Deformation Behaviour of Friction Type High Strength Bolted Joints at Elevated Temperature

Abstract

In order to analyze the redundancy of steel frames in fire, it is important that the load-deformation behaviour of friction type high strength bolted joints at elevated temperature is clarified. In this paper, influences of plate thickness, end distance, fastening of bolts and steel temperature on the deformation behaviour of the bolted joints are discussed on the basis of the elevated temperature tensile test results. In case the plate is thin and the failure mode is tear-out, the ductility of the joints increases. However, if the failure mode is changed from tear-out to bolt in share due to increase of temperature or end distance, the ductility of the joints decreases. Fastening of bolts slightly affect the load-deformation behaviour of the bolted joints at elevated temperature.

Load–deflection behaviour of thin-walled bolted plates in shear at elevated temperatures

“…In the tests of Hirashima and Uesugi [9], gaps existed in the direction parallel to the loading direction between the bolt and plate at the beginning of the test and slip occurred, as clearly indicated by the recorded load-displacement curves.…”

“…In the tests of Hirashima and Uesugi [9], the bolt diameter/plate thickness ratio was very small (22/25 o1) and large bolt deformation and fracture were observed. Clearly, it is necessary to include bolt deformation and failure in the simulation model.…”

“…However, due to much bigger plate thicknesses used in the tests of Hirashima and Uesugi [9], it was no longer appropriate to retain 1/4 plate thickness as the mesh size. After trial and error, the best mesh size was found to be 1/20th the connected plate thickness at places such as the bolt-hole area.…”

“…shank of the bolt was modelled. During the entire simulation, both ends of the bolt shank were fully restricted; two small steel plates were placed on the tested plate to eliminate undesired out-ofplane deformation, as in the test set up described by Hirashima and Uesugi [9]. For tests using four bolts, due to symmetrical geometry, only half of the plate was modeled and symmetric boundary conditions (no plate in-plane movement, no rotation about the plate center line) were applied to the middle line of the test plate, as seen in Fig.…”

“…In all the above studies, none investigated the maximum deformation of the connection. Hirashima and Uesugi [9] appear to be the only one to have provided some experimental data for the maximum deformation, based on a series of tests for hot-rolled bolted plates in shear at elevated temperatures.…”