A field investigation of time-dependent shortening of columns and core walls in a reinforced concrete multistorey structure was recently completed by the Portland Cement Association of America. Strains were measured over a period of four years commencing during the construction period and continuing through subsequent occupation of the building. Diameter of columns, thickness of core walls, strength of concrete, and amount of reinforcement varied throughout the height of the 70-storey structure. Compressive strains at 27 different storeys were measured.
The paper compares the strengths of shear connectors given in CP 117, Parts 1 and 2 with the results of recent push-out tests made at the Building Research Station. Particular attention is paid to the effect of concrete strength and density on the static and fatigue strengths of connectors. Recommendations are made for the revision of the specified strengths, the extension of the range of concrete strengths over which connector strengths are specified and the inclusion of the strengths of stud connecfors embedded in lightweight concretes. John B. Menzies
The paper describes three phases of a scheme for reconstructing the area around Guildhall in the City of London. Two of these phases have been completed and the third is now under construction. The work has included the design both of new buildings and of modifications to existing and historically important ones. The first phase to be built consisted of an underground car park-also housing, temporarily, Magistrates' Courts-and an Exhibition Hall, and the second comprised the alteration and renovation of the building at the entrance to Guildhall. The third, and largest, embraces the provision of new ofices for the Corporation and the restoration to its former appearance of a part of the Guildhall Crypt. Much use has been made in the ofices of structural precast concrete, while, for the reinstatement of the Crypt, the adoption of a steel structure has seemed appropriate. C.J.E. Morris, A.M. Weneck and D.J.A. Alsop
The following is a precis of a paper which is filed in the Institution’s library (reference X(27)). Copies of the paper are available for borrowing by members of the Institution in the United Kingdom, or they can be consulted at the Institution. M.A. El-Gaaly and M.K. Khalifa
The deformational behaviour of single and multicell steel and concrete box girders is studied by reference to specific examples which incorporate variations in wall thickness, loaded length, stiffener size, diaphragm spacing, shape of section, curvature, and support positions. J.C. Chapman, P.J. Dowling, P.T.K. Lim and C.J. Billington
Dr. Cope (University of Liverpool, Department of Civil Engineering): 'Mr. Chairman, gentlemen, the contribution I would like to give is a joint one with Professor Sawko who very much regrets not being able to attend tonight.'