█ _ كاتب غير معروف 2010 حصريا كتاب Building Research Establishment Geotechnics for building professionals عن BRE Bookshop 2024 professionals: نبذه الكتاب: FOREWORD Having been Head of the Division at Building Research Station from 1972 to 1980, it is a particular pleasure for me be invited write this foreword Written nonspecialist, book distillation large reservoir of expertise, experience and guidance on foundations low rise buildings which has accumulated over many years This experience based research into actual behaviour of buildings founded wide range difficult ground conditions, studies effectiveness various ground treatment methods detailed examinations causes and severity damage in hundreds buildings For many, indeed most, structural engineers, geotechnics something black art The ground is mysterious: every trench, hole excavation opened up journey an uncharted underworld When problems with occur, rumours abound – underground streams, old wells, hidden cavities, previous uses site so On one occasion, I visited a foundation Salisbury, bottom had turned soft slurry owing to upward seepage water, was told by engineer that whole Salisbury floating on liquid chalk! Why comes across as mysterious inaccessible subject? For most building materials, such steel, cement, concrete brickwork, stiffness strength can specified and remain reasonably fixed dependable soils, however, depends on stress acting them water pressures within them, these change significantly during after construction In cases, professional cannot specify the founding material but work what nature provided; seldom straightforward To understand methodology geotechnical engineer, helpful compare the approach adopted structural or working ancient A detailed inspection essential discover materials were used how was constructed Special attention given detecting signs weakness defects since can dominate Historical records reveal history give important clues as building’s overall response This demonstrates works exactly same way First, discover what there: ground profile groundwater conditions they vary rise buildings, highly sophisticated testing rarely required; usually necessary know only soil types are (fine coarse material) dense (density indicator of strength) Particular emphasis must placed identifying site, potential hazards Much learned local such as aerial photographs old maps Skimping investigation lead very costly timeconsuming corrective measures, just So Chapter 5 Ground assessment fundamental ‘must read’ Biology Books مجاناً PDF اونلاين Biologically Biology natural science concerned study life, its forms function, organisms interact each other surrounding environment word biology Greek made two words: bio (βίος) meaning life And loggia ( λογία) means Biology: similarity vegetation animal cover edges African American states, existence fossil Branches biology Biology thousands modern began nineteenth century This multiple branches Among are: Anatomy Botany Biochemia Biogeography Biofisia Cytology cell science Ecology environmental science Development Embryology embryology Genetics genetics Histology histology Anthropology anthropology Microbiology bacteriology Molecular Biology Physiology functions organs Taxonemia taxonomy Virology virology Zoology zoology