feasible in situations where access from both the top and the bottom of the slope is practicable. One crane would be at the base plane and the other at the top. Some overlapping of the systems would be required in this approach.
(4) Another approach would be to use a base plane hoist for vertical movement and manual moving systems for horizontal capacity. Lift trucks, construction carts or manual cranes might be used. Lightweight, small cle- ments are prerequisites in construction with this system.
(5) Another approach is the use in multi-core buildings. A slip-formed core would allow a climbing crane to build with section of the building within its reach. Further vertical cores up the slope would also contain climb- ing cranes and provide hoist capacity in their respective areas. From the tops of the fixed cores the cranes can as- semble a simple frame with no lateral stability needs for the cores brace the entire structure.
(6) A portable derrick crane may be used for both vertical and horizontal hoisting if sequenced to grow with the structure.
Basic to the construction system is the principle of a main mechanical system for vertical movement of rela- tively light structural elements and equipment. In general, standard con- struction procedures may be applied in the use of this concept.
Construction is by moving from the bottom platform up, constructing a level at a time, with each preceding level providing the base for construc- tion of the next level. In this manner, there is no need for access of heavy equipment on the sloped surface which could result in damage to the sensitive sloped surface and also in- crease the cost of construction.
The apparent appropriate construc- tion system for the method proposed is:
(1) The use of light, prefabricated elements, steel frames, light concrete panels, etc.
(2) The use of in-situ concrete structures; inherent is the use of mova- ble forms and pumped concrete.
(3) The use of composite systems with both of the methods 1 and 2.
Vertical circulation cores may easi- ly be built using slip-forming techni- ques on which a hoist or construction elevator can be mounted to provide the vertical muscle necessary during
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construction.
Steel systems: Perhaps the most ap- propriate method of development of the approach is through the use of steel structural systems. Steel members are relatively lightweight, easily handl- ed, and the assembly process is quick and simple.
Whatever framing system is pro- posed, its steel members are per- haps uniquely suited to the vertical lift-horizontal placement mode of con- struction procedure inherently charac- teristic to the presented approach.
Precast components: With the cen- tral core slip-formed, the remainder of the building may be constructed using all precast elements. Light, small piece elements can be easily transported horizontally by lifts, portal cranes or manually aided devices.
Flying forms: These movable forms provide a means of eliminating move- ment of large elements or hoist machinery in construction. Developed for in-situ construction, the movable formwork allows a large time reduc- tion between pours. Vertical move- ment of the forms are by hoist; hori- zontal movement can be accomplished with manual labour.
Staggered beam walls: In many cases the walls themselves can be so. structured as to act as beams with a depth of the floor to ceiling height. In one case, the beam walls are cantilever- ed from a central support core. This core would be cast first.
The beam walls may be so arranged as to allow spaces twice the normal spanning distance. This is achieved by staggered beam walls on the alternate levels.
By using this method, much larger spaces may be planned in buildings (twice the normal spans) and a more efficient internal span system is achie- ved.
Skip truss: In this approach the beam walls are trusses. Again the trus- ses are supported from the central core. In this case, however, the beams are designed to take the load of two floors, which is possible due to the depth of the beam. This allows posi- tioning of the beam walls only on alternate floors, with the result of gaining a floor without internal sup-
ports other than the central core.
Regular spacing is maintained in the beam wall. The staggered beam wall system allows twice the spacing between beam walls but does not gain the support free interior space.
Infill system: The structure con- sists of a major permanent frame at intervals of five floors. Most probably developed in concrete, the main floor elements become the supporting struc- ture for five floors of semi-permanent light frame construction.
A five floor limitation was chosen because of the limiting capability of light frame construction. The infill structure would be steel, possibly even wood, or indigenous material.
The advantage of this system is the inherent capacity to adjust to change; both in obsolescence and in function. Spaces of two, three or even five floors in height may be later planned in the structure without affecting the sup- porting structure or necessitating cost- ly alterations.
Suspended structure: A means of eliminating the use of hoisting systems entirely is by utilising a structure system suspended from a major over- head beam frame. The central circula- tion and utility core is slip-formed while simultaneously the compression element along the slope is cast. An overhead beam system connecting the core and the compression member pro- vides the hoist mechanism for lifting precast floor elements (or supports the formwork for in-situ construction).
(A) The central circulation and utility core and the compression spine on the slope are slip-formed.
(B) A beam framework is erected on the slip-formed cores.
(C) The framework provides the hoisting system as well as the support for the elements of the building.
A variation of this method is by using the cable system to support the formwork for poured in place floors, either developing the floors from the top down or the bottom up. The forms themselves could later be inter- nalised as part of the building; perhaps as a mechanical room, storage space, etc.
Planning considerations
Two basic networks of utility systems may be developed in the building.
(1) Use of the circulation core as the main element of distribution lines. Secondary feed lines would run hori- zontally from the core.
(2) The prime distribution lines would run along the spine of the build- ing. Feed would be up from the spine to the secondary lines.
A composite of the two positions
Far East BUILDER, September 1971