Unnatural riser heights


Inappropriate joining of beam to existing column


Presented byArup Deka, IITG

Importance of Earthquake resistant design

& Soil testing


Introduction





What are these buildings?What problems are associated with these buildings?Are they safe during earthquake ?Why are we still constructing them ?Can we do something about these buildings ?Is there any provision in our code?


What are these buildings ?

Cheaper and easily available construction materialsNot considered important enough during analysis and designOpen RC buildings.

Common buildings lack basic resistance to earthquake forces.

Codes do not stop us for doing so neither any encouragement

Building bye laws



This resistance can be achieved by following simple, inexpensive principles of good building construction practice. Adherence to these simple rules will prevent all damage in moderate or large earthquakes saves lifeThese simple rules are basicallyPlanning and layout of the building involving consideration of thelocation of rooms and walls.Lay out and general design of the structural framing systemStructures should not be brittle or collapse suddenly.Resisting elements, such as bracing or shear walls, must be providedevenly throughout the buildingBearing capacity of the soil should be checked properly as firm, Soft &Weak soil


Shear walls


Easy to constructStraight forward reinforcement detailsEffective in reducing costMinimize earthquake damage- structural & non structural elements


Buildings can be constructed on firm and soft soils Dangerous to build them on weak soils. Hence appropriate soil investigations should be carried outWeak soils must be avoided or compacted to improve them so as to qualify as firm or soft.For the purpose of making a building truly earthquake resistant, it will be necessary to choose an appropriate foundation type for it. The depth of footing in the soil should go below the level of shrinkage cracks in clayey soils. For choosing the type of footing from the earthquake angle, the soils may be grouped as Firm Soft & weak soil unless compacted and brought to Soft or Firm condition.




FAILURES DUE TO SOIL STRATA


Table 1: Physical Properties


Liquefaction, ground failure



Footings on sandy soils show immediate settlements whereas clays show long term settlements

Geotechnical investigation is a must for every site as soil is weakest material in the system and the failure is sudden and often leads to collapse

Rise in water table can reduce the bearing capacity significantly

clays are very stiff when dry but can become very soft when submerged

rise in water table can reduce the bearing capacity significantly

clays exhibits swelling pressures

place the foundation on firm soil


EARTHQUAKE HAZARD ZONES 2002

Zone V MM IX or moreMM VIII

Zone II MM VI

together now make Zone II MM VI or lessArea under the zones

V 12%IV 18%III ~27%

Table damageable ~ 57%

Bearing Capacity

calculation


dissolve or to weaken.Originally coined by Mogami and Kubo(1953)Commonly used to describe the sudden dramatic strength loss which sometimes occur in sand during seismic loading.It has been reported in many types of soil under dynamic loading


Assam EQ, June 12,1897(ML=8.7)


The danger of liquefaction at a site can be significantly reduced or eliminated by:DewateringIncreasing the in-situ densityMaking provisions to reduce the time required for relieving the excess pore water pressuresThese except dewatering ,may be best achieved by ground improvement techniques.

If the potentially liquefiable soil layer is located at the ground surface and is not thicker than 3.5m,the most economical solution may be removable and replacement with properly compacted nonliquefiablesoils.However, for liquefaction-prone soil layers located deeper than 3.5m from the ground surface, ground improvement techniques may be the solution


isolated footings poor (provide tie beams)

combined footings fair (provide tie beams)

raft foundations better

pile foundations best

Type of foundations and their seismic response


Building Codes For Engineered Construction

IS: 1893-2002 "Criteria for Earthquake Resistant Design of Structures,

Part I (Fifth Revision)" July 2002.

IS: 13920-1993 "Ductile Detailing of Reinforced Concrete Structures

subjected to Seismic forces - Code of Practice" November 1993.

IS: 4326-1993 "Earthquake Resistant Design and Construction of

Buildings - Code of Practice (Second Revision)" October 1993.

Many Good Books

Large Nos. of Conference Proceedings


ConclusionCarry out the engineering, architecture and planning measures

- Land use zoning.- Planning of habitat,- Implementation of building codes in all new constructions, and- seismic retrofitting of existing buildings and infrastructure.

Create the supportive structure of- public awareness,- education and training- research and development about the safety from earthquake hazard.

Appropriate policy, financial and institutional support at national andstate levels needs to be provided for putting this strategy into a workableaction plan.

Presentations & Public Speaking

Is your house safe