Improving the algorithm of choosing spacing and number of stiff supports against a concentrated force in steel-concrete beams

Anatoliy Petrov,Tetiana Dedilova,Serhii Sheptun,Artem Naumenko,Anatoliy Paliy,Andriy Paliy,Ivan Vysochin,Yana Kononenko,Oksana Yurchenko,Maryna Ihnatenko

doi:10.15587/1729-4061.2021.228862

Abstract

A steel-concrete beam was taken as the study object. The algorithm of selecting the number of stiff supports for the steel-concrete beam loaded with a concentrated lateral force in the middle of the span has been refined. Stiff supports served to join the steel strip with concrete to ensure their joint performance. The algorithm was refined based on the condition of equality of the longitudinal force in the steel strip from the action of the calculated load and the maximum longitudinal force obtained after setting the supports. In this case, the longitudinal forces in all stiff supports, as well as the spacing of the stiff supports should be the same. A disadvantage of the known algorithm consists in the complexity of determining the coefficient φb2 taking into account the effect of long-term concrete creep on the element deformation without cracks. This coefficient fluctuates widely and depends on many factors. Besides, it is also insufficiently studied. Calculations for determining the number and spacing of stiff supports in a steel-concrete beam were conducted according to the proposed algorithm and in the Lira software package. The forces acting on the supports and spacing of the supports were the same. The force acting in the support was 8941.5 N. When selecting characteristics of the steel-concrete beam, maximum longitudinal force in the steel strip was obtained. The longitudinal force amounted to 35726 N. The same longitudinal force was obtained from the diagram of longitudinal forces obtained after setting the supports. This study was aimed at improving the design of steel-concrete beams. A rational number and placement of stiff supports ensure savings: the required amount of building materials is reduced and their cost is reduced due to cutting labor costs for their manufacture and operation

Highlights

Industrial and civil construction is one of the most important industrial sectors in today’s world
As one of the development ways, rational number and placement of stiff supports will lead to savings due to both reducing the required amount of building materials and reducing their cost by cutting labor costs associated with their manufacture and operation
It should be noted that the method of joining component elements of the steel-concrete beams using stiff supports or flexible anchors is not always used

Summary

Introduction

Industrial and civil construction is one of the most important industrial sectors in today’s world. The concrete structures externally reinforced with steel in general, and beams in particular, have proven themselves as reliable structures fairly simple in manufacture As one of the development ways, rational number and placement of stiff supports will lead to savings due to both reducing the required amount of building materials and reducing their cost by cutting labor costs associated with their manufacture and operation. This approach assumes the practical value and relevance of the studies aimed at increasing the bearing capacity of steel-concrete beams

Literature review and problem statement

The aim and objectives of the study

Determination of length of the zero section:

Force acting on supports

Findings

Conclusions