SUMMARYA basic problem in the ÿnite element force method is that of obtaining a sparse and banded selfstress matrix and a sparse and banded structure exibility matrix. Traditionally the self-stress matrix is obtained through the application of algebraic procedures to the equilibrium matrix. The self-stress matrix for an indeterminate structure is not unique, and it is possible to obtain another self-stress matrix from an existing one through algebraic operations and grouping of redundants. The purpose of this paper is to describe and test an algorithm, called REDUC, which combines the vectors of the self-stress matrix obtained from the LU procedure of the force method. The rows of the transpose of this matrix are combined by using a special form of the Gaussian elimination technique. A plane frame example is presented to demonstrate the algorithm at work. The algorithm REDUC is applied to a plane truss and physical interpretation of the resulting self-stress matrix highlights the grouping of redundants, improved sparsity and bandwidth. Improvements in the conditioning and bandwidth of the structure exibility matrix are also observed. The algorithm yields results similar to those of the turn-back LU procedure, but requires less computation time and programming e ort.
This paper presents a more realistic and comprehensive static analysis technique for structures having non-prismatic members. In the proposed method a general stiffness matrix for non-prismatic members that is applicable to Timoshenko beam theory has been derived. The stiffness coefficients have been determined for constant, linear, and parabolic height variations of members, employing analytical and (or) numerical integration techniques. Uniform, triangular, and trapezoidal distributed loads over the entire member or along any part of it, concentrated loads, moments at points on the member, and any of these load combinations are taken into consideration to determine the fixed-end forces. A computer program has been coded in Fortran which analyses two-dimensional frames using the proposed stiffness matrix and fixed-end forces for a wide range of external loads. The fixed-end forces may include the effect of shear deformations. The importance of the shear deformations in non-prismatic members with high depth-to-span ratios is shown using numerical examples. The accuracy of the proposed analysis technique is verified by comparing the results of the numerical examples with those obtained from the general analysis program SAP90 using a large number of subelements. Key words: computer programs, fixed-end forces, loads (forces), non-prismatic (tapered), shear deformations, stiffness, structural analysis.
In this study, structural defects of existing 709 reinforced concrete (RC) buildings in Eskisehir Province were represented. Structural defects such as gaps between adjacent buildings, strong beam-weak column, mezzanine floor, short column, corner column, discontinuous frame, anchorage beams, long span, segregation, corrosion, inconvenient column/beam lateral reinforcement, low concrete strength and inconvenient steel reinforcement were determined in the study. It was determined that %35 of existing buildings have discontinuous frame, %16 of them have long span problem. It was also observed that nearly %40 of the buildings have no column/beam lateral reinforcement and %70 of them have inadequate gaps.
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