Implementing a site waste management plan: a case study of a medium sized building contractor in Ireland

Construction and demolition waste management is becoming increasingly important on construction sites as landfill space in Ireland is rapidly depleting and waste management costs are rising. Due to these factors waste management plans are seen as a good response to minimising waste on site and this thesis aims to investigate how to implement such a plan on a practical case study as well as investigating the legislation regarding construction and demolition waste along with market availability for the reuse of the waste. Main contractor surveys were also carried out in order to gain a better understanding of current attitudes within the industry and these surveys are analysed in chapter five. A survey was also carried out among sub-contractors but this survey has not been used for this thesis as the study is on-going. The primary aim of this thesis is to examine the waste hierarchy opportunities that are available for construction and demolition waste in Ireland and to examine the effects of management strategies on construction and demolition waste reduction at the project level. A partnership was developed with Carey Developments Ltd in Co. Galway and an analysis of their waste management practices was undertaken. The primary case study will be the ‘Taylors Hill’ project in Co. Galway where work commenced in March, 2012. The secondary aim of the thesis is to develop specific waste minimisation strategies for the company and to develop a training tool kit for use on site.

Acoustic emission analysis of the effect of a 2D wedge shaped blade on the compact bone cutting process

Surgeons may use a number of cutting instruments such as osteotomes and chisels to cut bone during an operative procedure. The initial loading of cortical bone during the cutting process results in the formation of microcracks in the vicinity of the cutting zone with main crack propagation to failure occuring with continued loading. When a material cracks, energy is emitted in the form of Acoustic Emission (AE) signals that spread in all directions, therefore, AE transducers can be used to monitor the occurrence and development of microcracking and crack propagation in cortical bone. In this research, number of AE signals (hits) and related parameters including amplitude, duration and absolute energy (abs-energy) were recorded during the indentation cutting process by a wedge blade on cortical bone specimens. The cutting force was also measured to correlate between load-displacement curves and the output from the AE sensor. The results from experiments show AE signals increase substantially during the loading just prior to fracture between 90% and 100% of maximum fracture load. Furthermore, an amplitude threshold value of 64dB (with approximate abs-energy of 1500 aJ) was established to saparate AE signals associated with microcracking (41 – 64dB) from fracture related signals (65 – 98dB). The results also demonstrated that the complete fracture event which had the highest duration value can be distinguished from other growing macrocracks which did not lead to catastrophic fracture. It was observed that the main crack initiation may be detected by capturing a high amplitude signal at a mean load value of 87% of maximum load and unsteady crack propagation may occur just prior to final fracture event at a mean load value of 96% of maximum load. The author concludes that the AE method is useful in understanding the crack initiation and fracture during the indentation cutting process.