6-21. When modified with a metal roof, extended  rafters,  and  screened–in areas, a 16- by 32–foot wood–frame tent becomes what type of hut? 1. Southeast  Asia 2. Caribbean 3. Wood-frame 4. Tropical 6-22. When two 4-seat latrine boxes are set up side by side, what size pit is  required? 1. 3 by 6 ft 2. 2 by 6 ft 3. 3 by 7 ft 4. 4 by 8 ft 6-23. How  many  trough-type  urinals  should be furnished with an 8–seat latrine? 1. One 2. Two 3. Three 4. Four 6-24. Which  of  the  following  conditions normally  indicates  the  need  for steel  piles? 1. Driving  through  compressible soil 2. The  requirement  for  95-ft  piles 3. Light loads must be supported 4. A retaining wall is needed 6-25. Which of the following features is used to designate the size of a pier? 1. Length 2. Height 3. Width 4. Diameter of the piling 6-26. A pier is protected against shock damage from a ship tied alongside by a system of 6–27. The two main components of a timber trestle are 1. bents  and  abutments 2. substructure  and  superstructure 3. bracing and caps 4. decking  and  footings 6–28. Which  of  the  following  conditions normally  require(s)  trestle  bents? 1. Soft or marshy ground 2. Swift  currents 3. Deep water 4. Solid dry ground or shallow water 6–29. Which of the following is considered  a  vertical  structural member? 1. Post 2. Cap 3. Sill 4. Girder 6–30. How much overlap is figured in when calculating   center-to-center horizontal  distance  between  bents? 1. 1 ft 2. 2 ft 3. 3 ft 4. 4 ft 6-31. What is the usual length of girder stock? 1. 10 ft 2. 12 ft 3. 13 ft 4. 14 ft 6-32. What is the minimum width of a single-lane  trestle? 1. 12 ft 2. 14 ft 3. 16 ft 4. 18 ft 1. batter piles 2. bearing piles 3. stringers 4. fender piles 36