100 likes | 205 Views
WORKSHEET1 General Structural Concepts. A. fundamental concepts. Q1. A person has a mass of 70 kgs. What is their weight in (kN). Weight is a force . Weight = Mass x g where g = 10 m/s 2 on earth 1kg of mass = 10N of force on earth. 100kg of mass = 1kN weight on earth. 0.7 kN.
E N D
A. fundamental concepts Q1. A person has a mass of 70 kgs. What is their weight in (kN) Weight is a force . Weight = Mass x g where g = 10 m/s2 on earth 1kg of mass = 10N of force on earth. 100kg of mass = 1kN weight on earth 0.7 kN a) on Earth (g = 10 m/s2)? We = 70 x 10 /1000 = b) on a roller coaster (g1 = 3 x g)? Wr = 70 x 30 /1000 = 2.1 kN Wr = 0.7 x 3 = c) on the moon (g2 = 0.17 x g)? Wm = 70 x 1.7 /1000 = 0.12 kN Wm = 0.7 x 0.17 =
a) Acting down on Surface S? b) Acting up on Block B? A. fundamental concepts Q2. What is the force: 3 kN (100 + 200) * 10 / 1000 ) = 3 kN The table pushes back with the same force that is put on it Q3. What is the pressure exerted: On Surface S if the base of Block B is 200 x 150 mm? P = F / A 100 kPa P = 3 / 0.20 x 0.15 = 100 kN/m2 =
5m Q4. What is the moment at: 2kN A 3m C B A. fundamental concepts Moment is a turning effect and equals force x distance M = F * D 10 kNm a) A? MA = 2 x 5 = 6 kNm b) B? MB = 2 x 3 = 0 kNm c) C? MC = 2 x 0 =
10kN 10kN 10kN 10kN 10kN 10kN 10kN 14.1kN 10kN Equilibrant 10kN 45o 10kN A. fundamental concepts Q5. a) Indicate the force or (forces) necessary to establish equilibrium (show the forces graphically) Equilibrant = √(102 +102) = 10 / sin45 = 14.1
F2= ? kN F1= 12kN A B C 3m 1m A. fundamental concepts Q5. a) Indicate the force or (forces) necessary to establish equilibrium (show the forces graphically) R1= ? kN Taking moments about B, Clockwise moment = 12 * 1 = 12 kNm ∑ M = 0 Anticlockwise moment = F2 * 3 = 12 kNm 4 kN F2 = 12 / 3 = b) What is the reaction at B (after you have restored equilibrium) ∑ V = 0 16 kNm R1 = 12 + 4 =
(a) (b) (c) (d) A. fundamental concepts Q6. Figures (a) to (d) show 4 structural assemblies. Identify the assemblies that have: a) the same topology. same no. of joints and same connectivity at each joint (a, c) (b, d) b) the same geometry and different topology joints in the same place but connectivity different (a, b) (c, d)
the purpose of structure is to provide the fabric of the space enclosure the function of structure is to resist all the forces acting (on the building) and to transfer them to supports (the ground) B. general principles Q7. What is the function of structure?
B. general principles Q8. What are the three main considerations we are concerned with when dealing with structure? • stability - equilibrium building must not move - up, sideways or overturn all forces and moments must balance • strength building & elements must not break / collapse • functionality building & elements must continue to serve their purpose must not deform too much
B. general principles Q9. Given the post-and beam arrangement as shown, describe Three ways of stabilising it. Draw and name them. • a) cross-bracing • b)knee-bracing • c)rigid joints • d)solid infill (shear panels) • e) build-in posts (rigid joints)