GRAPHIC PACKAGE FOR SEISMIC ANALYSIS OF FRAMED STRUCTURES

Abstract

With the onset of computers, the analysis of wide ranging and complex civil engineering problems has been made quite easier and more accurate. However the interpretation of the input/output is tiring and monotonous thus offsetting the advantage otherwise gained by employing computers. Computer graphics helps overcome this drawback. This branch has a. tremendous potential, for use in civil engineering problems. In thiS study, the need for generating artificial earthquakes for seismic analysis of structures and alongwith it the need to plot the generated output has been established. A programme 'ARTIEQ' originally written by Ruiz and Penzien is suitably modified to get elastic response spectra. Using this program, four types of artificial earthquake motions - types A, B, C and D - are generated. A graphic package' PLTEQ which plots the acceleration, velocity and displacement Vs time and Response spectra has been developed. This package has a wider range of options to plot one or more of the above records. Another package PLTPT which plots the Tripartite plot of an earthquake has also been developed. These two pack-ages serve as post-processors to the ARTIEQ program. For the seismic analysis of framed structures, generated or recorded earthquake motions may be used. Many Standard Structural analysis programs are available for dynamic analysis of structures. The basic input for these programs is in the form of nodal and element data, loading, material and geometry data etc. While for small frames, the nodal element data can be completely input, it may prove to be an unwanted exercise for big frames. Therefore many structural analysis programs have a proyision to generate nodal element data once a minimum data is input. However, on generation, random and systematic checks are to be carried out for this data. This is best done by drawing a 3-Dimensional view of a build-ing frame. Keeping this in view, a package CAL3D has been developed. 'This can plot the 5-0 view, front view, plan and side view of a frame. All these help in checking the correct-ness or otherwise of generated data. They serve as preprocess-ors to the structural analysis program. As a post processor, the deformed shape is also plotted. This package has a provision to plot 3-D view of transmission towers as well. A very effective hidden - surface removal algorithm is incorpo-rated in the package. The FORTRAN listing of all these graphic packages are also included in the thesis. The graphic packages developed, as a part of this study, aim at making the earthquake generation and structural analy-sis programs, adaptive in the field of computer graphics. These packages form the basis for further design.