Load-carrying capacity of welded K-type joints inside floor truss systems

Pooya Saremi,Dan Pada,Jyrki Kesti,Jari Puttonen,Wei Lu

doi:10.23998/rm.74444

Abstract

The load-carrying capacity of a K-type joint inside a floor truss is studied both experimentally and numerically. The joint tested is a scaled-down, isolated joint. The tubular braces, plate chord, and division plate are made of SSAB Domex steel. Comparison of load displacement curves received by finite element analyses with curves obtained from tests confirms that numerical models describe joint behaviour reasonable. The paper demonstrates that joints with high load-bearing capacity can be investigated experimentally by scaling the dimensions of the joint down when testing devices can affect the required capacity of the joint. The results presented can also be used for optimizing failure mechanism of similar joints in practice.

Highlights

The building industry widely uses trusses in floor systems to get benefits of long spans and high strength-to-weight ratio
The corresponding relative displacement of the tension or compression brace to the chord are measured by four Linear Variable Displacement Transducers (LVDTs)
It seems that the deformation mode of the joint is sensitive to the imperfections that may arise from assembly and manufacturing of the test specimens

Summary

Introduction

The building industry widely uses trusses in floor systems to get benefits of long spans and high strength-to-weight ratio. In order to attach the specimen to the test set-up, end plates are welded to the ends of the chord and the braces. The corresponding relative displacement of the tension or compression brace to the chord are measured by four Linear Variable Displacement Transducers (LVDTs). The plan of these LVDTs (S-7 to S-10) is shown in Figure 3 (b). One end of each LVDT is attached to the point at the mid-length of the corresponding brace, and the other end to the intersection point of the mid-lines of chord and division plate. The test was stopped when the load applied to the joint was about 10% of the maximum load taken by the joint

Results of joint tests

Methods

Conclusions and future researches