WORKPLACE SAFETY AND HEALTH PRACTICES AWARD 2011 Silent Black Balls (SB2)
COMPANY INTRODUCTION In Singapore, we act as the main contractor in construction projects for both private and public sectors Over 50 years of experience in Singapore's construction industry Listed as Tiong Seng Holdings Limited in 2010 Holds the highest A1 grading from Singapore s Building & Construction Authority ( BCA ) Applies to both general building & civil engineering projects Qualifies us to undertake public sector construction projects with unlimited contract value Holds BCA s General Builder Class 1 with specialist builder license for Piling works, Ground Support & Stabilization, Structural Steel & Precast Concrete Works A leader in technologies & capabilities Expertise in pre-casting Specialization in fabrication and supply of pre-cast mould and steelwork fabrication Usage of advanced formwork systems Usage of innovative systems such as BIM & Cobiax technologies Capellla, Singapore Marina Business Financial Centre MRT Stations & Tunnel @ Hillview & Cashew The Wharf Residence Resort World, Singapore
background Singapore Scarce in Land Land to house businesses and population People Professionals Constr. Materials Coarse and Fine Aggregate Land for transportation Skilled Workforce Cement General Workforce Steel Taller buildings and deeper basements More infrastructures More Foreign professionals, skilled and unskilled workers Import construction and raw materials including water Increase Productivity Improve Competency Reduce Structure Dead Weight. Reduction in Structure Dead Load Reduction in Foundation Requirements Reduction in Constr. Materials incl. concrete & rebar Reduction in Inertia Force due to Seismic Excitation.
Basic idea TECHNOLOGY Cobiax system (www.cobiax.com) originated from Switzerland and was first brought into the Singapore market in 2009 and first execution in 2010. Taking inspiration from nature, the system helps optimize building structures thru the introduction of void formers. At the same time, optimizing the slab s thickness and quantity of building material to be handled Implementation Cobiax void formers, is designed and positioned in appropriate zones of flat slabs contribute to dead weight reduction without modifying flexural strength and load transfer to supports Properties and Benefits - Overview Fast Optimize foundation design reducing volume of piling works Reduce formwork placement time due to flat slabs with no beams Productive Simplify site logistics by reducing the volume of concrete and rebar used Reduce co-ordination issues by eliminating beams Green Reduce Carbon footprint of the building Reduce transport movement due to optimized building material usage Reduction in Structural Dead Load
Before After Risk/ Exposure Level before control Noise - 85 to 90 dba Vibration - Longer Exposure Traffic Control - For Concrete/Rebar Delivery Risk/ Exposure Level after control Noise Reduction - 70 to 75 dba Vibration Traffic Control - Shorter Exposure - Fewer Trips of Delivery Less fatigue for concreting worker Cost Cost Savings Time is reduced by 30%, Productivity increased by 30% Benefits Change of Bored Pile to Raft Foundation Reduction of concrete volume Reduction of rebar quantity Reduction of numbers of concrete mixer truck trips Improve floor construction cycle times Volume gain height reduction Promote recycling / reuse of plastics
Comprehensive Protection SB 2 provides comprehensive protection by: Replacing bored piles with raft foundation as the foundation system* Reducing concrete and rebar usage requirement o Eliminate approximately 200 nos. of bored piles Eliminate toppling hazards of heavy piling plants and machinery Eliminate Collapse of load tests Eliminate noise and vibration generated due to bored pile operation Original Site Condition o Reduce 890m3 of concrete volume which result in Lesser time and energy used for placing concrete Shorter worker s time exposure to noise and reduce deafness probability. Reduce 186,000 kg of CO2 produce Reduce 148 concrete truck trips Collapse of Load Test of other site o Reduce 300 tons of rebar which result in: Shorter time to place rebar Reduce 12 rebar trailer trips COBIAX VOID FORMERS o Promote recycling / reuse of plastics In general, workers who are likely to be exposed to hazards are provided with protection by reducing their prolonged exposure to concrete, noise and vibration. * Based upon case study of actual project, may vary depending on different project design requirements
Ease of Set-up and Use Design substitution control of SB 2 to the conventional work process is very simple and easy to implement. Robust to Handle It comes in cage modules with the void balls for easy mobility. It can easily be modified to suit site requirements and conditions Modular & Easy to Check Off-Site Fabrication Assembly of cobiax void formers into the positioning cages Delivery to site On-Site Installation Erection of slab formwork Fixing of bottom rebar Installation of SB2 modules and M&E piping concurrently Fixing of top rebar It is currently used in majority of Tiong Seng projects and have gained wide acceptance from workers who are first hand installing the SB 2, from consultants who are invited to witness site demonstrations and from subcontractors who are to carry out interfacing works.` Easy to Modify Casting as usual
Wide scope of application SB 2 our best practice, being a modular concept, is suitable for In-situ application Precast module Infrastructure works such as bridges & flyovers Use in combination with other building techniques such as post-tensioning and composite structures. Pre-Stressing Precast Innovation SB 2 is a best practice due to its light-flat-biaxial concept that reduce noise level during casting have many cost benefits mainly on concrete, reinforcement steel and the elimination of wire chair and piling due to its resource effectiveness through reduction in concrete, carbon dioxide emissions, optimize construction time, productivity and promote sustainability. Flyover Life Cycle Cost Since the SB 2 void formers are made of recycled plastic material, the company reaps the many benefits by using cost effective material which does not only remove the non-working dead load but also maintains the bi-axial strength of the structural slab.
Noise level due to piling & concreting Level of safety hazard during piling and testing Stress level to workers due to continuous large volume of casting Manpower deployment Quantity of material usage Energy consumption Eliminate noise and safety hazard due to piling Noise Level due to concreting Stress level to worker as concrete volume reduced Requirement of manpower deployment Usage of construction materials Consumption of energy