credai - confederation of real estate developer's

Dear Distinguished Members!

NEW YEAR 2013 may bring you all HEALTH, WEALTH and PROSPERITY.As the year 2012 passes by, we are left with mixed feelings.

The sale of apartments, were encouraging and dull in phases.

The availability of sand was a major issue, due to which Construction Industry came to a standstill.

Issues related to service tax remain unresolved.

However on the positive side, we achieved major relief from the government to have our plans sanctioned at GVMC itself, avoiding the procedure of LRS, thereby saving considerable time and interest on investments.

From CREDAI Visakhapatnam a good team of Delegates represented the 12th CREDAI NATCON at Barcelona, Spain on 30th Sept, 1st & 2nd Oct.2012 and their presence at the event left an impression on CREDAI Visakhapatnam in National level. It was an wonderful occasion for Builder Community.

All our Members should be happy having involved through their contributions that the Registration for our own Office Premises has been registered on 9th Nov. 2012 and the work on construction is in good progress.

I am sure that the year 2013 would be definitely be more encouraging and profitable in all respects.

While wishing you all for your all round Prosperity in the New Year 2013, I profusely thank each every Member of our Association for their all round support and cooperation to the Team of CREDAI Visakhapatnam during the year 2012.

I once again wish you all, successful ventures in the New Year 2013.Regards,

(B. RAJA SRINIVAS)

President.

credia visakhapatnam 5

Credai urges MPs to Consider real estate reforMs

Mumbai: Real estate developers’ association, Credai today urged lawmakers to consider reforms in the real estate sector to boost growth.

In a letter to MPs, Confederation of Real Estate Developers’ Association of India (CREDAI) national president Lalit Kumar Jain said: “Though the government is moving in right direction with bold reforms agenda, much more can be achieved without any controversy or incurring additional cost just by focusing on the housing sector.”

He has also mentioned a 10-point action

plan drawn up by Credai to rejuvenate the sector.

“This action plan will help the economy to grow at much faster rate since realty contributes to the growth of over 200 other industries. Real estate is highly capital and labour intensive which makes it the largest employer after agriculture,” Jain said.

The association added that there are some shortcomings in the proposed Land Acquisition and Real Estate Regulatory Bills which are likely to be moved in the ongoing session of Parliament.

“The bills appears to be one-sided as they seek to punish errant developers while ignoring defaulting buyers and corrupt officials.

(While provisions) in the Land Acquisition Bill may make housing costlier,” the letter said.

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real estate seCtor seeks More tiMe to CoMPlete ProjeCts for tax benefit

The real estate industry has requested the Government to extend the computation period for availing itself of income tax benefits by one more year. This period is going to end on March 31, 2013.

The industry’s apex body National Real Estate Development Council (Naredco) has written a letter to Prime Minister Manmohan Singh. The real estate industry gets benefit under Section 80-IB (10) of the Income Tax Act 1961. This is a sunset clause where extension was given in 2010-11 keeping global recession in mind.

According to the revised provision, a developer will be eligible for 100 per cent deduction in respect of profit from those housing projects where approval from a local authority has been obtained between April 1 2005 and March 31, 2008.

The developers were given five years to complete the projects. It means that this

benefit will be given only if a project is completed on or before March 31, 2013.

However, Naredco President Navin Raheja, in his letter to the Prime Minister, appealed to extend the completion period of projects sanctioned on or after April 2005 from five years to six years. He felt that the deadline of March 31, 2013 specified for completion of projects, to qualify for concessions entitled under said the Act, would be difficult to realise due to reasons beyond their control.

Raheja said that the liquidity crunch, high cost of funds, high mortgage interest rates, followed by further slowdown in economy after 2010 and high inflation have impacted demand as well as supply. Availability of labour has gone down drastically due to MGNREGA, impacting progress of ongoing projects, he said.

“Increase in cost of construction materials primarily cement and steel and labour have jacked up the prices. The Punjab

and Haryana High Court decision to ban use of underground water for construction in Gurgaon and Haryana Government’s inability to supply piped water have slowed down construction,” he said.

AFFORDABLE HOuSING

Earlier in its national convention, the industry body also pitched for making affordable housing a priority in urban planning. The theme of the two-day convention was sustainable housing for masses. It was inaugurated by President Pranab Mukherjee.

The convention recommended that holistic urban planning, which would include a focused effort towards affordable housing, would be imperative if India is to address the 18.78 million household urban housing shortages.

It also highlighted that optimal utilisation of land, especially of Government-owned land parcels, could improve land availability for real estate developers.

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credia visakhapatnam8

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low-Cost housing: builders Can now taP overseas funds

nThe Reserve Bank of India has opened up the External Commercial Borrowing (ECB) route to give a fillip to low-cost affordable housing projects.

nThe central bank has allowed developers/ builders to tap the external commercial borrowing (ECB) route for low-cost affordable housing projects.

nHousing Finance Companies (HFCs)/ National Housing Bank (NHB) can also use the ECB route for financing prospective owners of low-cost affordable housing units.

nDevelopers/ builders as well as HFCs and NHB can tap the ECB under the approval route.

nA low-cost affordable housing project for the purpose of ECB will be a project in which at least 60 per cent of the permissible floor space index would be for units having maximum carpet area up to 60 square meters.

nSlum rehabilitation projects will also be eligible under the low cost affordable housing scheme, the RBI said in a notification.

nThe RBI said ECB proceeds can be utilized only for low cost affordable housing projects and not for acquisition of land.

nBuilders/developers meeting the eligibility criteria will have to apply to the NHB, which will act as the nodal agency for deciding a project’s eligibility as a low cost affordable housing project.

nOn being satisfied, NHB will forward the application to the Reserve Bank for consideration under the approval route.

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Sewage treatment plant (STP) plays vital role in the process of removing the contaminants from sewage to produce liquid and solid (sludge) suitable for discharge to the environment or for reuse. We know that 75% of the world’s fresh water resources are contaminated, the remaining is fast disappearing. Waste water is produced from toilets, baths, showers, kitchens, sinks, and so forth that are disposed of via sewers.

WHY SEWAGE TREATMENT PLANT

One question that many people might

sewage treatMent Plant in aPartMent CoMPlex for wastewater treatMent

ask is, “Why not simply dump this wastewater onto the ground outside your home, or into a nearby stream?” If you release wastewater directly into the environment, things get very smelly very fast. Human waste naturally contains bacteria that can cause disease. Once water becomes infected with these bacteria, it becomes a health hazard. The increased algae, reduced oxygen and murkiness destroy the ability of a stream or lake to support wildlife, and all of the fish, frogs and other life forms quickly die. That’s why communities build

wastewater treatment plants and enforce laws against the release of raw sewage into the environment.

STAGES IN SEWAGE TREATMENT PLANT

Pre-treatment: Pre-treatment removes materials that can be easily collected from the raw wastewater before they damage or clog the pumps and skimmers of primary treatment clarifiers. The influent sewage water is strained to remove all large objects carried in the sewage stream. This is most commonly done with an automated mechanically raked bar screen in modern plants serving large populations, whilst in smaller or less modern plants a manually cleaned screen may be used.

Primary Treatment: Conventional sewage treatment may involve three stages, called primary, secondary and tertiary treatment. Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment.

Secondary Treatment: Secondary treatment is typically performed by indigenous, water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment. Secondary treatment removes dissolved and suspended biological matter.

Tertiary Treatment: Tertiary treatment


is effected by sand filters, mechanical filtration or by passing the effluent through a constructed wetland such as a reed bed or grass plot. Tertiary treatment is sometimes defined as anything more than primary and secondary treatment. Treated water is sometimes disinfected chemically or physically (for example by lagoons and micro filtration) prior to discharge into a stream, river, bay, lagoon or wetland, or it can be used for the irrigation of a golf course, green way or park. If it is sufficiently clean, it can also be used for groundwater recharge or agricultural purposes.

SLuDGE TREATMENT

Sludge produced by sewage treatment is organic in nature and contain useful amounts of plant nutrients such as nitrogen, phosphorus and essential trace elements. The first objective should be to utilize the sludge as a fertilizer or soil conditioner on agricultural land. Sludge is treated using a variety of digestion techniques, the purpose of which is to reduce the amount of organic matter and the number of disease-causing microorganisms present in the solids. The most common treatment options include anaerobic digestion, aerobic digestion, and composting.

Anaerobic digestion generates biogas with a high proportion of methane that may be used to both heat the tank and run engines or microturbines for other on-site processes. In large treatment plants sufficient energy can be generated in this way to produce more electricity than the machines require. Anaerobic digestion is a bacterial process that is carried out in the absence of oxygen.

Aerobic digestion is a bacterial process occurring in the presence of oxygen. under aerobic conditions, bacteria rapidly consume organic matter and convert it into carbon dioxide. Once there is a lack of organic matter, bacteria die and are used as food by other bacteria.

Composting is also an aerobic process that involves mixing the wastewater solids with sources of carbon such as sawdust,

straw or wood chips. In the presence of oxygen, bacteria digest both the wastewater solids and the added carbon source and, in doing so, produce a large amount of heat.

ROLE OF BACTERIA

In the typical sewage treatment plant, oxygen is added to improve the functioning of aerobic bacteria and to assist them in maintaining superiority over the anaerobes. Aerobic bacteria require oxygen for life support whereas anaerobes can sustain life without oxygen. Facultative bacteria have the capability of living either in the presence or in the absent of oxygen. Microorganisms and their enzyme systems are responsible for many different chemical reactions produced in the degradation of organic matter. As the bacteria metabolize, grow and divide they produce enzymes. These enzymes are high molecular weight proteins. All treatment plants should be designed to take advantage of the decomposition of organic materials by bacterial activity.

Sewage Treatment Plant is becoming ever more critical due to diminishing water resources, increasing waste-water disposal costs, and stricter discharge regulations that have lowered permissible contaminant levels in waste streams. Effective waste-water collection and treatment are of great importance from the standpoint of both environmental and public health. In recent years, there has been growing interest in waste-water reuse as a major component of water demand management.

RECOMMENDED SEWAGE TREATMENT PLANTS FOR APARTMENTS

Sewage Treatment plant system can be opened or fully sealed. Some apartments adopt partially sealed system. One of main disadvantage of opened or partially sealed system is sewage is broken down by bacteria and during this process methane is released into campus or at ground floor level. The gas released from sewage chamber due to biological

processing (by bacteria) will contain methane. Methane is highly combustible and toxic.

Sewage Treatment Plant with opened or partially closed is not recommended for apartment or densely populated areas. In this system smell can be sensed for miles. This system is only useful for large sewage treatments. For small residential units a completely sealed package unit is recommended. Sewage compartments with methane gas should be located away from car parking or area that can cause ignition or spark. Any ignition or spark can easily catch fire in sewage compartments with methane gas.

For apartments or for small residential units, automated system is recommended as this will reduce maintenance cost. Disadvantage of manually operated system is, there are chances of human error of dry running the pumps or not starting pumps in time. This can result in machinery breakdown or overflow of sludge. Automated system helps to prevent breakdown or over flow and association can save more than Rs 15000 per month on maintenance cost. Manually operating system is cheaper to install comparing to automated system but cost of maintenance is higher when comparing with automated system. The system release methane. This is supposed to be in sealed chambers and then released at a point few meters above the tallest point of the building. This should be taken care while designing sewage treatment plant for apartments or high-rise. In Metropolitan cities and urban areas, sewage treatment plant or mini sewage treatment plant is mandatory for getting a new water connection.


Celebrations of annual faMily PiCniC held on 30th deC 2012 at Chilukuri brindavan estates

entrance

reception

aCtivities of Children, ladies in gaMes, sPorts and danCe

actor sunil

singer & anchor geeta Madhuri

gathering


gift by geeta Madhuri to rajesh family

gift by sri k.s.r.k raju (sai)

gift by sri kanti sekhar

gift by sri b. srinivas

gift by sri M. satish

gift by sri P. bhogeswara rao

sri P. koteswara rao

Chairman honouring sri Cs reddy Credai aP

bumper Prize scooter Presentation

sri k.s. Chandran adresssing


sri C. srinivas, Chilukuri brundavan estates being honoured by sri C.s. reddy, President Credai a.P group Photo of executive body with sri C.s.reddy

President Credai a.P

enjoying lunch

Children enjoying

action Photos of 8th general Meeting held on 3rd dec 2012

P. bhogeswara rao adressing

a Cross section of gathering

another Cross section of gathering

sri P.v.l.n raju rendering vote of thanks

sri M.v.v. satyanarayana Chairman presenting memento to Zuari Cement’s executive


Whether you call it smart plumbing, green plumbing or plumbing biospherics, the concept is the same: the reduction of water use through resourceful landscaping, wastewater technology and high-efficiency plumbing design. If you are applying for Leadership in Energy and Environmental Design (LEED) certification for your building, such environmentally friendly plumbing could help you meet requirements in several point categories, including materials and resources, energy and atmosphere, water efficiency, sustainability and innovation in design. Even if you aren’t seeking LEED

certification, here are six ideas that are worth considering because they go a long way in protecting our natural resources.

1. WATER EFFICIWENCY

The goal of water efficient plumbing is to reduce potable water use, thereby putting less of a pull on the Edwards Aquifer system. The current LEED reference guide allows points for a 20 percent reduction in time of each use for automatic motion-control or metering sensors on lavatory

and sink faucets. A second point is allowed for a 30 percent

reduction.

At the very least, fit all sink and lavatory faucets and

showers with water restricting aerators.

Go one s t e p further by

replac ing y o u r

plumbing fixtures with low flow and ultra-low flow versions. Most low-flow faucets limit flow to 1.8 gallons per minute, meeting the base design requirements for LEED (2.5 gallons per minute). Others use sensors to limit the amount of time the water runs, resulting in tremendous water savings up to 70 percent less than manual faucets. By shutting off during the lather cycle of 20 seconds (according to u.S. Food and Drug Administration’s recommended hand-washing procedures), sensor-operated faucets can save as much as a gallon of water each use.

You can also increase water efficiency by looking at how you irrigate. using drip hoses or sprinkler systems that are automatically timed and programmed to turn on or off based on ground soil moisture also contribute to a reduction in water use.

2. WASTE REMOVAL

Nobody really wants to talk about it, but how we get rid of waste is a big -- well -- water waster. Instead, use a low-flow (using 1.2 gallons per flush) and ultra-

low flow (0.8 gallons per flush) toilet. Or choose a dual-flush

toilet that has two levers -- one for urine (one gallon per flush) and one for solid waste (1.6 gallons).

If you’re feeling really brave, try a waterless system such as a non-water urinal. Such systems are gaining in

popularity around the world

advanCes in PluMbing teChnology helP builders add leed Points


-- from California elementary schools and football facilities to the Taj Mahal and South Pole. Just this year, two such systems won the 2006 Award for Design Excellence with their sleek, efficient design.

A water-free urinal uses a cartridge that eliminates odor and the need for water. Inside the cartridge, the chamber retains a small amount of liquid waste while the rest drains down the sewer. A lighter-than-water sealant floats on top of the trapped waste, creating an airtight barrier and keeping odor from escaping. When urine is added, it passes through the sealant, displacing the waste already there. The sealant then emulsifies to recreate the barrier. There is no flushing.

Last March, Randy Goble, director of marketing communications at Falcon WaterFree Technologies of Grand Rapids, Mich., told Wired magazine that if just 10 percent of flush urinals were converted, some 200 billion gallons of water would be saved each year.

3. WATER COLLECTION

Storm water capture, storage and use systems collect rainwater and reuse it in the building’s non-potable water fixtures, such as landscape, toilets and fire suppression storage. However, because the system requires two plumbing systems, it is best suited for new construction in areas where rainfall is substantial.

4. WATER HEATING SYSTEMS

Texas’ sunny, dry climate is good news, however, for solar water heating. Nationwide, heating water uses up approximately 18 percent of energy used in homes and 4 percent in commercial buildings. An alternative is a solar water heating system, which uses the sun’s energy rather than electricity or gas to

heat water. Such systems have been shown to provide up to 80 percent of the hot water needs. Newer systems are being developed that use bio-diesel fuels and wind.

On demand systems can also help meet requirements for reduction in water use through the installation of hot water recirculation systems that reduce the amount of water wasted down the drain while you are waiting for hot water to

reach the fixture.

Sustainable systems

Building sustainability and indoor environmental quality equate to 45 percent of LEED credits. Epoxy pipelining may well qualify as the case can be made that its technology adds life (as much as 50 years) to an existing pipe system, reduces landfill debris, increases the sustainability of the building and improves water quality.

Based on research developed by the u.S. Department of Defense after several Naval facilities had to be closed because of poor water quality, epoxy pipelining entered the mainstream. using an

advanced mixture of polymers (or large molecules) that form a product that is harder than most metal when combined, epoxy adheres to surfaces and bonds in such a way that it keeps contaminants from building up and breaking through the protective barrier it forms. As such, pipe leaks are fixed and future corrosion stopped.

Conserving other energies

There are ways plumbing can contribute to the overall efficiency of green buildings by using water to conserve energy in other areas. The most common is designing a plumbing system for green roofs. In Texas, such irrigation systems are critical in the early stages of growth or if you aren’t going to use drought-resistant plants. Design options help keep water on the roof through restricted drain systems or utilize grey water or purple pipe systems for irrigation, as a couple of examples. In turn, green roofs help conserve energy as well as reduce storm water runoff and the urban heat island effect.

We consume some $4 billion a year in energy costs associated with pumping, treating, delivering, collecting and cleaning water. Doesn’t it make sense to slow

down our use? Widespread adoption may mean that next year we can continue to water our lawns through the summer.

But more important than green grass is the ability to design

“WHOLE BuILDING” plumbing systems that preserve, protect and respect our environment.

Resources

? Texas Water Development Board publication, Texas Manual on Rainwater Harvesting, Third Edition, published July 2005; available online at www.twdb.state.tx.us/publications/reports/RainwaterHarvestingManual_3rdedition


Credai will hold a skill development programme for 10,000 workers in the construction field in AP.

Kakinada, Nov. 19:

The union Government should consider waiving service tax on houses in the non-luxury segment, especially for the lower middle classes and low-income groups in the society, according to C. Sekhara Reddy, President of the AP Chapter of the Confederation of Real Estate Developers’ Associations of India (Credai). He was

speaking at the inauguration of the Kakinada chapter of the Credai here on Sunday.

He said affordable housing for the low-income groups was the objective of the union Government and therefore service tax should be waived. He said labour cess of one per cent should also be levied only after the sale of apartments, and not at the stage of plan approval. He said the problem would be taken to the notice of the AP Government and efforts would be made to resolve the issue.

He said Credai, AP chapter, is making efforts to arrange skill development programme for 10,000 workers in the construction field in Andhra Pradesh.

The entire expense would be borne by the National Skill Development Corporation. He said Credai also has a consumer grievance cell and apartment buyers could take their problems to the cell and get them resolved. It would obviate the need for litigation.

waive serviCe tax on non-luxury houses’

Code of conduct

He urged builders to stick to the code of conduct formulated by Credai and deliver quality products to customers. “Our ultimate aim is to provide quality houses and apartments to our customers at affordable rates,” he said. He said the Andhra Pradesh Government had agreed in principle to do away with the need for obtaining permissions and to lay down construction norms which the builders should adhere to.

The Chief Minister had given a promise to that effect and he has constituted a committee for follow-up action. Sekhara Reddy thanked the AP Government for allotting exclusive sand reaches to Credai in the State. S. S. Balaram, the President of the Kakinada chapter, promised that local builders would adhere to the code of conduct laid down by the Credai and build quality houses and apartments for customers.

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advanCed teChnologiesin housing ConstruCtionBACKGROuND

Advanced technologies in housing construction are not used as frequently as the more standard construction technologies described in earlier chapters, which involve the use of masonry, timber, and concrete. However, as with other innovations, it is expected that over time these newer technologies will gain wider acceptance. For purposes of the World Housing Encyclopedia, advanced technologies include seismic isolation and passive-energy dissipation devices. As of this writing, the WHE database contains three reports describing the applications of advanced technologies: two of them describe base-isolation systems from China (WHE Report 9) and Kyrgyzstan (WHE Report 76), and the third report describes the use of a seismic protection system developed in the former Soviet union, called “disengaging reserve elements” (WHE Report 77, Russian Federation).

The first application of advanced technologies in housing construction

dates back to the 1970s. For example, the sliding-belt isolation scheme was developed in Russia around 1975, with its first application in Kyrgyzstan in 1982. The disengaging reserve elements (DRE) were developed in Russia in 1970 and first applied in 1972. The first code addressing this type of construction was issued in 1981. In China, the widespread use of base isolation for housing has only been employed since 1990, with the first code addressing this technology published in 2000.

SEISMIC ISOLATION (adapted from Mayes and Naeim 20011)

Seismic isolation is a relatively new concept in earthquake engineering, having been introduced in the early 1980s in the uSA and New Zealand, and as early as 1975 in the former Soviet union. Quite simply, the idea underlying the technology is to detach the building from the ground in such a way that the earthquake motions are not transmitted up through the building, or are at least greatly reduced. Seismic isolation is

most often installed at the base level of a building and is called base isolation. This new concept meets all the criteria for a classic modern technological innovation: the necessary imaginative advances in conceptual thinking, new materials available to the industry, and as can be seen in the WHE reports using isolators, simultaneous development of the ideas worldwide.

The principle of seismic isolation is to introduce flexibility at the base of a structure in the horizontal plane, while at the same time introducing damping elements to restrict the amplitude of the motion caused by the earthquake. The concept of seismic isolation became more feasible with the successful development of mechanical energy dissipators and elastomers with high damping properties. Seismic isolation can significantly reduce both floor accelerations and interstory drift and provide a viable economic solution to the difficult problem of reducing nonstructural earthquake damage, as illustrated in Figure 3.


There are three basic elements in any practical seismic isolation system. These are as follows:

• A flexible mounting so that the period of vibration of the total system is lengthened sufficiently to reduce the force response

• A damper or energy dissipator so that the relative deflections between building and ground can be controlled to a practical design level

• A means of providing rigidity under low (service) load levels, such as wind and minor earthquakes

Seismic isolation achieves a reduction in earthquake forces by lengthening the period of vibration in which the structure responds to the earthquake motions. The most significant benefits obtained from isolation are thus in structures for which the fundamental period of the building without isolation is short—less than one second. Therefore, seismic isolation is most applicable for low-rise and medium-rise buildings and becomes less effective for high-rise structures.

The WHE reports describe the applications of two different isolation systems:

• Rubber-based isolation system

• Sliding-belt isolation system

The rubber-based isolation system has been widely used in China (WHE Report 9). The system consists of laminated rubber bearings, with a diameter of 350 mm to 600 mm and a thickness of 160 mm to 200 mm. The isolators are reinforced by thin steel sheets. The isolators are installed on top of the basement walls or the columns, or at the plinth level in buildings without a basement. The most common application in China is for those buildings where the superstructure consists of common multistory, brick-masonry walls with reinforced concrete floors/roof. The cost of this system is u $145/m2. By the end of 2003, the system had been used in over 460 residential buildings in China. Sliding-belt isolation systems are installed at the base of the building between the foundation and the superstructure. The sliding belt consists of the following elements: (a) sliding supports, including the 2-mm-thick stainless steel plates attached to

the foundation and 4-mm Teflon (PTFE) plates attached to the superstructure, (b) reinforced rubber restraints for horizontal d i s p l a c e m e n t s (horizontal stop), and (c) restraints for vertical displacements (uplift)–vertical stops. Once the earthquake base shear force exceeds the level of the friction force developed in the sliding belt, the building (superstructure) starts to slide relative to the foundation. A typical large-panel building with plan dimensions 39.6 m x 10.8 m has 63 sliding supports and 70 horizontal and vertical restraints. The sliding-belt scheme was developed in CNIISK, Kucherenko (Moscow) around 1975. The first design application in Kyrgyzstan was made in 1982. To date, the system has been applied in over 30 buildings in Bishkek, Kyrgyzstan. The applications include 9-story, large, concrete panel buildings and 3-story brick masonry wall buildings.

In the uSA, New Zealand, Japan, and Italy, base-isolation technology has been used primarily to protect critical facilities, such as bridges, hospitals, city halls, courthouses, and heritage buildings. The most popular devices for seismic isolation of buildings in the uSA are lead-rubber bearings, high-damping rubber bearings, and the friction pendulum system (FPS). In Japan, as of 1999, over 300 residential buildings were protected with base-isolation devices2 (note that there were 700 base-isolated buildings in Japan at that time). Typical residential buildings are reinforced concrete frame or wall construction, more than 5 stories, perhaps containing hundreds of apartments. The majority of baseisolated residential buildings in Japan were built after the 1995 Kobe earthquake (M7.3), which caused over 6,000 deaths, mainly

as a result of vulnerable older wood housing3.

PASSIVE ENERGY DISSIPATION DEVICES

Passive energy dissipation systems represent an alternative to seismic isolation as a means of protecting building structures against the effects of damaging earthquakes. The basic function of passive energy dissipation devices in a building is to absorb or consume a portion of the earthquake input energy, thereby reducing energy dissipation demand on primary structural members and minimizing structural damage. The means by which the energy is dissipated is either through the yielding of mild steel, sliding friction, motion of a piston or a plate within a viscous fluid, motion of an orificed viscous fluid device, or viscoelastic action of polymeric materials. The most common types of passive devices used-to-date include viscous fluid dampers, friction dampers, metallic dampers, and tuned mass


against wind motions as well as against earthquakes.

Research and development of passive devices has a 30-year history. Most often, this technology has been used to retrofit existing public buildings that do not meet the seismic code requirements or were damaged by an earthquake. There are very few examples of the application of this technology to housing construction. In Canada, friction dampers were used in 1988 to retrofit a two-story wood house in Montreal. In theformer Soviet union, a unique passive seismic protection system called “disengaging reserve elements” (DRE) has been used to protect over 140 residential apartment buildings in the last 30 years, and it is the only application of passive-energy dissipation devices currently included in the WHE.

The DRE system was developed around 1970 in the former Soviet union (WHE report 77, Russian Federation). A building with the DRE system must be made with a flexible reinforced concrete frame on the ground floor while the upper stories may be made with any of the more rigid systems: typically, large precast

panel construction or brick masonry wall construction. The elements are constructed within the bays of the reinforced concrete frame on the ground floor. They consist of a “rigid structure,” generally RC wall panels, connected to the adjacent RC frame members by means of disengaging restraints. The DRE do not carry any gravity load and are only installed to act as a part of the lateral load-carrying system. The disengaging restraints, which connect the DRE to the RC frame, are sacrificial reserve elements (fuses) that are designed so that they will be the first structural members damaged in a large earthquake. Typical restraints are made of steel plates joined together by means of rivets or steel bolts, steel bars, concrete prisms or cubes. Initially (at the lower ground motion levels), the DRE and RC frame system (at the ground floor level) work together as a rigid structure;

at that stage, disengaging elements transfer lateral loads to the DRE (RC panels). However, once the lateral load exceeds the prescribed level (depending on the site seismicity and other factors), the disengaging elements snap and disconnect from the DRE. At that stage, due to the suddenly increased flexibility, a building changes its vibration period to a higher value of about 0.8–1.0 sec. As a result, resonance effects are avoided and seismic demand is reduced. After an earthquake, disengaging restraints need to be replaced. However, the cost is not high and the replacement is not complex.

This system was developed by Professor J. Eisenberg. The first building using the DRE system was constructed in 1972 in Sevastopol, ukraine (the former Soviet union). The system has been widely used in earthquake-prone areas of Russia and Kyrgyzstan. In Russia, about 140 buildings are protected with this system, primarily in North Baykal City and Siberia. There are several dozens of buildings with this system in Kyrgyzstan, Kazakhstan, Tajikistan, and Georgia. Most of the buildings are residential and

currently occupied.

EARTHQuAKE PERFORMANCE

Typically, all the buildings built with these new technologies have performed or are expected to perform well in major earthquakes. In fact, unlike some of the other construction technologies described in the WHE, this technology is used to improve a building’s performance in an earthquake. In China, where the use of base isolation for rigid masonry buildings is becoming more widespread, these buildings have been subjected to numerous strong earthquakes and have all performed well. No damage to this building type has been observed in any of these earthquakes: 1994 Taiwan Straits (M 7.3); 1995 Yunan Province (M 6.5); 1996 Yunan Province (M 7.0), and the 2000 Xinjian Autonomous Region (M 6.2).

RETROFIT

Again, unlike some of the other construction technologies described in the WHE, buildings built with these advanced technologies do not need to be strengthened to improve their performance in earthquakes. Rather, these technologies can be used to strengthen buildings. Some structures are inherently more suitable for retrofit using seismic isolation than others; for example, bridge superstructures lend themselves to the replacement of steel bearings with elastomeric ones. Buildings are typically more difficult to retrofit than bridges. A Marina apartment building in San Francisco, California, is one of the rare applications of base-isolation technology for seismic retrofit5. This four-story, wood frame building was severely damaged during the 1989 Loma Prieta earthquake. In 1990, thirty-one Friction Pendulum (FPS) bearings were installed at the base of the new garage-level steel columns. FPS bearings “isolate” the structure from the most damaging earthquake motions by using the characteristics of a pendulum to lengthen the structure’s natural period. The total retrofit cost was less than the cost to structurally upgrade the building to the seismic requirements of the then current uBC code. Interestingly, this building is considered to be the first base-isolated building in Northern California.


credai - confederation of real estate developer's

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