Dugga Flashcards
Describe, with an example, the mechanical behavior of a two-way reinforced concrete slab. What is meant by plastic stress redistribution? Give the conditions for a kinematically possible failure mechanism and give some examples of such mechanisms.
Reinforced concrete slab
Describe, with an example, how the load on a rectangular two-way slab is distributed between the supports and what it means for the reaction forces along the supports. Describe how the load distribution is influenced by the reinforcement arrangement.
Reinforced concrete slab
Explain the basic principles of the strip method and give some examples of possible load distributions for a rectangular slab with uniform load.
Reinforced concrete slab
Describe how the bending moments in a rectangular slab with at least one statically indeterminate strip can be redistributed (three steps) in design on the basis of plastic analysis.
Reinforced concrete slab
Describe how rearrangement of the reinforcement in a rectangular slab can influence the stiffness of the slab and the load-bearing capacity. How should this be considered in design based on plastic analysis?
Reinforced concrete slab
Explain how the equilibrium condition for uniformly loaded slab elements at edges and corners depends on the support conditions (edge supports and corner supports).
Reinforced concrete slab
Explain the principles for how the average moment in corner supported elements can be redistributed in the transverse direction.
Reinforced concrete slab
Describe the principles for design on the basis of theory of plasticity and the basic assumption for the sectional response. Explain the meaning of ‘lower bound solution’ and ‘upper bound solution’?
Reinforced concrete slab
In what way will the behavior and the resistance of concrete beams be influenced by prestressing? What is meant by full and partial prestressing? Describe in what way the cracking behavior of a partially prestressed concrete beam is improved compared with a reinforced concrete beam.
Prestressed concrete structure
How is the effective prestressing force defined? Describe the difference between the tendon force approach and the strain compatibility approach for stress analysis of prestressed concrete members. When is it necessary to use one or the other method?
Prestressed concrete structure
Show the derivation of expressions for initial concrete and steel stresses in case of a prestressed member with centric pretensioned steel on the basis of the strain compatibility approach. How can the expressions be expanded to beam sections?
Prestressed concrete structure
Show how the effective prestressing force (initial value), at a certain section x, in a posttensioned beam can be determined from the tendon force in the same section (i.e. the force in the tendon in section x immediately after tensioning and anchoring).
Prestressed concrete structure
Explain why prestressing steel must have considerably higher strength than ordinary reinforcing steel. Show the derivation of a constitutive relationship for prestressing steel with regard to relaxation, a) when the steel strain is constant in time, b) when the steel strain varies.
Prestressed concrete structure
A prestressed concrete member with centric pretensioned steel is subjected to a sustained axial tensile force Nl (with long term effects). Show the derivation of an expression for the final concrete stress assuming that the section is uncracked for the long-term load.
Prestressed concrete structure
How is the flexural and shear cracking influenced by prestressing compared to a reinforced concrete beam? Describe various types of shear failures that may occur in a prestressed beam. How is the shear resistance influenced by prestressing compared to a reinforced concrete beam.
Prestressed concrete structure
