CMGT 410 Midterm #2 100% Correct!

Soldier Pile Walls are very strong and so they never require tiebacks - ANSWERFalse Soil nails are typically mechanically tensioned. - ANSWERFalse Helical, or mechanical, tieback anchors are usually the most economical retaining wall tieback. - ANSWERFalse Ground freezing is an effective way of cutting off water. - ANSWERTrue Triple fluid jet grouting systems use air and water to erode the soil and yield a higher quality of soil-cement mix. - ANSWERTrue Thru-point / tie-point connections to soldier piles intersect through the middle of the piles in order to avoid twisting pressures. - ANSWERFalse If the earth around the trench box is sloped or benched, then the top of the trench box needs to be at least - ANSWER18 Inches Trench boxes must be 2' from the bottom of the trench. - ANSWERTrue What is an acceptable amount of settlement cause by the underpinning process? (Assume uniform settlement.) - ANSWER0'' to 1/2'' The original structural engineer of the structure to be underpinned is the engineer who has to design the underpinning. - ANSWERFalse Jet grouting used as underpinning is never reinforced. - ANSWERFalse Identify three safety concerns with underpinning AND identify a way to mitigate or eliminate each safety concern you identified. - ANSWERDeep trenches could cave in due to vibrations - Use bracing on trenches to mitigate this concern Erosion while digging in foundation - required to use sheeting on sides of walls. Surcharge load of machines or other heavy equipment - be aware of the weight you have near the place you are digging and keep it at a safe distance. Identify two scenarios where underpinning might be required. - ANSWER1. C