Simple Method of Approximate Calculation of Statically Indeterminate Trusses

Janusz Rębielak

doi:10.1142/s0219876218400261

Abstract

The paper presents principles of the simple method which makes possible approximate calculations of statically indeterminate truss systems in two stages. The two-stage method applies rules of other methods used for calculations of statically determinate trusses. In each of the two stages, there are considered statically determinate trusses, patterns of which are obtained as results of suitable withdrawing of appropriate members from the pattern of the basic statically indeterminate truss. There are presented results of calculations carried out for two cases of load for selected type of plane truss together with comparison of outcomes obtained by means of using appropriate computer software.

Highlights

In the theory of structures, there are two equivalent general research methods
The second general research method consists of the energy conservation law and is mainly applied for determination of strains of the statically indeterminate structural systems
In order to verify correctness of theoretic assumptions of the two-stage method, a series of computations of the simple form were carried out of the plane statically indeterminate truss having the form of a basic truss shown in Fig. 2, built of steel members, having clear span equal to 5.00 m and the construction depth equal to 1.00 m

Summary

Introduction

In the theory of structures, there are two equivalent general research methods. The first one is based on principles of static equilibrium as well as on the geometry of stains and it is applied in computational procedures of the statically determinate systems [Kolendowicz (1993)]. The second general research method consists of the energy conservation law and is mainly applied for determination of strains of the statically indeterminate structural systems. It applies the concept of principle of virtual work defined in two ways. Methods of calculations of statically indeterminate systems have to make possible the exact computation of force values acting in members of such systems. Results obtained by their application are the basis for engineers, who are obliged to design safe and economic structural systems for various purposes, like, for instance, roof structures in the building industry. Final values of forces acting in particular members of the basic statically indeterminate truss are resultants of forces calculated in each stage in the counterpart members of the statically determinate trusses

Definition of Research Problem and Proposal of a Method for Its Solution

Results of Calculations and Comparative Analyses

Conclusions