Issue link: http://digital.canadawide.com/i/1274063
Scenic Trails Condominium, Hamilton, ON. J U LY 2 0 2 0 | 9 Precast Concrete P H OTO G R A P H Y CO U RT E SY CO R E S L A B S T RU C T U R E S A s it might be expected in a com- petitive market, the choice of building materials must undergo rigorous scrutiny. However, the precast concrete industry is in a remarkable sit- uation in which architecture, engineering, and construction professionals, own- ers, and government officials are seeing the benefits of Accelerated Bridge Construction (ABC) and the total cost of ownership – which includes the pur- chase price of a particular product or system, plus operating costs over the asset's lifespan. Analyzing the total cost of ownership is a way of assessing the long-term value of a building product or system. Brian Hall, managing director of the Canadian Precast Prestressed Concrete Institute (CPCI), points out that "when all attributes and true expenses are added up, precast concrete products offer significant benefits in quality, speed, and short- and long-term cost savings over traditional building products." Hall elaborates, "Fabrication using strict qual- ity control techniques can be done while permits are approved and the site is prepped, so precast concrete components are being manufactured as the site prep and foundation work is done. This ensures sched- ule delays are minimized, site congestion and safety concerns are alleviated, fireproofing is eliminated, interim financing costs are lessened, and contractor risk is reduced." Given the benefits of precast, it follows that research to facilitate technological advances in the medium is ongoing. CPCI has continued its work with Queen's University to investigate the connec- tions of Ultra-High Performance Concrete (UHPC) Double Wythe Insulated Panels to building struc- tures, as well as to expand the knowledge on the performance of the UHPC panels when exposed to fire. CPCI is also working with the University of Manitoba to experimentally validate the benefits of transverse post-tensioning (TPT) of adjacent precast prestressed concrete box girders (the main objec- tive of this research program is to investigate the feasibility of eliminating transverse diaphragms by applying TPT in the top flange of the girders instead of mid-height; preliminary results show that top flange application is feasible, with very good strain and load distribution among the girders). Additionally, CPCI is participating in evaluating the capacity of reinforcing bar connections between hollow core slabs and supporting elements. The research into UHPC is justified, as ultra- high performance concrete is considered to be an emerging and significant trendsetter in the North American building sector. "Many compa- nies, including ours, are continuing to undertake research of UHPC in order to determine its com- pression and ductile strengths by using a variety of fibres, and in our case we are currently experiment- ing with PVA fibre for architectural applications," says Tim Smith, estimator and project manager for Surespan Structures Ltd. Although UHPC's high cost has so far limited its use in Canada, its potential is enormous: for exam- ple, UHPC has a minimum specified compressive strength of 17,000 pounds per square inch (120 Mpa) and can be formulated to provide compres- sive strengths in excess of 29,000 pounds per square inch (psi). "UHPC is ideal for overlays in retrofitting and also repair, such as wrapping concrete columns that have been damaged but are still structurally sound," says Smith. "UHPC is also ideal for expan- sion joints between precast panels on bridges, as the cementitious concrete material lasts far longer than the 25-year lifespan of traditional expansion joints." Surespan sees UHPC's biggest current potential being in the architectural realm, because the use of fine/compacted materials for UHPC's matrix also Precast concrete is being seen as the material of choice by ROBIN BRUNET On The Rise (CPCQA) CANADIAN PRECAST CONCRETE QUALITY ASSURANCE CERTIFICATION PROGRAM PROGRAM (CPCQA) CANADIAN PRECAST CONCRETE QUALITY ASSURANCE CERTIFICATION PROGRAM (CPCQA) CANADIAN PRECAST CONCRETE QUALITY ASSURANCE CERTIFICATION PROGRAM