tailieunhanh - Basic recommendations for earthquake protection_5

Tham khảo tài liệu 'basic recommendations for earthquake protection_5', khoa học tự nhiên, công nghệ môi trường phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | THE EARTHQUAKE EMERGENCY 113 Figure Methods of excavation to reach trapped victims in building rubble after Michael Markus redrawn with permission. lorries may be needed to take this rubble away to keep the site as clear as possible. Workers need gloves and may need to improvise masks against inhaling the dust on the site. For work to continue into the night illumination is needed preferably from construction floodlighting powered by generators but could be improvised from car headlamps if enough vehicles are available. For shoring large numbers of strong timber beams are required with hammers large nails and saws to fix in position. Scaffolding poles and extensible props are also useful. For larger pieces of structure crowbars and levers may be needed for a number of rescuers to be able to manoeuvre them out of position. Car jacks and lorry jacks may be used to prise blocks of a few tonnes by tens of centimetres. Specialist equipment has also been designed for jacking moderate-sized structured elements apart using air bags that are placed in position and then inflated. Spread over a large surface area these can move elements of many tonnes. For larger blocks more specialised and powerful equipment is needed. Construction and excavation machinery may be used to provide the power to move the more massive structural elements. If required these machines need to be used sparingly. Although powerful they are imprecise in their control and may cause unexpected movements of rubble that can kill the trapped victim. If possible it is preferable to use hand tools to break up larger elements and to reserve the heavy plant machines for dragging away material that is well away from known victims. Breaking up excavation requires cutters power tools or pneumatic drills. Cutting through steel reinforcing bars is the slowest part of concrete demolition requiring elaborate steel saws or flame cutters. For this reason some consideration should be given to where the cut is made .