The stress distribution in a shear wall. (1970)
AuthorsJohnstone, P. G.show all
This thesis deals mainly with a prototype test performed on an eight storey shear wall. The dynamic stress distribution, obtained from the prototype wall as the building was being shaken; is compared with results obtained both from a finite element analysis and from a photqelastic model study of the shear wall. The aim was to show the validity of a finite element analysis when compared with a photoelastic model, and to evaluate the accuracy of both it and the photoelastic study in the prediction of the elastic stress distribution in a prototype shear wall,
A large part of the thesis is devoted to an experimental program in which a portable dynamic strain pick-up instrument, and an associated Dynamic Strain Bridge was developed. This instrument was capable of recording small dynamic strains as low as .015 microstrain. Photoelastic modelling techniques are also discussed in some detail
Comparisons between the results obtained from the prototype shear wall, the photoelastic model, and the finite element analysis were made mainly on the basis of the difference between the principal stresses and their orientation, The deflected shapes of the prototype and the finite element walls were also compared, and the theoretical frame/shear wall interaction was studied.
Floor slabs were shown to play a significant part in shear wall structures. The slabs stiffen the connecting beams in flexure, help prevent elastic instability, and probably aid in the ultimate strength of the shear wall by strengthening the spandrel beams and by acting as members in an effective truss within the wall.
Both the finite element and the photoelastic methods were shown to predict the stress levels in the prototype generally to within 20%. The need for floor slabs to be included in the finite element analysis was shown.