The skyline of many 'world cities' are defined and punctuated by tall buildings. The drivers for such dominant skylines range from land scarcity and social needs; high real estate values; commercial opportunity and corporate demand, through to metropolitan signposting. This fascination with tall buildings started with the patrician families who created the 11th Century skyline of San Gimignano by building seventy tower-houses (some up to 50m tall) as symbols of their wealth and power. This was most famously followed in the late 19th Century with the Manhattan skyline, then Dubai building the world's highest building, then China building some eighty tall buildings completed in the last 5 years, then UK building Europe's highest tower, the Shard and finally back to Dubai, planning a kilometre tall tower, potentially realising Ludwig Mies van der Rohe's 'Impossible Dream' of the 1920's and Frank Lloyd Wright's 1956 'Mile High Illinois'. This ambition to build higher and higher continues to challenge the Architects, Engineers and Builders of tall buildings and is expected to continue into the future. The tall building format is clearly here to stay.

Until recent developments, labor productivity had been analyzed manually requiring time-consuming work and the possibility of human error. Past research has shown the multitude of benefits obtained from implementing radio frequency identification technology within various construction sites including asset tracking, inventory management, and on-site security upgrades. Additional construction improvements can be identified in terms of productivity analysis of work crews, material transport, and the overall approach to a project to determine whether the construction process is operating at maximum efficiency or can be adjusted to improve its effectiveness. This paper presents the results of implementing radio-frequency identification technology and provides a study of labor productivity analysis for a window replacement project on a high-rise construction site. This extensive study tracks the efficiency of a buck hoist worker and material lift system for transportation and illustrates the applicability of the technology despite the presence of numerous signal impeding obstacles located throughout the site. These issues are resolved with an effective automated location and time tracking system that work in both an indoor and outdoor environment simultaneously with a data recording software and database. The in-house development of the database allows for timely information retrieval of various items of interest in this study and requires less The experimental results show that RFID technology has the capacity to work and produce useful data for labor productivity purposes in an ever-changing construction environment. The research further recognizes relevant information regarding system optimization and worker feedback for future use.

Modern construction practices require proper knowledge to predict concrete pumping pressure, especially in high-volume and high-rise applications. Despite the progress made over the last decades, the spread of concrete pumping to high-rise construction has been hampered by the lack of standardized operating procedures and performance criteria. By and large, the guidelines available today focus predominantly on pumping Conventional Vibrated Concrete (CVC), while ambiguity still surrounds pumping Self-Consolidating Concrete (SCC) and other types of Highly-Workable Concrete (HWC). This PhD dissertation focuses on the fundamental principles relevant to the flow of high-strength SCC in pumping pipes, and it aims to develop methods to predict and reduce the required pumping pressure. The flow pattern of SCC in pipes is analytically investigated, providing a numerical approach to predict the pumping pressure based on the properties of both concrete and the lubrication layer, the pipe diameter, and the flow rate. The analytical results are further validated through full-scale pumping tests executed at the laboratory of the Université de Sherbrooke. Through this phase 26 optimal concrete mixtures were pumped in a 30-m pumping circuit to investigate the interactions between the concrete properties and pressure loss. The same tests are also employed to empirically correlate pressure loss with rheological and tribological properties of concrete at different flow rates. The resulting correlations furnish instrumental models capable of computing pressure loss for a wide range of concrete properties. In another application, the experimental results are analyzed to identify the influence of pumping on concrete properties with time. Full-scale pumping results are statistically analyzed in order to establish a quantitative description of the most influential parameters governing the concrete flow in pipes. As a result, concrete pipe flow is statically modeled, allowing the computation of pressure loss at different flow rates based on the the rheological and tribological properties of the concrete and the pipe diameter. Another statistical model is derived to calculate the pressure loss as a function of the V-funnel flow time, granting the advantage of predicting the pressure loss on job sites without the need for complex rheological and tribological measurements. In light of the research findings of the previous phases, a new simple test method called the pipe flow test (PFT) is developed in the context of this research, specifically for predicting pipe flow pressure loss. With preceding research phases as insights, the final stage of this project is directed toward mix design optimization faced with the challenge of reducing the pumping pressure and meeting the strength requirements of high-strength SCC. Ultimately, the research findings emanating from this investigation provide practical guidelines and conclusive models to predict and reduce pumping pressure for a wide scope of concrete mixtures and pipe diameters.