Investigation on the Seismic Performance of High-Strength Bolt-Rubber (HSBR) Connection in a Steel Frame

Abstract

The existing buildings can be improved under the seismic effect by adding rubber to the bolts in the connection. The buildings when maintenance work is happening there is a problem many times and it should be evacuated and requires high cost. This study aims to maintain the building without having to remove it and at a very low cost compared to other methods. This study includes six models divided into two groups. The two groups differ in terms of the number of bolts in the contact area between the column and the beam in the steel frame. The first group models contain four bolts in the connection area and the second group forms contain five bolts in the contact area. Each group includes three models representing the first form of a reference model that has not rubber material around the bolts in the connection area, the second model contains 150% rubber than a bolt diameter around one bolt of the connection area, and all the bolts in the connection area in the third model are warped with rubber. The presence of rubber around one bolt gave a load, displacement, drifting, damping ratio, ductility index energy dissipation close to models where all contact bolts are warped with rubber material.

Conclusion

Based on the results presented in this research and the observations obtained from the numerical analysis, the conclusions drawn from this work can be summarized as follows:

• When comparing the load and displacement value of the reference model and that contain rubber, note that the displacement value and the load value have increased significantly because the rubber is a hyperelastic material, and one of the properties of this material is to make the rubber within the elastic phase, as the model is deformed and then returns to its original position, where this principle is called (deformation recovery) and the rubber continues in this case until it reaches the stage of yield and then to the ultimate stage and failure occurs.
• The presence of rubber around one bolt gives a similar drift rate to the case of wrapping all the fixing bolts with rubber
• The ductility of the model that contains one rubber-coated bolt in the case of the 4 bolts is not very different from the model that contains 4bolts coating with rubber, but in the case of the 5 bolts, the ductility of the model that contains 5 rubber-coated bolts is higher than the model that contains one bolt is rubber-coated due to the increase in the displacement of the model.
• For damping, the addition of rubber around all bolts in the connection improved the damping ratio a little more compared to the model containing rubber around one bolt in each contact of the models.
• Rubber around one bolt can dissipate a sufficient percentage of energy compared to wrapping all fixing bolts with rubber.
• Finally, through all the above calculations, can verify the validity of this study, which enables us to maintain the buildings by wrapping one bolt with rubber to make the building resistant to seismic effects, and this method will give a greater saving of time and cost than the other method used in building maintenance.