Slippage controlled threaded rebar joint in reinforced concrete

A reinforced concrete structure having improved seismic resistance, comprising:

• a concrete structure, first and second rebar elements embedded in said concrete structure, said first rebar element having an internal thread at a first rebar end, said second rebar element having a male thread between a stop means and a second rebar end, said second rebar element being shorter between said stop means and said second rebar end than the length of said internal thread, said male thread being threaded into said internal thread, said first rebar end being axially preloaded against said stop means with sufficient force to elastically deform said male and female threads from a normal undeformed condition into substantially more uniform contact along opposing thread surfaces of said ends thereby to reduce axial movement of said rebars relative to each other and said concrete structure under cyclic axial loading of said structure.

A splice joint made with first and second concrete reinforcing rods, one of said rods having an enlarged head at a first rod end, a blind axial bore in said head opening at an end surface of said first rod end, an internal thread in said bore, the other of said rods having a shoulder and an external thread between said shoulder and a second rod end, the axial length between said shoulder and said second rod end being shorter than the axial length of said internal thread, said exterior thread being threaded into said internal thread so that said end surface bears against said shoulder, said first and second concrete reinforcing rods being torqued together to develop an axial load of said internal and external thread near to but lesser than the characteristic yield strength of said rods.