Investigation On Bolted Connection With Enlarged Holes Under Static Shear

As the bolted connection is widely used, the enlarged holes are also used byengineers. The studies on bolted connection with enlarged holes focus on friction typebolted connection and energy dissipation capacity of connection with enlarged holes.Based on the Design Specification of High Strength SteelStructures and the research ofbolted connection, experimental, numerical calculation and theoretical analysis havebeen done on the bearing and friction of bolted connection. The results show the failuremodes are almost the same between normal and enlarged holes, and different holescorrespond to different reduction factor.Based on30experiments of high strength steel bolted connection with differentoversized and slotted holes, the failure mode and bearing strength are well known. WithprovenFEM, the reduction factor is obtained.The influence of bolt size, reamingposition,strength of steel and hole sizes were studied. The results show the bolt size,strength of steelhave no effect on the reduction factor and the enlarged holes on the firstrow of loading end will influence the performance of connection. If the enlarged holesare on the first row, the reduction factor can be0.85and0.60for oversized and slottedholes.The slip factor of Q550and Q690with blasting and sandblastingsurfaceareobtained by experiment. And the thesisalso investigates the strain relaxationbefore and in the process of loading. The loading process can be divided into3parts:friction, slip and bearing. The friction coefficient of high strength steel is a littlelowerthan the general ones.There is a non-uniform distribution of force transfer over the length oflong bolted joints. The end fasteners will reach their critical shear deformationand fail before the full strength of each fastener can be achieved. Finite elementmodel was established to investigate the resistance of long bolted joints withenlarged holes. It’s found that An/Asratio and strength of steeldo notsignificantly affectthe reduction factor. For long connection with oversized andslotted holes, the reduction factorcan be taken as0.95and0.80.The study enlarges the existingstudies on bolted connection at home and abroad, giving reference to later studies and engineers, which helps the use of bolted connectionwith enlarged holes.