SEC - Structural Engineering and Construction
Common name: Design
Engineering Mechanics, Mechanics of Materials, Structural Analysis, Design of Timber Structures, Design of Steel Structures, Reinforced Concrete Structures, Construction and Management
Situation
A beam of uniform cross section whose flexural rigidity EI = 2.8 × 1011 N·mm2, is placed on three supports as shown. Support B is at small gap Δ so that the moment at B is zero.
1. Calculate the reaction at A.
| A. 4.375 kN | C. 5.437 kN |
| B. 8.750 kN | D. 6.626 kN |
2. What is the reaction at B?
| A. 4.375 kN | C. 5.437 kN |
| B. 8.750 kN | D. 6.626 kN |
3. Find the value of Δ.
| A. 46 mm | C. 34 mm |
| B. 64 mm | D. 56 mm |
Problem
A tensile load of 8000 kg elongates a 1-m long square rod by 1 mm. Steel modulus of elasticity is 2 × 106 kg/cm2. What is the dimension of a side of the rod?
| A. 5 cm | C. 2 cm |
| B. 1 cm | D. 4 cm |
Situation
A temporary earth retaining wall consists of wooden plank driven vertically into the ground. The wall is designed to resist 2.4 m height of soil.
1. Calculate the maximum flexural stress.
| A. 12.7 MPa | C. 8.6 MPa |
| B. 14.2 MPa | D. 10.1 MPa |
2. Calculate the maximum shear stress.
| A. 1.11 MPa | C. 0.99 MPa |
| B. 0.33 MPa | D. 0.77 MPa |
3. Calculate the minimum thickness of the plank to prevent failure.
| A. 90 mm | C. 110 mm |
| B. 80 mm | D. 100 mm |
Situation
The truss shown in is made from timber Guijo 100 mm × 150 mm. The load on the truss is 20 kN. Neglect friction.
1. Determine the minimum value of x in mm.
| A. 180 | C. 160 |
| B. 150 | D. 140 |
2. Determine the minimum value of y in mm.
| A. 34.9 | C. 13.2 |
| B. 26.8 | D. 19.5 |
3. Calculate the axial stress of member AC in MPa.
| A. 1.26 | C. 1.57 |
| B. 1.62 | D. 1.75 |
Situation
The bridge truss shown in the figure is to be subjected by uniform load of 10 kN/m and a point load of 30 kN, both are moving across the bottom chord
Calculate the following:
1. The maximum axial load on member JK.
| A. 64.59 kN | C. -64.59 kN |
| B. -63.51 kN | D. 63.51 kN |
2. The maximum axial load on member BC.
| A. 47.63 kN | C. -47.63 kN |
| B. -74.88 kN | D. 74.88 kN |
3. The maximum compression force and maximum tension force on member CG.
| A. -48.11 kN and 16.36 kN |
| B. Compression = 0; Tension = 16.36 kN |
| C. -16.36 kN and 48.11 kN |
| D. Compression = 48.11 kN; Tension = 0 |
Situation
Diagonals BG, CF, CH, and DG of the truss shown can resist tension only.
If W = 3 kN and P = 0, find the following:
1. the force in member CF.
| A. 4.76 kN | C. 4.67 kN |
| B. 4.32 kN | D. 4.23 kN |
2. the force in member BF.
| A. 3.2 kN | C. 3.4 kN |
| B. 3.3 kN | D. 3.5 kN |
3. the force in member DH.
| A. 2.8 kN | A. 2.5 kN |
| B. 2.8 kN | D. 2.7 kN |
Situation
Flexible cables BE and CD are used to brace the truss shown below.
1. Determine the load W to cause a compression force of 8.9 kN to member BD.
| A. 7.80 kN | C. 26.70 kN |
| B. 35.64 kN | D. 13.35 kN |
2. Which cable is in tension and what is the tensile reaction?
| A. BE = 12.58 kN | C. BE = 6.29 kN |
| B. CD = 6.29 kN | D. CD = 12.58 kN |
3. If W = 20 kN, what will be the tensile reaction of member CE?
| A. 6.67 kN | C. 0 |
| B. 13.33 kN | D. 10 kN |
