A two-wire feeder PQR has a load of 100 A at R and 50 A at Q,
both at p.f. 0.707 lagging. The impedance of PQ is (0.03 + j0.05)
Ω and that of QR is (0.07 + j0.015) Ω. If the voltage at the far end
R is to be maintained at 415 V, calculate the voltage at Q and P.
Determine the crippling load for a T-section of dimensions 10 cm. x 10 cm x 2 cm and of length 5 m when it is used as strut with both of its ends hinged. Take Young's modulus, E2.0x10^5 N/mm^2
A welded joint, as shown in Fig. is subjected to an eccentric load of 2500 N.
Find the size of the weld, if the maximum shear stress in the weld is not to exceed
50 N/mm 2
A double riveted double cover butt joint in plates 20 mm thick is made with 25 mm diameter rivets at 100 mm pitch. The permissible stresses are:
= 120MPa T = 100MPa 0 150MPa Find the efficiency of joint, taking the strength of the rivet in double shear as twice than that of single shear.
A double riveted lap joint is made between 15mm thick plates. The rivet diameter and pitch are 25 mm and 75 mm, respectively. If the ultimate stresses are 400 MPa in tension, 320 MPa in shear and 640 MPa in crushing, find the minimum force per pitch which will rupture the joint. If the above joint is subjected to a load such that the factor of safety is 4, find out the actual stresses developed in the plates and rivets.
A plate 60 mm wide and 12.5 mm thick is to be welded to another plate by means of parallel fillet welds. The plates are subjected to a load of 80 kN. Find the length of the weld. Assume allowable shear strength to be 60 MPa.
A vertical composite fluid column whose upper end is open to the atmosphere is composed of 50
inches of Mercury Hg (SG=13), 80 cm of oil (SG=0.82) and 95 cm of water. Determine the pressure in
PSI at the, a) Oil-water interface b) Water-mercury interface c) Base of the column.
An ascending grade of 2.1% intersects another grade at STA 12+598 whose elevation is 549m. The change in grade is -0.15% per 20m station. The two grades are to be connected by a parabolic curve 800m long. Determine the elevation (m) of the summit.
Design Environment Pavement slab, Baguio City (severe cold climate)
Required design strength = 3000 psi Slab thickness = 12 in.
Statistical data indicate a standard deviation of compressive strength of 250 psi is expected (more than 30 samples). Only air entrainer is allowed.
Available Materials:
Air entrainer: Manufacture specification is 0.15 fl oz/1% air/100 lb cement.
Coarse aggregate: 2 in. nominal
maximum size, crushed stone
Bulk oven-dry specific gravity = 2.573 Absorption = 0.1%
Oven-dry rodded density = 120 pcf
Moisture content = 1% Fine aggregate: Natural sand
Bulk oven-dry specific gravity = 2.54
Absorption = 0.2%
Moisture Content = 3.67%
Fineness modulus = 2.68
Find the following requirements:
Required Compressive Strength Water-Cement Ratio
Coarse Aggregate Requirement
Check Aggregate Size
Air Content (Use Maximum) Slump (Use Maximum)
Water Content
Cement Requirement Admixture
Fine Aggregate Requirement Final Batch Quantities (Adjusted Summary)
Design a non-air-entrained concrete mix for a small job with a nominal maximum aggregate size of 25 mm. Show your calculations and results as follows:
a.) Masses of components to produce 2000 kg of concrete.
b.) Volumes of components to produce 1 cubic meter of concrete.