# Unknown

Confirmed CE board problems but the date of exam is still unknown or not yet confirmed.

## Hollow Circular Beam with Known Cracking Moment

**Situation**

A concrete beam with cross section in Figure CO4-2B is simply supported over a span of 4 m. The cracking moment of the beam is 75 kN·m.

1. Find the maximum uniform load that the beam can carry without causing the concrete to crack, in kN/m.

A. 35.2 | C. 33.3 |

B. 37.5 | D. 41.8 |

2. Find the modulus of rapture of the concrete used in the beam.

A. 4.12 MPa | C. 3.77 MPa |

B. 3.25 MPa | D. 3.54 MPa |

3. If the hallow portion is replaced with a square section of side 300 mm, what is the cracking moment of the new section in kN·m?

A. 71.51 | C. 78.69 |

B. 76.58 | D. 81.11 |

## Continuous Beam With Equal Support Reactions

**Situation**

A beam 100 mm × 150 mm carrying a uniformly distributed load of 300 N/m rests on three supports spaced 3 m apart as shown below. The length *x* is so calculated in order that the reactions at all supports shall be the same.

1. Find *x* in meters.

A. 1.319 | C. 1.217 |

B. 1.139 | D. 1.127 |

2. Find the moment at *B* in N·m.

A. -240 | C. -242 |

B. -207 | D. -226 |

3. Calculate the reactions in Newton.

A. 843.4 | C. 863.8 |

B. 425.4 | D. 827.8 |

## Continuous Beam With a Gap and a Zero Moment in Interior Support

**Situation**

A beam of uniform cross section whose flexural rigidity *EI* = 2.8 × 10^{11} N·mm^{2}, 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 |