Parametric Study of Steel Structure

CHAPTER FOUR

PARAMETRIC STUDY AND DISCUSSION

4.1 GENERAL

Previous chapter describes the procedures how the model is done for the analysis and how the design section is obtained.In this chapter we will show the graphs for the amount of steel of the gable frame or truss with respect to various parameters associated with the gable frames or trusses.The graphs will indicate various difference in steel amount among various gable frames and trusses with respect to height/width ratio,span and column height.

4.2 MODEL INFORMATION

We have taken an industry building located at Gazipur i.e, in exposure B and providing design wind speed 215 km/hour according to BNBC code,having 160 feet length and 10 feet bay for every gable frame and truss model.Both the gable and truss models are subjected to dead load of 8 psf for roof and roof structures and the self weight of each member they consist and both external and internal wind pressure as per BNBC code.In each model there has been considered that the wind is coming both from perpendicular to the ridge and parallel to the ridge as per BNBC code suggested.There have been taken nine load cases i.e, one dead load and eight wind loads also made eight combinations by adding each wind load case with dead load . After making analysis with software named STADD.Pro the bending moment and the axial force was found for each gable model and similarly the axial force for truss member of each truss model. Among the eight combinations the largest momemt and axial force has been taken as design moment and axial force,for truss model thus only get design axial force of top chord ,bottom chord,vertical and diagonal member.With respect to these forces and moments members have been designed according to steel design procedure for combined bending and axial force and compression member.Gable beams and columns are designed for...