Title: CONSTRUCTION OF A SPHERICAL SKELETON FRAME STRUCTURE BY PRECAST CONCRETE TECHNOLOGY

Author(s): Si Krang Thong

Publication: TCA

Volume: 3

Issue: 1

Appears on pages(s): 9-21

Keywords: Mass Concrete, Water cooling system, Precast concrete, Spherical shape skeleton, High performance self-compacting concrete

DOI:

Date: 1/1/2015

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.