Download and Preview : Devil Physics The Baddest Class On Campus IB Physics
Report CopyRight/DMCA Form For : Devil Physics The Baddest Class On Campus IB Physics
DEVIL PHYSICSTHE BADDEST CLASS ONIB PHYSICSPRE IB PHYSICS LSN 9 7 FRACTURE.LSN 9 8 SPANNING AARCHES AND DOMES Objectives Know the meaning of the termsultimate tensile strength ultimate.compressive strength and ultimateshear strength Apply given safety factors todetermine a not to exceed force perunit area . Explain how reinforced concreteand prestressed concrete are made Objectives For a given situation determine the unitarea required to support a maximum.allowable force with a given safety factor Describe how a post and lintel opening is Explain why an arched opening cansupport more weight than a post and lintel opening . Describe the relationship between anarch and a dome Ultimate Strength F A Ultimate strength is the maximumforce per cross sectional area that a.material can withstand before Table 9 2 Maximum Tensile Strength Maximum Compressive Strength Maximum Shear Strength. Different values for each type of Ultimate Strength F A Ultimate strength is F A L L0 F E L. A MAX L0 Ultimate Strength F A Ultimate strength is F A F E L. A MAX L0 stress MAX E strain Safety Factor If the ultimate strength is the.maximum a material can withstand you want to design a structure sothat the maximum anticipated loadis something less than the maximum We do this by applying a safety. Safety Factor We do this bydividing the ultimate F UltStr strength by the A MAX S F .safety factor This allows us to UltStrfind maximum forceFMAX A for a given cross .sectional area F S F Or minimum area UltStr for a given force Making Concrete Stronger Concrete is extremely strong in.compression but weak in tension Reinforced concrete embeddingiron rods to increase tensile andshear strength Pre stressed concrete applying a.tensile stress to iron rods or meshwhen the concrete is poured aroundthem giving the concrete a pre settensile load which allows them to Arches and Domes. In a post and lintel entryway all ofthe structure s weight above theentryway is supported by sheerstress in the lintel and compressivestress in the posts . Arches and Domes Because an arch isat an angle to theweight the normalcounteracting the.weight will have x FNand y components Arches and Domes The x componentof the normal force.is transmitted tothe walls next tothe archway The shear stress in FNboth x and y .directions aredistributed over awider cross sectional area Arches and Domes. Therefore an archcan support agreat deal moreweight than a postand lintel made of.the same materialand same cross sectional area Arches and Domes Also the greater the height to width ratio the.greater the supporting capacity because moreweight is transferred to the walls and greatercross sectional are to handle the shear stress Arches and Domes A dome is an arch that is rotated.360 and provides the same supportproperties as an arch Do the reading activity to gain betterunderstanding and to appreciate thehistorical and architectural.significance of arches and domes LET S DO SOMEHOMEWORK PROBLEMS Objectives Know the meaning of the terms.ultimate tensile strength ultimatecompressive strength and ultimateshear strength Apply given safety factors todetermine a not to exceed force per.unit area Explain how reinforced concreteand prestressed concrete are made Objectives For a given situation determine the unit.area required to support a maximumallowable force with a given safety factor Describe how a post and lintel opening is Explain why an arched opening cansupport more weight than a post and .lintel opening Describe the relationship between anarch and a dome QUESTIONS 55 62 63 is for.brilliant students only reinforced concrete. and . prestressed. concrete. are made. Objectives. For a given situation, determine the unit area required to support a maximum allowable force with a given safety factor. Describe how a post-and-lintel opening is made. Explain why an arched opening can support more weight than a post-and-lintel opening.