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Heavy Load on Concrete Slabs


Quiz Questions

1.The structural design of a concrete floor slab on grade is primarily controlled by the stresses caused by moving live loads and in some cases the stationary loads.
True
False
2. The maximum allowable stationary live load is limited by both the positive bending moment stress under the load and the negative bending moment stresses occurring at some distance from the load.
True
False
3.When a wall is placed on anew thickened slab or an existing concrete floor slab on grade. It can weigh from several hundred to several thousand pounds per linear foot. The design table used for determining thickness required under walls is developed by Staab and is based on the theory of beam on a liquid foundation subjected to concentrated loads.
True
False
4.According to table 3-1 the maximum allowable stationary live load on a 8 inches thick slab with 650 Ib/in2 is :
1003 Ib
1094 lb
1185 Ib
1276 Ib
5.For a wall load of 800 Ib/lin ft. on the middle of a concrete slab with flexural strength of 700 Ib/in2 , the minimum thickness of the slab according to table 3-2 is:
4 inches
5 inches
6 inches
6.The subgrade provides foundation for supporting the floor slab and base courses. As a result the required floor slab thickness and the performance obtained from the floor during its design life will depend in a large part, on the uniformity and bearing capacity of the subgrade. It is desirable to know the maximum support potential for the particular subgrade.
True
False
7.“Frost action” include surface heaving during freezing and loss of bearing capacity upon defrosting.
True
False
8.For a given water-cement ratio, the concrete strength likely to be obtained in a given locale depends primarily on the aggregate sources available. Maximum particle size and quality of the coarse aggregate will have a pronounced effect on concrete strength as will the gradation of the blended coarse and fine aggregate.
True
False
9.Figure 5-3 shows:
Joint sealant details
Design thickness for reinforced floor plan
Typical floor slab joint layout
Reinforcement for odd-shaped slab.
10.The design of jointed fiber concrete (JFC) floor slabs is based upon limiting the ratio of the concrete flexural strength and the maximum tensile stress at the joint, with the load either parallel or normal to the edge of the slab, to a value found to give satisfactory performance in full scale accelerated test tracks.
True
False