Water supply systems’ vulnerability towards physical, chemical, biological, and cyber threats was recognized and was under study long before September 11, 2001. But greater attention toward security measures for water supply systems was focused after the incidents of September 11, 2001. In response to those events, several acts have been passed by the United States Congress, and numerous vulnerability assessment tools and methodologies for water systems have been developed. Although water supply systems are vulnerable to many forms of terrorist acts, most of the vulnerability analysis studies on these systems have been for chemical and biological threats. Because of the interdependency of water supply infrastructure and emergency fire response, any substantial damage in a water system would be a significant threat towards the community. In this study, attention is focused toward physical threats on water supply systems during a fire flow condition, and a methodology is developed to determine the vulnerable components of a water supply system during a fire event. The methodology utilizes dynamic programming optimization procedure to determine maximized disruption of fire flows as a function of number of attacks and/or failures in the water distribution system. Disruption is quantified at specific fire hydrants in two schemes using normalized values of (1) available flow and (2) available pressure and distance to the nearest operational fire hydrant. It is found that the pressure-based quantity is inferior to the flow-based one. However, using the flow-based disruption metric, clear functions of disruption versus failure number can be determined that exhibit discernable properties of robustness and resiliency – and the sequential failures in each. This methodology is applied to the water supply system of Micropolis, a virtual city developed by Brumbelow et al. (2005), and vulnerability analysis is performed with fire at several possible locations. On the basis of the results, three mitigation strategies are proposed to harden specific sets of water mains and more simulations are performed on the hardened water supply system to assess its changed vulnerability. The results from the simulations of the mitigation strategies show that the recommendations on specific mitigation measures reduce the serious consequences from such threats.

This study analyses the applicability of cross correlating the signal between two thermocouples to obtain simultaneous measurement of velocity, integral turbulent length scales, and temperature in fire induced turbulent flows. This sensor is based on the classical Taylor's hypothesis which states that turbulent structures should retain their shape and identity over a small period of time. If sampling rate is fast enough such that the signal from two thermocouples is sampled within this time duration, the turbulent eddy can be used as a tracer to measure flow velocity and fluctuation. Experiments performed in two laboratory scale devices: a heated turbulent jet and a variable diameter natural gas burner show that sampling rate, sampling time, and angular orientation with respect to the bulk flow are the most sensitive parameters in velocity measurements. Flows with Reynolds numbers between 300 (u=0.1m/s) and 6000 (u=2.0 m/s) were tested.

Den brandskyddsmetod av bjälklagsbalkar som används mest idag är brandskyddsfärg och brandskyddsskivor. Dessa metoder kräver ett extra arbetsmoment efter att balken är monterad. Genom att fylla balken med betong samtidigt som hålbjälklagskarvarna fylls och på så sätt integrera brandskyddet i balken kan ett extra arbetsmoment undvikas. Byggnadstekniska Byrån har märkt ett intresse från beställare att i ett tidigt skede få in brandskyddet i projekteringen.  Målet är att undersöka om betong, ingjuten i en HSQ-balk kan få balken att uppfylla de brandskyddskrav som idag ställs enligt Boverkets byggregler. Målet är även att ta reda på om det är kostnadseffektivt jämfört med brandskyddsfärg.  Referensobjektet som används är en skola på tre våningar och balken som undersöks är den som tar upp de största lasterna i projektet. Balken ska enligt Boverkets byggregler klara av en standardbrand i 60 min. Temperaturanalysen av balktvärsnitten har gjorts i Ansys Aim 18.2 och dimensioneringsmetoder av balken sker enligt Eurokoder.  Balken som idag finns på plats skulle inte i oskyddat tillstånd klara av en standardbrand i 60min. De utförda beräkningarna visar att balken i samverkan med betong och armering i tvärsnittet skulle klara momenten och tvärkrafterna i referensobjektet. Fenomen så som spjälkning av betong, dess inverkan på betongens hållfasthet samt armeringens vidhäftning har inte kunnat tas i beaktning. Därför rekommenderas att balkens underfläns dimensioneras upp från 20mm till 30mm och enbart betraktar den ingjutna betongen som kylande medium.