1-. A concrete beam of rectangular cross section of size 300mm x 500 mm is prestressed with 750kN at an eccentricity of 100mm from the centre of gravity of the gross section with 500 mm2 of prestressing steel stress to 1500 N/mm2. Analyse the section for stress (find the stress in concrete at top and bottom fibre)

2- The same concrete is covering a span of 7m. It is subjected to live load of 20 kN/m. Evaluate the stresses at top and bottom fibres at mid cross section due to the effect of prestress, dead and and live loads. Assume unit weight of concrete to be 24 kN/m3

Consider the vector fields F = ze^xz cos y i − e^xz sin y j + xe^xz cos y k G = x^2 z i + xy^2 j + yz^3 k (a) Compute div F. (b) Use curl to determine which of F and G is conservative. (c) Find a function f such that your answer to part (b) is equal to ∇f. (d) Find ∇^2f.

QUESTION 1

Distinguish between solid waste and hazardous waste in terms of definition. Discuss the management of hazardous waste. [20 marks]

subject:enviromental enginnering

1. What are typical performance tests for asphalt mixture? Describe each test, device and parameters used to characterize the performance of asphalt mixture.

Explain the concepts of Boussinesq method (elastic theory), methods using tables, graphs and charts for the
determination of stress distribution in soils due to different types of loading

There are two major or general type of dimensions that defines the geometric shape. Kindly create FIVE EACH situation on as much geometric shapes you can to ILLUSTRATE them.   

1) What is the difference between a Ferrous and Non-Ferrous metal?

2) Describe what happens to metal when the percentage of carbon is increased.

3) What is the difference between a Thermoplastic and Thermoset? Give three examples of each.

4) List all of the plastic processing methods and give three examples of products that are made from each method.

In designing a sprayed seal, the objective is to determine an application rate for the bitumen so that the aggregate is partially embedded in the bitumen. Describe how the following factors influence the design calculations for the bitumen application rate, and the effect of changing each of these factors. a) Average Least Dimension (ALD) of the aggregate. b) The surface texture of the surface to be sealed

1. If you needed to reduce deflection in a loaded aluminum rectangular box beam in your structural design, which of the following variables would you INCREASE?  Which would be the MOST effective in reducing deflection?  

                                    L               W             w              H              h

2. For question 1 above, what material could you substitute for aluminum in your design to decrease the deflection? Why?  

3.   Which has the larger Area Moment of Inertia, a 2” x 2” square beam of high strength stainless steel or a 2” x 2” square beam of balsa wood? Support your answer qualitatively or quantitatively.  

4. Should the Elastic modulus of a beam change if the unsupported length of the beam is changed?  Why?

5.    What would be the percent change in deflection if a solid rectangular beam has its unsupported length changed from 30 inches to 36 inches?   SHOW YOUR CALCULATION. What does this tell you about the importance of unsupported beam length in structural design?

6.   Is the Modulus of Elasticity indicative of what the failure load of a beam would be? Why?

7.   Which has a higher resistance to deflection (that is, a smaller ratio of Dy/P), a solid square, 1”x1” beam, or a square box beam with outer dimensions of 1”x1” and inner dimensions of 0.95”x0.95”? (Assume that L and E are the same for both.) What advantages are there to using the box beam instead of the solid beam?

a reinforced T-beam is having a flange size 90cm×12cm and web size 30 cm×25 cm . if there are 6 bars of diameter 2cm, in tensile zone, find the moment of resistance of the section . if the MR has to be increased to 1.5 times the original MR . Calculate the additional reinforcement needed both in tensile as well as in compressive zone without changing the section. Assume both side cover as 5cm , c=52.5kg/cm², t= 1250kg/cm², m=20.

Determine when to use either the engineering, procurement and construction (EPC) contract model or the engineering, procurement and construction management (EPCM) contract model. When is it appropriate to use EPC and when is it appropriate to use EPCM. Provide recommendations on how to decide for civil engineering projects.

A brass pipe has an internal diameter of400mm and a metal thickness of6mm. A triple layer ofbigh tensile wire ofdiameter 3 mm is wound closely round it at a tension of500 N. Find (a) the stress in the pipe when there is no internal pressure; (b) the maximum permissible internal pressure in the pipe if the working tensile stress in the brass is 60 MNhn2 ; (c) the stress in the steel wire under condition O). Treat the pipe as a thin cylinder and neglect longitudinal stresses and strains. E, = 200GN/m2; Erl OOGN/m: