E14 - Applied Mechanics: Statics

e14 - applied mechanics: staticse14 - applied mechanics: staticswhy do things break? to reliably predict what’s going oninside a structure, we need to know the forces that act on it.it’s newton’s law that helps us to determine these forces.basically, this course is all about newton’s law, forceequilibrium, and its application to civil, mechanical,aerospace, and biological problems. we explore it forparticles first, then for two-dimensional, and finally forthree-dimensional systems. first we look at the structurefrom the outside, then from the inside. we learn how toidentify, formulate, and solve engineering problems. to do so,you should be familiar with and not afraid of maths, vectors,and basic physics.ellen kuhl, charbel eid, julianne gould, estevan mendoza, chris plochmon/wed/fri, 12:50-2:05pm, 370-370mon/wed/fri, 12:50-2:05pm, 370-370e14 - applied mechanics: staticse14 - applied mechanics: statics12textbook.russell c. hibbelerprentice hall, 12th editionengineering mechanicsstaticsstatics study packfor engineering mechanicstextbook. russell c hibbeler: statics.3 but our real bible is 4

e14 - applied mechanics: staticse14 - applied mechanics: staticsphilosophiae naturalis principia mathematica. isaac newton. [1687] but our real bible is 5e14 - applied mechanics: staticssyllabusnewton‘s laws6e14 - applied mechanics: statics7syllabus8

e14 - applied mechanics: staticse14 - applied mechanics: staticshomeworkexams20 % five homework assignments, 4% each80 % two midterms, one final, 30%, 25%, 25% eachfinal grade 90 A range 80 B range 70 C range 70 lowergrades, grades, grades 9homework. homework sets will be announced in class andassigned via coursework. homework will be graded forcompleteness, correctness, and clarity. assignments must becompleted in pencil on engineering computation paper.solutions must be legible and orderly, with complete andproperly labeled free body diagrams. answers must be clearlyboxed. the meaning of variables that you introduce must beclear. if the grader cannot read and follow your work, youwill not get credit. you have up to three late days to use overthe quarter. a late day is charged for any fraction of a daypast the due date. once you have used your allocation of latedays, further late submissions will be corrected, but willreceive a score of zero. the final homework may not besubmitted late.grades, grades, grades 10structural failuree14 - applied mechanics: staticsmidterm 1 wednesday, 04/20, in classmidterm 2 wednesday, 05/18, take homefinal exam to be announcedexams. your highest exam score will count for 30% of yourfinal grade and your other two exams will count for 25%each. the first midterm and the final are closed book/closednotes exams. you may bring one handwritten, letter sizedformula sheet to each exam but no photocopies or printouts.bring a calculator, but pre-programmed functions orprograms may not be used. the second midterm is a takehome exam. no internal or external communication ispermitted during the exam. all exams must be taken at thescheduled time.grades, grades, grades 11motivation12

structural failurereasons for structural failurewhen a structure fails, there is invariably an investigation tofind out why it failed. apart from the legal and professionalnecessity to determine the cause of failure, there is also theneed to learn from it lessons that would enable subsequentdesigners and builders to avoid the pitfalls of the failedstructure and develop safer alternatives. structural analysis conceptual errors drawings and specifications work planning and preparation combinationstechnological developments in recent decades have introducednew configurations, materials, and methods of design andconstruction that raise new and complex problems. failures arecaused by many unprecedented causes singly or incombination. paradoxially, in the pursuit of innovation, evenbasic principles of sound structural design and goodconstruction practice are often violated, leading to failure. ignorance, carelessness, negligence35% insufficent knowledge25% underestimation of influences13% forgetfulness, errors, mistakes9% reliance upon others without sufficient control6% objectively unknown situation4% others8%krishnamurthy [2007]matousek & schneider [1976], krishnamurthy [2007]motivation13reasons for structural failuresudden failure, subtotal loss of equilibrium failure with collapse failure without collapse other types of failure66%13%29%11%10%unacceptable conditions, subtotal excessive cracks errors in dimensions and support conditions deflections and change of shape other unacceptable conditions33%16%8%7%6%motivation14hyatt regencey walkway collapsethe hyatt regency hotel walkway collapseoccurred on july 17, 1981, in kansas city,missouri, killing 114 people and injuring216 others. at the time, it was thedeadliest structural collapse of u.s.history. one of the defining features ofthe hotel was its lobby, which featured amultistory atrium spanned by steel, glassand concrete walkways on the second,third and fourth levels suspended fromthe ceiling. the walkways were 37m longand weighed 29,000 kg. the fourth levelwalkway aligned directly above thesecond level walkway.krishnamurthy [2007]motivation34%34%19%9%4%15motivation. structural failure16

hyatt regencey walkway collapseoriginal designhyatt regencey walkway collapseactual constructionconstruction difficulties resulted in a subtle but flawed design change thatdoubled the load on the connection between the walkway support beamsand the tie rods carrying the weight of the second and fourth floorwalkways. this excessive load caused a lower bold to pull through thebeam so that the upper walkway collapsed upon the one below.motivation. structural failure17the engineers who had approved thefinal drawings were convicted by themissouri board of architects, professional engineers, and land surveyors ofgross negligence, misconduct, andunprofessional conduct in the prac-ticeof engineering; they all lost theirengineering licenses in the state ofmissouri and texas. while the designcompany was discharged of criminalnegligence, it lost its license to be anengineering firm. at least 140 millionwas awarded to victims and theirfamilies in civil lawsuits.ethics in engineering practise & research. whitbeck [1998]motivation. structural failure18mechanicshyatt regencey walkway collapsemechanicsME333solid mechanicsME338rigid bodiesthe hyatt regency tragedy remains a classic model for the study ofengineering ethics and errors. “investigation of the kansas city hyattregency walkway collapse” us department of commerce [1982]motivation. structural failure19dynamicsE15fluid mechanicsME351deformable bodiesME80staticsE141.1 mechanics20

basic quantitiesidealizationsparticle. a particle has a finite mass but a size that can beneglected. for example, the size of the earth is insignificantcompare to the size of the orbit; therefore the earth can bemodeled as a particle when studying planet motion. length. meter [m] time. second [s]rigid body. a rigid body is a combination of a large number ofparticles with all particles remaining at a fixed distance fromone another. mass. gram [g]concentrated force. a concentrated forceis a representation of loading as a singlepoint force. this is justified if the load isapplied to an area which is small compared to the overall size of the body. force. newton [N]1.2 fundamental concepts21newton‘s three laws of motion22weightSI systemW m·gW weight (derived quantity)m mass (basic quantity)g acceleration due to gravityg 9.81 m/s2 first lawequilibriumifF 0 then v const. second lawaccelerated motionF m·a third lawactio reactioFAB - FBA1.2 fundamental conceptsFPS systemm W/gm mass (derived quantity)W weight (basic quantity)g acceleration due to gravityg 32.2 ft/s2FABFBA1.2 fundamental concepts231.2 fundamental concepts24

systems of unitssystems of unitsSI systembasic units meters [m] seconds [s] kilogram [kg]derived unit Newton [N kg · m /s2]FPS systembasic units feet [ft] seconds [s] pounds [lb]derived unit slug [slug lb · s2/ft]1.3 units of measurement25conversion of units1.3 units of measurement1.3 units of measurement26prefixes271.4 international system of units28

philosophiae naturalis principia mathematica. isaac newton. [1687] syllabus 7 e14 - applied mechanics: statics syllabus 8 e14 - applied mechanics: statics.