SUMMARYThis paper presents the implementation of Reissner's (J. Appl. Math. Phys. 1972; 23:795-804) straindisplacement relations for a planar beam using a variable order secant matrix (VOSM) technique. The secant matrices are formed using a Taylor expansion of the strain energy and hence the order of the secant and tangent matrices to be included in the nonlinear analysis can be varied depending upon the degree of nonlinearity involved in the problem. Nevertheless, a maximum of 24 matrices is sufficient to obtain predicted internal stress resultants to within 0.2% of the converged solution in all the problems tested. Using a three-noded isoparametric beam element, the accuracy of the VOSM method is demonstrated for the elastic postbuckling of arches.

Double layered grid space structures are well known in the building industry for their ability to cover large areas. This paper presents the results of a parametric study on the various factors affecting the flexural behavior of double layered grid space structures, considering (i) various support arrangement (ii) concrete slab at the top and (iii) an experimental investigation on a full scale space grid. Based on the study it was concluded that top concrete slab enhances not only the strength of top chord compression members but also increase the strength and stiffness of the system with a fail safe system. It was found from the study that atleast 20% saving in steel is possible with a mid edge supported system.

The primary objective of the paper is to investigate the post buckled behaviour of the single-layered Kite geometry dome developed using a novel crystallographic parameterisation principle. Both triangulated and non-triangulated domes are evolved based on the crystallographic parameterisation principles. It brings in a unique nomenclature for identifying different tessellations in reticulated single-layer dome configurations. This nomenclature brings in a physical meaning to dome tessellations instead of being called by the inventors such as Schwedler dome etc. In this paper, the effect of surface pattern on the load capacity of dome configuration is demonstrated with the comparison of domes having different surface patterns. The comparison of post-buckling behaviour of two different single-layer dome configurations - Kiewitt dome and Kite dome is presented. Despite having rigid nodal joints, the load capacity of the dome is significantly reduced when subjected to unsymmetrical and collateral loads due to the localised effect of these loads and the increased chance of snap-through compared to symmetrical uniform loading acting all over the structure. The Kite geometry have higher performance under uniform gravity loading with a low rise to span ratio.

No abstract

No abstract