September_1971 — Page 27

A research report on:

Building on slopes

In terms of construction, it is more practical to build cities in the valleys and plains. Moving heavy construction equipment up the slopes, installing utilities, and building roads on the slope are usually prohibitively costly ventures. The constant threat of slides due to poor soil conditions magnifies the problems of hillside construction and living.

Yet many of the world's most populous urban areas must adapt to hillside building sites, Hong Kong, Los Angeles, Rio de Janerio, Honolulu, Pittsburgh, and Caracas are all contained within steep slope areas; their only alternative is to build up on the slopes.

This report presents a means of dealing rationally with the problems of developing steep slope areas. The concept is directed towards an individual building which is tailored to the demands of the slope sites. The proposed design consists of the following elements:

A small part of the building is required to be developed on relatively flat land at the base of the slope. The foundation on the flat area consists of standard element pilings, both vertical and slanted as needed for the load re- quirements.

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A shallow foundation strip is laid on the slope as a base for the building structure resting on the slope.

The floors of the building are then sequentially installed up from the foundation at the base of the slope. When completed, the building approximately assumes the shape of a triangle, with the vertical front and the top forming the two legs of the triangle, and the side resting on the slope, the hypotenuse.

The advantage of such a structure is that the heaviest gravitational load is on a standard foundation system at the base of the slope and not on the relatively weaker slope area. The loads which the weaker slope area cannot accommodate are transferred to the base pilings by the foundation strip. The slanted pilings at the base accept the sliding forces and eliminate the probability of building slippage due to poor geological conditions. Economically, the building may be erected using standard construction techniques which avoid the costly and dangerous use of heavy construction equipment on the slope. As each floor is installed, the construction for the next floor takes place on top of the previously finished floor. Access to the building is through the use of standard mechanical systems.

The proposed building shape in its specific locations is ideal for a large variety of applications: housing, education, commercial and sea and mountain resorts.

TRADITIONALLY, the security of the hill top was chosen for its inacces- sibility. Many fortified structures were positioned on these peaks, both for the self security and the commanding view. Gradually, cities sprang up around the peaks, forcing construction to take place on the slope areas. Also, cities were likewise developed along coast lines to exploit the sea, necessita- ting the development of building on slope areas. Practical methods were employed in construction and ter- racing, utilising rock if possible.

The same techniques used by the early peoples are still duplicated to- day. The houses are positioned on rock foundation material that has been levelled from the slope wall. Mostly the building was of relatively light material and low loading construction techniques. If the houses did not suc- ceed in maintaining themselves on the slopes, they were built again using dif- ferent methods and different loca- tions till a match of technique and lo- cation allowed success. Thus, clusters

The research was undertaken at the Mas- sachusetts Institute of Technology, School of Architecture and Planning, Department of Architecture, in 1969. Participants in- cluded Professor Waclaw P. Zalewski and research assistants Mr M. Robert Kirby and Mr Reinhard K. Goethert.

Far East BUILDER, September 1971

tended to be established which have continued through the ages. Italian hill towns are a good example of the early techniques and protective aspects.

When land conditions were too steep, little building was attempted. In extremely poor soil conditons, little construction was possible. Develop- ment was easier on the plateaus or at the base of a mountain. The problem of changing levels in a practical man- ner is still unsolved. The Greek city in the drawing shows the construction of the city on the base of the slope and on the plateau; no construction was possible on the slope.

Today the contemporary methods employed still rely upon time honour- ed approaches, terracing and low load- ing construction procedures and struc- ture. Access to the site on slopes is still very expensive and a complicated pro- cess. In the past, roads were tediously cut out of the slopes with the ever pre- sent danger of erosion. This method of cutting into a slope in order to build a road is still done today, and also in the positioning of buildings and terracing. Now the use of the bulldozer can simplify the job where soil conditions are favourable. Where soil conditions are not so favourable, laborious cut ting into the slope is still undertaken. Some exotic building systems have

Old Greek town: No building on the slope

been proposed to handle the slope building problem. In Pittsburgh, a system of huge cantilevers and inclined mechanical circulation systems is pro- posed. All of the techniques are ex- tremely costly in terms of expense and difficulty of construction.

Problems

Probably the most severe con- straint on a slope is the inability of easy access pedestrian or vehicular. Present solutions of terraced roads,

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