Monday, July 11, 2011

High Rise Buildings

High Rise BuildingThe high-rise building is generally considered as one that is taller than the maximum height which people are willing to walk up; it thus requires mechanical vertical transportation. This includes a rather limited range of building uses, primarily residential apartments, hotels, and office buildings, though occasionally including retail and educational facilities.

High-rise building is defined as a building 35 meters or greater in height, which is divided at regular intervals into occupiable levels. To be considered a high-rise building a structure must be based on solid ground, and fabricated along its full height through deliberate processes (as opposed to naturally-occurring formations).

A high-rise building is distinguished from other tall man-made structures by the following guidelines:

1. It must be divided into multiple levels of at least 2 meters height;

2. If it has fewer than 12 such internal levels, then the highest undivided portion must not exceed 50% of the total height;

3. Indistinct divisions of levels such as stairways shall not be considered floors for purposes of eligibility in this definition.

Any method of structural support, which is consistent with this definition, is allowable, whether masonry, concrete, or metal frame. In the few cases where such a building is not structurally self-supporting (e.g. resting on a slope or braced against a cliff), it may still be considered a high-rise building but is not eligible for any height records unless the record stipulates inclusions of this type.

Minimum Height

The cutoff between high-rise and low-rise buildings is 35 meters. This height was chosen based on an original 12-floor cutoff, used for the following reasons:

1. Twelve floors is normally the minimum height needed to achieve the physical presence which earns the name high-rise.

2. The twelve-floor limit represents a compromise between ambition and manageability for a worldwide database.

A building of fewer floors may only be included as a high-rise when its exact height is known. In most cases, a city is considered to have a satisfactory listing of high-rise buildings when all twelve-floor buildings are counted.

Single vs. Multiple Building

In most cases there is no trouble deciding what constitutes a separate building. Only when they are linked in unusual ways is there a logical difficulty. The following rules have been adopted to set a uniform standard:

1. Any two towers, which are separated for at least 2/3 of each towers height, are considered separate buildings unless the connection(s) form an unmistakable architectural unity, such as an arch-shaped building. Sky bridges are generally not sufficient to unify two separate towers.

2. Any structures which adjoin each other for more than 1/3 of any of their heights should be considered 1 building unless:

- They were built as separate structures and neither one can be considered an addition to the other; this means that the interiors are not integrated at any level, including the ground floor or basement; or
- The structures are separated at ground level and connected for most of their heights but are normally considered separate buildings; or
- An addition to a building forms a significant architectural disjunction.

3. An addition on top of an existing building is never counted as a separate building from the one underneath unless it overhangs the lower building from another base.

High - rise market

Undeniably the high-rise building is also seen as a wealth-generating mechanism working in an urban economy. High-rise buildings are constructed largely because they can create a lot of real estate out of a fairly small piece of land. Because of the availability of global technology and the growing demand for real estate, skyscrapers are seen as the most fitting solution to any city that is spatially challenged and can`t comfortably house its inhabitants. And hence, may be it is rightly said that `When you compare the population in our cities with the amount of land we have, the only way to provide better living conditions is by building higher`.

About Skyscrapers

The geographer Yi-Fu Tuan called it `the vertical aspiration` - the human desire to defy gravity. There has always been a relentless quest for height in architecture through the ages. The pyramids and the spiraling towers are instances of man striving to create something awe-inspiring in the past. `The two main reasons people go for skyscrapers are either sheer necessity or to depict power and glory. And both are justifiable`, says architect Hafiz Contractor. Skyscrapers are always associated with power and grandeur, and they may well become indispensable in future Indian cities.

The word `skyscraper` was coined in the late 19th Century, reflecting public amazement at the tall buildings being built in New York City. The structural definition of the word `skyscraper` was created later by architectural historians, based on engineering developments of the 1880`s, which had enabled construction of tall multistory buildings. This definition was based on the steel skeleton, as opposed to constructions of load-bearing masonry, which passed their practical limit in 1891.

Friday, April 15, 2011

Panel tightens norms for high-rise buildings

Learning lessons from the Adarsh housing scam, the state high rise committee has framed new guidelines that make it mandatory for builders to submit a final plan before seeking approval. The new rules will stop developers from changing their plans once the committee clears a proposal.

In its guidelines formalised a few weeks ago, the committee has specified that builders will have to submit their applications based on the available FSI. In the case of Adarsh, former civic chief Jairaj Phatak approved additional FSI but he did not send back the revised plan to the high rise committee. City builders have always exploited loopholes in the rules by submitting plans for a certain number of floors and seeking permission to add more floors by way of additional FSI or TDR (transfer of development rights) once they get approval.

The committee has recommended that the developer must submit a detailed layout plan, including details of buildings around a 1.3 km radius of the proposed project. Details would include mentioning the main access road, its width, the number of proposed high rises in the vicinity, buildings of archaeological importance, heritage sites, schools, places of worship, forests and national parks and the distance between each structure.

Developers will have to keep an appropriate space for pedestrians, fire brigade, ambulance, and riot vehicles.
Developers might also have to abandon glass facades, a committee member said. Builders go for glass without understanding the city’s climate, he said. “If a glass facade breaks, it can cause damage on the streets because the city’s population density is very high,” the committee said in its report.
According to the new guidelines, the developer will also have to submit details of water supply and distribution and how it will be used in flats, garden, and sewers.

The committee wants to maintain the city’s aesthetic view. New high rises should not come in the way of landmarks and historic buildings, the member said.

Also, the facade cannot be featureless and bland; the structure has to match those in surrounding areas. The minimum distance between two high rises will have to be 20 metres.

Developers will have to carry out several surveys, including environmental impact, traffic, open space, soil profile study, availability of amenities, energy, water use, and wind analysis.

“The new high rise guidelines will help improve the quality of life and rejuvenate the environment condition,” the committee said in its report. Retired high court judge and high rise committee chairman SS Parkar said that the final guidelines would be applicable to all proposed high rise buildings (above 70 metres).