IS: 1343-1980 limits the minimum characteristic strength of prestressed concrete for post-tensioned work and pretension work as
A simply supported post-tensioned prestressed concrete beam of span L is prestressed by a straight tendon at a uniform eccentricity ‘o’ below the centroidal axis. If the magnitude of prestressing force is P and flexural rigidity of beam is EI, the maximum central deflection of the beam is
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The stress block in concrete for an estimate of ultimate strength in flexure of a prestressed beam
In the Limit state design of prestressed concrete structures, the strain distribution is assumed to be
Match List-I (Post-tensioning system) with List-ll (Type of anchorage) and select the correct answer using the codes given below the lists:
List-I
A. Freyssinet
B. Gifford-Udall
C. Lee-McCall
D. Magnel Blaton
List-II
1. Flat steel wedges in sandwich plates
2. High strength nuts
3. Split conical wedges
4. Conical serrated concrete wedges
Match List-I (Post-tensioning system) with List-ll (Arrangement of tendons in the duct) and select the correct answer using the codes given below the lists:
List-I
A. Freyssinet
B. Gifford-Udall
C. Lee-McCall
D. Magnel-Blaton
List-ll
1. Single bars
2. Wires evenly spaced by perforated spacers
3. Horizontal rows of four wires spaced by metal grills
4. Wires spaced by helical wire core in annular Spacer
An ordinary mild steel bar has been prestressed to a working stress of 200 MPa. Young’s modulus of steel is 200 GPa, Permanent negative strain due to shrinkage and creep is 0.0008. How much is the effective stress left in steel?
What is the allowable upward deflection in a prestress concrete member under serviceability limit state condition?
At the time of initial tensioning, the maximum tensile stress immediately behind the anchorage should not exceed which one of the following?