CONSTRUCTION OF A SPHERICAL SKELETON FRAME STRUCTURE BY PRECAST CONCRETE TECHNOLOGY

Abstract

The 100-year memorial Lady Master Chan’s Building is a master piece
symbolic building of Dhammakaya Temple at Khlong Luang, Pathum Thani,
Thailand. Water cooling system was selected to cool down temperature of a
5.40 meter deep mat footing with a volume of 10,944 m3 and 5,400 m3 of
transfer floor. The large volume mass concrete was not allowed by the owner
to use fly ash. Water cooling tower, normally used in building airconditioning
system, was adopted to be used for a closed circuit water cooling
system to eliminate the need of water reservoir, as the transfer floor was
located 27.50 meter above ground. The spherical shape of building is a unique
one. No building of this shape and size has been built with concrete Skeleton
before. The connected nodes of columns and beams, to form the triangle
shape of concrete skeleton were too narrow to accommodate all
reinforcement needed. Also the off-form exposed concrete surface without
rendering and painting are the important architectural requirements. Precast
Technology was implemented. The reinforced concrete elements were
converted to be composite section comprising of two 300 x 40 mm thick high
strength steel plate and DB40 rebar, encased by 750 ksc. high strength
concrete. High performance self-compacting concrete, with a slump flow of
600 mm, was needed to ensure that the precast concrete elements with
complicated shape and heavy reinforcement were perfectly casted. Nice and
smooth surfaces were achieved by using specially made steel formwork and
high frequency vibrator. The skeleton structure was categorized into precast
inclined column element, beam element and node element. The precast
elements were transported to the job site and lifted by 540 ton-meter tower
crane, to seat on a specially made temporary steel frame. The reinforcement
were connected and encased by high performance concrete. A nice looking
and high strength skeleton for the building were then achieved.